فصلنامه تحقیقات تولیدات دامی
سال نهم شماره 2 (تابستان 1399)

In this study, transcriptome data were used to identify the genes involved in embryo elongation of dairy cattle and the inter-gene interactions to evaluate the important functional modules during this process. The growth, successful development, and survival of the embryo are the most important needs of the dairy industry. The majority of pregnancy loss occurs during the first weeks, especially at the embryonic elongation stage. Thus,in order to better understanding of the molecular basis of this process, we undertook the transcriptome profiling of endometrial cells of pregnant versus non-pregnant cows, during this period. After preprocessing and analysis of microarray and RNA-Seq data and combining the results, gene interactions were investigated using data mining approach. Finally, by comparison of the endometrial profiles, reconstruction of the network and search for important modules, we found four significant functional modules. The most important genes contained ANKRD54, ADAMDEC1, PTN, MT1A, LIMS2, MT1E, CPA3 and MTPN. According to this study, we suggest that identified modules can be used as markers for embryonic growth, elongation, development, secretion of uterine luminal fluid, immune response and embryo survival.

In this study, effect of the reference population size and the number of missing single nucleotide polymorphisms (SNPs) on imputation accuracy was assessed. The QMSim software was used to create a reference database of 1000 simulated animals. Two datasets were created from the database reference: The first dataset (A), included original genotypes, containing the missing SNPs (52,000 SNP markers), and the second one (B) included the same genotypes without the missing data (37,000 SNP markers). In both datasets, animals were simulated for a reference population with the size of 100, 250, 500 and 750. The deleted SNPs were simulated randomly in both datasets with the proportion of 15%, 30%, 55%, 70%, and 95%. The accuracy was determined based on the correlation between the original SNP values before deletion and its values after imputation. The results of this study showed that the accuracy of the imputation was influenced by the size of reference population and density of the deleted SNP markers. By increasing the reference population size from 100 to 750 animals in both datasets, the average accuracy of the imputation was increased. The highest accuracy in the reference population of 750 animals was from 0.89 to 0.98 in dataset A and 0.90 to 0.99 in dataset B. Generally, the results showed that if the size of the reference population is sufficient, the imputation accuracy does not much change, despite large number of missing SNPs.

In this study, data from 1882 ewes, including 3351 lambs born, was used as litter size trait in Afshari sheep breed. The data were collected from 2000 to 2016 by the research station at Zanjan University. The data were analyzed by ASReml software via threshold model in six different models. Fixed effects of year and season, age of ewe, number of parturition and genetic group [at five levels including pure Afshari, 50% Afshari (F1), 75% Afshari (B1), 87.5% Afshari (B2) and 93.75% Afshari (B3)] were significant (P<0.05). Heritability and repeatability were estimated to be as 0.08 and 0.17, respectively. Genetic trends of this trait, in two periods between 2000 to 2006, before the gene introgression design as first period, and from 2007 to 2016, after the introgression as second period, were 0.004 (P>0.05) and 0.059 (P<0.05), respectively. Also, the phenotypic trends were 1.37 (P>0.05) and 1.69 (P<0.05) for two periods, respectively. The results showed that the FecB gene transfer increased the litter size. Consequently, because of the direct relationship between the more profitability of flock and the increase in the number of lambs born, the gene transfer design will be followed and more welcomed by sheep breeders. Therefore, genetic parameters and genetic trends estimation of litter size in this flock can be effective for developing continues genetic breeding strategy.

The aim of the current study was to investigate the effect of removing age at sexual maturity in native fowl breeding goal. Therefore, a deterministic simulation for single stage selection with discrete generations was used to estimate genetic and economical responses as well as inbreeding rate. The first aggregate genotype consisted of body weight at eight weeks of age, average of egg weight at 28, 30 and 32 weeks, egg number and age at sexual maturity. In this case, genetic gains for body weight at eight weeks of age, average of egg weight at 28, 30 and 32 weeks and egg number were 53.19, -0.207 and 13.02, respectively. The second program was the same as the first whereas only age at sexual maturity was excluded. This is followed by decreasing genetic gain for egg number. On the other hand, accuracy of selection also decreased. Decreasing accuracy of selection is related to increase breeding goal variance. Changing the number of selected sires in breeding program showed the selection proportion of two percentages in sires was led to optimal genetic gain for breeding goal’ traits. In this case, inbreeding coefficient is about one percent which is optimum for poultry breeding programs.

One of the new methods for drinking water disinfection in poultry farms is the use of silver nanoparticles (AgNPs). Anti-bacterial effect of silver had been known for disincentive activity of AgNPs. An early low fertility syndrome has been reported in broiler breeding farms. The aim of this study was to evaluate the effects of AgNPs on reproductive performance of male quails as a laboratory model. Twenty-four male quailswere used in four treatments with six replications. The treatments consisted of 0, 12, 36 and 108 ppm of silver nanoparticles, which were consumed in drinking water. Then blood samples and testes were collected after 42 days and body weight, daily sperm production, paired testes weight (g), gonado-somatic index (GSI), testosterone serum concentration and testicular histopathology indices were evaluated. There was significant decrease in the testes absolute weight in two groups of 36 and 108 ppm AgNPs (6.3-6.5 g) compared with control group (8.8 g, P<0.05). The GSI was also significantly (P<0.05) declined in 36 ppm AgNPs group (2.92±0.46%) as compared with control group (3.74±0.47%). The 108 ppm AgNPs group caused a dramatically reduction of daily sperm production (110.6±28.1×106) as compared to control (327.7±94.4×106, P<0.05). One of the most important histopathological findings was a depletion of cells in the seminiferous tubules of testis and spermatogenesis chain and a low density of spermatozoa in the proximal and distal efferent ductules in the 108 ppm AgNPs concentration. The results indicated that silver nanoparticles reduced the male reproductive performance in male quail.

The effect of omega-3 fatty acids on performance and physical characteristics of eggs in laying hens under physiological stress was evaluated using 96 LSL-Lite layers in a 2 × 3 factorial experiment with two levels of stress (stress and non-stress) and three levels of omega-3 fatty acids (0, 0.24 and 0.48% of diet) in a completely randomized design for 70 days. From age of 35 to 40 weeks, birds were fed with basal diet and various levels of omega-3 fatty acids, at 41 weeks of age. Physiological stress was induced by adding 1.5 mg dexamethasone/kg of diet for one week. Dexamethasone was then removed from the diet and the birds were fed with pre-stressed diets for three weeks (post-stress period). Percentage of production, feed intake, egg mass, as well as physical traits of eggs in stress and post-stress periods were evaluated. During the stress period, the percentage of egg production, weight and egg mass, shell thickness decreased under stress while feed conversion ratio increased (P<0.05). Feed intake of stressed birds fed diets containing different levels of omega-3 fatty acids was lower than other groups (P<0.05). The lowest yolk index was observed in the stressed birds fed diets containing levels of 0.24 and 0.48 % omega-3 fatty acids. In the post-stress period, the egg production, egg mass, feed intake in birds that experienced stress was lower than non-stressed birds and had higher feed conversion ratio (P<0.05). During this period, the shell thickness of the stressed birds receiving level of 0.48% of the omega-3 fatty acids was lower than other groups (P<0.05). In general, the use of omega-3 fatty acids in stressed laying hens with the intensification of reduced feed intake can increase adverse effects of stress on the performance and egg quality.

This study was conducted to evaluate the effect of Aloe vera gel and conjugated linoleic acid supplement feeding on performance, blood metabolites and immune parameters in Holstein calves in a completely randomized design with a 2×2 factorial arrangement. This study was carried out using 24 male and female Holstein calves (with average age of 1-10 days and 38±8 kg weight) with four treatments and six replications for 60 days. The treatments were: (1) basal diet including starter and whole milk (control), (2) basal diet + 250 mg/kg body weight Aloe vera gel, (3) basal diet+20 g/kgDM complementary conjugated linoleic acid (CLA) and (4) Basal diet+250 mg/kg body weight Aloe vera gel+20 g/kgDM of CLA. The Dry matter intake, weight gain, feed conversion ratio, blood parameters and immune and health factors were measured. Results showed that there were no significant differences between the control and other groups in terms of feed intake and performance of Holstein calves. The interaction effect of Aloe vera gel and CLA was significant on blood glucose concentration and calves receiving 250 mg Aloe vera gel had the lowest glucose concentration (88.33 mg/dL) (P>0.05). On the other hand, the effect of time on white blood cell, lymphocyte and monocyte was significant (P<0.05) and using 20 g CLA increased blood monocyte (5.33%) compared with no CLA treatments (3.58%; (P<0.05). In general, the interaction effect of aloe vera gel and CLA supplementation was not significant on performance and health status of Holstein calves.

Food- feed competition is one of the main challenges in the sustainability of livestock production systems. From this point of view, it is important to identify the nutritional value of agricultural waste as an alternative for animal feeding. The current study was carried out to evaluate nutritive value, phenolic compounds and in vitro digestion characteristics of different parts of Berberis Vulgaris plant. The experimental treatments included: 1) alfalfa hay, 2) barberry branches, 3) leaves before barberry harvesting, 4) leaves after barberry harvesting and 5) a mixture of branches and leaves (in the ratio of 60:40). The samples of barberry harvest wastages were manually prepared and sun-dried. The chemical compositions and phenolic compounds of samples were determined according to standard laboratory methods after milling samples and gas production of samples was assessed at zero, 2, 4, 8, 12, 16, 24, 48, 72 and 96 hr. The results revealed that dry matter, organic matter and ash content were similar among treatments. The highest crude protein was observed in barberry leaf; also the main tannins in barberry wastes were hydrolysable. Gas production rate (c) was the same among treatments; however, the highest gas production potential (b) was observed in leaf (P<0.05). Feed fermentation efficiency, organic matter digestibility, metabolizable energy and net lactation energy were also higher in barberry leaf than alfalfa hay (P<0.05). In conclusion, barberry harvest residues (except branches) has acceptable nutritional value and due to its large volume in South Khorasan province, the possibility of industrial scale preparation and lower cost than alfalfa, can be used as a replacement for current forage like alfalfa in ruminant nutrition.