Hibiscus Protects Trout from Ammonia - Study 0 4

The situation can be improved by changing the conditions in which the fish are kept. However, it is also desirable to have a means capable of reducing the negative impact of ammonia on fish health. Researchers from scientific institutions in Iran and Thailand report in the journal Aquaculture that a powder made from hibiscus, known as Sudanese rose, could serve as such an anti-ammonia agent. A drink called hibiscus tea is made from the flowers of the Sudanese rose; its leaves and other parts contain various beneficial substances with antispasmodic, antipyretic, and diuretic effects.

For the experiment, about fifty young rainbow trout weighing approximately 8 grams each were selected and distributed among several sixteen-liter aquariums, with forty fish in each. Some fish were given regular feed, while others were supplemented with 0.5% hibiscus powder, and a third group received 1% of this additive. After two months, the fish were transferred for one day to aquariums with elevated concentrations of ammonium ions (i.e., with high levels of ammonia).

In all fish, ammonia activated inflammatory enzymes and increased the levels of inflammatory proteins in the liver; accordingly, the content of anti-inflammatory and anti-infectious molecules was lower. Meanwhile, the trout receiving the 0.5% Sudanese rose powder supplement showed faster growth and became larger. All fish that received the hibiscus supplement had better liver and immune system conditions, with lower levels of inflammatory molecules in the blood and higher levels of antibodies, while the mucus covering their bodies provided better protection against bacteria. Overall, the authors of the study recommend adding 0.5–1% hibiscus food supplement to enhance the health of fish for more successful breeding of rainbow trout.