Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5510479 | Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology | 2017 | 37 Pages |
Abstract
Silver barb (Puntius gonionotus) is considered a promising medium carp species for freshwater aquaculture in Asia. This study in silver barb was carried out to evaluate the effects of total or partial substitution of dietary fish oil (FO) with linseed oil (LO) on growth, nutrient utilization, whole-body composition, muscle and liver fatty acid composition. Fish (12.1 ± 0.4 g of initial body weight) were fed for 60 days with five experimental iso-proteinous, iso-lipidic and iso-caloric diets in which FO (control diet) was replaced by 33.3%, 50%, 66.7% and 100% LO. Final weight, weight gain, percent weight gain, SGR decreased linearly (p < 0.001) with increasing LO levels in the diets. Dietary LO substitution levels did not significantly (p > 0.05) affect the feed conversion ratio (FCR), protein efficiency ratio (PER) and whole body proximate composition. Furthermore, enhanced level of LO increased α-linolenic acid (ALA; 18:3n3) and linoleic acid (LA; 18:2n6) and decreased eicosapentaenoic acid (EPA; 20:5n3) and docosahexaenoic acid (DHA; 22:6n3) in muscle and liver. To understand the molecular mechanism of long chain-polyunsaturated fatty acid (LC-PUFA) biosynthesis, we cloned and characterized the fatty acyl Î6 desaturase (Î6 fad) cDNA and investigated its expression in various organs/tissues following replacement of FO with LO in the diet. The full-length Î6 fad cDNA was 2056 bp encoding 444 amino acids and was widely expressed in various organs/tissues. Replacement of FO with LO increased the expression of Î6 fad mRNA in liver, muscle and intestine but no significant difference was found in the brain.
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Authors
Madhusmita Nayak, Ashis Saha, Avinash Pradhan, Mrinal Samanta, Shiba Shankar Giri,