Heat stress in poultry: old problem – new approach
Heat stress is one of the most concerned issues in poultry production, especially modern poultry breeds which have high growth rate or high egg production. It is well known that heat stress has caused several negative effects on commercial poultry including behavioral responses (panting and wing lifting), physiological responses (elevation of body temperature), digestion (lower feed consumption, reduced digestive enzymes), growth rate (feed conversion ratio and body weight gain), immune system. Corticosterone, an important stress indicator in animals, is measured to evaluate heat stress in poultry in numerous studies. However, using corticosterone level is not effective enough to detect and evaluate heat stress in poultry. In recent years, by using cutting-edge techniques, scientists have approached heat stress in animals as well as poultry at a molecular level (such as heat shock protein 70, heat shock protein 90, and other new stress indicators) to better understand the mechanism and to better evaluate the severity of heat stress. In Vietnam, due to hot and humid weather, heat stress affects poultry health and production. However, there is a lack of scientific information about this stressor in commercial and colored feather chickens in Vietnam. This presentation aims to summarize information about heat stress research in poultry and addresses some approaches to alleviate its impacts on Vietnam poultry production.
DETERMINATION OF OPTIMAL METABOLISABLE ENERGY OF SUPER MEAT BROILER DUCK
Two studies were carried out to determine optimal metabolisable energy of super meat broiler duck, one study was done on duck 0-21 days with 5 ME diets: 2850, 2900, 2950, 3000 and 3050 kcal/kg feed. Another study was done on duck 22-56 days with 5 ME diets: 2900, 2950, 3000, 3050 and 3100 kcal/kg feed. Base on parameters such as: body weight, average daily gain, average daily feed intake, FCR, feed cost/weight gain, carcass rate, breast rate, thighs rate and abdominal fat rate, we concluded that optimal metabolisable energy of super meat broiler duck raising in 0-21days stage and 22-56 days stage are 2850 kcal/kg feed and 2950 kcal/kg feed, respectively.