Reproductive performance in male European sea bass (Dicentrarchus labrax, L.) fed two PUFA-enriched experimental diets: a comparison with males fed awet diet

Reproductive performance of male European sea bass (Dicentrarchus labrax) f ed a wet diet (WD) was compared to that of fish fed two commercial pelleted diet enriched with polyunsaturated fatty acids (PUFAs) by the use of North ern hemisphere fish oil (ST) or tuna orbital oil (RO). Broodstock growth, s permiation duration, milt production, milt spermatozoa density, sperm motil ity, milt lipid composition, and fertilization rates were compared during t he reproductive season. RO and ST males exhibited longer spermiation periods producing statisticall y higher milt volumes and milt spermatozoa densities as compared to WD; no differences in quality or motility of sperm were observed between groups. A lthough the fertilization rates of RO, ST and WD milt at 3 and 24 h after f ertilization were similar (88-90%), significantly higher rates of embryonic and larval survival were observed at 48 and 72 h after fertilization from eggs fertilized with ST (13.9% and 15.5%) and RO milt (20.9% and 20.6%) as compared to WD (1.0% and 1.2%). Analysis of milt PUFA profiles revealed sev eral differences between groups. Although total PUFAs wereincreased in all groups as compared to diet PUFA composition, a greater increase was noted f or ST and RO. In January and March, fish fed the WD exhibited more weight g ain and attained significantly higher weights, respectively, than RO fish. Results showed that although fish fed the WD displayed increased weight gai n, reproductive performance was enhanced in males fed the commercially fabr icated diets possibly reflecting benefits of PUFA-enrichment. (C) 2001 Else vier Science B.V. All rights reserved.