- 學位論文
養殖午仔魚主要細菌性病原鑑定及疾病研析
Studies on major bacterial diseases in cultured threadfin (Eleutheronema tetradactylum)
若您是本文的作者，可授權文章由華藝線上圖書館中協助推廣。
摘要
午仔魚為台灣南部近年新興養殖魚種之一，但於飼養過程中常因養殖池水品質不優、放養密度過高等因素常導致疾病（如水質差、放養過多），感染造成魚隻高死亡率及感染病症後使用藥物治療之停藥期而延遲上市時間都重創產業。許多疾病感染時一旦垂直發生於種魚階段，常藉由卵的傳播，導致魚苗死亡率提高。細菌性問題會垂直發生種魚的卵、導致魚苗至上市前死亡率提高，細菌會經由鰓侵入魚類組織中造成感染，如鏈球菌、愛德華氏菌、發光桿菌、奴卡氏菌、溶藻弧菌及副溶血性弧菌引起之敗血症，在午仔魚細菌中為重要性疾病。本研究目的為研析午仔魚主要之細菌性感染疾病種類與發生季節概況，並經由臨床症狀、水質檢測、細菌學分離培養及分子生物學菌種鑑定以了解各種疾病發生比例，作為未來對於養殖午仔魚養殖管理及疾病防治之重要參考。本研究自2019年1月起至2022年7月止，共收集1588件病例。研判結果中飼養管理發生率為73.9%（1174/1588）、細菌性疾病發生率為12.5%（198/1588）、寄生蟲性疾病發生率為6.5%（103/1588）、正常發生率為5.4%（85/1588）、病因不明發生率為1.7%（27/1588）、病毒性疾病發生率為0.1%（1/1588）。在細菌性病原之菌種鑑定結果中以Streptococcus iniae 最高佔50.5%（100/198）、Photobacterium dameslae subsp. piscicida其次23.2%（46/198）、Vibrio spp. 8.1%（16/198）、Photobacterium dameslae subsp. damselae 7.6%（15/198）。隨養殖水溫之改變，各種病原菌之浮現適溫，鏈球菌、發光桿菌及弧菌皆隨溫度變化死亡率顯著上升。各細菌結果如下：S. iniae 29.4 ± 2.63、P. piscicida 27.7 ± 3.37、Vibrio spp. 26.4 ± 4.3、P. dameslae 25.8 ± 2.36。而根據不同養殖時期水質檢測結果及不同病原細菌之藥物敏感性試驗結果顯示，當養殖後期池水中亞硝酸高於正常值，午仔魚體型愈大所使用的抗生素抗藥性較高，相對能選擇上市期藥物治療選擇愈少。綜合養殖水溫度、病原菌分離率及魚隻死亡率分析結果顯示：在季節變化中體型小病魚較容易造成病原侵入而死亡；體型中大病魚主要於水溫轉冷時死亡率提高。而養殖期各階段都有鏈球菌、發光桿菌、愛德華氏菌感染病症的發生，但成魚階段養殖則以奴卡氏菌、弧菌及複合性感染居多。綜合本研究結果發現午仔魚細菌性病原的總被分離率有不斷增多的趨勢，尤其與水環境溫度變化確實有正向關聯，當水溫較高期（夏季）死亡率攀升的同時，鏈球菌以分離率亦較高，而冬季低水溫期間以發光菌為主要被分離之細菌性病原。且兩者目前以抗生素感受性測試結果已出現部分藥物的抗藥性菌株，對於未來本魚種持續集約化養殖型態上，細菌性疾病治療之成效仍相當棘手。
並列摘要
Threadfin fish is one of the emerging fish species in southern Taiwan in years. However, during the breeding process, due to factors such as poor water quality in the breeding pond and high stocking density, diseases (such as poor water quality and excessive stocking) often lead to diseases (such as poor water quality, excessive stocking), and infection leads to high mortality of fish. The industry has been hit hard by the delay in time-to-market due to the high rate of infection and the withdrawal period of drug treatment. Once the infection of many diseases occurs vertically in the breeding fish stage, it is often spread through the eggs, resulting in increased fry mortality. Bacterial problems will occur vertically in the eggs of breeding fish, resulting in increased mortality of fry until they are marketed. Bacteria will invade fish tissues through gills and cause infection, such as Streptococcus, Edwardsiella, Photobacterium, Nocardia, Vibrio alginolyticus and the sepsis caused by Vibrio parahaemolyticus is an important disease in the bacteria of melon larvae. Therefore, the purpose of this study is to analyze the main types of bacterial infection diseases and the seasons of occurrence in melon larvae, and to understand the incidence of various diseases through clinical symptoms, water quality testing, bacteriological isolation and identification of molecular biology strains, as a basis for future research. An important reference for farming management and disease prevention of aquacultured larvae. A total of 1588 cases were collected in this study from January 2019 to July 2022. According to the research and judgment results, the incidence rate of feeding management was 73.9% (1174/1588), the incidence rate of bacterial disease was 12.5% (198/1588), the incidence rate of parasitic disease was 6.5% (103/1588), and the incidence rate of normal disease was 5.4% % (85/1588), the incidence of unknown etiology was 1.7% (27/1588), and the incidence of viral diseases was 0.1% (1/1588). Among the identification results of bacterial pathogens, Streptococcus iniae accounted for 50.5% (100/198), Photobacterium dameslae subsp. damselae followed by 7.6% (15/198), Photobacterium dameslae subsp. piscicida 23.2% (46/198) Vibrio spp. 8.1% (16/198). With the fluctuation of the culture water temperature, the emergence of various pathogenic bacteria is at a suitable temperature, and the mortality rate of streptococcus, photobacteria and vibrio all increase significantly with the temperature change. The results of each bacteria are as follows: S. iniae 29.4 ± 2.63, P. piscicida 27.7 ± 3.37, Vibrio spp. 26.4 ± 4.3, P. dameslae 25.8 ± 2.36. According to the test results of water quality in different breeding periods and the drug susceptibility test results of different pathogenic bacteria, when the nitrous acid in the pond water is higher than the normal value in the later stage of breeding, the antibiotics used for the larger larvae are more resistant to antibiotics, and they can be selected for the market. Long-term drug treatment options are limited. The results of comprehensive aquaculture water temperature, pathogenic bacteria isolation rate and fish mortality analysis showed that in seasonal changes, small diseased fish were more likely to cause pathogen invasion and death; medium and large diseased fish mainly had increased mortality when the water temperature turned cold. Streptococcus, Photobacillus, and Edwardsiella infection occur in all stages of the breeding period, but Nocardia, Vibrio, and complex infections are mostly in the adult fish stage. Based on the results of this study, we found that the total isolation rate of bacterial pathogens in larvae tended to increase, and it was indeed positively correlated with changes in water environment temperature. The decomposition rate of cocci is also higher, and luminescent bacteria are the main bacterial pathogens isolated during the winter period. Moreover, some drug-resistant strains have appeared in the test results of the two antibiotic paper tablets. It is still quite difficult to treat the continuous intensive farming of this fish species in the future and the effectiveness of the treatment of bacterial diseases.
參考文獻
陳郁涵。飼料中不同蛋白質的質與量對四指馬鮁幼魚成長及體組成之影響。碩士論文。國立臺灣海洋大學水產養殖學系。 2020 。
鄭石勤。午仔魚的崛起與挑戰上 。養魚世界，第 42 卷，第 11 期， 31-35 。2018 。
謝嘉裕。 午仔魚養殖健康管理。財團法人台灣養殖漁業發展基金會。2019 。
Abu Hena MK, Idris MH, Wong SK , Kibria MM. Growth and survival of Indian salmon Eleutheronema tetradactylum (Shaw, 1804) in Brackish Water Pond. J of Fish and Aqua Sci, 6 , 479-484 , 2011.
Agnew W, Barnes AC. Streptococcus iniae : An aquatic pathogen of global veterinary significance and a challenging candidate for reliable vaccination. Vet. Microbiol 122, 1-15 2007.