Ganho de peso compensatório em diferentes fases na criação do frango de corte
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2021-05-18
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Universidade Federal de Goiás
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This experimental trial was designed with the objective of evaluating a possible compensatory weight gain in broilers at different ages submitted to a quantitative food restriction program. Fully randomized experimental design (DIC), with 5 treatments and 7 repetitions with 32 birds per repetition, totaling 35 experimental plots, totaling 1,120 birds. The treatments consisted of quantitative food restriction of 20% of the expected weekly consumption of the cobb table, separated by week: treatment with food restriction in the second week, treatment with food restriction in the third week, treatment with restriction in the fourth week, treatment with restriction in the fifth week, sixth week with free feeding for all treatments and control treatment without restriction. The collected data were submitted to ANOVA and were evaluated by contrast. In the weekly performance the feed consumption was always low in the treatment of the week restriction when compared to the control treatment, in consequence, the average weight was also lower in the same week, and the conversion was always higher in the week of the restriction. At 42 days, these differences were not observed, suggesting that there was weight recovery, that is, the broiler chicken with a 20% restriction managed to show compensatory weight gain. For organs and tissues, there was a significant difference between treatments in the relative weight for gastrointestinal tract and large intestine, presenting a lower index in the week that the birds went through food restriction. As for intestinal histomorphometry, in general, villus height and crypt depth were higher in treatments that underwent food restriction, since the intestinal epithelium of birds is constantly renewed by mechanisms of intestinal muscosa repair, which can be changed by agent nutrients, which makes them hyperplastic, with deeper crypt depth. For evaluation of woody chest degrees, there was a better result (reduced incidence) for the animals that underwent restriction in the second and fifth week. When examining the means of microscopic lesions of the pectoralis major muscle, a difference is observed only in adipose tissue. It was concluded that birds with a 20% restriction were able to regain weight and present compensatory weight gain. With regard to organs and tissues, there was a decrease in the weight of intestinal organs due to a decrease in peristaltic movements in the face of a period of restriction, requiring less from the intestine and, consequently, decreasing its relative weight. Likewise, the birds' organisms react to food restriction at the cellular level, increasing villus height and crypt depth as a mechanism to improve nutrient absorption and increase tissue repair. With regard to pectoral muscle changes, the restriction applied in this study was able to reduce the incidence of wooden breast.
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TEODORO, J. C. Ganho de peso compensatório em diferentes fases na criação do frango de corte. 2021. 62 f. Dissertação (Mestrado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2021.