Using Glycerol to Produce European Sea Bass Feed With Oleaginous Microbial Biomass: Effects on Growth Performance, Filet Fatty Acid Profile, and FADS2 Gene Expression

Using a circular economy concept, the present study investigated use of crude glycerol, primary by-product biodiesel production, as low-priced nutrient source for heterotrophic cultivation fungus-like protist Schizochytrium limacinum SR21 strain. The whole biomass this oleaginous microorganism, rich in docosahexaenoic acid (DHA) and high-quality proteins, was then paired with vegetable oil (VO) used to replace fish (FO) European sea bass ( Dicentrarchus labrax ) feeds. Four nutritionally balanced diets were formulated: diet FO (a FO-based diet), VO + 0 VO-based without S. ), 5 10 that feeds supplemented 10% , respectively. After 3-month feeding trial, all dietary groups tripled their initial weight, but growth efficiencies D. not significantly different among treatments. Although formulated polyunsaturated fatty acids (PUFAs), fed containing either or plus had higher levels PUFAs flesh than diet. Values health-related lipid indexes, such atherogenicity index, thrombogenicity quality well n-6/n-3 PUFAs/SFAs ratios confirmed high nutritional value filet, thus representing healthy product human consumption. ratio showed those diet, suggesting better filet quality, clearly indicated group best (value 0.55) second 0.98). We also evaluated regulation ?6-desaturase (or fads2 gene expression liver. highest number mRNA copies lowest. Our adds growing body literature concerning thraustochytrid valid alternative marine-derived raw materials