مجله علوم دامی ایران
سال پنجاه و سوم شماره 2 (تابستان 1401)

The aim of the present study was to investigate the effect of dietary supplementation of organic selenium (oSe) on blood parameters of male broiler breeder under dexamethasone (Dexa) challange. Fifty broiler breeder roosters (Ross 308) at the age of 64 weeks were randomly allotted to five groups (10 roosters/group) and fed a standard diet supplemented with different levels of oSe during 10 successive weeks of the experimental period. To induce stress, dexamethasone (2 mg/kg body weight) was injected during weeks of 4 to 6 of the experiment, in one-day-interval manner. Experimental treatments including diet without oSe supplementation and Dexa treatments (negative control; NC), or treated with Dexa and different levels of oSe including 0 (positive control; PC), 0.15 (Se15+Dexa), 0.30 (Se30+Dexa) or 0.45 (Se45+Dexa) mg/kg of diet. During the experimental period, concentration of testosterone, corticosterone, malondialdehyde (MDA), total antioxidant capacity (TAC), hepatic enzymes activity (ALT and AST), uric acid, total protein, albumin, plasma lipid and glucose parameters, were evaluated every two weeks. Liver enzymes and glutathione peroxidase (GPX) activity, TAC, concentration of uric acid, total protein, albumin and glucose were not affected by the treatments. Dexamethasone injection increased plasma concentrations of total cholesterol, HDL, LDL and MDA in the PC group compared to the NC group (P<0.05). However, oSe ameliorated these negative impacts in dexamethasone-stressed roosters (P<0.05). Generally, the results of this study indicate that dietary inclusion of oSe mitigate the negative effects of Dexa on some blood parameters in roosters under dexamethasone challange.

the experiment was conducted to investigate the effect of using different fat sources in the starter diet on the growth and health parameters of early weaned Ghezel lambs. 20 female lambs of Ghezel sheep breed after birth and 4 weeks of breastfeeding was randomly divided into 4 groups of 5 heads (4 treatments with 5 replicates) so that the average weight at the beginning of the period was the same for the groups. After two weeks of habituation period, they were fed using a combination of 90:10 concertrate: forage as starter diet for 2 months. The experimental diet in the experimental groups included 3% calcium salt of unsaturated fatty acids from flaxseed oil, soybean oil and fish oil as fat sources. The control group fed only breast milk during the exprimental period. The effect of treatments on dry matter consumption and weight gain is significant. The highest amount of feed and weight gain was observed in the treatment of 3% calcium salt of flaxseed oil. The effect of the treatments on the biometric characteristics of the periods was significant. The highest amount of insoluble fiber digestibility was observed in neutral and acidic detergents, crude protein, and organic matter in the treatment of 3% calcium was salt of flaxseed oil. The digestibility of raw fatty acid did not show a significant difference between the treatments. The volatile fatty acids and ruminal pH did not show a significant difference between the treatments. The highest number of prostheses was observed in the treatment of 3% flaxseed oil. Total blood protein levels showed a significant decrease in fish oil treatment compared to control. Cholesterol and blood glucose levels decreased significantly in all treatments compared to those fed with breast milk, but triglyceride and albumin levels did not differ significantly compare to control group. In general, the experimental results showed that early weaning improves the growth of lambs and because the best performance was observed in the treated feed with 3% flaxseed calcium oil, so using the level of 3% of this oil in starter diet of early weaned lambs might be recommended.

This study aimed to isolate lactic acid bacteria from gastrointestinal tract of honey bees (Apis mellifera) and assess the probiotic potential of isolates, and their effect on some performance parameters of colonies. Thus, 10 colonies out of an apiary with one hundred bee colonies were randomly selected and used for sampling. Twenty worker bees were sampled from each hive and after being transferred to the laboratory under complete comfort and ventilation conditions, their gastrointestinal tract was completely isolated under carbon dioxide flushing, and after culture in MRS medium different microbial colonies were selected. Liquid-solid periodic cultures were repeated up to 8 steps to achieve pure cultures. Finally, gram-positive, catalase and hemolysis negative samples were isolated and identified based on phylogenetic analysis. The results of identification of the isolated bacteria using 16s rRNA sequences showed that G1 isolate (MA4 strain) was 99% similar to Pediococcus acidilactica, the G2 isolate could not be sequenced due to technical problems in sending samples abroad and isolate G3 (strain MA5) was 99% similar to lactic acid pediococcus strain 8185. Finally, the strain MA14 isolated from the bee's gastrointestinal tract during the summer under anaerobic conditions was 97% similar to the HM75-1 strain Pediacocus pentosus, which was named G4. These bacteria were registered in the Gene bank (NCBI) with accession number of MW376601, MW376904, MW376896 and MW405566, respectively. In vivo studies showed the positive effects of treatment with isolates by spraying on frames and bacterial culture mixed in syrup (sugar-water) on spawning, production and hygienic behavior of bees. Comparison of treatments with Duncan's multiple range test (p≤ 5%) showed that all experimental treatments in quantitative population factors and spawning and quality were significantly different from the control treatment. However, the control treatment had a significant difference in honey reserves due to low spawning compared to experimental treatments and less nectar consumption.

To investigate the effect of different levels of Algasan pigment on the performance and meat quality of Ja[amease quail, 204 bird at day three of age, were randomly divided into four groups in three replications. Treatments included control diet (without pigment) or with 0.1, 0.2, and 0.3% (A1, A2, and A3) Algasan, respectively. In addition to recording performance data, at day 38 of age, two male quail were randomly selected from each exprimental unit to evaluate meat quality. Data were analyzed by SAS software and means were compared by Duncan test. The effect of different levels of pigment in quail diets on mean body weight gain, feed intake, feed conversion ratio, and live weight were not significant. But the highest carcass weight was observed in A1 treatment (118.33 g), the highest carcass yield in A3 treatment (73.36%), the highest light density in A1 treatment (2.029, 1.268, and 2.249%), and the highest water holding capacity in A3 treatment (4.720) (P≤0.05). The lowest meat pH, drip loss, and cooking loss showed in control (6.342), A2 (13.055%), and A3 (19.985%) treatments, respectively (P≤0.05). In general, Algasan pigment might be effective in improving some parameters of the performance and quality of quail meat.

The aim of this study was to investigate the effect of genotype by environment interaction through calculating the rank correlation between estimated breeding values of bulls in Iran and in Interbull. The data of 2,000,378 records of 305 days of milk, fat and protein production in the first, second and third lactations in years of 2004 to 2021 were used. The records were from daughters of 9603 sires in 3,444 herds. In model one, the breeding values of animals in the multivariate analysis for milk, fat and protein production of first lactation were estimated. In model two, a repeatability model was used to estimate breeding values in the multivariate analysis for milk, fat and protein production from first to third parity. Rank correlation were estimated between Iran and Interbull for bulls which had at least 20 daughters in 10 herds. In the single-parity model, the rank correlations between the estimated breeding values in Iran and Interbull for milk, fat and protein were 0.76, 0.75 and 0.76, respectively. In the multiple-parity model, the rank correlations between the estimated breeding values in Iran and Interbull for milk, fat and protein production were 0.48, 0.43 and 0.51, respectively, which shows the interaction of genotype by environment. The results showed different rank correlations for two types of models used. Therefore, due to genotype by environment interaction, the rank of bulls in Iran could be different from Interbull estimates.

For this expriment 1440 Ross 308 male broilers (from 1 to 42 days of age) were used in a randomized complete block design with eight treatments in six blocks. Experimental diets included: soybean meal (control treatment), raw soybeans, full-fat soybeans extruded (15%) at 90 and 150°C, and each of them with 0.02% or without (0.0) protease enzyme supplementation. The use of raw soybean compared to soybean meal or extruded full-fat soybean significantly reduced feed intake, body weight and relative carcass weight, as well as increased feed conversion ratio and pancreatic weight (P<0.01). weight gain was improved in diets supplemented by protease enzyme compared to diets containing raw soybean (P<0.01). Feed conversion ratio was improved in diets containing raw soybean and soy bean meal by dietary protease supplementation (P<0.01). Extrusion temperature did not affect the growth performance of experimental birds. Diet containing raw soybean without enzyme increased blood cholesterol levels (P <0.05). According to the findings of this study, the use of protease enzyme in diets containing soybean meal or raw soybean can improve the performance of broilers However, such effect is less pronounced in diets containing extruded full-fat soybean meal.