Bioavailability of liquid methionine hydroxy analogue-free acid relative to DL-methionine in broilers

An experiment with broiler chickens was conducted to compare the relative bioavailability of liquid methionine hydroxy analogue free acid (MHA-FA) with that of DL-methionine (DLM) during fattening to 35 days of age. Ross 308 male chicks were allotted to 9 treatments, each consisting of six replicates of 140 birds/pen. Four graded levels (0.04, 0.08, 0.16, and 0.28 %) of MHA-FA or DLM products (weight/weight comparison) were added to a maize-wheat-soyabean meal basal diet deficient in sulphur amino acids. The criteria of response were body weight, feed conversion ratio, carcass yield and breast meat yield. Significant responses to graded levels of both methionine sources were observed in all response criteria. Using a multi-exponential model describing the dose-response relationships, the bioavailability estimates of MHA-FA relative to DLM on a weight-to-weight basis were 68, 70, 54 and 59 % for body weight, feed conversion, carcass yield and breast meat yield, respectively. If MHA-FA was compared with DLM on equimolar basis its bioavailability was 77.7, 79.0, 59.3 and 64.6 for body weight, feed conversion, carcass yield and breast meat yield, respectively. The bioavailability of MHA-FA for carcass yield and breast meat yield was significantly (P < 0.05) lower than that of DLM on a weight-to-weight and on equimolar basis

Effects of Guanidinoacetic Acid Supplementation to Broiler Diets With Varying Energy Content

An experiment was conducted to determine the response of broiler chickens to guanidinoacetic acid (GAA) added to diets with different energy levels during fattening to 35 days of age. Ross 308 male chicks were allotted to 10 treatments, each consisting of six replicates of 140 birds/pen. Five maize-soyabean meal isonitrogenous diets with decreasing AMEn levels (100, 99, 98, 97 and 96% of requirement) with or without supplements of 0.6 g/kg CreAMINO® containing a minimum of 96% GAA were formulated. The criteria of response were feed intake, body weight gains, feed conversion ratio and carcass, breast meat, leg meat and abdominal fat yields. Supplementation of broiler diets with 0.06% GAA resulted in a significant (P < 0.05) decrease in voluntary feed intake. With decreasing AMEn level, voluntary feed intake and consequently protein and amino acid intakes increased which was manifested by improved growth performance (P < 0.01). GAA supplements significantly (P < 0.001) improved feed conversion ratio and efficiency of AMEn utilization and significantly (P < 0.01) increased breast meat yield. With decreasing AMEn level, the effects of GAA supplementation tended to diminish