STUDIES ON THE METHIONINE REQUIREMENT OF CARP (CYPRINUS-CARPIO L.)

One hundred common carp in groups of five in four tanks/treatment were each fed five diets containing different amounts of methionine. The p rotein in the basal diet (T-I) was supplied by soya protein, gelatin a nd finely ground peas (Pisum sativum), which contained 0.49 g methioni ne/100 g dry matter (DM). Diets T-LI to T-V were supplemented with DL- methionine to 0.61, 0.79, 1.08 and 1.34 g methionine/100 g DM. The die ts also contained 0.42 g cystine/100 g DM and 40.2% crude protein in t he DM. The digestibility coefficient for the crude protein was 88%, an d the diets contained 16.9 MJ digestible energy (DE)/kg DM. The diets were fed at 1.8% of live weight and the experiment lasted for 85 days. Growth rare, feed intake, protein content of the fillet, viscera and residual carcass, and the plasma concentrations of met, arg, leu and t rp were all increased significantly by the addition of increasing diet ary methionine. The fat content of the fish and the plasma concentrati ons of lys, his, ser, pro and asn were increased in the fish fed diets deficient in methionine. A met requirement of 0.855 g/100 g DM or 2.1 3 g/100 g crude protein or 0.51 g/MJ DE was calculated using the broke n-line model based on final weight and protein deposition data. (C) 19 98 Elsevier Science B.V.