Temporal and spatial variations in percentage cover of macroalgae on rocky shores in South of Caspian Sea (Astara to Babolsar)

The most important primary producers of rocky shores are macroalgae. The present study investigated the temporal–spatial changes, the percentage of coverage and the influence of abiotic factors on macroalgae on rocky shores of southern Caspian Sea. Ten sampling stations were selected in the natural and artificial rocky shores from Astara to Babolsar. Sampling lasted for one year and took place every 2 months from September 2013 to July 2014 using a 50×50 quadrate sampler. Epibenthic macroalgae consisted of 2 genus, Cladophora and Entromorpha, from green algae and one genus, Laurenica, from red algae. The average water temperature, salinity, pH, dissolved oxygen and water conductivity were 16.48 °C, 9.87ppt, 8.27, 9.89 mg/l and 16.52 m/s, respectively. According to the results, the maximum algal coverage was observed in September (70.50 %) and the minimum coverage was observed in January (21.50 %). Results of one-way ANOVA indicated that the mean of algal coverage in various months of the year were significantly different (P<0.05). One-way ANOSIM ecosystem similarity test indicated that the coverage rates of the stations were homologous and similar. The results also showed that temperature has a significant effect on macroalgae coverage ratio on rocky shores in the southern Caspian Sea

Effects of different dietary energy levels on growth performance and sexual gonads development of Beluga (Huso huso) reared in brackish water

Culture of beluga (Huso huso) in new conditions such as inland brackish water necessitates studying nutritional requirements and effects of different diets on gonadic and somatic growth as well as physiological condition. In this research 74 beluga each 4 years old cultured in brackish water of earthen ponds in Bafgh Fisheries Research Station, were selected and distributed in 8 circular cement ponds. Feeding was done in 4 formulated diets with fixed protein level and 4 energy levels (400, 425, 450, 475kcal/l00g). Samples were biopsied at the start and the end of the experiment to determine sexuality and stage of maturation. To study gonad tissues, the hematoxylin-eosin method was used. Results indicated that somatic and gonadic growth indices were affected by diets. Somatic growth overlapped in both sexes. Sexual maturation stages were not the same in males and females and transition from stage II in males was more rapid than females. Considering the results in this study, diet treatments influenced on somatic growth in both sexes and gonadic growth in females. We conclude that somatic and especially gonadic growth in brackish water is suitable. Therefore, inland brackish water environment can be regarded suitable for beluga cultivation

Logistic regression of some risk factors underlying the outbreak of streptococcusis in rainbow trout (Onchorhynchus mykiss) farms in Haraz River, Mazandaran Province, Iran

Streptococcusis is the one of the most important bacterial fish diseases with outbreak in rainbow trout farms in Iran. The fish farmers have been largely suffered from huge economic losses due to the Streptococcusis outbreaks in different rainbow trout farms in Iran. The present study assessed the effects of some environmental risk factors on incidence of streptococcusis in rainbow trout farms in Haraz River in Mazandaran Province, Iran. A suit of environmental factors including water temperature, nitrite, nitrate, ammonium, water turbidity, DO, water Debi and total count of bacteria were explored as influential factors. Fish and water samples were randomly collected from 10 farm on a monthly basis throughout a year. Isolation and recognition of strep strains were made using biochemical and PCR tests and the data were analyzed by logistic regression method. According to the results, 20% of the differences were explained by the logistic model. Management of these factors might decline the rate of disease outbreak

Evaluation inhibitory effect of essential oil Savory (Satureja hortensis) in food fish

Aflatoxins are a group of fungal metabolites that are produced by the growth of fungi on food. These toxins cause illness in animals and humans, and are important in economic and humans health. In this investigation, inhibitory effects of savory (Satureja hortensis L.) essential oil were evaluated on the growth of Aspergillus flavus in fish food. A gas chromatograph apparatus linked to a mass spectrometer (GC/MS) was used to identify the effective components in Satureja hortensis essential oil after extraction. Essential oils against Aspergillus flavus incubated in PDA media and antifungal properties of essential oil Satureja hortensis was investigated. About of 300g of food samples was weighted and samples were sterilized by autoclave. Fungal suspension (3cc) was spraied into the feed samples, and various concentrations of essential oils (0, 300, 400, 500, 600ppm) added to samples. The samples were incubated at temperature of (±SD) 28±2°C. After 20-40 and 60 days period, randomly, some sampled were taken from containers and the production of aflatoxin B1, B2, G1, and G2 was measured in the laboratory. This result confirms that 500ppm concentrations of oil savory have antifungal properties against Aspergillus flavus

Oral recombinant bovine somatotropin improves growth performance in rainbow trout (Oncorhynchus mykiss)

The aim of this research was to evaluate the effects of oral recombinant bovine somatotropin (RBS) 1% on growth performance of rainbow trout (Oncorhynchus mykiss). 600 rainbow trout weighing 46±1 grams were randomly allotted in two groups including: 1) the control group and 2) RBS treated group, each in three replicates. The fish were hand-fed with commercial pellets. The fish received 200g RBS 1% per 100kg BW. The administration method of RBS-mixed feed to fish was once a week for 4 consecutive weeks, totally 8 times for 12 weeks of rearing periods. At the end of each rearing periods (on day 28, 56, 84) the means of some of growth characteristics were calculated in the control and RBS treated groups. The obtained results in this research demonstrated that there were no significant differences between appearance growth characteristics in the control and RBS treated groups on days 28 and 56 of rearing periods (p> 0.05). However, there were significant differences between means of whole body weight (p< 0.0 5), weight gain (p< 0.05), average daily growth ( p< 0.05) , total length ( p< 0.001) , and average daily length ( p<0.05 ) of the control and RBS treated groups on day 84 of rearing period. In the same period, there was greater 11.2% comparative growth rate in RBS treated group than the control group. Generally, the obtained data showed that oral administration of RBS 1% can produce a significant increase in the growth rate of rainbow trout weighing 46±1 grams on day 84 of rearing period

Assesses the economic and hygienic effects of aflatoxins in some of farmed fish and shrimp

Acipenser stellatus and Huso huso are the most important native sturgeon species in Caspian Sea. 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 tumour 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 chenges included chronic anemia and lymphocytopenia.Also nutrophilia observed with increasing of skin lesions. Meat accumulation of AFB1 in different treatments is not so considerable and harmfull for human cunsumption, but is significantly different with control fishes(P<0.01) Responses of experimental fishes to varying concentrations of aflatonix were investigated under controlled conditions. Fishes were fed diet containing 0, 25, 50, 75 and 100ppb AFB1/kg of diet for 3 months. Skin lesions evaluated through clinical observations. With regard to toxin concentration and time of exposure to AFB1 in experimental fish, different degree of skin lesions were observed in different parts of body. Histopathological changes in liver, kidney, spleen and gills of fish fed different level AFB1 and very wide range from congestion to necrosis. Progressive fat deposition, hepatocyte degeneration and necrosis in liver, especially in concentration 75 and 100 AFB1/kg of diets after 4o days of feeding, emphasize the mentioned results .At the end of the 30 days exposure period , blood samples were taken from the control and experimental fish. Blood was assayed for selected haematological parameters (haematocrit, hemoglobin, red blood cell count, white blood cell count, total albumin, total albumin, ALT and AST).The derived haematological indices of MCH, MCVand MCHC were calculated. Alterations in serum levels of ALT and AST are liver specified and the significant reduction in total protein and albumin content observed in some experiments.There was no significant difference in SGR between experimental treatments but some differences observed in GR and FCR

Effects of temperature on hematological and histopathological changes and survival rate of juvenile Fenneropenaeus vannamei experimentally challenged to White Spot Virus

Many shrimp farmers were suffering from White Spot Disease (WSD) onset in last decades. Oscillation of environmental factors could lead mortality in susceptible hosts. Our study was aimed to investigate the effect of different temperatures on juvenile Fenneropenaeus vannamei experimentally exposed to White Spot Virus (WSV). Five hundred and forty juveniles were distributed among 3 treatments in triplicates, 22, 25 and 30°C and experimentally WSV were injected in the shrimps. Our results showed mortality started at 36 h post inoculation (hpi) in the treatment at 25°C (T25), meanwhile the mean value of mortality percent at 54 hpi in T25 (71.10±17.35) showed the significant difference (p=.045) with T22 (3.33±3.33) and T30 (Not Observed, NO.). Our results suggest that in site selection, in primary stage of farm designing, water temperature at more than 29°C, should be considered as key environmental factor. This finding can lead us that why the White Spot Disease occurred with high mortality in some area when the days of shrimp culture were prolonged until mid autumn

Effects of aflatoxin B1 on growth performance, health indices, phagocytic activity and histopathological alteration in Fenneropenaeus indicus

Mycotoxins contamination of feedstuff for aquatic animals is common in regions with humid tropical conditions. In this study Indian white shrimp, Fenneropenaeus indicus, (11.79 ± 1.76 g) were fed with diets containing 0, 20, 50, 100, 200, 400, 800 and 1600 ppb levels of aflatoxin B1 (AFLB1) for 8 weeks. Final weight, aflatoxin B1 residue (2-week intervals), Total Hemocyte Count (THC), Total Plasma Protein (TPP), Phagocytic Activity (PA), Survival rate (4-week intervals) were determined. Histopathological alterations in hepatopancreas, midgut and muscle tissues were studied at the end of 4 and 8 weeks. Shrimps fed with the 1600, 800 and 400 ppb concentrations of AFLB1 exhibited slow growth, and more reddish discoloration disseminated over the body at 4th week. Growth parameters, survival rate and health indices (THC, TPP) of F. indicus, are affected by the different doses of AFLB1 in diets. At the end of 8th week, doses of AFLB1 in the diets showed negative correlation to final weight, survival rate, THC and TPP (r = - 0.312, -0.603, -0.237 and - 0.649 at P<0.001, respectively). Moreover, significant histopathological alterations in the hepatopancreas, midgut and muscle tissues of exposed shrimps to different levels of AFLB1 were observed and these alterations are obviously indicated by changes in the health indexes (THC and TPP)

Effects of different dietary levels of AFB1 on survival rate and growth factors of Beluga (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±10g) were fed on diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed 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) were varied significantly (P<0.05 between control and treatments with diets contaminated with 75 and 100 ppb AFB1/kg after 90 days). The increase AFB1 level of did not affect on the percent of survival rate (SR) and no mortality was observed in treatments (SR=100%) suggesting that various AFB1 levels under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SR and SGR. Histopathological studies showed that different level of AFB1 can cause broad range of change in liver tissue, including progressive fat deposition, hepatocyte degeneration and necrosis, particularly at concentration of 75 and 100 ppb AFB1/kg of diets after 60 days

Study on nutrition requirements and effect of different diets on gonadic and somatic growth of beluga (Huso huso) in new condition such as inland brackish water

Taking into consideration culture of beluga (Huso huso) in new condition such as inland brackish water, it is very important to study nutrition requirements and effect of different diets on gonadic and somatic growth as well as physiological condition. In this research 74 beluga (4 years old) cultured in brackish water earth ponds in Bafgh fisheries research station, were selected and distributed in 8 circular cement ponds. Feeding was done in 4 formulated diets with fixed protein level and 4 energy levels (400,425,450,475 kcal/100gr). Samples were biopsied in the first and the end of experiment to determine sexuality and stage of maturation. To study gonad tissues, the hematoxylin-eosin method was used. Results indicated that somatic and gonadic growth index was affected by diets. Growth somatic overlapped in both sexes. Sexual maturation stages were not the same in both males and females and transition from stage II in males was more rapid than females. Considering the results in this study, diet treatments influenced on somatic growth in both sexes and gonadic growth in females. It seems to state of somatic and especially gonadic growth in brackish water is suitable. Therefore, inland brackish water environment can be introduced as a suitable environment cultivation of beluga