Distribution of thiaminase in different tissues of some fish species from osu reservoir, osun state, south western nigeria

Thesis Abstract

Thiaminase degrade thiamine into separate thiazole and pyrimidine moieties, an enzyme that cleaves vitamin B1 and are sporadically distributed among prokaryotes and eukaryotes. The excess thiaminase in fish tissues causes thiamine deficiency syndrome like neurological and cardiac disorder, it also causes reproductive disorder in fishes and finally leads to death. Thiaminase in human causes thiamine deficiency which leads to beriberi and Wernicke Korsakov syndrome or Wernicke paralysis, it also prevent the conversion of carbohydrate to glucose. Fishes rich in thiaminase are not good for human consumption because it leads to chronic thiamine deficiency.

This present study was carried out to determine the distribution, level and the effect of thiaminase in different tissues of some fish species. A total number of 21 tissues were extracted from 7 different fish species (Gills, gut and flesh i.e. 3 from each). In the tissue, Tilapia Zilli gut had the highest thiaminase activity (27.05±2.08) while Parachanna Africana gill had the lowest activity (0.09±0.12). Tilapia Zilli gut also have the highest specific activity (0.0058±0.0004) Parachanna Africana gill has the lowest specific activity (0.0000±0.0000). Clarias Gariepinus flesh has the highest protein concentration (14387.44±179.13) Hepsetus Odoe gut has the lowest protein concentration (791.28±13.33). Saroterodon Galilaeus species has the highest level of thiaminase activity (10.136ª) and Parachanna Obscura species has the lowest level of thiaminase activity (0.463ᵇ). Tilapia Zilli species has the highest specific activity of (0.0023ª) while Parachanna Africanna species has the lowest specific activity of (0.0002ᶜ).

Gut has the highest thiaminase activity of (11.315ª) while flesh has the lowest thiaminase activity of (1.916ᵇ). Gut also has the highest specific activity of (0.00304ª) and flesh also has the lowest specific activity of (0.00022ᵇ). Therefore, the significance of the study is that excess thiaminase degrades thiamin and causes thiamin deficiency in fishes which leads to various ailments in fish and finally leads to death.