Evaluation of morhometric growth curves of tilapia of Nilo (Oreochromis niloticus) strains

The objective of this research was to evaluate the morphometric growth curves of tilapia strains in function of the body weight, an experiment was carried out at the Fish Culture of the Animal Sciences Department, Federal University of Lavras, M.G - Brazil. Three hundred sixty-two (362) fish of the Chitralada strain and three hundred forty-five (345) of the Supreme strain, weighting between 1,7 and 800 g were used. With the animals' growth, random samples were taken; the fish were slaughtered, weighted and submitted morphometric evaluation. Different models of growth of body measurements in function of the body weight were fitted. In general, the measurements were adequately adjusted. Shorts differences were found between the fit of the models for limiting values (A) and high differences for growth rate relative the maturity (K) for all the measurements. The Brody and Logistic models had higher differences than Gompertz and von Bertalanffy that stayed in intermediary position. The Supreme strain had "A" for standard length (SL) slightly higher and for body height slightly smaller than Chitralada strain. The Chitralada strain had higher "K" for head length/standard lenght relation than Supreme strain. The Gompertz, Brody, von Bertallanffy a Logistic models described adequately the morphometric growth of tilapia in function of body weight, being more indicate the models Gompertz and von Bertalanffy. The differences between Chitralada and Supreme tilapia strains were small.