- In this review, various studies conducted on comparative bioavailability of DL-methionine and L-methionine are discussed. Results of dose response, growth performance and physiological studies proved the nutritional equivalence of DL-methionine and L-methionine in broilers.
- 100 % absorption and efficient utilization of D-isomer of methionine in poultry results in the same bioavailability of DL-methionine compared to L-methionine. Therefore, reduction in M+C level of poultry diets with L-methionine supplementation is not true.
- No difference in the amino acid profile of tissues at different supplementation levels of DL-methionine and L-methionine also indicates the similar utilization of both sources.
- Blood metabolomes of birds fed diets supplemented with DL- or L-methionine showed minor effects on their metabolism. However, low supplementation of L-methionine results in up-regulation of methionine oxidation, whereas high supplementation of L-methionine results in down-regulation of the tricarboxylic acid cycle. Further studies need to be conducted to investigate the relationship between L-methionine supplementation and up-regulation of methionine oxidation.