Shark liver and flaxseed oils as alternatives to soybean oil in the lipid quality of Japanese quail eggs

PurposeThe objective of this study was to assess the incorporation of polyunsaturated omega 3 and omega 6 fatty acids in the eggs of Japanese quails (Coturnix coturnix japonica) fed with soybean, flaxseed and shark liver oils, as well as to assess their effects on the chemical composition and lipid quality of the yolks.Design/methodology/approachThe total of 252 units of quails were distributed in a completely randomized design with seven treatments and six replications, totaling 42 experimental design units. The sources of oils and their inclusions in the experimental diet were 2% of soybean oil (S), 2% of flaxseed oil (L) and 2% shark liver oil (T), obtained from the species Carcharhinus acronotus, and the mixtures of 1% S + 1% L (SL); 1% S + 1% T (ST); 1% L + 1% T (LT) and 0.67% S + 0.67% L + 0.67% T (SLT).FindingsThe proximate composition of the egg yolk was not changed to the supplementation of lipid sources added in quail diet. The total replacement of soybean oil by shark liver oil reduced the cholesterol content in the yolk by 19% (T = 282.97 mg cholesterol/100 g egg) and the addition of flaxseed oil produced eggs with greater amount of polyunsaturated fatty acids (PUFAs) (LS = 18.32%). The treatments with flaxseed oil and its mixtures (soybean oil + flaxseed oil and flaxseed oil + shark liver oil) effectively contributed to reducing the ω-6:ω-3 ratio and enriching the quail eggs with PUFAs, especially linolenic acid (18: 3n3c) and EPA (20: 5n3c).Originality/valueThus, manipulation in the diet of quails enriched the content of essential PUFAs and reduced the cholesterol content in the yolk. The flaxseed oil was the lipid source that influenced to improve the quality of the egg yolk. These results have practical applicability for the quail egg industry.