| Resumo: |
ABSTRACT The fast-growing Brazilian aviculture requires studies to improve zootechnical performance indexes for broiler breeders. The purpose of this study was to assess different feeding programs for broiler breeders on performance and development of digestive organs. A total of 48,000, 1d-old, Cobb 500 broiler breeders were divided into two sheds with 24,000 birds each. The experiment was randomized in block design, considering each shed a block, with 4 treatments and 6 replications per treatment with 2,000 birds in each. Treatments consisted of: Shed 1) T1 = starter feed; T2 = T1 + probiotics; Shed 2) T3 = pre-starter feed; T4 = T3 + probiotics. The productive performance characteristics (bird weight, weight gain, feed intake and feed conversion), the development of digestive organs (gizzard, proventriculus, spleen, bursa of Fabricius and small bowel) as well as the small bowel length were assessed weekly for all experimental groups, in samples of 10 birds per treatment. The best feed conversion and weight gain were observed with pre-starter feed in the first 7 days of age, with or without probiotic. Small bowel, gizzard and proventriculus development at 28 days was better for birds on pre-starter feed compared to those on starter feed alone. It is possible to conclude that broiler breeders on pre-starter feed during the first 7 days of age are likely to show better physical and productive performances in the adult phase.
|
