Utilization of Methionine Sources for Growth and Met+Cys Deposition in Broilers

Abstract

Knowledge about the nutritional value of methionine sources is highly important for their appropriate application in terms of animal and economic performance. Therefore, a broiler feeding trial was conducted to determine the relative bioavailability value (RBV) of DL-2-hydroxy-4-methylthio butanoic acid (HMTBA) compared to DL-methionine (DLM). DLM diluted to 65% purity (DLM65) served as the internal standard, with a known RBV of 65%. A total of 1920 d-old male broilers were used in the three-phase feeding trial comprising 16 treatments including a basal, Met+Cys-deficient diet and 5 graded DLM, HMTBA, or DLM65 levels. Growth performance and carcass quality data were subjected to multi-exponential regression analysis. Increasing levels of any Met source significantly improved all performance parameters compared to the negative control (p < 0.05). Across all performance parameters, the RBV of HMTBA was 63% and that of DLM65 was 58%. All RBV estimates of HMTBA and DLM65 were significantly lower than 88% (p < 0.05). Cumulative efficiency of DLM for Met+Cys deposition in body protein was higher than that of HMBTA at any dose, confirming the determined RBV. Using DLM65 as an internal marker allowed for validation of the methodology.

A planetary health perspective on synthetic methionine

“…The amount of methionine supple ment added to the fodder is generally calibrated to meet the requirement for the target species to reach its upper limit of body protein deposition (table 2). 27 Other markets for synthetic methionine include a rumen-protected form for dairy, formulations for aquaculture and pet foods, and pharmaceutical applications.…”

Evaluation of Methionine Sources in Protein Reduced Diets for Turkeys in the Late Finishing Period Regarding Performance, Footpad Health and Liver Health

“…Nevertheless, their research indicated that balancing amino acids beyond lysine, methionine + cysteine, threonine and tryptophan were needed to achieve the same FCR and breast meat deposition as with protein reduction including the entire range of essential amino acids. Indeed, Lemme et al [6] were able to at least maintain BW gain and FCR when reducing the protein level of commercial type diets by 1% point and balancing for lysine, methionine + cysteine, threonine, arginine, valine and isoleucine. However, meat deposition was slightly affected.…”

“…In addition, less nitrogen has to be excreted which reduces the water requirement [54]. Assuming 33 g nitrogen/kg weight gain and analysed protein levels of the experimental feeds, average nitrogen depositions of 149, 140, 165, and 160 g/bird and nitrogen intakes of 314, 295, 390 and 372 g/bird can be estimated for birds of treatments LP + DLM, LP + MHA-FA, HP + DLM and HP + MHA-FA, respectively, for the experimental period [6]. Accordingly, dietary protein reduction lowered nitrogen excretion by 27% and thus increased nitrogen utilisation from about 42.6% to 47.5%.…”

“…Basically, two products for balancing dietary methionine are commercially available: DL-methionine (DLM) and liquid methionine hydroxyl analoguefree acid (MHA-FA). Research suggests that they differ in their biological activity, which is confirmed in the assessment performed by EFSA in numerous publications as 75% on an equimolar basis [6,7]. Among other causes, a lack of methionine is discussed as a predisposing factor for footpad dermatitis (FPD), hepatic lipidosis and oxidative stress [8][9][10][11].…”

“…A feed composition containing minimum protein requires a higher addition of synthetic amino acids such as Met [20]. While the biological availability of MHA-FA relative to DLM has been extensively studied in broilers, less information is available for turkeys [6,[21][22][23]. Based on their literature surveys and experiments, Hoehler and Hooge [24] and Hoehler et al [25] recommended a bioavailability of 65% for MHA-FA relative to DLM [25,26].…”