Effects Of Diets Composed Of Different Starch Sources On Growth Performance, Digestive Physiology And Glucose Metabolism In Broiler Chickens

0-4week-old Arbor Acres broiler chickens were selected to investigate influences of dietscomposed of different starch sources (corn, wheat, rice) on growth performance and themechanisms of starch digestion and glucose absorption of broiler chickens by feeding test,comparative slaughter test, and metabolic test. The effect of diets composed of different starchsources were elucidated from both digestion and absorption of digestive tract and metabolism ofliver tissue.Trail1. Effects of diets composed of different starch sources on growth performance andcarcass quality in broiler chickens.To investigate effects of diets composed of different starch sources on growth performanceand carcass quality of broiler chickens,360day-old AA broiler chickens were randomly assignedto3treatments with6replications each treatment, and fed corn, wheat and rice diets, respectively.The results showed that feed conversation rate among the three diets did not have remarkabledifference, but body weight, average daily gain and feed intake of the rice diet was significantlower than the others (P<0.05). However, there was no significant difference on indexes of carcassquality among the three diets composed of different starch sourcesTrail2Effects of diets composed of different starch sources on intestinal developmentand microbial community diversity of broiler chickens.Experimental animals and diets were the same with trail1. At28d,54broilers were selected tokill by injecting4ml5%pentobarbital sodium solution. Each intestinal segment was separated toevaluate intestinal size and weight. Meanwhile, chyme in each segments of each three broilers wasmixed to determine microbial community diversity. Results showed that the lengths of duodenumof broilers fed the rice diet was significant lower than those fed the wheat diet(P<0.05), and thelengths and weights of the other intestinal segments among the three diet treatments had nonotable difference. There were no differences in Shannon-Weiner, Simpson and Evennessindexes among the three diet treatments(P>0.05). As intestinal segment passed backward,microbial species of ileum and cecum were more abundant.Trail3Effects of diets composed of different starch sources on nutrient digestibility inbroiler chickens.Experimental animals and diets were the same with trail1. Excreta were collected every fivedays until30d to determined apparent digestibility of starch and amino acid.5428-old-daybroilers were randomly assigned to3groups, with6replications each group. All broilers werekilled by injecting4ml5%pentobarbital sodium solution, which were separated each intestinalsegments and mixed the chyme in each segment of each replication to analysis starch digestive dynamic. Results indicated that starch digestibility decreased from5d to10d between the corn andwheat group, and then gradually increased in the follow, whose change was in contrast to the ricegroup. Starch digestibility of broilers fed the wheat diet was significant lower than that fed the ricediet(P<0.05). In addition, there was a general trend on AA digestibility that decreased during thefirst10to20d and increased with age from25to30d in all diets. There were significantlydifferent in the digestibilities of some AA among the three diets. The broilers in rice group hadsignificantly higher mean retention time in intestine (P<0.05), but lower fractional starch digestionrate than that in the wheat and corn group. Meanwhile, starch digestibility of jejunum in broilersfed the rice diet was significant lower than those fed the wheat diet(P<0.05). According to theparameters of starch digestive dynamic, it’s known that the amount of potential digestible starchfrom high to low was corn diet, rice diet, wheat diet; the rate of starch digestion from high to lowwas corn diet, wheat diet, rice diet.Trail4Effects of diets composed of different starch sources on glucose metabolism inbroiler chickens.At21d,126broiler chickens were allocated to3groups, with6replications each group, whichfed the corn diet, wheat diet and rice diet, respectively. Adapting to7d, each broiler was fed30gtest diets to determine glucose concentration, glycogen content of liver and muscle, and theexpression of GKS-3β and FAS mRNA at0min、30min、60min、90min、120min、240min、420min,respectively. Results indicated that there were no significant difference in plasma glucose,glycogen concentration of liver and muscles in broilers among the three treaments(P<0.05), butthe significant difference existed in the expressions of GSK-3β and FAS mRNA (P>0.05).Meanwhile, the digestive time affected significantly glucose concentration, glycogen content inliver and breast muscle, as well as the expressions of GSK-3β and FAS mRNA. The higherglycogen content in liver was achieved at240min after the consumption of30g test diet (P<0.05),in contrast, the expressions of GSK-3β and FAS mRNA were lowest in this time. The change ofglycogen concentration in breast and thigh muscle of broilers fed each diet had similar trend.