Addition of Emulsifiers to Hydrogenated Soybean Oil‐Based Feeds for Yellowtail

Abstract

Hydrogenated soybean oil can be used to spare fish oil in aquafeeds, but lipid digestibility may be a limiting factor. We evaluated the performance and tissue fatty acid composition of juvenile Yellowtail Seriola dorsalis that were fed diets containing menhaden fish oil (positive control), hydrogenated soybean oil (negative control), or hydrogenated soybean oil amended with 1% mixed bile acids, casein, whey protein, or monoglycerides as emulsifying agents. Juvenile fish (~10 g) were stocked in a semi-closed recirculation aquaculture system (15 fish/tank), diets were randomly assigned to tanks in triplicate (N = 3), and fish were fed in slight excess of estimated apparent satiation amounts for 6 h/d with belt feeders. After 8 weeks, production performance was equivalent for fish fed the positive control and negative control feeds; amending the hydrogenated soybean oil-based feeds with casein, whey protein, or monoglycerides did not affect performance, whereas adding mixed bile acids significantly impaired performance (weight gain = 655-681% versus 459%; survival = 98-100% versus 49%; feed conversion ratio = 1.19-1.22 versus 1.56). Whole-body fatty acid composition tended to mirror dietary composition except that fish receiving the hydrogenated soybean oil-based feeds exhibited disproportionately lower levels of saturated fatty acids and higher levels of monounsaturated fatty acids, long-chain polyunsaturated fatty acids, and n-3 and n-6 fatty acids compared to dietary levels. Results suggest that casein, whey protein, and monoglycerides could be added to saturated fatty acid-rich hydrogenated soybean oil-based diets to reduce tissue fatty acid profile distortion, but production performance might not be enhanced. Of all the hydrogenated soybean oil-based feeds in this study, the one supplemented with casein resulted in a whole-body fatty acid profile closest to that of fish fed the fish oil-based feed. Mixed bile acids should not be added due to the resulting negative impacts on survival and growth.

Replacing Fish Oil with Hydrogenated Soybean Oils in Feeds for Yellowtail

“…Digestibility and utilization of these and other SFA‐rich lipids constitute an area of ongoing concern (Bergman et al. ); the effects of SFA‐rich lipids on tissue lipid content will also have to be considered when using LC‐PUFA sparing to enhance or maintain fillet nutritional value.…”

Effects of Dietary Lysophosphatidylcholine on Growth Performance and Lipid Metabolism of Juvenile Turbot

“…Emulsifier-like feed additives have been widely used in terrestrial animals [1][2][3][4][5][6]. In recent years, they are also being more and more frequently used in farmed fish, typically bile acids [7,8]. The positive effects of bile acids on growth and lipid metabolism of farmed fish have been reported in a number of studies [9][10][11][12][13][14][15][16][17], including a recent study of ours with a marine teleost, tiger puffer (Takifugu rubripes) [18].…”

Lecithin‐containing bioemulsifier boosts growth performance, feed digestion and absorption and immune response of adult Nile tilapia ( Oreochromis niloticus )

“…The effects of supplemental emulsifiers including lecithin, lysolecithin, bile acids and phosphatidylcholine (PC), on the growth rates, feed digestion and absorption have been tried in marine fishes (Benedito‐Palos et al, 2008; Bergman et al, 2018; Feng et al, 2017; Fountoulaki et al, 2009; Liu et al, 2002), freshwater fishes (Azarm et al, 2012; Sink & Lochmann, 2014); and shrimp (Khan et al, 2018). Results indicated that these emulsifiers can improve fish performance, feed efficiency, survival and immune response.…”