Comparison of natural pond system with an intensive (indoor) system for raising Cachama (Colossoma macropomu) and Tilapia (Oreochromis niloticus)

摘要

Twosystemsoffishculture:intensiveinindoortanksandnaturalinoutdoorponds;andnbsp;twospeciesoffish:Tilapia(Oreochromisniloticus)andCachama(Colossomamacropomu)werecomparedina2*2factorialarrangementwith3replications.nbsp;Thefishintheintensivesystemwereraisedinplastictanksof0.5m3capacity(50fishpertank)andgivencommercialfishfeed(35%crudeprotein)at3-5%ofliveweight.Thepondsinthenaturalsystem(2*2*1.5m)werelinedwithpolyethylenefilmandfertilizedwithbiodigestereffluent(240mgN/m2/day);supplementationwaswithfreshduckweed(Lemnaminor)andTaroleaves(Colocaciaesculenta).nbsp;Overa60dayperiod,bothTilapiaandCachamagrewfasterinweightandlength,andinweight/lengthratio,intheintensivesystemthaninthenaturalsystem.InbothsystemstheTilapiagrewfasterthantheCachama.LesssupplementDMwasrequiredperunitliveweightgainfortheTilapiainthenaturalthanintheintensivesystem,withtheimplicationthatdespitetheslowergrowthrates,theeconomicanalysiswouldfavourtheformer.