Energy and protein dilution in broiler breeder pullet diets reduced offspring body weight and yield.

The objective of the current research was to evaluate transgenerational effects of maternal dietary energy and protein on growth, efficiency, and yield of broiler offspring. A factorial arrangement of treatments consisting of high and low ME and CP levels fed during the rearing and laying phases was used. The study was a final 2 × 2 × 2 × 2 factorial arrangement of treatments, including broiler sex. Ross 708 broiler breeder pullets (n = 933) were fed diets containing 2,736 (HEREAR) or 2,528 kcal/kg ME (LEREAR) with either 15.3% (HPREAR) or 13.7% CP (LPREAR). From 25 wk, dams were fed a 15% CP laying diet containing 2,900 (HELAY) or 2,800 kcal/kg ME (LELAY). Following artificial insemination of the dams at 35 wk, eggs were collected for 1 wk, incubated, and pedigree hatched to preserve maternal identity. Broiler offspring were placed sex-separately into 32 pens, according to laying phase maternal treatments, with rearing maternal treatments nested within pens. Individual BW and pen level feed intake were recorded weekly. Broilers were processed at 40 d of age to evaluate yield. Maternal diet effects on offspring BW were sex dependent and transient. Female LPREAR × LELAY broilers had lower pectoralis major and carcass yield than HPREAR × LELAY females. Male HPREAR × HELAY broilers had increased breast yield (19.8%) compared with 18.4% in HPREAR × LELAY broilers. Carcass yield was lower in LEREAR × HPREAR broilers (63.7%) compared with HEREAR × HPREAR broilers (64.9%). LEREAR × HPREAR dams had the lowest ME to CP ratio (E: P) diets and highest rearing phase CP intake. Maternal diet did not influence offspring FCR. The most consistent contributor to increased BW was higher maternal dietary CP and ME during rearing. Low ME maternal laying phase diets increased BW of male offspring more consistently than of female offspring. Maternal nutrition also influenced broiler yield, and is thus economically important. Energy and protein dilution in broiler breeder pullet diets may have detrimental effects on offspring performance.