Effects Of Different Mushroom (Agaricus Blazei) Extracts On Infective Abilities Of White Spot Syndrome Virus

Recently, the shrimp industry has always been affected by viral diseases. The white spot syndrome viral disease is the major disease in shrimp farm. So it is important and valuable to study the WSSV. We studied the effects of different mushroom (Agaricus blazei) extracts on infective abilities White Spot Syndrome Virus (WSSV) to the primary cultured lymphocytes from the shrimp, Marsupenaeus japonicus, in order to investigate the antiviral activity of Agaricus blazei extracts against WSSV and find the high antiviral active component of Agaricus blazei to prevent WSSV.In this study, in order to obtain WSSV for the followed experiments, we infected the shrimp by injecting the WSSV solution; WSSV were proliferated in the shrimp in vivo. . The WSSV was obtained from the heart, lymph and grill of the infected shrimp with WSSV by detection of PCR. The results indicated: after the shrimps were injected with WSSV, the mortality rate of the shrimp is 100% in 7days. The infected shrimp show lethargy, a pink to reddish-brown coloration and followed by death. The infected rate of the shrimp is 85% by PCR detection.In order to investigate the antiviral activity of the Agaricu ablazei extracts against WSSV in vitro, we cultured the lymphocytes of the shrimp and prepared (0.05%, 0.1%, 0.15%) the water extracts from Agaricus blazei at three different temperatures (60, 25 and 4℃). The lymphocytes were infected by WSSV reacted with the water extract of the mushroom at different concentration for 1 hour. The result indicated: WSSV can infect the shrimp lymphocytes in vitro. The water extracts from the mushroom inhibited the occurrence of cytopathic effect (CPE) induced by WSSV on the shrimp lymphocytes in vitro. The result of PCR detection indicated that the water extract from the mushroom can not completely inhibit WSSV to infect the shrimp lymphocytes. The inhibitory effect of 0.1% the room temperature water (25 ℃)extracts and 0.15% the hot water (60 °C) extracts from the mushroom is more significant than the others.We farther preciptated the hot water extracts of the mushroom with the different concentration of ethanol and obtained five kinds of the Agaricus fractions. The result of cytotoxicity test showed that after the lymphocytes were cultured with the K199 medium included 2mg/mL Agaricus fraction for 24 hours, all kinds of Agaricus fraction had the cytotoxicity to the lymphocytes of the shrimp in vitro. After cultured for 72 hours, in the 17% ethanol precipitation test group a few of cell shrank and detached from the surface of the culture plank; in the 50% ethanol precipitation test group some cell shrank. In the challenge test, the occurrence of CPE induced by WSSV became weak as the WSSV were diluted. When the WSSV were diluted 30 times, the 17%, 29%, 38% ethanol precipitation of the hot water extracts of the mushroom can completely inhibit WSSV to infect the shrimp lymphocytes in vitro by PCR detection.