Energy restriction in broiler breeders during rearing and laying periods and its influence on body weight gain, conversion efficiency of nutrients, egg production and hatchability

Abstract

The effect of feeding measured energy (ME) allowances during rearing and laying periods on body weight (BW) gain, production performance and hatchability were evaluated in a female broiler parent line. In grower period (5-20 wk), ME required for maintenance, activity and growth was calculated targeting 100 g increases in BW/week in control (C) group. In another group, ME was quantitatively reduced by 20% (R) over C. Both groups were offered measured quantity of grower diet to satisfy the scheduled energy inputs. At 21 weeks, C and R groups were individually sub-grouped into four each, to either restrict energy severely (S-20%), moderately (M-10%) or increase (E-10%) over control. Thus, 8 sub-groups were formed: CS, CM, CC, CE and RS, RM, RC, RR. The CC and RC sub-groups were offered calculated ME for 50g increase in BW/week and anticipated egg production. Measured amount of breeder diet was offered to each sub-group following energy schedule. At 20 weeks, significant increase in BW was observed in C-group with better conversion efficiency of feed, energy and protein compared to R-group. The R-group had lesser abdominal fat and liver weights, higher muscle protein and lower fat than C-group. Breeders in R-group matured late by 7.7 days, but produced significantly more eggs with better-feed efficiency up to 64 weeks than C-group. In laying phase, breeders maintained on 20 and 10% less energy (RM) during rearing and production periods, respectively matured late, but produced significantly more eggs with higher persistency than CC. At 68 weeks, maximum fertility and hatchability on total eggs set was recorded in RM sub-group. These results showed complimentary influence of grower and breeder energy restriction on egg and chick production and saved feed, substantially in RM sub-group. It appeared that the energy requirement under energy restriction was lesser than that calculated. Copyright © 2008, Japan Poultry Science Association.