Evaluation of the productive yield and coefficient of apparent digestibility in Colossoma macropomum, of a feed formulated with Lemna minor Evaluación del rendimiento productivo y coeficiente de digestibilidad aparente en Colossoma macropomum, de un alimento formulado con Lemna minor

Abstract

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 (Cr2 O3),
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% Cr2 O3,
and the test diet (T2), composed of 71% fishmeal. of reference diet, 1.0% Cr2O3and 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.