Growth Performance and Tissue Fatty Acid Composition of Rainbow Trout Reared on Feeds Containing Fish Oil or Equal Blends of Fish Oil and Traditional or Novel Alternative Lipids

Abstract

Fish oil (FO) sparing is common in aquafeed formulation; however, some alternative lipids have proven to be more successful than others in ensuring adequate growth and maintenance of desirable fillet fatty acid (FA) composition. Depending on the lipids used, grow‐out feeds influence the FA composition of the tissues of “lean‐fleshed” fishes and their responsiveness to subsequent tailoring during finishing. To address whether different lipid sources similarly influence growth performance and tissue composition of a “fat‐fleshed” fish, rainbow trout Oncorhynchus mykiss were reared on feeds containing FO or a 50:50 blend of FO and coconut oil (COCONUT), palm oil (PALM), standard soybean oil (STD‐SBO), hydrogenated soybean oil (HYD‐SBO), low‐18:3(n‐3) (alpha‐linolenic acid) soybean oil (LO‐ALA‐SBO), or low‐18:3(n‐3) canola oil (LO‐ALA‐CAN). Two saturated FA (SFA)‐enriched lipids derived from the processing of cottonseed (SFA‐COT) or soybean (SFA‐SBO) were also evaluated as 50% FO substitutes. After 7 weeks, growth performance was largely unaffected by dietary lipid source. Fillet levels of long‐chain (LC) polyunsaturated FAs (PUFAs) among fish that received the HYD‐SBO, LO‐ALA‐SBO, SFA‐SBO, and SFA‐COT feeds were equivalent to levels in fish that received the FO feed, despite an approximate 50% reduction in dietary LC‐PUFA intake. Our results indicate that feeds containing a blend of FO and novel soy‐ or cottonseed‐derived lipids yielded equivalent growth performance and fillet LC‐PUFA content in rainbow trout. The use of STD‐SBO, COCONUT, PALM, or LO‐ALA‐CAN did not impair growth or efficiency but did alter the fillet FA profile. Rainbow trout appeared to differ somewhat from other fishes in terms of dietary influence on tissue FA profile; however, the pattern of greater LC‐PUFA retention in fish reared on SFA‐rich feeds appears to be largely consistent among the fish taxa we have assessed.Received January 19, 2010; accepted July 25, 2010

More Judicious Use of Fish Oil in Cobia Feeds: II. Effects of Graded Fish Oil Sparing and Finishing

“…Fish oil sparing rarely impacts fish production performance as long as essential fatty acid requirements are met (Turchini et al , 2011aGao et al 2011;Trushenski et al 2011aTrushenski et al , 2011bTrushenski et al , 2011cTrushenski et al , 2011dTrushenski et al , 2013aTrushenski et al , 2013bKamarudin et al 2012;Mulligan and Trushenski 2013;Ng et al 2013;Trushenski and Kanczuzewski 2013). Our results are consistent with this convention and with other research on fish oil sparing in Cobias (Trushenski et al 2011a(Trushenski et al , 2012(Trushenski et al , 2013bWoitel et al 2014).…”

“…Specifically, differences in fillet LC-PUFA content persisted through harvest, and there was no significant effect of time (i.e., the duration of finishing) on fillet LC-PUFA level; in addition, C 18 PUFA levels increased significantly in all fillet and eye tissues and in some liver tissues during finishing. It has been suggested that C 18 PUFAs are somewhat resistant to change during finishing (Thanuthong et al 2011;Trushenski et al 2011b), but we believe that in the present case these trends are more likely related to differences in fatty acid composition among different batches of finishing feed (Table 3). Batches of the finishing feed were assembled independently and at disparate times.…”

Effects of Fish Oil Sparing on Fillet Fatty Acid Composition in Hybrid Striped Bass Are Influenced by Dietary Levels of Saturated and Unsaturated Fatty Acids

“…For example, in Rainbow Trout Oncorhynchus mykiss, feeding diets containing 50:50 blends of fish oil and beef tallow, pork lard, poultry fat, fully or partially hydrogenated soybean oil, fully hydrogenated cottonseed oil, palm oil, or coconut oil resulted in fillet D jh values of approximately 4-11, whereas feeding 50:50 blends of fish oil and soybean or canola oils resulted in D jh values of approximately 14-17 (Trushenski et al 2011a(Trushenski et al , 2011c. A review of the literature on fish oil sparing in Rainbow Trout indicated similar, high D jh values for fish fed blends of other C 18 PUFA-rich vegetable oils, including sunflower and soybean oils (Gause and Trushenski 2013).…”

“…To increase shelf stability or alter the physical characteristics of soybean oil, it is common for it to be partially or fully hydrogenated to decrease C 18 PUFA levels. The hydrogenation process increases MUFA and SFA content, and hydrogenated soybean oils have shown promise as tissue profile-conserving alternatives to fish oil in aquafeeds (Laporte and Trushenski 2011;Trushenski et al 2011aTrushenski et al , 2013aMulligan and Trushenski 2013;Woitel et al 2014a). More recently, hydrogenation has fallen out of favor as health and nutrition professionals and the general public have become aware of the hazards of trans fats generated by the hydrogenation process (Brown and Hart 2011).…”

“…It is well established that feeds reduced in or free of fish oil are typically well accepted and utilized, so long as essential fatty acid requirements are met; it is equally well established that these dietary manipulations affect the fatty acid composition of the resulting fillets, causing them to contain lower levels of beneficial LCPUFAs (Glencross and Turchini 2011;Trushenski and Bowzer 2012;Pérez-Sánchez et al 2013). Alternative lipids containing reduced levels of C 18 polyunsaturated fatty acids (C 18 PUFAs) may not affect the composition of fish tissues to the extent that C 18 PUFA-rich lipids do (Laporte and Trushenski 2011;Trushenski et al 2011aTrushenski et al , 2011bTrushenski et al , 2011cTrushenski et al , 2011dTrushenski et al , 2013aTrushenski et al , 2013bTurchini et al 2011;Ramezani-Fard et al 2012;Trushenski and Kanczuzewski 2013;Woitel et al 2014aWoitel et al , 2014bTrushenski and Bergman 2014). Of the various lipids with potential "omega-3 sparing effect[s]" , saturated fatty acid (SFA)-rich lipids appear to be the most successful in terms of preserving tissue composition (Trushenski et al 2008(Trushenski et al , 2011aTrushenski and Kanczuzewski 2013;Woitel et al 2014a); however, SFA-rich lipids may not be well digested by all taxa or under all circumstances (Hua and Bureau 2009;Kanczuzewski and Trushenski 2015;Trushenski and Bergman FATTY ACIDS IN HYBRID STRIPED BASS FEEDS 161 2014).…”