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This study was conducted to determine antibiotic susceptibility of Flavobacterium psychrophilum isolated in diseased rainbow trout (Oncorhynchus mykiss) from two hatcheries in the Mediterranean region of Turkey. The samples were taken from the kidney and spleen for bacteriology from rainbow trout juveniles (weight 0.7-1 g) in April and isolates obtained on tryptone yeast extract salts (TYES) agar medium at 15°C for 72 hours. Fourteen isolates were identified as F. psychrophilum using biochemical, physiological, and morphological characteristics and API ZYM test. Antibiotic sensitivities of the isolates were determined by the disc diffusion method on TYES agar, and the results were evaluated according to CLSI standards. Only one isolate from each hatchery was used for the antibiogram test. Both isolates were sensitive to amoxicillin/clavulanic acid 2:1, penicillin, nitrofurantoin, florfenicol, amoxicillin, clindamycin, chloramphenicol, ampicillin, doxycycline, streptomycin, and erythromycin; resistant to sulfadiazine, sulfamethoxazole/trimethoprim, oxolinic acid, vancomycin, trimethoprim/sulfadiazine, gentamicin, kanamycin, nalidixic acid, oxacillin, enrofloxacin, flumequine, tobramycin. The results show that isolating F. psychrophilum and performing the antimicrobial susceptibility testing is important issue in disease control.

The aim of this study was to determine the immunostimulant effects of geophyte plant extract on non-specific defence mechanisms of rainbow trout (Oncorhynchus mykiss). For this purpose, Muscari comosum was collected in Muğla region and extracted in ethanol. Then, The plant extract applied into fish by intraperitonal injection in two different concentrations (0.5mg/ fish and 2.0 mg/fish). The average fish weight was 140 g. Following the injection on the 1st, 7th, 14th, 21st, 28th days the blood and serum samples were collected from fish in each group and examined for various parameters including percentage of hematocrit, the counts of nitroblue tetrazolium (NBT) positive neutrophils, total leukocyte counts, percentage of white blood cells and serum lysozyme activity. The results indicated that the counts of NBT (+) neutrophils, percentage of monocyte and neutophil and total leukocyte counts increased in the group with injected 0.5mg plant extract /fish compared to control group (P

A study was conducted to determine the effect of feeding with diets containing kefir on growth performance and fatty acid profile of rainbow trout (Oncorhynchus mykiss). Four isonitrogenous (450 g protein kg−1) and isocaloric (4325 kcal kg−1) diets were prepared in trout feed to contain 0 (control), 20, 50 and 100 g kg−1 kefir. Fish, initial weight of 46 g, were randomly distributed into triplicate 520-L fibreglass tanks in freshwater flow-through system. Fish were fed at 4% of the body weight thrice a day for 12 weeks. The results indicated that survival rate ranged from 97.14 to 100% without significant difference among treatments (p > .05). Whole-body moisture and lipid composition were significantly affected by diets containing different levels of kefir (p

In this study, juvenile rainbow trout fed with commercial pellets containing kefir provided increased nonspecific immune response and improved disease resistance against lactococcosis and yersiniosis. Kefir was used as a feed supplement at 2, 5, and 10% inclusion rates and several nonspecific immune parameters were observed at day(s) 1, 7, 14, 21, 28, and 35 following the treatment. A total of four experimental groups, including control, was established. The various parameters including hematocrits, nitroblue tetrazolium positive neutrophils, total leukocytes, serum lysozyme activity, total serum protein, and immunoglobulin M (IgM) levels were examined. As a result of this study, kefir-fed fish had an increase in measured nonspecific immune parameters, especially in the group received the 10% kefir treatment. The challenged fish fed with kefir-supplemented diet showed a better survival rate against Lactococcus garvieae than Yersinia ruckeri. Kefir supplementation reduced fish mortality significantly against L. garvieae.

In this study, we isolated Candida sp. for the first time from fry of rainbow trout ( Oncorhynchus mykiss ) in Turkey. Candida species caused disease in fry (average 0.2 g) which was observed at 10°C water temperature in February 2016. Due to yeast accumulation on gills, whitish areas was seen and fusion of secondary lamella in gills were observed under microscope. The microbiological samples of kidney, spleen and gills were streaked onto trypticase soy agar (TSA) and tryptone yeast extract salts ( TYES ) agar plates and incubated at 22°C in TSA and 18°C in TYES agar for 48 h. Thirteen isolates were obtained and Gram staining was performed. The all of the isolates were determined as yeast cell based on cellular morphology by using light microscopy . The identification was performed by ITS (Internal transcribed spacer) region sequence analysis and sequence data demonstrated that representative isolate D11 belonged to genus Candida . The yeast infection might have seen in early development stages (larvae and fry) due to the intensive antibiotic use against rainbow trout fry syndrome (RTFS) disease.

In this review, Our aim was to determine different aspects of the most threatening bacterial diseases of rainbow trout culture in freshwater systems. In Turkey, aquaculture has started in the 1970s by farming the rainbow trout. It is one of the most important freshwater species. The recent knowledge about the value of production of rainbow trout in our country found to be 111, 335 tons in 2012 and 122,873 tons in 2013 which showed an increasing trend until 2014 by each year. Depending upon the production in intensive culture of fish has led to outbreaks of some bacterial diseases which causes economical losses in trout farms. The most important bacterial diseases reported as yersiniosis, vibriosis, motile Aeromonas septisemia, lactocococosis, flavobacteriosis. We obtained a review of the literature that focuses on the bacterial diseases which have been reported as outbreaks in rainbow trout farms up to now. When the reports evaluated Flavobacterium psyrophilum found to be most pathogenic bacteria in the rainbow trout hatcheries. The current studies on developing a vaccine and vaccination methodology to be able to prevent bacterial diseases are also addressed.

In this study, a new trivalent vaccine was developed and evaluated the efficacy with adjuvants (Freund’s Complete Adjuvant and glucan) and non-adjuvanted vaccine in rainbow trout(20g) against to pathogens; L. garvieae, V. anguillarumand Y. ruckeri. For this purpose, four experimental groups were formed including control. The vaccine was prepared formalin-killed bacteria and then combined with adjuvants that were given into fish by intraperitoneal injection. Control fish were received only phosphate buffered saline-PBS. A booster was applied the fish which were vaccinated with a nonadjuvanted vaccine 21 days post-injection. All the groups were challenged against three pathogens at day 30, 90, 120 and 270 post vaccination. The results showed that fish had a high level of protection of pathogens in the vaccinated groups up to 9 months. The level of protection was calculated by obtaining the Relative Percent Survival (RPS). RPS was determinedas in the non adjuvanted plus a booster injected group: Y.ruckeri 96,77%, V.anguillarum 100%; L.garvieae 96,66%, Glucan: Y.ruckeri 93,54%; V.anguillarum 96,77%, L.garvieae 93,33 %, FCA :Y.ruckeri 100%, V.anguillarum 87,09 % , L.garvieae 93,33% at 270 day. The efficacy of the vaccine has been found to provide long-term protection against to three pathogens in the experimental condition.

In this study fish diseases and therapeutic purposes prophylactic widely used formalin (CH2O)'s in rainbow trout (Oncorhynchus mykiss) cortisol, glucose and their effects on lyso-zyme activity were examined. October-November 2009 the researches have been carried out among the 60 rainbow trout weighing approximately 180 g were used. Replications in the ex-periment conducted of formalin 250 mg/L (60 minutes), 500 mg/L (45 minutes) concentrations were applied. For each group of 20 fish, cortisol, serum glucose and lysozyme activity was used for measurements. Cortisol analysis ECLIA (Electro chemiluminescence Immun Assay) method, lysozyme activity diffusion agar (agar plate, lysoplate) with the method of analysis and glucose were determined by spectrophotometric methods. The data obtained in the experi-ment of the SPSS package statistical program to evaluate all the data using analysis of variance (ANOVA) was applied and the group mean differences between LS Means JMP Student's T test multiple comparison test with significance level according to p

The effectiveness of vaccine mixtures against lactococcosis was tested in rainbow trout (Oncorhynchus mykiss). The M1 strain of Lactococcus garvieae, isolated from a recent outbreak of lactococcosis at a rainbow trout farm in Turkey, was used in a trial comparing five immuniza- tion treatments: (a) formalin inactivated bacterin (vaccine), (b) the above bacterin together with Freund’s Incomplete Adjuvant (FIA), (c) the bacterin combined with β-glucan, (d) β-glucan only, and (e) phosphate buffered saline-PBS (control). Fish were given intrapritoneal injections and challenged by exposure to the bacteria 30, 75, or 125 days after vaccination. In fish exposed to the bacteria 30 days after injection, the relative percent survival (RPS) was 88.89% in the group that received only bacterin and 100% in the group that received the bacterin combined with FIA. Immunity remained high in the bacterin+FIA group, as the RPS in this group remained 100% in fish challenged at 75 days, significantly higher than in all other groups. In fish exposed to the bacteria 125 days after vaccination, the RPS was 54.55% in fish vaccinated with the bacterin only and 84.84% in fish vaccinated with bacterin+FIA. In the group that received only β-glucan, immunity did not improve after vaccination. Micro-agglutination tests of serums showed that immunized fish produced antibodies at high titers within 30 days. In short, the formalin-inacti- vated M1 strain provided longer lasting protection against Lactococcus garvieae in rainbow trout when combined with FIA than when administered alone or with β-glucan.

Formaldehit su urunleri sektorunde balik hastaliklarinin kontrolu ve dezenfektan olarak yaygin olarak kullanilmaktadir. Ancak, bu durum cesitli cevresel olumsuzluklara sebep olabildigi gibi, uygulama yapilan baliklarda da olumsuz etkilere neden olabilmektedir. Bu calismada 250 mg/L (1 saat) ve 500 mg/L (45 dk) konsantrasyonlarinda formaldehit uygulanmistir. Calisma sonucunda elde edilen histopatolojik bulgularda formaldehit uygulanan baliklarin solungac lamellalarda pilar ve epitel hucrelerinde dejenerasyon, interlamella alanlarda lenfoid ve mononukleer hucre infiltrasyonu ve nekroz, kas dokularinda dejenerasyon, karacigerlerinde genlesme, venalarinda konjesyon, damarlarda hasar ve hepatositlerde dejenerasyon belirlenmistir. Sonuc olarak formaldehit uygulamasinin gokkusagi alabaliklarinda histolojik olarak olumsuz etkilere neden oldugu gorulmustur. Bu nedenle su urunleri isletmelerinde bilincli ve ihtiyac dahilinde kullanilmasi gerektigi kanaatine varilmistir.