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Annette Jaya-Ram Alexander Chong Shu-Chien Meng-Kiat Kuah 《Fish physiology and biochemistry》2016,42(4):1107-1122
Despite the potential of vegetable oils as aquafeed ingredients, a major drawback associated with their utilization is the inferior level of beneficial n-3 long-chain polyunsaturated fatty acids (LC-PUFA). Echium oil (EO), which is rich in stearidonic acid (SDA, 18:4n-3), could potentially improve the deposition of n-3 LC-PUFA as the biosynthesis of LC-PUFA is enhanced through bypassing the rate-limiting ?6 desaturation step. We report for the first time an attempt to investigate whether the presence of a desaturase (Fads2) capable of ?4 desaturation activities and an elongase (Elovl5) will leverage the provision of dietary SDA to produce a higher rate of LC-PUFA bioconversion. Experimental diets were designed containing fish oil (FO), EO or linseed oil (LO) (100FO, 100EO, 100LO), and diets which comprised equal mixtures of the designated oils (50EOFO and 50EOLO) were evaluated in a 12-week feeding trial involving striped snakeheads (Channa striata). There was no significant difference in growth and feed conversion efficiency. The hepatic fatty acid composition and higher expression of fads2 and elovl5 genes in fish fed EO-based diets indicate the utilization of dietary SDA for LC-PUFA biosynthesis. Collectively, this resulted in a higher deposition of muscle eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) compared to LO-based diets. Dietary EO improved the ratio of n-3 LC-PUFA to n-6 LC-PUFA in fish muscle, which is desirable for human populations with excessive consumption of n-6 PUFA. This study validates the contribution of SDA in improving the content of n-3 LC-PUFA and the ratio of EPA to arachidonic acid (ARA, 20:4n-6) in a freshwater carnivorous species. 相似文献
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K.W. Peng S.F. Chew C.B. Lim S.S.L. Kuah W.K. Kok Y.K. Ip 《Fish physiology and biochemistry》1998,19(1):59-69
A lipase was purified from the extract of the delipidated powder of red sea bream hepatopancreas to nar homogeneity by fractional precipitation with ammonium sulfate and sequential chromatography on first anion-exchange-, hydrophobic- and second anion-exchange columns followed by gel filtration and anion-exchange HPLC. The final enzyme preparation showed a single band with an apparent molecular mass of approx. 64 kDa by sodium dodecyl sulfate-polyacrylamid e gel electrophoresis. The purified enzyme had a pH optimum in the range of pH 7.0–9.0. Using -nitrophenyl myristate or triolein as a substrate, the enzyme required the presence of sodium taurocholate or sodium cholate for its activity. No activity was observed in the presence of sodium deoxycholate. The enzyme preferentially hydrolyzed ethyl esters of polyunsaturated fatty acid, such as arachidonic acid and eicosapentaenoic acid which were resistant to porcine pancreatic lipase. These results strongly suggest that the enzyme purified from the hepatopancreas of red sea bream is homologous to mammalian bile salt-activated lipase. 相似文献
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Aliza D Ismail IS Kuah MK Shu-Chien AC Tengku Muhammad TS 《Fish physiology and biochemistry》2008,34(2):129-138
Copper is one of the major heavy metal pollutants found in the aquatic environment. Therefore, it is important for determining
the genes that play a key role in copper metabolism in aquatic organisms. This study, thus, aimed to identify a new copper-inducible
gene in swordtail fish, Xiphophorus helleri. Using ACP-based RT-PCR coupled with RLM-RACE, we cloned Wap65, a mammalian homologue of hemopexin gene. The gene exhibits
high identity at amino acid levels with the Wap65 gene of other fish species (42–68%) and mammalian hemopexin gene (35–37%).
In addition, ten cysteine and two histidine residues are conserved in the swordtail fish Wap65 gene. These cysteine residues
are vital for structural integrity, and histidine residues provide high binding affinity towards heme. As revealed by RT-PCR,
the gene was upregulated in swordtail fish that were exposed to copper in a dose- and time-dependent manner. Therefore, the
identification of Wap65, a mammalian homologue of hemopexin, as a new copper-inducible gene will provide greater insight into
the role of this gene in copper metabolism. 相似文献
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Sam Ka-Kei Lau Nyok-Sean Kuah Meng-Kiat Lading Engkamat anak Shu-Chien Alexander Chong 《Fish physiology and biochemistry》2022,48(4):817-838
Fish Physiology and Biochemistry - The capacity for long-chain polyunsaturated fatty acid (LC-PUFA) biosynthesis activity in a species depends on the enzymatic activities of fatty acyl desaturase... 相似文献
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