農業部-水產試驗所全球資訊網農業部-水產試驗所全球資訊網

五倍子富含多酚化合物，具強抗菌力，唯嗜口性差，魚不喜食。瓶鼻海豚鏈球菌是尖吻鱸的主要病原菌，因此，本研究將五倍子藥材精萃，探討其在生體外對鏈球菌之抗菌力、對魚成長及拮抗鏈球菌感染症之抗病效力；結果發現五倍子生藥、科學中藥、生藥精萃物及科學中藥精萃物在生體外對鏈球菌皆具強抗菌力。五倍子精萃物之總酚含量比來源材料提高1.5倍；若以0、0.5及1% 添加於飼料，投餵尖吻鱸14天及21天後以瓶鼻海豚鏈球菌攻擊，結果發現所有五倍子精萃物添加組之抗病力皆顯著優於對照組 (p < 0.01)，且投餵14天及21天之組間或自不同材料來源製備之精萃物間之抗病力皆無顯著差異 (p > 0.05)；此外，五倍子精萃物添加組之增重顯著高於對照組 (p < 0.05)。若將五倍子精萃物以0、0.5、1及1.5% 添加於飼料投餵鱸魚14天，再以瓶鼻海豚鏈球菌進行攻擊，同樣地所有添加組之抗病力皆顯著優於對照組 (p < 0.01)，保護力依序各提高25.0±3.8%、50.0±2.3% 及56.7±2.3%，且1% 及1.5% 添加組間無顯著差異 (p > 0.05)。所以，五倍子精萃物的建議用法為1%投餵14天，除能提高鱸魚對鏈球菌感染症之抗病效力，亦可促進成長。

Galla chinensis is rich in polyphenolic compounds and has strong antibacterial ability but has poor palatability and results in fish refusing to eat. Streptococcus iniae is the main pathogen of bacterial diseases of the Asian seabass (Lates calcarifer). Therefore, this study aimed to prepare extracts from the crude herb and modern herbal medicine of G. chinensis to examine the antibacterial abilities of G. chinensis extracts in vitro and their effects on the growth and disease resistance to S. iniae infection in the Asian seabass. The results revealed that all the preparations of G. chinensis, i.e., the crude drug, the modern herbal medicine, and the extracts from the crude drug and modern herbal medicine, have strong antibacterial activity against S. iniae in vitro. The contents of total polyphenols in both G. chinensis extracts were 1.5 times higher than those in the source medicinal materials of G. chinensis. The Asian seabass were fed diets containing 0, 0.5 and 1% of extracts from the crude drug and modern herbal medicine of G. chinensis, respectively, for 14 and 21 days and then challenged with S. iniae. All the G. chinensis extract-added groups had significantly higher disease resistance (p < 0.01) and percent weight gain (p < 0.05) than the control group. There was no significant difference in disease resistance between the groups fed for 14 and 21 days or between the extracts prepared from different material sources ( p > 0.05). If the Asian seabass were fed with G. chinensis extract at doses of 0, 0.5, 1 and 1.5% in feed for 14 days then challenged with S. iniae, the disease resistance of all the extract-added groups was significantly better than that of the control group (p < 0.01), with the protective abilities increased by 25.0 ± 3.8%, 50.0 ± 2.3%, and 56.7 ± 2.3%, respectively. There was no significant difference between the 1% and 1.5% addition groups (p > 0.05). In conclusion, a diet containing G. chinensis extract at a dose of 1% in feed for 14 days is recommended to provide significant protection against S. iniae infection and promote growth in the Asian seabass.