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: The enzymatic basis for cod digestive lipolysis has been investigated. Lipase activity was found in aqueous extracts from pyloric caeca as well as in pancreatic tissue surrounding the caeca and the bile duct. A bile salt-dependent lipase (BSDL) was purified from either defatted powder of cod pyloric caeca or aqueous pancreatic extracts by combined affinity chromatography on cholate-Sepharose and gel filtration on Sephacryl S-200 HR. By SDS-PAGE analysis the molecular weight of purified cod BSDL was estimated to 60 kDa. The enzyme was totally dependent on bile salts for hydrolysis of insoluble fatty acid esters. Antiserum raised against purified cod BSDL reacted specifically with selected mammalian pancreatic BSDLs by Western blot analysis. Results presented in this paper strongly suggest that the bile salt-dependent lipase is the only pancreatic enzyme involved in lipid digestion in cod. The enzyme has been characterized and compared to human pancreatic BSDL with respect to substrate specificity, temperature- and pH-dependence and inhibitors. Both soluble and insoluble fatty acid esters were hydrolysed and the enzyme was 1,3-specific in hydrolysis of triolein. The enzyme was inhibited by di-isopropyl fluorophosphate and phenyl boronic acid, but not significantly by phenyl methyl sulfonyl fluoride. The cod BSDL is probably homologous to mammalian pancreatic BSDLs.Biochimica et Biophysica Acta 04/1992; 1124(2):123-34. · 4.66 Impact Factor
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ABSTRACT: To estimate the quantitative adequacy of amino acids in practical dietary proteins, free amino acid (FAA) levels in various tissues of rainbow trout Oncorhynchus mykiss fed different protein sources were compared. Four diets, the proteins of which were derived mainly from fish meal (FM diet), soybean meal (SBM diet), malt protein flour (MPF diet), and the combination of SBM and MPF (COMB diet), were fed to duplicate groups (30 fish/group, 10 g/fish) for 6 to 9 weeks at 15°C, until each treatment group reached the weight of the FM diet group attained in 6 weeks. The fish for FAA analysis were sampled 12 h after the last feeding. The body weight of the FM group was attained in 7 weeks by the COMB diet group, and in 9 weeks by the SBM and the MPF diet groups. Concentrations of free threonine, methionine, and lysine in most of the tissues of the COMB diet group, as well as the SBM and the MPF diet groups, were quite lower than those of the FM diet group. Levels of these amino acids between the four diets and most of the tissues examined were highly correlated. Although the threonine content in the COMB diet was slightly lower than the FM diet, these findings suggest that not only methionine and lysine but also threonine is still insufficient in the COMB diet.Fisheries Science 12/2001; 66(2):310 - 320. · 0.90 Impact Factor
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ABSTRACT: Extracts from defatted cod poloric ceaca were used as enzyme source in order to purify and study digestive triglyceride lipase in the cod. By combining ammonium sulphate fractionation, DEAE-cellulose chromatography and gel filtration, a cod triacyl glycerol lipase was purified 200-fold from cod pyloric caeca. The cod lipase showed an absolute requirement for bile salts on olive oil hydrolysis. When tributyrine was used as substrate, the bile salt dependence was less pronounced. The partly purified enzyme was not inhibited by bile salts at concentrations up to 10 mM. The positional specificity of the cod lipase was 1,3-specific for hydrolysis, leaving as end products free fatty acids and 2-monoglycerides. We have not been able to demonstrate a colipase in the extracts from cod pyloric caeca.Aquaculture 01/1989; 79:177-184. · 2.01 Impact Factor