مجله علوم دامی ایران
سال پنجاه و پنجم شماره 1 (بهار 1403)

In order to investigate the effect of different levels of sulfur bentonite on performance, digestibility of nutrients, rumination behavior, blood and rumen parameters in Dalagh ewes, 18 non-pregnant lactating ewes with an average weight of 38±3.5 kg were used. This experiment was conducted in a completely randomized design with three treatments and six replications. The treatments included: 1- control (without sulfur bentonite), 2- containing 0.15% dry matter sulfur bentonite and 3- containing 0.3% dry matter sulfur bentonite. The results of this experiment showed that different levels of bentonite sulfur in ewes had no significant effect on the weight at the end of the experiment, daily weight gain, feed conversion ratio, dry matter intake, rumination behavior, cholesterol, triglyceride, total protein, albumin, globulin and blood albumin/globulin ratio. The use of different levels of bentonite sulfur reduced the apparent digestibility of dry matter and organic matter, increased glucose and blood urea (P<0.05). Also, bentonite sulfur treatments had lower protozoan population, pH of three hours after morning feeding and higher rumen ammonia concentration than the control treatment (P<0.05). In overall, the use of sulfur bentonite up to 0.3% of the dry matter of the diet decreased the digestibility of dry and organic matter, although a tendency to improve the feed conversion ratio and daily weight gain was observed

The aim of this study was to investigate the effects of dietry cation-anion difference (DCAD) levels and crossbreeding on carcass characteristics of lambs. In this study, 30 Lori Bakhtiari and  first generation Lori Bakhtiari × Romanov × Pakistani lambs (50% Lori Bakhtiari, 25% Romanov, 25% Pakistani)  with an average age of 90±10 days and an average weight of 33±1.5 kg were divided into two groups of 15 lambs, each group was fed with a different level of DCAD. Carcass weight, carcass yield, viscera weight, cross-sectional area of Longissimus muscle and carcass length did not show any significant difference between purebred and crossbreds and also between diets. Crossbreeding also significantly increased the weight of valuable and salable carcass parts (P<0.05). However, according to our findings, no difference was observed in terms of weight of salable carcass parts between anionic and cationic treatmentsgenotype and DCAD did not have any significant effect on the composition of carcass fatty acids. The meat shear force of Lori Bakhtiari × Romanov × Pakistani lambs compare to Lori Bakhtiari  lambs and anionic diet compare to cationinc diet was lower (P<0.05). Lori Bakhtiari lambs had a higher mean in brightness index and Longissimus muscle redness than Lori Bakhtiari × Romanov × Pakistani lambs (P<0.05). Therefore, anionic diets and Crossbreeding can be considered as effective ways to increase the quality and crispiness of sheep meat.

Paratuberculosis  known as Johne's disease, is a contagious, chronic, intestinal disease in ruminants, which is caused by Mycobacterium avium paratuberculosis subspecies (MAP) and causes a huge economic damage to the livestock industry. There is no effective treatment nor vaccine for MAP infection. Thus, investigating the genetic regions associated with susceptibility to MAP infection can provide a better understanding of paratuberculosis mechanisms and contribute to the genetic improvement of animals. The aim of this study was to identify genomic regions and candidate genes associated with susceptibility to MAP infection in Holstein dairy cattle using a genome-wide association study (GWAS). For this purpose, blood samples of 150 cows were collected, and DNA and serum of them were extracted.The prepared DNA samples were genotyped using bovine SNPchip30k (Illumina). Quality control of genotypes was performed based on the minor allele frequency (PMAF < 0.05), missing genotype (PMIND > 0.05), genotyping rate (PGENO > 0.05), and Hardy-Weinberg equilibrium (PH-W < 1) 10-6) using PLINK software. The association was performed using a mixed linear model in PLINK software. After quality control, 28749 markers on 142 cows (99 cases and 43 controls) were remained for the further analysis. Associations analysis showed that 16 markers located in chromosomes 30 and 6, were associated with  Johne's disease. Positional candidate genes for Johne's disease were identified. The most important identified genes were LMX1A, THSD7A, ELMOD2, ATP6AP2, RNF150, SLIT3, SDE2, PARP1, PBX1, TFB2M, SMYD3 and PYCR2. Gene ontology analysis showed that most of the identified genes are involved in the nervous system, cytoskeleton system, regulation of cytokines, Golgi apparatus, catalytic activity, calcium ion transport, and resistance to diseases. Whole genome-wide association study (GWAS) and ontology analysis (GO) can help to identify candidate genes and regions related to sensitivity to MAP in dairy cows, which can play an important role in the treatment and prevention of Johne's disease.

The aim of this study was to investigate the chemical composition of corn steep liquor precipitated with tannins (CSLP) and its effects on trait performance and health condition of Holstein  calves as a new protein source in milk replacer (MR). A total of 60 Holstein dairy calves (n=20 calves per treatment: 10 males and 10 females) were randomly assigned to the one of the three treatments, including: 1) control group, 2) MR+2% CSLP and 3) MR+4% CSLP. The experimental results showed significant difference on percentage of amino acid profiles in CSLP and MR (except serine, Histidine, Glycine and Tyrosine) (P<0.05). The percentage of crude protein CSLP (26.56%) was significantly higher than MR (22%). The performance traits of calves were not affected by the experimental treatments. Feeding MR+2% CSLP led to a significant reduction of Escherichia coli in fecal on day 28. The use of CSLP had no negative effect on the fecal consistency score of calves from 0 to 56 days of ages (P<0.05). In conclusion, feeding of CSLP as a protein source in MR had no negative effect on trait performance and health of dairy calves

Litter size (LS) is one of the important economic traits in sheep . This trait is influenced by some genes with a large effect. The purpose of this simulation study was to evaluate the fixation selection designs for favorable major gene allele under scenarios of overlapping and discrete generations. In this regard, a trait with heritability of 0.1, and a genome with 26 chromosomes and a major gene was simulated in sheep population. Animals breeding value was predicted using Bayesian threshold model. Selection of animals was based on estimated breeding value (EBV), phenotype (PHEN) and random (RND). After ten generations, genetic gain in selection based on EBV, PHEN and RND under scenario of discrete generation were 8, 23 and 26 percent higher than those in scenario of overlapping generation, respectively. The accuracy of prediction in scenario of discrete generation was higher than scenario of overlapping generation. Means of inbreeding coefficient under scenario of overlapping generation and selection for EBV, PHEN and RND were 0.317, 0.029 and 0.027, respectively, and for scenario of discrete generation were 0.327, 0.058 and 0.056, respectively. In generation ten, the favorable allele of the major gene, in scenario of discrete generation selection based on EBV, PHEN and RND was 1, 46 and 38 percent higher than those in the scenario of overlapping generation, respectively. The results indicated that the scenario of discrete generation selection based on EBV leads to more fixation the favorable allele of the major gene and of genetic gain.

Genetic evaluation of sport horses using various methods is commonly carried out in many countries, except for Iran. Accurate estimation of genetic parameters for functional traits in horses has always been a subject of interest among livestock breeders. The aim of this study was to investigate the genetic parameters of athletic performance traits in Iranian jumping horses. Traits include race completion time (RCT), rank at the end of the competition (REC), and number of errors in the competition (NEC). The study were conducted based on Equestrian Federation of Iran (FEI) athletic performance records of 1498 horses (10–23 years old). The genetic parameters were estimated by using Restricted Maximum Likelihood (REML) procedures and airemf90 software. The statistical model included fixed effects of birth year, sex, age, breed, height of obstacles, date/city, level of difficulty of the event and random effects of rider, permanent environment and an additive genetic effect. Heritability of RCT, REC and NEC traits were estimated 0.03, 0.11 and 0.09 and their repeatability were 0.16, 0.25 and 0.13, respectively. Genetic and phenotypic trends of RCT, REC and NEC traits were estimated -0.002, 0.0091, 0.0003 and -0.7057, 0.2575, -0.0807, respectively. According to this result, the performance traits are highly affected by environmental factors, especially the effect of the rider, but among the studied traits, selection based on rank traits can lead to more genetic progress. It can be concluded that we can apply these parameters to improve the genetic potential of show jumping performance records and design the appropriate breeding strategies for horse jumping population in Iran.

In this study in order to estimate inbreeding coefficient and identify the ROH Islands associated with the genes under selection, the 50k BeadChip genotyped data of 206 sheep from 3 different Egyptian breeds were used. After quality control, 48361 SNPs in 204 sheep were remained for the future analysis. Inbreeding coefficient was calculated using four methods including, genomic relationship matrix (FGRM), excess of homozygosity (FHOM), correlation between uniting gametes (FUNI) using the GCTA 1.0 software and run of homozygosity (FROH) using the PLINK 1.9 software. One percent of SNP with the highest frequency in ROH were considered as ROH Islands. The lowest rate of inbreeding according to (FGRM, FHOM, and FUNI) was related to Wahati and the highest was related to Saidi breed. The highest amount of FROH (0.043) was observed in Saidi and the lowest amount (0.018) was observed in Barki breed. Average length of ROH ranged from 45.02 to 205.87 Mb, while the average number of ROH ranged from 8.14 to 14.07. The highest number ROH was observed on chromosome 2, while the lowest was on chromosome 26. Average inbreeding coefficient from FROH in Barki, Saidi and Wahati were estimated 0.018, 0.043 and 0.027 respectively. A total of 62 ROH Islands with length: 24.60 Kb to 13 Mb were identified, which covering less than 1% of the sheep genome. The ROH Islands was not distributed across the genome uniform and varied among breeds, but some common were identified. Bioinformatics analysis demonstrated that some of these genomic regions overlapped with reported genes that directly or indirectly influenced traits for adaptation and immune system (SEMA3D, CSF2, ITPR1), development of the skeletal muscle (UGGT1, ITGA2), and reproduction (ABHD16B). The results of this study revealed that, the selection processes in different sheep breeds for economic traits during several years, has led to the formation of many ROH islands in sheep genome, therefore scanning these regions at the genome level can be an alternative strategy to identify genes and associated loci with economic traits.

This study aimed to investigate the nutritional effects of phytosomal green tea on growth performance, lipid parameters, immune responses, antioxidant status, ileum bacterial population, and gamma interferon gene expression in compared to green tea extract. 375 male broiler chickens (ROSS 308)were randomly assigned to 5 treatments, with 5 replications and 15 chickens per cage. Treatments included 1- basal diet (negative control), 2- basal diet + 0.10 g/kg avilamycin, 3- basal diet + 0.60 g/kg salinomycin, 4- basal diet + 400 ml/kg green tea extract and 5-basal diet + 300 ml/kg green tea phytosome. Experimental treatments did not affect growth and carcass performance (P>0.05). Malondialdehyde, triglycerides, low density lipoprotein cholesterol in plasma affected by phytosomal extract decreased compared to control (P<0.05). Antibody levels against red blood cells, immunoglobulin G and immunoglobulin M increased in chickens fed phytosome supplement in comparison to the form of green tea extract at 28 days (P<0.05). The use of green tea extract reduced the population of Escherichia coli in comparison to avilamycin and increased the population of lactobacilli cmpared to salinomycin (P<0.05). The expression of interferon gamma gene in the spleen of chickens that received the phytosomal green tea extract was higher compared to the consumption of green tea extract (P<0.05). Conclusion is that, green tea extract -phospholipid complexes showed the same efficiency compared to green tea extract on the evaluated parameters and can be considered as an alternative in order to reduce the consumption of plant extracts in poultry nutrition.

This research was conducted to investigate the effect of different concentrations of Diazinon as a pesticide, that is widely used in agriculture, on the expression of steroidogenic genes and DNA methylation of promoter site of StAR gene in in vitro maturation of goat oocytes. To prepare goat oocytes, ovaries were prepared from a slaughterhouse and transported to the laboratory into the flask containing warm saline (30-34oC). Oocyte-cumulus complexes (COC) was removed from small antral follicles with the slicing method, and transferred to Medium 199. COCs were placed in a maturation medium for 24 hours, and were reached to metaphase stage Π (nuclear maturation). The experiment was examined in a completely randomized design with five treatments included: control, 75, 37.5, and 18.75 μM of Diazinon, and 0.5 μM of DMSO. The results showed that the addition of different concentrations of Diazinon in the goat maturation medium, significantly decreased the maturation rate (P <0.05) compared to the control treatment, and also it led to a decline in the gene expression of CYP11A1, 17βHSD, CYP19 in cumulus cells. However, the expression of StAR gene was increased. Therefore, it can be concluded that Diazinon has a disruptor effect on oocyte maturation rate, and expression of steroidogenic genes in cumulus cells.