a medicinal herb easily available in India can increase the resistance to disease and ensure better growth among some of the commonly consumed fish, according to a recent study by scientists at the Delhi University.
Rina Chakrabarti and Vasudeva Rao studied the effect of Achyranthes aspera on Catla catla (commonly called catla) and Labeo rohita (rohu), both of which are freshwater fish. The roots and seeds of the plant were grinded and mixed with the fish feed. The scientists observed an increase in growth as well as resistance to infectious diseases in the fish, which, they say, was a result of the plant enhancing both their specific and non-specific defence mechanisms. The findings were recently published in two journals -- Fish and Shellfish Immunology (Vol 18, No 4) and Aquaculture (Vol 238, Nos 1-4).
The findings are significant for aquaculture in India, one of the world's major fish producers. "To increase production, fishes will have to be given high nutrient value food and must be protected against diseases. But repeated use of antibiotics works out to be expensive, and will affect both the fishes as well as the aquatic ecosystem," says Chakrabarti, adding the herb can be a cheap alternative. The scientists calculated that for every 100 gramme of fish feed, 0.5 g of A aspera will be optimum for immune stimulation and increasing resistance of fishes against bacterial pathogen Aeromonas hydrophila. "This bacteria is one of the most common and dangerous and affects the fish population at large," adds Chakrabarti.
A aspera is found in Asia, South America and Africa. Although the plant's effect on humans is yet to studied but as Chakrabarti says, "Who won't go for a fish that is disease-free, especially when a plant ingredient has been used rather than a synthetic product to increase its productivity and resistance against diseases?"