Rainbow trout neomales broodstocks are able to eat and use a high carbohydrate diet during a complete reproductive cycle

Abstract

The main challenge of the aquaculture relies on the shift from fishmeal to more sustainable ingredients. Interest on carbohydrates has growing rapidly as they are considered as promising resources, providing energy and preserving proteins for growth. However, rainbow trout is considered as a poor user of carbohydrates displaying postprandial hyperglycaemia and impaired growth performances when fed with diets containing more than 20% of carbohydrates. Nonetheless, recent evidence points that broodstocks could be better user of high carbohydrate diet compared to juveniles. However, no study investigates how sex-reversed females (neomales) eat, grow and reproduce under a high carbohydrate diet. Our objective was thus to assess growth and reproductive performances of neomales fed with a high carbohydrate diet during an entire reproductive cycle. Our results demonstrate that neomales display specific metabolic and physiological changes when fed with a high carbohydrate diet compared to both females and males broodstocks as well as compared to juveniles. Altogether, our data demonstrate the critical relevance to formulate specific diets in accordance with specificities of each type of broodstocks (i.e. females, males and neomales).