The effect of dietary sources on choice-feeding and growth performance of broiler chicks

The present study was carried out to determine whether dietary starch source could affectchoice feeding and growth performance and also digestive system of broiler chicks. A day old 80broiler chicks were divided into 5 treatment groups with similar live weight (38.1 g), containing 16birds each. During the first ten days, broilers were given Standard starter diets (25% CP, 3202 kcal/kgME). Treatment diets were prepared using wheat or corn, besides protein concentrates for wheat orcorn. Feeds of single-fed control groups (groups 1 and 2) for wheat and corn were prepared by mixing50% wheat or corn and 50% protein concentrates for wheat or corn. Choice fed groups, betweencereals and protein concentrates were trained between cereals and protein concentrates from day 11 to14 to accustom between physiological effects and physical properties of the foods given alternatelyevery other day. Then they were given a free choice between wheat and protein concentrate for wheat(group 3), corn and protein concentrate for corn (group 4), corn, wheat, protein concentrates for cornand wheat (group 5) from day 15 to 42.The results showed that birds increased cereal consumption according to the age, and theincrease was found to be higher with wheat than corn. The single fed-wheat group attained higher(P<0.05) body weigh gain and converted energy and protein into weight more efficiently than others.On the other hand, the groups receiving free choice between wheat, corn and protein concentrates forwheat and corn consumed higher (P<0.05) amount of feed, energy and protein than others.The results showed that feeding method and feed source had no effects on carcass yield,carcass weight, total digestive system, ousefagus, crop, proventriculus, gizzard, duedenum, ceacum,weight and length. However, the groups receiving free choice between wheat and protein concentratefor wheat obtained heavier (P<0.05) liver, heavier and longer (P<0.05) jejenum and ileum thanothers, while the group choice-fed between corn and protein concentrate for corn had heavier (P<0.05)large intestine.It could be concluded that cereals source with different starch digestibility rate could affectbroiler performance and choice-feeding, feeding wheat could provide higher growth performance thancorn.Keywords: broilers, choice-feeding, starch source, performance, carcass