Partial replacement of DL-Methionine and methionine hydroxy analogue with betaine in diets for broiler chickens

L Silva,R.V Nunes,A.S Avila,B.S Vieira,C Souza,P.S Cella,S.E Takahashi,J Broch,L.D Castilha

doi:10.4314/sajas.v51i4.14

Abstract

The study evaluated the effects on the growth performance and carcass characteristics of broiler chickens of DL-Methionine (DL-Met) and methionine hydroxy analogue (MHA) supplementation and their partial replacement with betaine (Bet). Two experiments were performed from day 1 to 21 and from day 22 to 42. Broiler chickens were assigned to six treatments, in a completely randomized design and a 2 × 2 + 2 factorial arrangement, consisting of two Met sources (DL-Met and MHA), with or without Bet, and two negative controls. The six treatments consisted of i) NC-DLM: negative control for DL-Met with 7% reduction in DL-Met; ii) NC-MHA: negative control for MHA with 7% reduction of MHA, iii) DLM100: without Bet, supplemented exclusively with DL-Met reaching 100% of requirements, iv) MHA100: without Bet supplemented exclusively with MHA reaching 100% of requirements, v) DLM93+Bet: DL-Met at 93% of recommended level plus betaine; vi) MHA93+Bet: MHA at 93% of recommended level plus betaine. Growth from day 1 to 21 was not altered by methionine source or betaine supplementation. However, the negative controls had numerically less weight gain and feed conversion ratio (FCR) . Between days and 42 there were no effects on growth. Betaine could partially replace methionine without altering the growth of broiler chickens. In addition, the partial replacement of DL-Met with betaine increased body crude protein content. However, its use increased body fat content regardless of methionine source.

Highlights

Methionine is one of the more limiting amino acids in animal nutrition, with an important function in protein synthesis
The methyl groups found in betaine may provide benefits by sparing methionine as a methyl donor and permitting methionine to be directed towards protein synthesis (Sun et al, 2008; Nutautaitë et al, 2020)
The treatments consisted of two methionine sources, two betaine supplementation levels, and two negative controls

Summary

Introduction

Methionine is one of the more limiting amino acids in animal nutrition, with an important function in protein synthesis. It is a source of methyl groups, which are important in metabolism and must be supplied in the diets as they cannot be synthesized (Sun et al, 2008; Nutautaitė et al, 2020). The usual supplemental sources of methionine are DL-Met and MHA (Payne et al, 2006), which is chemically different from DL-Met because it has a hydroxyl group at the asymmetric carbon atom, whereas DL-Met has an amino group. On a molecular weight basis, betaine contains about 3.75 times more methyl groups than methionine, and have been shown to counteract the partial deficiency of labile methyl groups in corn-soybean-based diets (Rama Rao et al, 2011; Sun et al, 2008)

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