The present experiments were undertaken to investigate the effects of environmental temperatures on growth, abdominal fat content, rate of muscle protein turnover, and heat production in tube-fed intact male broiler chickens. Plasma concentrations of thyroxine (Td), triiodothyronine (Ts), and corticosterone (CTC) were also examined. Chicks (15d old) were kept at different environmental tempera- (16,19,22,25,28,31, and 34") and given the experimental diet (200g crude proteid kg, 1337MJkg metabolizable energy) by tube three times daily throughout the 12d experimental period. In the hot conditions, except for 34", body-weight gain was significantly higher than in the cold conditions. Thus, food conversion ratios (food : gain ratios) were lower when the birds were exposed to the hot conditions other than 34". Likewise, abdominal fat content was significantly increased, and heat production was lower in the groups kept under the hot conditions other than 34". The rate of skeletal muscle protein turnover and plasma concentration of CTC were decreased when the birds were exposed to hot conditions other than 34", suggesting a role of CTC in the regulation of muscle protein turnover. Plasma coneenfrations of Tg and T j were significantly decreased as environmental temperature increased. These results clearly show that plasma concentrations of thyroid hormones and CTC are associated with accelerated muscle protein turnover and heat production.Environmental temperature: Muscle protein turnover: Heat production: Thyroid hormones: Corticosterone

1. The effects of dietary polyphenols (PP) on growth and oxidative stress in the corticosterone (CTC) treated broiler chickens model were studied. 2. Chicks (Cobb strain) were divided into 3 (CTC) x 3 (PP) blocks and given diets containing CTC at concentrations of 0, 10 and 20 mg/kg. 3. The body weight gain was lower when the birds were treated with CTC. However, the high dose of PP tended to reduce the effect of CTC. 4. The abdominal fat content, plasma triglyceride concentration and liver weight were increased by CTC and reduced by PP. 5. Muscle and liver thiobarbituric acid reactive substance (TBARS) were elevated by CTC and these effects were reduced by PP. Plasma CTC concentration was increased by dietary CTC treatment and decreased by PP. 6. In conclusion, our results indicate that PP can minimise growth inhibition, hyperlipidemia and oxidative stress induced by CTC treatment in broiler chickens.

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The present study was conducted to show that dietary supplementation with a fungus, Aspergillus awamori, modifies muscle fatty acid profiles in broiler chickens. A total of thirty chicks, selected from a group of 100 chicks aged 15 d, were divided into a control group and two treatment groups (ten birds per treatment). The control group was fed a basal diet, and the treatment groups were fed basal diets supplemented with A. awamori at levels of 0·05 and 0·2 %. From the start of the study at 15 d, the birds were raised for an additional 12 d, and growth and the muscle fatty acid profile were evaluated. Although feed intake was decreased by the fungus, body-weight gain and breast muscle weight were increased, and thus, feed efficiency was improved. Abdominal fat and plasma cholesterol and TAG were decreased, while plasma HDL-cholesterol and breast muscle fat content were increased. Interestingly, muscle a-tocopherol content was increased and muscle thiobarbituric acid-reactive substances were decreased by A. awamori. Furthermore, there was an observed decrease in SFA and an increase in unsaturated fatty acids in the muscle fat due to the fungus feeding. The mRNA of fatty acid synthase, acetyl-CoA carboxylase and D-6 desaturase in the muscle were all increased, while the mRNA of 3-hydroxyl-3-methylglutaryl-CoA reductase and carnitine palmitoyl transferase 1A were decreased by the fungus. In conclusion, the present study clearly shows that the muscle lipid profile could be modified by the addition of A. awamori to the diet.

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