Evaluation of L-methionine excess and deficiency in broiler chicken diets through stable carbon isotope technique

Abstract

It is notorious the high importance of levels adequacy of essential amino acids in diets for poultry, particularly methionine, and the wide applicability of stable isotope techniques in biological studies. In this context, this study will aim to use the stable isotope techniques to assess the process of incorporation rate and mass balance of 13C from L-methionine, in tissues of broiler chickens at different periods of growth, considering excess and deficiency conditions of it in diets. A total of 1,000 male Cobb broiler chicks will be housed and after selection by weight will be distributed 351 birds in each of the three groups (G): G1 - diet with recommended levels in methionine (MET), G2 - diet with 30% deficiency of recommendation in MET, and G3 - diet with 30% excess of recommendation in MET. Each group will be evaluated during the periods 1-14, 15-28, 29-42 days old. The birds will be subjected to oral administration of a solution containing L-[13C1]methionine (99 atm % 13C), at a dose of 29 µmol/kg body weight/h within 6 h, in each group and period studied. At 0 (control), 1, 3, 5, 7, 9, 12, 16, 20, 24, 48, 72, and 96 hours, after the first administration of enriched solution, 3 birds will be slaughtered by time period for each group and period evaluated for tissue sampling used in isotopic analysis in mass spectrometer. Samples will be taken from the duodenal mucosa (DM), plasma (P), liver (L), chest (C), feathers (F), abdominal fat (AF), and excreta (EX). The data obtained by isotopic analysis, will be analyzed using Minitab 16 statistical software. (AU)