Effects of maternal energy efficiency on broiler chicken growth, feed conversion, residual feed intake, and residual maintenance metabolizable energy requirements.

摘要

This study investigated the effect of maternal energy efficiency on broiler chicken growth and energy efficiency from 7 to 40 d of age. Residual feed intake (RFI) and residual maintenance ME requirement (RME) were used to measure energetic efficiency. Residual feed intake was defined as the difference between observed and predicted ME intake, and RME_m as the difference between observed and predicted maintenance ME requirements. A total of 144 Ross-708 broiler breeder pullets were placed in individual laying cages at 16 wk of age. Hens with the greatest RFI (n=32) and lowest RFI (n=32) values from 20 to 56 wk of age were selected (maternal RFI; RFI_mat). Selected hens were retrospectively assigned to a high- or low-RME_m category (maternal RME_m; RME_mmat). At 59 wk, eggs were collected for 8 d and pedigree hatched. A total of 338 broilers grouped by dam and sex were raised in 128 cages where feed intake, BW, and temperature were recorded from 7 to 40 d to calculate broiler feed conversion ratios, RFI, and RME_m. The design was a 2x2x2 factorial with 2 levels of RFI_mat, 2 levels of RME_mmat, and 2 sexes. Neither the RFI_mat nor RME_mmat category affected broiler offpring BW or total conversion ratio. The high-RFI_mat x low-RME_mmat broilers had decreased growth to 40 d. Low-RFI_mat x low-RME_mmat broilers had a lower RME_m (-5.93 kcal of ME/kg0.60 per day) and RFI (-0.86 kcal of ME/d) than high-RFI_mat x low-RME_mmat broilers (RME_m=1.70 kcal of ME/kg0.60 per day; RFI=0.38 kcal of ME/d). Overall, hens with low maintenance requirements (low RME_m) produced more efficient broilers when other efficiency related traits, represented in a lower RFI, were present. Exclusion of high-RFI x low-RME_m hens from selection programs may improve energy efficiency at the broiler level. The RME_m methodology is a viable alternative to evaluate energy efficiency in broilers because it avoids confounding environmental effects and allows measurement standardization.Digital Object Identifier http://dx.doi.org/10.3382/ps.2011-01665