Nutritional Values Of DL-methionine Hydroxy Analogue Calcium Salt, DL-methionine And L-methionine In Broilers And Their Antioxidant Functions

In order to evaluate the nutritional value of DL-methionine in comparison with DL-methionine hydroxy analogue calcium salt(MHA-Ca) and L-methionine(L-Met) in broiler chickens, 1280 male healthy Arbor Acres broiler chickens at 10-days old with similar body weight were used for a feeding trial. All birds were randomly allocated to sixteen treatments. Each treatment consisted of eight replication pens with 10 broilers in each pen. Two corn-soybean meal-pea protein concentrate based basal diets were prepared with one as a starter(d 10-21) and another as a grower(d 21-42). These basal diets were deficient in Methionine+Cystine, without any methionine supplementation. Each basal diet was split into 16 lots. Birds of treatment 1 received the pure basal diets; and other treatments received diets supplemented with 0.03, 0.06, 0.10, 0.15 and 0.21% of DL-Met, L-Met or equal molar MHA-Ca, respectively. All feed was provided in pellet forms. An exponential regression analysis was used to determine biological efficacy based on body weight gain, feed conversion rate and carcass performance. The bio-efficacies of MHA-Ca and L-Met relative to DL-Met was 46% and 103% for daily gain; and 58% and 107% for feed conversion rate, respectively; In addition, based on breast meat yield, MHA-Ca and L-Met were 81% and 104% as efficacious as DL-Met. Considering all the values for performance carcass parameters in this study, the calculated nutritional value of L-Met and MHA-Ca in comparison to DL-Met is 105% and 48% on the equal molar basis. There was a significant difference between control group and treatments for carcass weight, breast weight, breast yield, leg weight, leg meat weight and wing weight. But no significant difference was found among different types of methionine at the same levels for carcass quality parameters. As for the redox state, all the three methionine could improve the birds redox state, and their efficacy was no different at equal added level.there was no significant difference among different supplements at equal levels, however, difference has been found in different supplement levels among three types of methionine.In conclusion, these results showed that DL-Met had the same nutritional value as L-Met,while MHA-Ca had a much lower nutritional value compared with DL-Met or L-Met in broilers for growth performance. However, all three types of methionine had same effects on antioxidant functions in broilers.