Effect of amino acid supplementation of low protein diets for layers and all-plant protein diets for broilers

Abstract

The first study was undertaken to determine the feasibility of supplementing low protein diets with the two most commonly limiting amino acids in laying diets methionine and lysine. Individually caged incrossbred pullets were subjected to eight different treatments for twelve 28-day periods. A positive control diet containing 16.3% animal and plant protein, 2068 kcal./kg. productive energy, 0.778%, lysine and 0.536% methionine plus cystine, was compared to a negative control 14% plant protein diet formulated to contain 0.656% lysine, 0.460% methionine plus cystine and 2068 kcal./kg. productive energy. This diet was supplemented with 0.075% and 0.125% methionine; 0.050% and 0.100% lysine; 0.075% methionine plus 0.050% lysine and 0.125% methionine plus 0.100% lysine, respectively. Egg production, egg size and feed efficiency were approximately equal for the unsupplemented 14% protein and for this diet supplemented with either 0.075%, 0.125% methionine or 0.050%, 0.100% lysine. The combination of methionine plus lysine at the lower level significantly improved these economic traits and was greater than or equal to the response to the higher of both or to the positive control diet. The second study was undertaken to study the performance of commercial broilers. Fourteen diets containing either glandless cottonseed meal (GCSM), cottonseed meal (CSM), sesame meal (SM), soybean meal (SBM), or combination of these plant protein sources, with and without amino acid supplementation, (methionine and/or lysine) end in each case contributing the same total amount of crude protein, were compared to each other and to a positive animal and plant protein control diet. ...