Seaweed-based diets lead to normal growth, improved fillet color but a down-regulated expression of somatotropic axis genes in rainbow trout (Oncorhynchus mykiss)

Administration of Red Macroalgae (Galaxaura oblongata) in the Diet of the Rainbow Trout (Oncorhynchus mykiss) Improved Immunity and Hepatic Gene Expression

“…Nevertheless, in this study, the fish that received dietary G. oblongata exhibited no significant improvement in growth parameters (WG, SGR, and FCR). These findings are consistent with those obtained by Vazirzadeh et al [10], who claimed that the long-term (83-day) administration of 5% and 10% red algae (Gracilariopsis persica and Hypnea flagelliformis) and brown algae (Sargassum boveanum) had no remarkable effect on the growth performance and FCR of rainbow trout. Similarly, the growth performance in zebrafish supplemented with Gracilaria gracilis (0.25, 0.5, and 1%) [47] and Persian sturgeon (Acipenser persicus) supplemented with G. persica (2.5, 5, and 10 g kg −1 diet) [48] was not significantly different from fish fed non-supplemented feeds.…”

“…Among marine organisms, photosynthetic microalgae and some macroalgae (seaweeds) can be considered the foundation of the aquatic food web [9,10]. Macroalgae can generate a broad spectrum of primary and secondary metabolites [11,12] and thus is known as one of the most valuable sources of natural antioxidants and antimicrobial agents [13].…”

“…The nutritional and antinutritional contents of macroalgae commonly differ between genera, according to the region where the algae are collected and the season. Therefore, not all macroalgae have the same beneficial effects on all aquatic species [10]. In this sense, most of the research evaluating macroalgae's effects in aquafeeds has focused on some genera such as Ulva, Sargassum, Gracilaria, and Porphyra species [12].…”