Efeito do período de jejum na fase final de criação de frangos de corte machos sobre desempenho e mortalidade

Abstract

The objective of this work was to evaluate effect of fasting period in the last growing phase on performance and mortality of male broilers. Two thousand one-day old male chicks were distributed in five randomized blocks according to a 4x2 factorial. (Four feeding programs (FP): ad libitum or one of three fasting schedules: 8-12, 12-16 and 8-16; and two strains (S): Ross or Hubbard-Peterson). Fifty birds were used per replicate. Birds were raised under identical feed and management conditions until day 42. During the experimental period (days 43-56), average temperature, relative humidity and temperature-humidity index (THI) recorded at day and at night were 29.4°C, 57.7 % and 78.1; and 22.0°C, 73.1% and 67.4, respectively. No SxP interaction was observed for all characteristics studied. At day 56, the Ross broilers showed higher mean weight (3104 g), weight gain, WG (3059 g), feed/ gain ratio, FC (2.22) and production factor, PF (213), than the Hubbard-Peterson birds (3011, 2967, 2.28 and 194, respectively). During the experimental period, the Ross broilers showed higher WG (831 g) and FC (3.40) than the Hubbard-Peterson ones (770 and 3.67, respectively). Birds submitted to the 8-12 h fast showed higher feed intake (2864 g) than those that fasted during the 8-16 period (2690). No effect of P on mortality was observed, either considering the overall period (days 1-56) or the experimental period (days 43-56). Fasting in the last phase of rearing not aided by other practices failed to decrease heat stress effects on performance and mortality of male broilers.