A combination of plant oils promotes adequate growth of the freshwater catfish Rhamdia quelen (Quoy & Gaimard 1824)

摘要

Essential fatty acids should be included in the diet to ensure adequate fish growth. Despite the great number of studies on fatty acid nutrition of fish, there are still several unknowns. The aim of the present study was to investigate fatty acid nutrition of jundia, a Latin American freshwater catfish. Four diets were formulated containing (i) coconut oil (-C, negative control), (ii) coconut oil + high-docosahexaenoic-acid-fish oil (+C, positive control) and coconut + sunflower + linseed oils at different ratios, producing either (iii) a diet rich in linoleic acid (LA) (HighLA) or 4) a diet low in LA (LowLA). All diets contained significant amounts of saturated fatty acids (at least 57.5% total fatty acids in HighLA) and monounsaturated fatty acids (at least 19.1% total fatty acids in -C). Diets were fed to jundia fingerlings (1.5g) for 70days; growth, body composition and liver histology were evaluated. The -C diet, without essential fatty acids, promoted significantly lower fish growth, body fat accumulation and hepatic lipidosis. Fish fed HighLA and LowLA diets presented similar growth as fish fed +C diet. These findings suggest that diet formulations for jundia catfish fingerlings can include only plant oils without negative effect on growth, survival, body composition, fish health or parameters of feed utilization (ingestion rate and protein utilization).