broiler chicken

Cereal gains form the largest portion of the poultry industry. The most important cereal in this industry is corn grain, but the presence of some issues, including the change and fluctuation of corn prices accompanied by a shortage of corn gain in some conditions in our country, have forced poultry farmers to explore different substitutional grains, such as wheat. Compared with corn, wheat grain has some advantages over corn, including improving the pellet quality and having more crude protein along with higher lysine, methionine, arginine, phenylalanine, tryptophan, threonine, and valine. However, two drawbacks to wheat grain have limited its usage in poultry diets in some conditions. On the one hand, wheat has lower metabolizable energy than corn. On the other hand, non-starch polysaccharides in wheat grain prevent energy availability and impede the growth performance of boilers. The most prominent non-starch polysaccharide known in wheat is arabinoxylan, which includes almost 10% of this cereal; these particular polymers have a great water-holding capacity of around 10 times their weight. Furthermore, having arabinose in the lateral chain has made it possible for non-starch polysaccharides to become water-soluble. These factors make a high-viscosity condition in the gastrointestinal tract causing a low enzyme-substrate interaction, resulting in weaker digestion and absorption of starch, protein, and fat and, consequently, lower energy retention, which reduces the growth performance of birds. One of the most appropriate methods to improve broiler chickens' performance and decline the negative effects of non-starch polysaccharides (NSPs) in wheat is to apply multi-enzymes. The classic method for enzyme supplementation is to add enzymes over a formulated diet (over the top). Another way for enzyme addition is to consider the nutrient matrix values for the enzyme, which is the most suitable method to decrease the cost of both enzyme and feed consumption. The current study aimed to apply the nutrient matrix values for three different multi-enzymes and evaluate their effects on the performance, water consumption, litter moisture, jejunal viscosity, and some characteristics of the gastrointestinal tract in broilers fed wheat-soybean meal to find an appropriate criterion for the most realistic nutrient matrix values for enzymes.

Three-hundred-day-old male broiler chicks of commercial strain (Ross 308) were studied with four treatments, five replications, and 15 chicks in each replicate in a floor pen. All data were analyzed using a randomized complete design. The four dietary treatments consisted of a wheat-soybean meal-based diet without enzyme (control group) and three wheat-soybean-based diets supplemented with enzymes A, B, and C, which were added at 170, 600, and 500 mg/kg DM, respectively. The nutrient matrix values were considered for enzymes. The effects of treatments on the performance, carcass characteristics, length and weight of intestinal segments, digestive organs weight, water-to-feed intake ratio, and jejunal viscosity were investigated at the end of 42 days.

Results of this trial showed that in the starter, finisher, and the whole period, feed intake was not affected by enzyme addition whereas only in the grower period of rearing and only adding enzyme B to the wheat-soybean meal-based diet significantly improved Average Daily Feed Intake (ADFI) (p < 0.05). In the starter period, only the enzyme A addition to a wheat-based diet improved Average Daily Gain (ADG) (p < 0.05). However, in the grower, finisher, and the whole period, ADG was improved by enzyme A and B supplementation (p < 0.05). However, feed conversion ratio (FCR) was not affected by enzyme addition in the starter period (p > 0.05), but using nutrient matrix values for enzymes A and B significantly improved FCR in the grower, finisher, and in the entire period (p < 0.05). Results showed that enzyme supplementation did not significantly affect the relative weight of the pancreas, liver, relative weight and length of the duodenum, jejunum, ileum, and cecum, water to feed intake ratio, and litter moisture (p > 0.05). Birds that received enzyme A and B had lower jejunal content viscosity at day 23 and higher abdominal fat at day 42 (p < 0.05). While carcass yield and thigh relative weight did not change by enzyme supplementation (p > 0.05), breast relative weight for birds that received enzyme A was significantly lower than control treatment and the enzyme C containing group (p < 0.05), and there was no significant difference among enzymes A and B (p > 0.05).

The results of the present study showed that the application of nutrient matrix values for enzymes A and B improved the performance of broiler chickens fed a wheat-soybean meal-based diet, and their matrix values could be used for feed formulation to reduce the cost of each kilogram feed. Moreover, the results of the current study showed that using the nutrient matrix value for enzyme C did not significantly affect broiler performance. For assurance, more experiments are needed to be designed to evaluate the nutrient matrix value of this enzyme.

Various factors have been reported to influence broiler chicken performance, including environmental conditions, nutrition, management practices, and genetics. One of the priorities in poultry production is the availability of effective alternatives to antibiotics, and the native strains of this type of alternative have various advantages. Probiotics as live microbial supplements in feed improve the microbial balance of the gastrointestinal tract and then improve animal health. Probiotics can enhance growth performance, support the immune system, aid nutrient digestion, and positively influence the microbial population of the gastrointestinal tract. Commercial probiotics are the most commonly used; however, screening the natural flora of the gastrointestinal tract has become a valuable approach in identifying effective probiotic strains. Selecting the optimal species for use in probiotic supplements is largely experimental and depends on their proven impact on the performance of living organisms. This project aimed to investigate the effects of indigenous probiotics on broiler chickens. The probiotics included strains of Lactobacillus reuteri isolated from native chickens in Oshnavieh, Shush, Shaft, and Masal, as well as Lactobacillus salivarius isolated from native ducks in Mazandaran. The study aimed to assess the impact of these probiotics on the performance, immune response, morphology, and gut lactobacillus population in broiler chickens. The single strain (Plr2) and combination strains (Plr9, Plr10, Plr11, and Plr12) were evaluated in a completely randomized design. There were seven treatments, each with four replicates, and 16 one-day-old Ross 308 broiler chickens per replicate. Treatments include 1) control: basic diet without any additive, 2) Positive control 2: basic diet + commercial probiotic, 3) Basic ration + 1.36×109 CFU/g L. Reuteri isolated from Oshnavieh native hen (Plr2), 4) Basic ration + 1.36×109 CFU/g L. Reuteri isolated from Oshnavieh native hen and L. salivarius isolated from Mazandaran native duck (Plr9), 5) Basic ration + 1.36×109 CFU/g L. Reuteri isolated from Oshnavieh native hen and L. salivarius isolated from Mazandaran native duck and L. Reuteri isolated from Shush native hen (Plr10), 6) Basic ration + 1.36×109 CFU/g L. Reuteri isolated from Oshnavieh native hen and L. salivarius isolated from Mazandaran native duck and L. Reuteri isolated from Shush native hen and L. Reuteri isolated from Shaft native hen (Plr11) and 7) Basic ration + 1.36×109 CFU/g L. Reuteri isolated from Oshnavieh native hen and L. salivarius isolated from Mazandaran native duck and L. Reuteri isolated from Shush native hen and L. Reuteri isolated from Shaft native hen and L. Reuteri isolated from Masal native hen (Plr12). There were no significant differences in feed intake, daily weight gain, or feed conversion ratio among the probiotic treatment groups. However, evaluation of antibody production against sheep red blood cells (SRBC) injected during the first 30 days of rearing showed that the Plr12 probiotic combination significantly increased IgG levels compared to the control group (without additives). The secondary immune response, measured 42 days after SRBC injection, showed an even greater increase in antibody levels. Additionally, all probiotic combinations significantly enhanced antibody levels compared to the control. It appears that as the chicks mature, their immune system continues to develop, and the memory cells generated during the initial immune response led to an increased production of antibodies during the subsequent response. Results derived from the broilers jejunum morphology study in the first experiment showed that the addition of the native probiotic combination Plr9, Plr11, and Plr12 to the diet resulted in a significant increase in the length of the intestinal villi of jejunum in chickens from the experimental groups when compared to chickens from the control group. Also, investigation of villus length/crypt depth and surface villus area indicated a significant increase in these traits in all probiotic treatments used compared to control treatments and commercial probiotic. The examination of the lactobacillus population in the cecal contents of broiler chickens showed that the combination of strains Plr9, Plr11, and Plr12 significantly increased the population of these beneficial bacteria compared to the control and commercial probiotic treatments. Each strain had specific probiotic properties. When these strains were combined and administered to broiler chickens, there was a significant increase in beneficial bacteria and a reduction in harmful bacteria. This study demonstrates that probiotic bacteria, isolated from the microbial population of the digestive system of native birds, have the potential to serve as valuable dietary supplements in poultry nutrition. Each probiotic strain confers varying levels of optimal efficacy; as a result, these probiotics can be used individually or in combination, and they can replace antibiotics and commercial probiotics.

This study aimed to investigate the effects of human resource training on improving production index of broiler farms in Ardabil province. Initially, out of 418 active broiler farms, the status of 50 farms was examined at the provincial level. The production units were divided into the following groups based on production index and using cluster analysis: group 1 (production index equivalent to 250), group 2 (production index less than 250 and greater than 200), group 3 (production index less than 275 and greater than 250), group 4 (production index less than 300 and greater than 275), and group 5 (production index greater than 300). Subsequently, these groups were trained in both face-to-face and non-face-to-face formats during the production period. In this process, factors affecting production index were also evaluated, and existing issues were examined in each trained farm. Finally, the obtained data were compared with the current conditions using paired t-test. The results of this study indicated that in groups with production index less than 250, training significantly increased feed conversion ratio by 7% and production index by 14% (p<0.05). However, in the group with a production index above 300, a less significant impact was observed on slaughter weight and production index (p<0.05). Overall, human resource training had a greater effectiveness in improving production index in low-performing units.

The lack of vitamins and minerals, which are lost due to processing, in poultry feed is an important challenge for poultry breeding experts. These nutrients and bioactive substances must be preserved in the feed. Protection of nutrients and vitamins in nano form is one of the most effective ways for health and prevention of diseases in poultry. Folic acid (vitamin B9) is a cofactor of many enzymes, and improper storage conditions or heat from cooking is a factor of its destruction. Due to its antioxidant properties, folic acid oxidizes quickly and has a short shelf life. However, folic acid fortification is the most efficient means of increasing dietary folate intake due to the low intake of folate-rich foods and the excessive loss of folate during processing. Therefore, it is very important to protect this vitamin in the diet. Existing methods to protect nutrients or active ingredients include microencapsulation, spray drying, extrusion encapsulation, fluidized bed coating, conjugation, nanoliposome, and hydrogel encapsulation. Nowadays, the increasing growth of new technologies (nanotechnology) as one of the important sciences in this era, has entered all dimensions and fields of animal, plant, and environmental life and has opened new horizons on the edge of natural sciences. All the physicochemical properties of the material change by changing particle size from micrometer to nanometer (one billionth of a meter) due to the increase in the surface-to-volume ratio. One of the most important methods available to preserve nutrients is the nanoliposome method. Nanoliposomes can usually range from tens of nanometers to several microns. Therefore, this research aimed to investigate the effect of folic acid nanoliposome and folic acid on blood biochemical metabolites and microbial population in the ileum of Ras 308 male broiler chickens.

This study was conducted as a 2 × 2 factorial experiment in a completely randomized design with 250 one-day-old broiler chicks in five treatments with five replicates and 10 observations per replicate. The treatments were a control diet, a folic acid-free diet supplemented with folic acid (4 mg/L of water) in non-nano form, a folic acid-fre diet supplemented with folic acid (4 mg/L of water) in nano form, a control diet supplemented with folic acid (4 mg/L of water) in non-nano form, and a control diet supplemented with folic acid (4 mg/L of water) in nano form. Carcass characteristics, malondialdehyde (MDA) concentration, and bird performance were periodically evaluated during the experiment.

Folic acid and nanoliposome folic acid did not significantly affect feed intake, weight gain, and feed conversion ratio (FCR) in the initial period. However, weight gain significantly influenced the interaction effects of folic acid and nanoliposome folic acid compared to the control diet. The addition of folic acid during the growth period significantly increased the weight of broiler chickens (p < 0.05), with a greater increase in folic acid nanoliposome treatment than in the other treatments. The interaction effects of folic acid and folic acid nanoliposome in the growing and finishing periods were significant on feed intake, weight gain, and FCR (p < 0.05). In the growing and final periods, feed intake, weight gain, and FCR increased significantly in the folic acid-free control diet in water (4 mg/L) in the folic acid nanoliposome form compared to the other treatments (p < 0.05). The lowest feed intake, weight gain, and FCR were measured in the control treatment in the growth and final periods compare d to the other treatments. Breast weight increased significantly in the control diet treatment with folic acid in water (4 mg/L) in the folic acid nanoliposome form (p < 0.05). The effect of folic acid was significant on some biochemical parameters, such as protein, albumin, and globulin, compared to the control treatment (p < 0.05). However, nano folic acid significantly increased protein, albumin, globulin, and uric acid (p < 0.05). Therefore, the highest significant amounts of total serum protein, albumin, and globulin belonged to the control diet treatment with the nano form folic acid in water (4 mg/L) (p < 0.05). Cholesterol and glucose concentrations significantly affected the interaction effects of folic acid and folic acid nanoliposome compared to the control diet. Abdominal fat and triglyceride decreased significantly in the control diet treatment with folic acid in water (4 mg/L) in the folic acid nanoliposome form (p < 0.05). However, the highest percentage of abdominal fat and triglycerides were observed in the control treatment. Although normal folic acid and folic acid nanoliposome and their interactions did not significantly influence MDA concentration,, folic acid nanoliposome positively affected the average MDA concentration. Normal folic acid and folic acid nanoliposomes did not significantly affect the microbial population of the ileum.

The results of this study showed that encapsulating folic acid in the growth and final periods improved performance, increased breast weight, and decreased abdominal fat.

Recently, the inclusion of phytogenic feed additives in poultry for the purpose of supplementing gut health and positively impacting performance has received a great deal of attention and concern. Thyme is used in poultry nutrition in the form of herbal feed additive as it is known that its contents, such as thymol and carvacrol, have a positive impact on broiler performance and feed utilization, which in turn results in enhanced economic profits. This improvement in performance can be attributed to activation of the digestive system structure and function which causes an enhanced absorption and metabolism of the nutrient supplement and its ability to alter the gut microbiota.  Formulating diets based on ideal protein concept aim to reduce total N-excretions and ammonia emissionswhile meeting the nutritional needs of the animals. Poultry needs a specific quantity and balance of essential amino acids and nitrogen (for synthesis non-essential amino acids, NEAA) rather than crude protein. Chickens fed the standard levels of dietary protein can synthesize NEAA from excess essential amino acids. However, when low-protein diets are used, less EAA is available for NEAA synthesis. Reducing dietary protein in broiler feed is not a new subject. However, it is revealed that only few trials covered an entire production cycle with several feeding phases while majority of experiments focused on one phase only. Thyme improve protein afficiency

in this experiment, the effect two levels of Zataria multifolra (0 and 0.5 %) and two protein levels (100 (CP100) and 95 (CP95) % of Ross-308 broiler chickens’ requirement) on growth performance, physiological responses and meat quality were studied. In a completely randomized design with 2×2 factorial arrangement, 280 Ross-308 broiler chickens (one-d-old, mixed sexes) were allocated to 4 treatments, 5 replicates and 14 birds in each replicate. Growth performance, immune response, blood metabolites, blood cell count, meat quality and jejunum morphometry were considered.

Feed intake, BW and FCR of finisher and total period of production, carcass parameters except abdominal fat percentage were not affected by thyme poweder, protein levels or their interaction (P > 0.05) while inclusion of thyme powder on CP100 diet improved BW and BWG of broiler chickens during starter and grower periods (P<0.05). Inclusion of thyme powder on CP95 diet decreased serum cholesterol and LDL-cholesterol and increased HDL concentration. Feeding CP95 diet contatining 0.5 thyme poweder led to increase total protein concentration and decreased liver enzymes activity (P < 0.05). Also, feeding CP95 diet containing thyme powder decreased heterophile but increased lymphocyte count (P<0.05). Dietary treatments had no significant effects on humoral immune response, relative weight of lymphoid organs, breast and thigh meat pH and color, and jejunum morphometry.

In conclusion, apart from addition of thyme powder, 5 percent protein dilution in this experiment had no negative effects on growth performance, immune response and meat quality of broiler chickens and it maybe suggestible for broiler chickens.

The use of growth-promoting antibiotic substitutes in commercial broiler farming is mainly due to the development of resistant bacteria. The use of growth-promoting antibiotics in mother hens may have important consequences, one of these effects being the reduction of the effect of antibiotics in the offspring whose parents received these antibiotics (McDonald 1995, Ghasemian and Jahanian 2016). One of the proposed alternatives to growth-promoting antibiotics are prebiotics, which include non-starch polysaccharides that are not digested in the digestive system, including fructo-oligosaccharides, galactoligosaccharides, beta-glucan, mannan oligosaccharides, etc. The main components of the yeast wall are beta-glucans and mannan oligosaccharides. which are of special importance in feeding broiler breeders because it not only changes the intestinal microflora for the benefit of the animal, but also has properties to modulate the immune system (Arsi et al. 2015). The use of cell wall yeast promotes the growth of beneficial bacteria throughout the digestive tract. Among the different probiotic species, lactobacilli and bifidobacteria use the yeast cell wall the most and grow the most when it is used (Liu et al. 2018) and also have a greater contribution to poultry health (baurhoo 2007b). Increasing the number of useful cells in the intestine reduces the number of harmful bacteria. On the other hand, the mannan present in the yeast cell wall reduces the binding of Gram-negative bacterial pathogens such as salmonella and E-coli to the intestinal epithelial cells by binding type one fimbriae. Bacteria colonize the intestine without attachment and colonization, and it is directly related to the strengthening of the animal's immune system (baurhoo 2007b). It has also been reported that the mannan fraction present in the yeast cell wall has anti-adhesion activity against Campylobacter jejuni (Ramirez-Hernandez et al., 2015; Corrigan et al., 2017).

In order to investigate the effect of different cell wall yeast levels of Saccharomyces cerevisiae in feeding broiler breeders, cell wall yeast product was prepared from Chitika Company. For this purpose, 100 broiler breeder and 25 broiler roosters (Ross 308) 54 week olds were prepared and randomly distributed in 5 treatments and 5 replications with 25 experimental units (4 broiler breeder and one rooster in each unit). The experimental treatments included 1- the control treatment (without Saccharomyces cerevisiae yeast cell wall) and treatments 2 to 5 containing 0.5, 1, 1.5 and 2 g/kg of Saccharomyces cerevisiae yeast cell wall in feed respectively. The duration of the experiment was 12 weeks, which was divided into 3 periods (age 54-57, 58-61, and 62-65 weeks), and the birds had free access to water and food during the entire experiment. Room temperature, lighting duration and other management items were based on the standard of the strain guide (birds had the same amount of feed). The experiment was divided into three periods of four weeks according to the different stages of the birds' production, and for this purpose, at the end of the 4th, 8th and 12th weeks, the birds were weighed and the average weight of each group was reported. The eggs of all experimental treatments were counted and collected separately in the whole period. In order to determine production performance, production percentage and average egg weight were measured and calculated daily in the entire period and the results were reported. In order to check the quality characteristics of eggs, at the end of the 8th and 12th week, 2 eggs were randomly selected and evaluated from each replication, and the average of these two weeks was reported in the results of this study. The resistance of the egg shell was measured using a Japanese resistance measuring device with specifications (Co., Ltd., Tokyo, Japan Robotmation) in which the eggs were placed vertically and the egg cracked due to the applied force and the applied force It was measured in kilograms per square centimeter.

The experimental treatments had no significant effect on the weight changes of broiler breeders. The results showed that the experimental treatments had significant effects on the percentage of egg production in all three test periods. In the first period of the experiment, the group fed with 1.5 and 2 g/kg with 63.97 and 63.54 percent egg production had a significant difference compared to the control group which had 62.35 percent production. In the second period (age 58-61 weeks), the group fed with one g/kg of Saccharomyces cerevisiae yeast had a significantly higher percentage of egg production than the control group. In the third period, the groups receiving Saccharomyces cerevisiae yeast had a significantly higher percentage of egg production than the control group. Different levels of Saccharomyces cerevisiae yeast did not have a significant effect on shell resistance and thickness in broiler breeders compared to the control group. The test results show the effect of treatments containing 1, 1.5 and 2 g/kg of Saccharomyces cerevisiae cell wall causing a significant reduction in the number of broken eggs. The use of levels of 1, 1.5 and 2 g/kg of cell wall yeast in the diet caused a significant increase in the antibody titer of Gambro virus in broiler breeders during the experimental period.

The results of this study showed that in the three defined experimental periods of 54-57, 58-61 and 62-65 weeks, experimental treatments had no significant effect on body weight changes. Treatments containing 0.5, 1, 1.5 and 2 g/kg of Saccharomyces cerevisiae wall yeast significantly increased the percentage of eggs produced compared to the control group, as well as the effects of decreased production due to aging in the feeding groups. It was less with yeast cell wall. Experimental treatments had no effect on average egg weight, egg resistance and shell thickness. The percentage of deformed and broken eggs in the groups receiving 1, 1.5 and 2 g/kg of cell wall yeast significantly decreased compared to the control group. In general, according to the results obtained from this research, it can be said that the use of commercial yeast Saccharomyces cerevisiae has favorable effects and also the best level used is 1 g/kg of feed.

Manganese is an essential trace element that acts as an activating component of many crucial enzymes such as alginase and pyruvate carboxylase. It is involved in carbohydrate, lipid, and protein metabolism, as well as in vital biochemical reactions (Hassan et al., 2020). Additionally, manganese serves as a cofactor in the synthesis of chondroitin sulfate and plays a significant role in bone formation in broiler chickens (Mwangi et al., 2019). Moreover, manganese is vital for the antioxidant and immune systems of animals (Patra and Lalhriatpuii, 2020; Wang et al., 2018). In the production of broiler chickens, manganese sources commonly used include inorganic Mn (Mn sulfate, Mn carbonate and Mn oxide) and organic Mn (Mn chelated with amino acid and protein). Inorganic sources of manganese are cheaper, although they have low digestibility (Tufarelli and Laudadio, 2017; Yenice et al., 2015). Organic sources have excellent chemical stability and high absorption efficiency. They have not been widely used in poultry diet due to different quality levels of manufactured products, unpredictable effects and high cost (Tufarelli and Laudadio, 2017; Brooks et al., 2012). Therefore, it is important to assess new sources of manganese that have higher digestibility and lower cost. Manganese hydroxychloride is a group of minerals which solubility in water is minimal, but it becomes more soluble in acidic conditions in intestine (Wang et al., 2011). The purpose of this experiment was to investigate the different levels and sources of manganese in the diet of broiler chickens by investigating their effects on growth performance, immunity, the digestibility of different sources in different solvents, and the digestibility using the technique of Everted Gut Sacs. Manganese sulfate, organic manganese, and manganese Hydroxychloride were obtained from Ariana company. In order to measurement of the amount of dry matter and ash, one gram in four repetitions was sampled from each of the sources. They were dried at 105°C for 12 hours and dry matter was calculated through subtraction. Then samples were transferred to the oven at 550°C for 16 hours and their ash content was determined. Finally, they were digested in hydrochloric acid and passed through Whatman filter paper No. 42. After making up to volume with mili-Q water, they were read by an atomic absorption device at a wavelength of 520 to 560 nm (AOAC, 1995; Williams, 1972). In order to evaluate the solubility, three samples (0.1 g) were prepared and dissolved in 100 ml of 2% citric acid, 0.4% hydrochloric acid and deionized water (Watson et al., 1970). For assessment ability to absorb minerals by the technique of Everted Gut Sacs, 180 one-day-old broilers of the Ross 308 commercial strain were fed from one to twenty-one days old with corn and soybean based (2018). On the 22nd day to the 28th day, they were fed with a diet free of manganese and on 29th day, they were starved for one day and night. Chickens were grouped into three treatments with Hydroxychloride, organic and manganese sulfate sources with 6 replications and 10 pieces per replication. Three parts were selected from each replication for the test steps (Feng et al., 2006). Samples prepared from jejunum and ileum in two buffers, Mis-Krebs and Tris-Krebs. In order to determine the relative bioavailability of different manganese sources, an experiment was conducted with 12 treatments included four different levels of manganese (35, 70, 105 and 140 mg/kg) with three different sources including Hydroxychloride, organic and sulfate. The highest amount of dry matter of manganese was related to manganese sulfate (99.23%). The lowest was manganese hydroxychloride (92.58%). The highest ash percentage was related to manganese hydroxychloride with 86.14% and the lowest was related to organic manganese with 21.56%. The amount of manganese calculated after testing organic sources, hydroxychloride and sulfate was 5.64, 34.64 and 34.47% respectively. The organic form of manganese had the highest solubility in 2% citric acid and the lowest in deionized water with 96.12 and 34.14%, respectively. Manganese hydroxychloride also had the highest solubility in 2% citric acid solution. Manganese sulfate had the highest solubility in hydrochloric acid and the lowest solubility in deionized water. In general, manganese sulfate had the highest solubility in deionized water compared to the other two sources. Also, the highest solubility of organic manganese in 2% citric acid was 96.12% in the whole experiment. It has been reported in studies that binding minerals with proteins will be a weak chelate and when they are placed in solvents, their chelate breaks easily and dissolve (Cao et al., 2000). The results related to performance traits and primary and secondary response of antibody titer against sheep red blood cells (SRBC) showed that experimental treatments had no significant effect on them.  The results showed that the highest solubility of the organic form of manganese was in citric acid (96.12%) and the lowest was in deionized water (34.13%). Manganese hydroxychloride had the highest solubility in 2% citric acid, while manganese sulfate had the highest solubility in 0.4% hydrochloric acid. Overall, manganese exhibited the highest solubility in hydrochloric acid and the lowest in deionized water. The results of the technique of inverted intestinal segments showed that the most absorption of manganese occurs in the ileum, and these results were in line with the results of other researchers who had performed this experiment in vitro and in vivo Among the experimental treatments, the highest absorption in the technique of inverted intestinal segments was related to the organic source of manganese, and the lowest was related to the form of sulfate, 3.25% and 1.99%, respectively. At the end, the use of organic manganese in broiler diet is recommended due to its high absorption level.

This study was conducted to investigate the effect of different levels of alkaline hydrolyzed feather meal (AHFM) on the performance, intestinal morphology, and meat oxidation of Arian broiler chickens from d 15 to 42. A total of 480 one-day-old chickens of two sexes (equal ratio) were randomly distributed among 24 pens (20 chicks per experimental unit). The four experimental diets contained different levels of feather meal (0, 2, 4, and 5 %), which were replicated six times. During the grower period, daily weight gain decreased and the feed conversion ratio increased at 4 and 5 % AHFM levels (P<0.05), also feed intake increased in birds fed on a 5 % AHFM diet (P<0.05). In the overall experimental period feeding 4 % AHFM decreased the body weight gain compared to control (P<0.05) and the feed intake was reduced in birds fed on 2 % AHFM (P<0.05). The feed conversion ratio has not been influenced by the level of AHFM 15-42 d. Diets with AHFM decreased the jejunum villi height, while this reduction in the ileum was observed at 4 and 5 % AHFM, and goblet cell density increased at 5 % AHFM (P<0.05). With the increase in the level of AHFM, the concentration of malondialdehyde in fresh breast, and thigh meat decreased so that the group receiving five percent of AHFM had the lowest concentration of malondialdehyde (P<0.01). The level of 5 % AHFM reduced the litter moisture (P<0.05) and the levels of AHFM did not affect the concentration of the litter ammonia. None of the mortality, production efficiency index, and feed cost per kilogram of live weight were significantly affected by experimental treatments. As a general conclusion, the use of AHFM reduced the body weight and increased the feed conversion ratio of Arian broilers without affecting the mortality rate and production efficiency index, although meat oxidative stability improved.

During the last stages of incubation, avian mortality commonly happens due to the lack of enough nutrients and amino acids (Fardoost et al. 2019). However, in ovo injection or in ovo feeding is considered a new technique for improving growth of chickens (Ebrahimi et al. 2017). Most studies indicated improving effect of in ovo feeding of nutrients (especially amino acids) on small intestine growth and histology as well as higher absorptive capacity of digestive system (Ebrahimi et al. 2017, 2018a,b; Elwan et al. 2019; Fardoost et al. 2019). Previous studies indicated an improving effect of excess feeding of arginine on growth performance, carcass traits, blood metabolites, and intestinal histology of broilers (Ebrahimi et al. 2013, 2014, 2016b). However, there are few records regarding the impact of in ovo injection of arginine on intestine histology of chickens. Accordingly, the present study was designed to evaluate the effect of in ovo injection of different levels of arginine on carcass traits, blood metabolites, and small intestine histology of broiler chickens.

For this reason, 300 fertile broiler breeder eggs were divided into three treatment groups: 1- 0.5% L-arginine in ovo injection group (100 eggs), 2- 1% L-arginine in ovo injection group (100 eggs), 3- control group included distilled water injected (sham-control subgroup, 50 eggs) and non-injected (control subgroup, 50 eggs). Eggs were then set into the incubator for the first 18 days with the temperature of 37.8°C and six rotations per day. At d 14 of incubation, eggs were injected into the amniotic fluid (Ebrahimi et al. 2017) as follows: 1- in ovo injection of 5 mg L-arginine/ ml distilled water, 2- in ovo injection of 10 mg of L-arginine/ml distilled water, 3- control group included sham-control (in ovo injection of 1 ml distilled water) and control (received no injection). For in ovo injection, solution pH was set at 7.0. At d 18 of incubation, eggs were moved into hatchery boxes. After hatching, chicks were reared for 24 days. During the experiment, chicks received standard commercial diets based on Ross recommendations as starter (0-10 days) and grower (11-24 days), (Table 1). At d 24, blood samples of three chickens per each replicate were collected, centrifuged (3000 rpm for 20 minutes), and serum was separated to evaluate cholesterol, glucose, triglyceride, uric acid, and total protein by the Enzymatic Colorimetric method (Ebrahimi et al. 2017). Then, all birds were weighed, slaughtered, some carcass traits (scalped carcass, eviscerated carcass, breast, thigh, gizzard, proventriculus, pancreas liver without gall bladder, heart, duodenum , jejunum, and ileum were weighed, and their relative weight to chicken body weight were calculated. Also, length of duodenum , jejunum, and ileum was evaluated and their samples were stored in 10% formalin for fixation to evaluate histological parameters (crypt depth, villus height, villus thickness, mucosal thickness, and crypt diameter) using Hematoxylin - Eosin staining method (Ebrahimi et al. 2017). Then, villus height to crypt depth ratios were calculated. Afterwards, data were analyzed based on a completely randomized design by the Proc GLM of SAS software (Ver 9.2). Also, Tukey-Kramer test was used for comparing treatments and results presented as least square means ± standard error.

Based on the results, in ovo injection of different levels of L-arginine did not affect hatchability, day-old chick weight, chick weight to egg weight ratio, 24-day-old chicken weight, feed conversion ratio, relative weight of all carcass traits, cholesterol, glucose, total protein and blood urea nitrogen (P> 0.05), (Table 2). However, serum triglyceride was significantly affected by experimental treatments (P <0.01) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 2). In a similar study, Gao et al. (2017) indicated that L- arginine in ovo injection increased weight gain of broiler chickens. Furthermore, Abdolalizadeh Alvanegh et al. (2017) reported the improving effect of in ovo injection of different ratios of L- arginine to L- lysine on chick weight and their carcass traits. Also, they reported higher serum total protein level, while lower blood urea nitrogen of broiler chicks with in ovo injection of different ratios of L- arginine to L- lysine (Abdolalizadeh Alvanegh et al., 2017).Present results indicated no significant effect of in ovo injection of L-arginine on most weight and length parameters of small intestine length (P>0.05); however, relative weight of jejunum was significantly affected by in ovo injection of L-arginine (P<0.05) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 3). Present results indicated no significant effect of in ovo injection of L-arginine on duodenal crypt diameter; jejunal villus height, crypt depth and diameter, and mucosal thickness; and ileum villus height, crypt depth, villus height/crypt depth ratio, and mucosal thickness (P>0.05), (Table 3). However, significant effect of in ovo injection of L-arginine was observed on duodenal villus height, villus thickness, crypt depth, villus height/crypt depth ratio, and mucosal thickness; jejunal villus thickness and villus height/crypt depth ratio; and ilium villus thickness and crypt diameter (P<0.05), (Table 3). Also, the highest amount in most histological parameters was observed in 1% arginine treatment (Table 3). In a similar study, it was reported that in ovo injection of L- methionine had a positive impact on small intestine length and weight with improvement in villus height, crypt diameter, crypt depth, and villus height/crypt depth ratio of duodenum and jejunum (Fardoost et al. 2019). Also, in ovo injections of L- lysine improved histological parameters of duodenum, jejunum, and ileum (Ebrahimi et al. 2017). Ebrahimi et al. (2018b) with in ovo injection of different DL- methionine to L- lysine ratios reported higher small intestinal weight and length along with higher Villus height and Villus height to crypt depth ratio.

Based on the overall results of the study, injection of 0.5% arginine showed a positive effect on the growth and small intestine morphology of broiler chickens.

In recent years, consideration has been given to changing the sex of a female bird to male because it has the functional characteristics of the male phenotype, and the technique of in ovo injection is used to achieve this. For this purpose, the production process of some sex hormones in broiler chickens is changed by injecting a substance containing anti-aromatase. The aromatase enzyme (Arom P450) is considered a key enzyme in estrogen synthesis. The administration of aromatase inhibitors leads to the inhibition of estrogen synthesis (a hormone responsible for ovarian structure and secondary sexual characteristics) in females and the production of males with female genotypes. Therefore, if aromatase enzyme expression is inhibited in some way, it can be expected that the percentage of male chicken production will increase. Aromatase inhibitors can be divided into two main groups in terms of production source, including synthesized and herbal compounds. Among the herbal extracts containing anti-aromatase are nettle root, button mushroom, garlic, green tea, and tomato. On the other hand, the results of some studies have shown that the performance indicators of male and female poultry during the breeding period, such as daily feed intake (DFI), daily weight gain (DWG), feed conversion ratio (FCR), as well as the activity of the digestive system, especially the small intestine, are different and the ability to use nutrients, growth rate and FCR are better in males than females. According to male poultry characteristics, if the number of males in the flock increases, more profitability can be achieved in the production process. Therefore, the objectives of the current study were to determine the effects of in ovo injection of nettle extract, mushroom extract, and their mixture on hatched chickens, performance, and intestinal indicators of Ross 308 broiler chickens. This study was conducted to investigate the in ovo injection effects of nettle and mushroom extracts, and their mixture on hatchability, the percentage of male chickens produced, and some intestinal parameters in broilers. 500 fertilized eggs were divided into five treatments and four replicates (25 eggs per replicate). Experimental treatments included: 1. Nettle hydroalcoholic extract (containing 300 micrograms of dry matter per 0.1 cc of injectable substance), 2. Mushroom hydroalcoholic extract (containing 500 micrograms of dry matter per 0.1 cc of injectable substance), 3. Mushroom and nettle extracts mixture (containing 400 micrograms of dry matter per 0.1 cc of injectable substance), 4. Positive control (distilled water), and 5. Negative control (eggs without any injection). The experimental design was a completely randomized block design. Samples were divided into five treatment groups, with each treatment group having four replications based on the gender segregation of the chicks into male and female. The experimental diet was used based on the requirements of the Ross strain during three periods, including starter, grower, and finisher. After the chickens were hatched, performance and intestinal indices were measured. The results showed that the number of hatched chicks was affected by experimental treatments. Therefore, the lowest hatch percentage was related to URE treatment chicks. The number of normally hatched male chickens, performance indices, and intestinal parameters were not affected by the experimental treatments (P>0.05). The lack of significant difference in the number of male chickens in the experimental treatments may be due to the incorrect selection of the concentration of the experimental extract. Furthermore, villi height, crypt width, and villi surface absorption area were not affected by experimental treatment (herbal extracts). In comparison, DWG and FCR significantly improved by the sex effect (P<0.05). Regarding the difference in the performance of male and female broiler chickens, it has been reported that these two sexes have a significant difference in DFI and FCR. It has also been reported that the increase in BWG and the weight of different parts of the carcass in males was higher than in females, which is consistent with the findings of the current research regarding all three indicators of DFI, DWG, and FCR. Although there was no significant increase in the number of hatched male chickens in this study, it is recommended to optimize the preparation and production conditions of plant extracts containing anti-aromatase by focusing on extracting the pure active ingredient to achieve a higher percentage of male chickens in the flock. This study was conducted to investigate the in-ovo injection effects of nettle and mushroom extracts and their mixture on hatchability, the percentage of male chickens produced and some intestinal parameters in broilers. 500 fertilized eggs were divided into 5 treatments and 4 replications (25 eggs per replication) in a completely randomized design. Experimental treatments consisted: 500 fertilized eggs were divided into 5 treatments and 4 replicates (25 eggs per replicate) in a completely randomized design. Experimental treatments consisted: 1- nettle hydroalcoholic extract (containing 300 micrograms of dry matter per 0.1 cc of Injectable substance), 2- mushroom hydroalcoholic extract (containing 500 micrograms of dry matter per 0.1 cc of Injectable substance), 3- mushroom and nettle extracts mixture (containing 400 micrograms of dry matter per 0.1 cc of Injectable substance), 4- positive control (distilled water) and 5- negative control (eggs without any injection). The experimental diet was used based on the requirements of the Ross strain during three periods, including starter, grower and finisher. After the chicken were hatched, performance and intestinal indices were measured. The results showed that the number of hatched chicks were affected by experimental treatment. So that, the lowest hatch percentage was related to URE treatment chicks. The number of normal hatched male chicken, periodic performance indices and intestinal parameters were not affected by the experimental treatments (P>0.05). The lack of significant difference in the number of male chicken in the experimental treatments may be due to the incorrect selection of the concentration of the experimental extract. Furthermore, villi heigh, crypt width and villi surface absorption area(VSA) were not affected by experimental treatment (herbal extracts). In comparison, DWG and FCR significantly improved by the sex effect (P<0.05). Regarding the difference in the performance of male and female broiler chicken, it has been reported that these two sexes have a significant difference in DFI and FCR. It has also been reported that the increase in BWG and the weight of different parts of the carcass in males was higher than females, which is consistent with the findings of the current research regarding all three indicators of DFI and DWG as well as the FCR. Although there was no significant increase in the number of hatched male chickens in this study, it is recommended to optimize the preparation and production conditions of plant extracts containing anti-aromatase by focusing on extracting the pure active ingredient to achieve a higher percentage of male chickens in the flock.Key words: nettle and mushroom extract, ant i-aromatase, broiler chicken, plant extract, in-ovo injection

Vitamins play an important role in improving the performance, immune system, and growth of birds. In recent years, due to the increase of the price of synthetic vitamin supplements and also due to the limitation of the use of commercial antioxidants, plant-based antioxidant sources have been considered in the poultry industry. Therefore, this study aimed to investigate the effects of herbal vitamin E supplements on production traits, humoral immune responses, and some blood parameters of broiler chickens.

In a completely randomized design 480 Arian broiler chickens (one-day-old, mixed sexes) were allocated to four treatments, four replicates, and 30 birds in each replicate. Experimental treatments included: 1. basal diet (Contains 25 IU of synthetic vitamin E), 2. basal diet + 25 IU synthetic vitamin E, 3. basal diet + 50 mg herbal vitamin E supplement, and 4. basal diet + 100 mg herbal vitamin E Supplement. In this experiment, weight gain, feed intake, and feed conversion ratio (FCR) were measured. On day 40, two birds per replicate were randomly selected, weighed, and killed, and then the entire empty carcass and parts of the carcass including breast, thigh, neck back, and wings, abdominal fat, and some organs including heart and spleen were weighed. One day 40 days, to measure the concentration of total protein, albumin, triglyceride, cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and the activity of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase enzymes, blood was collected from each replicate of 4 birds. On day 33 to measure antibody titer against Newcastle disease and influenza, 1 ml SRBC was injected into 4 birds in each repetition.

  The results showed that the experimental treatments had no effects on feed intake, body weight, and FCR. Also, carcass characteristics including carcass percentage, breast, thigh, back, and neck percentage, abdominal fat, heart, spleen, and blood parameters were not affected by experimental treatments. Antibody titer against sheep red blood cell injection had no significant effect.

In total, according to the recommendation of commercial strains, the requirement of vitamin E is 50 IU, therefore in case of providing 25 IU of synthetic vitamin E in the diet, it is possible to provide the rest of the need up to 50 IU by using the herbal vitamin E supplement (at the rate of 50 mg per kilogram of feed) considering there are economic considerations.

With the increase of the population in the last century, the need for protein sources, especially protein with animal origin, has increased. One of the important and inexpensive sources of animal proteins is poultry products. However, many food-borne diseases that are among the most obvious problems related to human health are transmitted to humans through poultry products. Generally, poultry are sensitive to pathogenic bacteria such as Clostridium, Salmonella, and Campylobacter. Campylobacter jejuni and Campylobacter coli are the main causes of bacterial enteritis in humans and account for about 90% and less than 10% of deaths in people with campylobacteriosis, respectively. Poultry farmers use antibiotic growth promoters to prevent the colonization of pathogenic bacteria, but their use has been banned in European Union since 2006 due to antibiotic resistance. However, in order to prevent the reduction of growth performance and mortality caused by the colonization of pathogenic bacteria in the gastrointestinal tract, it is necessary to introduce suitable alternatives. The antimicrobial potential of several medicinal plants, some plant-derived bioactive compoundsas well as some organic acids against a suspension of two Campylobacter serotypes (including 8 strains of C. jejuni and 3 strains of C. coli) has been investigated, under in vitro study. It has been revealed that oregano, rosemary, and cinnamon have a higher potential in reducing campylobacter colonization, among other phytobiotic compounds. Considering that under in vivo conditions, no research has been conducted on these medicinal plants with broiler chickens exposed to Campylobacter colonization. Therefore, this research was conducted with the aim of investigating the growth performance, excreta microbiota, intestinal morphology, and nutrient digestibility of broiler chickens challenged with C. jejuni and evaluating the potential of oregano, rosemary, and cinnamon in reducing the negative effects of this pathogen.

A total of 192 one-day-old chicks were randomly allocated to 6 dietary treatments in a completely randomized design with 4 replicates of 8 birds. The dietary treatments were as follows: 1-negative control (NC; basal diet without additive and without of C. jejuni); 2-positive control (PC; basal diet without additives but challenged with C. jejuni); 3-basal diet + Erythromycin (55 mg/kg); 4-basal diet + oregano powder (3 g/kg); 5- basal diet + rosemary powder (3 g/kg) and 6-basal diet+cinnamon powder (3 g/kg). All chickens were orally gavaged once a day with a suspension of C. jejuni live culture (2×108 cfu/mL, 1 mL/bird) on days 21 to 25, with the exception of those fed the NC. Throughout the experimental period, the birds were fed ad libitum and had free access to water.

The results showed that the C. jejuni, while weakening performance during the growth period, caused an increase in campylobacter colonization and a decrease in lactobacilli counts of the excreta (P<0.05). The reason for the improvement of the microflora can be due to the presence of antibacterial compounds such as thymol, carvacrol, verbenone, and cinnamaldehyde in the composition of the mentioned medicinal plants. Campylobacter jejuni also decreased the digestibility of organic matter and led to a decrease in villous height, villous height to crypt depth ratio, and villi surface area in the jejunum (P<0.05). The reason for the improvement of the intestinal morphology by herbal additives can be due to the improvement of the microflora of the digestive tract. All the negative effects arising from C. jejuni were alleviated by dietary treatments containing feed additives (P<0.05).

In general, it can be concluded that oregano and rosemary have the potential to reduce the pathogenic effects of Campylobacter jejuni and can be used as suitable alternatives to antibiotics in feeding broilers.

During the winter months in most parts of Iran, the external temperature often drops below 0 °C. Typically, these temperatures fall below the optimal conditions for chick growth, resulting in cold stress and potential diseases. This can subsequently impact meat quality negatively and reduce breeding efficiency. The environmental temperature beyond the upper and lower limit of the thermoneutral zone is supposed to produce heat or cold stress in animals (Meltzer, 1983). The adverse climatic condition produces physiological stress which has profound economic influence on the productive efficiency including health and disease resistant capacity (Phuong et al., 2016). Exposure of poultry birds to extreme temperature stressor modulates the immune responsiveness and hematic-biochemical parameters of birds (Hangalapura et al., 2004). Among all the environmental stressors, cold stress induces physiological responses which are of high priority and energy demanding for homeotherms. Cold temperature can increase ascites susceptibility by increasing both metabolic oxygen requirements and pulmonary hypertension (Stolz et al., 1992). The biggest obstacle in raising broilers at high altitudes and cold conditions is the ascites syndrome. This condition can be characterized by an accumulation of fluid in the abdominal cavity and elevated mortality that tends to peak between 4-6 weeks of age (James, 2005). The International Biochar Initiative (2017) defines biochar as, “Solid material obtained from thermochemical conversion of biomass in an oxygenlimited environment.” Biochar is an ash substance that is produced from the burning of biological material via pyrolysis. This process heats the biological material in an anaerobic environment causing it to decompose into an ash form. Growth promotion and therapeutic antibiotics have been used to compensate for the high levels of stress, including cold stress,that can be present in intensive animal production. Stress can lower resistance to many of the microorganisms present in the environment; however, stress in general has been reported to have variable effects on the immune system and can both enhance and suppress responses (Siegel, 1995); cold stress has been shown to both stimulate and suppress chickens’ immune response (Regnier and Kelley, 1981; Hangalapura et al., 2006). Probiotics contain live microorganisms and spores which when administered in adequate amount, confer health benefits to the host. Bacillus subtilis (B. Subtilis) and Bacillus licheniformis (B. Licheniformis) are the two most widely used strains of probiotic bacteria in animal diets. Oral administration of B. Subtilis and B. Licheniformis can have a myriad of beneficial effects, such as improved growth and meat characteristics, optimized composition of intestinal microbiota, prevention of some diarrheal diseases, and reduced stresses. For such benefits, B. Subtilis and B. Licheniformis have attracted considerable attention as a potentially beneficial dietary supplement for animal health.  For the many negative effects of antibiotic drugs used in chick production, we want to compare the positive effects of some additives on performance of cold-stressed broiler chickens.

In this experiment, in order to examine the effect of solid waste biochar, probiotic and zeolite on improvement of performance, blood indices and small intestine morphology of broiler chickens reared under cold stress, in a completely randomized design, 315 Ross-308 broiler chickens (as hatched) were allocated to 7 treatments, 5 replicates and 9 birds in each in cold and warm houses. Treatments are including: 1) positive control (basal diet in recommended temperature), 2) negative control (basal diet + cold stress), 3-7) negative control + %0.5, %0.75 and 1% solid waste biochar, 0.02% probiotic Ecobacto-P and 1% zeolite, respectively. In cold stress groups, house temperature decreased to 17° C from 7d until end of the experiment (42d).

As compared to group reared in warm house, cold stress significantly decreased broiler chickens daily FI and BWG, serum total protein, albumin and globulin concentrations, thymus relative weight, lymphocyte percentage, breast and thigh meat pH, breast meat redness (b) and thigh meat yellowness (a) while increased total and ascitic mortality, red and white blood cell count, blood hemoglobin, heterophile percentage and heterophil to lymphocyte ratio, antibody titter against SRBC, breast and thigh meat whiteness and breast meat MDA concentration (P < 0.05).

In order to orthogonal contrast analysis between negative control group and additive groups, solid waste biochar, probiotic or zeolite couldn’t improve broiler chicken’s growth performance, breast and thigh meat quality parameters, blood metabolites concentration and cell count and did not ameliorate negative effects of cold stress.

In this experiment, the effect of two types of zinc-methionine (Zn-Met) chelate on performance and bone characteristics of broiler chickens were considered in a completely randomized design, using 490 Ross-308 broiler chickens (one-d-old, mixed sexes) with 7 treatments, 5 replicates and 14 birds in each replicate. Treatment consisted of: 1) control (basal diet), 2-4) control + 0.2, 0.4 and 0.8 mg/kg Zn-Meth of Zin-Pro® respectively and 5-7), control + 0.2, 0.4 and 0.8 mg/kg zn-Met synthetized by Ilam University. Results showed that as compared to group, none of zn-Met source had significant effect on broiler chickens feed intake, body weight, FCR and EPEF, carcass and breast and thigh percentages, serum glucose, triglyceride, cholesterol, LDL-cholesterol and HDL-cholesterol, triglyceride and Ca concentrations, activity of Alkaline phosphatase, Aspartate transaminase and Alanine aminotransferase enzymes and tibia characteristics including weight, dry matter and ash percentages, length, width and diameter and P and Ca percentages (P < 0.05) while broilers fed diet containing Zn-Meth had higher serum and tibia Zn concentration, higher villous height and villous height to crypt depth ratio and lower villous width in ileum and jejunum as compared to negative control group (P < 0.05). Generally, both of the chelates had similar effects on broiler chicken’s performance, small intestine morphology and tibia traits and Iranian kind of Zn-Meth has capability to substitution with foreign source of it although needs to further investigations.

In recent decades, with the ban on the use of antibiotics in the poultry industry, the use of new alternatives such as probiotics and prebiotics have increased. Some of these alternatives can improve the growth and health of birds by creating optimal changes in the microbial population of the digestive tract. Therefore, the present experiment was conducted to investigate the effect of kappa-carrageenan polysacharid and primalac probiotic on the growth response and health of broilers.

240 one-day-old broilers of Ross 308 strain in a completely randomized design with 2× 2 factorial arrangement, including two levels of probiotic additive (zero and 0.1 % of food ration) and two levels of kappa-carrageenan additive (zero and 0.1 % of food ration) distributed in 24 cages (six replicates each containing ten birds) and reared on floor system for 24 days.

The growth performance of birds was not affected by the interaction of probiotics and kappa-carrageenan in the diet. However, the use of kappa-carrageenan in diets significantly increased the body weight gain of birds during 1 to 10 days of age. Feed intake of the birds was not affected by the experimental treatments and dietar levels of probiotic and kappa-carrageenan, but the feed conversion ratio was improved by adding 0.1% of probiotic in the diet at day 24 (P< 0.05). The relative weight of thigh in birds that received kappa-carrageenan was higher compared to the zero level of kappa-carrageenan in the diet (P< 0.05). Probiotic supplementation alone in the diet increased the relative weight of the liver of birds. Also, the relative weight of the liver was significantly lower in the birds that received diets containing kappa-carrageenan. In broilers fed with kappa-garakinan, the villus length increased in the duodenum and decreased the crypts depth in the ileum. The use of 0.1% of probiotics significantly increased the population of lactic acid bacteria in the ileum of birds. The population of lactic acid bacteria in the ileum of birds under 0.1% of probiotic increased significantly. Consumption of kappa-carrageenan and probiotics separately or mixed in the diet reduced the population of coliforms in the cecum (P< 0.05). Using a mixture of kappa-carrageenan and probiotic in the diet the activity of superoxide desmutase enzyme improved compared to the treatment containing kappa-carrageenan (P< 0.05).

The results of the present experiment showed that the use of probiotics and kappa-carrageenan in the diet of young broiler chickens can be effective in improving some parameters of the growth response during separate periods of rearing and optimally changing the microbial population of the digestive tract.