Efeito dos níveis de metionina+cistina disgestível sobre a morfometria do jejuno de poedeiras leves

Abstract

Methionine is the first limiting essential amino acid for laying hens fed diets formulated with corn and soybean meal. The objective of this study was to evaluate the levels of digestible Metionina+cistina in diets of light laying hens from 42 to 62 weeks of age on the histomorphometry of the jejunum. Six hundred laying hens of the Hy-line W80 line were used, distributed in a completely randomized design with five treatments (0.40, 0.46, 0.50, 0.54 and 0.58) with 12 replicates of 10 birds. At week 62, eight birds per treatment were slaughtered by electronarcosis and the jejunum was collected for histological analysis. The variables analyzed were villus width (LV, μm), villus height (AV, μm), crypt depth (PC, μm), villus:crypt ratio (V:C), villus surface area (VSA, cm) and number of goblet cells (CC). There was a significant effect for VSA, VSA, PC and CC (P<0.05%). Villus height was satisfactory up to the percentage of 0.53% digestible Methionine. The same behavior was repeated for villus surface area and crypt depth and number of goblet cells. However, the largest villus surface area was with 0.56% Methionine. Both for crypt depth and number of goblet cells, the inclusion of 0.50% digestible Methionine showed the best result. However, the variable villus:crypt ratio showed a linear increase as the levels of methionine inclusion in the diets increased. It is concluded that up to 0.56% of methionine maintains the integrity of the jejunal mucosa.