News & Views Fish Nutrition Research
Chinese herbs mixture boosts abalone resistance vs. heat stress

Supplementation of a Chinese herbs mixture (CHM) in Japanese abalone (Haliotis discus hannai) diet fortified welfare while exposed to heat-stressed environment. 

“In conclusion, dietary supplementation of CHM improved the growth performance, anti-oxidative capacity, immunity and the resistance to heat stress of abalone. The recommended level of CHM supplemented in diets for abalone was 0.049 per cent,” Rui Wang et. al cited in its recently published study, “The growth performance, anti-oxidative capacity, immunity and resistance to heat stress of abalone Haliotis discus hannai can be improved by a mixture of herbs.” The study was published on Aquaculture Reports.

Study results cited dietary CHM within the range of 0.02 to 0.04 per cent could enhance growth of abalone. Immunity and resistance of the animal to heat stress benefited at 0.04 per cent inclusion. 

The 84-day feeding trial was conducted on juveniles in floating cages in Fujian, China.

The heat stress test was conducted on a seawater tank heated to 28 C and kept at this temperature for 24 hours.

In China, one of the key stressors in abalone has been linked to global warming. Sensitive to its environment, increased water temperature could reduce its immunity levels and survival rates. The use of antibiotics is the conventional approach. Authors considered, however, environmental, health and ethical implications.

The team said Chinese herbs have been used as feed additives in aquaculture due to many advantages: low toxicity, absence of medicine residue, and being non-pollutant and inexpensive. Previous studies have proven the potency of Chinese herbs in terms of growth promotion, appetite stimulation, anti-oxidation, immune-stimulation, anti-stress and liver protection.

The CHM used in the study contained Artemisiae Scopariae Herba (Artemisia capillaris), Uncariae Ramulus Cum Uncis (Uncaria rhynchophylla), Polygoni Cuspidati Rhizoma et Radix (Polygonum cuspidatum).

Increased water temperature aside, intensive farming practices has been identified as another leading cause of mortality in cultured abalone because of disease outbreaks.