Gross clinical signs and haematological changes associated with artifical infection of Edwardsiella tarda in Koi Carp

The occurrence of diseases is a significant setback for successful aquafarming. One of the common fish bacterial disease syndromes, Edwardsiellosis is caused by Edwardsiella tarda, a gram-negative, rod shaped bacterium associated with several diseases of marine and fresh water fish. In this study, an attempt was made to observe and analyze the onset of clinical symptoms and certain haematological parameters in Koi Carp, Cyprinus carpio L., following artificial infection with Edwardsiella tarda. The disease progress was observed and the clinical symptoms were monitored over a period of 15 days following infection. Fish were sampled at three day intervals to analyse the haematological parameters: total erythrocyte counts (RBC), total leucocyte counts (WBC), haemoglobin content and differential leucocyte count. Clinical symptoms observed included: erratic swimming behaviour, loss of appetite, haemorrhages, dropsy and exophthalmia. There was a significant decrease in the total RBC and haemoglobin levels by the 3rd and 6th day post infection, and an increase thereafter. WBC counts were higher in all infected groups in comparison to the control group. A significant increase in the number of neutrophils was found in the infected group up to the 9th day and a decrease thereafter. The lymphocyte number was significantly less up to the 12th day while the monocyte counts were significantly higher up to the 12th day post infection. The results showed that the bacterium, E. tarda, is pathogenic to Koi Carp. The hematological changes and clinical signs in infected fish reported in this paper will be helpful in the identification and the control of this infection.

Effect of dietary inulin as prebiotic on growth, survival and intestinal bacterial density of juvenile great sturgeon (Huso huso)

Use of prebiotics, nondigestible dietary ingredients that beneficially affect the host by selectively stimulating the growth of and/or activating the metabolism of healthpromoting bacteria in the intestinal tract, is a novel concept in aquaculture. An 8-week feeding experiment was conducted to investigate the effects of dietary prebiotic inulin on the growth performance, intestinal bacterial density, body composition and values of blood serum enzymes in the juvenile great sturgeon (Huso huso). Three replicate groups of fish (initially averaging weight 16.14±0.38g) were fed diets containing prebiotic inulin at levels ranging from 1% to 3%. The basal diet was contained 3% cellulose. The results of linear regression showed there was a negative relationship between some performance indices including weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), net protein utilization (NPU), energy retention (ERE), feed efficincy (FE), protein retention (PR) and supplementation level of inulin. At the end of trial, the 1% inulin treatment insignificantly showed an enhaced survival between the treatment groups. Intestinal lactic acid bacteria (LAB) increased in group treated with 1% inulin compare to other groups. No significant difference were observed in body composition and level of serum enzymes (P>0.05). Moreover there was significant correlation between ALT and LDH values (P<0.01). Result obtained in this study shows that the prebiotic inulin didn’t influence the increase of the growth performance of juvenile great sturgeon and it is not appropriate for supplementation in the diet of beluga.

Water budgeting studies on the hatchery and nursery rearing practices for the common carp, Cyprinus carpio (Linnaeus, 1758)

Aquaculture systems are an integral element of rural development and therefore should be environment friendly as well as socially and economically designed. From the economic standpoint, one of the major constraints for the development of sustainable aquaculture includes externalities generated by competition in access to a limited resource. This study was conducted as an investigation into the water requirement for the hatchery and nursery production phases of common carp, Cyprinus carpio (Linnaeus, 1758) at the Maharashtra State Fish Seed Farm at Khopoli in Raigad Dist. of Maharashtra during the winter months from November to February. The water budgeting study involves the quantification of water used in every stage of production in hatchery and nursery systems and aimed at becoming a foundation for the minimization of water during production without affecting the yield; thereby conserving water and upholding the theme of sustainable aquaculture. The total water used in a single operation cycle was estimated to be 11,25,040 L [sic]. Out of the total water consumed, 4.74% water was used in the pre-operational management steps, 4.48% was consumed during breeding, 62.72% was consumed in the hatching phase, 21.50% was used for hatchery rearing and 6.56% was consumed during conditioning. In the nursery ponds, the water gain was primarily the regulated inflow coming through the irrigation channel. The total quantum of water used in the nursery rearing was 31,60,800 L [sic]. The initial filling and regulated inflow formed 42.60% and 57.40% respectively of water gain, while evaporation, seepage and discharge contributed 20.71%, 36.46% and 42.82% respectively to the water loss. The total water expended for the entire operation was 1,21,61,120 L [sic]. Water expense occurred to produce a single spawn in the hatchery system was calculated and found to be 0.56 L while the water expended to produce one fry was calculated as 4.86 L. The study fulfills the hydrological equation described by Winter (1981) and Boyd (1985). It also validates the water budget simulation model that can be used for forecasting water requirements for aquaculture ponds (Nath and Bolte, 1998).

Study ectoparasite infestation of 10 common imported freshwater ornamental fish species

In the present study, ectoparasite infestation of common freshwater ornamental fish species imported into Iran including: Dwarf gourami (Colisa lalia), Angelfish (Pterophyllum scalare), Oscar (Astronatus ocellatus), Red eye Tetra ( Moenkhansia Sanctaefilomenae), Barb( Capoeta tetrazona), Arowana (Osteoglossum bicirrhosum), Goldfish(Carassius auratus), Red fin Shark (Lebeo elythrurus, Catfish (Hypostomus plecostomus) and Pangasius sutchi ( Pangasius hypophthalmus) from May until April was investigated.A total of 6 specimens sample of each fish species) randomly were obtained and taken alive to the lab. After observing gill and skin wet smear under the microscope , gill was dissected and examined carefully .Photo and films were taken from the isolated parasites and parasite identification was performed according to Yamaguti AP1), Bychowsky (■Y).From a total of examined fishes 1\ ► sample (YY.V.) were parasitized .Parasite groups that were observed consisting ciliated protozoan myxosporidian , monogenean Digenean metacercaria and crustacean .The only non-parasitized fish was Barb. Monogenea Trianchoratus sp. , Cleidodiscus sp. , Ancylodiscoides sp. , Thaparocleidus sp. , Centrocestus formosanus metacercaria and Myxobolus longisporus report for the first time in ornamental fish which imported from Southeast of Asia to Iran. According to the results, it seems that severe quarantine and sanitary rules are necessary.

Fish species diversity, and the biology and ecology of common fish species in Lake Albert

Lake Albert contributes about 10% to the national fish production. It supports a multi-species fishery based on endemic species. To local fishermen, Lake Albert is a lifeline providing food and income.

Brazil: for the common good

Faced with the difficult context of conflicts and over-bureaucratization, traditional fishing communities in Brazil have creatively built various strategies of confrontation and resistance.

Chemical, microbiological and sensory examinations of dried Lake Tanganyika sardine presently marketed in Zambia

Proximate composition, PH, total aerabic counts, coliform counts, appearance and taste of dried Lake Tanganyika sardine (Limnothrissa miodon and Stolothrissa tanganicae) sampled at Lusaka markets were analysed for the period July 1969 to February 1970. Water content for the dried sardine varied between 7 and l4% and oil content between 8 and 14% according to season. Flavour of the cooked sardine was scored as good to fair, which discredits the common belief that is poor in quality. Cooked fish scores correlated poorly to the oil content and bacterial counts of the dried fish.

The bacterial cytoskeleton modulates motility, type 3 secretion, and colonization in Salmonella.

Although there have been great advances in our understanding of the bacterial cytoskeleton, major gaps remain in our knowledge of its importance to virulence. In this study we have explored the contribution of the bacterial cytoskeleton to the ability of Salmonella to express and assemble virulence factors and cause disease. The bacterial actin-like protein MreB polymerises into helical filaments and interacts with other cytoskeletal elements including MreC to control cell-shape. As mreB appears to be an essential gene, we have constructed a viable ΔmreC depletion mutant in Salmonella. Using a broad range of independent biochemical, fluorescence and phenotypic screens we provide evidence that the Salmonella pathogenicity island-1 type three secretion system (SPI1-T3SS) and flagella systems are down-regulated in the absence of MreC. In contrast the SPI-2 T3SS appears to remain functional. The phenotypes have been further validated using a chemical genetic approach to disrupt the functionality of MreB. Although the fitness of ΔmreC is reduced in vivo, we observed that this defect does not completely abrogate the ability of Salmonella to cause disease systemically. By forcing on expression of flagella and SPI-1 T3SS in trans with the master regulators FlhDC and HilA, it is clear that the cytoskeleton is dispensable for the assembly of these structures but essential for their expression. As two-component systems are involved in sensing and adapting to environmental and cell surface signals, we have constructed and screened a panel of such mutants and identified the sensor kinase RcsC as a key phenotypic regulator in ΔmreC. Further genetic analysis revealed the importance of the Rcs two-component system in modulating the expression of these virulence factors. Collectively, these results suggest that expression of virulence genes might be directly coordinated with cytoskeletal integrity, and this regulation is mediated by the two-component system sensor kinase RcsC.