NÍVEIS DE FIBRA SOLÚVEL E INSOLÚVEL PARA AVES DE CRESCIMENTO LENTO NA FASE INICIAL DE CRIAÇÃO

Abstract

The creation of slow-growing chickens or "poultry" has evolved in recent years in Brazil. Several researches have been carried out to improve nutritional utilization and productive indexes. The objective of this study was to evaluate the soluble and insoluble fibers inclusion effect in diet on production and digestive development of slow-growing chickens in the breeding initial phase. A total of 400 male, one-day-old Isa Label males were used. The treatments were distributed in a completely randomized design in a 2 x 2 +1 factorial arrangement (soluble and insoluble fiber, inclusion level of 2 and 4% of the fiber source and a control treatment), with eight replicates of 10 birds per plot. Performance, carcass yield and cuts, digestive development, diets nutritional use and intestinal histomorphometry were evaluated. The corn cob addition in rations improved the birds weight gain and feed conversion at seven and 21 days of age. Regarding the carcass characteristics, only abdominal fat levels were positively affected by fiber inclusion in diet. Although fiber inclusion reduced the overall length of the gastrointestinal tract, it was found that, independently of the source, the fiber addition to diet provided higher relative weights of proventriculus + gizzard, small intestine, large intestine and liver. The 4% corn cob inclusion was more effective in increasing the proventriculus + gizzard weight than for the development of other organs of the gastrointestinal tract such as the small intestine and pancreas. It was found that the positive effects of fiber addition on intestinal development were more pronounced when using the soluble source (citrus pulp). The use of 2% citrus pulp in diet of slow growing chicks increased the cecal villi height. However, positive effects of adding corncob to the cecal villi height were verified when this source was included at 4% levels in diet. The 4% corn inclusion in the ration improves performance, nutrient metabolism and proventriculus + gizzard development of slow growing chickens. However, the citrus pulp addition in diet improves the morphological and intestine histomorphological development of slow - growing chickens in the rearing initial phase.