Fish oil–based finishing diets strongly increase long‐chain polyunsaturated fatty acid concentrations in farm‐raised common carp ( C yprinus carpio L.)

Abstract

This study investigated effects of linseed or fish oilenriched finishing diets on the polyunsaturated fatty acids (PUFA) composition in dorsal muscle tissues of pond-cultured common carp (Cyprinus carpio). After 180 days of dietary exposure to cereal diet containing vegetable oil (1%), carp were exposed to 7% linseed (LO) or 7% fish oil-enriched (FO) finishing diets for 30 days. FO supplied 17 and 20 mg fish À1 day À1, respectively, of the long-chain n-3 fatty acids eicosapentaenoic and docosahexaenoic acid for 30 days and doubled long-chain PUFA concentrations in carp of the FO pond. The increased supply of short-chain PUFA in LO resulted in higher short chain, but not long-chain PUFA, showing that there was very little PUFA conversion. Thus, dietary short-chain PUFA could not compensate for the low levels of dietary long-chain PUFA in LO. However, moderate supply of dietary long-chain PUFA in finishing diets for 30 days is very efficient in increasing nutritionally important long-chain PUFA concentrations in carp.

Dietary Fatty‐Acid Compositions Are more Strongly Reflected in Fatty than Lean Dorsal Fillets of Common Carp (Cyprinus carpioL.)

“…Assuming that fish muscle tissues contain ~80% water, this study also indicates that the level of FA similarity between dietary supply and fish is already very high once total lipids exceed ~2% (wet weight), which is typical for dorsal fillets of carp (Böhm et al, ) and other fish species (Olsen, ). Moreover, these results provide further explanatory power to a recent short‐term feeding study, in which carp with only 4% total lipids (dry weight) strongly bioaccumulated n‐3 PUFA supplied for only 30 days (Schultz et al, ). From an applied point of view, these current results suggest that future aquaculture fish feeds may be tailored to keep carp and also other fish lean during their grow out phases in an effort to reduce the use of fish meal and oils.…”

“…From an applied point of view, these current results suggest that future aquaculture fish feeds may be tailored to keep carp and also other fish lean during their grow out phases in an effort to reduce the use of fish meal and oils. However, after grow out, such lean farmed fish become highly responsive to high‐quality feeds that contain elevated contents of particularly n‐3 PUFA supplied for a short period of time (Schultz et al, ).…”

“…If feeds are based on VO that contain relatively high n‐6 PUFA, but low n‐3 PUFA, fatty dorsal fillets of common carp or perhaps fatty fish tissues in general will track their dietary lipid profiles. From a human nutrition perspective, these results suggest that a finishing diet particularly rich in n‐3 PUFA contents will directly and positively affect the accumulation of these dietary n‐3 PUFA in lean fish (Schultz et al, ), whereas feeding n‐3 PUFA to already fatty fish, such as salmonid species, will not equally translate into higher n‐3 PUFA retention. In addition to this study that enabled us assessing how carp developed under natural pond conditions, further controlled feeding trials are required to enhance our understanding of lipids and FA retention in other freshwater fish.…”

“…However, it was shown that manipulation by supplementary diets can also positively affect feeding behavior, somatic growth, total lipid contents, and subsequently fatty acid (FA) profiles in farm‐raised freshwater fish (Schultz et al, ; Steffens, ; Vacha et al, ). In particular, common carp ( Cyprinus carpio ) could almost triple its n‐3 PUFA content after being supplied with a finishing diet containing FO for only 30 days (Schultz et al, ). It is thus evident that the dietary FA composition affects the FA composition in fish (Steffens and Wirth, ; Trenzado et al, ; Vacha et al, ).…”

Improvement of nutritional quality of cultured sobaity sea bream, Sparidentex hasta (Valenciennes) muscle by preharvest feeding of finisher feeds

“…However, supply of finisher diets lasted between 5 and 24 weeks and the supplementation of FA recovery was about 80% of n‐3 PUFA when compared to fish oil supplemented throughout the grow‐out period. But other studies with European sea bass (Montero, Robaina, Caballero, Gines, & Izquierdo, ), red sea bream (Glencross, Hawkins, & Curnow, ), gilthead bream (Fountoulaki et al, ), rohu (Karanth, Sharma, Pal, & Venkateshwarlu, ), and common carp (Schultz, Koussoroplis, Magrhoor, Watzke, & Kainz, ) showed that moderate supply of dietary n‐3 LC‐PUFA in finisher diet was very efficient in increasing the muscle n‐3 LC‐PUFA concentrations. Now‐a‐days most of the feed companies use alternative sources of protein and lipid, which ultimately reduces the quality of the cultured fish.…”