Effect of taurine enrichment in rotifer ( Brachionus sp.) on growth of larvae of Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel) and yellowfin tuna T. albacares (Temminck & Schlegel)

Abstract

To investigate the dietary effect of taurine on the larval stage of tuna species, Pacific bluefin tuna (PBF) and yellowfin tuna (YFT), larvae were reared until 16 days after hatching (dAH) and 14 dAH, respectively, and replicate samples were fed either non-taurine-enriched rotifers (T-0) or rotifers enriched with 800 mg taurine L À1 (T-800). Most PBF and YFT larvae were at the preflexion stage until 7 and 8 dAH, and there were no differences in the growth performance and total protein content of larvae between the T-0 and T-800 groups (t-test; P > 0.05). Thereafter, however, for larvae of both species, these parameters in the T-800 group significantly increased with enhanced notochord development compared to those in T-0 group (t-test; P < 0.05). Except for the RNA content in PBF larvae, there were no significant differences in changes of DNA and RNA content with larval growth between the T-0 and T-800 groups, but both PBF and YFT larvae showed increased protein DNA À1 and protein RNA À1 ratios in the T-800 group compared to the T-0 group after notochord flexion. This indicates that taurine is an important nutrient for the rapid growth of early stage PBF and YFT larvae, and we conclude that the growth improvement of PBF and YFT larvae by dietary taurine supplementation is due to the increase in protein synthesis efficiency after notochord flexion.

Taurine metabolism and effects of inclusion levels in rotifer (Brachionus rotundiformis, Tschugunoff, 1921) on Atlantic bluefin tuna (Thunnus thynnus, L.) larvae

“…In order to confirm an active role for taurine metabolism including biosynthesis in ABT, a trial was carried out by feeding larvae from mouth opening to 14 dah with different levels of taurine supplied via rotifers enriched with increasing levels of taurine. Taurine concentration in larvae was strongly correlated to the level of taurine enrichment in rotifer in agreement with previous trials (Matsunari et al, 2007;Katagiri et al, 2017;Koven et al, 2018). This confirms that ABT larvae are able to assimilate dietary taurine into their tissues and may reflect a taurine requirement.…”

“…Indeed, a recent study in Pacific bluefin (Thunnus orientalis) and yellowfin tuna (T. albacares) larvae demonstrated that feeding rotifers enriched with 800 mg taurine L -1 promoted larval growth and total protein content (Katagiri et al, 2017), suggesting that taurine is an important nutrient for the early stages of rapidly growing teleost species.…”

Molecular aspects of lipid metabolism, digestibility and antioxidant status of Atlantic bluefin tuna (T. thynnus L.) larvae during first feeding

“…However, not only lipids and essential fatty acids, but other nutrients such as antioxidants (vitamin E, vitamin C and Se) and taurine, have been proposed as essential components for fast growing marine fish species, particularly in tuna which cannot synthesize these compounds (Yokohama et al, 2001;Waagbø, 2010;NRC, 2011;Izquierdo and Betancor, 2015;Katagiri et al, 2016). Indeed, growth in fish is primarily due to protein deposition with most marine fish larvae having a high requirement for essential amino acids (Rønnestad et al, 2003).…”

“…Live foods that are commonly used for larval marine fish rearing (including tunas), such as rotifers (Brachionus sp. ), have naturally low levels of essential fatty acids (Maehre et al, 2013;Takeuchi, 2014;Kostopoulou et al, 2015), vitamins E and C, Se, iodine (Hamre et al, 2008;2013), taurine (Takeuchi, 2014;Katagiri et al, 2016) and essential amino acids (Rajkumar and Kumaraguru vasagam, 2006), especially when compared with copepods, the natural prey of tuna larvae (van der Meeren et al, 2008;Maehre et al, 2013). In this context, successful larval production of marine fish depends upon the supply of live feed fortified with the essential nutrients that are insufficient in the live feeds.…”

Effect of stocking density and feeding regime on larval growth, survival, and larval development of Japanese flounder, Paralichthys olivaceus, using live feeds

“…Enrichment can increase the fatty acid content and other essential nutrients of live feeds, which are crucial to the development of fish larvae (Li & Olsen, ; Morais & Conceição, ). The inclusion of the organic acid taurine in live feeds has been shown to be effective in enhancing the growth of fish larvae of a variety of species (Katagiri et al, ; Kim et al, ; Matsunari et al, ; Partridge & Woolley, ). Microbound diets, a potential replacement of live feed, have been developed by many researchers and used to partially replace the live feed without affecting the survival rate and growth of Japanese flounder larvae (Kanazawa, Koshio, & Teshima, ; Takeuchi et al, ; Teshima, Koshio, Ishikawa, Alam, & Hernandez, ).…”