# Effects of Cannabis sativa L. Leaves on Opisthorchis viverrini Metacercariae in Infected Barbonymus gonionotus

## TL;DR

This study shows that adding cannabis leaves to fish diets can reduce liver fluke infections and boost the fish's immune response.

## Contribution

The study demonstrates the preventive potential of Cannabis sativa leaves against liver fluke infection in fish.

## Key findings

- Higher doses of cannabis leaves reduced infection rates and intensity of O. viverrini metacercariae.
- Fish fed 2.0% cannabis leaves showed no degeneration of metacercariae after 14 and 21 days.
- Cannabis leaf supplementation increased SOD, lysozyme activity, and IgM levels in fish.

## Abstract

This study is aimed at evaluating the effects of dietary Cannabis sativa L. leaf supplementation on superoxide dismutase (SOD) levels and the prevention of liver fluke (Opisthorchis viverrini) metacercaria infection in Barbonymus gonionotus. The experiment included five treatment groups, with varying concentrations of C. sativa leaves (0.0%, 0.5%, 1.0%, 1.5%, and 2.0%) in the experimental feed. Six hundred parasite-free B. gonionotus (50 days old) were infected with 50 cercariae each. After 24 h, they were fed the experimental feed for 0 (control group), 7, 14, or 21 days. The infection rate, intensity of O. viverrini metacercaria, survival rates, immunoglobulin M (IgM) levels, lysozyme activity, and SOD levels in B. gonionotus were investigated. The results showed that cannabis leaves effectively prevented O. viverrini infection. Fish fed with higher doses of cannabis leaf diets had a decreased infection rate and intensity of O. viverrini metacercariae and higher survival rates. Conversely, there was an increase in SOD, lysozyme activity, and IgM levels. Moreover, after the fish were fed 2.0% cannabis leaves for 14 and 21 days, no O. viverrini metacercariae were degenerated. The highest SOD levels were exhibited by fish fed 2.0% cannabis leaves for 14 days (1497.96 U/g FW), and the metacercariae were inactive and degenerated. In summary, dietary supplementation of cannabis leaves can be used as a preventive measure against liver fluke infection in B. gonionotus.