Nutritional Characteristics of Juvenile Black Rockfish Sebastes schlegeli Fed a Diet of Fig Leaf Extract

Abstract

The present study investigated the effect of diets supplemented with different levels (0, 1, 3, and 5 %) of fig leaf ethanol extract (FLEE) on the nutritional composition of black rockfish Sebastes schlegeli. Fish (10.05 ± 0.44 g) were fed to apparent satiation twice daily for 8 weeks. Adding FLEE decreased crude lipid levels and increased crude protein and ash. Among the three organic acids in the whole body of black rockf ish, lactic acid was predominant, followed by citric acid and oxalic acid. Five free sugars were found in all groups. Fucose and glucose were the dominant free sugars in the FLEE-added group. The abundant fatty acids in the FLEE-added group were C16:0, C18:1-cis (n9), and C22:6n-3. The major amino acids in the samples were glutamic acid, aspartic acid, glycine, leucine, alanine, lysine, and arginine. The abundant free amino acids in the FLEE-added group were taurine, glutamic acid, alanine, leucine, and arginine.

Nutritional Composition Changes in Skate (Raja kenojei) during Different Ripening Periods

“…The lactic acid content of fish is low when they are promptly killed but is high after stressful or hard exercise [24]. Lactic acid was predominant, comprising approximately 90% of the total organic acid content in mackerel, pacific saury, yellow croaker, brown sole, wild and cultured red sea bream, rockfish, and flounder [23]. However, in the current study, the phosphoric acid content was the highest, followed by that of oxalic acid and lactic acid.…”

“…The oxalic acid content gradually increased until ripening day 15, but significantly decreased at ripening day 20 (p<0.05). The organic acid content of fish is known to be affected by the fishing method, amount of time since death, conditions after death, and prompt killing methods [23][24][25]. The lactic acid content of fish is low when they are promptly killed but is high after stressful or hard exercise [24].…”