Changes in fatty acids, blood biochemistry and mRNA expressions of genes involved in polyunsaturated fatty acid metabolism in brown trout (Salmo trutta) during starvation and refeeding

The present study investigated the effects of 42-day starvation followed by 14-day refeeding, on lipid metabolism in juvenile brown trout (Salmo trutta). Starvation significantly decreased plasma triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein and very low-density lipoprotein levels. The individual and total saturated and monounsaturated fatty acid levels significantly decreased throughout the treatment (except stearic acid), and whereas the individual and total polyunsaturated fatty acid (PUFA) levels significantly increased, with some exceptions, such as alpha-linolenic acid. The mRNA expressions of genes involved in the elongation, desaturation and fatty acid oxidation pathways were downregulated (except Delta 6fadc), whereas those ofppar alpha,ppar gamma andpparsswere upregulated. Our results indicated that the 14-day refeeding period was sufficient to recover the studied parameters (except growth). To date, no other study has described the effects of starvation on fatty acid metabolism, especially molecular n-3 PUFA metabolism, in brown trout. Therefore, determining the responses of fatty acid metabolism to starvation in brown trout would contribute to further studies on the starvation physiology in teleosts.