Study of Anti-NNV Substance Produced by Bacteria Isolated from the Intestine of Grouper

石斑魚消化道細菌分泌抗神經壞死症病毒物質之研究

張莉(Li Chang) ； 齊肖琪(Shau-Chi Chi)

《Acta Zoologica Taiwanica》 14卷2期 (2004/10) Pp. 113-114

https://doi.org/10.6576/AZT.2004.14.(2).12

摘要

神經壞死症病毒是近年來海水養殖魚的重要病原體，本實驗目的在測試魚體腸內菌作爲生物性防疫的可能性。自石斑魚腸道分離並鑑別菌叢，並依菌液上清液對NNV的中和能力，挑選出兩株具有抗NNV活性的菌株，中和力價指數都大於5。以不同孔徑分子篩及高溫處理菌液，發現這兩株細菌所分泌的抗病毒物質皆能耐受100℃高溫處理，但分子量一個大於5000kD，一個小於3000kD，這些物理特性可作爲日後分離純化該物質的依據。將細菌與飼料混合後餵食魚隻，三天後分離並培養消化道菌叢，結果發現餵食組菌叢與負對照組菌叢明顯不同，且能表現抗NNV活性，代表抗病毒細菌餵食後可順利通過消化作用，並在腸道存活下來。

關鍵字

石斑魚 ； 神經壞死症病毒NNV ； 腸內細菌相 ； 生物性防疫

並列摘要

Nervous necrosis virus (NNV) is a critically important pathogen for reared marine fish in recent years. The aim of this study is to evaluate the possibility using ani-viral bacteria as a biological control for NNV disease. The normal flora of grouper intestine was isolated and identified. Anti-NNV bacteria clones were selected according to the result of neutralization test using the culture supernatant of each bacteria clone, and two clones with Log NI＞5 were used for the following tests. The anti-NNV substances in the culture supernatants of the two selected clones were found to be stable at 100℃, and the size of the anti-NNV substance in one bacteria clone is larger than 5000 KD, and in another clone is smaller than 3000 KD. These physical properties would be applied for the design of the purification of the anti-NNV substance. In the feeding test, the cultured bacteria were mixed with commercial food and fed grouper larvae for three days. The intestinal flora of groupers was examined again, and the composition of intestinal flora of the fed grouper was different from that of negative control fish. Moreover, anti-NNV activity was detected again in one of the intestinal bacteria isolated from the fed groupers.

並列關鍵字

grouper ； nervous necrosis virus NNV ； intestinal flora ； biological control