Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10820697 | Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology | 2005 | 11 Pages |
Abstract
Carbohydrase activities were examined in Odax pullus (Labridae), Kyphosus sydneyanus (Kyphosidae) and Aplodactylus arctidens (Aplodactylidae) collected from subtidal reefs in northeastern New Zealand. Enzyme extracts were prepared using two methods from gut wall, gut fluid and microbial pellet samples taken serially along the gut, and assayed against the substrates starch, laminarin, carrageenan, alginate and agarose. In all three fish species, starch degradation activity was substantially higher than for any other substrate tested. Activities of 500, 1294 and 3326 units g tissueâ1 were measured in anterior gut wall extracts of O. pullus, K. sydneyanus and A. arctidens, respectively. Starch degrading activity in gut fluid declined from 37, 313 and 284 units mlâ1 in anterior gut sections of O. pullus, K. sydneyanus and A. arctidens, respectively, to less than 50 units mlâ1 in terminal gut section of each species. Activity against structural polysaccharides was much lower than against starch and was detected mainly in posterior gut sections. The two methods of sample preparation differed little in enzyme activities; however, method of sample preparation did affect isoform patterns as displayed by zymogram analysis. Results suggest that these fish species fall on a continuum from maximizing throughput and digesting easily hydrolysed substrates in the foregut in A. arctidens to relying more heavily on microbial fermentation in the hindgut in K. sydneyanus.
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Authors
G.L. Skea, D.O. Mountfort, K.D. Clements,