Adição de carboidrases e proteases na dieta de frangos de corte

Abstract

The objective of this research was to evaluate the influence of supplementation of levels of carbohydrates and proteases in diets with energy and protein reduction, and their impact on the production of broilers. In total, 1800 day-old male broiler chicks with an average initial weight of 45.47 grams were used in the initial phase. The birds were distributed in a completely randomized design with a 2x2 factorial scheme, with 8 treatments with 9 replicates and 25 birds per EU. A positive control diet (CP) (which aims to meet all nutritional requirements), a negative control diet (NC) (with nutritional reduction of 100 kcal kg-1 and 4% CP) and T3 = CN + 50 g ton-1 of carbohydrase and 0 g ton-1 of protease, T4 = CN + 100 g ton-1 of carbohydrase and 0 g ton-1 of proteaseT5 = CN + 0 g ton-1 of carbohydrase and 60 g ton-1 of protease, T6 = CN + 0 g ton-1 of carbohydrase and 125 g ton-1 of proteins, T7 = CN + 50 g ton-1 of carbohydrase and 60 g ton-1 of protease, T8 = CN + 100 g ton-1 of carbohydrase and 125 g ton-1 of protease. Rations and water were provided ad libitum throughout the experimental period (42 days). Subsamples of all dietary treatments (500g of feed) were collected and analyzed for the contents of dry matter, crude protein, crude energy, mineral matter, acid insoluble ash (CIA). For all experimental diets, enzymes were included in place of corn. Weight and feed intake were recorded at 7, 21, 35 and 42 days of age, to assess feed intake (CR), weight gain (GP) and feed conversion (CA). Two birds per EU at 21 and 42 days of age, selected at random, were fasted for 6 hours, for blood collection via brachial puncture. At 42 days of age, three birds per EU were euthanized and necropsied, for later removal and weighing of the organs (liver and pancreas), determination of carcass yield, cut yield (breast, sassami, feathers and wings), percentage of fat abdominal removed from the cloaca and around the gizzard and ileum content.The statistical software used for the evaluations was SAS (SAS [marca registrada] University Edition (2017) (SAS Inst. Inc., Cary, NC, EUA). There was a significant effect on performance (P <0.05) for the variable weight gain (GP) and feed conversion (WC) at 21 days of age. There was a significant effect (p <0.05) for the variables hot carcass yield (CQ), cold carcass yield (CF), leg yield, wing yield and sassami yield. For liver and pancreas variables, there was an influence (p <0.05). There were no significant results (p> 0.05) for the abdominal fat variable. Regarding blood parameters from 1 to 21 and 1 to 42 days, they did not interact with the inclusion of enzymes (p> 0.05). There was an effect (p <0.05) for digestibility coefficient of crude protein when the combination of carbohydrase and protease with levels of 100-0 was used, whereas for the variable gross energy the best result was found in the combination of enzymes being the inclusion 100-125 the best answer. Energy reduction affected performance, carcass characteristics and ileal digestibility of broilers from 1 to 42 days.