Effect of dietary taurine and lipid contents on conjugated bile acid composition and growth performance of juvenile Japanese flounder Paralichthys olivaceus
ABSTRACT The effects of dietary taurine levels and lipid contents on the conjugated bile acid composition and growth performance of juvenile Japanese flounder Paralichthys olivaceus were investigated. Six types of diet (three different levels of taurine at two different levels of lipid) were fed to juveniles (average body weight, 0.04 g). Fishmeal that was washed with 70% ethanol to remove taurine was used as the sole protein source. Feeding experiments were carried out at 20°C for 6 weeks. At the end of the experiments, fish were weighed and analyzed for free amino acids in the body and the composition of the conjugated bile acids. The body weight and percent weight gain of the juveniles were improved by the dietary taurine supplementation. The taurine contents of the whole body and tissues increased with the increase of the dietary taurine contents. The conjugated bile acids in the gall bladder consisted of taurocholic acid and taurochenodeoxycholic acid, which increased with the increase of the dietary taurine level. Taurocholic acid accounted for more than 95% of the total conjugated bile acids. This indicates that taurine is the sole amino acid to conjugate bile acid in Japanese flounder.
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ABSTRACT: Taurine, which has multiple important physiological roles in teleost fish and mammals, is an amino acid not found in alternative protein sources not derived from animals. Although taurine is found in fish-meal-based feeds, its high water solubility leads to lower taurine levels in reduction-process-based feeds, which marine carnivores such as Cobia Rachycentron canadum are adapted to in their natural diets. Graded taurine supplementation (0, 0.5, 1.5, and 5.0%) added to a traditional fish-meal-based formulation was examined in two growth trials with Cobia: one initiated with 10-g individuals and the second initiated with 120-g individuals. During the first trial, in which growth as weight gain ranged from 123 to 139 g per fish, there was an increase in dietary taurine and a decrease in the feed conversion ratio from 1.04 to 0.99. During the second trial, in which growth ranged from 227 to 313 g gained per fish, there was no significant difference in performance characteristics between dietary treatments. Messenger RNA transcript expression levels for two of the genes involved in taurine synthesis, cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), as well as the membrane-bound taurine transporter, TauT, were also measured at the conclusion of the second trial. Increasing dietary taurine in a diet containing 34.5% fish meal did not result in significantly different growth or production characteristics in Cobia, but did result in significantly increased taurine levels in fillet, liver, and plasma.Received July 23, 2013; accepted January 20, 2014North American Journal of Aquaculture 07/2014; 76(3). DOI:10.1080/15222055.2014.899531 · 0.71 Impact Factor
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ABSTRACT: Two feeding trials were conducted to initiate the development of a practical soy-based diet for California yellowtail (YT), Seriola lalandi. The first trial evaluated fish meal (FM), FM + solvent-extracted soybean meal (SBM) or FM + soy protein concentrate (SPC)-based diets and a commercial reference diet (Skretting Marine Grower). Final weights (31.8–67.6 g), per cent gain (492.8–1059.9%) and feed conversion ratio (1.11–1.59) all followed a similar response in that fish offered the commercial diet performed significantly better than fish maintained on the other diets. The second trial was designed to evaluate the replacement of FM with increasing levels of soy protein. The basal diet contained 400 g kg−1 FM and 240 g kg−1 SBM. The FM was then reduced to 300 g kg−1, 200 g kg−1 and 150 g kg−1 of the diet using SPC as the replacement protein. Final weight (41.2–64.1 g) and per cent gain (110.5–226.5%) followed similar trends with decreases in performance as the FM level was reduced. No gross signs of enteritis were noted, indicating that reduced performance was likely due to nutrient deficiencies or palatability problems rather than an allergic response. Results demonstrate that there is potential to develop reduced FM diets for this species using soy protein.Aquaculture Nutrition 08/2011; 17(4). DOI:10.1111/j.1365-2095.2011.00856.x · 1.67 Impact Factor
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ABSTRACT: In seedling production of seawater fish, providing appropriate nutrition is a necessity for successful production of quality larvae and juveniles. Mass-produced live prey organisms, such as the rotifer Brachionus plicatilis species complex and brine shrimp Artemia spp., alone do not provide sufficient nutrition to the larvae and juveniles of seawater animals. This inadequacy has led to various problems related to fish quality and health, including increased incidence of morphological and behavioral abnormalities and mass mortalities. It is, therefore, important to identify the factors associated with these problems to improve seedling production techniques. This review collates the efforts made during the past two decades in larval nutrition–focusing on advances made in the use of certain nutrients, such as docosahexaenoic acid, vitamin A derivatives, and taurine that are important for the mass production of seawater fish larvae and juveniles–with an aim to improve the quality and health of fish.Fisheries Science 05/2014; 80(3):389-403. DOI:10.1007/s12562-014-0744-8 · 0.86 Impact Factor