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The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata).
Biochim Biophys Acta 2015; 1851(3):248-60BB

Abstract

The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores.

Authors+Show Affiliations

Assay Development Division, Malaysian Institute of Pharmaceuticals and Nutraceuticals, Ministry of Science, Technology and Innovations, Block 5-A, Halaman Bukit Gambir, Penang 11700, Malaysia.School of Biological Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia.School of Biological Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia; Center for Marine and Coastal Studies, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia. Electronic address: alex@usm.my.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25542509

Citation

Kuah, Meng-Kiat, et al. "The Capacity for Long-chain Polyunsaturated Fatty Acid Synthesis in a Carnivorous Vertebrate: Functional Characterisation and Nutritional Regulation of a Fads2 Fatty Acyl Desaturase With Δ4 Activity and an Elovl5 Elongase in Striped Snakehead (Channa Striata)." Biochimica Et Biophysica Acta, vol. 1851, no. 3, 2015, pp. 248-60.
Kuah MK, Jaya-Ram A, Shu-Chien AC. The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata). Biochim Biophys Acta. 2015;1851(3):248-60.
Kuah, M. K., Jaya-Ram, A., & Shu-Chien, A. C. (2015). The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata). Biochimica Et Biophysica Acta, 1851(3), pp. 248-60. doi:10.1016/j.bbalip.2014.12.012.
Kuah MK, Jaya-Ram A, Shu-Chien AC. The Capacity for Long-chain Polyunsaturated Fatty Acid Synthesis in a Carnivorous Vertebrate: Functional Characterisation and Nutritional Regulation of a Fads2 Fatty Acyl Desaturase With Δ4 Activity and an Elovl5 Elongase in Striped Snakehead (Channa Striata). Biochim Biophys Acta. 2015;1851(3):248-60. PubMed PMID: 25542509.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The capacity for long-chain polyunsaturated fatty acid synthesis in a carnivorous vertebrate: Functional characterisation and nutritional regulation of a Fads2 fatty acyl desaturase with Δ4 activity and an Elovl5 elongase in striped snakehead (Channa striata). AU - Kuah,Meng-Kiat, AU - Jaya-Ram,Annette, AU - Shu-Chien,Alexander Chong, Y1 - 2014/12/24/ PY - 2014/05/30/received PY - 2014/12/14/revised PY - 2014/12/16/accepted PY - 2014/12/28/entrez PY - 2014/12/30/pubmed PY - 2015/8/26/medline KW - Channa striata KW - Elongase KW - Long-chain polyunsaturated fatty acids biosynthesis KW - Nutritional regulation KW - Δ4 desaturase SP - 248 EP - 60 JF - Biochimica et biophysica acta JO - Biochim. Biophys. Acta VL - 1851 IS - 3 N2 - The endogenous production of long-chain polyunsaturated fatty acids (LC-PUFA) in carnivorous teleost species inhabiting freshwater environments is poorly understood. Although a predatory lifestyle could potentially supply sufficient LC-PUFA to satisfy the requirements of these species, the nutrient-poor characteristics of the freshwater food web could impede this advantage. In this study, we report the cloning and functional characterisation of an elongase enzyme in the LC-PUFA biosynthesis pathway from striped snakehead (Channa striata), which is a strict freshwater piscivore that shows high deposition of LC-PUFA in its flesh. We also functionally characterised a previously isolated fatty acyl desaturase cDNA from this species. Results showed that the striped snakehead desaturase is capable of Δ4 and Δ5 desaturation activities, while the elongase showed the characteristics of Elovl5 elongases. Collectively, these findings reveal that striped snakehead exhibits the genetic resources to synthesise docosahexaenoic acid (DHA; 22:6n-3) from eicosapentaenoic acid (EPA; 20:5n-3). Both genes are expressed at considerable levels in the brain and the liver. In liver, both genes were up-regulated by dietary C18 PUFA, although this increase did not correspond to a significant rise in the deposition of muscle LC-PUFA. Brain tissue of fish fed with plant oil diets showed higher expression of fads2 gene compared to fish fed with fish oil-based diet, which could ensure DHA levels remain constant under limited dietary DHA intake. This suggests the importance of DHA production from EPA via the ∆4 desaturation step in order to maintain an optimal reserve of DHA in the neuronal tissues of carnivores. SN - 0006-3002 UR - https://www.unboundmedicine.com/medline/citation/25542509/The_capacity_for_long_chain_polyunsaturated_fatty_acid_synthesis_in_a_carnivorous_vertebrate:_Functional_characterisation_and_nutritional_regulation_of_a_Fads2_fatty_acyl_desaturase_with_Δ4_activity_and_an_Elovl5_elongase_in_striped_snakehead__Channa_striata__ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1388-1981(14)00264-9 DB - PRIME DP - Unbound Medicine ER -