Reproduction of Hatchery-Reared Pike-Perch (Sander lucioperca) Fed Diet with Low-Marine-Ingredients: Role of Dietary Fatty Acids

Abstract

This research aimed to evaluate the reproductive potential of hatchery-reared (F1) pike-perch (Sander lucioperca) broodstock fed a commercial diet with low levels of long-chain polyunsaturated fatty acids (Lc-PUFA) and wild (F0) pike-perch broodstock fed forage fish. Reproductive parameters, including pseudogonadosomatic index (PGSI), egg size, latency time, hatching rate, embryo survival, and eggs’ fatty acid (FA) composition, as well as plasma sex hormone, glucose and immunoglobulin levels after hormone injection, were analyzed. The results showed low PGSI (10% in F1 vs. 14% in F0) and embryo survival (24% in F1 vs. 61% in F0) in F1 broodstock, but a satisfactory hatching rate (63% in F1 vs. 78% in F0) and larval size (4.6 mm in F1 vs. 4.7 mm in F0). A low arachidonic acid (ARA) percentage in F1 fish eggs (1.32%), along with increased immunoglobulin levels (17.31 g/L), suggests that immune system activation might have depleted the reserves of ARA in F1 fish, which is the key fatty acid for successful oocyte maturation. We assumed that the administration of more sustainable diets, based on terrestrial plant ingredients, is not inferior to higher-quality diets based on marine ingredients.

Evaluation of Post-Larval Diets for Indoor Weaned Largemouth Bass (Micropterus salmoides)

“…This is because the results on the ARA role in skeleton growth are somewhat contradictory, given the important role of the ARA metabolite, prostaglandin E2 (PGE2), in skeleton remodeling [34,35]. Furthermore, LA, along with oleic acid (OA), which was similarly increased in EF, can inhibit the synthesis of ARA when in excess [36]. Additional research in this direction would be needed to delineate the exact amounts of LA, OA, ALA, and HUFA in the diet to support the development of the skeleton of post-larval LMB.…”

“…Feeding treatments were assigned randomly to each tank. Each tank received 6 g of feed per tank during the first two days (33,34 DPH), then four days (35,36,37, and 38 DPH), 8 g per tank, and then, for the last two days (39 and 40 DPH), 9 g per tank. In the first three days, fish received a 50:50 mixture of the weaning diet, B2 and the respective treatment diet, while from the 4th day until the end of the trial, only the trial feed was supplied to the fish.…”