سید داود شریفی

Optimizing the balance between metabolizable energy (ME) intake and expenditure is essential for broiler diet formulation and levels of other dietary nutrients for efficient conversion of feed into muscle mass. The Arian broiler is one of the meat breeds that originated in Iran and given that several decades have passed since the Arian line entered in the Iran; it is necessary to conduct continuous nutritional experiments to more accurately estimate their requirements in terms of improving growth, feed conversion ratio (FCR), carcass efficiency and increasing muscle mass by increasing the density of nutrients such as amino acids (AA). Therefore, the objective of this study was to investigate the effects of dietary energy and AA levels on growth performance and nutrient digestibility of Arian broilers.

The effects of dietary energy and AA levels  on growth performance and nutrient digestibility of Arian broiler chickens was investigated with a total of 720 one-day old broiler chicks in a completely randomized design with six treatments, five replicates and 24 birds per each for 42 days. The experimental treatments included T1:control diet (energy and amino acid levels throughout the breeding period accordance with the guidelines for the Arian broiler strain), T2:diet with less energy level during the starter and grower periods and then according to the Arian requairements guide until the end of the period, T3:diet with less energy and amino acid levels during the starter and grower periods and then according to the guide until the end of the period, T4:diet with less energy level during the starter and grower periods and then higher amino acid levels in the finisher period, T5:diet with less energy and amino acid levels in the starter and grower periods and then higher amino acid levels in the finisher period, T6:starter and grower period diet according to the Arian requairements guide and then higher amino acid levels in the finisher period.

The daily weight gain of birds fed T6 increased compared to T3 and T5 (P<0.05). Birds that received T6 had a higher glucose level and lower low-density lipoprotein, compared to the birds that received the control diet (P<0.05). The relative breast weight and production index of birds that were fed T6 increased compared to the birds that fed T1 and T3 (P<0.05).

The economic calculations of the design showed that it is possible to use the advantage of the energy and amino acid levels in the diet of Arian broilers. Overall, feeding a starter and grower period diet according to the Arian requairements guide and then higher amino acid levels in the finisher period which had positive effects on growth performance and economic indicators in Arian broilers, is recommended.

The effect of utilization of feed disinfected with ozone gas on performance, carcass characteristics and blood parameters of broilers was investigated using 432 Ross 308 male broilers in a 3×2 factorial arrangement with three levels of ozone gas (zero, 20, and 30 parts per million) and two levels of fat including low (1.5 and 2% vegetable oil for grower and finisher periods, respectively) and high (3 and 4% of vegetable oil for grower and finisher periods, respectively) in a completely randomized design with 6 treatments and 4 replications of 18 birds in each. At 42 days of age, two birds were selected from each replication and slaughtered after weighing and the weights of the carcass, heart, liver, small intestine, and ceca were measured precisely. The results showed that the weight gain of chicks fed a high-fat, ozone-free diet was significantly higher than that of chicks fed a high-fat, gassed with a 20 ppm ozone diet (P <0.05). The ceca weight of chicks fed low-fat diets was higher than that of birds fed high-fat diets and birds fed diets gassed with 20 ppm ozone had higher ceca weight (P <0.05). According to the results of this experiment, it seems that the utilization of ozone gas for the disinfection of diets containing high levels of fat has a negative effect on feed quality and reduces the performance of broilers.

Japanese quail has a rapid growth rate (3 to 4 generations per year) and is relatively resistant to many diseases. Due to its high productivity, it has gained importance as an animal model in biological and genetic studies worldwide. Nutrition is a key factor that affects production efficiency in quails. Japanese quails require a diet that contains high-quality protein and a balanced profile of amino acids. Branched-chain amino acids (leucine, isoleucine, and valine) not only contribute to protein synthesis but also play a role in other metabolic activities. Among the branched-chain amino acids, valine is a limiting amino acid in corn-soy-based diets. Protein is the most expensive component of the diet and has a significant impact on production costs in poultry. Nowadays, reducing the protein level in the diet has garnered attention for cost reduction in farming and for mitigating environmental pollution resulting from ammonia emissions and nitrogen excretion in the poultry industry. However, reducing the protein level in the feed without proper supplementation of amino acids can lead to decreased feed intake, reduced production levels, and changes in social behavior in birds. Published reports indicate that adding crystalline amino acids to low-protein diets in meat birds can have similar performance to high-protein diets at different growth stages. In most cases, valine becomes limiting with reduced protein levels in the diet. Considering the important metabolic roles of branched-chain amino acids, especially valine, in rapidly growing birds, the aim of this experiment was to investigate the effects of using diets containing different digestible valine levels on the performance, growth traits, and histology of the liver and magnum in Japanese quails during the growth period.

All experimental procedures for the care and use of animals in the present study were approved by the animal care committee of the University of Tehran. Thousand one-day-old quails were given 5 dietary treatments, such that each treatment was replicated 5 times and 40 birds per replicate in a completely randomized design, during 1–42 days of age. Experimental diets were formulated to meet nutrients recommendation of growing quails with different levels of dietary digestible valine concentration (0.75, 0.85, 0.95, 1.05 and 1.15 %) in diets with a low protein (17.7-17% protein). The experimental diets provided 2,9 kcal metabolizable energy per gram. Other nutrients were provided based on the recommended nutritional requirements for growing quails. Other nutrients were formulated based on the recommended nutritional requirements for growing quails. The experimental diets were adjusted for two age periods: 1-21 days and 22-42 days. The birds received 24 hours of light until three days of age, followed by 23 hours of light and one hour of darkness daily. The parameters investigated in this experiment included growth performance, feed consumption, conversion ratio and carcass performance. The bird weights were measured at the beginning of the experiment and on days 21 and 42. Feed consumption on days 21 and 42 was calculated based on the difference between the amount of feed provided and the remaining feed. The weight of dead birds was used to correct the amount of feed consumption. On day 42, one male quail and one female quail were randomly selected from each replicate and killed after 6 hours of starvation. Additionally, after sampling the liver and magnum tissues, their histomorphological characteristics (nuclear diameter of hepatocytes, diameter of sinusoids in the liver tissue; epithelial height, inner muscle thickness, outer muscle thickness, gland diameter, and gland depth in the magnum tissue) were investigated.

During the breeding period, the quails that received the diet containing 0.95% and 1.05% digestible valine had higher body weight gain (BWG) and feed conversion ratio (FCR), respectively. Feed intake (FI) and mortality were not affected by the treatments. Dietary treatments did not have any significant effect on the carcass characteristics (both male and female). However, the carcass yield was higher in male quails and the relative weight of breast and intestines was higher in female quails. In the treatments containing 1.05% and 1.15% of valine, the diameter of Liver cell nucleus and the diameter of liver hepatocytes were the highest, which indicates liver damage. The volume of sinusoids in female birds increased with increasing valine levels in the diet; So that in birds that received diets containing levels higher than 0.95% valine was more than birds fed with rations containing 0.75% valine. Based on the results of this study, different levels of valine in diets containing 17% crude protein had a significant effect on the histology of the magnum tissue (epithelial height, inner muscle thickness, outer muscle thickness, gland diameter), although only the depth of the glands showed a tendency for significance with 0.85% valine.

Based on the results, increasing the level of digestible valine in low protein diets up to 0.95% improves growth performance and feed conversion ratio in growing quails. However, it seems that the use of high levels of digestible valine in low protein diets (more than 0.85%) may lead to tissue damage in the liver and have a negative effect on growth performance. Further studies are recommended in this field.

Effect of different sources of probiotic and prebiotic on growth performance, carcass characteristics, intestinal microflora, and blood metabolites using 720 Ross 308 commercial male broiler chickens in a 3×3 factorial experiment with three levels of probiotic (without probiotic, probiotic type I and type 2) and three levels of prebiotic (without prebiotic, prebiotic type 1 and type II), in a completely randomized design with nine experimental groups (four replications and 20 birds were studied in each replication. Birds that were fed with diets containing type 2 probiotics had a lower conversion factor (P<0.05). Diets containing prebiotic type 1 as well as diets containing probiotic type II and diets containing probiotic type II and two prebiotics under test reduced serum cholesterol and LDL concentrations (P < 0.05). The effect of the experimental treatments on carcass fat was not significant, but the birds fed diets containing prebiotic type 1 had less abdominal fat (P<0.05). At 21 days old, the population of E. coli in the ileum and ceca of birds that received probiotics, prebiotics, and their combinations decreased (P < 0.05). At 38 days of age, feeding the birds with probiotics and prebiotics and a combination of them reduced the population of E. coli in the ceca and increased lactobacillus in the ileum (P < 0.05). The results of this experiment showed that probiotics or prebiotics assayed in this study have positive effects on the increase of beneficial intestinal bacteria (Acid lactic bacteria), blood biochemical traits, and FCR in broiler chickens.

The quality and quantity of dietary protein are primary factor influencing growth and feed costs. Seeds of faba bean (Vicia faba L), similarly as soybean meal, belong to high-protein feeds. The use of faba beans in poultry feed is limited despite having a suitable chemical composition, the main reason of which is the presence of anti-nutritional factors in this seed. Golestan Agricultural and Natural Resources Research and Education Center has produced a zero-tannin faba bean seeds variety (Mahta cultivar) that does not have the nutritional limiting factors of normal beans. The aim of this study was to investigate the effect of different levels of zero-tannin faba bean seeds (Mahta cultivar) on growth performance, some immune and biochemical parameters of blood, morphology and microbial population of small intestine and meat quality of broiler chickens.

320 of one-day-old Ross 308 broilers with 4 treatments were used in a completely randomized design with 4 replications and 20 equal mixed birds of each sex in each replication for 42 days. Experimental treatments included 1- control diet (without faba beans and based on corn-soybean meal) 2- diets containing 10% zero-tannin faba bean 3- diets containing 20% zero-tannin faba bean and 4- diets containing 30% zero-tannin faba bean. Then, the growth performance of chickens, blood biochemical (triglyceride, cholesterol, LDL, VLDL and HDL concentrations) and immune (heterophil and lymphocyte percentage) indicators, intestinal jejunum morphological (villi length, villi width, crypt depth and thichness of muscle layer) and ileum contents microbial population (lactobacillus and escherichia coli) parameters and meat quality (pH, malondialdehyde, peroxide number and free fatty acids) of broiler chickens were measured and recorded. Finally, the analysis of data was performed using GLM method by SAS software. The means were compared using Tukey's multiple range tests.

The results showed growth performance (feed intake, weight gain and feed conversion ratio) of the whole period (1 to 42 days) of birds fed with different levels of diets containing zero-tannin faba bean (0, 10, 20 and 30%) was not significant. There was also no difference between the growth performance of birds fed diets containing zero-tannin faba bean compared to birds receiving the control diet (without beans). A decreasing linear change in the weight gain of the whole period was observed with the increase in the percentage of zero-tannin faba bean (P<0.05). So, the birds that were fed with the control diet (without beans) and 10% zero-tannin faba bean had a better weight gain compared to other treatments, equal to 1738 and 1748 grams respectively, followed by the birds receiving the diet containing 20% zero-tannin faba bean had weight equal to 1623 grams and finally, the birds fed with a diet containing 30% zero-tannin faba bean had weight equal to 1574 grams (P<0.05). Some blood biochemical and immune parameters of broilers were not affected by different levels of zero-tannin faba bean in the diet. However, the amount of changes in HDL, the ratio of HDL to cholesterol, serum LDL and the percentage of heterophil, lymphocyte and the ratio of heterophil to lymphocyte in the blood of broiler chickens fed with a diet containing 20% of zero-tannin faba bean is worthy of consideration and requires further investigation and study (P>0.10). Also, morphological parameters of intestinal jejunum were not affected by different levels of zero-tannin faba bean in the diet. However, citizenship analysis showed linear changes in villi length, villi width and crypt depth of broiler intestines. The tendency to increase villi length was observed in birds fed diets containing 10% zero-tannin faba bean compared to other diets (P= 0.08). Villi width (P<0.05) and crypt depth (P=0.05) were lower in birds fed diets containing zero-tannin faba bean compared to the control treatment (without faba beans). Microbial population of escherichia coli and lactobacillus ileum contents were not affected by different levels of zero-tannin faba bean in the diet. The use of different levels of zero-tannin faba bean improved meat quality by decreasing pH, malondialdehyde concentration, peroxide and free fatty acids in broiler thighs (P<0.05).

Finally, according to the present results, it seems that among the different levels of zero-tannin faba bean (10, 20 and 30%) in the diet of broiler chickens, the level of 10% zero-tannin faba bean in terms of broiler performance should be more appropriate and competitive with the control diet (without faba beans and based on corn-soybean meal).

With the increasing development of broiler industry, increasing feeding costs and concerns, environmental pollution caused by nitrogen and phosphorus disposal, finding ways to increase the bioavailability of nutrients, including phosphorus, is of great interest. The purpose of this experiment was to investigate the effect of the combination of phytase and synbiotic in phosphorus deficient diets on the performance of broiler chickens.

360 one-day-old broiler chickens of Ross 308 strain were used in a completely randomized design with 5 treatments, 4 replications and 18 birds per replication. The birds were fed with the same rations in the first seven days and the experimental diets were given to them from the age of 8 days. Experimental treatments include 1- Control group (diet containing recommended levels of phosphorous), 2- Diet with phosphorus level less than recommended (75% recommended; low phosphorus diet), 3- Low phosphorus diet + phytase, 4- Low phosphorus diet + Synbiotic, 5- Low phosphorus diet + Synbiotic + phytase. Body weight and feed intake were measured in each period and daily weight gain and feed conversion ratio were calculated. At the end of the period, low density serum  cholesterol concentrations, high density poprupe (HDL) and low density poprupe L (LDL) and alanine aminotransferase (ALT) enzymes were measured.

During growth period (24-7 days), the weight gain of birds that received phytase, synbiotic and synbiotic diets with phytase was higher than birds fed control or phosphorus deficient diets and these birds had higher live weight (P<0.05). There was no difference in carcass yield and relative weight of liver and ventricular fat between treatments. Experimental treatments had no effect on serum concentrations of cholesterol, HDL and LDL and alanine aminotransferase (ALT) in broilers. The level of triglyceride in the blood of birds fed phosphorus-deficient diets was lower than that of birds fed control diets containing synbiotics or synbiotics + phytase (p<0.05).

The use of synbiotec + phytase in phosphorus-deficient diets, while reducing the need for phosphorus mineral source, improves the growth performance of broilers and also reduces phosphorus excretion into the environment.

By increasing the poultry and broiler production industry, concerns for  having a food free of pathogens, and as a result, producing a quality and healthy product are increasing. Therefore, correct and efficient disinfection of poultry diets with maintaining the quality of them is very important. The aim of this study was to investigate the effect of gasification of complete poultry feed by ozone on microbial papulation and the quality of broilers diets.

From 432 commercial male Ross strains in a 2 × 2 factorial experiment with three levels of ozone gas (zero, 20 and 30 ppm) and two levels of low fat (1.5 and 2% vegetable oil for growth and finishing periods respectively) and high fat (3 and 4% of vegetable oil for growth and finishing periods, respectively) were used in a completely randomized design with 6 treatments and 4 replications. Diets were ozonated for 120 minutes at concentrations of 20 and 30 ppm. Aflatoxin B1 levels, microbial papulation and the presence of fungi in the feed as well as oxidation of feed lipids in broiler chickens were assayed  after ozonation.

Aflatoxin B1 was not found in grower and finishe diets. The lipid oxidation in ozonated diets with 30 ppm was significantly higher than non-ozonated diets (P<0.05).

According to the results of this experiment, the use of ozone gas to disinfect the broiler chickens diets, despite the destruction and inactivation of microbes and fungi, increases the oxidation of dietary fats.

 The most important effect of using emulsifiers and l-carnitine in the diet is to help the process of digestion and absorption of fats. Improving the efficiency of metabolizable energy consumption and crude protein when emulsifier and l-carnitine supplements used in the diet indicates the positive effect of emulsifiers on the digestion and absorption of fats and other nutrients. Considering the different metabolic activities l-carnitine and emulsifier (lipidol) in broiler chickens, it seems that the use of these compounds together in low-energy diets can significantly improve the performance of broiler chickens. Therefore, the present research investigated the role of lipidol and l-carnitine supplements in reducing the negative effects of low-energy diets on growth performance, carcass characteristics, nutrient digestibility, blood biochemical parameters and meat oxidative stability of broiler chickens.

The experiment was carried out in a completely randomized design with five treatments in four replicates and 12 chickens in each replicate. Broiler chickens were fed with diets including: 1. control diet 2. Low energy diet (150 kcal/kg less than the control diet) 3. Low energy diet + 100 ppm l-carnitine 4. Low energy diet + 1 g / kg lipidol 5. Low energy diet + 100 ppm l-carnitine + 1 g / kg lipidol for 42 days. Then, the growth performance of chickens, carcass characteristics, blood biochemical indicators (total antioxidant capacity, triglyceride, cholesterol, LDL and HDL concentrations), nutrient digestibility (dry matter, protein, fat and organic matter) in starter and grower periods and meat oxidative stability of broiler chickens were measured and recorded. Finally, the analysis of data was performed using GLM method by SAS software. The means were compared using Tukey's multiple range tests.

The results showed that there was no difference in feed intake between the birds receiving the control diet and the other diets. Weight gain and feed conversion ratio of birds were significantly improved by control diet than other treatments (P<0.05). However, birds receiving low-energy diets containing lipidol + l-carnitine had the same feed conversion ratio (1.79) as birds receiving the control diet (1.75). Birds fed with low-energy diets containing lipidol and lipidol + l-carnitine had better weight gain and feed conversion ratio than birds fed with low-energy diets containing l-carnitine and without additives (P<0.05). Compared to the control treatment, the birds that were fed with low-energy diets containing lipidol and l-carnitine separately and together had a lower abdominal fat percentage (0.4%) (P<0.05). Also, birds fed with the control diet showed a tendency to increase the heart percentage compared to other experimental treatments (P=0.06). Birds fed with low energy diets containing lipidol and lipidol + l-carnitine had higher dry matter (3.6%), protein (7.8%) and fat (6.6%) digestibility in the starter period and higher digestibility of dry matter (6.9%) in the grower period compared to other treatments (P<0.05). In general, in the starter period, the birds fed with control diet showed lower digestibility of protein (P=0.06) and fat (P<0.05), and in the growth period, the digestibility of dry matter was lower than the birds fed with other diets. Birds that were fed with low energy diets containing lipidol and l-carnitine separately or together had higher total antioxidant capacity compared to birds fed with control diet and low energy diet without additives (P<0.05). Also, birds that were fed with low-energy diets containing l-carnitine and lipidol + l-carnitine had lower blood triglyceride (P=0.05) cholesterol and LDL concentrations compared to birds fed with control diet and low-energy diet without additives (P<0.05). Birds fed with low energy diet containing lipidol + l-carnitine increased blood HDL level compared to birds receiving low energy diet without additives (P<0.05). Birds that were fed with low-energy diets containing lipidol and l-carnitine separately and together had lower concentrations of malondialdehyde in thigh and breast meats on days 3, 6 and 9 after slaughter and kept in a refrigerator (4ﹾC) compared to birds fed with low energy diets without additives and control diet (P<0.01). 

Finally, the simultaneous utilization of 100 ppm l-carnitine and 1 g / kg lipidol in low-energy diet showed similar growth performance when compared with control diet and led to improved carcass quality, fat, protein and dry matter digestibility, blood lipid parameters and meat shelf life of broiler chickens.

 Rooster’s reproductive performance is an indispensable component of breeder production because it plays a vital role in the maximum production of fertilized eggs. Existence feed supplement in the poultry industry, intermediary metabolites have been including in the diet to improve fertility and reproductive outcomes. Carnitine (β-hydroxy-γ-trimethylaminobutyrate), vitamin-like-amino acid, is a quaternary ammonium compound, that has multifunctional roles in reproduction. High concentrations of L-carnitine (LC) are present in epididymal lumen, where it participates in sperm energy balance and the maturation of spermatozoa. In light of previously reported breeder birds supplemented with dietary LC have shown improvements in semen traits and fertility parameters. The present study is an attempt to investigate the effects of several levels of dietary LC supplementation on semen quality parameters and gonadosomatic and hepatosomatic indexes at maturity and production peak.

For the present experiment, thirty-six Ross (12-week-old) breeder broilers were used for 22 weeks in a completely randomized design with three treatments (0, 250 and 500 mg L-carnitine in kg of diet) and twelve replications. All roosters were fed standard isocaloric (2754 kcal/kg) and isonitrogenous diet (12 % protein). The birds for 22 weeks in a completely randomized design with three treatments (0, 250 and 500 mg / kg of LC in the diet) and six replications were used. During the adaptation period (21-24 weeks of age), the roosters were trained by abdominal massage for semen collection. After the experimental period was commenced (24 weeks of age), semen samples were collected and evaluated for seminal attributes every two weeks (from week 24 to week 34). The following parameters were determined immediately after the semen collection; to measure the semen samples were collected weekly to evaluate semen volume, total motility, membrane functionality, mitochondria activity parameters. Also, to determine gonadosomatic and hepatosomatic indexes at 24 and 34 weeks of age, six birds in each treatment weighing then were slaughtered and immediately the testes and liver were removed and weighed.

The highest sperm motility (96.60%) was observed in birds fed 250 mg LC (P <0.04). By increasing the level of LC in the diet, sperm membrane functionality improved linearly (6.8% increase compared to control) (P <0.04). A linear trend (P = 0.06) was observed in mitochondrial activity with increasing levels of LC in the diet (69.31, 72.00 and 76.25). LC plays an essential role in energy metabolism by carrying over fatty acids in the mitochondria matrix for β-oxidation producing energy. Therefore, it provides a better supply of energy for spermatogenesis and normal physiology of sperm, are presumably improved by an optimum level of LC, as a result, sperm concentration and live. These data provide evidence that LC can be effectively used in diets up to 500 mg/kg of diet or 30 mg/kg of body weight /day for semen improvements of rooster’s breeder. At 24 weeks of age, the changes in gonadosomatic index (0.55, 0.68 and 0.64) were affected by different levels of LC (P <0.01). During testis development in the chicken (from 2 to 15 weeks of age), there is no significant increase in testicular weight, however, the early stage is the most important period for testicular development. The mature testis has seminiferous tubules with a multilayered epithelium representing the different stages of spermatogenesis. Sexual maturity is associated with the highest testes weight and consequently with the highest plasma concentration of reproductive hormones. Gonads of the mature male broiler breeder are organized into separate, comfortably discernible cellular correlations and functional compartments. It has been accepted that steroid hormones biosynthesis and generation of spermatozoa are two major actions that the testicles fundamentally carry out. The improvements in gonadosomatic Index of roosters observed in this study in response to dietary LC may be attributed, at least partly, due to improved utilization of dietary nitrogen, achieved through more efficient fat oxidation by LC. Testicles contain the seminiferous tubules and the interstitial space. Seminiferous tubules are the functional elements of the testis and sertoli cells are the principal structural basis of the seminiferous epithelium, inhabiting on the substratum membrane.

The addition of 250 and 500 mg of L-carnitine to the diet due to the increase in gonad index led to an improvement in sperm quality parameters at the beginning of the production period (puberty).

The aim of this study was to investigate the effect of emulsifier in diet with with energy reduction on performance, carcass characteristics and some of blood traits of broilers. A total of 540 one-day-old chicks of Ross 308 strain in a 3×3 factorial arrangement with three levels of emulsifier (0, 250 and 500 mg / kg) and three levels of dietary energy (requirement, and 45 and 90 kcal/Kg, 60 and 105 kcal/kg and 75 and 120 kcal/kg less than requirement for the starter, grower and finisher diets, respectively) in a completely randomized design with 9 treatments, 4 replications and 15 birds per replication were used. In total rearing period, feed intake increased by decreasing the dietary energy (P<0.05). Birds fed diets supplemented by emulsifier had higher weight gain and lower feed conversion ratio (P<0.05). The relative weights of the liver, ceca, and abdominal fat were not affected by different levels of dietary energy. The emulsifier × diet interaction had no significant effect on cholesterol, High-density lipoprotein (HDL), Low-density lipoprotein (LDL), cholesterol: HDL, Alanine aminotransferase (ALT) and alkaline Phosphatase. Adding emulsifier to normal diets or diets with more energy deficiency increased blood triglyceride concentration (P<0.05). Supplementing diets with mild energy deficiency by emulsifier increased serum Aspartate aminotransferase (AST) (P<0.05). According to the results, the use of 250 gr/t emulsifier in low energy diets improved the performance of broiler chickens.

Omega-3 fatty acids can be conducive toreducing the harmful effects of physiological stress through reducing the stimulatory activity of glutamatergic neurons.

The aim of this study was to investigate the effects of omega-3 fatty acids on performance, blood parameters, and the profile of fatty acids in the egg yolks of laying hen under stress.

This study was performed using 96 LSL-Lite laying hens in a 2 × 3 factorial experiment with 2 factors, namely stress (no dexamethasone and 1.5 mg/kg of diet dexamethasone) and omega-3 fatty acids (the levels of 0, 0.24 and 0.48 % of diet), in a completely randomized design for 70 days from 35 to 44 weeks of age.

Physiological stress reduced the feed intake, the percentage of egg production, and egg mass in laying hens (P<0.05). Omega-3 fatty acid supplements had no effects on these traits. The groups receiving 0.48 % of omega-3 fatty acids had the lowest heterophil:lymphocytes (P<0.05), and there was no difference between stressed and non-stressed groups. The ratio of omega-6 to omega-3 fatty acids was higher in birds previously affected by stress (P<0.05). Feeding with omega-3 fatty acids in birds increased omega-3 fatty acids in egg yolk and reduced the ratio of omega-6 fatty acids to omega-3 in laying hens (P<0.05).

Based on the results of this experiment, physiological stress had a negative effect on performance traits, and the use of omega-3 fatty acids in laying hens under stress had no effect on performance traits. Physiological stress altered the profile of fatty acids and increased the proportion of omega-6 to omega-3 fatty acids in egg yolk. The use of omega-3 fatty acids reduced the negative effects of stress and improved the profile of fatty acids in egg yolk.

The effects of different sources of copper supplementation on growth performance, some blood biochemical and immune parameters,microbial population of small intestine and meat quality were investigated with using of 240 male broiler chicks in a completely randomizeddesign with 5 treatments and 4 replicates from 1 to 42 days. Treatments consisted of control treatment (basal diet without copper supplement)and four diets containing 16 mg/kg of copper-glycine, copper-sulfate, copper-nanochelate and copper nano-glycinec. The results showed thatthe use of different sources of copper had no effect on growth performance, some blood biochemical parameters and percentage ofheterophil, lymphocyte, white blood cell, antibody titer against Newcastle disease, cholesterol, triglycerides and water holding capacity andpH of meat of broilers. Gastrointestinal relative weight in birds fed with diet containing copper-glycine was lower than the birds receivingcopper-nanochelate (P<0.05). The total microbial population of ileum in birds fed diets without copper and copper-sulfate was higher thanbirds receiving diet containing copper-glycine (P<0.01). Meat malondialdehyde concentration of birds fed with diets containing copperglycineand copper nano-glycine after 6 day of storage at refrigerator was lower than other birds (P<0.01). According to the results, the useof 16 mg/kg of copper from organic, mineral and nano sources in the diet has no effect on growth performance, immune system and ilealmicrobiota in broilers, but the use of copper-glycine and copper nano-glycine supplements in the diet reduces the oxidation of meat.

The effect of L-carnitine in omega-3 rich diets on the production performance and immune system of One hundred tewnty 34-week-old Lohmann LSL-Lite laying hens were used in 2 × 3 factorial arrangement with two types of diets (without omega-3, Enriched with Salomega at the rate of 3%) and three levels of L-carnitine (0, 100 and 200 mg / kg) were evaluated in a completely randomized design with 6 treatments and 5 replications and 4 birds per replication for 70 days. The Egg Production Percentage percentage of birds fed with diets enriched of salomega increased compared to diets without omega-3 (P <0.05). Egg shape index in birds fed with diets containing 200 mg / kg L-carnitine increased compared to diets without L-carnitine (P <0.05). Egg mass of birds receiving omega-3 without diets and L-carnitine or 100 mg / kg L-carnitine and/or diets enriched of salomega containing 200 mg / kg L-carnitine increased compared to other groups (P <0.05). The height of yolks and whites and haugh unit eggs of birds fed with diets containing 100 mg / kg L-carnitine increased compared to diets without L-carnitine and 200 mg / kg L-carnitine (P <0.05). HET:LYM ratio in the blood of birds fed with diet enriched of salomega decreased compared to diet without omega-3 (P <0.05). It seems that the use of 200 mg / kg L-carnitine with 3% omega-3 fatty acids with salomega source can improve productive performance and quality traits of eggs. Further studies in this area are recommended.

The effect of garden thyme essential oil (TEO) and rapeseed oil (RO) on performance, immune traits and intestinal morphology using 432 one-dayoldRoss 308 male broiler as a (3x3) factorial experiment in a completely randomized design including different levels of TEO (0, 300 and 500 ppm)and RO (1, 3 and 5 percentage) were evaluated with 9 treatments and 4 replicates. Throughout the rearing period, broiler chickens receiving 3%gained more weight than 1% of RO and chickens receiving 300 ppm gained more weight than those without TEO (P˂0.05). The use of 3% RO + 300ppm TEO increased the thigh percentage compared to 1% RO. At 1 and 5 percentage levels of RO, with increasing levels of TEO in the diet, bloodcholesterol and LDL concentrations decreased and blood HDL increased (P<0.01). Levels of 3% and 5% of RO + 300 and 500 ppm of TEO in broilerchicken diets increased lymphocyte percentage and antibody titer against Newcastle disease and decreased heterophil percentage and heterophil tolymphocyte ratio of blood (P<0.05). Broiler chickens receiving diet containing TEO had the highest ratio of villi height to crypt depth (P<0.01). Basedon the results, the level of 3% rapeseed oil + 300 ppm thyme essential oil in the diet of broiler chickens can be used to improve performance,immunity and biochemical traits of blood.

This experiment was conducted to investigate the effect of graded creatine monohydrate levels on diets at different levels of protein on carcass characteristics and hematological parameters. A total of 320 Ross 308 one-day-old broilers were in the form of 2*4 factorials, with four levels of creatine (zero, 0.1, 0.3, 0.5%), and two levels of protein (requirements of Ross 308 and 10% higher), with four replicates, were used. Blood sampling was performed at 35 days of age. To investigate the carcass characteristics, at the end of the experiment two birds at each replicate were randomly selected, weighed and slaughtered. 10% higher protein requirement increased daily weight gain, live weight, carcass yield, relative liver, and breast weight, and decreased feed conversion ratio and abdominal fat (P<0.05). Adding 0.3% and 0.5% creatine monohydrate to the diet increased live weight, carcass yield and relative weight of breast and thigh compared to other groups (P<0.05). Protein and creatine levels had no effect on immune cells and Newcastle titer; however, the data indicated a numerical increase in lymphocyte, monocyte and Newcastle titer and a decrease in heterophil. Creatinine concentration in the blood of birds fed with 0.3 and 0.5% creatine monohydrate was higher than broilers fed with 0.1% creatine monohydrate and control group (P<0.05). The results showed that moreover the beneficial effects of creatine at high levels and 10% higher protein requirements on growth performance and carcass traits, blood creatinine concentrations should be increased which could potentially improve immune system function.

Plasma lipoprotein profile is one of the effective mechanisms in testicular tissue development and spermatogenesis process in roosters.

The present study was conducted to investigate the effect of dietary supplementation of l-carnitine during pre-pubertal period on testicular histology, spermatogenesis indexes and plasma lipoproteins of immature cockerels

A total of twelve Ross broiler breeder males (12 weeks) for 22 weeks in a completely randomized design with two treatments (0, and 250 mg/kg of L-carnitine in the diet) and six replications were used. Feeding program, and photoperiod regimen was performed based on ROSS 308 management handbook. To achieve the objectives of the study, at the age of 34 weeks, four birds were randomly selected from each treatment and after collecting blood samples from the veins under the wings, the birds were slaughtered. Finally, plasma cholesterol, LDL and HDL concentrations using a commercial kit and testicular parameters (number of seminiferous tubules, number of Sertoli cells, height of epithelium seminiferous tubules, seminiferous tubules diameter, spermatogenesis index, and tubular differentiation index) after preparation of 5-μm paraffin sections, were analyzed by SAS software.

The results showed that the number of seminiferous tubules, and the number of Sertoli cells were significantly affected by l-carnitine (p < /em><0.05). L-carnitine supplementation in the diet of immature cockerels before sexual maturity significantly increased the spermatogenesis index (p < /em><0.003) and tubular differentiation index (p < /em><0.02). HDL levels were significantly affected by l-carnitine supplementation (p < /em><0.007). There was a significant tendency in LDL concentration (p < /em>=0.09) and LDL/HDL ratio (p < /em>=0.059) between treatments, but no significant differences were observed in cholesterol concentration between treatments.

According to the results of this study, feeding immature cockerels before sexual maturity with 250 mg l-carnitine improves testicular tissue development and spermatogenesis process.

All breeds of Irannians sheep except Zel has a fat tail, and despite their lower carcass fat percentage, male lambs have higher fat-tail weight. Using within breed genetic variation requires accurate and precise measuring of fat tail weight on candidates of selection. The aime of this study was comparision of artificial neural network (ANN) modeling and linear modeling methods to prediction of fat tail weight, using body weight and different tail dimensions. 32 lambs of Chal and Zandi breeds,crosses of Zandi×Chal,Zel×Zandi and Zel×Chal hybrids were used for modeling to an estimation of fat-tail weight. Inputs of the model was birth type, sex, breed, upper width , mid width and lower width of fat tail,fat tail height and body weight, output of the model was fat tail weight. body weight, genotype, and fat tail mid-width had the largest positive correlations with fat-tail weight,0.83,-0.82 and0.80,respectively. The adequacy parameters of the best artificial neural network model had a coefficient determination of 0.99 and a mean squared error(RMSE)of 70.3g. The values of these estimated parameters by the multiple linear model were 0.891 and 263.86, respectively. The results of the extension of the original study showed the complexity of the interactions between the model inputs. Present research approved to accurate and unbiased estimation of tail weight of different breeds and crosses using artificial neural network. Furthermore, present study showed that ANN model can be used for accurate and presise estimation of fat tail weight using measured traits on sheep,than linear model.

In poultry farms, the stresses are inevitable, therefore, it is very necessary to achieve an efficient and practical way to control and reduce its negatives effects. Thus, this study was conducted to evaluate the effects of different sources of chromium on thyroid hormones and some blood parameters of broiler chicks under physiological stress conditions. A total of 216 one day old Ross broiler chicks (male) were used in a 3 × 2 factorial arrangement with two stress conditions (no stress, stress) and three levels of additive (no Additive, 2000ppb chromium-methionine, and 2000ppb chrome-methionine mill) in a completely randomized design with 6 treatments, 3 replicates and 12 bird per each. Dexamethasone was added to the diet (1.5 mg/kg diet) during 24-18 days of age to induce physiological stress. The birds were fed with chromium diets from 18 d until the end of the experiment. Blood samples were taken at 24 and 46 days of age via brachial vein and then analyzed for blood glucose, lipids, cortisol, thyroxine (T4) and thyroid iodothyronine (T3). Physiological stress reduced the concentration of thyroid hormones, glucose, serum lipids and cortisol hormones. In stressed birds, the use of chrome methionine diet significantly reduced cholesterol of serum. Chromium supplementing diet increased thyroxine (T4) concentration. Dietary chromium methionine significantly decreased cortisol concentrations of serum. Based on the results, adding chromium ppb 2000 from various sources reduces the effects of physiological stress on thyroid hormones and cholesterol concentrations in the serum of birds under physiological stress.

This study was conducted to evaluate the effects of particle size of chromium-methionine (Cr-Met) on growth performance, carcass traits and meat quality of broiler chicks under physiological stress conditions. A total of 288 broiler chicks (male) were used in a 2 × 3 factorial arrangment with two stress status (no stress, stress) and three levels of Cr-Met (no Additive, 2000 ppb of Cr-Met, and 2000 ppb of Cr-Met milled) in a completely randomized design with six treatments, four replicates and 12 birds per each pen. Dexamethasone was added to diets (1.5 mg/kg diet) for a week (18-24 d) to induce physiological stress. Feed intake and body weight were measured weekly and feed conversion ratio was calculated. The malondialdehyde content and the water holding capacity of meat were measured at 24 and 46 d of age. Also, breast meat pH was measured at 46 d. Physiological stress decreased feed intake, weight gain, carcass yeild, relative weight of spleen, bursa, heart and liver, but increased FCR and water holding capacity of meat bereast (P<0.05). In stressed birds, both forms of dietary Cr- Met improved FCR and increased the meat pH (P<0.05). There were no differences between the effects of particle size of Cr-Met on the studied parameters. According to the results of this experiment, dietary supplementation of 2000 ppb Cr-Met in different sizes reduced the negative effects of physiological stress and improved the FCR and carcass yield of birds under physiological stress.

The effect of omega-3 fatty acids on performance and physical characteristics of eggs in laying hens under physiological stress was evaluated using 96 LSL-Lite layers in a 2 × 3 factorial experiment with two levels of stress (stress and non-stress) and three levels of omega-3 fatty acids (0, 0.24 and 0.48% of diet) in a completely randomized design for 70 days. From age of 35 to 40 weeks, birds were fed with basal diet and various levels of omega-3 fatty acids, at 41 weeks of age. Physiological stress was induced by adding 1.5 mg dexamethasone/kg of diet for one week. Dexamethasone was then removed from the diet and the birds were fed with pre-stressed diets for three weeks (post-stress period). Percentage of production, feed intake, egg mass, as well as physical traits of eggs in stress and post-stress periods were evaluated. During the stress period, the percentage of egg production, weight and egg mass, shell thickness decreased under stress while feed conversion ratio increased (P<0.05). Feed intake of stressed birds fed diets containing different levels of omega-3 fatty acids was lower than other groups (P<0.05). The lowest yolk index was observed in the stressed birds fed diets containing levels of 0.24 and 0.48 % omega-3 fatty acids. In the post-stress period, the egg production, egg mass, feed intake in birds that experienced stress was lower than non-stressed birds and had higher feed conversion ratio (P<0.05). During this period, the shell thickness of the stressed birds receiving level of 0.48% of the omega-3 fatty acids was lower than other groups (P<0.05). In general, the use of omega-3 fatty acids in stressed laying hens with the intensification of reduced feed intake can increase adverse effects of stress on the performance and egg quality.

The effect of feeding L-carnitine during pre-puberty on the quality parameters of fresh and frozen-thawed semen by using 12 Ross broiler breeder males (12 weeks) for 18 weeks, in a completely randomized design with three treatments (0, 250 and 500 mg / kg of L-carnitine in the diet) and four replications was performed. From the age of 26 to 29 weeks, semen collection was performed using abdominal massage. The sperms taken each time after dilution (with Beltsville diluent) were divided into two parts, one section was frozen and the other part was immediately examined. Motility (total and forward), viability, morphology, membrane functionality and lipid peroxidation parameters were evaluated. In fresh sperm, the correlation between L-carnitine and abnormalities was negative linear, and with viability was positive linear (P<0.05). Quadratic analysis was significant in forward Motility and MDA concentration (P<0.05). Birds that use diets containing L-carnitine, In terms of forward motility, viability, morphology and MDA concentrations in fresh sperm, And these traits, with the total motility and integrity of the plasma membrane of frozen sperm, were higher in comparison to the control group (P<0.05). Also, in the sperm after frozen-thawed, the correlation between L-carnitine and Motility (total and forward), viability and membrane integrity were positive linear (P<0.05), and the correlation between L-carnitine and MDA concentration was negative linear (P<0.05). The correlation between L-carnitine and Motility (total and forward), membrane integrity and MDA concentration were quadratic (P<0.05). According to the results, Dietary L-carnitine supplementation in pre-puberty improves the qualitative traits of sperm before and after freezing in the breeder broilers.

The effects of different sources of selenium supplementation and rosemary essential oil on growth performance, microflora population and intestinal morphology in broiler chicken with using of 480 male broiler chicks in a factorial arrangement (2x5) with 10 treatments and 4 replicates were investigated. Two experimental factors consisted of different sources of selenium (level of 0.3 mg/kg of diet from selenomethionine, nanoselenomethionine, selenitsodium, nano selenium bonza and without selenium) and rosemary essential oil (0 and 300 mg/kg of diet). Results showed that broilers received diet of without Se and rosemary essential oil had lower weight gain and feed intake.Broilers received diet of nano selenium bonza with rosemary essential oil had lower feed conversion ratio as compared to the other broilers (P<0.05). Broilers fed on diets of nanoselenomethionine with rosemary essential oil and nano selenium bonza with rosemary essential oil were increased villus height in jejunum (P<0.05). The crypt depth of intestinal in birds which received nanoselenium was more than the birds that consumed other sources of selenium in the diet (P<0.05). Crypt diameter nano selenium bonza with rosemary essential oil treatment was higher as compared to other treatments (P<0.01). Selenomethionine and nanoselenomethionine alone and in combination with rosemary essential oil treatments had high lactobacillus population and lactobacillus population to total microbial population ratio of ileum as compared to without Se and rosemary essential oil treatment (P<0.05). Based on the results, inclusion nanoselenium (0.3 mg/kg) supplement with rosemary essential oil (300 mg/kg) into the diet of broiler chicken can improve performance, gut morphology and microflora.

Today, the use of antibiotics is limited as a growth promoter. Silver has been known for its antimicrobial properties over the past, and it is said to increase its antimicrobial properties by decreasing the particle size to nano scale. The aim of this study was to evaluate the effect of silver nanoparticles on immune system and blood lipids and microbial population of broiler chickens and compare it with flavomycin. A total 312 day-old broilers (Arbor-Acre Plus) were used in a completely randomized design with 6 treatments diets and 4 replicates per each replicate. The nano-silver solution (2000 ppm) was used in 400 and 800 cc per ton diet or 1000lit water to prepare treatments. Two treatments with and without antibiotic (flavomycin 500g/t) were considered as control groups. Number of monocytes increased significantly in birds received diets or drinking water containing 800 ml silver nanoparticles (p< 0.05). Different levels of silver nanoparticles in diet or drinking water had not significant effects on concentration of cholesterol, low density lipoprotein (LDL) and high density lipoprotein (HDL) of serum and coliform bacteria in the ileum. But the number of cholestridia in the ileum of birds received 800 ml silver nanoparticles in diet or drinking water increased significantly (p< 0.05). The results indicate that silver nanoparticles are not suitable for using as feed additives to encourage immune system and control pathogenic bacteria in broilers gut. Further studies are needed.

Although numerous reports support the beneficial effects of supplementing chromium (Cr) on broiler performance under normal and stress conditions, the optimal level has not been determined yet.

This study was conducted to investigate the effects of different levels of supplemental Cr on performance, cortisol, and thyroid hormones of broiler under normal and stress conditions.

A total of four hundred forty-eight broilers were used. Broilers allocated into 2×4 factorial experiment included: stress (normal and stress) and 4 levels of supplemental chromium (0, 1000, 2000, 3000 ppb) since day 18. A completely randomized design with 8 treatments and 4 replicates (14 birds per replicate) was used. Dexamethasone used as a stressor for one week (stress period, STP) then experiment continued to day 46 (recovery period, RCP).

Feeding 1000 and 2000 ppb Cr improved feed conversion ratio (FCR) and increased T4 compared to 0 and 3000 ppb Cr in stressed broilers in STP (P<0.05). Feed intake (FI), body weight (BW) and T3 concentration were higher in broilers fed with 1000 ppb Cr in the diet and reared without stress in STP (P< 0.05). Despite the negative effect of stress on performance in RCP, dexamethasone-stressed broilers had better FCR. Feeding stressed birds with 1000 ppb Cr increased blood cortisol whereas it reduced cortisol in the normal-reared birds.

The Dietary supplementation of 1000 and 2000 ppb Cr reduced deleterious effects of physiological stress. Moreover, 1000 ppb Cr improved FI and BW of broilers under normal condition at first week. Feeding high level of chromium under normal and stress conditions did not improve the performance.

Antioxidant compounds and unsaturated fatty acids play an important role in improving the immune response and intestinal microflora in broiler chickens. The aim of this study was to investigate the effects of different sources of antioxidant and soybean and rapeseed oils on humoral immune responses, intestinal microflora and some of the blood parameters of broiler chicken. A total of 480 male broiler chicks (Ross 308) were randomly allocated in a factorial arrangement (2×5) based on a completely randomized design with 10 treatments and 4 replicates during 42 days of age. Experimental factors consisted of different sources of antioxidant (rosemary, thymus and satureja essential oils at level of 300 ppm and vitamin E at concentration 200 mg/kg and without antioxidant) and vegetable oils (soybean and rapeseed oils at concentration of 4 percent of diet). Immune characteristics and intestinal microflora population were evaluated. The use of different soybean and rapeseed oils had no significant effect on antibody titer (P>0.05) but the use of antioxidants improved immune responses against Newcastle disease (P<0.01). Also, the use of rosemary, thymus and satureja essential oils increased serum level of blood high density lipoprotein and reduced blood low density lipoprotein (P<0.001).  Furthermore, the concentrations of cholesterol and triglyceride increased in without  antioxidant treatment (P<0.001).Also, use of antioxidant treatments caused significant decrease of heterophil to lymphocyte ratio (P<0.05), then these result are consistent with the immune response against Newcastle disease. Furthermore, escherichia coli to lactic acid bacteria ratio increased in rosemary and thymus essential oils treatments compared with without antioxidant treatment (P<0.05). The use of dietary soybean and rapeseed oils did not have a significant effect on different traits of broiler chicken, but adding dietary antioxidants improved immune responses and intestinal microflora and in between different antioxidants, the use of essential oils compared with vitamin E  induced significant improvement of traits.