Pathological and Microbiological Investigations of Naturally Infected Rainbow Trout (Oncorhynchus mykiss) with Flavobacterium psychrophilum

Abstract

It was aimed to identify and evaluate the pathological and microbiological findings in rainbow trout naturally infected with Flavobacterium psychrophilum in two trout farms of Aydın and Muğla within this study. A total of 77 rainbow trout (Oncorhynchus mykiss) (weighing 1 ± 02 g and 5-6 cm in size) were collected from two separate trout farms. The most common lesion seen in macroscopic examination was petechial hemorrhages that formed on the skin in different parts of the body. In addition, skin erosion and ulcers, exophthalmus and periocular hemorrhages were observed in the eyes. Microscopically, erosive foci in some areas, and ulcers in which the destructions reached the muscle layer in some areas were noted. There were bacteria clusters, hemorrhages and inflammatory cell infiltrations consisting of macrophages and lymphocytes in the ulcer foci. As a result of the bacteriological examination, the isolated bacteria were identified as Flavobacterium psychrophilum based on their morphological and biochemical character.

Keywords

• Flavobacterium psychrophilum,pathology,microbiology,rainbow trout,natural infection

Flavobacterium psychrophilum ile Doğal Enfekte Gökkuşağı Alabalıklarında (Oncorhynchus mykiss) Patolojik ve Mikrobiyolojik İncelemeler

Abstract

Bu çalışma ile Aydın ve Muğla illerinde bulunan iki alabalık işletmesinde Flavobacterium psychrophilum ile doğal enfekte gökkuşağı alabalıklarında şekillenen patolojik ve mikrobiyolojik bulguların tanımlanarak birlikte değerlendirilmesi amaçlanmıştır. İki ayrı alabalık işletmesinden toplanan 1±02 g ağırlığında ve 5-6 cm büyüklüğünde toplam 77 adet gökkuşağı alabalığı (Oncorhynchus mykiss) incelendi. Makroskobik incelemede en yaygın görülen lezyon, vücudun değişik bölgelerinde deride şekillenen peteşiyel kanamalardı. Buna ek olarak, deride erozyon ve ülserler, gözlerde ekzoftalmus ve perioküler kanama görüldü. Mikroskobik olarak, bazı alanlarda epidermisin yüzeysel olarak yıkımlandığı eroziv odaklar, bazı alanlarda ise yıkımlanmaların kas tabakasına dek ulaştığı ülserler dikkati çekti. Ülser odaklarında bakteri kümeleri, kanamalar ile makrofaj ve lenfositlerden oluşan yangısal hücre infiltrasyonları mevcuttu. Yapılan bakteriyolojik inceleme sonucu, izole edilen bakteri morfolojik ve biyokimyasal karakterine göre Flavobacterium psychrophilum olarak identifiye edildi.

Keywords

• Flavobacterium psychrophilum,patoloji,mikrobiyoloji,gökkuşağı alabalığı,doğal enfeksiyon

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