فصلنامه پژوهشهای تولیدات دامی
پیاپی 14 (پاییز و زمستان 1395)

The aim of this research was to estimate the variance components and genetic parameters for silkworm cocoon traits using univariate and multivariate models, and comparison of average productivity and resistance traits among three different selection strategies in two commercial silkworm lines of 153 and 154. Genetic parameters of cocoon weight, cocoon shell weight and cocoon shell percentage were estimated after three generations of selection, using the REML algorithm of the WOMBAT software. Selection criteria were conventional three-trait index (A) and basal three-traits index (B) based on cocoon weight, cocoon shell weight and cocoon shell percentage. For these goals, data were collected for two commercial silkworm pure lines of 153 and 154 during 2006-2010 in the Iran Silkworm Research Center (ISRC). In general, the obtained results of mean comparisons showed that strategy A can be recommended for improving of all productive traits. Total genetic gain obtained from three generations of selection for all traits in strategy A in pure line 153 was higher than line 154. Regarding to the high values of heritability for studied traits in univariate and multivariate analyses, it can be concluded that additive genetic effects had more effect on the phenotypic values of these traits and consequently the improvement of these traits in breeding programs would be possible.

The objective of this experiment was to evaluate the effect of feeding different levels of garlic and cinnamon powder on antioxidant system and some blood parameters of broilers under heat stress condition. Two hundred forty commercial broiler chicks (ROSS 308) were dividing to 6 treatments and 4 replicates. This experiment was performed in a completely randomized design with 2*3 factorial trials, which included 2 levels of garlic powder (0, 1.5% ) and 3 levels of cinnamon powder (0, 0.4 and 0.8 %). The chicks were exposed to heat stress (32 oC) from day 29 to 42 for 6 hours. In d 40 and 42, two chicks from each replicate was chosen for collecting blood. Garlic and cinnamon powder did not effect on performance parameters. The results showed that different levels of cinnamon did not affect on serum MDA concentration, while garlic powder were significantly reduced MDA concentration (P

This experiment was conducted to evaluate the effects of ajowan (Carum Copticum) and coriander (Coriandrum sativum) seeds on growth Performance and carcass characteristics. A total of 288 one-day old chickens (Ross 308) were used as factorial experiment (3×3) in a completely randomized design in 9 treatments including ajowan levels (0, 1% and 2%) and coriander levels (0, 1% and 2%) with 4 replications and 10 birds each for 6 weeks age. Results were showed treatments containing 1% levels of ajowan and coriander seeds showed significantly better weight gain and performance compared to other treatments (P

In this research, influence of Revabio enzyme on improving anti-nutritional of wheat bran (high in fiber, non-starch polysaccharides and phytate) were investigated. The total number of 320 commercial male broiler chicks (Ross 308) in a factorial experiment 4×2 with four replications were used. Treatment consists of four levels of wheat bran (0, 10, 15 and 20 percent) and two levels of enzyme (0 and 0.05 percent), respectively. The experiment was carried on 42 days and divided into 3 period of starter, grower and finisher. Feed intake, body weight gain and feed conversion ratio (FCR) were determined for each week of experiment. In day 42, 2 birds from each unit were slaughtered and blood sampling was taken. The results showed that including wheat bran in the diets had no significant effect on weight gain and feed conversion ratio in total period. With increasing wheat bran levels, the average of weight gain was decreased. Adding enzyme to diets significantly improved weight gain and feed conversion ratio. The use of wheat bran in the diet reduced blood glucose and incresed zinc consentration significantly (P

Considering the role of arginine in the prevention of ascites and the possibility of replacing this amino acid with Guanidinoacetic acid (GAA), in present study, the effects of different levels of GAA (0.5 and 1 g/kg diet) supplementation in low-protein diets on growth performance and ascites incidence in broiler chickens were investigated. Therefore, a total of 208 male broilers (Ross 308) were used in completely randomize design with four treatment with four replicate in each treatment. The chicks were reared on the floor up to 42 day. Treatments consisted of a normal-protein diet (NPD) according to the National Research Council (1994) and a reduced-protein diet (RPD) with reduced 30 g/kg of crude protein relative to the NPD. Two reduced-protein diets with similar RPD that supplementing with 0.5 and 1 g/kg GAA were also prepared. Results show that levels of protein and GAA supplementation had no significant effect on growth performance and breast and thigh percentage. The relative weight of liver, heart, and right ventricular weight ratio (RV: TV) significantly (P

In order to investigate the effects of microwave irradiation of barley or enzyme supplementation of barley based diets, 12-day-old broiler chicks (n=320) from Ross 308 strain were arranged in a 2×2 factorial experiment consisting of 2 duration times of microwaves irradiation of barley (0 and 220 second) and 2 levels of dietary Rovabio multienzyme level (0 and 1 g.kg-1) with 4 replicates per treatment and 20 birds in each replicate. Four treatments were included: 1) basal diet with non-irradiated barley, 2) basal diet with non-irradiated barley multienzyme, 3) basal diet with microwave irradiated barley and 4) basal diet with microwave irradiated barley multienzyme. Irradiation of barley was carried out by a microwave oven (Model 245, Butan Co, Iran) at 880 W and 220 S. Feed intake (FI), weight gain (WG) and feed conversion ratio (FCR) were recorded weekly. At the end of experiment 8 birds per each treatment were selected and blood sampling was done. To measure carcass characteristics, 2 birds per each pen were weighed and slaughtered at 42 days of age. Results indicated that irradiated barley had no effect on broilers FI. However, the overall WG and FCR and gizzard relative weight increased. Use of Irradiated barley resulted in increases in the concentration of serum total cholesterol, HDL-C and LDL-C. Broilers fed diets containing β-glucanase enzyme had 4% improvement in overall FCR. Use of enzyme resulted in increase in abdominal fat, gizzard weight and serum HDL-C and also resulted in a decrease in thigh weight. Serum ALP and TP in the broiler chicks were not affected by barley irradiation, enzyme supplementation and their interaction. There was a significant linear regression relationship between weight gain in the whole experimental period and serum HDL-cholesterol concentration (at day 42) in broiler chicks. It was found a significant linear regression relationship between serum total cholesterol and HDL-cholesterol concentrations in the 42 d-old broiler chicks. It is concluded that β-glucanase enzyme and dietary barley irradiation had some useful effects on broiler's performance. Due to independency of the effects of these two processing methods on performance and blood characteristics, simultaneous use of them has not any problems.

Ascites is a metabolic disorder that accounts for over 25% of overall mortality in the broiler industry. The objective of this study was to determine the effects of ascites induction on the clinical pictures, mortalities, growth performance, carcass yield and internal organs characteristics of two different Lines of broilers. One hundred Line broiler chicks were selected from two Lines (Line A & B) that differed in feed conversion ratio and growth rate. These included an high growth rate-low feed convertion ratio (Line A), an ascites-resistant line (Line B). To increase the incidence of ascites, chicks of two group were fed ad libitum with a higher condensed diet and reared under a lower ambient temperature. Ascites incidence was clearly higher in Line A chickens. The mean values of carbon dioxide tension of line A chickens were significantly higher than line B chickens at 12 days of age. weights of liver and breast muscles and length of jejunum and ileum of line A were significantly greater than Line A chickens.

The experiment was conducted to evaluate the effect of antibiotic, organic acid, probiotic and prebiotic on performance and small intestinal morphology in male Ross 308 broiler chicks for 42 days in tropical conditions. The study was completely randomized design with 5 treatments, 4 replicates and 8 chicks per each. The treatments were: T1: basal diet, T2: diet containing antibiotic oxytetracycline (150 g/ton of feed), T3: diet containing organic acid orgacid (3 kg/ton of feed), T4: diet containing probiotic protoxin (150 g/ton of feed) and T5: diet containing prebiotic mannan oligosaccharide (2 kg/ton of feed). The results showed that the experimental diets had no significant effect on feed consumption, live weight and feed conversion ratio. The relative length of jejunum and ileum by prebiotic significantly increased (P

The objective of this study was to investigate effect of conjugated linoleic acid (CLA) on egg production and hatchability in broiler breeders. This experiment was conducted in a completely randomize design with three levels of conjugated linoleic acid (0, 0.25 and 0.5 percent of diet) and four replicates. Each experimental unit consist ten broiler breeders (ROSS 308). The experiment was taken at 50 week and continues to four weeks. During the experiment, egg production, egg weight, egg mass, hatchability and embryonic mortality were recorded weekly, whereas yolk height, yolk diameter, shell thickness, shell weight and shape index were assayed in the entire of experiment. Results showed that supplementation of 0.5 percent CLA to diet, significantly increased egg albumin and yolk height in compare to 0.25 percent. In conclusion, addition of CLA didn’t have significant effect on broiler breeder productive performance and hatchability.

This study was performed by five treatments and three replicates using 180 Ross male broilers (12 birds in each pen) in a completely randomized design. Feed restriction was applied by supplementing the rice hull levels (0, 15, 30, 45 and 60 percent). To grower feed (7 to 14 days of age). Average feed intake had a linear decrease with increasing in rice hull levels. Body weight was decreased linearly in 14, 21 and 28 days of age, but due to compensatory growth there were not any significant differences in body weight on 35 and 42 days. Average of feed conversion ratio decreased by increasing in rice hull levels up to 30 percent but in higher levels feed conversion ratio increased linearly. Feed restriction during 7-14 days of age has any significant differences in carcass percentage and its parts. Concentration of plasma triiodothryronine (T3) and thyroxine (T4) increased in 15% rice hull groups (P0.05). Feed dilution by rice hull up to 15-30 percentages in the second week of broiler production is recommended.

This study was conducted to consider the effect of theophylline in laying and some of egg characteristics on laying hens. Commercial egg type Hy-Line hens were used in a completely randomize design with 4 treatments and 3 replicates for 50 days period. The levels of different theophylline supplements (treatment) were 0 (control), one, three, and five mg per kg of body weight for 50 days. The average data were compared by using Tukey–Kramer multiple comparison tests. All levels of theophylline significantly increased laying performance. The best laying performance was observed in 3 mg/kg of theophylline. The best effect on egg size, weight, yolk and albumen height was found in hens receiving highest concentration of theophylline (p≤ 0.05). All levels of theophylline significantly decreased yolk color index (p≤ 0.05). The lowest yolk diameter was observed in 3 mg/kg theophylline. The highest albumen Haugh unit was in 1 mg/kg theophylline (p≤ 0.05). Results showed that theophylline increased the rate of laying and some of egg characteristics in hens. The best laying performance was showed in 3 mg/kg and the highest egg weight and size in 5 mg/kg of body weight theophylline.

The objective of this study was to consider effect of three different time of starting Ovsynch after Artificial Insemination, on synchrony parameters, pregnancy loss and fertility in Holstein cows. Multiparous cows (> 30 Kg/d, n = 450) randomly assigned to one of three groups. Groups according to time of starting Ovysnch were as follows: 1- Starting Ovsynch on day 25 after AI, 2- Starting Ovsynch on day 28 after AI and 3- Starting Ovsynch on day 32 after AI. All cows received an injection of GnRH at time of starting Ovsynch regardless of their pregnancy status, and cow’s diagnosed not pregnant using transrectal palpation received an injection of PGF2alpha seven days later and continued the protocol to receive an injection of GnRH 56 h after PGF and TAI 16 h later. Ultrasonography used to determine response to three injection of Ovsynch, pregnancy diagnosis at first check (32±3 after AI) and second check (65±4 after AI). Results showed response to first GnRH of Ovsynch and ovulatory response to second GnRH of Ovsynch affected by time of starting Ovsynch (P = 0.03). Proportion of cows responded to first GnRH of Ovsynch in group started Ovysnch on day 32 after AI (74.0%) was higher compared to groups started Ovsynch on day 25 (46.0%) or 28 (50.0%) after AI (P = 0.03). Ovulatory response to second GnRH of Ovsynch was greater in groups 32 compared to other groups (P = 0.02). Conception rate at day 32 (P = 0.02) and 65 (P = 0.01) after AI was greater in cows started Ovysnch on day 32 after AI (28.0 and 25.3%) compared to groups started Ovsynch on day 25 (20.6 and 19.3%) or 28 (22.0 and 20.0%) after AI. Cows starting the Ovsynch protocol 32 d after previous AI increased fertility by improving synchrony to the protocol.

The present study was conducted to evaluate the effect of L-carnitine supplementation accompanied with two sources of fat supplemented diets (ω3 and ω6) on flushing period of Farahani ewes. 20 Farahani ewes were allocated in four different treatments which were as follow: 1) 2.5% dry matter intake ω3 source without L-carnitine 2) 2.5% dry matter intake ω6 source without L-carnitine 3) 2.5% dry matter intake ω3 source with 500 mg L-carnitine 4) 2.5% dry matter intake ω6 source with 500 mg L-carnitine. The experiment was conducted as completely randomized design and the study was lasted 42 days. Some blood metabolites were studied and fertility parameters were considered as well. The results of the present study showed that blood metabolites concentrations such as glucose, cholesterol, hepatics enzymes (AST, ALT), HDL lipoprotein and insulin were not significantly different among the treatments (P

Two experiments were conducted to evaluate the effect of essence of various species of Thymus on in vitro gas production parameters and digestibility of dry matter and organic matter. Various species of Thymus medicinal plant was collected from different area: Shriaz (Zataria multiflora), Esfarayen (Thymus transcaspicus lamiaceae), Shahrood (Thymus fallax), Golestan forestry (Thymus transcauasicus) and Gorgan (Thymus vulgaris). Essence of collected samples was taken by macro wave at 110 0C and 450 nm for 45 minutes. Treatments were including: 1) control containing basal diet with forage: concentrate ratio 50:50 (without essence) and treatment 2 till 6 containing basal diet and essence of various species. Results showed that adding essences from various species had significant effects on potential gas production and gas production rate (p

The objective of this study was to investigate the effects of feeding sources of carbohydrates with different fermentation rate on reproduction performance of Moghani grazing ewes. Sixty Moghani ewes were allocated randomly to four nutritional groups as follows 1) without supplement feeding (control), 2) feeding 300 g barley grain per day, 3) feeding 300 g corn grain per day and 4) feeding 300 g concentrate mix containing ground barley grain and starch powder with 1 to 1 ratio from d 7 to d 14 of synchronization program. Estrus synchronization was done using CIDR for 14 days. At CIDR removal, the ewes in each group were received 400 IU PMSG intramuscularly and after 24 h, they were inseminated with frozen Romanov semen. There were no significant differences between experimental treatments for fecundity, prolificacy and twinning rate. Feeding carbohydrate sources increased blood glucose concentration (P=0.0567) and decreased urea concentration (P=0.0073) after 7 days feeding in compare to the control group. However, there were not significant differences between carbohydrate sources. The results of present study showed that feeding different carbohydrate sources as short term nutrition during estrus synchronization could have positive effects on energy metabolism of animals.

Effect of drying method was investigated on chemical composition, nutrient digestibility and rumen fermentation parameters of alfalfa hay harvested in the morning or afternoon. Experimental treatments consisted of alfalfa harvested in the morning and dried in sun, alfalfa harvested in the afternoon and dried in sun, alfalfa harvested in the morning and dried in shadow, alfalfa harvested in the afternoon and dried in shadow, alfalfa harvested in the morning and dried in oven, alfalfa harvested in the afternoon and dried in oven, alfalfa harvested in the morning and dried in microwave and alfalfa harvested in the afternoon and dried in microwave. In vitro digestibility and ruminal fermentation parameters were determined by two steps and gas production methods. The highest acid detergent fibre and lowest dry matter content were observed in alfalfa dried in oven and shadow, respectively (P

In order to investigate effect of cutting on chemical composition and degradability parameters of sorghum silage an experiment was don. Sorghum forage was used from first and second cutting for ensiling. Ensiling was done in plastic buckets (2.5 kg weight) for 80 days. The result showed that dry matter, neutral and acid detergent fiber in silage of second cutting was higher (P

The investigation was carried out to determine of chemical composition and dry matter, neutral detergent fiber (NDF) and crude protein (CP) degradability parameters of Kahoorak (Prosopis stephaniana) by using nylon bag technique. Plant samples were taken from the Sar Chah Amari of Khoosf in Birjand city. Samples were collected at three stages of plant growth (vegetative, fruiting and seeding stages) and fruit at two stages of growth (Fruiting and seeding). Four fistulated Brown Swiss heifers were used for determination of dry matter, CP and NDF degradability after incubation for 0, 2, 4, 8, 16, 24, 48 and 72 hours. Maximum CP of Prosopis stephaniana was in branches (13.24%) and plant fruit (10.88%) in vegetative stage. With advancing in plant growth CP and tannin content was reduced but NDF and ADF content was increased. Degradation fractions (a and b) of CP in fruiting stage was more than seeding stage (p

The most important traits of animal are affected by quantitative trait loci and environmental effects. Peroxisome proliferator’s active receptor gamma co activator 1 alpha (PPARGC1A) gene is a member of transcription co activators family, which plays a central role in cellular energy hemostasis regulating. In this study, blood samples were collected from hundred Brown Swiss cow and DNA was extracted from whole blood by modified salting out procedure. Two SNP positions, one located in the 3́-untranslated region (A/C) and the other one in iron 9 of PPARGC1A-T19C were genotyped by PCR-RFLP. Breeding values were individually predicted for milk production, fat and protein milk percent traits by DFREML model one. Association between polymorphisms and breeding values were investigated by SAS at 5% significant level. Genotype frequencies of AA, AC and CC genotypes at PPARGC1a-A968C were 0.593, 0.385 and 0.022, as well as, the allele frequencies of A and C were 0.786 and 0.214, respectively. Genotype frequencies of TT, TC and CC for PPARGC1a-T19C were 0.165, 0.428 and 0.407 and the allele frequencies of T and C were 0.379 and 0.621, respectively. Chi-square test of the both SNPs indicated Hardy-Weinberg expectations (P

The aim of present study was to estimate genetic and phenotypic trends for body weight traits at some ages in Lori-Bakhtiari lambs. In this study a total of 7721 records on birth weight, 6462 records of one month weight, 7275 records of weaning weight 5745 records of 6 month weight, 3326 records of 9 month weight and 3088 records of 12 month weight of Lori-Bakhtiari sheep was used to reveal the genetic and phenotypic trend of growth traits. The data was collected in Shahrekord sheep breeding station during 1989-2010. The SAS statistical software was used to evaluate the effect of environmental factors. Wombat software was employed to estimate genetic parameters and animals breeding value. Environmental factors, like birth year, sex, birth type and the age of mother were significant factors as fixed effects (P

Reproductive records of 5327 Zandi ewes were collected from a research flock at the Zandi sheep breeding from Varamin station during 1991-2011. Genetic parameters were estimated for main traits such as conception rate (CR), number of lambs born (NLB), number of lambs at weaning (NLW) and the composite traits including number of lambs born per ewe exposed, number of lambs weaned per ewe exposed, total litter weight at birth, total litter weight at weaning, total litter weight at birth per ewe exposed and total litter weight at weaning per ewe exposed. Year, age of ewe, breed of ewe on breeding were used as fixed effects. Direct and maternal genetic effects, permanent environmental effects of ewe and mate of ewe were considered as random effects in the model. The effect of environmental factors such as mating year and age of ewe at mating on all of reproductive traits were significant (P >0.01) exception CR, NLB¡NLB/EE, NLW NLW/EE, TLWB. Parametric and variance components were estimated by linear and threshold models. Estimates of heritability for animal genetic effects were mainly small and ranged from 0.0011 to 0.1 in linear model while the estimates resulting from thershold were ranged from 0.009 to 0.063. Estimates of heritability's for animal genetic and permanent environmental effects were low mainly due to the typical strong influence of environmental factors on reproductive traits. Estimates of repeatability's for animal permanent environmental effects were low to medium by linear analysis, and medium by threshold analysis.

To investigate the effects of categorical trait levels on EBVs accuracies, genetic and phenotypic trends and inbreeding coefficient, a breeding stock contained 400 animals was simulated through stochastic method using R programming package. The population was simulated for 7 generations while each generation contained 200 animals. The generations were overlapped and in each ones 20 percent of the best males and all of the females had a chance to participate in the mating program up to 5 generations. A categorical trait with heritability of 0.25, mean of 5 and standard deviation of 2 was simulated, and on the basis of recording approach, 4 scenarios were designed. In the first scenario a threshold trait was measured as continuous records, while for scenarios 2 to 4, regarding to the appraiser ability a threshold trait were recorded in 3, 5 and 9 categories respectively. Breeding values were estimated by a simple, single trait animal model and all scenarios were replicated for 10 times. The accuracy of breeding value estimations for scenarios 1 to 4 were 0.62, 0.49, 0.59 and 0.61 respectively (p0.05). Results showed that, the improvement of recording accuracies for threshold traits lead to increasing in the accuracy of breeding value estimations and the genetic gain. So this is concluded that the development of more accurate measurement tools for threshold traits, could improve the genetic gain and breeding program efficiency.

Native chickens are considered as national genetic resources and their conservation is very important from biodiversity aspects. The study of mitochondrial genome in one breed and comparing it with others can be a useful index for genetic diversity in that population. This study carried out for determining the sequences of mitochondrial high variable 1 (HVR-I) of D-loop region in Fars native chicken. Blood samples were collected randomly from 20 birds. After extracting DNA from whole blood, the HVR-I region was amplified using specific primers and then was sequenced. Totally, 12 sequences were obtained properly. After analyzing of the sequences, three haplotypes were identified with 5 single nucleotide polymorphic sites (SNP). These changes were mainly observed from nucleotides 217 to 446. After obtaining similar mtDNA sequence from GenBank, phylogenetic tree was drawn. Phylogenetic results indicated the Fars native chickens were clustered with Azerbaijan native, White Leghorn, Silky, Sonneratii, Barred Plymouth Rock, Iranian Marandi and Mazandarani native chickens. Therefore, we conclude that the Fars chicken might has some genetic similarities with these chicken breeds.

This study was carried out to identify polymorphisms of BMP15, GDF9 and BMPRIB genes in cross- bred of Romanov×shal sheep. For this reason 79 blood samples were collected from a flock in Gonbad kavous city in Golestan province. DNA was extracted using modified salting out method. Polymerase chain reaction was done by specific primers for amplification of two fragments with 141and 153 bp from exon 2 of BMP15, one fragment with 190 bp from BMPR-IB gene and two fragment with 462 bp, 139bp from exon 1and 2 of GDF9 genes, respectively. The results obtained from digested PCR products did not confirm the existence of mutation in BMp15, BMPR-1B and in exon 2 of GDF9 marker site. While, polymorphism was observed in exon 1 of GDF9 marker site and the heterozygotes were estimated as 0.11 in this population.

In this research, estimation of genetic parameters for milk production trait was performed by using collected data from 1991 to 2010 in Iranian Holstein dairy cattle. Genetic parameters were estimated by MATVEC Microsoft, using animal model, with univariate and multivariate analysis. The data set were including 161328, 123369 and 81013 records for first, second and third lactations, respectively. Based on univariate analysis, heritability estimates for three lactations were 0.25, 0.20 and 0.15, respectively. Multivariate analysis was performed twice for each lactation and variances and heritability estimates were averaged. Heritability estimates of milk yield were 0.25, 0.21 and 0.15 in first, second and third lactation, respectively, with multivariate analysis. Genetic correlation were 0.95, 0.98 and 0.91 between first-second, second-third and first-third lactations and phenotypic correlations between them were 0.65, 0.62 and 0.55, respectively. Results showed that the heritability estimates of milk yield were decreased from the first to the third lactation; also, genetic and phenotypic correlations between consecutive lactations (first-second and second-third) were more than inconsecutive lactations (first-third) lactations.

Genomic selection combines statistical methods with genomic data to predict genetic values for complex traits. The accuracy of prediction of genetic values ​​in selected population has a great effect on the success of this selection method. Accuracy of genomic prediction is highly dependent on the statistical model used to estimate marker effects in reference population. Various factors such as density markers, reference population and genetic architecture affect choosing the best model for analysis. The aim of this study was to evaluate methods for genomic selection in the Iranian Holstein population. Four Bayesian linear regression models, Bayes-A, Bayes-B, Bayes- , Bayesian-LASSO and a genomic linear method (GBLUP) were compared using stochastic simulation across three types of reference population and a range of numbers of quantitative trait loci (QTL) in two classes of marker density. Bayesian methods had a higher accuracy than GBLUP especially when the number of loci was low and data from other population were used. Construction of reference population by bulls and cows together with data from other populations and using Bayes B is suggested for genomic selection in Iranian Holstein.