مجله تحقیقات دام و طیور
سال پنجم شماره 3 (1395)

The main objective of this research was genetic evaluation of dairy cows in Tehran province for 305-d milk production trait based upon 1- first lactation records (scenario one, S1) and 2- first and second lactation records (scenario two, S2). A total of 206,013 records (126,600 first lactation records and 79,413 first and second lactation records) belonging to 126,600 head (representing 2,876 sires and 89,368 dams) in 260 herds was used. The cows calved between 1983 and 2011. Total number of animals in the pedigree file was 218,844 head. DMU software was utilised for estimation variance components (REML) and for prediction breeding value (BLUP). Genetic trends for scenarios 1 and 2 were 16.6 kg (SE=2.42 kg) and 14.9 kg (SE=2.42 kg) per year, respectively and non-significance difference was found between them. Heritability of the trait was 0.281 and 0.247 for these scenarios, respectively. Based on the type of used records, mean accuracy selection of the daughters (0.67 for S1 and 0.69 for S2) were significantly (P<0.0001) different from each other. The findings of the present study revealed that more or less similar genetic trend as well as selection accuracy could be obtained as the genetic evaluation of the cows is undertaken through the scenarios, suggesting that first lactation record could be used to decrease generation interval, and as a consequence, to increase annual genetic gain.

The purpose of this study was to investigate the genetic, phenotypic and environmental trends of growth traits in Shal sheep. In this regard, records were collected on the growth traits of 6692 lambs that were collected from 1997 to 2013 at Shal Sheep breeding station located in Qazvin province. The studied traits included birth weight (6690 records), three months weight (6654 records), six month weight (6662 records), nine months weight (6599 records) and twelve months weight (6528 records). Genetic parameters were estimated using WOMBAT software with limited likelihood method. The genetic, phenotypic and environmental trends of the traits were estimated using the regression coefficient of average breeding values, phenotypic and environmental on birth year, respectively. Direct heritability of body weight at different ages based on the most suitable model for birth weight, three, six, nine, and twelve months were 0.13±0.02, 0.57±0.05, 0.52±0.05, 0.79±0.04, and 0.73±0.05 respectively. Correlation between direct and maternal incremental genetics in all negative traits was obtained. The genetic trend for the traits was -0.86, -10.19, -27.45, -15.73 and -2.44 g/y, respectively. The phenotypic trend was 12.84, -65.19, -57.35, -53.92 and -57.59 g/y, respectively, and also the environmental trends were estimated and environmental trends were 4.33, -21.56, -26.47, -0.98 and -41.91 g/y, respectively. Genetic, phenotypic and environmental trends of all traits were not significant. The results of this study indicate that there is no positive genetic growth of Shal sheep weight traits in recent years. Therefore, appropriate breeding programs are recommended for genetic improvement of the mentioned traits in shal sheep.

Information about mortality of 6426 lambs which were born from 223 rams and 1769 ewes from years 1991 to 2015 in Sarakhs’ Karakul sheep breeding station was used. The trait under study was lambs’ monthly cumulative survival rate from time of birth to one year of age. Frequency of mortality causes and survival distribution function were analyzed using Freq and Lifetest procedures of the SAS statistical software, respectively. The overall lambs' mortality from birth to yearling age was 14.57 percent. The most important mortality reasons were starvation, digestive and respiratory illnesses. The lambs’ cumulative survival rate was 85.4 percent in their first year of life. Regression coefficient of survival from lamb age showed that lamb's survival decreased 0.037% per day. Lambs’ mortality rates were 7.8, 4.06, 1.23 and 1.48 percent in the first, second, third and fourth triplet months of lambs’ life, respectively. The lambs’ highest mortality occurred in 1st, 2nd, 6th and 10th month of age. As mortality rate was highest in the first 3 months of lambs' life, it is suggested to apply better care and nutritional management for the ewes and lambs in this period to increase survival rate of lambs.

The objective of the present study was to determine the extent of BOLA-DRB3 locus polymorphism in a herd of Sistani Cattle and their associations with body weight traits including birth weight, 3, 6, 9 and 12 months, and blood serum biochemical such as total protein, albumin and globulin. For this, blood samples collected randomly from 143 Sistani Cattle in a research herd at the Sistani Cattle Research Centre. DNA extraction from complete blood samples was performed with optimized saline method. The amplification of the 284-bp fragment of the BoLA-DRB3 gene was performed in two steps. In the first step, the HLO30 and HLO31 primers were used and in the second step the HLO30 and HLO32 primers were used. Then, the amplified fragment was digested by HaeIII enzyme. The digestion products were resolved on electrophoresis of 3% gel agarose. Population and genetic structure was calculated with POPGENE software and probable genotype patterns association with body weight traits and blood biochemistry traits were implemented by fixed linear model. The results of this study revealed two alleles and three genotypes as aa, bb and ab in locus of BOLA-DRB3.2 in Sistani cattle. Genotype frequencies of aa, bb and ab were 30, 41 and 28%, respectively, and alleles frequencies of a and b were calculated 44 and 56%, respectively. In this experiment, the Shannon index (I), Nei's index, heterozygosity was observed and the expected heterozygosity were calculated 69, 49, 28 and 50 respectively. The analysis of likelihood ratio test and X2 in BOLA-DRB3.2 showed that the population of Sistani cattle studied in this study was beyond the Hardy-Weinberg equilibrium. Also, the correlation of different genotypes with body weight traits including birth, 3, 6, 9 and 12 months, and biochemical characteristics of serum were not significant.

This experiment was conducted to evaluate the Response of duodenum histomorphometric characteristics, pH and microbial population of alimentary canal to silver nanoparticles coated on zeolite with 375 Cobb 500 broiler chickens in a completely randomized design with 5 treatments and 5 replicates and 15 birds to each replicate. The examination treatments were: 1) control diet (C) 2) control diet supplemented with 1% zeolite (Z) (3, 4, and 5) control diet supplemented with 1% zeolite coated with 0.25% (NS25), 0.5% (NS50) and 0.75% (NS75) nanosilver. group NS50 increased villi surface area compared with the control treatment and group NS25 (P<0.05). On d 42, groups NS25 and NS50 increased crop lactobacillus population compared with control treatment and group Z (P<0.05). The use of all treatments (Z, NS25, NS50 and NS75) decreased ceca coliforms compared with the control treatment (P<0.05). Also, the all of treatments decreased crop pH compared with the control treatment (P<0.05). Groups NS50 and NS75 decreased ceca pH compared with the control treatment (P<0.05). In conclusion, the results of this study showed that silver nanoparticles coated on zeolite decreased pH and coliforms Harmful bacteria population and increased lactobacillus Beneficial bacteria and the end increased villi surface area of broiler chickens and it can be considered as a growth and health promoters.

To evaluate the effect of Kombucha on blood glucose, lipids profile and performance 200 male broiler chicks' strain Ross 308 were applied for 42 days in five treatments and four replicates and 10 chicks for each replicate. Diets composition were equal in all treatments and water was different among groups receiving Kombucha fermented tea (0%, 10%, 20%, 30%, 40%). At the end of each week, chicks were weighed and the average weight and feed intake and feed conversion ratio for each treatment was calculated. Blood samples were collected from jugular vein and the levels of glucose, total cholesterol, LDL (low density lipoprotein), HDL (high density lipoprotein) and triglyceride was measured. Statistical analysis was carried out with SAS software. Result showed that the concentration of triglyceride significantly decreased by the levels of 40% of Kombucha compare to the control group (P<0.01). But Kombucha fermented tea did not have significant effect on total cholesterol, glucose, LDL and HDL (P>0.05). In addition, feed intake, weight gain and feed conversion were not affected by Kombucha. Therefore, according to the results of this study, the use of Kombucha fermented tea in poultry diet is not economical and is not recommended.