مجله علوم دامی ایران
سال چهل و نهم شماره 2 (تابستان 1397)

The aim of this experiment was to study the effects of long-term induced hyperthyroidism on the body weight and egg production. In addition the relationships between hyperthyroidism and some reproductive parameters were studied. A total of seventy 47-week-old Cobb 500 breeder hens were randomly allotted to two treatment groups (5 replicates of 7 hens each). Thyroxine was orally administered to the hyperthyroid group (0.3 mg/bird/day) for 100 consecutive days during which the body weight and egg production were recorded on a weekly basis. Effect of hyperthyroidism on plasma T4 levels was significant; but, the T3 level was not affected. Results indicated a significant decreasing effect of thyroid hormones on body weight. Thyroid hormones had no effect on egg production; however, the treatment × time (wk) interaction effect was significant on egg production. Ovarian and oviductal weight were not different between the control and hyperthyroid hens. Administration of thyroxine to breeder hens decreased the diameter of F1 follicles.

This experiment was conducted to investigate and identify the isoforms related to the structure of muscular proteins between Isfahani native and Ross commercial chickens with different growth rates. We extracted total RNA from breast muscle samples of two groups at end of 4 weeks of age. After paired-end sequencing of samples using the Illumina Hiseq 2000 platform, Hisat2 was applied to align clean reads to chicken reference genome. Then, Cufflinks package was used to assemble transcripts and identify significantly differentially expressed genes. The statistical comparison of the isoforms between two groups revealed 259 isoforms with significant difference in expression, of which 161 isoforms were up-regulated and 98 isoforms were downregulated in commercial chickens. Among the commercial chicken isoforms, four genes (ACTC1, ATF3, CYR61 and FABP4) were upregulated with two different isoforms. In addition, in commercial chicks, the frequency of isoforms associated with slow contraction fibers was greater than that of rapid contraction fibers. Functional study showed that the isoforms in commercial chickens were more related to cell proliferation and differentiation, hypertrophy growth and biosynthesis of muscle proteins, whereas in native chickens, mainly they were associated to immune processes, carriers of ions and metals, binding to metals, DNA and RNA, and factors contributing to degradation of muscle proteins. The results of this study showed that such changes may have been able to strengthen the ability to maintain and overcome the severe environmental and nutritional conditions during the developmental period of the chicken by reducing the level of requirements and enhancing immunity and adaptability in native chicken.

The objective of this study was to determine the effects of different sources of fatty acids on the performance and liver activity indices of Holstein cows during the transition period. Thirty-five cows were randomly assigned (from 21 days prepartum to 21 days postpartum) to 5 dietary treatments consisting of a diet containing palm oil (T1) as control, CLA fat supplement (T2), extruded flaxseed (T3), mixes of CLA fat supplement and extruded flaxseed(T4), and sesame oil and sesame meal (T5). The amounts of dry matter intake and milk yields were measured daily and milk composition was measured weekly. Blood samples were collected weekly to determine the concentration of plasma parameters. Feed intake, milk yields and milk composition were generally similar among treatments (P>0.05). Among blood parameters, the levels of urea and total protein affected by treatment in postpartum (P <0/05). The concentration of total protein in group T3 was higher than group T1. The urea concentration in group T5 was higher as compared with group T3. Amount of aspartate aminotransferase in prepartum had a significant tendency between treatments (P<0.1) and the highest amount was observed for group T1. The results of this study showed that CLA supplementation and extruded flaxseed increased total protein and reduced blood urea and has a beneficial effect on the health of the liver during the transition period.

Avian pathogenic Escherichia coli (APEC) is responsible for an extremely wide range of extra intestinal diseases in poultry, including Colibacillosis and Cellulitis. There is the problem of antibiotic resistance all over the world. The aim of this study is the molecular study of antibiotic resistance genes, such as: aac, aad, qnr, tet, anr, sul and determination of antibiotic susceptibility. 83 strains of E. coli of Colibacillosis cases and 34 strains of Cellulitisin cases were gotten from in poultry slaughterhouses in Shahrebabak province within 6 months in 2017. Strains of E. coli were confirmed by biochemical methods. The results of the study showed that 63.85% for the tetA gene, 62.65% for the tetB gene were positive. The abundance of genes qnrs (49.3%), qnrB (24.09%), sul1 (28.91%), dhfrv (31.32%), dhfrA (26.50%), aac (3)-1(25.66%), aadA (22.89%), floR (28.91%), sul1 (33.13%), qnrA (12.30%). None of the specimens was positive for blaoxa, blaCTX, blasHV, blaTEM, genes. In this study, it was found that all of the suppositories were resist ant to one or more antibiotics between 40% and 90%. The highest resistance to antibiotics was tetracycline, sulfamethoxazole, chloramphenicol, terimetoprim. In this study, antibiotic resistance was found to be due to the presence of resistance genes. Recognition of resistance pattern and microorganisms susceptibility to antibiotics have an effective role on correct and suitable selection of antibiotic and infection control.

The aim of this research was to estimate (co) variance components, heritability, genetic and phenotypic correlations between different stages of lactation for milk fat to protein ratio (FPR) of Holstein dairy cattle in Iran using a random regression model. The data used included 1302984 test day records of 149440 cows in 307 herds that were calved during the years of 1996 to 2017. Contemporary groups herd-month of recording (herd test day (HTD)), the age at the calving and lactation curve were considered as fixed effects in the model. Additive genetic and permanent environment effects were fitted by the Legendre’s orthogonal polynomial with forth order. The results showed that FPR had an adequate genetic variation, but due to the high environmental variations, the estimates of heritability were low in different stages of lactation and varied from 0.06 to 0.08. Genetic correlations of FPR in different stages of lactation were in the rage of 0.24 to 0.99. The genetic correlations between first and second stage was high (0.84); but its decreased dramatically with other stages and ranged from 0.24 to 0.52. However, the genetic correlation between the other lactation stages was gradual decreased with increasing the interval between them. The phenotypic correlations between lactation stages were lower than the genetic correlation and were observed in the range of 0.02-0.25. Genetic improvement is possible for FPR because of genetic variation; however, more daughters are needed for each sire to achieve appropriate accuracy of breeding values due to low heritability.

This experiment was conducted in a completely randomized design with 2×3 factorial arrangement with two levels of corticosterone injections (oil injection and corticosterone injections) and three levels of probiotic supplementation (1- without probiotic, 2 and 3- supplemented with 0.8×105 and 1.6×105 spores of Bacillus subtilis per gram of feed, respectively) to modulate stress induced by corticosterone injection using probiotic admimistration in broiler chicks. Each of 6 treatments replicated 4 times of 12birds per replicate.At 7 to 9 and 25 to 27 days of age, the chicks received one of the subcutaneous injections corn oil with/without CORT at 2 mg/kg BW twice per day. Corticosterone injection decreased the relative weight of intestine and its length at 28 and 42 days of ages (P<0.05). Relative weight of the breast was lower in corticosterone injected groups than in the oil injection groups (P<0.05). Villi height of different parts of the intestine and antibody levels against Newcastle disease decreased significantly with corticosterone injection.Adding probiotics increased the length of the villi and relative weight of the intestine. Feed to gain efficiency and average daily weight gain increased significantly in response to probiotic supplementation (P<0.05). Total coliforms and lactobacillus populations were not affected by corticosterone injections, but adding probiotic had a significant effect on ileal populations of these bacteria (P<0.05). Overall, the results of this study indicate a positive effect of probiotic on performance and intestine structure of broiler chicks under stress induced by corticosterone injection.

The purpose of the present study was to estimation of (co)variance components and genetic parameters of the growth curve in crossbred population. For this purpose, body weight records were fitted through the Gompertz curve and curve parameters were estimated. The final weight (Wf), hatch weight (W0), mature rate index (K), age (ti) and weight (Wi) in inflection point and growth rate in different days for all of the birds were predicted by Gompertz model. The estimated of (co)variance and genetic parameters were performed using a multi-trait animal model through Gibbs sampling. Heritability of the growth cure parameters including final weight, hatch weight, mature index and weight and age in inflection point was 0.335, 0.269, 0.273, 0.291 and 0.397, respectively. Also, the heritability of growth rate traits from hatch to 45 days was estimated high and varied between 0.311 to 0.424. The genetic correlation between hatch weight with mature index and final weight was positive (0.14 and 0.24), but the genetic correlation between hatch weight with age and weight at inflection point was negative (-0.24 and -0.12). The genetic correlation of the mature index with hatch weight, mature weight, age and weight at inflection point was negative. Genetic correlation of the mature index with growth rate in the early ages of bird was positive and it was estimated medium and negative for late. The weight at inflection point had the positive genetic correlation with most of growth rate traits and the change trend from beginning to end of growth period was ascending.

The aim of this study was to determine genomewide linkage disequilibrium (LD), Haplotype block and effective population size using the information obtained from 243 Azarbaijani breed buffalo using a high density SNP panel (Axiom® Buffalo Genotyping 90K). After quality control of SNP markers data, 62,141 SNP markers remained for identification of linkage disequiliberum, haplotype blocks and effective population size. LD was measured by the square of the correlation coefficient (r2) between alleles. The maximum LD measured by r2 varied from 0.25 to 0.29 at a distance of < 2.5 kb, and the minimum average values of r2 varied from 0.012 to 0.014 at distances ranging from 900 to 1000 kb, clearly showing that the average r2 reduced with the increase in SNP pair distances. Overall, 1693 blocks were observed through the genome. Eleven percent of all SNPs were clustered into haplotype blocks, covering 202 ±3.4 Mb of the total autosomal genome size. Effective population size (Ne) was estimated based on expected linkage disequilibrium. Ne was estimated to be 422 in our population.

The aim of this research was to utilize a simple, rapid, cheap and safe method for sex determination of newly born canaries through feather to help accurately breeding this bird. The external morphology of males and females of many birds such as canary are fairly similar to each other, Therefore, determining their sexes is very difficult. The different length of CHD (chromo-helicase-DNA-binding) gene in Z and W chromosomes can recignized by using molecular technique based and PCR method, for the sex determination of young birds. In this study, blood and feathers samples of 140 canaries from 10 different breeds were used and their DNA were extracted. It should be mentioned that for PCR, at first 5 primers designed and finally 1 specific primer were confirmed and used. The results showed that the amplification of a fragment with the length of 252 bp for males (ZZ) and two fragments with the lengths of 252 and 309 bp for female (ZW). The bands had a length difference of 57 bp. The DNA sequencing of these two fragments was done for the first time, the sequence of these two fragments of the CHD gene in canary species was submitted and accepted in the NCBI site under the names of CHDZ-1 and CHDW-1 with the accession numbers of MG679825.1 and MG679826.1.

The aim of this study was to investigate the effect of zinc and copper adding to diet of late-pregnant Mehraban breed ewes, on blood and milk minerals profile, lambs growth performance and some blood parameters. Seventeen ewes with 3-4 years old, 45 days before delivery were divided into 3 groups. Treatments includes: treat1) basal diet without supplement (containing 18.98 ppm Zn and 7.51 ppm Cu); 2) basal diet+30 ppm Zn as zinc sulfate, and 3) basal diet+30 ppm zinc as zinc sulfate and 8 ppm Cu as copper sulfate.Lambs were weighed at birth and at 10, 20 and 30 days of age. Lambs were raised with their dams during the experimental period. Blood samples of ewes were collected at -45, 0 and +30 days of delivery and lambs at 10 and 20 days of age. Milk sample was collected at 0, 15, 30 days after delivery. Dietary supplementation of zinc and copper significantly increased plasma (ewes and lambs) and milk zinc and copper concentrations (P<0.05), however, milkiron and also serum Calcium and Phosphorus concentrations were not affected (P>0.05). In treat-2 and 3, lambs body weight, daily gain, red blood cells count, hemoglobin concentration, plasma T3, zinc and ALP concentrations were significantly higher than control group (P<0.05). The concentrations of glucose, creatinine, total protein, albumin, globulin, lactate dehydrogenase, triglycerides, cholesterol were not affected by treatments (P>0.05). The results showed that adding 30 ppm zinc to pregnant ewes' diet result in increase plasma and milk zinc concentrations and finally lambs growth performance.

The aim of this study was to investigate the interaction effects between feed bunk spaces and forage particle size on feeding behaviors of female Holstein calves. This study was done on 40 Holstein heifers aged 8-12 months and average mean weight 295.62±32.86 kg in a factorial change over design 2×2 (four periods with a length of each period of 25 days). The sole differences between treatments was related to forage (alfalfa hay and wheat straw length) as these forage were cut off by cutter with 3 cm pore size sieve (fine diet) and 6 cm pore size sieve (coarse diet) before adding to feeder mixer wagon. Treatments in this experiment included: 1) treatment with 24 cm of feed bunk space and forage with fine particle size (24/fin), 2) treatment with 24 cm of feed bunk space and forage with coarse particle size (24/coarse), 3) treatment with 48 cm of feed bunk space and forage with fine particle size (48/fin), 4) treatment with 48 cm of feed bunk space and forage with coarse particle size (48/coarse). The results showed that the feed intake time was higher during 24 hours for treatments with free bunk space (48 cm) compared to treatments with a limited bunk space (24 cm) (p<0.05). The results showed that in case of access of calves to free bunk space, the feed particle size did not affect the intensity of competition, while in the case of a limited bunk space, the intensity of competition for coarse particle size was greater than that of fine particle size (p<0.05).

The aim of this study was to extract genes and probes hub based on Bayesian networks on probe and gene transcriptomic data over different tissues in Bovine species. Using raw probe and gene transcriptomic data in each tissue, genes and probes with the highest expression variances were extracted and fitted to Bayesian networks. The hub genes and hub probes were identified using the ratio of in-and-out degree.The size of the Markov Blanket was different in different networks. This might be indicative of existing of substructures topology of aforementioned network on different tissues. Using gene based network, in muscle (CBR1 and LOC788826); in mammary of (NID2, COL5A2, LOC616942 and FXYD3); in liver (LOC100132279; MGC127133; MBOAT2; CLDN2; ANKRD1; IGFBP1; DGAT2; CKMT1, ISG15, CKMT1), and in the ovary (LOC286871 and INHBA) were extracted as hub genes. It was shown that the hubs were different in different tissues. These results can be used for more accurate bioassays of each tissue. Using probe based network, two genes BOLA-DQB and JSP.1 would have function in liver and uterus tissues. The results of this study can reduce the gap between phonemics-and Genomics distance on investigated tissues in bovine species.

The objective of this study was to estimate the financial losses due to culling and replacement as well as the causes of culling in industrial dairy herds of Isfahan province. Data collected from 4 Isfahan dairy farms including 109896 calving records during the years 2006 to 2017. A bio-economic model was used for financial losses estimation and SAS software for statistical analyses. The rate of culling over the past decade has increased by an average of 1.2% per year (13.1% in 2006; 28.5% in 2016). The average of culling rate in 4 herds was 23.2%. The voluntary culling was only 5.8%. The most significant reasons of involuntary culling were infectious disease (31.4%) and reproduction problems (28.8) that mainly happen in summer. On average, each case of culling led to 17800 thousand Rials losses to dairy cow’s producers. The losses due to the culling of the primiparous were 54% higher than that of cows with multiparous. The losses due to culling in the first month of milking were estimated at an average of 20460 thousands Rials which caused 35% more losses per cow than those milking in the tenth month. The results of this research could be used in cost-benefit analysis of management strategies for cull and replacement of heifers.

The Arab horses are famous for endurance riding, jumping and beauty. Kurdish horses are native to hilly regions of west of Iran and they are suitable for Polo tournament. Kurdish horses are shorter and heavier than Arabian horses. In this study, we use the linkage disequilibrium-based method, XP-EHH statistic, for Identification of regions that have undergone selection in the genome of Arabian and Kurdish horses. For this purpose, genomic DNA from blood and hair samples from 38 Arabian and 58 Kurdish horses were extracted. All DNA samples genotyped by the Axiom MNEC670 array. After data pruning, XP-EHH statistic was calculated. We identified 51 genomic regions (85 genes) in Iranian Arab horses and 7 genomic regions (13 genes) in Kurdish horses showing signatures of selection. We found positively selected genomic regions in the Iranian Arab horses associated with immune system related pathways, milk protein formation, muscle growth and development, vision, nervous system and body size whereas in the Kurdish horses associated with G protein–coupled receptors, growth and maturation of muscle fibers, cellular oxygen homeostasis and skin and hair pigmentation.

This study was conducted to evaluate the effects of type of poultry on apparent metabolisable energy value of two soybean meal (processed and non-processed SBM).In this study, 36 broiler breeder hens (Ross 308, 62 weeks), 72 male broiler chickens (Ross 308, 35 days) and 36 commercial layer hens (Hyline W36, 40 weeks) were used. Dietary treatments were contained a reference diet and two test diets. In the test diets 30 percent of corn, SBM and sunflower oil replaced by processed or non-processed soybean meal. In all three experiments, metabolisable energy of ingredients measured by excreta collection using celite as a marker. The results indicated that the AMEn ofprocessed and non-processed soybean meal for broiler breeder hens was higher than broiler chickens and commercial layer hens. Our results showed that the AMEn of processed SBM were significantly higher than AMEn of non-processed soybean meal (2626.08 vs 2274.75 for broiler breeder hens and 2466.0 vs 1993.6 for broiler chickens and 2344.46 vs 2079.75 kcal/kg for layer hens). In conclusion, the results showed that the metabolisable energy intake of ingredients were different among different birds and processing could increase the nutritional value of soybean meal.