Effect of Short‐Term Holding without Feeding after Capture on Reduction in Oxidative Stress and Maintenance of Lipid and Amino Acid Contents in Decapterus maraudsi

Abstract

Changes in hydroxyl lipids (L‐OHs; a stress level indicator), body weight, triglycerides, fatty acids, and free amino acids (FAAs) were investigated in Decapterus maraudsi caught by purse seine from two different ocean regions near Japan to determine the effect of short‐term holding without feeding on the reduction in oxidative stress. In experiment 1, the L‐OHs in the dorsal muscle significantly decreased by 9 d, whereas those in the liver decreased significantly by the end of the 33‐d holding period. The body weight, lipid content, and triglyceride composition did not change significantly for 9 d and then decreased significantly by 33 d. Fatty acid composition of the dorsal muscle and liver did not change significantly within the holding period. The FAA content in the dorsal muscle did not change until 9 d and then decreased by 33 d. In experiment 2, the L‐OHs in the dorsal muscle had significantly increased at 33 d, whereas the levels in the liver of the fish after transport to port were twice as high as those in the fish that had just been caught, but then they decreased significantly by the end of the holding period. The change in body weight, lipid content, and triglyceride composition were the same as in experiment 1. The fatty acid compositions changed at 33 d, and the total FAA content did not change until 20 d and then decreased at 33 d. Both results suggest that to avoid stress and to obtain a higher quality fish product, fish captured by purse seine should be held without feeding for 8–9 d rather than immediately shipped after capture. The results of this study may be useful for improving the quality and commodity value of fish captured in commercial fisheries, such as by purse seine, and those held in aquaculture operations, such as in sea cages.

Accumulation of Hydroxyl Lipids and 4‐Hydroxy‐2‐Hexenal in Live Fish Infected with Fish Diseases

“…And L-OH levels were higher in the order of liver, red muscle, and white muscle, based on activity in these tissues, and those of cultured fish were significantly higher than those of wild fish, reflecting the degree of oxidative stress [15]. We also verified L-OH accumulation in various diseased [15], exercise-stressed [13], purse seine experience stressed [52], transportation stressed fish [52]. For these reasons, the L-OH level is estimated to be superior to the L-OOH level as an index of peroxidative conditions in live fish.…”