مجله تولیدات دامی
سال بیست و چهارم شماره 2 (تابستان 1401)

The aim of the present study was to evaluate the genetic architecture, genomic regions and candidate genes associated with body weight gain, feed intake and feed conversion ratio in Japanese quails. For detection the informative genomic windows, genotyping data on 920 quails was used in a single-step genome-wide association study. The BLUPf90 family software was used to perform related analyses. Theresults was calculated based on the proportion of additive genetic variance (agv) explained by genomic region with an average size of 1.5-Mb of adjacent SNPs. Windows with accounting for more than 1% of the agv were used to identify genomic regions and to search for candidate genes. A total of 13 significant windows over 8 chromosomes were explained 23% of the agv for the body weight gain and including SMYD1, ADGRG6 and CFL2 candidate genes. A peak on CJA2 explained the largest proportion of variance. For feed intake, we identified 20 informative windows across 8 chromosomes and including ACSL, PPA2, FGF2 and RBL2 candidate genes. These regions explained 38% of the agv and a peak on CJA4 explained of agv. Also, for the feed conversion ratio, 12 significant windows were identified on 7 chromosomes and explained 23.7% of agv, contained ATRNL1 and PTPN4 candidate genes. Four genomic regions had a pleiotropic effect. Considering the identification of new genome regions and the key role of the mentioned genes related to feed intake, the single step method can be validated for GWAS in feed efficiency traits.

The aim of this study was to investigate the genetic diversity of different camel breeds in Sistan and Baluchestan province using microsatellite markers. For this purpose, 70 camels were randomly selected from Jamazeh and Baluchi breeds. Jugular vein blood sampling was performed in the tubes containing 0.5% EDTA. The extraction of DNA was performed by salt-detergent method. Five microsatellite markers were selected from the camel genome project with specific primers and banding patterns on 5% agarose gel. Genetic and population structures were analyzed using POPGENE v1.31 software. The number of alleles in five marker positions in Jamazeh and Baluchi breeds ranged from one to six alleles. The number of alleles in five markers CVRLO6, VOLP32, LCV66, WYLLO and CMS17 in Jamazeh are equal to three, two, three, four and one alleles, respectively, and in Baluchi breed with two, four, two, five and one alleles, respectively. According to the results, the range of heterozygosity observed in the studied sites in Jamazeh and Baluchi breeds was in the range from 0.29 to 0.52. The results of FST analysis showed that the two populations were more than 96% similar and the difference between them was 3%. The results of the presentresearchindicated a low rate of polymorphism in the studied sites and in order to preserve breeds and be more adaptable to environmental conditions, it needs more attention and control of inbreeding.

Different types of imported and domesticatedhybrids of silkworm are rearing in different climatic conditions in Iran. The purpose of this study was to compare the performance of silkworm hybrids used in two climatic regions ofIran, namely Shaft in Guilan province and Torbat Heydariyeh in Khorasan Razavi province.For this study, four Iranian hybrids and 14 Chinese imported hybrids were used in a completely randomized block design. For the studied traitsnumber of cocoons per liter, average weight of a cocoon, and weight of cocoon produced from a box, there was a significant difference(P<0.01) between the hybrids as well as the regions. The results of the present study showed that the performance of silkworm hybrids, regardless of their origin, is more affected by the rearing environment and there is a difference between hybrids in the studied climates. Therefore, selecting the most suitable hybrids for different climates of Iran seem to be essential.

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

Effect of organic selenium and chromium supplementation on growth performance, carcass characteristics, and meat quality of broiler chickens was studied using 200 one-day-old Ross 308 male broiler chickens in a 2×2 factorial arrangements with 4 treatments, 5 replicates and 10 birds each. Experimental treatments were including 2 levels of Se-Met (0 and 0.4 mg/kg diet) and 2 levels of Cr-Met (0 and 0.4 mg/kg diet). At the end of trial, two birds per replicates were randomly selected and slaughtered to determine carcass traits and meat quality. Cr-Met supplementation increased feed intake during the grower and the whole period (P<0.05). The birds receiving 0.4 mg/kg of Se-Met and Cr-Met diets had the highest body weight gain (BWG) and the lowest feed conversion ratio (FCR) in the grower, finisher and whole periods (P<0.05). The highest BWG and the lowest FCR in whole period belonged to the birds fed by both elements (P<0.05). The highest relative weight of carcass and breast was observed in birds fed with Se-Met and Cr-Met (P<0.05). The highest relative weight of carcass was seen in birds fed both elements (P<0.05). Addition of Se-Met and Cr-Met increased the moisture and water holding capacity and decreased the cooking loss and malondialdehyde (MDA) content of breast meat (P<0.05). The interaction effect of treatments on meat quality was significant, as the highest water holding capacity and the lowest cooking loss and MDA was seen in broilers fed by both Cr-Met and Se-Met (P<0.05). According to the results of this experiment, it is suggested to add Se-Met and Cr-Met to diet to improve growth performance, carcass traits, meat quality and stability of broiler chickens.

This study was conducted to evaluate the effects of adding different levels of a domestically produced synbiotic to drinking water on production traits, carcass characteristics and the small intestinal microbial population of broiler chickens. Four hundred one-day-old Ross 308 broilers (a mixture of two sexes with equal proportion) were used in a completely randomized design with 4 treatments, 5 replicates, and of 20 birds per each replicate. Experimental treatments included adding levels: zero (control), 50, 100 and 150 g of synbiotic (Biopoul) per 1000 liters of drinking water. At 42 days of age, the addition of 50 or 100 g of synbiotic per 1000 liters of drinking water significantly decreased feed conversion ratio (P < 0.05). The increase of production index in the group receiving 100 g of Biopoul compared to the control showed a tendency (P = 0.08). Biopoul in the levels of 50, 100 and 150 g increased the total number of lactobacilli and decreased the number of yeasts and molds, coliforms and total gram-negative bacteria in the ileum compared to the control (P<0.05). According to the obtained results, the use of 100 g of synbiotic Biopoul per 1000 liters of drinking water of broiler chickens can improve the production index while helping to balance the small intestinal microbial population.

The present experiment was performed to evaluate the effects of thyme (Thymus vulgaris) extract and vitamin E on performance, biochemical parameters of blood and immune system of broilers. Two hundred and forty one-day-old male broiler chicks Ross 308 were used in a completely randomized design with 4 treatments and 4 replications, each replication containing 15 chickens. Experimental diets include 1- control (basal diet without thyme and vitamin E), 2- basal diet+ 250 mg/kg thyme extract, 3- basal diet+ 100 mg/kg vitamin E and 4- basal diet+ 250 mg/kg thyme extract+ 100 mg/kg vitamin E. The results showed that the increase in body weight and feed conversion ratio throughout the period in the diet containing a mixture of thyme extract and vitamin E were significantly increased and decreased, respectively (P<0.05). Differences in cholesterol and LDL concentrations in treatments containing thyme extract and vitamin E, as well as their mixtures, were significantly reduced with control (P<0.05). Thymus weight increased significantly compared to the control in all experimental treatments (P<0.05). In general, the results showed that the use of a mixture of thyme extract and vitamin E in the diet of broilers can improve performance and strengthen the immune system.

Effect of using eucalyptus (Eucalyptus SPP) leaf chloroform oral extract (EE) and black pepper (Piper nigrum) powder (BP) in diet on growth performance, carcass traits, blood parameters and microbial populations of intestine and syrinx was investigated in a 42 days trial with 160 Cobb 500 day-old chicks divided into four treatments and four replicates as a completely randomized design. The treatments were 1- basal diet (control), 2- basal diet and adding 0.1 % EE solution in drinking water, 3- diet having 0.2% BP, and 4- diet having 0.2% BP and 0.1% EE solution in drinking water. Over the study, feed intake of chickens consumed oral EE or BP in diet and/or the combination of them was lower than chickens in control group (P<0.05). Weight gain and feed conversion ratio of chickens were not affected by the treatments. Oral EE resulted in greater percentile lungs weight and lower heart and abdominal fat weights in chickens (P<0.05). Using oral EE or BP in diet and/or the combination of them caused a significant decrease in serum concentrations of glucose, cholesterol and uric acid in chickens (P<0.05). Hematological parameters of chickens were not affected by the experimental treatments. Chickens consumed oral EE or BP in diet and/or the combination of them showed a significant lower intestinal E-coli population than control birds (P<0.05). Furthermore, using oral EE caused a decrease in Mycoplasma population of broilers Syrinx (P<0.05). The results showed that using oral EE leads to lowered abdominal fat and microbial populations of intestine and syrinx while adding BP in diet leads a decrease in microbial populations of intestine in broiler chickens.

The effect of dried corn steep liquor (DCSL) and probiotics on growth performance, intestinal microbial population and humoral immune response of broilers using 320 one-day-old Ross 308 broilers in a 2 × 4 factorial arrangement experiment with four DCSL levels (zero, two, four and six percent) and two levels of probiotic LactoFeed® (zero and 150 mg/kg) were evaluated in a completely randomized design with eight treatments, four replicates and 10 birds per replication for 42 days. Body weight gain, feed intake, feed conversion ratio, lactic acid and coliform bacterial populations, as well as the response of broiler chickens' humoral immune system against Newcastle disease, bronchitis and influenza viruses were measured. In the grower, finisher and whole period effect of LactoFeed probiotics and DCSL and their interaction on body weight gain and feed conversion ratio were not significantly different. In the starter period, birds fed diets containing four percent DCSL consumed more feed and gained more weight than chickens fed diet without DCSL (P<0.05). Interaction of six percent DCSL and probiotic increased feed intake in the starter period compared to diet lacking these compounds (P<0.05). The greatest antibody titer against Newcastle disease, influenza and bronchitis viruses was observed at six percent of DCSL (P<0.05). The interaction of DCSL and probiotics decreased the population of coliforms and increased the population of lactic acid bacteria (P<0.05). According to the results of this study, the use of DCSL and probiotics in the diet of broilers improves the humoral immune response and intestinal microbial population.

The occurrence and spread of inflammation can affect the quantity and quality of eggs in laying hens. Therefore, the aim of this study was to evaluate the effect of soy Gensitein (GEN)on systemic inflammatory status and performances of laying hens post-peak. The research was performed in a completely randomized design, during a period of about 8 weeks, using 80 laying hens of High Line W-36 strains (older than 43 weeks). Experimental treatments were control group (basal diet) and genistein group (basal diet+ 20mg GEN/kg of diet). At the end of experiment, five hens from each treatment were laughter and 50 g of liver sample were taken for gene expression of IL-1, IL-2, TNF-α, COX-1 and COX-2. Results showed that soy GEN decreased gene expression of IL-1 (245 fold), IL-2 (3.53 fold), IL-6 (2.68 fold), TNF-α (4.83 fold), COX-1 (3.92 fold) and COX-2 (1.73 fold) compared to the control group. Laying hens fed GEN diets had higher feed intake and better conversion ratio and had higher egg production rates than the control group.The results of this study showed that soy GEN could reduce inflammation in the liver of laying hens post-peak and improve production performances.

To investigate  the effect of rosemary powder on semen parameters and DNA fragmentation under heat stress, 40 native rooster aged 42 weeksand weighted of 2300 gramswere usedin a factorial experiment in randomized complete block design with two levels of temperature (normal and heat stress) and rosemary powder (0 and 7.5 gr/kg of diet) during 7 weeks. Heat stress and normal temperature was set 28±2ºC and 18-22º C,respectively.After two weeks adaptation,the semen sampleswere collected twice in a week from roosters during 5 weeks using dorso-abdominal massage method. The semen parameters including motility, viability ratio and DNA fragmentation were evaluated. The results showed that heat stress significantly reduced the progressive motility of sperm (type A) and with the addition of rosemary powder, sperm viability increased (P˂0.05). Addition of rosemary leaf powder at normal temperature decreased the DNA fragmentation ratio (P˂0.05). In roosters under heat stress,the DNA fragmentation rate of sperm increased and the damage rate decreased significantly with the feeding of rosemary powder (P˂0.01).  According to the results of this study, adding rosemary powder to the diet of native old roosters under heat stress conditions can improve some reproductive traits