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Digestion and Assimilation of Periphytic Detrital Aggregate by Tilapia mossambica
Author(s) -
Bowen Stephen H.
Publication year - 1981
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1981)110<239:daaopd>2.0.co;2
Subject(s) - assimilation (phonology) , detritus , mugil , organic matter , digestion (alchemy) , biology , tilapia , algae , ecology , chemistry , fishery , environmental chemistry , fish <actinopterygii> , chromatography , philosophy , linguistics
Tilapia mossambica in Lake Valencia, Venezuela, feeds almost exclusively on periphytic detrital aggregate (PDA), a complex aggregation of detritus, algae, and bacteria. The food passes unaltered through the buccal cavity to the stomach. Gastric acid at a pH uncommonly low for fishes (pH < 1.5) decomposes large amounts of inorganic matter and liberates some protein. Intestinal digestion and assimilation of most organic matter are completed in the first half of the intestine. Assimilation efficiencies determined by a field technique were total organic matter 63%, protein 77%, and carbohydrate 63%. When compared to available literature, these results indicate that the two best known detritivorous fishes, T. mossambica and Mugil cephalus, confront similar obstacles in digestion of detrital aggregate, but have overcome these obstacles by physiologically divergent digestive processes.