مجله تولیدات دامی
سال بیست و یکم شماره 2 (تابستان 1398)

This experiment was carried out to identify lncRNAs associated with skeletal muscle of the Isfahan native chicken and the Ross 708 commercial broiler chicken. To do this, after extraction of RNA from the breast muscle samples at the age of 28 days, paired-end sequencing was performed using the Illume Hiseq 2000 platform. Hisat2 software was used to align the clean reads to the chicken reference genome and the Stringtie software was used to assemble the transcripts. A total of 1097 lncRNAs were identified as 925 of which were intergenic and 172 were intronic. Also, the number of novel LncRNAs in intergenic and intronic groups were 432 and 128, respectively. Differential gene expression analysis led to the identification of 19 genes and 20 transcripts differentially expressed lncRNAs between two groups. Syntenic analysis showed that differentially expressed lncRNAs are located near by 45 protein encoding genes. Of these, the expression of five gene coding proteins (SCD gene in commercial chickens and GALNT15, KLHDC4, USP7 and ASB1 genes in native chicken) - whose expression was consistent with the expression of their lncRNA - were significantly expressed between two breeds. Functional enrichment analysis of these genes showed that all of them are involved in the skeletal muscle growth. The results of this study showed that the identified lncRNAs probably have the potential to regulate the genes involved in skeletal muscle growth. In this regard, they possibly cause the differences in growth rates between the two chicken breeds.

This research was conducted with the aim of estimation of environmental factors affecting survival and estimate the genetic parameters survival from 1 to the last recording date in Zandi sheep. The survival records of 9558 Zandi sheep from 273 rams and 2328 ewes collected by Animal Breeding Center of Iran during the 25 years (1987 to 2011) were used in the analysis. The effective factors on survival and culling risk were estimated by Survival and cmprsk package. Estimation of variance components was performed by using of exponential distribution for censored dates by the fitting of model with additive genetic effect (model 1) and joint additive genetic and maternal permanent environmental of effects (model 2) under Bayesian approach and Gibbs sampling. A total of 1000000 samples with a burn-in of 100000 and a sampling interval of 75 were generated to estimate the posterior distribution of variance components. The results showed that year, month, birth weight, type birth, sex (P<0.001) and dam age (p<0.01) had significant effect on survival trait. the direct heritability of survival trait using models 1 and 2 was 0.184( 0.136-0.264) and 0.162( 0.120-0.202), respectively. the proportion of permanent variance to phenotypic variance was  0.046( 0.063- 0.031). According to the results of this study, genetic improvement of survival trait in zandi lamb is possible by genetic selection and the culling risk reduction is effective via management of environmental factors.

In this research, the effect of in ovo injection of egg yolk of native Khazak chicken into the egg yolk of the commercial Ross 308 strain at prior to incubation on some metabolic-related parameters were tested in the resulting progeny. The search parameters included feed intake, feed conversion ratio, some of serum biochemical parameters, malondialdehyde concentration as well as relative expression of AMP-activated protein kinase (AMPK) and Neuropeptide Y (NPY) genes in progeny's brain tissue. To achieve this goal, 320 fertile Ross 308 eggs were equally allocated in a completely randomized design into two experimental groups, those injected with Khazak yolk (Test) and control group. Blood and tissue samples were collected at the end of experiment and evaluated for the parameters noted. Compared with the control group, Khazak egg-yolk injection resulted in a significant improvement in the feed conversion ratio as well as significant decreases in serum triglyceride, triglyceride/HDL-C ratio, relative visceral fat mass content and levels of AMPK expression in the progeny's brain. In contrast, Khazak yolk injection had no effect on the 45-day body weight, cumulative feed intake, relative brain weight, serum glucose, cholesterol and LDL-c levels but also had no effects on malondialdehyde concentration and NPY expression in progeny brain tissue. According to the results of this study, the injection of native Khazak egg yolk into the yolk of the commercial Ross 308 eggs have effectively improved the feed efficiency and reduced AMPK expression in the diencephalon region of the progeny's brain.

The aim of this research was to study the feeding value of Lactuca Serriola at different harvesting stages and comparison of different models for prediction of its lag time. The forage was cut at tow growing stages before and after bloom and chemical composition, degradability and gas production parameters were compared with alfalfa hay. Also lag time of experimental forages was determined. The crud protein and NFC concentration were the lowest and NDF and ADF content were the highest after bloom compared with alfalfa hay (p<0.05). potentially digestible fraction (b) of DM increased by enhancement of the growing stage od Lactuca Serriola (p<0.05). effective degradability (ED) and gas production potential before bloom stage were significantly higher than the other experimental forages (p<0.05). Results obtained from prediction of lag time showed that the lag timewas the highest before bloom of Lactuca Serriola (p<0.05). In conclusion, Lactuca Serriola ( before bloom) could be considered as a good potential forage source in ruminant nutrition.

The purpose of this study was to develop multiple linear regression (MLR) model to predict the nitrogen-corrected true metabolizable energy (TMEn) value of wheat bran. The amount of crude fat, ash, crude protein, crude fiber (all used as % of DM) and TMEn (Kcal/kg DM) were measured in 25 wheat bran samples with 4 replicates. The force-fed method has been used to estimate TMEn and excreta were collected for 48 h. There were significant (P < 0.001) differences in chemical composition and TMEn of wheat bran samples. The average crude fat, ash, crude protein, crude fiber and TMEn content of samples was determined to be 4.80, 5.68, 16.23, 8.60 (all used as % of DM) and 2062 (Kcal/kg DM), respectively. The calculated MLR model to predict the TMEn value (Kcal/kg) based on chemical composition (% of DM) was obtained as follows: TMEn = 2364 + (19×crude protein) + (46.1×crude fat) – (63×crude fiber) – (51.1×ash). The R2 value revealed that developed model could accurately predict the TMEn of wheat bran samples (R2=0.82). Crude fat and crude protein had a positive effect on TMEn, while ash and crude fiber had a negative impact on TMEn. The sensitivity analysis on the model indicated that dietary crude fiber (%) is the most important variable in the TMEn, followed by dietary ash, crude fat and crude protein. The results suggest that the MLR model may be used to accurately estimate the TMEn value of wheat bran from its corresponding chemical composition.

In order to determine the effect of non-starch polysaccarides on performance, energy and protein efficiencies and carcass characteristics of broiler chicks, an experiment was conducted in three periods of starter, grower and finisher period, using 420 one-day old Ross 308 broiler chicks from both sexes in a completely randomized design with seven treatments, six replicates and 10 chicks per replicate. The experimental treatments were basal diet, diets containing 0.10 and 0.20 percent of Saccharomyces cerevisiae yeast, diets containing 5 and 10 percent of wheat bran, diets containing three and six percent of soybean hull. The results of the experiment showed that the control treatment had the lowest feed intake during the whole period of breeding (P<0.05). The highest feed intake was related to 10 percent wheat bran and levels of 3 and 6 percent soybean hull (P<0.05). Treatments containing 3 percent soybean hull showed the highest daily weight gain (P<0.05) during the whole experiment. There is no statistical difference for the feed conversion ratio during the whole trial period. The highest relative energy efficiency related to yeast levels were compared to treatments containing wheat bran and soybean hull (P<0.05). The lowest relative energy and protein efficiency was related to 10 percent wheat bran compared to control treatment (P <0.05). The results of the experiment showed that the use of two tenths of yeast, 10 percent wheat bran and six percent soybean hull in the diet of broiler chickens is recommended.

The aim of this study was to determine energy requirement for maintenance (MEm) and to estimate efficiency of energy utilization for gain (kg) using comparative slaughter technique (CST) and relative growth index (RGI: gain/BW0.75) in growing turkey chicks from one to four kg of live body weight (LBW). Forty male turkey chicks (24 days of age, 800 ± 93 g LBW) were fed a standard diet (12.3 MJ ME) up to 4 kg of LBW. Apparent metabolizable energy (AME, and AMEn), nutrient digestibility of the diet, and energy balance were determined at two and three kg of BW. In CST, twenty chicks were randomly killed at four stages (five birds at each stage) at 1119 ±60, 2539 ±93, 3528 ±68, 3957 ±82 g of body weight, and the chemical composition of carcass were measured. Maintenance energy requirement (MEm) and efficiency of energy utilization for gain were determined by linear regression in CST. In RGI, the MEm and energy for growth were estimated by a regression of ME intake and relative daily gain. The results showed that in CST, MEm and efficiency of energy utilization for gain were 450 (kJ/kg BW0.75/d), and 56% respectively. In RGI, the MEm and energy for growth were 3.66 (kJ/g BW0.75/d), and 10.4 kJ per g gain. In conclusion, using RGI method is recommended to estimate energy requirement for maintenance and growth in growing turkey due to its simplicity.

Two experiments were conducted to determine the nutrient ileal digestibility of raw date pit (RDP) and fermented date pit (FDP) as well as their effects on performance and some bloody traits in broiler chickens,. The first experiment was conducted in a completely randomized design with 72 male broiler chicks, three treatments and six replicates (four chicks each) . The treatments consisted of a corn – soybean diet and two experimental diets which prepared by replacing RDP and FDP to basal diet at 25 %. The second experiment was performed in a 2× 4 factorial arrangement along with a control treatment in completely randomized design in a population of 540 day old broiler chickens in nine treatments with five replicates (12 chicks each). Dietary treatments included a diet without date pit (control), and diets containing two, four, six and eight percent of RDP or FDP. The digestibility of crude protein, fiber and ash in the FDP were higher than RDP (p<0.05). Feeding broiler chickens with FDP compared to RDP, improved weight gain (2110.5 g vs 1991.3 g ) and increased feed intake (p<0.05). The blood cholesterol and LDL-c decreased in chickens fed by FDP compared to RDP (p<0.05). According to the results of this experiment fermentation of date pit increases digestibility of its nutrients and improves weight gain of broiler chickens.

This study aimed to evaluate the effect of L-arginine on qualitative characteristics and fatty acid profile of Ross 308 aged broiler breeder roosters’ sperm. Twelve breeder roosters at age of 52 week were used in a completely randomized design with three treatments and four replicates in each treatment for eight consecutive weeks. Experimental groups were consisting diets with levels of 0.52 (Ross recommendation 308), 0.68 and 0.83 present of arginine amino acids. Semen collection was performed every 14 days and in weeks 54, 56, 58 and 60 were tested. At the end of the trial, fatty acid profile of sperm was also evaluated. On week 56, semen volume in roosters with 0.68 present arginine was higher than other treatments (P<0.05). On week 60, levels of 0.52 and 0.68 percent arginine in semen volume, percentage of  total and progressive motility were higher than the level of 0.83 percent of arginine (P<0.05). On week 58, the percentage of abnormal sperm were lower in 0.68 and 0.83 percent arginine treatment compared to 0.52 percent arginine (P<0.05). Semen concentration, sperm plasma membrane functionality and sperm fatty acid profile were not affected by treatments used in this study. It can be concluded that 0.68 percent of arginine (30% higher than recommendation) of diet improve some qualitative sperm parameters in aged broiler breeder roosters.

Trend in body weight, thyroid hormones and some blood metabolites changes in broiler breeder hens after the peak egg production was studied. Blood samples from 20 Ross 308 broiler breeder hens, were investigated from 47 to 55 weeks of age. Plasma lipid profile including cholesterol, triglyceride, lipoprotein LDL, lipoprotein HDL, and also glucose concentrations were measured every two weeks, and plasma concentrations of triiodothyronine (T3) and tetradothyronine (T4), aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) were measured at the beginning and at the end of the experimental period. Results showed that body weight and plasma concentration of glucose, triglycerides, cholesterol, and LDL were increased, and concentrations of HDL were decreased (P<0.05) over the experimental period. Plasma T4 concentrations were decreased with age of the birds (P<0.05), while T3 concentrations were not affected. Plasma GOT and GPT enzymes activities were increased over the experiment period (P<0.05). In general, by increasing of age and subsequently body weight of breeder hens, several major changes have been occurred in blood metabolites and metabolic hormones which could reduce production and reproduction of broiler breeder flocks.

In the current study, immunohistochemical localization of Ghrelin was investigated in placenta tissue of Holstein cows. In order to localization of Ghrelin, pregnancy content of 5 cows were collected in abattoir and transferred to the laboratory. After, placenta separation, paraffin blocks were prepared. Mouse monoclonal anti-ghrelin antibody as the primary antibody and donkey anti-rabbit IgG (HRP) Polyclonal antibody as the secondary antibody were used to localise ghrelin in bovine placenta immunohistochemically. In the present study, to set up the immunohistochemistry test, the ram's testicular sample that existence of ghrelin had previously been confirmed in it,, was used as a positive control. The results indicated that immunoprooxidase reaction was performed in positive control. Also, the serum of rabbit was used as negative control instead of primary antibody. The results demonstrated that the antibody was specific for ghrelin and no immunoprooxidase reaction was observed in negative control. The results showed that ghrelin is expressed in mono and syncytium multinuclear trophoblast cells of bovine placenta, so that the immuno-peroxidase reaction was observed in mono and syncytium multinuclear trophoblast cells in bovine placenta. In general, according to the results of the current study, it can be concluded that ghrelin is expressed in the bovine placenta tissue; however, future studies should focus on the precise role of the hormone in the placenta during pregnancy.