Evaluation of feed transit time, certain liver and pancreas related parameters as the sources of shared intra-flock variationin performance indices in broiler chicken

Three hundred male chicks were used to examine the effects of early growth rate (x̄-۳SD, x̄-۲SD, x̄-SD, x̄, x̄+SD, x̄+۲SD,x̄+۳SD) and a fat soluble vitamin (FSV) cocktail on whole tract feed transit time, certain liver and pancreas related traitsas well as their share in intra-flock variance of performance indices.Birds with a greater initial BW (۲۱d) demonstrated greater weight gain (WG) and feed intake (FI)during days ۲۱ to ۴۲ of age. The broilers injected witha FSV cocktail consumed more feed with an improved feed conversion ratio (FCR), gained greater weight and finally achieved a noticeable greater BW day ۴۲. Performance indices were found to be weakly correlated with serum lipase and amylase activity. Multivariate stepwise regression analysis showed liver percentage as the leading variable accounting for about ۷۵ and ۶۲.۷۷ percent of BWand FI variance, respectively (Table ۵). Serum cholesterol concentration was the major predictor in apoor model (R۲=۵۲.۰۷) generated for FCR, explaining ۲۹.۳ of the FCR viability (P<۰.۱۵۰). The faster-growing birds demonstrated slower feed transit time. Liver percentage was the major parameter explaining a significant fraction of the intra-flock variance in BW at marketing age and FI during days ۲۱ to ۴۲ days.

کلیدواژه ها:

Broiler chicken ، Feed transit time ، Intra-flock variability