Validation into excavated earthen ponds of a finishing vegetable ration supplemented with Schizochytrium sp meal to produce DHA-rich Colossoma macropomum

Abstract

The aim of the study was to validate a DHA-rich production technology for gamitana, Colossoma macropomum, in excavated earthen ponds by supplying a finishing vegetable ration supplemented with Schizochytrium sp. meal. A vegetable ration (VR) and a vegetable ration supplemented with 5% Schizochytrium sp. meal (DS) were used. A total of 1200 fish (258.90 ± 6.93 g) were distributed in six 200 m³ earthen ponds at a density of 1 fish/m³, and fed with VR for 120 d. Then, fish from three randomly selected ponds continued to be fed VR and the remaining ones were fed DS for 71 d, the minimum period to maximize the DHA content in the gamitana fillet. The feed was provided at 08:30 and 16:30 h at a daily rate of 1.50%. Body growth, proximal content, fatty acid content and nutritional quality of the lipid fraction of the fillet, as well as pH and microbiological characteristics of the fillet were evaluated. Data were analysed by the Student t-test for independent samples (p<0.05). Microbiological evaluation data were based on the maximum permissible limit. The results of the study validated in the field a technology for natural enrichment of gamitana fillet with DHA, demonstrating that it is possible to supply vegetable ration with Schizochytrium sp. meal to gamitanas for 71 days before harvest, without affecting the growth of the fish, guaranteeing its safety (absence of microbiological contamination), without affecting the proximal content of the fillet and increasing the nutraceutical value of the fish in terms of increased DHA, n-3, PUFA content and nutritional improvement of the lipid fraction of the fish meat.