مجله تولیدات دامی
سال بیست و دوم شماره 4 (زمستان 1399)

The aim of this study was to identify the genome-wide copy number variations (CNV) in one of the sheep breeds in Afghanistan named Arabic breed, and to study the associations between these regions containing this kind of diversity with different biological pathways. For this purpose, 15 animal samples from different ages were collected from their natural rearing environment in Herat province of Afghanistan and then were genotyped using Illumina Ovine 50kSNP array. After various steps of the data quality control, the genome-wide detection of CNVs was carried out using Hidden Markov Model in PennCNV (version 1.0.3) software. The results showed that all animals used in this study have CNVs in their genome. In total, 306 CNVs were observed for autosomal chromosomes. The total genomic length of CNVs was 128 Mbp and the average CNV numbers per animal was 20.4. After merging overlapped regions, a total of 286 CNVR regions were identified. These genomic regions were then further evaluated using bioinformatics tools for identifying the metabolic pathways associated with them. The results of gene ontology study indicated that many of these regions are associated with different metabolic pathways such as fertility and reproductive performance, body weight and carcass characteristics, immune system development, and skeletal-muscular system.

In order to evaluate the effect of genotype by environment interaction on production traits of Holstein cattle of Iran, first lactation test day records of 344170, 135000 and 156840 of milk, fat and protein yield on 34417, 13500 and 15684 cows and SNP markers of 1935 genotyped bulls were used. The production data were retrieved from the Animal Breeding Center and Productions Improvement of Iran’s database which were collected from 2013 to 2018. To consider the interaction of genotype and environment, mean of temperature-humidity index (THI) in three days before each test day records as continuous environmental effect were retrieved from the 35 closest meteorological stations in the vicinity of 139 Holstein herds from 13 provinces. Variance and covariance components were estimated through a single-trait random regression model with orthogonal Legendre polynomials of second order for days in milk and THI using AIREMLF90 software. The results showed that changes in THI across lactation led tofluctuations in additive genetic variance over time. The change in heritability of milk production traits over lactation followed the same trend as additive genetic variance. The results from cross-validation analysis showed that including genomic information into the predictive model, increased prediction accuracy and including THI information increased unbiasedness. Due to the changes in milk production of daughters of bulls across days and THI , genotype by environment interaction should be considered when selecting bulls under different conditions.

This objective of this experiment was to study the effect of diet containing high (40.7 %) non fibrous carbohydrates on some inflammatory and native immunity related genes expression in lactating Jersey cows. Seven lactating multiparous (2.5 ± 0.5) Jersey cows with 71 ± 3 days in milk and 28 ± 6.6 kg of average milk production were used. All cows received a control diet containing low (34.3 percentage of dry matter) non fibrous carbohydrates content for the first 14 days and then were transfered to a diet containing high (40.7 percentage of dry matter) non fibrous carbohydrates content forone week. Blood samples were collected on day 0 (After 14 days of feeding control diet) and days 4 and 7 after feeding high NFC diet. Relative gene expression of seven genes (IL1-β, TNF-α, MNDA, CD74, TLR2, SELECTIN, TGF1-β) were measured. The results showed that gene expression of the pro-inflammatory cytokines (IL1-β and TNF-α) and anti-inflammatory proteins (MNDA, D74, TLR2, SELECTIN, TGF1-β) was down regulated during feeding of high NFC diet (P<0.05). These data indicated that feeding a high non-fibrous carbohydrates diet caused inflammation and affected immunity system in lactating Jersey cows.

This experiment was conducted to study the effects of inclusion of sucrose with or without calcium salts of fish oil on growth performance, ruminal fermentation and blood metabolites of fattening Holstein steers. Thirty sixth Holstein bull calves (269±57 kg body weight and 7 months of age) were used in a completely randomized design with a 2×2 factorial arrangement for 128 days. Dietary treatments were 1- control, 2- calcium salts of fish oil (Ca-FO) (2.5 % DM), 3- sucrose (SU)(5% DM), 4- SU and Ca-FO. Average daily gain increased with added SU (P<0.05). Diets containing Ca-FOreduced dry matter intake (DMI) and using SU and Ca-FO together increased DMI in this group (P<0.05). A tendency for higher organic matter digestibility obsereved in bulls fed Ca-FO (P>0.05). An increase in ruminal acetate concentration observed using Ca-FO in the diet, although Lower propionate and higher acetate concentrations were observed in rumen fluid of SU provided bulls (P<0.05). Addition of SU increased ruminal fluid pH (P<0.05). Feeding steers with Ca-FO increased plasma concentration of triglyceride and cholesterol (P<0.05). The results of this study showed that replacing corn grain with sucrose could have stimulatory effect on dry matter intake in Ca-FO containing diet, which have positive effects on average daily gain of fattening steers.

To determine the effect of mixed thyme and eucalyptus leaves aqueous’ extract on the performance and health of Holstein suckling calves, an experiment using 32 calves (16 females and 16 males) with 7±3 days old and an average weight of 40.4±3 kg was carried out in a completely randomized design with four treatments and 8 replicate for 70 days. The treatments were: diets with no extract (control); and diets containing10, 15, and 20 ml of extract (50 % thyme + 50% eucalyptus) in consumed milk. In order to evaluate changes in body weight, chest circumference and height, the data were measured and recorded on days 7, 28, 49, and 70 at 10 a.m. To determine the blood parameters, blood samples were taken from the jugular vein on the 70th days. It turned out that the extract can result in a higher mean body weight gain and larger body size (P <0.05). Moreover, thyme and eucalyptus extracts appeared not to have any effect on digestibility and feed intake, but feed efficiency improved with 20 ml (P <0.05). Fecal and eye secretion index in calves receiving diets containing 15 and 20 ml of extract improved compared to the control group (P <0.05). Also, adding 20 ml of the extract reduced the amount of glucose and increased the number of red blood cells and hematocrit in the blood of the receiving calves compared to other experimental groups. The findings indicated that adding 20 ml eucalyptus and thyme extracts in daily milk, can improve the performance and health of Holstein suckling calves

In this study, the nutritional value of four camel rangeland plants, including Alhaghi Sp (AS), Haloxylon persicum (HP), Seidlitzia rosmarinous (SR)  and Tamarix Gallica (TG) in different phenological growth stages including vegetating, flowering and seeding were evaluated. Rangeland specieswere randomly sampled and their chemical composition were measured. Rumen digestibility of dry matter was assessed using a fistulated camel. The results showed that the amount of crude protein of AS and SR was higher than that of other species, Also, the lowest levels of natural detergent fibers, acid detergent fibers and tannins were observed in SR (P <0/05). Slowly degradable fraction, degradation rate and effective degradability of SR was significantly higher than other species (P <0/05). Results of this study showed that SR was better than other rangeland species due to its high crude protein content and lower acid detergent fiber and phenolic compounds, so it was used instead of alfalfa at three levels of zero, 50 and %100 in camel’s diet. Feeding SR did not affect milk yield and its components including fat, lactose and total solids. Dry matter intake of dairy camels decreased with increasing of SR in diet, but milk protein and urea nitrogen increased (P <0/05). The results of this study indicated that replacement of alfalfa hay with SR in feeding dairy camels while maintaining camel production performance, reduc the cost of feeding camel and made it more economical to rear this valuable livestock.

The effect of copper-methionine chelate and oregano essential oil in comparison to antibiotics on performance, meat quality, immune response and blood biochemical parameters were evaluated using 240 Ross 308 broilers in a 2×2×2 factorial experiment in a completely randomized design with four replicates and 10 birds per replicate. The treatments included three incremental levels (No additives, 500 mg/kg flavofospholipol antibiotics and 100 mg/kg oregano essential oil of diet) and copper-methionine chelate (0 and 118 mg/kg diet). At the end of the period (42th day), one male bird was sampled from each replicate for exploring meat quality, immune response and blood biochemical parameters. Birds fed a diet containing coppermethionine chelate with flavophospholipol showed higher live weight (P<0.05). Birds fed a diet containing copper-methionine chelates had higher weight gain and better conversion ratio (P<0.05). Also, birds fed diets without additives and antibiotics with and without copper-methionine chelates had more fatty acid oxidation than other groups (P<0.05). At 28 and 42 days of age, the highest immune response (antibody titer) was observed in the copper-methionine chelate group with oregano essential oil (P<0.05). It was shown that oregano essential oil decreased and increased LDL and HDL in the blood (P <0.05), respectively. The results of this study showed that the use of copper-methionine chelate with antibiotics improved production efficiency and the use of copper-methionine chelate and oregano essential oil supplements in poultry diets improve meat quality and increased safety.

Effect of prebiotic and extract of three medicinal plants: Chamomile, Oregano, and Marjoram on the performance, intestinal histomorphology, and blood parameters of laying hens in the late phase of production, by using 60 TETRA-SL brown-egg laying with 80-week-olds, in a completely randomizes design containing five treatments and four replicates with three birds in each experimental unit for eight weeks were investigated. Prebiotic was added at 0.5 g/kg of diet, and medicinal plant extracts in a ratio of 1:1000 were added to the drinking water of birds. Quantitative indicators at the end of each week and quality indexes at the last week of the experiment were measured. At the end of the experiment, blood was taken from one bird in each experimental unit, and the birds were slaughtered to study the intestinal bacterial population and histomorphology. The effect of experimental treatments on the quantity and quality of produced eggs was not significant (P<0.05). Blood cholesterol and yolk cholesterol were lower in the chamomile extract-receiving birds than in the other experimental groups (P<0.05). The population of E. coli and coliforms in the intestine of marjoram extract-receiving birds was lower than other treatments (P<0.05). Prebiotic treatment increased the villus height in the duodenum and ileum, and the marjoram extract increased the villus height in the ileum (P<0.05). According to the result, the use of chamomile extract can reduce the yolk cholesterol level, and the use of prebiotic and marjoram extract improves the microbial flora and intestinal histomorphology in laying hens.

The effect of different feeding methods in the first three days of the rearing period on production traits and immune system of one-day-old chicken broilers (Ross 308) for 49 days was studied. The experiment was conducted in a completely randomized design with eight treatments / four replications and 15 chickens per replication The experimental treatments included: 1- water and starter diet, 2- water and corn powder for 48 hours, 3- water containing 5% sugar and corn powder for 48 hours, 4-water containing 5% sugar and corn powder for 72 hours, 5-water containing 5% sugar and starter diet for 48 hours, 6-water containing 5% sugar and starter diet for the 72 hours, 7 water containing glucoplus and corn powder for 48 hours and 8- water containing glucoplus and starter diet for 72 hours. Treatments of 1 and 8 had the highest live weight and body weight gain at d 42 in compare to the other treatments except treatment 6 (P<0.05). The greatest daily feed intake was observed in treatment 1 which had significant difference with others groups except treatments 6 and 8 (P<0.05). The mortality rate was not significant between treatments at 42 and 49 days. The greatest production efficiency factor was observed in treatment 8 at d 42, (P<0.05), which had significant difference with others groups ( excepttreatments 1 and 5). Experimental treatments had no effect on relative weight of internal organs, carcass components and white blood cells counts. According to the results and economic considerations, initial feeding with the starter diet and common water in broiler farms is recommended.

Effect of different levels of calcium, hydroalcoholic extracts Withania coagulans, and flaxseed oil on performance, mineral retention and bone morphology using with four thousand and eighty male Ross 308 broiler chicks in a 2×3×2 factorial experiment with two calcium levels (Calcium at the recommended level and calcium 30% less than the recommended level), extract Withania coagulans (Zero, 100 and 200 mg / kg in diet) ) and flaxseed oil (0% and 2% diet) in a completely randomized design with four replications and 10 birds per treatment were evaluated for 24 days. Adding 100 mg/kg of extract Withania coagulans to the diet increased feed intake and weight gain. Mineralization of bone growth plate increased in birds fed the extract Withania coagulans supplement (P <0.05). Supplement flax oil in diet did not show a positive effect on performance and bone parameters. Physical properties and mineral retention of calcium and phosphorus were not affected by the supplements. However, the amount of bone ash was affected by the interactions of flaxseed oil and extract, and the amount of ash in chickens fed diets without extract and flaxseed oil decreased. At 24 days of age, blood phosphorus levels in chickens fed a diet containing calcium and 200 mg of extract Withania coagulans increased (P <0.05). Based on the results of this study, adding 100 and 200 ml/kg hydroalcoholic extract of Withania coagulans to the diet of calcium deficient broilers improves performance and some bone parameters.

Effect of different oil sources on growth performance, carcass characteristics and blood metabolites of broilers was studied using 160 male Ross broiler chickens in a completely randomized design with 4 treatments, 4 replicates and 10 birds each. Treatments included: 1) basal diet plus soybean oil, 2) basal diet plus sunflower oil, 3) basal diet plus canola oil and 4) basal diet plus sesame oil. Effect of different oil sources on feed intake was not significant in different periods. In grower, finisher and whole periods, sesame and canola oil fed birds showed better weight gain and feed conversion ratio compared to other oil sources. The food cost was significantly higher for diets including sesame oil compared to others and birds fed sesame oil had lower profit than canola and soybean oil fed birds (P<0.05). The relative weight of carcass, breast and thigh was higher in broiler fed with sesame and canola oil (P<0.05). The blood cholesterol decreased significantly in sesame oil treatment (P<0.05). Considering the lower price and higher profit of canola oil containing diets compared to sesame oil and also better performance of birds fed sesame and canola oil, we would recommend using canola oil in broiler diets.

This study was conducted to investigate the effects of hydro alcoholic extract of Ferulago angulata, antibiotic, probiotic, and vitamin-selenium mixture on growth performance and immune responses of broiler chickens under heat-stress conditions. A total of 350 day-old male broiler chickens (Ross 308) were used in a completely randomized design with 7 dietary treatments and 5 replicates (10 chicks/replicate). Experimental treatments were as follow: no heat stress, without any additive in the diet (negative control; NC); challenged with heat stress, without any additive in the diet (positive control; PC); PC + antibiotic; PC + probiotic; PC + vitamin and selenium mixture; and PC + 200 or 400 mg/kg of Ferulago angulata extract. The results showed that all dietary supplements decreased the negative effects of heat stress on growth performance (P<0.05). All experimental diets(except diet containing antibiotic ) increased the lymphocyte counts, but decreased hetrophil counts and heterophil: lymphocyte ratio compared with the PC group (P<0.05). Secondary total titer and IgG titer against SRBC were higher in broilers receiving dietary supplements under heat stress conditions (P<0.05). The 400 mg/kg of Ferulago angulata extract increased the cell-mediated immune response after an intradermal injection with phytohaemagglutinin-P in the toe web (P<0.05). According to the results of this experiment, the use of 400 mg/kg of Ferulago angulata extract in broiler diets improves growth performance and immune response under heat stress conditions, and can be used as a suitable alternative to antibiotics and common supplements under the heat stress conditions.

To investigate the effect of oral administration of prepared specific egg yolk antibody (IgY) against enterotoxigenic Escherichia coli K99 on growth performance, health, the prevalence of diarrhea of neonatal calves, an experiment was conducted using 60 newborn calves in a completely randomized design with two treatments. Calves were kept individually. Calves in the control group received only milk or colostrum for 30 days and calves in the treatment group received milk or colostrum with IgY against inactivated K99. During the experiment, health parameters and the prevalence of diarrhea were recorded daily, and growth performance was evaluated weekly. The results showed that average daily gain, starter dry matter intake and feed and milk efficiency were higher in the IgY group than the control group (P<0.05). The general health score in the IgY group was higher than control group and fecal and ear scores in this group were significantly lower than the control group (P<0.05). The count of fecal coliforms in the IgY group was decreased by approximately one log compared to the control group (P<0.05). The results of the present study showed that oral administration of IgY against enterotoxigenic Escherichia coli K99 has beneficial effects on health and average daily gain of suckling Holstein calves and It can be a good way to replace antibiotics.

The aim of this experiment was to compare the feedlot performance and carcass characteristics of Lori Bakhtiari and Romanov×Lori-Bakhtiari crossbreed lambs. Forty-four Lori-Bakhtiari lamb and Forty-four Romanov×Lori-Bakhtiari lambs were used in a completely randomized design and using a factorial method (2×2) during two consecutive years. The average daily gain and daily feed intake were determined by individual weaning of each animal and then feed conversion ratio was calculated. Carcass characteristics of lambs were measured. The results showed that average daily gain during fattening period (212.1vs. 179.6 g), final fattening weight (52.12 vs. 48.26 kg), feed intake, carcass weight and fat tail percentage in Lori Bakhtiari lambs were greater than Romanov× Lori Bakhtiari crossbred lambs. The average daily gain before weaning (298.4 vs. 266.8 g), the average daily gain during fattening period (217.2 vs. 161.9 g), and feed conversion ratio (7.62 vs. 9.75) in male lambs was better than female lambs (p < 0.05). Fat tail percentage and total carcass fat content in male lambs were higher than that of female lambs (p < 0.05). It is concluded that, Romanov×Lori Bakhtiari crossbred lambs had higher performance than Lori Bakhtiari lambs before weaning. However, fattening period performance and carcass weight in Bakhtiari lambs were higher compared to Romanov×Lori Bakhtiari crossbred lambs. In addition, energy spent per kg of carcass and live weights in Bakhtiari lambs was lower than Romanov×Lori Bakhtiari crossbreds. Therefore, it can be concluded that the indigenous Bakhtiari sheep breed is more useful for fattening than that of Romanov×Lori Bakhtiari crossbreds in Chaharmahal and Bakhtiari province.