Growth performance and feed utilization response of Oreochromis niloticus x Oreochromis aureus hybrids to L-carnitine measured over a full fattening cycle under commercial conditions

The response of tilapia hybrids to supplemental dietary L-carnitine with respect to growth performance and economically important efficiency parameters during a full fattening cycle was investigated. One group was fed the control diet which contained 21 mg biogenic L-carnitine/kg diet while two other groups received feed supplemented with 150 and 300 mg L-carnitine/kg diet, respectively. L-Carnitine increased tilapia growth (P > 0.05), feed conversion (P < 0.05) and protein efficiency ratio (P < 0.05) and did not alter whole body, protein and lipid composition which were about the same at the end of the feeding period for all treatments. The results indicate that, in tilapia on commercial fattening diets low in L-carnitine, supplementation of 150 mg/kg feed is effective but not the next higher supplementation level (300 mg/kg). Explanations for the positive effects are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.