Effects Of Stress And Energy Type Of Diets On Meat Quality Of Broilers

Three experiments were conducted in the present study to determine the effects of stress on energy metabolism and meat quality of broilers and the underlying mechanisms.In exp.1, broilers fed of two different type of diets of the same nutritional level were fed with corticosterone for a time to induce chronic stress ,in order to determine the effects of chronic stress and different diets on energy metabolism and meat quality of broilers.240 broilers of 0d used in this experiment were divided into 4 groups at random,as high fat diet control group, high fat diet stress group ,high carbohydrate control group, high carbohydrate stress group.each group included 3 replicates with 20 broilers each. Different diets were fed since 21d of age. and corticosterone treatment was conducted from 28 d of age. At the day of 21,28,35 and 39,birds were weighed, samples were obtained from two or three birds randomly selected from each replicate(eight or nine birds each group)for determination. The results indicated that different diets of the same nutritional level, influenced little.The performance of birds suffered from chronic stress were significantly lower(p<0.01), the content of plasma glucose,latic acid ,uric acid,the content of muscle glycogen,the ratio of liver and fat in the abdomen of the stressed birds were significantly higher(p<0.01), the pH of the muscle and the plasma T3 concentration were signicantly lower(p<0.01).In exp.2 ,broilers fed of diets of the same energy level were injected with corticosteron to induce stress , to determine the effect of short -term stress and diets on energy metabolism and meat quality of broilers . 40 broilers of46d were used in this experiment,20 fed with high fat diet,20 fed with high carbohydrate diet, blood samples were collected from the vein,then 10 birds of each group were injected with corticostrone and the left 10 corn oil,3 hours later,samlples were collected for determination . The results indicated that different diets of the same energy level did not influence the broilers'performance, energy metabolism and meat quality. Bw of birds suffered from short-term stress decreased sharply,and the loss of body weight ,the content of plasma glucose,uric acid were signicantly higher than the control group(p<0.01), drip loss of the stressed group was significantly lower than the control, and cooking loss trended to be lower.In exp.3 ,broilers fed of high fat diet,drank glucose or not ,were injected with corticosteron to induce stress ,in order to determine the effects of short -term stress and glucose on energy metabolism and meat quality of broilers. 40 broilers of 49d were used in this experiment,20 had been drinking water containing glucose,20 normal water for one week, blood samples were obtained, then 10 birds of each group were injected with corticostrone and the left 10 corn oil,3 hours later,samlples were collected again for determination. The results indicated that glucose did not influence the broilers' energy metabolism and meat quality. Body weight of birds suffered from short-term stress decreased sharply, the loss of body weight and the content of plasma glucose,uric acid were signicantly higher than the control group(p<0.01), and drip loss trend to be lower, cooking loss of the stressed group was significantly lower than the control group.All of the three experiments indicate that stress can influce energy metabolism and meat quality of broilers. The mechanisms should be further studied.