Avaliação de propostas de restrição alimentar em frangos de corte.

• Autor(a) principal: Melo, Thiago de Sousa
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/19730
• topic: Zootecnia.; Convencional.; Dark house.; Realimentação.; Taxa de glicose.; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

Advances in genetic improvement, nutrition, environment and health led to an increase in the daily weight gain and reduced the time spent by broilers in sheds, making modern broilers more efficient in the use of feed nutrients. However, it is necessary to seek new management strategies to increase performance and optimize the production cost of broilers. Three experiments aimed to evaluate proposals for feed restriction in broilers. In experiment 1 (E1) the quantitative (QTV) and qualitative (QLV) feed restrictions were evaluated, in experiment 2 (E2) the frequency of diurnal feed restriction (FR) was evaluated, and in experiment 3 (E3) the diurnal and nocturnal FR were evaluated in two poultry production systems (PS). Before starting the experiments, the 425 chicks (Cobb 500®) from E1 and two groups of 1,260 chicks (Cobb 500, Slow Feathering®) from the E2 and E3 were raised and fed with commercial feed. In the three experiments, the chickens were distributed in a completely randomized design as follow: E1 consisting of 5 treatments with 5 five replicates of 17 broilers, E2 consisting of 4 treatments with 9 replicates of 35 broilers, and E3 consisting of a 3X2 factorial arrangement [3 FR X 2 production systems (conventional and dark house)], totaling 6 treatments with 6 replicates of 35 broilers. In E1, the broilers were subjected to the following FR: FR1 = ad libitum intake (AL) from 14 to 42 days old (d), FR2 = QTV of 10% of AL intake from 14 to 28 d and AL intake from 29 to 42 d, FR3 = AL intake from 14 to 28 d and QTV from 29 to 42 d, FR4 = QLV of 10% in crude protein (CP) level and essential amino acids (AAs) from 14 to 28 d and AL intake from 29 to 42 d, and FR5 = AL intake from 14 to 28 d and QLV from 29 to 42 d. In E2, the following feeding restriction programs (P) were evaluated from 8 to 42 days: P1 = AL intake, P2 = suspension of the daily feed supply from 06:00h to 08:00h at the morning (RM), P3 = suspension of the daily feed supply from 01:00h to 03:00h at the afternoon (RA), and P4 = suspension of the daily feed supply in the morning and at the afternoon (RMA). In E3, the AL intake, 4-hour suspension of feed supply at the morning (RM, feed suspended from 06:00h to 08:00h and from 01:00h to 03:00h), and 6-hour of suspension of feed supply at the night (RN, feed suspended from 00:00h to 06:00h) were evaluated: Feed intake (FI), weight gain (WG), feed conversion (FC), carcass yield and cuts (E1, E2, and E3), and bone quality (E2 and E3). In E1, broilers from the AL group had higher WG (p≤0.01) and similar FC (P>0.05) from 14 to 42 d in comparison with those subjected to QTV from 29 to 42 d. Broilers subjected to QTV from 14 to 28 d had lower FI and better FC (p≤0.01) from 14 to 42 days than those subjected to QLV. Broilers subjected to QTV from 14 to 28 d had FC from 29 to 42 d and from 14 to 42 d and economic index similar to those fed AL. Regarding E2, broilers fed AL, RM, RA and RMA had similar body weight (BW), FI and FC (P>0.05) from 8 to 42 days old. However, WG from 8 to 42 d was higher (p≤0.05) in the RMA group than in the AL group. The glucose rate in broilers subjected to RM, RA, and RMA was always lower in comparison to the glucose rate in broilers fed AL, and even lower during fasting compared to the results obtained before and after fasting. Carcass characteristics were similar in all feeding programs (P>0.05). Breakage resistance of bones femurs and tibias was similar (P>0.05), but the Seedor index of the tibia in the AL group was lower (p≤0.05) than those observed in the RMA and RM groups. In E3, broilers fed with RM had FI and WG similar to those fed AL (P>0.05). BW (3,204.62 ± 120.88 vs 3.094.37 ± 46.37 kg), FI (4,481.48 ± 85.65 vs 4,339.31 ± 89.36 kg) and WG (2,958.53 ± 66.71 vs 2,816.67 ± 59.01 kg) were higher (p≤0.05) in broilers from the dark house system than in those from the conventional system. Moreover, broilers kept in DHS had a better feed conversion index (1.515 ± 0.03 vs 1.541 ± 0.03 kg/kg). The abdominal fat weight was higher (p≤0.05) in broilers from the dark house system than in those from the conventional. The Seedor index and breakage resistance of the femur and tibia were similar (P>0.05) between the feeding programs, but the dark house system promoted a higher breakage resistance of the femur and tibia than the conventional (p≤0.05). The RM increased the viability of the broiler stock compared to the AL feed supply (p≤0.05). The dark house system improved the financial result of the broiler batch in comparison with the conventional system. Therefore, a reduction of 10% in ad libitum intake from 14 to 28 days is a viable economic alternative for broilers up to 42 days old. The 4-hour QTV program (2 h in the morning and 2 h in the afternoon) improves the performance and bone and economic quality in broilers. The dark house system offers a higher profitability than conventional system.