Evidence of a Different Dose Response in Turkeys When Fed 2-Hydroxy-4(Methylthio) Butanoic Acid Versus dl-Methionine

Abstract

In broilers, 2-hydroxy-4(methylthio) butanoic acid (HMTBA) can elicit a different dose response relative to dl-Met (DLM) such that birds could have lower gain responses at deficient TSAA concentrations but greater gain responses at maximum response concentrations. Two experiments tested if the 2 Met sources have a different dose response in 1-d-old turkeys using a 2 x 4 factorial plus a control design with 8 replicates of 12 toms per treatment. 2-Hydroxy-4(methylthio) butanoic acid and DLM were supplemented at equimolar concentrations of 0.05, 0.10, 0.15, and 0.20% or 0.04, 0.08, 0.16, and 0.32% for experiments 1 and 2, respectively, in commercial-type TSAA-deficient (0.99 to 1.02%) diets for 21 d. No differences in any performance parameter tested were found between HMTBA and DLM in either trial by ANOVA. Linear (LIN), quadratic (QUAD), and exponential regressions were fitted to the gain response of birds fed HMTBA or DLM. Equations with better goodness of fit as determined by Schwarz's Bayesian information criteria index were used for further calculations of predicted differences between HMTBA and DLM. In both trials, the shape of the dose response differed according to the Met source used, and best-fit equations were obtained when using Met intake over control rather than dietary Met concentration as the dependent variable. In experiment 1, the best-fit equations were an inverse QUAD for HMTBA and a LIN for DLM, and in experiment 2 with higher Met concentrations, the best-fit equations were a QUAD for DLM and a LIN for HMTBA. Feeding HMTBA at deficient TSAA resulted in lower (P <0.05) gains in experiment 1 but greater gains at maximum response concentrations (P <0.05) in both experiments. Plasma-free Met increased at 3 times the rate for DLM than HMTBA (P <0.01) with increasing Met concentration, which may play a role in the evolution of different dose responses at the extremes of the Met dose response. These results demonstrate that Met sources elicit a differential dose response in turkeys such that feeding HMTBA at deficient TSAA concentrations can be lower than DLM and can reach a higher maximum performance than with DLM.

2‐Hydroxy‐4‐methylthio butanoic acid and DL‐methionine for Japanese quails in production

“…With this evaluation, the digestible Met+Cys was same in the diets independent of sources evaluated, reducing the chances of equivocal equivalences, and bioavailability in consequence, or effects without efficient measurement of sources. Thus, the evaluations and applications with methionine sources should be performed by equimolar basis, allowing better results in alternative source efficiency and poultry performance, corroborating with (Gonzales‐Esquerra et al., ; Vazquez‐Anon, Kratzer et al., Vazquez‐Anon, Gonzalez‐Esquerra et al., ).…”

“…The efficacy clearly depends upon the type of diet and supplementation level, with supplemental, amino acid‐based, purified experimental diets apparently favouring DLM‐99%. However, poultry fed commercial diets containing HMTBA may have better responses than poultry fed diets with DLM‐99% at practical levels of supplementation (Gonzales‐Esquerra et al., ;Vazquez‐Anon, Kratzer, Gonzalez‐Esquerra, Yi, & Knight,; Vazquez‐Anon, Gonzalez‐ Esquerra et al.,). This efficacy is such that HMTBA is used as a methionine source in the poultry industry in United States of America, with an 85 to 88% bioefficacy level for liquid methionine.…”

“…In reality, diets should be formulated based on the concentration of active products (equimolar comparison) to conduct a proper comparison, that is, HMTBA‐88% and HMTBA‐84% and DLM‐99%. This way, experimental diets will have the same digestible methionine concentration (Gonzales‐Esquerra et al., ; Vazquez‐Anon, Kratzer et al.,; Vazquez‐Anon, Gonzalez‐ Esquerra et al.,).…”

The immune response of young turkeys to haemorrhagic enteritis virus infection at different levels and sources of methionine in the diet

“…DL-methionine (DLM) or DL-methionine hydroxy analogue (MHA) [43]. Chemically, MHA is not an amino acid but a metabolic precursor of DLM and a very effective source of supplemental Met [7, 41]. Some studies have revealed MHA to be more effective in improving the antioxidant status of chickens and turkeys than DLM [25, 38, 42].…”

Bioavailability of different dietary supplemental methionine sources in animals

“…They concluded that these two methionine sources had a different dose-response, with HMTBA outperforming DL-Met at commercial levels and DL-Met outperforming HMTBA at total dietary sulfurcontaining amino acid (TSAA) deficient levels (41). Similar results were observed in turkeys, with feeding supplemental HMTBA to young male turkeys for 21 days leading to a lower growth but greater maximum response compared with DL-Met at TSAA deficient levels (42).…”