First Report of Chryseobacterium sp. from Koi (Cyprinus carpio) in Turkey

In this study, we isolated Chryseobacterium sp. from koi in Turkey. The disease outbreak occurred in fish weighing 10-300g (water temperature 9-10°C) in November 2011- February 2012. The cumulative mortality rate was approximately 55% over 4 months. Infected koi exhibited anorexia, weakness, emaciation, damage to dorsal and caudal fins, grey-white skin discoloration (1-1.5cm) in the head area, large open wounds in skin with disease progression, necropsy findings, paleness of the liver, enlarged spleen and kidney, acidic fluid in the body cavity. Samples for bacteriological examinations were collected from the kidney, liver, and spleen using sterile swabs; these samples were streaked onto Anacker ordal Agar and incubated at 18°C for 48 h. Five bacterial isolates were obtained from diseased fish. Phenotypic characteristics of the isolates were determined by conventional methods and rapid identification kits, API 20NE, and API ZYM. Comparative 16S rRNA gene sequence analysis demonstrated that isolate Sin57 belonged to the genus Chryseobacterium, with highest sequence similarity (98.5 %) to C. aahli T68T and C. limigenitum SUR2

Effects of Enzyme-Producing Probiotic Bacteria Isolated from the Gastrointestinal Tract of Trout on the Growth Performance, Survival, and Digestive Enzyme Activity of Rainbow Trout Fry (Oncorhynchus mykiss)

In this study, we investigated the effects of enzyme-producing probiotic bacteria isolated from the gastrointestinal tract of rainbow trout on the growth performance, feed conversion ratio, and digestive enzyme activity, of fry (Oncorhynchus mykiss). Three isolates (G8/2013, T7/2013 and U5/2013) of candidate bacteria elicited the highest protease, lipase, and amylase activities, respectively. Isolates were identified as Aeromonas sp., Bacillus sp. and Citrobacter braakii by morphological, physiological, biochemical characterizations as well as 16S rRNA gene sequence analysis. The fry basal diet was supplemented with probiotics at varying concentrations; G8 group, Aeromonas sp. 1.72 x 108 CFU/g; U5 group, Bacillus sp. 3.01 x 108 CFU/g; T7 group, C. braakii 2.96 x 108 CFU/g and a mixed group (same bacterial concentrations), and control group (no bacteria). The rainbow trout fry were fed ad libitum in triplicate treatments with supplemented and non-supplemented probiotic diets for 70-days. The total bacterial count in the intestine was significantly higher in the mixed group (30th and 50th days) and U5 group (50th and 70th days) compared with the control group. However, there was no significant difference in weight gain, specific growth rate (SGR), feed conversion ratio (FCR), nutrient digestibility, or digestive enzyme activity among the groups.

New rRNA primers for the detection of Vibrio anguillarum

In this work, 51 V. anguillarum isolates (42/51 of O1 serotype, 9/51 of O2) obtained from cultivated marine fish by Avsever and Ün (2015) were used. These isolates were confirmed with universal primers specific to amiB genes. They were also detected successfully at a rate of 100% with a new primer couple designed according to 16S ribosomal RNA sequence. The new primers were found to have a high sensitivity and specificity but were liable to give a cross-reaction with Vibrio ordalii

Isolation and Characterization of Potential Probiotic Bacteria from Rainbow Trout Oncorhynchus mykiss, (Walbaum) Rearing Units Against Bacterial Pathogens

Bacteria were studied for potential probiotic activity against vibriosis, yersiniosis and lactococcosis in rainbow trout. A total of 79 bacterial strains were isolated from rainbow trout rearing water, and screened for antagonistic activity against Vibrio anguillarum, Yersinia ruckeri and Lactococcus garvieae using a well-diffusion agar assay. Vibrio spp. showed inhibitory activity against V. anguilarum and L. garvieae, while Aeromonas spp. displayed antagonistic activity against L. garvieae. Antagonistic L. garvieae strains displayed inhibitory activity against all pathogens. Antagonistic strains were characterized for enzymatic activity (protease, lipase) and hydrophobicity. Vibrio sp. A12, and Aeromonas sp. A5, G1, were found to have enzymatic properties and hydrophobicity. L. garvieae strains showed weak hydrophobicity and did not display enzymatic activity. Phenotypic characteristics of antagonistic strains were determined by conventional API 20NE and API STREP rapid identification systems. Antagonistic L. garvieae strains were confirmed as L. garvieae by PCR using species-specific primers. Candidate probiotic strains were tested for pathogenicity in rainbow trout by intraperitoneal injection. Following a challenge, L. garvieae strains caused mortality and were eliminated from further study. As a result, Aeromonas spp. and Vibrio spp. were identified as probiotic candidates with the potential to control vibriosis and lactococcosis

Türkiye’nin Orta Karadeniz Bölgesindeki gökkuşağı alabalıkları (Oncorhynchus mykiss, Walbaum, 1792)’nda laktokokkozis ve Lactococcus garvieae etkeninin antimikrobiyal duyarlılığı

"In this research study, we isolated Lactococcus garvieae from rainbow trout in the middle Black Sea region in Turkey. The diseases outbreak occurred at average water temperature of 16.7°C during April-May 2009. Clinically stagnation, inapetence, darkening of the skin, exophtalmia, opacification in the cornea, hemorrhages in the eyes and at the base of pectoral and anal fins, swollen abdomen and wounds on the body surface were observed in infected fish. In necropsy; the existence of accumulation of bloody fluid in the body cavity, ascites in the intestines and the stomach characterized with a yellowish-colored liquid, enlarged and darkening in the spleen and kidney, fading in colour, existence of petechial hemorrhages and enlarged in the liver were detected. In order to isolate the aetiological agent, 20 infected rainbow trout weighting between 50-100 gr were used. As the result of conventional tests used in the identification of the bacteria, the aetiological agent was identified as L.garvieae. The isolated L.gavieae strain was determined as susceptible to amoxicillin, amoxicillin/clavulanic acid, cephalothin, chloramphenicol, doxycycline, enroflaxacin, pristinamycine and tetracycline."Bu çalışmada, Türkiye’nin Karadeniz Bölgesindeki gökkuşağı alabalıklarından Lactococcus garvieae izole edildi. Hastalık salgını ortalama 16.7°C su sıcaklığında Nisan-Mayıs 2009 aylarında görüldü. Hasta gökkuşağı alabalıklarında klinik olarak durgunluk, iştahsızlık, renkte koyulaşma, tek ya da çift taraflı eksoftalmus, korneada opaklaşma, gözlerde, pektoral ve anal yüzgeç tabanlarında hemoraji, karında şişkinlik, vücut yüzeyinde yaralar görüldü. Nekropside vücut boşluğunda kanlı-renkli bir sıvının varlığı, barsak ve midede sarı berrak renkte sıvı ile karakterize asites, dalak ve böbrekte büyüme, renklerinde koyulaşma, karaciğerde büyüme, renginde açılma ve peteşiyel kanamaların olduğu tespit edildi. Hastalık etkenini izole etmek için yaklaşık 50-100 g ağırlığında hasta 20 adet gökkuşağı alabalığı bakteriyolojik incelemelerde kullanıldı. Bakterilerin identifikasyonunda konvansiyonel testler kullanıldı ve hastalık etkeni L.garvieae olarak tanımlandı. İzole edilen L.garvieae suşu, amoxicillin, amoxicillin/clavulanic acid, cephalothin, chloramphenicol, doxycycline, enroflaxacin, pristinamycine ve tetracycline duyarlı olduğu tespit edildi

Vagococcus salmoninarum, a causative agent of disease in rainbow trout ( Oncorhynchus mykiss, Walbaum) broodstocks in the aegean region of Turkey

In a commercial rainbow trout farm located in the Aegean region of Turkey, a disease outbreak with an aver- age mortality of 10% was recorded in rainbow trout broodstocks. The disease symptoms emerged at 10-12;deg;C water tem- perature after spawning periods. 6 bacterial isolates were obtained from 2 of the clinically infected rainbow trout brood- stock. These isolates were observed to be Gram-positive cocobacilli and were identifed phenotypically as Vagococcus salmoninarum . Isolates were also confrmed by using a PCR method with V.salmoninarum specifc primers. Antibiotic susceptibility of strain VG3 was assessed by the Kirby-Bauer disk diffusion method, and the results showed that it was susceptible amoxycillin, ampicillin, enrofoxacin, norfoxacine, oxolinic acid and forfenicol. V.salmoninarum isolates isolated from different geographical region in Turkey were revealed to be related (0.73) as a result of ERIC-PCR.Türkiye’nin Ege Bölgesi’nde yer alan ticari bir alabalık çiftliğinde gökkuşağı alabalığı anaçlarında görülen bir hastalık esnasında ortalama %10 oranında bir ölüm kaydedildi. Hastalık belirtileri yumurtlama sonrası 10-12°C su sıcaklığında görüldü. Klinik olarak enfekte 2 anaç balıktan 6 adet bakteriyel izolat elde edildi. Bu izolatların Gr (+) kokobasil oldukları tespit edildi ve fenotipik olarak Vagococcus salmoninarum olarak teşhis edildi. İzolatlar, aynı zamanda spesifik V. salmoninarum primerleri ile PCR metodu kullanılarak teyit edildi. VG3 suşunun antibiyotik duyarlılığı Kirby-Bauer disk difüzyon metodu ile belirlendi ve amoksisillin, ampisillin, enrofoksasin, norfoksasin, oksolinik asit ve forfenikole duyarlılık gösterdi. Türkiye’de farklı coğrafik bölgelerden izole edilen V. salmoninarum izolatlarının ERIC-PCR sonucuna göre ilişkili olduğu (0.73) görüldü