Abstract

SILVA-ACUNA, Annie  and  GUEVARA, Miguel. Evaluation of two commercial diest on growth of the hubryd Colossoma macropomum x Piaractus brachypomus. Zootecnia Trop. [online]. 2002, vol.20, n.4, pp.449-459. ISSN 0798-7269.

With the purpose of evaluating the influence of two types of formulated foods on fish growth for the hybrid of cachama x morocoto and the potential growth in captivity, it was carried out at Cocuina Island, Delta Amacuro State, Venezuela, an experimental sowing with 2250 fingerlings (initial average weight of 123 ± 0.9 g), obtained from the cross of a female Colossoma macropomum (cachama) x a male Piaractus brachypomus (morocoto), stocked in six earthen ponds of 750 m², with a density of 0,5 fingerlin/m². The fingerlings were placed under two treatments: T₁ (Cachama food with 28% protein content), and T₂ (Tilapia food with 24% protein content), during a period of 105 days. Fish reached a final average weight of 1.2 and 1.3 kg for T₁ and T₂, respectively with no significant differences (P>0.05). Net yield was 5.8 y 6.0 Tm/ha for T₁ y T₂, respectively, being one of the highest values reported for this lapse of time. Feed conversion and survival rate were 1.1 and 94.4% for T₁ and 1.2 y 91.6% for T₂. Absolute growth of 10.69 and 11.50 g/day were obtained with T₁ and T₂, respectively. It was evident that, starting the sowing with fingerlings of 123 g of average weight and using the formulated diets as food, it can be obtained fishes of commercial size in 105 days. This is a novel report in this type of culture, that would allow to obtain two annual crops, at least. Finally, it can be concluded that the growth in size and weight of hybrid of cachama x morocoto, in this lapse of time, is similar that using commercial diets as food with 28 or 24% protein.

Keywords : Colossoma; Piaractus; fish culture; cachama hybrid; formulated foods.