Desenvolvimento do sistema digestório e da capacidade digestiva de frangos de corte alimentados com diferentes níveis de energia metabolizável

Abstract

The objective of this study was to evaluate the effect of diets with different metabolizable energy levels on the development of the digestive system and digestive capacity of broilers. This experiment employed a 4x9 factorial design (metabolizable energy levels: low, medium, high and very high; x age: every three days until 28 days old). Four birds from each treatment were euthanized and had body weight, relative weight of various components of the gastrointestinal tract (GIT) and accessory glands and the relative length of intestinal segments evaluated. Characteristics of villi and absorptive surface area of the duodenal mucosa were evaluated. Digestibility was evaluated using the method of total excreta collection. The metabolizable energy level did not influence the development of the TGI and accessory glands of broilers, with the exception of the ileum. From 21 days of age, it s possible to increase the metabolizable energy without harming the digestibility of fat, indicating that from this age the broilers can digest greater amount of fat. The birds until 27 days old best digested nutrients in diets with medium metabolizable energy level. The energy level of the diet differently influenced the digestibility of nutrients, and in the period studied, the highest rate of digestibility was up three days of life, with a sharp decline until the period of seven to nine days of age and an increase from this period without, however, reach the digestibility of the first three days of age.