Marine Fish Oil Replacement with Lard or Basa Fish (Pangasius bocourti) Offal Oil in the Diet of Tiger Puffer (Takifugu rubripes): Effects on Growth Performance, Body Composition, and Flesh Quality.

Simple Summary: With the rapid development of aquaculture, searching for alternative lipid sources to fish oil has become an important task for the aqua-feed industry. Lard is regarded as a valuable alternative lipid source. Basa fish (Pangasius bocourti) offal oil also has a large annual production and high potential to be used in fish feeds. Evaluation of the efficacy of lard and Basa fish offal oil in fish feeds will provide useful information for their application in aquaculture. Both lard and Basa fish offal oil have high levels of saturated fatty acids and monounsaturated fatty acids. The "n-3 LC-PUFA sparing effects" of saturated fatty acids and monounsaturated fatty acids in fish feeds have been observed in many fish species. The present study was also aimed at validating the "n-3 LC-PUFA sparing effects" of saturated fatty acids and monounsaturated fatty acids in lard and Basa fish offal oil. Moreover, the effects of dietary lard and Basa fish offal oil on fish body composition and muscle quality were also evaluated. Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360–398%), feed intake (2.37–3.04%), feed conversion ratio (0.84–1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds. [ABSTRACT FROM AUTHOR]