Long-term alternate feeding between fish oil- and terrestrially sourced oil-based diets mitigated the adverse effects of terrestrially sourced oils on turbot fillet quality

Abstract

Use of terrestrially sourced oil (TSO) in fish diets easily causes adverse effects on fillet quality. The present study, with turbot, was aimed at evaluating the efficacy of alternate feeding between fish oil (FO)- and TSO-based diets in minimizing these adverse effects. The control group were fed the FO-based diet continuously for 13 weeks, meanwhile other groups were subjected to weekly alternation between the FO-based diet and diets based on TSO, namely, linseed oil, soybean oil, rapeseed oil, palm oil, and beef tallow, respectively. The feeding trial was conducted in a flow-through seawater system. Each group had triplicate tanks, and each tank was stocked with 35 fish. Samples were collected at the end of Week 9 and 13. At Week 9, no significant difference among groups was observed in growth performance and muscle proximate composition, texture, and odour-active compound profile; however significant differences were observed in muscle content of long-chain polyunsaturated fatty acids, serum malondialdehyde content, and somatic indices. These differences disappeared at Week 13. In conclusion, long-term alternation between FO- and TSO-based diets could mitigate the adverse effects of TSO on farmed turbot.