Effects of Feeding Varying Levels of DL-Methionine on Live Performance and Yield of Broiler Chickens.

Anthony Pokoo-Aikins,Byungrok Rok Min,Jennifer Rumsey Timmons,Samuel Njoroge Mwangi,Chongxiao Chen,William Robert Lee

doi:10.3390/ani11102839

Abstract

Simple SummaryThe use of DL-methionine (MET) in poultry diet formulation is vital for poultry growth because poultry do not synthesize sufficient amounts of MET needed for proper growth and performance, and currently there are insufficient natural sources of MET to fulfill the dietary needs of broiler chickens. However, the use of MET is restricted in the United States in organic poultry diets. Therefore, the objective of this study was to examine the effect of feeding different levels of dietary MET on organic broiler live performance and yield of a modern commercial broiler strain. This study gives us insight into how broiler growth and yield is affected when the allowable levels of methionine for organic broilers is further reduced, or zero methionine is used.This study was designed to evaluate the effects of dietary supplemental DL-methionine (MET) on live performance and meat yield for broilers raised to a common weight. A total of 1552 one-day old Ross 708, sexed broilers were randomly distributed to 32 pens resulting in eight treatments (TRT) of four replicates with 44 male or 53 female/pen. A randomized complete block with a 2 × 4 (sex × 4 MET levels 0, 0.5, 1, and 2 g/kg) factorial arrangement of TRT was used. A common weight of 2400 g was approached by day 46 (1 and 2 g MET/kg feed) and day 48 (0 and 0.5 g MET/kg feed). Supplementation of MET at 1, and 2 g/kg had a lower (p < 0.01) feed conversion ratio (FCR) at day 46/48 than broilers fed 0.5 g MET/kg. Broilers without supplemental MET had the worst (p < 0.01) feed conversion and average daily gain (ADG) at day 46/48. Birds fed 0 g MET/kg of feed had lower (p < 0.05) whole eviscerated carcass without giblets (WOG), yield than birds fed 2 g MET/kg of feed. Additionally, birds fed 0 g MET/kg of feed had lower (p < 0.05) breast fillet and tender percent yields than birds fed supplemental MET. Elimination of MET from organic broiler diets resulted in reduced ADG, breast fillet yield and feed efficiency of meat yield of broilers raised to day 46/48. Reduction in MET supplementation below current levels reduced the efficiency of meat production of organic broilers raised to day 46/48.

Highlights

Methionine (MET), a sulfur containing amino acid, is considered an essential amino acid in poultry because poultry cannot naturally synthesize sufficient amounts to sustain normal body functions [1]
Ross broiler nutrition specifications for conventional broilers raised to 2.50–3.00 kg target live weight states the total methionine requirement for maximum weight gain, feed and feed efficiency are 0.56, 0.51, 0.47, and 0.44% for starter grower, finisher one and finisher two, respectively
In this study the focus was on organic broiler nutritional requirements, which are much lower than the requirements for Ross broilers for growth, performance and meat yield in terms of methionine

Summary

Introduction

Methionine (MET), a sulfur containing amino acid, is considered an essential amino acid in poultry because poultry cannot naturally synthesize sufficient amounts to sustain normal body functions [1]. Supplemental MET in broiler diets have been shown to improve body weight (BW), feed intake (FI), feed conversion ratio (FCR) and average daily gain [3]. In the US, MET is the only allowed synthetic AA in organic poultry feed [7], in October, 2012 the USDA reduced the amount of MET that can be used in organic poultry diets from 2, 2.5, and 3 kg per metric ton (4, 5, and 6 lbs per ton), to 1, 1, and 1.5 kg per metric ton In a 2015 review by the National Organic Standards Board (NOSB), the average MET limit over the life of organic broilers is approximately 1.25 g MET per kg of feed (2.5 lbs per ton of feed) [9]

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