A low-crude protein diet for broiler breeders changes body composition during the rearing period. This positively affects hatchability during the first phase and egg production during the second phase of the laying period.

Economical calculations show that these improved performance measures result in an increased profit of €0.53 per breeder or about €12,500 for an average broiler breeder farm per year.

Increased Hatchability and Egg Production

Poultry scientist, Rick van Emous, of Wageningen UR Livestock Research investigated the effect of two dietary protein levels (high and low) during rearing on, feed intake, body composition at the end of the rearing period and reproductive performance of broiler breeder females. A total of 2,880 one-day old Ross 308 broiler breeder female chicks were placed in 36 pens and followed until 60 weeks of age.

To meet bodyweight target at 22 weeks of age, average feed intake increased by 12.8 per cent for the pullets fed the low-protein diet.

At 22 weeks of age, birds fed the low-protein diet had 15 per cent less breast muscle but 86 per cent more abdominal fat than the high-protein-fed birds. This resulted in an 1.3 per cent increased hatchability due to a decreased embryonic mortality in the first phase of the laying period (23-45 weeks of age).

Moreover, low-protein fed birds produced 3.6 more hatching eggs during the second phase of the laying period (46-60 weeks of age).

Economical calculations show that feeding a low-protein diet resulted in an increased profit of €0.53 per breeder or about €12,500 for an average broiler breeder farm per year.

Changing Body Composition Affects Reproduction

Mr van Emous noticed that over recent decades, the genetic potential of broiler breeders increased due to selection on growth of the offspring. The growing period of broilers decreased from 84 to 33 days to produce a broiler weighing 1.8kg. Its feed conversion ratio decreased in the same period from 3.25 to 1.50 and the daily growth increased from 21 to 55g.

This selection on increased feed conversion, growth rate and body fat content has not only affected the offspring but also the parent stock (broiler breeders). Optimising body composition (more fat and less breast meat) of female broiler breeders during the rearing period might improve persistency of the reproductive performance.

The study is part of a PhD project on body condition and nutrition in broiler breeders. It was carried out by Wageningen UR Livestock Research and financed by the Dutch Product Boards for Livestock, Meat and Eggs (PVE), the Product Board Animal Feed (PDV) and Aviagen-EPI.