Effects Of Cysteamine On Performance And Carcass Characteristic In Broiler Chickens Under Different Growth Patterns

Three experiments were conducted to investigate the effects of cysteamine on the performance and carcass characteristic in broiler chickens under different growth patterns.Experiment 1: Effects of cysteamine on the performance, enzyme activity in digesta, viscera growth in broiler chickensA single factorial experiment was designed with four levels of cyteamine. The levels of the cysteamine were 0, 30,100,200 mg/kg in diets for 22-42 days old broilers. The results showed that 100 mg/kg cysteamine significantly improved the body weight compared with the control group; The 30 and 100 mg/kg groups increased the enzyme activity of the chymotrypsin in the 42-day-old broilers; The high level 200mg/kg of cysteamine damaged the liver, spleen, stomach and jejunum growth. Experiment 2: Effects of cysteamine and different levels of lysine on the compensatory growth of broiler chickensAn experiment was conducted to investigate the effects of cysteamine and dietary levels of lysine on the compensatory growth of broiler chickens. From 8 to 21 day, the broilers were fed low-energy or low-protein diets. The levels of cysteamine were 0, 100 mg/kg and the levels of lysine were 1.0%, 1.1%, 1.2% from 22 to 42 day of age. The growth performance, carcass characteristic and intestine growth were analyzed. The results showed that cysteamine significantly improved body weight and carcass ratio. The 1.1% lysine improved the feed conversation and trended to increase the weight and length of the intestine.Experiment3: Effects of different levels of nutrition in the first week on the compensatory growth of broiler chickensThe levels of protein and energy in the first week diets were 23%, 13.57MJ/Kg and 21%, 12.39MJ/Kg. From 8 to 21 day, the broilers were fed low-energy or low-protein diets. Cysteamine was added to the diet during 22 to 42 day. The experiment was carried out to investigate the effects of different levels of nutrition in the first week on the compensatory growth. The results showed that the nutrient intensity of diet in first-week had a significant effect on the body weight in 7 day, but had no effects on the final body weight. The cysteamine improved the body weight in 42-day-old. The diet with high nutrient intensity in first-week significantly increased the abdominal fat rate under the protein restriction and trended to increase the intestinal weight and length in 42 day.