This study was carried out to determine the effects of dried grape pomace supplementation in a corn-soy-based diet on performance, egg quality, plasma and egg lipid peroxidation, and some biochemical parameters of laying hens. In this study, 96 moulted 80-week-old Bovans laying hens were distributed into three groups with eight replicates. The hens were fed a supplemented diet with 0% (control group), 4% and 6% grape pomace (experimental groups) for 12 weeks. In the study, the effects of grape pomace supplementation in a corn-soy-based diet on performance, internal and external egg quality, serum total cholesterol, total protein, glucose and triglyceride levels, and plasma and egg yolk malondialdehyde (MDA) levels were determined. The addition of grape pomace to laying hen diet did not significantly affect live weight, feed intake, egg production and feed efficiency (P > 0.05). In all treatment groups, supplementation did not significantly affect albumen index, Haugh unit, egg yolk index, yolk colour, eggshell ratio, eggshell thickness, egg-specific gravity, total cholesterol, total protein and triglyceride compared to the control group (P > 0.05). In the study, 4% grape pomace supplementation to diet significantly increased egg weight (P < 0.001), and both 4% and 6% grape pomace supplementation levels significantly increased liver weight (P < 0.05) and liver weight ratio (P < 0.01). Grape pomace addition to laying hens diet significantly decreased plasma MDA and serum glucose levels (P < 0.001). Also, grape pomace addition significantly decreased egg yolk MDA levels on day 1 (incubation on 0 minute; P < 0.001), and day 15 [incubation on 0, 30, 60 and 90 (P < 0.05) minutes]. The results of this study concluded that performance, egg quality and serum total cholesterol, total protein and triglyceride levels were not negatively affected. Plasma and egg yolk MDA, and serum glucose levels were reduced by 4% and 6% supplementation to laying hen diets. It was concluded that grape pomace supplementation has the potential to extend shelf life.

The aim of this study was to investigate the effect of dietary supplementation of green tea (Camellia sinensis) catechins in quail (Coturnix coturnix japonica). Quail were fed with a basal diet, and the treatment groups were fed on the basal diet with 1.25 or 2.50 g/kg catechin supplementation for 30 d. Fattening performance and meat quality of the quail were estimated. Serum total antioxidant status (TAS), plasma and liver malondialdehyde (MDA) and some serum biochemical parameters were measured. The results showed that catechin supplementation did not affect live weight, feed intake, feed conversion ratio, carcass weight, carcass dressing or the nutrient composition of breast and thigh meats. The water holding capacity (WHC) of breast meat was increased in the 2.50 g/kg catechin treatment. Catechin supplementation increased the serum TAS, but decreased plasma MDA and liver MDA concentration as well as serum glucose and total cholesterol levels. Serum triglyceride and total protein levels were not affected by catechin supplementation. In conclusion, catechins have effective antioxidant hypoglycaemic and hypocholesterolaemic properties, as well as having the potential to increase meat quality in fattening quail. On the other hand, catechin supplementation did not have any negative effect on the fattening performance, meat nutrient composition and fattening costs in fattening quail.

The aim of this study was to investigate the effect of green tea (Camellia sinensis) catechin addition to breeder quail (Coturnix coturnix japonica) diet on productivity, reproductive performance, egg quality and yolk malondialdehyde (MDA) levels during storage, and some serum biochemical parameters. In this study, a total number of 180 quail, 7 weeks of age were randomly divided into 3 groups (1 control group and 2 treatment groups) with 5 replicates (9 females + 3 males). The control group was fed basal diet; the treatment groups were fed basal diet with 0.2% and 0.4% catechin supplementation for 5 weeks. The results of this study showed that 0.2% and 0.4% catechin addition had no significant effects on live weight, feed intake, egg production, feed efficiency, and egg internal quality (yolk colour, albumen index, yolk index, Haugh units, and pH) (P > .05). Catechin addition reduced egg weight, egg specific gravity, and egg shell thickness (P < .001). The catechin addition to diet significantly diminished MDA concentrations of eggs (P < .05). Serum glucose and triglyceride levels significantly decreased (P < .05) in the 0.4% catechin group, but were not significantly affected (P > .05) in the 0.2% catechin group compared to the control group. The addition of 0.2% catechin significantly increased fertility (P < .05), hatchability (P < .01), and the hatchability of fertile eggs (P < .05). In conclusion, catechin supplementation to breeder quail diet has the potential to increase egg shelf-life and reproductive performance. On the other hand, supplementation with these catechin levels decreased egg weight and egg shell quality. ARTICLE HISTORY

This experiment was conducted to evaluate the effects of supplementary thyme (Thymus vulgaris) essential oil (TEO) and A, C, and E vitamins on performance, egg quality and some biochemical parameters of laying hens under heat stress (HS). A total of 120 White Leghorn laying hens were randomly distributed into 5 experimental groups with 6 replicates and each replicate had 4 laying hens. The HS group was housed at 34°C between 08:00 am and 05:00 pm and the rest of the day at 22°C. The experimental groups were; 1: HS group; 2: HS + TEO (300 mg/kg TEO in diet), 3: HS + TEO + Vit-C (300 mg/kg TEO + 250 mg/kg vitamin C in diet), 4: HS + TEO + Vit-E (300 mg/kg TEO + 250 mg/kg vitamin E in diet), and 5: HS + TEO + Vit-A (300 mg/kg TEO + 15,000 IU/kg vit-A in diet). In the study, body weight, egg weight, feed intake and egg quality of the hens were not affected with treatment groups. Serum glucose level was decreased in the TEO group, plasma MDA was decreased in the TEO and TEO + Vit-C groups and 8-OHdG was decreased in the TEO + Vit-E. It was concluded that it would be more beneficial to use TEO against HS in laying hens with Vit-E and Vit-C instead of using it alone.

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