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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Parasiticidal effects of Morus alba root bark extracts against Ichthyophthirius multifiliis infecting grass carp

Authors
item Fu, Yao-Wu -
item Zhang, Qi-Zhong -
item Xu, Dehai
item Xia, Huan -
item Cai, Xin-Xing -
item Wang, Bin -
item Liang, J.H. -

Submitted to: Diseases of Aquatic Organisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 13, 2013
Publication Date: February 11, 2014
Citation: Fu, Y., Zhang, Q., Xu, D., Xia, H., Cai, X., Wang, B., Liang, J. 2014. Parasiticidal effects of Morus alba root bark extracts against Ichthyophthirius multifiliis infecting grass carp. Diseases of Aquatic Organisms. 108:129-136.

Interpretive Summary: The protozoa Ichthyophthirius multifiliis (Ich) is an important fish parasite that can result in significant losses in aquaculture. Currently there is no chemotherapeutant available to treat Ich effectively and economically. In order to find efficacious parasiticides to control Ich, the root bark of Morus alba was evaluated for its anti-parasite effect. The M. alba root bark was powdered with a machine, extracted with chemicals and concentrated under reduced pressure in an evaporator. The extracted M. alba root bark was used in anti-Ich trials. The acetone and ethyl acetate extracts significantly reduced the survival of Ich tomonts and theronts. The results demonstrate that the M. alba extract may be a potential new, safe and efficacious parasiticide to control Ich. The study results are important to the aquaculture industry and will help researchers to develop effective parasiticides against the parasite Ich.

Technical Abstract: Ichthyophthirius multifiliis (Ich) is an important fish parasite that can result in significant losses in aquaculture. In order to find efficacious drugs to control Ich, the root bark of Morus alba, a traditional Chinese medicine, was evaluated for its antiprotozoal activity. The M. alba root bark was powdered with a machine and extracted with one of five chemicals, i.e., petroleum ether, chloroform, ethyl acetate, acetone or methanol. The extracts were concentrated under reduced pressure in a vacuum rotary evaporator, dissolved in 0.1% (v/v) DMSO, and used for anti-Ich trial. The acetone and ethyl acetate extracts significantly reduced the survival of Ich tomonts and theronts. In vitro, acetone extract at concentrations of 25 mg/L killed all tomonts, at 50 mg/L stopped tomont reproduction and at 8 mg/L caused theront mortality. Ethyl acetate extract demonstrated 100% antiprotozal efficacy to tomonts, encysted tomonts and theronts at concentrations of 50, 100 and 8 mg/L, respectively. Even though low concentrations (2 and 4 mg/L) of acetone and ethyl acetate extracts could not kill all theronts after 4 h, a significant decrease of the theront infectivity was observed by 0.5 hour treatment. The 96-h LC50 values of acetone and ethyl acetate extracts to grass carp were 79.46 and 361.05 mg/L, which were much higher than effective doses for killing Ich theronts (8 mg/L of acetone extract and ethyl acetate extract) and tomonts (12.5 mg/L of acetone extract, 25 mg/L of ethyl acetate extract). The results indicate that the M. alba extract may be a potential new, safe and efficacious drug to control Ich.

Last Modified: 10/19/2014
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