Biological Effectiveness of Methionine Hydroxy-analogue Calcium Salt in Relation to DL-Methionine in Broiler Chickens

Abstract

Two feeding trials were conducted to assess the relative bioavailability (RBV) of methionine hydroxy analogue calcium salt (MHA-Ca) in comparison to DL-methionine (DL-Met). Male Ross 308 (1-38 days) and Cobb 500 chickens (1-42 days) were used in studies 1 and 2, respectively. Experimental diets based on wheat and soybean meal or sorghum and soybean meal were fed during three phases. In both experiments graded levels of DL-Met and MHA-Ca were supplemented to Met+Cys deficient basal diets. Additionally, in experiment 1, increasing levels of a DL-Met preparation diluted with corn starch to 65% purity (DL-Met65) were supplemented. Birds were kept in floor pens and feed and water were available ad libitum. Body weights and feed consumption were recorded at the beginning and end of the experimental periods and weight gain and feed efficacy were computed subsequently. At the end of the experiments, a number of birds were slaughtered for carcass evaluation (dressing percentage, breast meat yield). Dose response data were analysed by both ANOVA and nonlinear common plateau asymptotic regression. In both experiments birds responded significantly to increasing levels of either methionine source. However, RBV of MHA-Ca compared to DL-Met was markedly (in many cases significantly) below 84%, the value which would have been expected from MHA-Ca's chemical characteristics. Excluding some extremely low RBV figures of trial 2, RBV of MHA-Ca averaged to about 63% in relation to DL-Met. In addition, supplementation of DL-Met65 allowed confirmation of nonlinear common plateau asymptotic regression to be suitable to determine RBV.

Bioavailability of methionine hydroxy analog-calcium salt relative to dl-methionine to support nitrogen retention and growth in starter pigs

“…To the best of our knowledge, there are no previous published data on the RBV of MHA-Ca and DL-Met to support N retention and performance in pigs. It has been recently reported that, on a product-toproduct basis, the RBV of MHA-Ca relative to DL-Met was 63% in broiler chickens (Elwert et al, 2008) and 66% in chicks fed Met-deficient basal diet (Dilger and Baker, 2008). These RBV values are slightly lower than the RVB value of 71% on a product-to-product basis observed in the current study.…”

“…In a recent study, Elwert et al (2008) reported that the mean RBV of MHA-Ca to DL-Met was 63% on a product-toproduct basis in broiler chickens. Likewise, Dilger and Baker (2008) reported that MHA-Ca was 65.6% as efficacious as DL-Met on a product-to-product basis in chicks.…”

“…Recently, the calcium salt of hydroxy analog of DL-methionine (MHA-Ca, 84%) was re-introduced to the market as an alternative Met source for poultry and swine in addition to DL-methionine 99%) and liquid MHA-free acid (MHA-FA, 88%) that have been utilized as Met sources during the past two decades (Elwert et al, 2008). Like MHA-FA, the re-introduction of MHA-Ca has generated questions about its relative bioavailability (RBV) compared with DL-Met as a Met source (Elwert et al, 2008).…”

“…Recently, the calcium salt of hydroxy analog of DL-methionine (MHA-Ca, 84%) was re-introduced to the market as an alternative Met source for poultry and swine in addition to DL-methionine 99%) and liquid MHA-free acid (MHA-FA, 88%) that have been utilized as Met sources during the past two decades (Elwert et al, 2008). Like MHA-FA, the re-introduction of MHA-Ca has generated questions about its relative bioavailability (RBV) compared with DL-Met as a Met source (Elwert et al, 2008). In animal nutrition, the term 'bioavailability' refers to the degree to which an ingested nutrient in a particular source is absorbed -E-mail: martin_nyachoti@umanitoba.ca in a form that is utilized for metabolic purposes by the animal (Littell et al, 1997).…”

Bioavailability of different methionine sources for broilers from 1 to 21 days old

“…There have already been many discussions concerning the relative bioavailability of methionine from different sources, as well as a considerable number of experiments comparing various sources, mainly DL-HMBA and DLM, conducted in birds (Esteve-Garcia and Llaurado, 1997;Hoehler et al, 2005a;Elwert et al, 2008). Furthermore, the correct statistical design to evaluate the bioavailability of different sources of essential nutrients has been under debate (Littell et al, 1997;Kratzer and Littell, 2006;Piepho, 2006).…”