This research investigated the changes in body adipocyte size and density as well as parameters relating to adipogenesis in growing cobia, Rachycentron canadum. The cobia from a same batch were sampled 5 , 7 , 9 , 13 , 17 , 21 , 26 and 31 weeks after hatching, Liver activities of fatty acid synthase, (FAS), mailc enzyme (ME), and glucose-6-phosphate dehydrogenase (G6PDH) as well as serum total triacylglycerol (TG), total cholesterol (TC), phospholipid (PL), non-esterified fatty acid (NEFA) were assayed. Adipocyte abundance and size spectrum in liver, ventral muscle and dorsal muscle were determined. The cobia attained an average weight of 13.6 ¡Ó 0.5 g at week 5, and were cultured in nursery outdoor ponds until an average weight 87.5 ¡Ó 3.8 g when moved to open ocean cages. They grew to an average weight 1690.8 ¡Ó 106.6 g at week 31. The crude lipid content in liver, ventral and dorsal muscle increased significantly with fish age, and were 36.1 ¡Ó 3.2 g, 14.8 ¡Ó 0.2g, 4.6 ¡Ó 0.0 g at week 31. No significant change was found in hepatic FAS activity. Hepatic ME activity increased significantly after the fish were stocked in the cages. Whilr hepatic ME activity reduced with age, TG and PL were both increased significantly with age. While adipocyte diameter in liver showed a decreasing trend as the fish grew its abundance increased significantly at week 13 and maintained between 3070¡ã3356 x 104 cell/g tissue during week 17-31. Similarly, adipocyte abundance in ventral muscle increased significantly at week 13, and maintained between 255¡ã269 x 104 cell/g tissue afterwards. There was no significant change in size of ventral muscle adipocyte as fish grew. These results indicate that the adipocyte hyperplasia occurred during week 7- 13, when body weight was 100- 400 g. Adipocyte hypertrophy was observed when the fish reached week 31, there was a sign of adipocyte hypertrophy in liver when the fish were at the last phase of nursery outdoor ponds before being moved to the offshore cages.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0807106-191004 |
| Date | 07 August 2006 |
| Creators | Chen, Jiun-Jhang |
| Contributors | Li-Lian Liu, none, Houng-Yung Chen |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0807106-191004 |
| Rights | unrestricted, Copyright information available at source archive |
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