The effect of grape seed extract and vitamin C feed supplementation on some blood parameters and HSP70 gene expression of broiler chickens suffering from chronic heat stress

In this experiment, the effect of hydroalcoholic grape seed extract (GSE) and vitamin C feed supplementation on some blood parameters and heat shock protein 70 (<em>HSP70</em> gene) expression of broiler chickens suffering from chronic heat stress was investigated. Experimental diets included control diet (with no additive), 3 levels of GSE (150, 300, 450 mg/kg), and one level of vitamin C (300 mg/kg). Each diet was fed to 5 replicates of 12 male chicks each, from d 1 to 42. The birds suffered from chronic daily heat stress under 34±1°C temperature with 65 to 70% relative humidity for 5 h from 29 to 42 d of age. Results showed that 300 mg/kg GSE supplementation increased body weight of broilers both before and after heat stress condition (at 28 and 42 d, respectively). Also, birds fed 300 mg GSE/kg diet had higher European production efficiency factor during the whole period of the experiment. Supplementation of GSE decreased the concentration of serum glucose at 28 and 42 d; at 42 d (during heat stress condition) and at 450 mg/kg diet it decreased cholesterol, triglyceride, lowand very low density lipoprotein concentration of serum blood. Vitamin C supplementation decreased serum cholesterol concentration of broilers suffering from heat stress. <em>HSP70</em> gene expression in heart and liver of broilers reduced by GSE and vitamin C supplementation pre- and during chronic heat stress condition.

Manipulation of broiler chickens sex differentiation by in ovo injection of aromatase inhibitors, and garlic and tomato extracts

The influence of in ovo administration of aromatase inhibitors, clomiphen citrate, tomoxifen, and garlic and tomato extracts on sex differentiation in broiler chickens were investigated in 2 experiments. Five hundred, and 1,000 fertile eggs from Ross 308 strain were used in experiments 1 and 2, respectively. In both experiments, eggs were divided into 5 groups: control group (DW, 0.1 mL/egg), tomoxifen (0.05 mg/egg), clomiphene citrate (0.05 mg/egg), garlic and tomato extracts (0.1 mL/egg). Eggs were sanitized and prepared for incubation in a regular automatic hatchery. Experimental preparations were injected into eggs at day 5 of the incubation period. Injection sites on the eggs were cleaned with 70% ethylic alcohol, bored by a needle, and aromatase inhibitors were injected into the white from the thin end of the eggs by insulin syringe and then sealed by melted paraffin. In experiment 1, hatched one-day-old chicks (mixed-sex) were raised till 42 days of age in 25 floor pens with a completely randomized design. Experiment 2 was designed to investigate the effects of sex and treatments on the feed-to-gain ratio of broiler chicks. In experiment 2, hatched one-day-old chicks were feather sexed and raised till 42 days of age in 50 floor pens. A completely randomized design with a 2 × 5 factorial arrangement of treatments (sex×treatment) was used. Gonads of the chicks were checked to determine their sex on day 42 by optic microscope to make sure feather sexing was correct. At the end of both experiments, on day 42, one bird from each pen was slaughtered for carcass analysis. In experiment 1, hatchability and the one-day-old weight of chicks showed no significant differences among treatments (P > 0.05). However, in ovo administration of garlic and tomato extracts caused the highest percentage of male chicks (P < 0.05). Also, the percentage of thighs and wings of the males were significantly higher than those of females (P < 0.05). In experiment 2, feed-to-gain ratio of male and female broiler chicks showed no significant differences among treatments (P > 0.05).

Effects of Zinc, Manganese, and Taurine on Egg Shell Microstructure in Commercial Laying Hens After Peak Production

Much strive has been made to improve egg shell quality in laying hens. This study was conducted to evaluate the effects of two microminerals, zinc and manganese, besides taurine semi-essential amino acid on eggshell quality after peak production of Hy-line laying hens. A total of 720 laying hens were assigned to 18 treatments in a completely randomized design (3 × 3 × 2 factorial) at week 71. Experimental period included 8-week adaptation and using 18 dietary treatments for about 6 weeks. Dietary treatments included Zn (0, 80, and 160 mg/kg), Mn (0, 90, and 180 mg/kg), and taurine (0 and 1960 mg/kg). Supplementation of 90 mg Mn and 1960 mg taurine in laying hens' diet after peak of production improved egg shell quality without any negative effect on the internal quality of the egg. Egg specific gravity significantly increased in response to Zn, Mn, and taurine in comparison with control treatment (P < 0.05). Applying 1960 mg taurine/kg diet significantly improved calcite crystal's structure and eggshell strength in comparison with control treatment (P < 0.05). It was concluded that adding Mn and taurine can positively affect eggshell quality of laying hens post peak period.