A rapid immunoperoxidase-based virus neutralization assay for salmonid alphavirus used for a serological survey in Northern Ireland

A modified virus neutralization (VN) assay was developed to replace an existing assay read on the presence or absence of virus-induced cytopathic effect (CPE). The modified assay used a monoclonal antibody to salmon pancreas disease virus as the first layer of an immunoperoxidase (IPX)-based immunostaining technique to detect viral growth. The IPX-based VN assay required only 3 days to perform, and the adoption of a 96-well microtitre format facilitated a high throughput of samples requiring small volumes of serum, cells and virus. When 352 sera from farmed salmon and 302 sera from farmed trout were tested by both the modified and the original CPE-based assays, overall correlations of 97.72 and 96.03% were, respectively, obtained (96.94% combined). When the modified assay was used to test 188 sera collected from wild salmonids in freshwater river systems in Northern Ireland, no positive results were recorded.     

Use of collagen shields for treatment of chronic bilateral corneal ulcers in a pet rabbit

A four-year-old, 1·3-kg entire male Holland Lop pet rabbit (Oryctolagus cuniculus) was presented with a two-day history of bilateral epiphora and blepharospasm. Fluorescein staining revealed bilateral medio-ventral corneal ulceration. Initial topical treatment included ophthalmic broad-spectrum antibiotics and artificial tear solutions. Over a six-month period, antibiotics were changed based on corneal culture and sensitivity test results, and periodic corneal debridement was performed. With little to no improvement, and recurrence of the previous clinical signs, surgical intervention was considered but withheld because of individual pet consideration and owner's reluctance. Hydrophilic contact lenses were placed for corneal support but failed and caused a severe ocular response. Corneal collagen shields were placed bilaterally in order to promote corneal healing. Recheck examination performed seven days after placement revealed complete resolution of the ulcer in one eye and major reduction of the corneal ulcer in the contra-lateral eye.     

IHHN virus: Infectivity and pathogenicity studies in Penaeus stylirostris and Penaeus vannamei

Infectivity studies of infectious hypodermal and hematopoietic necrosis virus (IHHNV) were conducted on Penaeus stylirostris and P. vannamei (representing species highly susceptible and highly refractory to the disease) via intramuscular injections of the virus. Distinctive histological lesion patterns were observed between species. Six target organ systems were compared interspecifically. The gills and nerve cord/ganglia were shown to undergo significantly higher degrees of tissue damage in infected P. stylirostris compared with infected P. vannamei. Pathogenetic differences correlated well with observed differences in epizootiology between the two species.The infectivity study confirmed that IHHN disease is virus-caused. Cell-free extracts from IHHNV-infected shrimp, when injected into healthy, susceptible shrimp, produced mortalities and Cowdry type A intranuclear eosinophilic inclusion bodies presently considered pathognomonic for the disease.     

Evaluation of interferon gamma (IFN-γ) of <Emphasis Type="Italic">Labeo rohita</Emphasis> as an immunomodulator: in vitro expression model

Interferon gamma (IFN-γ) or type II interferon is a cytokine that is critical for innate and adaptive immunity against viral and some bacterial and protozoal infections. The importance of IFN-γ in the immune system lies in its ability to inhibit viral replication directly and most importantly from its immunomodulatory effects. Previously, we successfully co-administered IFN-γ along with GAPDH gene of Edwardsiella tarda as bicistronic DNA vaccine in Labeo rohita. In order to ascertain the individual role of IFN-γ, the present study involves cloning and expression of 552-bp IFN-γ open-reading frame (ORF) of L. rohita in striped snakehead (SSN-1) cell line using eukaryotic expression vector system (pQE-TriSystem) followed by transfection in peripheral blood lymphocytes (PBMCs) to evaluate its immunomodulatory ability in comparison to polyinosinic-polycytidylic acid (Poly I:C)-treated PBMCs. The 18.7-kDa protein, expressed in the pQE-IFNγ-transfected SSN-1 cells, reacted with anti-His antibody in Western blot confirming it to be recombinant IFN-γ, whereas the relative expression of IFN-γ, iNOS, Mx, and IL-1β genes in PBMCs was quantified at 24 h and 48 h post treatment by qPCR. The comparative kinetics of all four genes showed significantly (p?<?0.05) high upregulation pattern in both pQE-IFNγ-transfected cell group and Poly I:C-treated cell group demonstrating recombinant IFN-γ as an equally efficient inducer like Poly I:C. Thus, our in vitro experiment results highlight the immunomodulatory potential of recombinant IFN-γ as an analogue to synthetic Poly I:C which warranted future studies to further explore the potential of recombinant IFN-γ as an effective vaccine adjuvant against different microbial invasion.     

Growth, digestive enzyme activities and hepatic glycogen levels in juvenile Colossoma macropomum Cuvier from South America during feeding, starvation and refeeding

Abstract. Feeding trials with juvenile Colossoma macropomum Cuvier (approximately 40g) were carried out to study their protein requirements and their efficiency in metabolizing vegetable protein. Two groups of diets were used. In one group, the crude protein consisted exclusively of fish protein concentrate. In the second group the protein consisted of a mixture (55:45) of vegetable and animal protein without fish meal. In each group 30 and 50% protein levels were used. The highest weight increase (1·64%/day) and the lowest feeding rate were obtained with the 50% protein fish meal free diet. During the trial all fish accumulated visceral fat while body protein content decreased and dry matter increased. There was a high correlation between liver weight and liver glycogen. The highest amounts of liver glycogen were induced by diets containing fish meal and/or low protein content. In contrast lo visceral fat deposits, accumulated liver glycogen was of less significance for surviving starvation periods. The activity of digestive enzymes depends on both stomach and gut fullness. Trypsin activity, contrary to pepsin, was correlated with diet protein content, a-amylase activity was not correlated with diet composition.     

Mating and spawning of freshwater crayfish, Austropotamobius pallipes Lereboullet, under laboratory conditions

Abstract. The study includes mating and spawning data of freshwater crayfish, Austropotamobius pallipes Lereboullet, obtained in four consecutive years (1987–1990). A total number of 586 wild-caught female A. pallipes in the 21·65 mm to 45·60mm carapace length (CL) size were held under laboratory conditions at different dates in September–October. Initial densities at mating time were 21 and 24 crayfish/m² with a 1:2 male:female ratio. High percentages of mating were obtained (97·4–100%) except in 1989 (57·5%). In all years, most of the matings (90%) were concentrated in a period of 8–12 days with mean water temperatures between 12°C and 13·5°C. Spawning took place a few days after mating (minimum 2 days, maximum 14 days) at mean water temperatures between 8·2°C and 10·8°C. In the first 3 years, almost 100% of mated females spawned. However, in the fourth year (1990), when the mean size of crayfish was smaller, only 72·4% of mated females spawned. The mean number of pleopodal eggs was 64 (maximum 220, minimum 18). Egg diameter ranged between 2·30 and 3·25 mm (mean value 2·78 mm). Pleopodal egg number was positively correlated with carapace length ( r = 0·72).     

Assessing the opportunities for upstream migration of non-salmonid fishes in the weir-regulated River Vecht

The degree of obstruction posed by weirs to potential upstream movements of non-salmonid fish (predominantly cyprinids) in the River Vecht, the Netherlands, was assessed. This rain-fed river showed high variability in discharge, providing opportunities for passage at high discharge when weirs were free flowing. Daily recorded discharge and water levels between 1960 and 1984, and an analysis of swimming capacities and migratory behaviour, were used to assess whether hydraulic conditions each day and for each species were suitable for ascent. The assessment demonstrated that migratory opportunities along the six weirs were extremely limited. Only 10 of 32 species were able to ascend all weirs in 5–30% of the years. Opportunities were the greatest for large-sized species during November–March at the downstream-situated weirs, whereas small-sized species had no opportunities year-round. The approach used is widely applicable for barrier assessment in other rivers, because it requires only basic hydraulic measurements that are often available.     

Oyster greening by outdoor mass culture of the diatom Haslea ostrearia Simonsen in enriched seawater

Oyster greening was first described in the seventeenth century as a natural phenomenon. However, it has recently been discovered that the diatom Haslea ostrearia Simonsen causes greening by synthesis of a blue pigment designated as ‘marennine’. This phenomenon, which involves massive proliferation of H. ostrearia in oyster ponds, was not understood or controlled by oyster farmers in the Marennes‐Oléron region (Atlantic coast of France). As greening oysters improved their market value, they tried to develop empirical methods to guarantee oyster fattening and improve profits. In this context, the present study investigated the feasibility of mass culture of diatoms outdoors in 10‐m³ ponds, using enriched seawater. Different biotic and abiotic parameters were monitored daily to determine the influence of the day–night temperature range. After 8 days, H. ostrearia was the dominant diatom species (66%), reaching a mean cell concentration of 2 × 10⁵ cell mL^?1 and a marennine concentration of 3.4 mg L^?1. Although intensive greening was obtained, further studies are required to optimize the production stages before this technology can be transferred to oyster farmers.     

Biochemical,Physical, Chemical,and Microbiological Assessment of Blue Shrimp (Litopenaeus stylirostris) Stored in Ice

Postmortem changes in blue shrimp (Litopenaeus stylirostris) muscle were studied on the basis of biochemical, chemical, physical, and microbiological changes during an 18 day storage period at 0°C. Adenosine 5′-triphosphate (ATP) content, breakdown products, K-value, pH, trimethylamine nitrogen (TMA-N), total volatile basic nitrogen (TVB-N), water holding capacity (WHC), color, and texture (shear force) changes were examined. Also, total mesophilic and psychrophilic bacterial counts were measured. K-value increased linearly (r² = 0.98) from an initial value of 1.37 ± 0.59 to 59.42 ± 6.05% at Day 18. Spoilage indicators TVB-N and TMA-N increased from 29.56 ± 1.33 and 0.69 ± 0.25 to 39.04 and 2.04 ± 0.59 mg of N/100 g at Day 18, respectively; meanwhile, the total viable counts of mesophilic and psychrophilic bacteria increased from 3.48 ± 0.44 and 2.61 ± 0.29 log CFU/g to 6.27 ± 0.21 and 7.14 ± 0.39 log CFU/g, respectively, which indicated spoilage at the end of the storage period. The pH, texture, WHC, and color were affected (p < 0.05) during the storage period. Overall, results indicate that blue shrimp muscle quality was maintained for 12 days of storage in ice.     

An alarming tendency towards freshwater mussel misidentification in scientific works may bias endangered and invasive species management

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