[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to investigate the effect of freshwater rearing on the fatty acid profiles of the whole body
and muscle tissue of the European sea bass (Dicentrarchus labrax). Half of initial fish were gradually acclimated to freshwater (FW) kept at the same temperature to salt water and grown
in same conditions as their counterparts in saltwater (SW). The decrease in salinity caused an increase in the percentages
of 18:1n−9, 24:1n−9, 18:3n−3, 18:2n−6 and decrease in the percentages of 14:0, 15:0, 20:0, 21:0, 20:5n−3 and 22:6n−3 both in the whole body and in the muscle tissue fatty acid profiles. The lipids of FW-reared fish contained significantly
(P<0.01) higher percentages of 18:2n−6 and 18:3n−6 than that of SW-reared fish. However, percentages of 20:5n−3 and 22:6n−3 fatty acids decreased significantly (P<0.05) compared with those of salt water-reared European sea bass. There was a clear trend of decrement in the percentages
of n−3 PUFA fatty acids due to the decrease in water salinity. However, the percentages of n−6 PUFA fatty acids were also increased with the decrease in water salinity. We concluded that the FW acclimation is followed
by changes in certain lipid classes of sea bass muscle tissue and whole body samples. n−3/n−6 PUFA ratios were characteristic to previously reported ratios for both FW- and SW-reared European sea bass. In addition,
EPA/DHA ratios were basically similar for the fish reared in both SW and FW indicating the equal nutritional value of the
final products in terms of providing PUFA’s for human nutrition.
KeywordsFatty acids–Freshwater rearing–European sea bass–
Aquaculture International 02/2011; 19(1):51-61. DOI:10.1007/s10499-010-9340-9 · 0.98 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was conducted to evaluate the effects of diets including 0, 5, 10, 15, 25, and 40% alfalfa meals (containing 0, 20, 40, 60, 100, and 160 mg total carotenoids/kg diet, respectively) and 60 mg apo-ester, a synthetic carotenoid/kg diet on skin pigmentation, growth, feed utilization and survival of a red variety of goldfish, Carassius auratus, with average initial weight of 10.3 g, for a rearing period of 60 days. The pigmentation degree in skin of goldfish increased significantly with increasing inclusion of alfalfa up to 25% level in the diet (P < 0.05). However, the alfalfa inclusion over that level did not lead to more total carotenoid accumulation in the skin of fish. The diets including apo-ester and 15% alfalfa, both of which contained 60 mg carotenoid/kg diet, had similar effects on total carotenoid deposition in the skin of fish. Alfalfa addition of 25% or higher in the diet had an adverse effect on growth of fish compared to the control group (P < 0.05). A similar phenomenon was observed in feed conversion ratio but at the 40% alfalfa inclusion level (P < 0.05). However, no significant difference was observed in the survival of the fish. The present results demonstrate that alfalfa can be successfully used as an alternative natural carotenoid source to the synthetic apo-ester in goldfish diets. Our data indicates that 15% is a suitable dietary level of alfalfa to ensure good pigmentation, acceptable growth and feed utilization in goldfish.