Gene expression and activity of methionine converting enzymes in broiler chickens fed methionine isomers or precursors

Abstract

Common dietary supplemental methionine (Met) sources include DL-methionine (DL-Met) and the Met precursor DL-2-hydroxy-4-(methylthio) butanoic acid (DL-HMTBA). For bio-utilization, D-Met and DL-HMTBA are converted into L-Met through oxidation and transamination. The objective of this study was to determine the effect of different dietary supplemental Met sources on gene expression and enzyme activity of Met oxidases in male broiler chickens. Liver, muscle, duodenum, jejunum, and ileum were collected at days 10 (d 10), 21 (d 21), and 26 (d 26) post-hatch from male broiler chickens that were fed a basal diet deficient in sulfur amino acids (SAA) (control), or the control diet supplemented with DL-Met, L-Met, or DL-HMTBA to meet SAA requirements. The mRNA abundance of D-Met oxidase, L-HMTBA oxidase, and D-HMTBA oxidase was measured by real-time PCR, and oxidase activities were measured using colorimetric assays (n = 5). Liver expressed more D- and L-HMTBA oxidase mRNA, while breast muscle and liver expressed more D-Met oxidase mRNA than other tissues. In the liver, DL-HMTBA and L-Met supplementation were associated with greater mRNA abundance of L-HMTBA oxidase compared to the control diet-fed group at d 10 but not d 21 or d 26. DL-HMTBA supplementation, however, was not associated with changes in the mRNA abundance of D-HMTBA oxidase. The Met-deficient diet at d 26 was associated with greater hepatic abundance of DAO mRNA, which is responsible for oxidation of amino acids. Oxidase activities were similar among the Met deficient and Met-supplemented groups. In conclusion, dietary Met supplementation influenced the transcriptional regulation and activity of Met oxidases in a tissue and age-specific manner. Met oxidases may thus act as a determining factor in the bioefficacy of different dietary supplemental Met sources.

Effects of methionine on muscle protein synthesis and degradation pathways in broilers

“…In contrast to our expectations, the Met source neither affected anabolic nor catabolic pathways in the muscle on the molecular level. This may be explained by the observation that D‐ and L‐HMTBA are converted to L‐Met after absorption primarily in tissues other than the muscle (Martín‐Venegas, Geraert, & Ferrer, ; Zhang, Gilbert, Noonan, Saremi, & Wong, ), thus whatever the dietary Met source, muscle cells will receive primarily L‐Met. In contrast, when D‐Met or DL‐HMTBA were directly supplied to cell types likes myoblasts in an earlier in vitro study significant effects were observed on anabolic pathways compared to cells supplied L‐Met (Métayer‐Coustard et al, ).…”

“…In contrast, when D‐Met or DL‐HMTBA were directly supplied to cell types likes myoblasts in an earlier in vitro study significant effects were observed on anabolic pathways compared to cells supplied L‐Met (Métayer‐Coustard et al, ). This may indicate these cell types are either unable or only partly able to convert these Met sources to L‐Met (Martín‐Venegas et al, ; Zhang, Gilbert, et al, ).…”

“…This may indicate these cell types are either unable or only partly able to convert these Met sources to L-Met (Martín-Venegas et al, 2006;Zhang, Gilbert, et al, 2018a).…”

“…tations, the Met source neither affected anabolic nor catabolic pathways in the muscle on the molecular level. This may be explained by the observation that D-and L-HMTBA are converted to L-Met after absorption primarily in tissues other than the muscle(Martín- Venegas, Geraert, & Ferrer, 2006;Zhang, Gilbert, Noonan, Saremi, & Wong, 2018a), thus whatever the dietary Met source, muscle cells will receive primarily L-Met. In contrast, when D-Met or DL-HMTBA…”

Influence of Different Methionine Sources on Performance and Slaughter Characteristics of Broilers

“…The D-isomer of DL-Met is first converted in liver and kidney by d-amino-oxidase into 2-keto-4 (methylthio) butanoic acid (KMB) and then by transamination into L-Met. MHA, on the other hand, has to be oxidized to KMB in two different enzymatic systems: first by L-2-hydroxy acid oxidase (L-HAOX; mainly located in hepatic and renal peroxisomes) and by D-2-hydroxy acid dehydrogenase (D-HADH; in the mitochondria of various tissues) [26,34,35,36].…”