Gj. Zhao et al., Effects of selected water quality variables on the persistence of tannic acid and related compounds under simulated aquaculture conditions, N AM J AQUA, 61(4), 1999, pp. 304-309
Tannins have potential commercial applications in aquaculture for the preve
ntion of piscine diseases and off-flavor in fish. Selected water quality va
riables, such as temperature, pH, dissolved oxygen, light intensity, total
hardness and total alkalinity, and available nutrients found in fish ponds
were examined for their influence on the fate of gallic acid, methyl gallat
e, propyl gallate, and tannic acid. It was determined that total hardness a
nd alkalinity were the most effective factors in the dissipation of tannin
compounds. High levels of selected water quality variables were significant
ly different from low levels in their ability to transform tannin compounds
. It was also found that natural suspended solids were effective in precipi
tating 60% of the methyl gallate and 81.3% of the propyl gallate per week f
rom solution. Abiotic processes, such as physical transportation and chemic
al transformation, affected the fate of tannin compounds in a simulated fis
h pond. This study may guide the use of tannins as a feed additive or disea
se treatment in the management of fish-farming problems.