Influence of Diet Physical Form and Fines Proportions in Pellet Diet on Feed Quality, Performance and Microbial Population in Digestive Organs of Broiler Chickens

Abstract

Two experiments were conducted to investigate the effect of physical forms and fine proportions in pelleted diets (simple pellet and expanded pellet) on the performance of broilers. In Exp. 1, 360 one day old male chicks were used to evaluate the effects of different physical forms on performance and microbial population in the digestive organs. Body weight (BW) gain of broiler chickens fed pelleted diets was improved. Pellet physical quality analysis showed a lower pellet hardness and pellet durability index for simple pellet compared with expanded pellet (P<0.05). Moreover, the fines rate in expanded pellet was lower than simple pellet. Regardless of pelleting method, broilers fed pelleted diets exerted lower relative weight of gizzard, higher pH in gizzard and lower pH in jejunum, ileum and cecum than those of broilers fed mash. Broilers fed simple pellet diet had higher jejunal weight than the expanded pellet diet. Pellet fed broilers had lower numbers of coliforms in cecum than mash fed broilers. In Exp. 2, 480 one day old male Ross 308 chicks were used to evaluate the effect of fine proportion in pellet diet on performance and microbial population in different digestive organs. The BW gain of broilers decreased linearly as the fine proportion increased. Feed conversion ratio was tended to be linearly higher (P=0.057) with decreasing proportion of fines. Collectively, our data indicate that high quality pellet has the potential to improve growth performance, but no difference between simple pellet and expanded pellet diet. Furthermore, increasing the rate of fines linearly decrease the growth performance of broilers.