Caracterização físico-química do oléo de coco babaçu industrial e artesanal e suas aplicações tecnológicas Physical and chemical characterization of industrial and handicraft coconut babaçu oléo and its technological applications

The meagre (Argyrosomus regius) is taking on increasing importance in the aquaculture industry. In view of the limited supply of fish oil (FO) as a feed ingredient, the study of the capacity to biosynthesize long-chain polyunsaturated fatty acids (LC-PUFA) from alternative dietary oil sources is important. We analyzed changes in fatty acid (FA) desaturase 2 (fads2) and FA elongase 5 (elovl5) mRNA levels in livers and brains in response to FO replacement with a blend of vegetable oils (VO) and selenium (Se) supplementation. Fish were fed for 60 days with either a diet containing FO or a diet including VO, each supplemented or not with organic Se. Results showed that fads2 and elovl5 transcription was higher in liver when fish were fed VO diets. The brain mRNA levels of both genes were not affected by the dietary replacement of FO by VO. FA composition in the liver and skeletal muscle was altered by FO replacement, particularly by decreasing eicosapentaenoic acid and docosahexaenoic acid contents. The α-linolenic, linoleic, and arachidonic acid contents increased in both liver and brain of fish fed VO diets. The effect of Se supplementation on lipid metabolism was evident only in fish fed FO, showing a decrease in the transcription of hepatic fads2. Results indicate that the total replacement of FO by VO in diets modulates the expression of genes involved in LC-PUFA biosynthesis in meagre, affecting the FA profile of the fish flesh.

This study aimed to evaluate changes in body composition, specially muscle and liver fatty acid profile in meagre (Argyrosomus regius) fed with different dietary lipid sources and levels, with or without selenium supplementation. Six hundred meagre were fed twice a day, 6 days per week, with eight experimental diets for 60 days. Diets were a combination of fish oil or a vegetable blend (45% linseed + 35% rapeseed + 20% soybean oil), at 12 or 17% of oil and 0 or 1 mg/kg of organic selenium, in a 2 × 2 × 2 factorial design. The whole body protein and lipid content were affected by the dietary oil source. Fish oil diets increased long‐chain (LC) PUFAs content in the edible tissues, while vegetable oil‐based diets increased short‐chain (SC) PUFAs. Vegetable oil diet tended to decrease the fish protein content. A higher lipid liver content was observed in meagre fed the vegetable oil blend. The results also suggested the ability of meagre to convert SC‐PUFA to LC‐PUFA when the vegetable oil is included in their diet. The possibility for partial substitution of fish oil by vegetable oil in meagre diets, resulting in lower dependence of fish oil in meagre farming, is also demonstrated here. Practical applications: The growing importance of aquaculture for basic food supply, and the urge for cost‐effective and sustainable feeds that maintain or even increase fish quality, makes the search for alternatives to common feeds a route of upmost importance, as the vegetable oil here addressed. SC‐PUFA and LC‐PUFA contents of the studied tissues increased with diets supplemented with 17% oil level, which may ultimately add more value to this farmed species. These results indicate the possibility of the partial substitution of fish oil by vegetable oil in meagre diets, resulting in lower dependence on fish oil for fish farming. Meagre were fed with different dietary lipid sources and levels, with or without selenium supplementation, in a total of eight experimental diets during 60 days, in a 2 × 2 × 2 factorial design. Fish oil diet increases HUFAs and vegetable oil diet increases PUFAs in body composition. There is great potential for partial substitution of fish oil by vegetable oil in meagre (Argyrosomus regius) diets, resulting in lower dependence of fish oil in meagre farming.