Dietary ARA Improves COX Activity in Broodstock and Offspring Survival Fitness of a Model Organism (Medaka Oryzias latipes)

SIMPLE SUMMARY: The impact of arachidonic acid in broodstock diets on cyclooxygenase activity and quality of offspring was investigated on model fish species. The results have shown that arachidonic acid in the broodstock diet improves sperm motility parameters. The cyclooxygenase activity in the liver of females increased with the amounts of arachidonic acid in diets. The arachidonic acid bioconversion activity during the reproductive season via cyclooxygenase activity is involved in female fertility and embryo and larval survival and growth. ABSTRACT: A 3-week feeding trial was conducted in medaka broodstock (age five months) to examine the effect of dietary arachidonic acid (ARA) level (range: 4–23 mg g(−1) of total fatty acids (TFAs)) on fertility, cyclooxygenase (COX) activity, egg size, sperm motility parameters, hatching rate and weight of hatch, survival and growth of larvae. After spawn induction and dietary exposure to 4 mg ARA g(−1) TFA, broodstock were fed a diet containing ARA in the amounts: 4 (continued, as control), 5, 14 and 23 mg g(−1) TFA. COX1 activity in the liver and the number of COX2-positive cells in the ovaries was increased in females fed the diets containing the two highest amounts of ARA. The highest sperm motility parameters were observed in males fed a diet containing 23 mg ARA g(−1) TFA. The hatchability rate and bodyweight of hatchlings were higher in the group obtained from broodstock fed a diet containing 23 mg ARA g(−1) TFA (79% and 0.66 mg fish(−1), respectively) compared with 4 mg ARA g(−1) TFA (50% and 0.40 mg fish(−1)). The average mortality of offspring obtained from this group at 7 days post hatching was significantly higher than that of all other groups.