Body composition, gastrointestinal, and reproductive differences between broiler breeders fed using everyday or skip-a-day rearing programs

Abstract

Broiler breeder feed restriction practices have intensified as broiler feed efficiency has been improved. Skip-a-day (SAD) rearing regimen has controlled breeder growth, although this practice has become questionable for the modern breeder. We compared everyday (ED) and SAD programs and evaluated their impact on pullet growth performance, body composition, gastrointestinal tract development, and reproduction. At d 0, Ross 708 (Aviagen) pullet chicks (n=1,778) were randomly assigned to 7 floor pens. Three pens were fed using the ED and 4 pens with SAD program through wk 21 using a chain-feeder system. ED and SAD grower diets were formulated to be isonutritious, with the only difference that ED diets had more crude fiber. Pullets (n=44 per pen) were moved to 16 hen pens by treatment at wk 21 with 3 YP males (Aviagen) in each pen. All birds were fed common laying diets. In addition to BW data, sampled pullets and hens were scanned using dual energy X-ray absorptiometry (DEXA) to obtain body bone density and composition. Hen performance and hatchery metrics were recorded through wk 60. ED birds were heavier with similar nutrient intake from wk 10 to 45 (P ≤ 0.013). Pullet uniformity was unaffected by feeding method (P ≥ 0.443). SAD pullets had less body fat at wk 19 (P=0.034) compared to ED pullets, likely as a metabolic consequence of intermittent feeding. SAD birds had lower bone density at wk 7, 15, and 19 (P ≤ 0.026). At 4 wk of age, SAD pullets had less intestinal villi goblet cells compared to ED pullets (P ≤ 0.050), possibly explained by the effect that feed removal has on cell migration rates. Overall egg-specific gravity (P=0.057) and hatch of fertile % (P=0.088) tended to be higher in eggs from ED hens. Altogether, ED feeding increased young pullet intestinal goblet cells and increased both bone density and body fat at wk 19. ED program improved pullet feed conversion (2.6% less feed) and increased eggshell quality and hatch of fertile.