Impact of maternal DHA-enriched plant-based diets on early development of rainbow trout offspring: insights into...

To promote sustainable aquaculture, plant-based ingredients are increasingly replacing fish meal (FM) and fish oil (FO) in aquafeeds, altering broodstock diets and reducing omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFAs), essential for reproductive success and progeny growth. Despite the critical role of ω-3 LC-PUFAs, particularly docosahexaenoic acid (DHA) in brain function, data on how fry cope with FM/FO-free diets during early development remain limited. To address this, we conducted a 2-year experiment comparing three broodstock diets: a commercial diet (C diet), a total plant-based diet (V1 diet), and a plant-based diet supplemented with DHA-rich Schizochytrium sp. microalgae oil (V2 diet). After reproduction, progeny were fed either a C diet or a plant-based diet (V). Six groups (C-C, C-V, V1-C, V1-V, V2-C, V2-V) were analyzed for survival, feed intake, and growth, as well as neuropeptide, neurotransmitter, and intestinal hormone expression. Results showed enhanced robustness in fry-fed V diets, particularly from V1 and V2-fed broodstock, with improved survival and feed intake. Fry from DHA-supplemented broodstock (V2-V) compensated for initial growth delays, achieving growth comparable to fry from commercial-fed mothers (C-V) within 30 days. Neurophysiological and gut-brain adaptations revealed complex compensatory mechanisms enabling fish to thrive on sustainable diets. These findings highlight the potential of DHA supplementation in plant-based diets to support sustainable aquaculture and warrant further validation under diverse nutritional and environmental conditions.

The online version contains supplementary material available at 10.1007/s42995-025-00316-7.