Evaluación del rendimiento productivo y coeficiente de digestibilidad aparente en Colossoma macropomum, de un alimento formulado con Lemna minor.

In order to identify new alternative raw materials as sources of protein for fish feed, the apparent digestibility coefficients (ADC) of the protein and dry matter of Lemna minor duckweed included in a diet for cachama negra Colossoma macropomum and the effects of the productive performance in the fry stage, calculating its weight. To estimate the coefficients, the indirect method was used with the inert marker chromic oxide (Cr2O3), collecting the feces by Siphoning. 136 fingerlings (average weight 0.4 g) were used, which were randomly distributed in the aquariums (experimental units) with a volume of 27 liters, in groups of 17 fingerlings/aquarium. Two experimental diets were evaluated: the reference diet (T1) composed of 42% fishmeal, 14% cassava, 43% soybean and 1.0% Cr2O3, and the test diet (T2), composed of 71% fishmeal. of reference diet, 1.0% Cr2O3 and 28% of the test ingredient (duckweed flour). Four replicates per diet were evaluated. Feces were collected and immediately dried and stored at 60°C and –12°C, respectively, until analyzed for proximal composition and Cr2O3 levels. The experimental phase lasted 30 days, the results of weights per replicate in the biometrics were evaluated through a descriptive statistical analysis. No statistical differences (p>0.05) were found by biometry between the treatments, even so, higher productive yields were found with T2. Survival was T1=94.12%, and T2=100%. The CDA for dry matter and protein of the raw material were 92.57±3.60 and 77.97±0.91, respectively. The inclusion of this meal in diets for cachama fingerlings is feasible in terms of growth, weight gain and reduction of feed costs, in addition, the high ADC value shows that cachama negra can digest duckweed protein. [ABSTRACT FROM AUTHOR]