Effects of linseed oil supplementation duration on fatty acid profile and fatty acid metabolism-related genes in the muscles of Chinese crested white ducks

Considering that dietary fatty acid composition affects the polyunsaturated fatty acids (PUFAs) profile of duck meat, the current study sought to evaluate the effects of the feeding time of a linseed oil diet on duck performance, meat quality, plasma biochemical indicators, fatty acid profile, and gene expression. Linseed oil is a rich source of n-3 PUFAs. To this end, we selected 168 28-day-old Chinese crested ducks and divided them into three groups. The control group was fed the basic diet, and the duck fat in the experimental group diet was replaced by 2% linseed oil. Ducks in the two experimental groups were fed a linseed oil diet for 28 and 14 days at 28 and 42 days of age, respectively. The results show that linseed oil does not negatively affect the production performance or meat quality of ducks (P > 0.05). Moreover, given that lipid changes in the plasma reflect the metabolic conditions of the liver, plasma parameters were also assessed. The addition of linseed oil in the diet increased the plasma total cholesterol and high-density lipoprotein cholesterol levels (P < 0.05), while decreasing the triglyceride content (P < 0.05). Four weeks of linseed oil supplementation also impacted the muscle fatty acids composition. More specifically, α-linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid levels were increased (P < 0.05), whereas the eicosatetraenoic acid content was negatively correlated with linseed oil consumption (P < 0.05). qRT-PCR analysis further revealed that the expression of FATP1, FABP5, and ELOVL5 genes in the breast muscle, and FABP3 and FADS2 genes in the thigh muscle, increased after four weeks of linseed oil supplementation (P < 0.05). However, after feeding for two weeks, CPT1A gene expression inhibited fatty acids deposition, and suggested an increase in fatty acids oxidation (P < 0.05). Thus, the enrichment of fatty acid transportation and binding proteins provided sufficient functional proteins for the intramuscular transport and transformation of α-linolenic acid. This promoted the deposition of n-3 PUFAs and provided consumers with high-quality healthy duck meat, particularly after four weeks of feeding linseed oil.