Effects of dietary sunflower oil on growth parameters, fatty acid profiles and expression of genes regulating growth and metabolism in the pejerrey (Odontesthes bonariensis) fry

Aquaculture fish diets usually contain an addition of fish oil to improve their nutritional value. The effect of the replacement of dietary fish oil (FO) by sunflower oil (SfO) on growth, fatty acid composition and expression of genes implicated in somatic growth, feed intake and fatty acid metabolism was studied in pejerrey fry. Fry were fed per 45days with diets containing FO/SfO ratios of 100% FO; 50% FO:50% SfO; 20% FO:80% SfO; and 100% SfO. No differences were detected in growth and in the total per cent of saturated and monounsaturated fatty acids. Gh, ghr-I and ghr-II showed a higher mRNA expression in head and trunk of fry fed with 100% SfO diet. Expression of igf-II was higher in trunk of fry fed with 100% SfO diet compared with 100% FO diet. The 6-desaturase gene expression was upregulated in head and trunk of fry fed with 100% SfO diet. The nucb2/nesfatin-1 gene expression decreased in the trunk of fry with increasing dietary SfO. We conclude that the replacement of fish oil by sunflower oil in pejerrey fry feed does not affect growth and is a viable strategy to reduce production costs of this fish.