Relative bioavailability of calcium salt of DL-Methionine hydroxy analogue compared with DL-Methionine for nitrogen retention in starter pigs
Methionine (Met) is an essential amino acid (AA) that must be supplied in adequate amount in the diet to optimize animal performance. In addition to DL-Methionine (DL-Met, 99 %) and liquid Methionine hydroxy analogue-free acid (MHA-FA, 88 %), calcium salt of hydroxy analog of Met (MHA-Ca, 84 %) is recently re-introduced into the market as a Met source for poultry and swine (Elwert et al., 2008). This re-introduction has generated questions about relative bioavailability (RBV) of MHA-Ca to DL-Met as a Met source.
Most of the published studies dealing with the RBV of Met sources in pigs have been focused on the liquid MHA-FA. For example, Kim et al (2006) determined the RBV of liquid MHA-FA relative to DL-Met to be on average 66 % on a product basis based on nitrogen (N) retention (g/d) in 17-21 kg pigs. Based on the N-balance parameters, Opapeju et al. (2010) recently determined the mean RBV of MHA-Ca compared with DL-Met to be 67 % on a product basis, which suggest that the RBV of MHA-Ca is similar to that of liquid MHA-FA in pigs. However, more information about the RBV value of MHA-Ca to DL-Met in pigs is needed.
Therefore, the objective of the t study is to determine the efficacy of MHA-Ca compared with DL-Met, to support N-retention in starter pigs weighing approximately 15-18-kg body weight (BW).
The results of the study showed that the nitrogen retention did not differ among pigs fed similar inclusion levels of two Met sources added to the Met-deficient diet at a DL-Met to MHA-Ca ratio of 65:100 on a product basis. Using a slope-ratio procedure, the bioefficacy of MHA-Ca relative to DL-Met was 63 % on a product-to-product basis (75 % on equimolar basis) for N retention (g/day) when added to a Met-deficient diet.
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Article made possible through the contribution of La Van Kinh, John Htoo, Nguyen Van Phu, Doan Vinh and La Thi Thanh Huyen