فصلنامه پژوهشهای تولیدات دامی
پیاپی 30 (زمستان 1399)

The present study was performed to investigate the effects of dietary organic and inorganic selenium on the quality of frozen-thawed semen of broiler breeder cockerel under oxidative stress. In this experiment, a total of 24, 28-week-old Ross 308 cockerels were allocated into 4 treatments each of which had 6 birds, in a completely randomized design. Experimental groups were: 1) control group (CON): basal diet without selenium supplementation or dexamethasone administration, 2) DEX group: birds consumed the basal diet with dexamethasone injection (4 mg/Kg body weight, three times, every other day for 1 week), 3) DEX(OSe) group: addition of 0.3 mg selenium per kilogram of diet from selenomethionine as organic selenium to the basal diet of birds administrated dexamethasone like group 2 and 4) DEX(ISe) group: similar to group 3 but selenite sodium as an inorganic source was added to the diet. After semen collection, the semen was frozen by modified Beltsvile extender. Sperm evaluation was carried out by the Computer-Assisted Sperm Analysis system (CASA) in thawed semen. Results showed that the addition of organic selenium to the diet of stressed birds (DEX(OSe)) improved total and progressive motility versus other experimental groups (P<0.05); although, DEX(OSe) was not statistically different with CON in progressive motility (P>0.05). Also, the addition of inorganic selenium in the diet of stressed birds (DEX(ISe)) did not improve the mentioned parameters versus DEX (P>0.05). On the other hand, not only the viability and membrane integrity of sperm but also biochemical parameters (glutathione peroxidase and superoxide dismutase) of DEX(OSe) were higher than other experimental groups (P<0.05). It seems, the addition of organic selenium in the diet of cockerel under physiologic stress results in higher sperm quality than inorganic selenium.

Ursolic acid (UA) is known as a naturally occurring triterpene pentacyclic compound in some medicinal herbs including savory that affects the skeletal muscle. In the current study, the effect of UA was evaluated on C2C12 cells and satellite cells (SCs) isolated from native broiler chicks. First in the in vitro experiment, the C2C12 cell line obtained from the Stem Cell Technology Research Center and the SCs were isolated and purified from one-day chickens and then treated with UA. In the in vivo experiment, UA was injected intramuscularly based on the body weight to chicks during the first seven days, two times a day, from day one to day seven by the appropriate dose obtained in the in vitro experiment, and then SCs were isolated from pectoralis muscle at the last day. The purification was confirmed by assessment of PAX-7 expression in both in vitro and in vivo experiments. In fact, SCs and C2C12 cells were cultured for seven days in 10% serum medium with vehicle alone (0.1% DMSO) or UA (0.00025, 0.0005, 0.001, 0.0015 and 0.002 mg/mL) along with DMSO (1 mL). The findings from the in vitro and in vivo experiments revealed that UA at 0.00025 mg/mL significantly increased the expression of genes involved in the SCs proliferation and differentiation including PAX-7, MyoD and Myogenin, and improve the muscle hypertrophy. As a result, UA can be suggested as a suitable material to reduce the breeding period and faster growth of skeletal muscle in broiler chickens.

The present study was performed to investigate the effects of dietary electrolyte balance and probiotic on the performance and carcass characteristics in Japanese quail under heat stress conditions. A total of 672 quail chicks (20-day old) were studied in a three-factor, factorial experiment with 4 replicates and in each replication of 14 birds during 20 to 37 and 20 to 41 days Factors included three levels of dietary electrolyte balance (DEB) (170, 220 and 270 mEq / kg), two levels of probiotic protexin (0 and 100 g / t) and two temperature levels (normal rearing temperature and 34 ° C). The effect of sex was also considered as one of the factors for carcass evaluation. Results showed that probiotic-fed birds at age 20 to 37 had the highest feed intake, while the best feed conversion ratio was obtained without probiotic (P<0.05). During 20 to 37 and 20 to 41 days under heat stress conditions, the best feed conversion ratio and weight gain were related to DEB 270 mEq / kg and no probiotic treatment. Under normal temperature conditions, the best conversion ratio and weight gain coefficients in each time period were related to the diet without probiotics and DEB 170 mEq / kg (P<0.05). The use of probiotic had a significant effect on the relative weight of the carcass and the relative weight of the heart (P<0.05). Also, within each genus, the highest carcass weight and percentage belonged to probiotic treatments (P<0.05). Interactions between probiotics, temperature and sex in males showed significantly (P<0.05) higher relative weight in carcass traits. In general, the use of 170 mEq / kg is recommended for electrolyte balance under normal temperature conditions. Probiotics can be used to achieve the best carcass efficiency.

The aim of this study was to investigate the effects of extruded flaxseed and conjugated linoleic acid on growth performance, blood parameters in Holstein suckling calves. This experiment was carried out with 30 newborn Holstein calves with an average age of 1-8 days, and about 36±2 kg body weight, with 6 treatments and 5 replications in a completely randomized factorial design (3×2). The treatments included: 1) Basal diet (control), (2) Basal diet with 3% flaxseed extruded and without conjugated linoleic acid, (3) Basal diet with 3% extruded flaxseed, and 10 g of conjugated linoleic acid, (4) Basal diet with 6% flaxseed extruded and without conjugated linoleic acid, 5) Basal diet with 6% flaxseed extruded and 10 g without conjugated linoleic acid, and 6) Basal diet with 10 g conjugated linoleic acid without extruded flaxseed. The calves were housed in individual pens and fed with whole milk approximately at 10% of birth weight and they had free access to the feed starter and water. Blood samples were collected from the jugular vein on the 30 and 75 day of the trial. Also, growth performance and feed conversion ratio were calculated. The results showed that final weight was affected by extruded flaxseed (P =0514). While conjugated linoleic acid and their interacting was not affected on final weight. The results showed that adding conjugated linoleic acid and extruded flax in starter calves had not significant effect on daily gain in the first and second months and whole period. Daily feed intake was not affected by experimental treatments in the first and second months and whole periods. Blood parameters (glucose, cholesterol, total protein, albumin and triglyceride), and skeletal growth parameters were not affected by adding conjugated linoleic acid and extruded flaxseed. Based on the results of this study, supplementation of extruded flaxseed could not improve growth performance, skeletal growth and blood parameters.

This study was conducted to investigate the effect of canola seed (raw and roasted) and diet concentrate levels on growth performance and quantitative and qualitative characteristics of carcass of Lori male lambs. A total of 54 male 30±0.86kg lambs were selected for the experiment. Treatments consisted of two levels of canola seed (raw and roasted) and three levels of concentrate (60, 70 and 80%). The experiment was conducted as factorial with completely randomized design (2 × 3) with three replicates (each replicate containing 3 lambs). The effect of canola seed (raw and roasted) and diet concentrate level on weight gain and feed conversion ratio were significant (P<0.05). The most daily gain and the bet feed conversion ratio were 230g and 5.52 in lambs fed with roasted canola seed and 70% concentrate, respectively.  The canola seed (raw and roasted) and diet concentrate had a significant effect on lean meat percentage, total carcass fat percentage and cold and hot carcass percentage (P<0.05). The highest carcass yield, cold carcass weight, carcass and meat percentage were related to lamb fed with roasted canola seed and 70% concentrate (P<0.05). The production cost per kg of live weight, cost per kg of carcass and lean meat in lambs fed roasted canola seed and 70% concentrate were lower than other treatments. The results showed that the qualitative characteristics including pH, chemical composition and color of meat were not affected by diets.  The results of this study showed that the treatment of roasted canola seeds and 70% concentrate was superior to other treatments due to higher performance characteristics and better carcass traits.

This study was performed to investigate the effect of different levels of potato in the diet on ruminal parameters, nutrient digestibility and rumen liquor cellulolytic enzymes including microcrystalline-cellulase and carboxymethyl-cellulase in different parts of rumen liquor (particulate material (PM), extra cellular (EC) or cellular. Twelve Dalagh ewes were used in this experiment in a completely randomized design with 3 treatments and 4 replicates. Experimental treatments included 1) control treatment (no potatoes) 2) 7.5% potato treatment 3) 15% potato treatment based on dietary dry matter. The diets were similar in protein and energy. The results of this study showed that the difference in pH of rumen liquor between treatments (6.02-6.4) was statistically significant (p=0.0003). Among the experimental treatments, the highest amount of rumen ammonia nitrogen was observe in the control treatment (14.93) and the lowest in the treatment containing 15% potato (10.23) and the difference was statistically significant (p= 0.0001).The number of protozoa in the control treatments was the lowest and the potato treatment 7.5% the highest .This difference was significant between control treatment and treatments containing 7.5 and 15% potatoes (p=0.023). The DDM, CP, OM, NDF digestibility of diet in three rations did differ significantly (p =0.0001). Among the activities of carboxymethyl-cellulase and microcrystalline-cellulase enzymes in the cellular, EC, PM and total fraction (all 3 sections), the highest and lowest values were observed in control and 15% potato treatments, respectively. There was a significant difference between the three treatment (p<0.0001). According to the results mentioned, potato can be used up to 15% of the diet of ewes without any adverse effect.

The aim of this study was to evaluate the in vitro effect of coating soybean meal and canola meal with different fat sources on ruminal degradability and intestinal digestibility, as well as, the in vivo digestibility. For this purpose, calcium salt of omega-3, calcium salts of unsaturated fatty acids and prilled fat were used for coating. To determine ruminal degradability, three lactating Holsteins cows fitted with rumen fistulas were used and ruminal degradability and intestinal digestibility of dry matter and crude protein were measured. In the in vivo experiment, 40 Holstein cows were randomly assigned to five treatments (control, full fat soybean, soybean-omega3, soybean-ca salt and soybean-prilled fat). The results of the present study showed that coating soybean meal and canola meal with different fats reduced the degradability of dry matter and protein in the rumen and increased their digestibility in the intestine (p <0.0001). It was also shown that protection of soybean meal with prilled fat and calcium salts of unsaturated fatty acids was better than omega 3, but coating of canola meal with calcium salt and omega 3 fats was better than prilled fat (p <0.05). The results of in vitro experiment showed that omega-3 coated soybean meal had the highest digestibility (p=0.009). It can be concluded that coating protein meal with fat will transfer protein digestion from rumen to intestine and thus increase the RUP portion of protein meal.

Evidence from animal studies suggests corticotrophin and melanocortin systems have regulatory role in feeding system in avian, but there is no evidence for their interaction. In this survey three experiments designed to investigate the role of corticotrophin receptors on food intake using melanocortin receptors agonist M3 and M4 in neonatal chicken (each experiment includes 4 groups and 11 birds in each group). In experiment 1, chickens were intracerebroventricularly (ICV) injected with control solution, MTII (MC3/MC4 receptors agonist; 2.45, 4.8 and 9.8 pmol). In experiment 2, control solution, MTII (9.8 pmol), astressin-B (CRF1/ CRF2 receptors antagonist; 30 µg), and MTII + astressin-B were injected. In experiment 3, control solution, MTII (9.8 pmol), astressin-2B (CRF2 receptors antagonist; 30 µg), and MTII + astressin-2B were injected. Then, cumulative feed intake was recorded until 120 min after injection. According to the results, dose dependent hypophagia observed after ICV injection of the MTII (p<0.05). ICV injection of MTII (9.8 pmol) + astressin-B had no effect on the hypophagic effect of the MTII (p> 0.05). ICV injection of MTII (9.8 pmol) + astressin-2B significnatly diminished MTII-induced hypophagia (p<0.05). These results suggest that inducing hypophagia by melanocortin mediates via corticotropin CRF2 receptors in broiler chicken.

This study was conducted to determine the effects of Bitter Orange blossom powder (BOBP) on growth performance, carcass characteristics and some blood parameters in broiler chickens under heat stress condition. A total of 200 one day-old male broiler chicks (Ross 308) randomly were divided into five treatment groups in a completely randomized design with four replicates of 10 birds each. The experimental treatments including control (basal diet), the basal diet with Neomycin (0.2% of v diet) and 3 levels of BOBP (0.5, 1 and 2% of diet). Birds submitted to heat stress (32±2ºC from 10.00 AM to 6.00 PM) from 15 to 42 d of age. Blood samples were taken from 8 birds per treatment at the end of experiment. The results showed that, average mortality was significantly lower (P<0.05) in treatments groups (3.75%) than in the control group (22.5%). The diet supplemented with BOBP had no effects on feed intake and weight gain of chicks during different periods (P>0.05). In the grower phase (11-24 d), the lowest fed conversion ratio (FCR) was obtained in 0.5% BOBP, which were significantly different from 2% treatment (P<0.05). Birds receiving diet supplemented with 1% BOBP revealed significantly (P<0.05) lower blood glucose compared to the control group (211 vs 225.8 mg/dl). LDL level was lower (p < 0.05) in 2% BOBP treatment (57.4 mL/dL) compared to 0.5% (69.6 mg/dl). The feeding of BOBP did not induce any significant effect on the whole carcass, breast, drumstick and internal organs weight of broiler chickens (P<0.05). In conclusion, BOBP may be effective in attenuating heat stress effects due to its illustrated antioxidant effects.

Cottonseed meal was hydrolyzed using five types of enzymes: alkalase, chymotrypsin, pepsin, trypsin, and pancreatin. The experiment was carried out using 240 male broilers of Ross 308 strain in a completely randomized design with 4 treatments and 5 replications from 1 to 35 days of age and during the starter (1-15 days) and grower (16-35 days) phases. The experimental diets were the control diet, the control diet containing zinc bacitracin (70 mg/kg), and the experimental diets containing 15 or 20 g/kg cottonseed bioactive peptides which replaced equal amounts of corn and Soybean in the diet. Feed intake, weight gain and feed conversion ratio were measured and calculated for each cage (repetition) during three rearing (starter, grower and total period). At 35 days of age, 3 ml blood was obtained from the wing vein of 3 birds per replicate to measure serum antioxidant parameters. At the end of the rearing period, three birds from each cage were individually weighed and slaughtered and the relative weights of carcass, gastrointestinal and lymphoid organs as well as the length of different parts of the small intestine were measured. In the whole of the experimental period, the highest and lowest weight gain was observed in the antibiotic and the control groups, respectively. Antibiotic and peptide fed groups had higher feed intake and feed conversion ratio than the control group. Serum nitric oxide levels were higher in the 15 g/kg peptide group than in the control group and the antibiotic group. Malondialdehyde levels were lower for antibiotic or peptide groups than in the control group, and glutathione peroxidase levels in the groups fed antibiotic or 15 g/kg peptide was higher than in two other groups. Serum superoxide dismutase levels were higher in the groups receiving antibiotics or different levels of peptide than in the control group and the total serum antioxidant levels were not affected by the experimental diets. Antibiotic or peptide administration significantly reduced abdominal fat compared with the control group. The results of the present study showed that the bioactive peptides produced by enzymatic hydrolysis of cottonseed meal improved the growth efficiency and antioxidant parameters of broiler chickens. These results suggest that the bioactive peptides of cottonseed meal have the potential to be used as an alternative to growth-promoting antibiotics in the broiler chickens diets.

Gonadotropin-releasing hormone (GnRH) is a key regulatory molecule of the hypothalamus–pituitary gonadal axis which induces transcription of luteinizing hormone (LH) from the anterior pituitary. Research has shown that estrogen plays an important role in regulating GnRH. Also, recent experiments indicated that Vitex agnus-castus (VAC) has high levels of phytoestrogen. Hence, this research was performed to investigate the effect of Vitex Agnuse Castus (VAC) fruit powder on GnRH and LH genes expression in laying hens using Real time qPCR technique. For this purpose, 90 Hy-line W-36 leghorn (at 72 to 80 weeks old) were used in a completely randomized design with 3 treatments, 5 replicates and 6 hens per replicate for 56 days as an experimental period. The three experimental treatments were: 1- control diet (basal diet without any additives), 2- basal diet plus 1% VAC fruit powder, 3- Basal diet plus 2% VAC fruit powder. At the end of the experiment one hens were slaughtered and their hypothalamus was rapidly separated and transferred to the laboratory with liquid nitrogen. Then, RNA was extracted and used for cDNA synthesis. Finally, GnRH gene expression was evaluated by Real-Time qPCR. The ANOVA results showed that GnRH gene expression was significantly increased in treatment 3 (diet containing 2% VAC) compared to the control and 1% VAC groups (P <0.01). While, addition of 1% VAC fruit powder to diet had no significant effect on GnRH gene expression (P> 0.05). Furthermore, addition of 1 or 2 % VOC fruit powder had no significant effect on LH gene expression (P> 0.05). The results of this study showed that the addition of VOC fruit powder fruit powder up to 2% level could not affect the pituitary-hypothalamic axis of laying hens at 72 to 80 weeks old.

This study aimed to investigate the  effect  of  the method of estimating the effects of markers , QTLs distribution, number of QTLs, effective population size and trait heritability on the accuracy of genomic predictions. Two effective population sizes, 100 and 500 individuals, were simulated by QMSim software. A 100 cM genome including one chromosome was simulated where 500 SNPs and two different  numbers of QTLs (50 and 200) were distributed on it randomly. In this study three levels of heritability (0.1, 0.3 and 0.5) were considered. Genomic breeding values were predicted using Bayesian ridge regression, BayesA, BayesB, BayesC, Bayesian LASSO, Reproducing kernel Hilbert space and neural networks. In this research, the accuracy of genomic breeding values were affected by trait heritability, effective population size, markers effect estimation methods, QTLs distribution and number of QTLs. The Bayes A and B had the highest accuracy while accuracy of neural networks method was the lowest. The accuracy of genomic breeding values were increased as the heritability of trait and number of QTLs increased while the accuracy was decreased as the effective population decreased. Considering the QTLs distribution, the highest accuracy was achieved when the QTLs distributed normally.

Imputation as a method of creating low-density chips to high-density chips has been introduced to increase the accuracy of genomic selection in animals. In the current study, to investing imputation accuracy, three populations of mixed (scenario 1), pure (scenario 2) and mixed + pure (scenario 3) were simulated using QMSim. Two methods of imputation including Beagle and Flmpute were used for two types of low and high density chips. Selected reference population sizes for each scenario were 250, 500 and 1000 animals. The results showed that in all considered scenarios, the accuracy of imputation raised by increasing the reference population size from 250 to 500 animals, but decreased by increasing the reference population size from 500 to 1000 animals. The accuracy of imputation using Flmpute method was greater than that of Beagle for the small reference population (250 animals). In all scenarios and reference population sizes of 500 and 1000 animals, increased accuracy in Flmpute method was not significant in compared to the Beagle method. The accuracy of the imputation was higher for scenario 1than for scenario 2. Also the increase in the accuracy of the imputation in Scenario 3 was not significant in compared to Scenario 1. Generally, the results of the current study showed that in developing countries where small genotyped animal populations are available, to increase the accuracy of genomic selection, using Flmpute method and mixed population and increasing the relationship between the reference and the target population could be a suitable approach.

The egg quality is one of the most important economic factors for layers that are crucial for hatchability and marketing. Given the low number of egg quality traits records, one of the approaches in estimating phenotypic and genetic parameters is multi trait analysis. The aim of this study was to estimate the phenotypic and genetic parameters of west Azerbaijan native hens egg quality traits by multi-trait analysis. For this purpose, 2000 eggs of 14th and 15th generation of pedigree hens were purchased from west Azerbaijan native fowl breeding station and for measuring egg quality traits were transferred to laboratory. The genetic and phenotypic parameters of egg quality traits were estimated by multi-trait analysis using SAS and WOMBAT softwares. The generation-hatching time and storage duration in refrigerator had significant effect on egg quality traits. The mean of some egg quality traits were: egg weight 55.306 g±3.94, egg shape index 75.192±2.9, egg shell percentage 9.389 %±0.73, albumin percentage 60.160 %±2.49, yolk percentage 30.466%±2.35, yolk index 35.928±3.13 and yolk pH 6.442±0.13. The highest and the lowest coefficient of variance were calculated in air cell height and albumin pH, as 16.947 % and 1.366 %, respectively. The highest positive phenotypic correlation was observed between egg weight and egg volume (0.644), and the lowest one was observed between pH of albumen and yolk weight (0.004). The highest positive genetic correlation was observed between egg weight and egg shell surface area (0.999), the highest negative genetic correlation was observed between albumen percentage and yolk to albumen ratio (-0.994). The lowest positive genetic correlation was estimated between yolk index and yolk weight (0.002) and the lowest negative genetic correlation was evaluated between yolk index and dry matter of yolk (-0.005). The range of estimated heritability of studied egg quality traits were 0.212 (albumen percentage) and 0.015 (pH of albumen). Generally, the results indicated that the egg quality traits of Azarbaijan indigenous hens have relatively high phenotypic and genetic correlation, which in order to decreasing the cost of data recording, the number of recorded traits could be decreased. The heritabilities of egg quality traits were moderate to low that indicated the low progress with direct selection.

The Kiss1 gene is one of the known affective gene in fertility, which affects ovulation and multiplication. In this study, Blood samples were collected from 100 sheep of Sanjabi in Mehregan breeding station in Kermanshah province and 50 sheep Ghezel breeding station of Urmia University. After DNA extraction, the polymerase chain reaction (PCR) was used for specific primers amplification of 331 bp fragment of Exon1 Kiss1 gene. Then single strand conformation polymorphism (SSCP) of PCR products was performed and genotypic patterns were obtained using acrylamid gel and the gel stain was obtained by silver nitrate method. The results showed different patterns that could be due to the presence of polymorphism in this position. Three different genotype patterns in samples 1, 2, 3, 4 and 5 for Sanjabi breed  46% ,23% ,3%, 17% and 11% respectively and two different genotype pattern The frequency were 1and 2 for Ghezel breed 0.24% and 0.76%. The association of observed patterns on the multiplicity trait was significant in Sanjabi breed (P <0.05). But this relationship was not in was significant in Ghezel breeds. The results of this study showed that the variation in exon one of the Kiss1 gene can be considered in marker assistance selection programs in sanjabi sheep breed.

In structural equation modeling, it is possible to create hidden variables that cannot be directly measured by the researcher. The aim of this study was to model the structural equations of hidden genetic constructs of production, reproduction and longevity of Holstein dairy cows in Iran using breeding value of the traits that make up these constructs. Accordingly, the breeding value of the traits of the age at first calving, calving interval and the open days made up the hidden genetic construct of reproductive production; the adjusted milk, fat, and protein production traits formed the hidden genetic construct of the product and the lifetime traits in the herd and the productive lifespan constituted the hidden genetic construct of longevity. Estimation of single-trait and multi-trait animal model of genetic variance components, breeding values of each of the above traits was performed using Bayesian method conducted in GIBBS3F90 software. For this purpose, 500,000 rounds were performed and 50,000 initial samples – as burnt-in were removed from analysis. Then, using the variance-based method implemented in SMARTPLS software, 4 conceptual models of structural equation modeling (SEM) were created using the breeding value of the mentioned traits. Using the single animal model, the heritability of milk, fat and protein productions, age at first calving, calving interval, open days, lifetime in herd and production lifespan were 0.36, 0.55, 0.56, and 0.0250, 0.24, 0.07, 0.07 and 0.011, and using the multi-animal model, these values were 0.21, 0.52, 0.42, 0.48, 0.38, and 08, 0.0, 0.74 and 0.51, respectively. The estimated genetic correlation between the traits varied from -0.87 (milk production-fat production) to 0.98 (lifetime in herd and productive lifespan). The report root means square residuals (RMSR) on different SEM models fitted to breeding values of the traits that made up the various structures showed that the best fit was obtained when reproduction and production constructs had causative effect on longevity construct. This type of modeling approach has been used for the first time in the animal sciences which is rooted in social science researches. Therefore, adapting SEM modeling assumptions to the reality of animal sciences data can be a new field for breeding specialists, especially managers of production farms, because researchers in breeding sciences can ask many questions and hypotheses in the form of different constructs and create appropriate and establish a better management for the breeding farm due to the significant causal relationship between the extracted constructs.