Trace elements in the muscle and liver tissues of Garra shamal from the freshwater ecosystem of Oman: an exposure risk assessment.

Anthropogenic activities lead to environmental contamination with foreign substances such as heavy metals. This work was aimed to monitor trace elements (total arsenic (As), cadmium (Cd), chrome (Cr), cobalt (Co), copper (Cu), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni), and zinc (Zn)) contamination levels (dry weight base) in three natural freshwater reservoirs of Oman including Al Khawd and Al Amarat (Muscat Governorate) and Surur area (Ad Dakhiliyah Governorate as control area) using a native benthic inland fish (Garra shamal; Cyprinidae) for the first time. The muscle and liver of a hundred and twenty G. shamal were collected to assess the degree of metal contamination. Atomic absorption spectrometry was used as an analytical technique. From the spectrum of analyzed elements, we found Zn as a major element in monitored areas. The statistically significant (P < 0.05) highest concentrations of Zn liver (0.275 ± 0.065 µg/g) were in Al Amarat compared to the other areas. The concentrations of monitored elements in the fish muscle were lower than the liver samples. Furthermore, the fish length was significantly correlated with the accumulation of Hg and Co in both muscle and liver samples. In all analyzed fish from Oman inland water, the concentrations of elements were below the permissible limits; however, additional research is needed.

Dietary Mentha piperita essential oil loaded in chitosan nanoparticles mediated the growth performance and humoral immune responses in Siberian sturgeon (Acipenserbaerii).

Siberian sturgeon (Acipenser baerii) fry often face environmental stressors that can compromise their immune system, rendering them susceptible to opportunistic pathogens in intensive aquaculture systems. In this study, we explored the innovative use of chitosan nanoparticles loaded with Mentha piperita essential oil (MPO/CNPs) as a dietary supplement to improve the growth and immune responses of A. baerii. The results demonstrated that the addition of MPO/CNPs to the diet led to significant improvements in growth, as evidenced by increased red blood cell count, hematocrit, haemoglobin concentration, and reduced triglyceride levels. Furthermore, significant differences were observed in the immune parameters for the treatment groups receiving Mentha piperita essential oil loaded in chitosan nanoparticles (MPO/CNPs), including enhanced lysozyme activity, immunoglobulin M (IgM) levels, respiratory burst activity, and ACH50 activity. Additionally, gene expression analysis revealed upregulation of key immune-related genes in the MPO/CNPs-treated groups. These findings suggest that the use of MPO/CNPs can enhance the growth and bolster the immune defences of Siberian sturgeon fry, contributing to more sustainable production in intensive aquaculture environments.

Trace elements in the muscle tissue of Hemiculter leucisculus and Abramis brama orientalis from the Anzali International wetland, south-west of Caspian Sea: An exposure risk assessment.

High levels of trace elements in aquatic environments can affect the quality of seafood. We analyzed the concentrations of As, Cd, Co, Hg, Mn, Ni and Pb, in the edible muscles of Hemiculter leucisculus and A. brama orientalis caught in four different areas of southwest of the Caspian Sea. We estimated the potential risks for human health deriving by the oral consumption of these two species, and the Target Hazard Quotient (THQ) according to the US-EPA approach. THQ by adults and children was always below 1 for all stations. The greater contribution was given by Co, followed by Cd, Hg, Pb, Ni, As and Mn. Total-THQ was 0.538 and 0.246 for children and adults, respectively. Trace elements detected by our study were not elevated, highlighting a positive picture of the studied area and a lower risk of developing chronic systemic effects deriving from the consumption of local fish products.

The Effect of Lactococcus lactis subsp. lactis PTCC 1403 on the Growth Performance, Digestive Enzymes Activity, Antioxidative Status, Immune Response, and Disease Resistance of Rainbow Trout (Oncorhynchus mykiss).

The effect of Lactococcus lactis subsp. lactis strain PTCC 1403 as a potential probiotic was investigated on the growth, hematobiochemical, immune responses, and resistance to Yersinia ruckeri infection in rainbow trout. A total of 240 fish were distributed into 12 fiberglass tanks representing four groups (× 3 replicates). Each tank was stocked with 20 fish (average initial weight: 11.81 ± 0.32 g) and fed L. lactis subsp. lactis PTCC 1403 at 0 (control, T0), 1 × 109 (T1), 2 × 109 (T2), and 3 × 109 (T3) CFU/g feed for 8 weeks. The results showed enhanced protein efficiency ratio and reduced feed conversion ratio in the fish-fed T2 diet. Further, fish-fed T2 and T3 diets showed a significantly higher survival rate than the control (p < 0.05). Trypsin, lipase, and protease activities were increased in fish-fed L. lactis subsp. lactis PTCC 1403 compared to the control (p < 0.05). Fish fed with a T2 diet showed significantly (p < 0.05) lower glucose content than other groups. The blood lysozyme activity and IgM showed significantly (p < 0.05) higher values in fish-fed T2 and T3 diets than in other groups. The antioxidative responses were increased in fish-fed T2 and T3 diets (p < 0.05). After 7 days post-Y. ruckeri challenge, the cumulative mortality rate showed the lowest value in fish fed with T1 and T2 diets, while the highest value was recorded in the control group. In conclusion, the results revealed beneficial effects of L. lactis subsp. lactis PTCC 1403 on the feed efficiency, immune response, and resistance to Y. ruckeri infection in rainbow trout.

Dietary Gracilaria persica mediated the growth performance, fillet colouration, and immune response of Persian sturgeon (Acipenser persicus).

Algal seaweeds have abundant amounts of active substances and can be used as pharmaceuticals and biomedicals in aquafeeds. In this context, the powder of red macroalgae Gracilaria persica was included in the diets of Persian sturgeon at the rate of 0, 2.5, 5, and 10 g/kg to investigate its role on the growth rate, fillet colouration, haemato-biochemical indices, serum, and skin mucus immunity. The weight gain, SGR, and FCR displayed no significant changes in fish fed varying levels of G. persica (P > 0.05). The level of total carotenoids was significantly higher in the blood and fillet of fish fed 5 and 10 g G. persica/kg diet (P < 0.05). Dietary G. persica significantly altered RBCs, WBCs, and HCT at 5, and 10 g/kg, whereas the Hb was increased in fish fed 5 g/kg (P < 0.05). The blood total protein and albumin were significantly increased in fish fed 5 and 10 g/kg (P < 0.05). No significant alterations were observed on ALT, AST, ALP, and glucose levels of fish fed varying levels of G. persica (P > 0.05). Serum Ig, lysozyme, superoxide dismutase, catalase, and respiratory burst activities were increased in fish fed 5, and 10 g/kg than fish fed 0 and 2.5 g/kg diet (P < 0.05). The level of total protein and lysozyme activity in the skin mucus were significantly higher in the blood and fillet of fish fed 5, and 10 g G. persica/kg diet than fish fed 0 and 2.5 g/kg (P < 0.05). Based on the obtained results, G. persica can be used as a feasible feed additive in the diets of Persian sturgeon at 5-10 g/kg diet.

Bioaccumulation of trace metals in banded Persian bamboo shark (Chiloscyllium arabicum) from the Persian Gulf: A food safety issue.

Persian bamboo shark (Chiloscyllium arabicum) was collected from two sites of the Khozestan province, northern basin of Persian Gulf, with the aim to identify differences in metal concentrations between fishing areas as well as the risk for human health due to consumption of the selected species. We analyzed Zn, Cu, Pb, Hg, Cd and Ni in muscle and liver tissues of specimens from both areas of study using atomic adsorption spectrometry. Statistical elaborations revealed higher bioaccumulation of metals in livers than muscle as well as in the site of worthy of Musa as regards Zn, Pb and Ni than the site of worthy of Darvis, due to the more intensive anthropogenic input. The risk for consumers is low for the most of metals, with the exception of the THQ for Hg, which resulted next to the level of risk with high frequencies of consumption.

Immunological responses and disease resistance of rainbow trout (Oncorhynchus mykiss) juveniles following dietary administration of stinging nettle (Urtica dioica).

The present study investigated the effects of dietary supplementation of stinging nettle (Urtica dioica) on growth performance, skin mucus, immune response and disease resistance of rainbow trout (Oncorhynchus mykiss) fed with diets supplemented with U. dioica at 0, 1, 2 and 3%. After 8 weeks of feeding, the addition of U. dioica at 3% level resulted in improved weight gain, specific growth rate and feed conversion ratio significantly when compared to the other groups (P < 0.05). Hematological responses including: hematocrit (Htc), hemoglobin (Hb), lymphocyte and neutrophil populations enhanced significantly in fish fed 3% of stinging nettle when measured after 4 weeks; while, total red blood cells, white blood, Htc, Hb, lymphocyte and neutrophil populations significantly increased after 8 weeks in the same group (P < 0.05). Total serum protein and glucose contents increased significantly in fish fed stinging nettle at 3% when compared to the other groups after 8 weeks; however, triglycerides decreased significantly in the same group on the 4th and 8th week (P < 0.05). Additionally, several immune parameters, namely, IgM, lysozyme, complement components C3 and C4, and respiratory burst of blood leukocytes significantly increased in the 3% fed group on the 4th week; while, after 8 weeks the immune responses enhanced in fish fed 2 and 3% diets (P < 0.05). At the end of the feeding trial, mucus samples obtained from the fish fed stinging nettle supplementation exhibited improved antagonistic activities against several bacterial pathogens (Streptococcus iniae, Yersinia ruckeri, Vibrio anguillarum and Lactococcus garviae), skin mucus enzymes activities (alkaline phosphatase, lysozyme, protease and esterase) and protein levels in 2 and 3% groups with the highest being in case of 3% group when compared to the other groups (P < 0.05). The cumulative mortality of rainbow trout subjected to Y. ruckeri infectious exhibited relatively low mortality levels in all supplemented groups with the lowest being in fish fed 3% stinging nettle. The present findings demonstrated that dietary administration of U. dioica enhanced growth and stimulated fish immunity; thus, enabling the fish to be more resistant against bacterial infections.

A comparative study of inorganic elements in the blood of male and female Caspian pond turtles (Mauremys caspica) from the southern basin of the Caspian Sea.

Due to their bioaccumulation and biomagnification pathways, inorganic elements can accumulate in high-level aquatic organisms in the food web. Then, this species can be used to monitor the quality of the environment. Blood concentration of nine inorganic elements, including possible toxic metals (An, Cu, Mn, Se, As, Ni, Cd, Pb, and Hg), in 20 males and 20 females from eight different locations with high industry and agriculture activities in Iran were evaluated in this work. Additionally, size, sex, condition index, and locations were also included and analyzed. Among the essential elements, Zn and Se presented very high concentrations (56.14 ± 2.66 and 8.44 ± 0.77 µg/g ww, respectively) in all locations. Regarding possible toxic elements, Pb and Cd presented concerning concentrations as well (0.52 and 0.58 µg/g ww); this is especially true for Pb, an element found in very high concentrations in tissues of turtles from the same area in a previous study. The sex and the size of the individuals also had significant differences in concentration of Pb, Cd, As, and Hg.

Anesthetic efficacy of ketamine-diazepam, ketamine-xylazine, and ketamine-acepromazine in Caspian Pond turtles (Mauremys caspica).

OBJECTIVES: The objective of this study was to assess the efficacy of different anesthetic drug combinations on the Caspian Pond turtles (Mauremys caspica). SUBJECTS AND METHODS: Three groups of the Caspian Pond turtles (n = 6) were anesthetized with three different drug combinations. Initially, a pilot study was conducted to determine the best drug doses for the anesthetization of the turtles, and according to these results, ketamine-diazepam (120 mg/kg ketamine hydrochloride [5%] and 2 mg/kg diazepam [5%]), ketamine-acepromazine (120 mg/kg ketamine hydrochloride [5%] and 1 mg/kg acepromazine [1%]), and ketamine-xylazine (120 mg/kg ketamine hydrochloride [5%] and 1 mg/kg xylazine [2%]) were injected intramuscularly. The onset times of anesthetization and the recovery time were measured. Statistical analysis of the data was performed using one-way analysis of variance followed by t-tests, and P < 0.05 was considered statistically significant. RESULTS: There were statistically significant differences in the mean of the onset times of anesthesia and recovery time among the three drug combinations depending on the treatment used. The onset of anesthesia of the animals treated with the ketamine-diazepam combination was 60% and 42% shorter, for male and female turtles, respectively, compared to that obtained with the ketamine-acepromazine combination and 64% (male turtles) and 50% (female turtles) shorter than that obtained with the ketamine-xylazine combination. Further, the recovery time, in male turtles, was 17% shorter in animals treated with the first drug combination than those treated with the ketamine-acepromazine combination and 37% shorter than those treated with the ketamine-xylazine combination. The recovery time, in female turtles, did not seem to be significantly different among treatments. CONCLUSIONS: The study showed that the ketamine-diazepam drug combination is the anesthetic combination with the fastest onset time and shortest recovery time.

Trace element concentrations in muscle tissue of milk shark, (Rhizoprionodon acutus) from the Persian Gulf.

We analyze the heavy metals concentrations in muscle samples of milk shark (Rhizoprionodon acutus) from Persian Gulf. The metals distribution was Zn > Cu > Pb > Cd > Hg. No statistical differences were observed among size or weight by sex (p < 0.05). Metals concentrations in the population de R. acutus from Larak and Lavan islands are homogeneous along the coastal study area. Our study suggest that the results reflect the natural contents of trace metals in this species, and the health risk associated to milk shark consumption in Persian Gulf is relatively low.

Effect of Potential Probiotic Lactococcus lactis Subsp. lactis on Growth Performance, Intestinal Microbiota, Digestive Enzyme Activities, and Disease Resistance of Litopenaeus vannamei.

The aims of this study were to evaluate the effects of Lactococcus lactis subsp. lactis on the growth, intestinal microbiota, digestive enzyme activity, and disease resistance of Litopenaeus vannamei. Diets containing four different concentrations of L. lactis (0 [basal diet], 106, 107, and 108 CFU g-1) were fed to white shrimps L. vannamei (average weight 5.89 ± 0.36 g) for 8 weeks. At the end of the feeding trial, shrimps were immersed in Caspian Seawater (10.8 ppt) contaminated with 106 CFU ml-1 pathogenic V. anguillarum for 2 h. Results revealed that growth rate, survival, and body protein level were increased with dietary supplementation of L. lactis. The activities of digestive enzymes (cellulose, lipase, amylase, and protease) were significantly higher in the groups fed with diets containing 107 or 108 CFU g-1 L. lactis than those in the control. The Lactobacillus and Bacillus counts were higher (P < 0.05) in the intestine of shrimps fed with L. lactis-supplemented diets. In addition, higher level of L. lactis supplementation decreased the Vibrio counts. Moreover, L. vannamei fed diet supplemented with 108 CFU g-1 of L. lactis exhibited significantly the highest hematocyte count and post-challenge survival rate (79.2 %). Collectively, these results suggest that dietary supplementation of L. lactis subsp. lactis at 108 CFU g-1 can promote growth performance, digestive enzyme activity, and disease resistance of L. vannamei.

Mercury, lead, and cadmium in tissues of the Caspian Pond Turtle (Mauremys caspica) from the southern basin of Caspian Sea.

Concentrations of cadmium, lead, and mercury were measured in different tissues (liver, muscle, and shell) of 60 Caspian Pond Turtles collected from Tajan and Shiroud Rivers, southern basin of the Caspian Sea. Based on the results, different tissues showed different capacities for accumulating trace elements. The general trend of metals accumulation was: liver > shell > muscle. Results also showed that accumulation of these elements was not significantly different between sex and river in turtles (p > 0.05). Based on the results, Hg and Pb concentrations recorded in the present study were higher than some of the maximum concentration permissible. To our knowledge, this is the first report into heavy metal accumulation in tissues and organs of Caspian Pond Turtle from the southern basin of Caspian Sea. Further studies are needed to measure different heavy metals and trace metals in this valuable species.

Heavy metal concentrations in edible muscle of whitecheek shark, Carcharhinus dussumieri (elasmobranchii, chondrichthyes) from the Persian Gulf: A food safety issue.

Together with several health benefits, fish meat could lead to heavy metal intoxication of consumers. In this study, we discuss Zn, Cu, Pb, Hg and Cd concentrations in fillets of forty specimens of Carcharhinus dussumieri, analyzed with atomic adsorption spectroscopy (AAS). The potential human health risks due to consumption of C. dussumieri was assessed by estimating average daily intake (EDI) and target hazard quotient (THQ) of metals. The average concentrations of metals measured in this study were (ppm dry weight): Cu 7.49 ± 0.25; Zn 3.47 ± 0.26; Pb 0.12 ± 0.03; Hg 0.028 ± 0.02; Cd 0.11 ± 0.03. Our results showed that no metal exceeded the EC and FAO limits. Cu and Cd accumulate in muscles with a body length (age)-dependent manner. The exposure daily intake of all toxic metals analyzed was found lower than the PTDI provided by WHO and the THQ resulted lower than 1, suggesting no risk for human health derived from consumption.

Effects of dietary Spirulina platensis on growth performance, humoral and mucosal immune responses and disease resistance in juvenile great sturgeon (Huso huso Linnaeus, 1754).

Dietary supplementation of Spirulina platensis at different levels (0% control, 2.5%, 5% and 10%) was evaluated to find out the effects on growth performance, digestive enzyme activities, humoral and skin innate immune responses and disease resistance in the great sturgeon (Huso huso). After 8 weeks of experimental trial, growth parameters, intestinal lactic acid bacteria count, protease and lipase activities were significantly high in 10% S. platensis fed group (P < 0.05). Similarly, in this group, respiratory burst activity of leucocytes and total protein of serum were also significantly high. Furthermore, supplementation of S. platensis at 5 or 10% exhibited higher serum IgM and lysozyme activity than the other experimental groups (P < 0.05). On the contrary, serum triglycerides and number of blood lymphocytes were lower in experimental groups than that of control group. Total proteins, lysozyme, protease and esterase, as well as in vitro bactericidal activity (against Streptococcus iniae, Yersinia ruckeri, Aeromonas hydrophila and Lactococcus garviea) were significantly high in skin mucus from fish fed 5% and 10% S. platensis, while, alkaline phosphatase was significantly high in fish fed 10% S. platensis (P < 0.05). Further, fish infected with Streptococcus iniae bacteria increased mortality, but it was alleviated by a diet supplemented with S. platensis. The present results demonstrate that this dietary supplementation with S. platensis (mainly at 10% level) could be useful for maintaining the overall health status of great sturgeon.

Hemato - Immunological and biochemical parameters, skin antibacterial activity, and survival in rainbow trout (Oncorhynchus mykiss) following the diet supplemented with Mentha piperita against Yersinia ruckeri.

This study was aimed to assess the potential effects of Mentha piperita on the hemato - immunological and biochemical parameters, skin antibacterial activity and protection against Yersinia ruckeri infection in rainbow trout Oncorhynchus mykiss. Fish were divided into 4 groups before being fed diets supplemented with 0, 1, 2 and 3% of Mentha piperita (MP) plant extract for 8 weeks. Dose-dependent increases immune (both in skin mucus and blood serum) and hematological parameters (number of red and white cells, hematocrit and hemoglobin contents), as well as in respiratory burst activity, total protein, albumin, and neutrophil levels in fish fed supplemented diets compared to the control fish. Furthermore, dietary MP plant extract supplements have no significant effect on blood biochemical parameters and enzymatic activities of liver determined in serum of rainbow trout. After 8 weeks the cessation of feeding with MP plant extract, survival rates of 54.4%, 63.6% and 75.2% were recorded in groups which received 1, 2 and 3% of MP plant extract of feed, respectively, compared to 34.6% survivals in the control. This study underlying several positive effects of dietary administration of MP plant extract to farmed fish.

A comparative study of trace metals in male and female Caspian kutum (Rutilus frisii kutum) from the southern basin of Caspian Sea.

This study focuses on the extent of zinc (Zn), copper (Cu), cadmium (Cd), cobalt (Co), manganese (Mn), lead (Pb), mercury (Hg), and arsenic (As) bioaccumulation in edible muscles of Caspian kutum (Rutilus frisii kutum), in both male and female sexes at Noor and Babolsar coastal regions from the southern basin of Caspian Sea. These values were compared with the WHO and the UNFAO safety standards regarding the amount of the abovementioned heavy metals in fish tissues (mg/kg ww). Results showed that the accumulation of these elements (except for Zn) was not significantly different between sexes of male and female in Babolsar coastal regions (P > 0.05). In the other hand, accumulation of Hg and As at edible muscles of Caspian kutum has significant difference between two sexes of male and female in Noor coastal regions (P < 0.05), the female had higher concentration than the male. Furthermore, it was not significantly correlated with sex and rivers in length and weight of fish (R 2 < 0.50; P > 0.05). Based on the results, the concentration of heavy metals in the studied fish tissues proved to be significantly lower than international standards (P < 0.05), so its consumption is not a threat to the health of consumers.

Parasitic infection in various stages life of cultured Acipenser persicus.

The present study was conducted to evaluate the status of the parasite fauna in Acipenser persicus at different development stages, in order to find prevention protocols for parasitic diseases in this valuable species. For this purpose, sampling from each sex breeder, 10 egg samples, 5-day-old larvae (n = 20), 20-day-old larvae (n = 80) and fingerling of A. persicus (n = 60) released in earthen ponds were done. After the bioassay and preparing wet mount from the internal and external organs, identification was done according to the keys. According to the results, no fauna parasites were isolated from egg samples and 5-day-old larvae; but Trichodina spp. was isolated from 20-day-old larvae. Also, the same protozoan was isolated from fingerling released in earthen ponds, the mean intensity, prevalence and range of contamination by fingerling were higher with compared to 20-day-old larvae. Trichodina sp. and Diplostomum spathaceum were isolated from skin and eyes of females, respectively. However, Trichodina sp. and Ichthyophthirius multifiliis were isolated from skin of male breeders. In this study, no parasites were isolated from internal organs of larves and fingerling but four intestinal parasites included: Cucullanus sphaerocephlaus, Anisakis sp., Skyrjabinopsilus semiarmatus, and Lepto-rhynchoides plagicephalu were isolated from internal organs of breeder. Based on a wide range of parasitic infection observed in various life stages of A. persicus, it seems necessary to consider hygienic and management measures.

Probiotics as beneficial microbes in aquaculture: an update on their multiple modes of action: a review.

Wide and discriminate use of antibiotics has resulted in serious biological and ecological concerns, especially the emergence of antibiotic resistance. Probiotics, known as beneficial microbes, are being proposed as an effective and eco-friendly alternative to antibiotics. They were first applied in aquaculture species more than three decades ago, but considerable attention had been given only in the early 2000s. Probiotics are defined as live or dead, or even a component of the microorganisms that act under different modes of action in conferring beneficial effects to the host or to its environment. Several probiotics have been characterized and applied in fish and a number of them are of host origin. Unlike some disease control alternatives being adapted and proposed in aquaculture where actions are unilateral, the immense potential of probiotics lies on their multiple mechanisms in conferring benefits to the host fish and the rearing environment. The staggering number of probiotics papers in aquaculture highlights the multitude of advantages from these microorganisms and conspicuously position them in the dynamic search for health-promoting alternatives for cultured fish. This paper provides an update on the use of probiotics in finfish aquaculture, particularly focusing on their modes of action. It explores the contemporary understanding of their spatial and nutritional competitiveness, inhibitory metabolites, environmental modification capability, immunomodulatory potential and stress-alleviating mechanism. This timely update affirms the importance of probiotics in fostering sustainable approaches in aquaculture and provides avenues in furthering its research and development.

Host-derived probiotics Enterococcus casseliflavus improves resistance against Streptococcus iniae infection in rainbow trout (Oncorhynchus mykiss) via immunomodulation.

The present study evaluated the benefits of dietary administration of host-derived candidate probiotics Enterococcus casseliflavus in juvenile rainbow trout Oncorhynchus mykiss. Experimental diets were prepared by incorporating the microorganisms in the basal feed at 3 inclusion levels (i.e. 10(7) CFU g(-1) of feed [T1], 10(8) CFU g(-1) of feed [T2], 10(9) CFU g(-1) of feed [T3]). The probiotic feeds were administered for 8 weeks, with a group fed with the basal diet serving as control. The effects on growth performance, gut health, innate immunity and disease resistance were evaluated. Results showed that growth performance parameters were significantly improved in T2 and T3 groups. Activities of digestive enzymes such as trypsin and lipase were significantly higher in these two groups as well. Gut micro-ecology was influenced by probiotic feeding as shown by the significant increase in intestinal lactic acid bacteria and total viable aerobic counts in T2 and T3. Humoral immunity was impacted by dietary probiotics as total serum protein and albumin were significantly elevated in T3. The levels of serum IgM significantly increased in all probiotic fed groups at week 8; with the T3 group registering the highest increment. Respiratory burst activity of blood leukocytes were significantly improved in T2 and T3. Hematological profiling further revealed that neutrophil counts significantly increased in all probiotic fed groups. Challenge test showed that probiotic feeding significantly improved host resistance to Streptococcus iniae infection, specifically in T2 and T3 where a considerable modulation of immune responses was observed. Taken together, this study demonstrated E. casseliflavus as a potential probiotics for rainbow trout with the capability of improving growth performance and enhancing disease resistance by immunomodulation.

Phylogenetic analysis of the glycoprotein gene of viral hemorrhagic septicemia virus from Iranian trout farms points towards a common European origin.

Viral haemorrhagic septicaemia virus (VHSV), a member of family Rhabdoviridae and genus Novirhabdoviridae, causes mortality in numerous marine and freshwater hosts located in northern hemisphere. To evaluate the genetic diversity of VHSV from the North and South West of Iran, the sequences of a 1483bp nt region of the glycoprotein gene were determined for four Iranian isolates. These sequences were analysed to evaluate their genetic relatedness with 86 worldwide isolates representing the four known genogroups of VHSV. Phylogenetic analysis by nucleotide sequences showed that all the VHSV isolates studied were closest related to the 19 fresh water strains from Germany grouped within the European genogroup Ia-2. This finding indicates that Iranian VHSV most likely was introduced to Iran by the movement of contaminated fish fry from a source in Europe.