Multigenerational effects of a reduced balanced protein diet during the rearing and laying period of broiler breeders. 1. Performance of the F1 breeder generation.

Studies on mammals and poultry showed that maternal dietary treatments can alter the offspring performance. However, in contrast to rodent studies, little is known about multigenerational dietary manipulations in broiler breeders. The presented research aimed to investigate the effects of a reduction of 25% in the dietary crude protein (CP) level in the F0 generation on the body composition and reproductive performance of F1 broiler breeders. In the F0 generation, breeders were fed either a control (C) or reduced balanced protein (RP) diet, 25% reduction in crude protein and amino acids. Female F0-progeny of each treatment were fed a C or RP diet, resulting in 4 treatments in the F1 breeder generation: C/C, C/RP, RP/C, and RP/RP. The reproductive performance of breeders fed RP diets was negatively influenced by the dietary CP reduction in the F1 generation (P < 0.001). Moreover, breeders descending from hens that received RP diets in the F0 generation showed a significantly reduced reproductive capacity compared to their control fed counterparts (P < 0.001). Breeders fed RP diets in the F1 generation were characterized by higher plasma T3 concentrations (P < 0.001), an increased proportional abdominal fat pad (P < 0.001) and proportional liver weight (P < 0.001). During the rearing phase, the RP fed breeders needed a higher feed allowance, whereas no differences could be observed between the C/C and RP/C or the C/RP and RP/RP breeders. However, breeders originating from birds fed RP diets in the F0 generation needed lower feed allocations in the laying phase to maintain a similar body weight. Egg weight was reduced for the C/RP and RP/RP breeders. At 34 wk of age, eggs from C/RP and RP/RP breeders showed a reduced proportional albumen weight, whereas no effects on egg composition were found at 42 wk of age. It was concluded that prenatal protein undernutrition triggered hens to relocate more energy towards growth and maintenance and less towards reproductive capacity.