The efficiency of washout strategy on decreasing the deposit linoleic acid of tilapia fillet and viscera

This study was designed to explore the effectiveness of washout strategy on decreasing the linoleic acid (LA) deposition in a short time frame to improve the tilapia fillet quality. Two diets of different lipid sources, soy oil diet (S) and fish oil diet (F) were formulated and employed to create three different feeding regimes. The three regimes were; feeding on S diet for six weeks (S6), feeding on F diet for six weeks (F6), and feeding on S diet for three weeks followed by F diet for another three weeks (S3F3). Tilapia with average initial weight of 71 g +/- 0.25 had been fed twice daily by hand till satiation for six days weekly. After 6 weeks, linoleic acid decreased (11.6% total fatty acid (TFA) in the fillet of tilapia fed on F6 regime compared to fish fed on S6 regime, which had a linoleic acid content of 25.9% TFA. Fish performance and feed utilization did not differ significantly among feeding regimes except for feed intake, which improved significantly for fish fed fish oil continuously (F6). The feeding regimes had no significant effect on the unsaturated fatty acids of fish viscera except for oleic acid. Higher oleic content noticed in the viscera of fish subjected to soybean oil regimes. The results showed the ability to decrease linoleic acid and the possibility to improve the quality of tilapia fillet for human using fish oil for 6 weeks before harvest. Moreover, it could be concluded that viscera from freshwater fish subjected to washout strategy before harvest can be used as a functional ingredient in aquafeed which is a step toward responsible aquaculture and sustainability.

Automated summary

This study demonstrates the effectiveness of using fish oil to decrease linoleic acid content and improve the quality of tilapia fillet. Furthermore, the washout strategy allows the use of freshwater fish viscera as a functional ingredient in aquafeed.