فصلنامه تحقیقات تولیدات دامی
سال نهم شماره 3 (پاییز 1399)

This study was conducted to determine the effect of different levels of omega-3 and omega-6 calcium fat powders on performance, hatchability, serum lipids, abdominal fat, and ovarian follicle count in Ross-308 broiler breeder hens (65 week-old). The experiment was performed in a repeated measurement design with 84 hens and 28 roosters with seven treatments (four replicates) during three months. The experimental groups included control group (no fat powder), 1.5 and 3% of animal omega-3 calcium fat powder of fish oil origin (ω3F), plant omega-3 calcium fat powder of linseed oil origin (ω3L), and omega-6 calcium fat powder of soybean oil origin (ω6S). The results showed that the highest average of HDEP was belonged to the experimental groups containing 1.5% ω3F (61.98), and ω3L (60.25) without significant difference with together (P> 0.05). However, among experimental groups, the highest egg mass (44.78 g/h/d) was obtained from consumption of 1.5% ω3F (P<0.05). The highest concentrations of triglycerides (1806.8 mg/dL), cholesterol (206.25 mg/dL), and low density lipoprotein (244/25 mg/dL) of serum were belonged to control group that was significantly different from other experimental groups (P<0.05). The percentage of hatchability of fertile eggs was improved by consuming diets containing fat powder, except 3% ω6S, when compared to control (P<0.05). Overall, considering the production performance, hatchability and economic explanation of diets, it seems that addition of omega-3 calcium fat powder at the level of 1.5% (ω3F and ω3L) is affordable and can have a positive effect on old broiler breeder hens.

This study was conducted to evaluate the effect of spearmint and eucalyptus essential oils on growth performance, carcass traits and immune system performance of broiler chickens under heat stress conditions. Two hundred and fifty one day-old broilers (Ross- 308) were randomly divided into five treatments in five replicates with 10 birds per replicate from 1 to 42 days of age, in a completely randomized design. Treatments included: 1. Negative control (under normal temperature conditions), 2. Positive control (under heat stress conditions), 3. Positive control+0.5 mL spearmint essential oil per liter of drinking water, 4. Positive control+0.5 mL eucalyptus essential oil per liter of drinking water, and 5. Positive control+0.5 mL spearmint essential oil+0.5 mL eucalyptus essential oil per liter of drinking water. Heat stress was applied in the grower period (26-42) at 32 ± 1 °C (9 am to 5 pm). The results showed that in the grower period and the entire trial period, heat stress reduced feed intake (P<0.05). Thermal stress increased the relative weight gain of the entire intestine and decreased the relative weight loss of the thighs (P<0.05), also reduced the lymphocyte proliferation and survival (P<0.05), and decreased the intensity of peripheral blood phagocytic respiration (P<0.01). However, the use of eucalyptus essential oil and a mixture of two essential oils (eucalyptus+ spearmint) improved the lymphocyte propagation and compensated for the reduction of heat stress (P<0.05). In addition, the combined use of spearmint and eucalyptus essential oil improved the intensity of respiratory explosion in macrophages compared with negative and positive control treatments (P<0.01). In general, the use of essential oils improved immune function but did not affect the performance of broiler chicks.

This study was conducted to evaluate the effects of particle size of chromium-methionine (Cr-Met) on growth performance, carcass traits and meat quality of broiler chicks under physiological stress conditions. A total of 288 broiler chicks (male) were used in a 2 × 3 factorial arrangment with two stress status (no stress, stress) and three levels of Cr-Met (no Additive, 2000 ppb of Cr-Met, and 2000 ppb of Cr-Met milled) in a completely randomized design with six treatments, four replicates and 12 birds per each pen. Dexamethasone was added to diets (1.5 mg/kg diet) for a week (18-24 d) to induce physiological stress. Feed intake and body weight were measured weekly and feed conversion ratio was calculated. The malondialdehyde content and the water holding capacity of meat were measured at 24 and 46 d of age. Also, breast meat pH was measured at 46 d. Physiological stress decreased feed intake, weight gain, carcass yeild, relative weight of spleen, bursa, heart and liver, but increased FCR and water holding capacity of meat bereast (P<0.05). In stressed birds, both forms of dietary Cr- Met improved FCR and increased the meat pH (P<0.05). There were no differences between the effects of particle size of Cr-Met on the studied parameters. According to the results of this experiment, dietary supplementation of 2000 ppb Cr-Met in different sizes reduced the negative effects of physiological stress and improved the FCR and carcass yield of birds under physiological stress.

The aim of the present study was to conduct a genome wide association studies (GWAS) based on gene set enrichment analysis for identifying the loci associated with body weight in four chicken breeds including Chahua, Silkie, Langshan, and Beard using the high throughput single nucleotide polymorphisms (SNPs). Phenotypic and genotypic data were obtained from the Frontiersin online public repository. In this study, the 402 cocks and hens were used with body weight from 1 to 15 weeks using GenABEL software. The gene enrichment analysis was performed with the goseq R package. In the next step, a bioinformatics analysis was implemented to identify the biological pathways performed in GO, KEEG, DAVID and PANTHER databases. Ten SNP markers on  chromosomes 1, 2, 5, 7, 10, 14, 18, 19, 20 and 27 located in ABCG1, MYOD1, MYH10, MYH11, MYO1B, MYO1C, MYO1E, MYL1, MYL2, MYL3, SLC2A8, ACACA, ACOX1, ACOX2, and PNPLA2 genes were identified. Some of the genes were found are consistent with some previous studies and to be involved in biological pathways related to body weight. According to pathway analysis, 17 pathways from gene ontology and KEGG pathway were associated with the body weight (P˂0.01). Among those pathways, the cytoskeletal protein binding, anatomical structure development and tricarboxylic acid cycle had significant association with skeletal muscle fiber and metabolism lipid traits. In total, this study supported previous results from GWAS of body weight; also revealed additional regions in the chicken genome associated with these economically important traits. The use of these findings can accelerate the genetic progress in the breeding programs.

The current experiment was conducted to investigate the effect of conocarpuson digestibility, microbial rumen fermentation, and blood parameters in the Arabi sheep. At the first experiment, the most proper diet among diets containing 0, 5, 10, 15 and 20% conocarpusfoliage, instead of corn silage, were selected by in vitro methods. The result indicated, diet containing 15% conocarpus had the greatest potential of gas production and digestibility of dry matter and neutral detergent fiber (p < /em><0.05). Then, diet containing 15% conocarpusfoliage was used in the feeding of Arabi sheep with average weight of 25±5 kg and 12±1 months age. These diets containing 55% forage to 45% concentrate were used in the completely randomized design for a period of 35 days. Digestibility of dry matter, crude protein, organic matter and neutral detergent fiber and acid in the experimental diets was not different (p < /em>>0.05). Also, blood triglyceride and aspartate and alanine aminotransferase did not influence by treatments (p < /em>>0.05). The potential of gas production and digestibility of straw in sheep fed with control and experimental diets had not significant difference (p < /em>>0.05). Dry matter intake, blood urea, glucose and LDL in treatment containing conocarpus were less than the control treatment, but blood cholesterol and HDL increased (p < /em><0.05). Ammonia nitrogen and pH of rumen in diet containing conocarpus was less than control (p < /em><0.05). The result of this study showed, due to the lack of a negative effect on digestibility and fermentation and the other parameters in this experiment, maybe conocarpus foliage can be used by 15% as replacement with some forage in Arabi sheep diet.

This experiment was aimed to study the effect of Ferula assa foetida essential oil or Artemisia aucheri essential oil in diets containing different concentrate ratios (40 and 60% of DM) on in vitro fermentation kinetic and acidosis induction. Essential oils were added at 0.05% of diet DM. Gas production parameters, pH, N-ammonia and volatile fatty acids (VFA) concentrations and total protozoa population were measured and organic matter digestibility (OMD) was estimated. The effect of Ferula assa foetida and Artemisia aucheriessential oils on prevention of in vitro acidosis induction was measured. The results showed that the interaction of diets and essential oils had no significant effect on in vitro gas production parameters, N-ammonia concentration, pH, total VFA, acetate, propionate and valerate concentrations, total protozoa population, Entodinium, Diplodinium,and Ophryoscolex population. The interaction of diets and essential oils on estimated OMD was significant (92.64 vs. 83.1 %, p < /em><0.05), and diet containing low concentrate level without essential oils had the lowest estimated OMD. Essential oils reduced gas production, total protozoa population and N-ammonia concentration (p < /em><0.05). Results of Ferula and Artemisia essential oils on prevention of in vitro acidosis induction showed that both essential oils prevent acidosis induction. It was concluded that Ferula and Artemisia essential oils improved rumen fermentation.

This study was conducted to evaluate the effect of different levels of cinnamon essential oil (CEO; 0, 60 or 120 mg/kg) on chemical composition, aerobic stability and gas production parameters of alfalfa silage on in vitro condition. Experimental treatments included: alfalfa without additive (control), alfalfa with 60 mg cinnamon essential oil/kg (CEO60), and alfalfa with 120 mg cinnamon essential oil/kg (CEO120). Silos were kept at room temperature for 60 days. After opening the silos, the chemical composition of the treatments and aerobic stability of the silages were measured. Gas production was measured by in vitro method with five replications at 2, 4, 6, 8, 12, 16, 24, 36, 48, 72, 96, and 120 hours. The data were analyzed in a completely randomized design. The results showed that adding the essential oil to alfalfa silage significantly reduced the pH of the silage in comparison to control (P<0.05). Adding CEO to alfalfa silage at 60 mg increased water soluble carbohydrate concentration (4.80%; P<0.05) in comparison to control (4.08%). Crude protein content increased in treatments supplemented with CEO (12.47%) in comparison to control. Aerobic stability was increased in CEO treated groups compared to control. Adding 60 mg/kg of CEO reduced the gas production volume compared to control treatment (P<0.05). Overall, the obtained data indicated a positive effect of cinnamon essential oil on the quality of alfalfa silage and its fermentation properties.

Doogh is one of the traditional drinks in Iran and yeast is the original reason of its spoilage. In this research, propolis (a product of bee) was used for preventing the yeast growth in unpasteurized doogh. The polymerase chain reaction (PCR) method was used to diagnose the yeast that caused spoilage (Kluyveromyces marxianus). Water, glycerol and ethanol were used as solvents to extract phenolic compounds of propolis. According to extraction efficiency, capability of usage in food products and results of MIC and MBC tests, glycerol extract has been selected for Doogh examinations. The effect of 1.5, 3, 4.5, 6% of glycerol extract on pH, titratable acidity, DPPH, decreased yeast count and sensory properties of unpasteurized Doogh during storage at temperatures of 5 and 25°C. Results revealed that 3% glycerol extract of propolis, decreased yeast during storage at both temperatures of 5 and 25 °C without any negative effect on sensory parameters, for two and more than fourteen days, respectively. Also, total yeasts significantly decreased with increasing the glycerol extract of propolis (P<0.05). Furthermore, the DPPH was not affected during storage at both temperatures. Using the propolis extract in unpasteurized Doogh resulted in the prevention of yeast caused spoilage and specially production of a functional food containing high amounts of antioxidants.