The present study was conducted to evaluate different protein sources in practical diets for South American catfish fingerlings (Rhamdia quelen). Two experiments, lasting 42 days each one, were carried out by using 320 fishes with initial average weight of 1.18 <FONT FACE=Symbol>±</font> 0.28grams and 4.00 ± 0.18 grams, respectively, distributed into 16 experimental units in a water recirculating system, where each experiment was tested with four treatments and four replications. In the first experiment, four isoproteic (34% crude protein) and isocaloric (3,500 Kca<img src="http:/img/fbpe/cr/v32n3/a21img01.gif" align="absmiddle">/kg digestible energy) diets were tested. Diet A1 contained sugar cane yeast, soybean meal, and meat and bone meal, while in the other diets (A2, A3 e A4) one of those sources was suppressed. Diet A2 (sugar cane yeast and soybean meal) promoted the highest weight gain (P<0.01). The protein sources from diet A2 were used in a second experiment, where the effect of replacing sugar cane yeast with soybean meal at growing levels (75%, 87.5% e 100%) was tested on a diet (B1) containing the same levels of inclusion of both sources (36.4 %). Diet B1 provided better growth and daily weight gain in this second feeding trial (P<0.01).
Rhamdia quelen; fingerlings; feeding; protein sources
