Hakan Bayraktar

Effect of heat stress on oxidative stress, lipid peroxidation and some stress parameters in broilers

1. This study was conducted to determine the effects of heat stress on fearfulness, leucocyte components, oxidative stress and lipid peroxidation in two commercial broiler strains, Cobb (C) and Ross (R). 2. At 36 and 37 d of age birds were exposed to 38 ± 1°C for 3 h. Rectal temperatures, duration of tonic immobility (TI), haematocrit values, proportions of leucocyte components (heterophil, lymphocyte, basophil, eosinophil, monocyte), malondialdehyde (MDA) concentrations and antioxidant enzyme activities (CAT, SOD, GPx) of all the birds were determined, before and after heat treatment. 3. Rectal temperatures increased and haematocrit values decreased in birds exposed to heat stress. Heat stress caused a significant increase in heterophil/lymphocyte and in basophil ratios. 4. Exposing birds to heat stress increased duration of TI, suggesting heat-stressed birds tended to be more fearful. 5. Heat stress resulted in a significant Genotype × Treatment interaction for MDA concentration. CAT, SOD and GPx activities; MDA concentrations in heat-stressed R strain birds were greater than in heat-stressed C strain birds.

The effects of moderately oxidised dietary oil with or without vitamin E supplementation on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence of male broilers

BACKGROUND The experiment was conducted to determine the effects of dietary supplementation of oxidised oil with or without vitamin E on performance, nutrient digestibility, some blood traits, lipid peroxidation and antioxidant defence system of male broilers. RESULTS The supplementation of oxidised oil with or without vitamin E to the grower diets did not significantly affect performance, the pH and viscosity values of excreta and nutrient digestibilities in male broilers. Oxidised oil supplementation slightly increased plasma triglyceride and cholesterol concentrations but did not alter plasma glucose concentration. Although malondialdehyde (MDA) and nitric oxide concentrations tended to be higher in the oxidised oil group, these increases were not significant. Birds fed the diet containing oxidised oil had significantly lower superoxide dismutase (SOD) activity. However, no differences were observed in glutathione peroxidase (GSH-Px) activity and uric acid concentrations of broilers fed oxidised oil as compared to the control group. Dietary vitamin E supplementation decreased MDA concentration whereas increasing SOD activity, suggesting that vitamin E supplementation reduced susceptibility to lipid peroxidation. CONCLUSION The results showed that a milder oxidative stress occurred by supplementation of moderately oxidised oil to the diet of broilers and vitamin E supplementation had been helpful in alleviating lipid peroxidation.

Effect of Honey Treatment on Some Quality Characteristics of Broiler Breast Meat

Abstract Yücel, B., Önenç, A., Bayraktar, H., Açikgöz, Z. and Altan, Ö. 2005. Effect of honey treatment on some quality characteristics of broiler breast meat. J. Appl. Anim. Res., 28: 53–56. Breast meats of 12 broilers (Ross-308) were used to determine the effect of marination with honey water mixture (0, 20, 30% v/v) on their meat quality and bacterial activity. Treated meats were preserved at 4C for 7 days in vacuume. Drip loss, pH level and marinate uptake did not change significantly in breast meats marinated with different levels of honey and without honey. Marination with honey did not significantly affect the L*(brightness) and a*(redness) values of breast meats on 1st and 7th days of treatment. However, b* (yellowness) values were significantly affected by honey treatment. After 7th day, no significant differences were obtained for tenderness, flavor and acceptability between treatment and the control groups. Breast meats marinated with honey showed a slight decrease in bacterial number compared to control group after 4th day. It is indicated that honey marination might be considered as a means of limiting bacterial growth in broiler meat without any adverse effect on meat quality and sensory characteristics.