نشریه پژوهش های علوم دامی
سال سی و دوم شماره 1 (بهار 1401)

The ideal performance of poultry is achieved by adequately feeding of birds while reducing dietary costs and nutrients excretion. On the other hand, the amount of dietary nutrients can have a significant effect on feed intake (Kidd et al., 2002). Studies have shown that reduced growth and yield due to decreased dietary protein can be compensated by supplementing the synthetic amino acids (Hussein et al., 2001). Diets based on total and digestible amino acids can improve the performance (Rostagno et al, 1995). Some properties of valine and tryptophan in relation to non-protein function and metabolism distinguish them from other amino acids. Valine is the fourth limited amino acid to the growth of broilers. Tryptophan involved in all proteins structure and is a precursor for serotonin and melatonin, which in addition to improving food intake (Silber and Schmitt, 2010). Valine affects the ghrelin and neuropeptide Y production (Coto et al, 2006) while tryptophan affects the serotonin secretion (Henry, 1985) that both affects the feed intake. The functions of the two amino acids can improve the performance and immune system of birds.

The current experiment was performed to evaluate the effects of different levels of valine and tryptophan amino acids in low-protein diets on carcass characteristics and immune response of broiler chickens. A total of 450 day-old Ross 308 broiler chickens were randomly divided into nine treatment groups. The chickens were arranged in a 3×3 factorial experiment based a completely randomized design including 3 levels of valine and three levels tryptophan. Each treatment considered of five replicates and 10 chickens per experimental unit. The birds were reared on the litter pen for 21 days with ad-libitum access to feed and water. Diets were formulated based on linear programming by using of the UFFDA software. Experimental treatments were adjusted based on Brazilian tables and included: 1- recommended level of valine + recommended level of tryptophan, 2- recommended level of valine + 5% more than recommended tryptophan, 3-recommended valine level + 10% more than recommended tryptophan, 4-10% more than recommended valine level + recommended level of tryptophan, 5-10% more than recommended valine + 5% more than recommended tryptophan, 6- 10% more than recommended tryptophan level + 10% more than recommended tryptophan, 7- 20% more than recommended valine level + recommended level of tryptophan, 8- 20% more than recommended valine + 5% more than recommended tryptophan, 9-20% more than recommended valine level+ 10% more than recommended tryptophan. On day 21 of experiment, two birds per pen were randomly selected and slaughtered for whole carcass analysis after 12 hours of fasting. After slaughter, the organs such as breast, thigh, abdominal fat, gizzard, liver, heart, spleen, thymus and burs fabricius were weighed. In order to determination of white blood cells, blood sampling drawn from the wing vein at 21 days of age and the number of lymphocytes, heterophils, monocytes, basophils and eosinophils were determined. Blood samples were taken at 21 days of age as well to determination of the antibody titer of Newcastle virus. To measure the immune response to sheep erythrocytes, 2 ml of blood was taken from the chicken vein on 14 and 21 days of the experiment and used to determination of total immunoglobulin and IgM and IgG titers. The antibody titers were performed by direct hemagglutination (Isaco et al. 2005). The CBH test was used to evaluate the cellular immunity. The experiment was conducted using completely randomized design with factorial structure. Data were subjected to ANOVA using the GLM procedure (SAS, version 9.1) as a 3×3 factorial. Significant means among the variables were separated by Duncan's multiple range tests at 5% level of significance.

The results of current experiment showed that the addition of valine and tryptophan in low protein diets had no significant effect on carcass yield, thigh, gizzard, heart and abdominal fat (p<0.05). The consumption of 20% and 10% levels of valine significantly increased the breast weight as compared to the recommended level (p<0.05). No interaction effects was observed between the valine and tryptophan amino acids for the weights of carcass parts and internal organs (p>0.05). In a study, consumption of 10 and 20% tryptophan levels had no significant effect on breast and thigh of broilers at 22 days of age (Duarte et al, 2013). Moreover, addition of valine to poultry diets did not have a significant effect on abdominal fat weight (Corzo et al, 2004). Different levels of valine and tryptophan had no affected the liver and spleen weight (p<0.05). Furthermore, addition of 20% valine caused an increase in thymus and bursa weights (p<0.05). The diets containing tryptophan had a significant effect on the number of blood lymphocytes, so that the addition of 10% tryptophan increased the blood lymphocytes (p<0.05). Valine and tryptophan addition did not affected the other blood leukocytes (p<0.05). Addition of 20% valine increased the humoral immunity (HI antibody titer) (p<0.05). Also, addition of 10% tryptophan level increased the immunity of chickens against HI antibody (p<0.05). The results showed that the initial response of total antibody was not affected by experimental treatments (p<0.05) but 10% level of valine significantly increased the IgM (p<0.05). Dietary addition of 20% valine had a significant effect on IgM secondary response SRBC (p<0.05) but had no significant effect on the PHA-P injection response (p<0.05). It has been reported that protein deficiency have caused the unsuitable growth of lymphoid organs (Corzo et al., 2007).

The result of current experiment showed that consumption of high valine and tryptophan levels in low-protein diets improved the carcass characteristics and immune system of broilers.

Fermented Saccharomyces cerevisiae are used as a new additive in animals (Heidarieh et al., 2013). These products contain nucleic acids, chitin, beta-glucan and mannoligosaccharides. Researchers reported that feeding by Saccharomyces cerevisiae improves, improves growth performance in broilers (Baurhoo et al., 2006). Consumption of fermented Saccharomyces cerevisiae in rainbow trout, increased feed uptake and improved feed conversion ratio (Heidarieh et al., 2013). Due to the aforementioned effects of fermented Saccharomyces cerevisiae and insufficient reports on its use in broilers, the aim of this study was to investigate its effect on growth performance and immune responses.

An experiment was conducted as a completely randomized design using 240 day-old chicks (mixed sex) with four treatments, five replicates, and 12 chicks in each replicate from 1 to 42 days of age. Experimental treatments were included: (1) control group (basal diet without any feed additive), (2) basal diet+ 0.1 percent fermented Saccharomyces cerevisiae (3) basal diet + 0.3 percent fermented Saccharomyces cerevisiae and (4) basal diet + 0.5 percent fermented Saccharomyces cerevisiae.Chicks in each replicate were weighed weekly and feed intake was determined at the end of each week. From these data, average daily weight gain, average daily feed intake and feed conversion ratio were calculated. On day 42 of experiment, two birds (one male and one female) from each replicate were selected, weighed, then slaughtered and carcass yield and carcass components including breast, thighs, wings, abdominal fat, thymus and bursa of Fabricius were weighed using a digital scale and their relative weights to body weight were calculated.In order to assess the systemic antibody response, chicks were immunized by intramuscular injection of 0.1 mL of 25 % sheep red blood cell (SRBC) in PBS on days 8 and 22. Blood samples were collected from two birds of each replicate via the wing vein and serum antibody levels produced in response to SRBC were measured on days 21, 28, 35 and 42 (Salehimanesh et al., 2015). Skin response to intradermal injection of Phytohemagglutinin-P (PHA-P) was measured on day 16 during 24 and 48 h after injection (Grasman, 2010). Data were analyzed using the GLM procedure of SAS (SAS Institute, 2001) in a completely randomized design and means were compared using Tukey’s multiple range test at P<0.05.

The results indicated that treatments had no significant effect on daily feed intake (P>0.05) but daily weight gain and feed conversion ratio improved in all groups receiving fermented Saccharomyces cerevisiae (P<0.05). The beneficial effects of Saccharomyces boulardii and Bacillus cereus (Gil et al., 2005) and prebiotic (Fermacto) (Rodrigues et al., 2005) on broiler performance have been identified. It was reported that the use of probiotics (Primalac and Bacillus amyloliquefaciens) did not effect on daily feed intake (Yakhkeshi et al., 2012). In contrast, the use of lactobacillus reduced the daily feed intake of broilers (Murry et al., 2006). The difference can be due to the type and dose of the probiotic. By examining the effects of Saccharomyces cerevisiae and Bacillus subtilis on broiler performance, it was found that the probiotics increase growth performance, feed intake, and feed conversion ratio (Chen et al., 2009). It was reported that the use of 1.5 and 2% Saccharomyces cerevisiae (Sc47) in the diet of broiler chickens increased daily weight gain (Ghasemi et al., 2006). It was reported that addition of probiotic (containing Bacillus subtilis) in broiler chickens, improved the feed conversion ratio from 21 to 42 days of age (Fritts and Waldroup, 2003). In a study performed on broiler chickens fed mannanoligosaccharide (isolated from the cell wall of Saccharomyces cerevisiae), it was found that the feed conversion ratio was significantly reduced compared to chickens fed a mixture of probiotics and organic acids (Derebasi and Demir, 2004). Saccharomyces cerevisiae improves feed intake by stimulating beneficial microbes in the digestive tract (Kocher et al., 2004).The results indicated that treatments did not affected on carcass efficiency, breast, thigh and wing (P<0.05). All amounts of fermented Saccharomyces cerevisiae increased bursa of Fabricius and thymus weight ratio (P<0.05). Consumption of 0.1 and 0.3% fermented Saccharomyces cerevisiae reduced abdominal fat weight ratio (P<0.05). Feeding broilers with three diets, including probiotics of Primalac, Saccharomyces cerevisiae, and Aspergillus oryzae under heat stress, indicated that the weight of carcasses decreased, which could be due to their lack of effect under stress condition (Yaghoobfar et al., 2009). Researches indicated that consumption of lactobacillus reduces abdominal fat in broilers (Kalavathy et al., 2003). A study on the effect of probiotic (Lactobacillus) and synbiotic (Biomin) indicated that the spleen and thymus weight in the chicks consumed probiotic increased at 35 days compared to the group consumed synbiotic , but the weight of the bursa of Fabricius was not changed. According to the results of this study probiotics can affect the organs of the immune system, but their effect can vary, depending on the bacterial strain and the age of the bird (Awad et al., 2009). Non-significant changes for total anti-SRBC, IgG and IgM were observed on day 21 (P>0.05). Administration of 0.3% fermented Saccharomyces cerevisiae increased the total anti-SRBC and IgM on day 28 (P<0.05). Treatments increased total anti-SRBC, 0.3 and 0.5% fermented Saccharomyces cerevisiae increased IgG and 0.1 and 0.3%, increased IgM on day 35 (P<0.05). Total anti-SRBC was increased by 0.3 and 0.5% fermented Saccharomyces cerevisiae and IgG was increased by 0.5% on day 42 (P<0.05). Researchers reported that addition of prebiotics, probiotics or a mixture of these two additives increases the titers of immunoglobulins, which may indicate favorable effects of these additives on immunity of chickens (Ebrahimi et al., 2014). Kabir et al. (2004) reported that the use of Protexin had a positive effect on the immune response of poultry to the SRBC antigen. They generally suggest that the improvement of the immune system under the influence of probiotics is accomplished by increasing general antibodies, increasing macrophage activity, and increasing the production of local antibodies at the mucosal surface of tissues such as the intestinal wall. It was reported that the use of synbiotic Biomin (Hasanpour et al., 2013) and synbiotic Protexin + TechnoMos (Ghahri et al., 2013) increased humoral immune responses. In contrast, it was reported that the use of probiotic BioPlus, prebiotic Biomass and their composition had no effect on serum IgG concentration in broiler chickens (Midilli et al., 2008), the differences between the researchers' findings could be related to the probiotic, prebiotic and synbiotic dose used, the animal species and population studied (age and weight) and microorganism strains. Cellular immunity in response to PHA-p injection was not affected by treatment groups (P>0.05). Diets containing lactobacillus have been shown to improve T lymphocyte function in newly hatched chickens and pullets (Dunham et al., 1993). It was reported that probiotic (Protexin) improved cellular immune function, as well as concomitant use of probiotic and formic acid did not have a synergistic effect on poultry cellular immune system (Mirbabai et al., 2012).

It was concluded that consumption of 0.3% fermented Saccharomyces cerevisiae in broiler diets improved growth performance and humoral immune response.

Guar gum is a galactomannan compound and is anti-nutrient in high amounts and can have prebiotic properties in low amounts in the diet, β-mannanase enzyme reduces its anti-nutrient state by reducing the molecular weight of this compound. Protein is the most expensive component of the diet, which is mostly provided provided by soybean meal in commercial diets. Due to the high cost and limited soybean cultivation area, numerous studies have been carried out on the use of other vegetable meals such as guar meal in chicken nutrition. Cyamopsis tetragonoloba is a drought-tolerant legume that is used primarily in the chewing gum industry because its seeds contain large amounts of guar gum. Guar gum is extracted from the seeds of the guar plant; it is a natural nonionic branched polymer in which the -D-mannopyranosyl unit is attached to 1-4 and the unit a-half pyranosyl unit is used as the side chain takes place. Guar has been used in many applications such as thickeners, ion exchange resins, suspending agents, pharmaceuticals and paper (Wang and Wang, 2009). In order to produce gums, the guar seeds are split, producing a high protein germ fraction and a low protein shell fraction as by-products. These two fractions are typically recombined to produce guar meal with a crude protein level of 35-47.5%, depending on the relative concentrations of the two fractions (Chenault et al., 2002). In addition, approximately 88% of the nitrogen content is true protein, making it possible to use as a component of poultry feed (Lee et al, 2003a). The purpose of this study was to evaluate the different levels of guar gum and with and without addition of β-mannanase enzyme on the performance and immune response of broilers.

For this reason, 312 Ross-308 broiler chickens from 1 to 42 days of age were used based on a completely randomized design with 6 treatments and 4 replicates (13 broiler chicks in each replicate). The six experimental treatments were as follows: corn–soybean meal basal diet:1) control diet, 2) control diet + supplements Fermacto (0.18%), 3) control diet + low gum (0.35%), 4) control diet + high gum (0.70%), 5) control diet + low gum (0.35 percent) + β-mannanase enzyme, 6) control diet + high gum (0.70 percent) + β-mannanase enzyme. Feed intake (FI), body weight gain (BWG) and feed conversion ratio (FCR) were recorded at the end of the period. Two chicks per dietary replicate were injected (32 d.) with either 0.5 mL of 2.5 % SRBC intramuscularly into each breast muscle. Heparinized blood was collected from the wing vein at (39 d.) by venipuncture 6 and 12 d after immunization with SRBC. Samples were frozen at -20°C until analysis. The hemagglutination assays were performed as described by Cheema et al (2003) for RBC. In order to enumerate the Lactobacilli and Escherichia coli on day 42 of breeding period, one chick was selected from each replicate according to protocol described by Corduk et al (2008). The data were analyzed in a completely randomized design by ANOVA using the General Linear Model (GLM) procedure of SAS Institute.

The results showed that the highest feed conversion ratio was seen in high gum 0.70% diet (no- enzyme) and the lowest one was in low gum diet (with enzyme). In agreement with the results of this experiment, Justina et al (2018) showed that chicks fed with high soybean meal and high soybean meal + guar gum diets with added β-mannanase significantly improved blood glucose and anabolic hormone homeostasis, FCR, digestible energy, and digestible amino acids compared to chicks fed with same diets without β-mannanase. The results of this experiment showed that there was no significant difference in IgG and IgM antibody titers between treatments. Unlike our results, the addition of β-mannanase to the enhanced β-galactomannan diet eliminated most of this immune-related signal, indicating that the feed-induced immune response within jejuna was eliminated by the addition of β -mannanase. They also observed changes in specific metabolic and intestinal functional pathways of birds fed β-mannanase. These observed changes in β-mannanase-fed birds may be an enhanced performance and feed conversion mechanism observed in birds given β-mannanase in their diet (Arsenault et al 2017). The reports show that the enzymes be able to accidentally attack the cell wall polymers and thus move to the center of the polymer. Breaking down any polymer chain will significantly reduce the molecular weight of the polymer solution, thereby reducing its anti-nutritional effects (Chacher et al 2017). The dietary β-mannanase had potential to improve daily gain and feed efficiency and apparent ileal digestibility while decreasing digesta viscosity of broiler (Balasubramanian et al 2018). Mannan oligosaccharides bind to type 1 fimbriae to reduce pathogenic bacteria, increase goblet cells, thus, lead to the production of antibacterial mucus and create the conditions for the growth of beneficial bacteria, and eliminates competition. The balance between pathogenic and beneficial bacteria increases the length of the villi and decreases the depth of the crypt, which indicates an improvement in the morphology of the intestine. Improving the morphology of the intestine increases the activity of digestive enzymes and thus increases digestion. In addition, mannan oligosaccharides activate macrophages in intestinal lymphatic tissues, thereby improving cellular and humoral immunity. Mannan oligosaccharides also increase butyric acid production and decrease intestinal pH in broilers. These combined mechanisms promote the growth rate and performance of broilers (Chacher et al 2017).

According to the results, Addition of guar gum and betanamase to the diet had no effect on the performance and immune responses of broilers compared to controls. However, the addition of guar gum with the β-Mannanase enzyme increased the microbial population of jejunum and ileum lactobacilli, therefore, this is also recommended.

Feed shortages as well as the allocation of more than 75 percent of the cost of livestock feed, challenge-where in ensuring animal protein needed by society has created accurate estimation of the nutritional value of animal feeds, especially the use of agricultural waste As a new source of food supply, it can be an important step in meeting the needs of livestock and reducing breeding costs (Nikkhah et al, 1990). Potato plant with a cultivated area of more than 22 million hectares in the world and production of 376 million tons is the number one tuber crop (FAO, 2016). At present, a large amount of potato crop is allocated to animal feed worldwide, approximately 35% of the total potato crop is wasted during processing as waste (Agricultural Report, 2009). These wastes add to environmental problems if not consumed properly. Biotransformation of agricultural wastes and wastes compared to other processing methods increases the nutritional value of the compounds and causes the least pollution to humans, livestock and the environment. On the other hand, it costs less than other methods (Nikkhah and Amanloo, 1992). Large amounts of ruminal contents are produced daily as wastes in slaughterhouses (Said et al, 2015) and are considered environmental pollutants. Abouhief, Kraidees et al. (1999) that the high cost of disposing of these wastes requires a revision of slaughterhouse by-product management (Rincon, Bermudez-Hurtado et al. 2010). Reduces (Cherdthong, Wanapat et al. 2014). Protein is one of the most important factors limiting food intake for ruminants (Mapato, Wanapat et al. 2010). Today, various plant sources (oilseed meal), animal sources (meat powder) and seafood (fish meal) and non-protein nitrogen (urea and slow-release urea) are used to provide the protein needed by livestock. Utilization of non-nitrogen sources Protein reduces the cost of feed consumed in animal feed and improves production efficiency in ruminants (Horn, Telford et al. 1979, Herrera-Saldana and Huber 1989, Gado, Mansour et al. 1998, Holden 1999, Wang, Wu et al. . 2010).Nitroza is a slow-release non-protein nitrogen source for ruminants containing 40% nitrogen, equivalent to 250% crude protein. Nitrogen is a compound with a special structure that causes the slow release of ammonia in the rumen. Fiber-digesting bacteria need a constant amount of ammonia throughout the day (equivalent to 10-15 mg / dL) for their proper growth and function. This amount of ammonia ensures the proper nutrition of bacteria that play an important role in fiber digestion. Ammonia imbalances occur in normal diets. The rumen is deficient at significant hours of the day and at other times has an increase in ammonia. Potato waste is the product of inappropriate environmental conditions, inappropriate harvesting, physiological changes, damage by insects and pests, etc. Potato waste is an ideal substrate for biohydrogen products, and during the simple fermentation process by applying rumen fluid (rumen liquor microorganisms) achieved from the slaughterhouse and adding slow-release urea (Nitroza), it can be assumed as a high protein byproduct. This study is investigating the potential of using rumen liquid microorganisms with slow-release non-protein nitrogen source for bioconversion of potato wastes by measuring CP, N-NH3, VFA, pH, digestibility and nutrient composition in the fermentation medium.

Rumen fluid was obtained from the slaughterhouse (400 mL) and added to potato wastes (200 g) along with different levels (1.5, 3, 4.5 gr) of nitrogen from the Nitroza source and incubated for 24 h at 39 ̊C. Data were analyzed in a completely randomized design (CRD).

Protein content in experimental treatments was significantly (P<0.05) higher than the control group, and the highest level was related to 3 g Nitrogen level (27.223). In the presence of rumen microorganisms, potato wastes with 1.5 g nitrogen from the Nitroza source had the highest digestibility (81.33) during 24 h incubation (P<0.05). The pH of the fermentation medium of the experimental groups ranged from 4.60 to 7.43 for potato waste along with rumen microorganisms group to the added levels of 4.5 g Nitrogen source respectively (P<0.05). In general, based on the results of the present study, rumen liquid microorganisms along with Nitroza as a non-protein nitrogen source can be used in bio-conversion of potato waste to increase nutritional value and nutrient composition. The results of Swingersren et al. (2007) showed that more than half of the raw potatoes remained non-degradable after 5 hours of incubation with ruminal fluid. In vitro disappearance of dry matter and organic matter of potato, skin lesions were reported to be 85.38% and 88.7% and it is probable that these results are slightly dependent on crude fiber (Horn et al. 1979) and digestion rate is more related to starch (Gado et al. 1998). 1 gram of nitrogen from nitrogen may be related to the supply of sufficient ammonia from Nitroza and increase digestion. The results of the study of the effect of various additives including nitrogen on the disappearance of dry matter using the Holden method are reported in Table 5.

Based on the results, adding different sources of nitrogen had a significant effect on food digestibility (p<0.05). According to the results, it can be said that using ruminal microorganisms for bioconversion of potato waste along with supplementation with different levels of non-protein nitrogen sources, including nitrogen, significantly increased the nutritional value of potato waste, which thus in addition to the use of various sources of non-protein nitrogen, research can be done on agricultural wastes that have no marketability and its disposal to the environment causes many problems, slaughterhouse waste. Which are environmentally polluting and used the resulting substance in the diet of ruminants.

Milking activity is one of the most important daily activities in industrial dairy farms, which accounts for about 80 percent of the annual milking costs and more than 50 percent of the daily activities of each dairy farm. Milking speed (MS) is an important functional trait to dairy producers and in few countries (e.g. Canada), MS have been recorded for several years by milk recording agencies. Functional traits include traits related to animal health, feed efficiency, milkability, and calving ease. Milkability is the ease of milking in dairy cows (Gäde 2007). One of the important traits related to milkability is milking speed and usually, milkability is evaluated by measuring this trait (Gray et al. 2012). Milking speed refers to the amount of milk released from the mammary glands per minute (Klindworth 2003). Due to the effect of milking speed on udder health and labor productivity, this trait is considered a very important one from an economic point of view and has been emphasized in dairy cow selection programs for many years (Karacaören et al. 2006). However, there is evidence that increasing of milking speed is associated with increasing of udder health problems such as mastitis, and as a result, the optimal milking speed is considered by breeders. Milking speed can be assessed based on two indicators; 1) Scoring based on 1 to 5 points and 2) Using electronic stopwatch and flowmeter. The advantage of using a stopwatch is that it is being used easier than a flowmeter and the duration of its use is being reduced, However, the need for a technician to be present during milking is a major drawback of this method (Beard, K. 1993). This study aimed to estimate genetic parameters for milking speed and association between milking speed and milk components (somatic cell score, protein percentage, and fat percentage), in Holstein dairy cows in Isfahan province, Iran.

Data were 5292 observations related to 1762 cows in 7 herds of Holstein dairy cows in Isfahan between October 2015 and April 2016. The distribution of MS scores was skewed toward faster milking speeds. Milk components data, including fat percentage, protein percentage and somatic cell count, belong to the same date, was obtained from the Isfahan Farmers' Cooperative (Vahdat). Only herds with complete pedigree information and three milkings records per day were selectected for final dataset. The milking time of each animal was measured by using a stopwatch and recorded in the form. Data editing quality control was performed by using Excel (2013) and FoxPro 9.0. The average milking flow rate criterion(amount of produced milk in kilograms divided by the milking time in minutes) was used to evaluate the trait of milking speed. To generate data with normal distribution, the somatic cell count (SCC) was transformed to somatic cell score (SCS) by natural logarithmic conversion. Pedigree was traced back to the founder generation. (Co)variance components were estimated using a DMU software package with an average-information (AI)-REML algorithm for the analysis of multivariate mixed models (Madsen and Jensen, 2013).Genetic evaluations and Best Linear Unbiasd Prediction (BLUP) of breeding values for milking speed was computed with the animal model by DMU program.

The results of the analysis of variance showed that the effects of herd, milking frequency, parity, and stage of lactation on milking speed were significant (p <0.01) and remained in the model. However, the effect of age at the first calving on this trait was not significant (p > 0.05). Mean of milking speed of the animals in this study was 1.96 ± 0.75 kg/min, and the least square means of milking speed in the population was 2.11 (±0.01) kg/min. The highest least square means of milking speed belonged to the third-parity cows with a mean of 2/21 (±0.01) kg/min and the least square means of milking speed belonged to the primiparous cows with mean of 1/98 (±0.02). Older cows have higher-capacity gland cisterns, and consequently, their cisterns can store more milk than the cisterns of primiparous cows. More milk stored in the cisterns can put more pressure on the teat sphincter and escape more quickly. By stages of lactation, the highest least square means of milking speed was observed in group 4 (the cows in the 51 to 65 DIM) with mean of 2/32 (±0.05) kg/min which can be due to the location of the animal in its milk yield peak. Also, the lowest least square means of milking speed was related to group 15 (the cows in the 321 to 350) with mean of 1.79 (±0.04) kg/min. In late lacataion stage, the amount of milk produced by the cow will reach the lowest possible level during its lactation stage. The estimated heritability of the milking speed in this study was 0.22 (±0.06). The results of this study showed that the traits related to milkability have moderate heritability. A high genetic correlation was observed between milking speed and milk yield (0.90) and milking time (-0.83). The estimated genetic correlation between milking speed with fat percentage and protein percentage was high and negative, -0.69 and -0.47, respectively. In this study, the estimated genetic correlation between milking speed and somatic cell score showed that selecting to increase the milking speed would reduce the somatic cell count. In general, Genetic evaluations for MS can provide useful information for breeding decisions because of the moderate heritability of MS.

Milking speed has a moderate heritability that allows selection to improve this trait in breeding programs.

A The use of vitamin C in conditions of heat stress and poultry rejuvenation compared to this stressor has been recorded by researchers for many years (Nameghi 1386). . The experiment was a completely randomized design with 7 treatments and 4 replications, 10 birds each. Treatments included: control diet, 3 level of vitamin C (0, 100 and 200 mg/kg) and 3 level of Nano vitamin C (0, 100 and 200 mg/kg). The experimental diets were based on corn and soybean. During the experiment, water and food were offered ad libitum. Body weight and feed intake at the end of each period were measured and used to calculate body weight gain and feed conversion ratio. At d 42 one bird from each replicate was selected and killed to measure the internal organ weights. Also, the weight and length of the jejunum were calculated, and partly for intestinal morphology in formalin 10%.

The effect of dietary treatments on feed consumption in broiler chickens was significant (P<0.05). Chickens that received 200 mg of vitamin C kg-1 diet had the greatest feed intake than other chicks. The results of this study was in line with the results of Kutlu and Forbes (1993) who reported that 250 mgof vitamin C increased these parameters. Experimental treatments had a significant effect on the weight gain of chicks (P<0.001). Chickens that received 50 mg nano vitamin C had the greatest weight gain compared to other treatments. According to these results, Roshani et al. (2006) reported that vitamin C during the stress period improved the feed intake and daily weight gain. Sahin and Kucuk (2002) reported that the use of 200 mg vitamin C /kg of diet improved the feed intake of quails under stress conditions. Gross (1988) showed that vitamin C under stress conditions caused an increase in daily weight gain in broiler chicks. In another study, Ping et al. (2011) showed that nano multivitamin improved weight gain, feed intake and reduced mortality. Chicks fed 50 mg nano vitamin C had the best conversion ratio compared to other treatments. The results of this experiment are consistent with the results of Alba et al. (1393), Kutlu and Forbes (1993), and Amakye et al. (2000). They reported that the use of vitamin C supplementation significantly reduced the feed conversion ratio compared to the control group. Sahin and Kucuk (2002) reported that using 200 mg/kg of vitamin C improved feed consumption and feed conversion ratio under heat stress. Researchers reported that vitamin C supplementation in summer did not have a significant effect on the relative weight of the thigh, which is similar to the results of this experiment (Konca, 2009). Relative weight of breast and carcass was affected by experimental treatments and a significant difference was observed between the groups. The greatest relative weight of the carcass was related to birds received 200 mg vitamin C kg-1 diet. The greatest relative weight was related to treatment with 50 mg nano vitamin C. According to these results, Sahin et al. (2002) reported that vitamin C supplementation of 250 mg/kg of diet improved live weight, nutritional efficiency and carcass traits. Also, Roshani et al. (2006) reported that vitamin C supplementation during the stressful period significantly increased the weight of the chest. Rafie et al. (1393) reported that 250 mg/kg vitamin C increased breast weight and could somewhat reduce the negative effects of heat stress. Darmankouhi (2005) reported that ascorbic acid increased the carcass quality and yield under heat stress conditions. Relative weight of liver was not affected by experimental treatments. The effect of treatments on relative weight of spleen was significant (P<0.05). Chickens fed 100 mg of vitamin C had the greatest relative spleen weight. An experiment showed that vitamin C had no significant effect on different gastrointestinal system (Konca, 2009). Nemati et al. (1392) reported that the use of antioxidants such as vitamin C under stress conditions, reduced spleen relative weight, immune system, and mortality. Raeisi et al. (1394) showed that the effect of different levels of vitamin C on the relative weight of the spleen and liver was significant. The greatest amount of relative length of jejunum was belonged to birds received 100 mg of nano vitamin C. This level was significantly different from that of the control group and 50 mg vitamin C (P<0.05). The relative weight of the jejunum was not affected by the treatments. Treatments did not have a significant effect on white blood cells. The greatest amount of RBC was related to treatment with 200 mg nano vitamin C (P<0.05). This treatment was significantly different from control treatments, 50 mg vitamin C, 50 mg nano-vitamin C and 100 mg vitamin C (P<0.001). The greatest amount of hemoglobin was related to the level of 200 mg nano vitamin C (P<0.001). The experimental treatments did not have any effect on the heterophile levels. The greatest amount of lymphocyte was related to birds fed 50 mg and 100 mg nano vitamin C(P<0.001), which had a significant difference with 200 mg vitamin C and nano vitamin C (P<0.05). Gross (1988) showed that the number of lymphocytes was increased by the use of vitamin C in broiler diets. Taghilu et al. (1389) showed that 0.05% of vitamin C improved hematocrit. Regarding the effect of vitamin C, Tuleun et al. (2011) showed that vitamin C had no significant effect on blood cell parameters. In another study Mirzapoor et al. (1394) examined levels of 250 and 500 mg of vitamin C on blood parameters. Results showed that vitamin C increased the amount of red blood cells and hemoglobin and improved hematocrit of the blood.The greatest amount of glutathione peroxidase enzyme was related to the level of 200 mg nano vitamin C kg-1 diet(P<0.001), which was significantly different from other treatments. Research has shown that vitamin C has an electron capability that acts as a regenerator of active oxygen species (ROS) and has a moderating role in the antioxidant defense activity (Sies et al. 1995). Chickens that received different levels of vitamin C and nano vitamin C had a significant difference compared to the control group (Data was not shown in this article).. Rafiei et al. (1393) showed that lemon powder with 250 mg/kg of vitamin C reduces the negative effects of heat stress and improves the immune response of the bird. Pardu et al. (1985) reported that the consumption of 1000 mg/kg of vitamin C would increase antibody production against SRBC. Mccorre et al. (1980) showed that ascorbic acid can increase the activity of B lymphocytes improving humoral immune responses. Amakye et al., reported vitamin C improve humoral immune response in broiler chicks.

The results of this experiment showed that consumption of 50 mg nano vitamin C kg-1 diet had a positive effect on growth performance of broiler chicks, thus improving the weight gain and feed conversion ratio. Also increased the weight of the liver, spleen and bursa, and improved immune function and the rate of humoral immune response. Also, 200 milligrams of nano-vitamin C kg-1 diet increased the concentration of hemoglobin and glutathione peroxidase enzyme under heat stress conditions.

A significant portion of livestock feed resources are roughage and fibrous in Iran, which is low in protein, minerals, and digestible energy; however, if treated by some methods, has the potential to be used as an energy source in livestock diets (Adesogan et al. 2019). There are 10 sugarcane development companies in Khuzestan province, which have 127,000 hectares under sugarcane cultivation and the area under sugarcane cultivation is 100,000 hectares per year (FAOSTAT 2013). Sugarcane is harvested in two ways: black (burning) and green (harvesting with a harvester). About 15 to 25 percent of the weight of sugarcane includes leaves and branches named sugarcane top, so the green harvesting produces about 20000 kg of wet biomass per hectare (Moradi et al. 2019). Due to the area under sugarcane cultivation in the Khuzestan province, and its 50% humidity, about two million tons of sugarcane top is produced each year. During harvesting, the sugarcane residues remain on the ground and cause special problems for the maintenance operation of the sugarcane on the field, so the residue is burned in two stages before and after harvesting, and it pollutes the environment, especially the air (Kingston et al. 2005). If the sugarcane top residues treated, due to breakdown of lignocellulose structure and degradation of lignin, cased to the increased access of ruminal microorganisms to lignosullose materials, so instead of burning, they can be used as fodder sources in animal feeding (Karp et al. 2013). Therefore, the aim of present experiment was conducted to evaluate the effects of steam and alkaline hydrogen peroxide treatment to improve the nutritional value of sugarcane top for fattening lambs.

The present experiment was performed in Agricultural Sciences and Natural Resources University of Khuzestan. The sugarcane top used in the present experiment was from variety of CP73 and CP57 harvested from Imam Khomeini agro-industry company of Shushtar. After the sugarcane was harvested, it was dried and chopped into 2 to 3 cm long with a chopper and transferred to the Shoaibiyeh Livestock Feed Company for steam treatment. Steam was conducted at 184ᵒC for 4 minutes; the equal pressure was 16 to 18 atm. (average 17 atm.). The sugarcane top was treated using a solution of 1% hydrogen peroxide, which pH was adjusted to 11.5 using a solution of sodium hydroxide (alkaline hydrogen peroxide). Twenty-four Arabi male lambs with average live weight of 30.4 ± 5 kg were used in a completely randomized design with 3 treatments and 8 replicates for a period of 70 days. Experimental treatments were: 1- control (untreated Sugarcane top), 2- diet containing steam treated Sugarcane top, and 3- diet containing steam and alkaline hydrogen peroxide treated sugarcane top.

Treatment with steam and alkaline hydrogen peroxide significantly reduced the percentage of NDF, ADF, crude fiber, lignin, and increased the significance of the gross energy of sugarcane (P <0.05), but had no effect on crude protein. In consistent with the results of the present experiment, other researchers also reported a decrease in dry matter, NDF, and ADF by applying water vapor under pressure. The decrease of these nutrients has been attributed to the fragmentation or hydrolysis of all or part of the hemicellulose. In compared to control, average feed intake, digestibility of nutrients, final weight, average daily gain, feed efficiency of lambs, rumen propionate and total volatile fatty acids, and blood glucose were increased with feeding of treated sugarcane top, and treatment 3 shown the best results (P<0.05). The components of the experimental diets are the same, and the only difference was in the type of treatments. Therefore, perhaps the reason for the increase in feed consumption in treatments containing sugarcane top treated with steam or steam and alkaline hydrogen peroxide is to improve its digestibility. Increasing digestibility will cause the material to pass through the rumen faster and thus animals consume more feed. The concentration of alanine transaminase was decreased, because of treatment of sugarcane top (P<0.05). The concentration of rumen ammonia nitrogen and pH, blood aspartate transaminase, and carcass traits were not affected by the treatments. Therefore, treatment by steam and alkaline hydrogen peroxide caused to improve the nutritional value of sugarcane top, and their combined use (third treatment) showed better results.

Treatment with steam and alkaline hydrogen peroxide significantly reduced the percentage of NDF, ADF, crude fiber, lignin, and increased the significance of the gross energy of sugarcane (P <0.05), but had no effect on crude protein. In consistent with the results of the present experiment, other researchers also reported a decrease in dry matter, NDF, and ADF by applying water vapor under pressure. The decrease of these nutrients has been attributed to the fragmentation or hydrolysis of all or part of the hemicellulose. In compared to control, average feed intake, digestibility of nutrients, final weight, average daily gain, feed efficiency of lambs, rumen propionate and total volatile fatty acids, and blood glucose were increased with feeding of treated sugarcane top, and treatment 3 shown the best results (P<0.05). The components of the experimental diets are the same, and the only difference was in the type of treatments. Therefore, perhaps the reason for the increase in feed consumption in treatments containing sugarcane top treated with steam or steam and alkaline hydrogen peroxide is to improve its digestibility. Increasing digestibility will cause the material to pass through the rumen faster and thus animals consume more feed. The concentration of alanine transaminase was decreased, because of treatment of sugarcane top (P<0.05). The concentration of rumen ammonia nitrogen and pH, blood aspartate transaminase, and carcass traits were not affected by the treatments. Therefore, treatment by steam and alkaline hydrogen peroxide caused to improve the nutritional value of sugarcane top, and their combined use (third treatment) showed better results.

The main challenge of breeding broiler chicken breeders is to increase the production of fertile eggs. About 70% of the decline in production during different stages of incubation is due to infertile eggs and fetal mortality. The fertility reduction in male broiler breeders after 50 weeks has been reported as the major reason for production loss. This reduction can be attributed to different factors, such as age, weight, and low semen quality. The composition of seminal long chain fatty acids (FA) is affected by the diet. Thus, a diet enriched with n-3 and n-6 FAs can alter the proportion of fatty acids in the sperm and semen plasma. The amount of n-6 FAs in the sperm membrane phospholipid increased as a result of the consumption of a commercial diet.
The phospholipid of the bird sperm is identified with a very high amount of C20-22n-6 (PUFA). The increased amount of n-3 FAs in poultry sperm has a positive effect on the quality of sperm and fertility, which leads to increased sperm motility in the oviduct and fertilization. Flaxseed is the richest dietary source of n-3 FAs, i.e. α-linolenic acid, and lignan. Flaxseed dietary increases the amount of n-3 FAs (PUFA) in the phospholipid membrane of the sperm body, while it decreases n-6 FAs in the membrane of the sperm head and the ratio of n-3:n-6. In addition, the sperm motility has a positive correlation with the amount of phospholipid and a negative correlation with the amount of free cholesterol. The ability to synthesize C20-22 polyunsaturated FAs is decreased in phospholipids with age. Thus, the inclusion of α-linolenic acid in the diet of male birds results in an accurate balance of n-6/n-3 and a rise in the ratio of phospholipid/cholesterol, which would lead to a potential dramatic change in the fertility. The present study was aimed to investigate the effects of dietary flaxseed on the sperm quality and fertility of broiler breeder roosters.

This research was conducted on the broiler chicken farm of Kimiaparvar Company. Three experimental diets were tested on 1920 Ross 308 roosters which were located in six halls. Therefore, there were two halls for each experimental diet. The first phase were performed on the 33-41 weeks old birds, after their peak of production and the second phase was continued from 53 until 61 weeks of age. The experimental diets were as follows: control diet, which was formulated based on corn-soybean oil (n-6 FAs-rich), a diet with 0.2% omega-3 (n-3 FAs-rich (Pepin)), and a diet that contained 2% whole grain flaxseed. Five birds from each hall (n=30 in total) were randomly labeled for weighing, blood and sperm sampling. The blood tests, such as glucose, cholesterol, triglyceride and urea were performed using the spectrophotometry technique. The evaluation of sperm parameters and the analysis of fatty acids were conducted by the CASA system and the chromatography method, respectively. The labelled birds were trained for semen collection over three weeks using the method of abdominal message. The semen was collected once a week from week 57 to week 61. The collected samples from 5 birds were pooled before the analysis. In week 61th, the testicles of the birds were weighed after slaughter. In addition, the percentage of fertile and infertile eggs was calculated during the period. The birds were weighed from 33-61 weeks. The evaluation of sperm characteristics included: straight-liner velocity (VSL, µm/s), curvilinear velocity (VCL, µm/s), VAP: average path velocity (VAP, µm/s), linearity (LIN, %), wobble (WOB, %), straightness (STR, %), beat cross frequency (BCF, HZ), lateral head displacement (ALH, micron), mean angle degree (MAD, deg), progressive motility (PM, %), none progressive motility (NPM, %), immotile (IM, %), and concentration (M/ml).

The dietary treatments had no significant effect on the blood parameters and the weight of testicles. Similarly, in a study adding 3% of fish oil in the diet of broiler breeder roosters did not change the testicular weight. The overall effect of dietary treatments in CASA data and motility parameters was non-significant. This is consistent with the previous studies, which showed that diets with different sources of fats have no effect on the sperm motility parameters. It has been reported that the flaxseed oil had no effect on the volume and concentration of semen.According to our analysis, the dietary treatments increased the number of fertile eggs. The percentage of fertile eggs in the flaxseed group was significantly higher than the pepin and the control groups. However, there was no significant difference in the number of fertile eggs between the pepin and the control treatments. The researches confirmed that reducing the ratio of n-6/n-3 in rooster sperm by adding α-linolenic acid sources leads to increased fertility. The treatment and age had significant impacts on the body weight of the birds, where the lowest body weight was from the group that received the flaxseed diet. This could be beneficial for the producers as weight gain leads to reduced fertility in broiler breeders.The biological studies on the fertility of birds have shown that the lipid composition is the main determinant of the required flexibility of the membrane for the flagellar movement and the penetration ability of the sperm, which would facilitate the acrosome activity and the fertilization.

Manipulation of the phospholipid fatty acids of the sperm membrane with the enriched n-3 fatty acids diet improves the fertility in roosters. Our weekly results indicate a significant improvement in the motion parameters and the quantity of sperms over some weeks during the study. This effect coincides with a significant increase in the number of fertile eggs in the flaxseed group. The flaxseed as an easy available and cheap source of n-3 FAs and lignans has more significant effects on the fertility compared with the fish oil, which is more expensive. Therefore, the whole flaxseed is an ideal dietary supplement for the broiler breeder roosters, especially for the old flocks.