A survey on some risk factors and evaluation of their impacts on streptococcosis in rainbow trout farms in some provinces in Iran (Mazandaran, Fars)

One of the most important bacterial fish diseases which has caused some outbreaks in rainbow trout farms in Iran is streptococcusis. The farmers were suffering from huge economic losses due to the disease outbreaks in different rainbow trout farms in Iran. The aim of our study was to determine rate of streptococcusis incidence in different stage of growth in farmed rainbow trout in Mazandaran and Fars province. Fish and water samples were randomly collected and measured randomly in selected farms, monthly throughout a year. After clinical observations, Isolation and recognition of strep strains were made using biochemical and molecular tests. Some Environmental factors include Nitrate, Nitrite, Temperature, pH, Ammonia and DO measure during sampling periods. According to our results incidence of disease in juvenile is more than growers. Some samples showed clinical signs of streptococcusis without strep. contamination. Main isolated strain were S. iniae and S. garviea and S. uberis recognized for first time in east of Mazandaran province (Haraz River). Incidence of streptococcusis in rainbow trout affected by fluctuation of Nitrite, temperature and DO. Management of these factors can decrease rate of disease outbreaks

Growth Performance, Hemato-Immunological Responses, and Digestive Enzyme Activities in Silvery-Black Porgy (Sparidentex hasta) Fed Dietary Bovine Lactoferrin

An 8-week study was conducted to evaluate three different diets supplemented with bovine lactoferrin (LF) at 0 (control), 800, and 1200 mg LF kg−1 diet on somatic growth, hemato-immunological parameters, antioxidant status, and digestive enzyme activities in silvery-black porgy (Sparidentex hasta) juveniles. Fish fed the 800 mg LF kg−1 diet had higher growth performance and feed utilization parameters than the other groups. Hematological and liver antioxidant parameters were not affected by dietary LF supplementation. Fish fed the 800 mg LF kg−1 diet had higher plasma lysozyme activity values than the other groups. Total protease activity was higher in fish fed LF-supplemented diets than the control group. Results indicated that diet supplemented with 800 mg kg−1 for 8 weeks enhanced somatic growth performance, lysozyme activity, and proteolytic digestive enzyme activities in S. hasta, as well as improving feed efficiency parameters like the protein efficiency and feed conversion ratios.info:eu-repo/semantics/acceptedVersio

Study and evaluation of economical and hygienic effects of aflatoxin B1 in cultured Huso huso

In the present study, the impacts of various concentrations of Aflatoxin B1 (AFB1) on Beluga, Huso huso, under controlled conditions were investigated. Belugas (120±10 g) were fed diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed that various levels of AFB1 do not significantly affect the specific growth ratio (SGR) (p< 0.05) of fish in different treatments. However, weight gain and food conversion ratio (FCR) varied significantly (p< 0.05 between control and treatments with diets contaminated with 75 and 100ppb AFB1/kg after 90 days). The increase in level of AFB1 did not affect the percent of survival rate (SR) and no mortality was observed in treatments (SR=100%). Various levels of AFB1 under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SGR. Histopathological studies showed that different level of AFB1 can cause broad range of changes in liver, kidney, spleen and gills tissues, particularly at concentration of 75 and 100 ppb AFB1/kg of diets after 60 days. No tumor formation observed. With regard to toxin concentration and time of exposure to AFB1 in experimental fish, different degree of skin lesions (simple hemorrhage to progressive wounds) were observed in different parts of body especially in vent, caudal peduncle, fins, and head. "Yellow sores" on head and trunk regions are considerable and led to deterioration of appearance. Prevalence of skin lesion in different treatments was 8 -53.3 %, which after stop feeding with toxic diets, 16-24 % healing observed. Haematological changes included chronic anemia and lymphocyteopenia. Also neutrophilia observed with increasing of skin lesions. Meat accumulation of AFB1 in different treatments is not so considerable and harmful for human consumption, but is significantly different with control fishes (P<0.01)

Dietary soybean lecithin affects growth performance, fillet biochemical composition and digestive enzyme activity in Sparidentex hasta juvenile

An eight-week study was conducted on silvery-black porgy (Sparidentex hasta) juveniles to evaluate four isoproteic, isolipidic and isoenergetic different diets (50% crude protein, 20% crude lipids, 18.5 MJ kg−1) containing graded levels of soybean lecithin (SBL) (0, 30, 60 and 90 g kg−1 diet) at the expense of fish oil (FO). Fish fed the 60 g SBL kg−1 diet had significantly higher weight gain (32.4%) and feed intake (8.8 g fish−1) than the control group (SBL 0) (P < 0.05). The fillet fatty acid (FA) profiles were correlated with the FA profile of the experimental diets. Fish fed with SBL-supplemented diets had higher fillet phosphatidylcholine levels than the control group (P < 0.05). Plasma total immunoglobulin was higher in fish fed 60 and 90 g SBL kg−1 diets than in the other groups (P < 0.05). Total protease activity was higher in fish fed the 90 g SLB kg−1 diet than other treatments (P < 0.05). Results indicated that substitution of dietary FO with SBL diet up to 67% (60 g SLB kg−1 diet) improved somatic growth performance and profoundly affected the fillet fatty acid profile in silvery-black porgy juveniles