A sensitive non-destructive method for detecting IPNV carrier Atlantic salmon, Salmo salar L., by culture of virus from plastic adherent blood leucocytes

In populations of Atlantic salmon in sea water, infectious pancreatic necrosis virus (IPNV) could be detected by standard virological culture methods in sonicated kidney homogenates and in mucus samples (gill, skin and rectum) from 14 and nine of 25 fish, respectively, but all fish were positive by virus culture from lysates of kidney macrophages and adherent blood leucocytes. In fish which tested negative for IPNV by the standard method of detection, the virus could be detected using adherent blood leucocytes isolated on a Percoll gradient from as little as 10 microL of blood. The blood sample could be stored for at least 3 days in a heparinized tube on ice before preparing the plastic adherent leucocytes. Furthermore, the latter could be prepared without prior fractionation on Percoll simply by incubating whole blood (33 microL) in cell culture medium (66 microL) in 96-well plates overnight and washing away the non-adherent cells before lysing the adherent cells and inoculation of the lysate onto CHSE-214 cells. This highly sensitive method for detecting IPNV-carriers is therefore very suitable for non-destructive sampling of fish in the field.     

Yellow head-like viruses affecting the penaeid aquaculture industry: a review

This review focuses on relevant scientific information regarding the current knowledge of the yellow head complex viruses, yellow head virus and gill‐associated virus. The yellow head complex viruses have been problematic within the aquaculture industry for over 10 years and still retain their research topicality. Presently, there are numerous research papers from different journals covering the identification, disease expression and spread, pathogenesis, detection, morphology, genomic sequence and protein profiles of the yellow head complex viruses. Indeed, there has been no extensive review to compare these studies, and as a corollary, to assess flaws in contemporary research and knowledge. Additionally, the yellow head complex viruses rank within the top four prawn viruses with respect to disease impact and economic loss. This review collectively reports on all the findings and current methods of research and aims to identify weak areas of research where conclusions have been unjustifiably drawn and furthermore to elucidate areas that have a gap of knowledge.     

Induced final maturation and ovulation in a small anabantoid teleost, the dwarf gourami, Colisa lalia. I. The effects of gonadotrophic preparations, LHRHa, steroids and thyroid hormones

Colisa lalia (Ham.) has been used as a model for the development of techniques for induced spawning that are applicable to small teleosts where ovulation requires prolonged exposure to suitable breeding conditions.Human chorionic gonadotrophin (hCG; 4 IU per fish) induced ovulation within 24 hours, whereas homologous pituitary extracts were relatively ineffective. When administered in saline ( 20 g per fish per injection), des-Gly10,[D-Ala6]- LHRH N-ethylamide (LHRHa) was ineffective, but it stimulated ovulation in a proportion of fish when administered ( 1.6 g per fish) as an emulsion in Freund's incomplete adjuvant (FIA). Together, these results suggest that ovulation requires the synthesis as well as the secretion of gonadotrophin in C. lalia.Long-term treatment with thyroid hormones appeared to enhance the ovulatory response to LHRHa in FIA, possibly by effects on the ovary; whereas the various steroids tested were ineffective at the dosages used     

Protein synthesis in rat liver: influence of amino acids in diet on microsomes and polysomes

Rats were killed 1 hour after having been fed by stomach tube with amino acid mixtures that were either nutritionally complete or lacked tryptophan. Microsomes isolated from the livers of animals fed the incomplete mixture showed a reduced capacity to incorporate (14)C-leucine in vitro, and polysomes prepared from the same livers showed an increased proportion of monosomes and disomes. Prior treatment with actinomycin D did not prevent these differences in response to the two amino acid mixtures, an indication that synthesis of messenger RNA may not be involved in the cell mechanism which recognizes differences in amino acid pattern.     

POTENTIAL PASTURE PRODUCTION IN THE UPLANDS OF WALES

Study of the growth of heavily fertilized swards of S23 perennial ryegrass (Lolium perenne) at a hill and a lowland centre in mid-Wales during 1968–69 demonstrated that lower productivity in the uplands could only be partially attributed to a shorter growing season and poorer summer growth conditions. Comparison of yields with potential transpiration estimates indicated that winter damage had an important bearing on production during the following year. In 1969, the adverse combination of a mild autumn and a severe winter led to a spring tiller density which was less than 25% of normal at the hill centre. With an annual fertilizer input of over 500 kg N/ha (480 lb N/ac) total DM production in 1968 and 1969 was 10.6 and 4.4 t/ha at the upland site compared with 14.8 and 10.1 t/ha in the lowlands (9450, 3920, 13,190 and 9000 lb/ac).     

Serum Inhibin Concentration in Dogs with Adrenal Gland Disease and in Healthy Dogs

Background

Studies in humans identified the synthesis and secretion of inhibin from adrenocortical tumors, but not pheochromocytoma (PHEO). Inhibin has not been examined in dogs as a serum biomarker for adrenal gland tumors.

Objective

To determine serum inhibin concentration in dogs with adrenal gland disease and in healthy dogs.

Animals

Forty‐eight neutered dogs with adrenal disease including pituitary‐dependent hyperadrenocorticism (PDH, 17), adrenocortical tumor (18), and PHEO (13), and 41 healthy intact or neutered dogs.

Methods

Prospective observational study. Dogs were diagnosed with PDH, adrenocortical tumor (hyperadrenocorticism or noncortisol secreting), or PHEO based on clinical signs, endocrine function tests, abdominal ultrasound examination, and histopathology. Inhibin concentration was measured by radioimmunoassay in serum before and after ACTH stimulation, and before and after treatment.

Results

In neutered dogs, median inhibin concentration was significantly higher in dogs with adrenocortical tumors (0.82 ng/mL) and PDH (0.16 ng/mL) than in dogs with PHEO and healthy dogs (both undetectable). Median inhibin concentration was significantly higher in dogs with adrenocortical tumors than in those with PDH and decreased after adrenalectomy. Median inhibin concentration was significantly higher in intact than in neutered healthy dogs and was similar in pre‐ and post‐ACTH stimulation. Sensitivity, specificity, and accuracy of serum inhibin concentration for identifying an adrenal tumor as a PHEO were 100, 88.9, and 93.6%, respectively.

Conclusions and Clinical Importance

Adrenocortical tumors and PDH but not PHEOs are associated with increased serum inhibin concentration; undetectable inhibin is highly supportive of PHEO in neutered dogs with adrenal tumors.     

A survey of wild marine fish identifies a potential origin of an outbreak of viral haemorrhagic septicaemia in wrasse,Labridae, used as cleaner fish on marine Atlantic salmon,Salmo salar L., farms

Viral haemorrhagic septicaemia virus (VHSV) was isolated from five species of wrasse (Labridae) used as biological controls for parasitic sea lice predominantly, Lepeophtheirus salmonis (Krøyer, 1837), on marine Atlantic salmon, Salmo salar L., farms in Shetland. As part of the epidemiological investigation, 1400 wild marine fish were caught and screened in pools of 10 for VHSV using virus isolation. Eleven pools (8%) were confirmed VHSV positive from: grey gurnard, Eutrigla gurnardus L.; Atlantic herring, Clupea harengus L.; Norway pout, Trisopterus esmarkii (Nilsson); plaice, Pleuronectes platessa L.; sprat, Sprattus sprattus L. and whiting, Merlangius merlangus L. The isolation of VHSV from grey gurnard is the first documented report in this species. Nucleic acid sequencing of the partial nucleocapsid (N) and glycoprotein (G) genes was carried out for viral characterization. Sequence analysis confirmed that all wild isolates were genotype III the same as the wrasse and there was a close genetic similarity between the isolates from wild fish and wrasse on the farms. Infection from these local wild marine fish is the most likely source of VHSV isolated from wrasse on the fish farms.     

A mortality event in wrasse species (Labridae) associated with the presence of viral haemorrhagic septicaemia virus

Viral haemorrhagic septicaemia (VHS) is an infectious disease of farmed and wild fish and has an extensive host range in both freshwater and marine environments. In December 2012, a wrasse population consisting of ballan, Labrus bergylta (Ascanius), corkwing, Symphodus melops (L.), cuckoo, Labrus mixtus L., goldsinny, Ctenolabrus rupestris (L.), and rock cook, Centrolabrus exoletus (L.), held at a marine hatchery in the Shetland Isles, Scotland, experienced a mortality event. Approximately 10 000 wrasse were being held at the facility on behalf of an Atlantic salmon, Salmo salar L., aquaculture company prior to being deployed for the biological control of parasites on marine pen Atlantic salmon, aquaculture sites. Fish Health Inspectors from Marine Scotland Science initiated a diagnostic investigation, and subsequent diagnostic testing confirmed the site to be VHSV positive by qRT-PCR and virus isolation followed by ELISA. A VHSV genotype-specific qRT-PCR assay revealed that the isolates belonged to genotype III, the European marine strain of the virus. The virus genotype was further confirmed by nucleic acid sequencing of the partial nucleoprotein (N) and glycoprotein (G) genes followed by BLAST nucleotide searches. This study reports for the first time the detection of VHSV within multiple wrasse species and highlights the need for a comprehensive risk-based approach to the use of wrasse and other finfish species as biological controls within the aquaculture industry.