Protease Inhibitory Activity in Selectively Bred Families of Eastern Oysters

Abstract

In an effort to identify potential biochemical markers for resistance to Dermo, a disease that afflicts eastern oysters Crassostrea virginica, selected stocks of these oysters were interbred to produce 10 families with high interfamily and intrafamily genetic variability; subsamples of 2-year-old oysters from each family were then assessed for protease inhibitory (PI) activity against proteases of Perkinsus marinus, the causative agent of Dermo. The prevalence and intensity of the pathogen were determined via Ray's fluid thioglycollate medium test. Family survival under field challenge, disease intensity, and PI activity were compared to evaluate family performance. In the laboratory, three families had the highest survival rates, lowest average numbers of parasite cells, and highest average PI activity. In field challenges, the same three families exhibited the lowest cumulative mortality. Among all families, disease intensity was negatively correlated with PI activity; mortality patterns also indicated an inverse relationship between disease intensity and such activity.     

Detection of Minchinia occulta in samples of pearl oysters Pinctada maxima infected by Haplosporidium hinei

Objective   To determine if juvenile pearl oysters ( Pinctada maxima ) infected with Haplosporidium hinei are also infected with another haplosporidian parasite, Minchinia occulta .
Design   Archived samples of pearl oysters infected with H. hinei were examined using polymerase chain reaction (PCR) assays and in situ hybridisation (ISH) to analyse and identify haplosporidians. A 144-bp and 220-bp region of Minchinia DNA were targeted by PCR and amplified DNA from formalin-fixed H. hinei -infected pearl oyster samples was sequenced. A 25-bp oligonucleotide probe targeting a variable section of the parasite's small subunit rRNA gene was used in ISH.
Results   The results of DNA-based diagnostic assays supported each other. The sequences obtained by PCR were found to be almost identical to M. occulta from rock oysters and the ISH assay demonstrated infection with M. occulta in affected pearl oysters. ISH indicated a prevalence of infection of 26.7% in one of the previous outbreaks.
Conclusion   Pearl oyster spat are susceptible to infection by a Minchinia parasite, most likely M. occulta , which was recently identified in rock oysters within the pearl-producing zones of Western Australia and is associated with mortalities of up to 80% in this species. The occurrence of haplosporidian co-infections in pearl oysters suggests the immunocompetence of juvenile oysters may be an important factor in preventing infection and therefore preventing mortalities such as those occurring in the recent outbreaks of pearl oyster oedema disease.     

Lythrum hyssopifolia (lesser loosestrife) poisoning of sheep in Victoria

Objective To document an ovine disease attributed to the consumption of Lythrum hyssopifolia (lesser loosestrife). Procedures Historical and histological review of field and experimental cases. Results 1–20% mortality occurred in sheep flocks grazing paddocks where L. hyssopifolia was the predominant green vegetation. Well‐documented disease outbreaks occurred in summer on nine farms across Victoria between 1974 and 2002. Liver damage occurred in all nine outbreaks, with kidney damage in at least eight. Hepatocyte necrosis was usually zonal to midzonal (zone 2) in the liver samples from four farms and periacinar (zone 3) in those from three farms, but some livers showed only single‐cell necrosis. Multinucleate hepatocytes near necrotic areas were a feature in six cases. Proximal tubular epithelium appeared to be the primary renal target and brown granules were often present in renal tubules. Biochemical and histological evidence of liver and kidney damage was obtained from two sheep experimentally pen‐fed harvested L. hyssopifolia. Conclusion Chemicals in L. hyssopifolia are toxic to ovine hepatocytes and renal tubular epithelial cells.     

Summer Mortalities and Incidental Parasitisms of Cultured Pacific Oysters in Alaska

Abstract

During the summer of 1987, surface seawater temperatures in Alaska were unseasonably warm, periodically approaching 20°C with salinities of 29‰ in late July and early August. During this period at least one Alaskan oyster grow-out station sustained excessive mortalitygreater than 50%-within a group of 150,000 18-month-old Pacific oysters Crassostrea gigas. These oysters continued to die despite later reported declines in both seawater temperature and salinity. Histological examination of moribund oysters indicated mature or nearly mature gametes in both sexes and infiltration of tissues by opportunistic secondary invaders composed primarily of various bacterial types and the flagellate protozoan Hexamita sp. An incidental, but potentially pathogenic, rickettsia-like organism that formed cytoplasmic inclusions within vesicular connective tissues was also observed in some of the oysters. Circumstances associated with this oyster mortality were similar to those accompanying summer mortalities of raft-cultured Pacific oysters in Japan, where deaths were caused by physiological stress from rapid gonadal development or a prolonged prespawning condition.     

Peritonitis and Pericarditis Associated with Gastric Perforation by a Retained Fishing Hook in a Blue Shark

Abstract

A blue shark Prionace glauca caught in 1998 by a recreational fisherman off Long Island, New York, had a peritoneal mass involving the gastric wall and extending to the transverse pericardium. The surfaces of this mass and the adjacent gastric serosa were finely granular and dull, as were the parietal and visceral pericardia. The pericardial fluid was turbid, granular, and reddish. Sectioning the fibrous mass revealed that it had numerous foci of liquefaction necrosis and that it contained a corroded fishing hook perforating the gastric wall. Bacterial cultures from the coelomic and pericardial fluids yielded Pseudomonas putrefaciens and Corynebacterium sp. Samples from the gastric mass, transverse pericardium, and heart were examined microscopically. Histopathological findings included transmural fibrosing and necrotizing gastritis, proliferative peritonitis, and pericarditis. Intralesional bacteria and algae were found within the gastric wall and adherent to the peritoneum, pericardium, and endocardium. The low body weight of this shark was compatible with cachexia. This is the first report of a systemic debilitating disease associated with a retained fishing hook in a shark. The role of retained fishing hooks in the morbidity and mortality of large pelagic shark species needs to be examined in further studies.     

Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers

Twenty 10‐month‐old Japanese Black steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers (Clay group) were fed the clay (50 g/day) during 10–30 months of age. The other 10 steers (Control group) were not fed it. There was no significant difference in body weight or average daily gain between the two groups (P > 0.05). The occurrence of fat necrotic mass in the Clay group (30%) was lower (P < 0.05) than that in the Control group (90%) at slaughter. The size of necrotic masses in the Clay group was smaller (P < 0.05) than that in the Control group. There was no significant difference in the marbling score, beef color, Longissimus muscle area or subcutaneous fat thickness between the two groups. These results suggest that the clay prevented the occurrence of fat necrosis and did not affect the carcass characteristics in Japanese Black steers.     

A Viral Disease in Larvae and Juveniles of the Japanese Flounder Paralichthys olivaceus

Abstract

From 1985 to 1987, outbreaks of a disease resulting in mass mortality occurred in larvae and juveniles of the Japanese flounder Paralichthys olivaceus cultured at prefectural and private hatcheries in Hiroshima Prefecture, Japan. The disease occurred in 10-30-d-old fish that were reared at about 18–20°C, and mortality usually reached 80–90% in a few weeks. The affected fish had opaque fins and a hyperplastic epidermis on the fins and skin. Electron microscopy revealed hexagonal virus particles in the nucleus (100–140 nm in diameter without an envelope) and cytoplasm (190–230 nm with an envelope) of the affected epidermal cells. Although isolation of the causative agent by the use of five fish-cell cultures was not successful, the disease was transmitted to healthy larval flounder by exposing them to a 0.45-μm filtrate of diseased fish homogenate. The agent's morphological features and its sensitivity to ether, to a pH of 3, and to a 30min exposure to 50°C indicate it is a herpesvirus.     

Production traits of litters in 2 crossbred Duroc pig lines

Genetics of different pig lines affects litter size, birth weight, and neonatal losses. Low birth weight has long been associated with neonatal losses, but piglet body mass index is reported to show stronger correlation with stillbirth. The aim of this study was to investigate differences in litter size, number of stillborn piglets, piglet BW gain, and body mass index between 2 different Duroc crossbred lines. Landrace × Yorkshire sows in 2 farms (n = 89) were divided into 2 groups on each farm. One group of sows on each farm was inseminated with semen from Landrace × Duroc boars (boar group LD, n = 48), and the other was inseminated with semen from purebred Duroc boars (boar group DD, n = 41). Piglets were monitored from birth to weaning at the age of 5 wk. Litter size in boar group LD was larger than in boar group DD (P = 0.03). Number of stillborn piglets in boar group LD tended to be greater than in boar group DD (P = 0.07). Piglets in boar group DD had a greater BW at birth (P = 0.02) and at 3 wk (P = 0.01) than those in boar group LD. Body mass index from birth to weaning was greater in piglets in boar group DD vs. LD (P < 0.01), and both BW and body mass index of liveborn piglets at birth for both groups combined showed a positive correlation with survival at weaning (P < 0.01). In conclusion, breeding for larger litter size in boar group DD may be one approach to increase the number of vigorous piglets in production, but the inverse relationship between litter size and birth weight was more pronounced for this group than for boar group LD (P = 0.03). Further studies of the impact of litter size on BW gain are necessary before a final conclusion can be reached.     

Tongue atrophy as a neurological finding in hereditary polyneuropathy in Alaskan malamutes

BackgroundTongue atrophy with wrinkling as a clinical sign of inherited polyneuropathies has not been reported in dogs.ObjectivesClinically describe tongue atrophy as well as morphology of the tongue and hypoglossal nerve in Alaskan malamute polyneuropathy (AMPN).AnimalsSix client‐owned Alaskan malamute dogs diagnosed with AMPN, all homozygous for the causative mutation in the N‐myc downstream‐regulated gene 1 (NDRG1) and 1 neurologically normal control Alaskan malamute.MethodsProspective case study. Clinical and neurological examinations were performed on affected dogs. Necropsy samples from the tongue muscle and hypoglossal nerve were examined by light and electron microscopy.ResultsAll affected dogs had abnormal wrinkles and grooves on the dorsal surface of the tongue, a clinical sign not described previously in dogs with AMPN. Electromyography of the tongue performed in 2 dogs showed spontaneous activity. Five affected dogs underwent necropsy studies. Histopathology of the tongue showed groups of angular atrophic myofibers and changes in the hypoglossal nerve included thinly myelinated fibers, small onion bulbs, folded myelin, and axonal degeneration.Conclusion and Clinical ImportanceHistopathologic changes in the tongue and hypoglossal nerve were consistent with previously reported changes in skeletal muscle and other nerves from dogs with AMPN. Therefore, we conclude that macroscopic tongue atrophy is part of the disease phenotype of AMPN and should be considered a potential clinical sign in dogs with polyneuropathies.     

Vitamin A Deficiency in Cherry Salmon

Abstract

Cherry salmon Oncorhynchus masou (also called amago salmon) were fed a diet with no vitamin A, and control fish were fed the same purified diet but with 5,000 IU retinyl acetate/ 100 g of diet. After 15 weeks of feeding, the fish deprived of vitamin A displayed nutritional deficiency signs, including reduced growth, pale body color, red fins, and truncated snout. The group of vitamin A-deficient fish had 5.6% mortality by the end of 22 weeks, whereas the control group had none. Hematological examination revealed severe anemia. Histological examination revealed separation of hepatic laminae and formation of thin collagen fibers between the separated laminae, atrophic and necrotic lesions in the hepatic parenchyma, numerical atrophy in the hematopoietic tissue and compensatory production of fibroadipose tissue, poorly formed bony tissue in the skull and vertebral protuberance, degeneration of skeletal and cardiac muscle fibers, numerical atrophy of pancreatic acinar cells, and thinning of the epidermis accompanied by a decrease in the numbers of mucous cells. These changes were reversed to some degree after 4 weeks on a complete diet. No pathological changes were apparent in the stomach, intestine, pyloric ceca, gills, brain, pituitary, or eyes.     

Prevalence of Infectious Pancreatic Necrosis Virus on Salmonid Fish Farms in Spain

Abstract

In Spain, salmonid fish farming was commercially developed in the 1960s, and now there are 140 private farms that depend heavily on imported embryonate eggs. Infectious pancreatic necrosis was first clinically diagnosed in Spain in 1970, but the virus (IPNV) was not isolated and identified until 1980. Since that time, researchers have isolated IPNV from other samples in Spain. A diagnostic survey was conducted to determine how prevalent IPNV is on fish farms in Spain and whether the virus has been responsible for some of the major financial losses occurring every year on these farms. In total, 236 samplings of rainbow trout Oncorhynchus mykiss from 31 farms in eight hydrographic areas were done over a 3-year period. Infectious pancreatic necrosis virus was isolated in 94 cases, and serotyping of the viral strains revealed that 81% of these isolates were strain Sp and 19% were strain Ab. Neither IPNV strain VR-299 nor rhabdovirus (as infectious hematopoietic necrosis virus or viral hemorrhagic septicemia virus) was detected in any of the samples.     

Streptococcus suis type 2 infections in pigs in the Netherlands (part two)

Summary

Since 1983 some pig breeding and fattening farms in the Netherlands have been faced with a considerable mortality in pigs due to Streptococcus suis type 2 infections. The most predominant clinical feature of S. suis type 2 infection is meningitis, although sudden deaths often occur. It was noted that some affected farms had imported breeding stock from the United Kingdom.

Tonsils of slaughter pigs were collected from herds with and without a history of S. suis type 2 infections. Bacteriological examination was done by using an elective‐selective medium. No significant difference was found in carrier rates of S. suis type 2 between clinically healthy and affected herds (38% vs. 45%).

A cohort study was carried out by regular bacteriological examination of tonsil biopsies on a farm with a high incidence of streptococcal meningitis. Twenty‐seven percent of the pigs were carriers of S. suis type 2 at nine weeks of age. Possible methods for disease control are discussed.     

Incidence,economic effects,and control of Haemophilus pleuropneumoniae infections in pigs

Summary

This thesis synopsis reports the results of investigations on:

– the incidence of clinical and subclinical H. pleuropneumoniae infections on pig farms in North Brabant;

– the economic loss on fattening farms; the effect of husbandry;

– the possibility of eradicating H. pleuropneumoniae on infected breeding farms on the basis of serological testing;

– the possibility of control on fattening farms by means of vaccination.

The principal findings were as follows:

Clinical and subclinical H. pleuropneumoniae infections are widespread on pig farms in North Brabant:

The greatest economic loss was due to mortality and veterinary fees; the daily weight again was not found to be affected.

The effect of husbandry.

Less mortality occurred: on farms where the animals were not shifted during the fattening period; in compartments where the all‐in all‐out method was systematically used; in compartments with thermostatically controlled warming of the incoming air; in compartments meeting all standards of a good housing climate.

Various sanitation measures on infected breeding farms were not successful.

Only one experimental vaccine afforded good protection, but because of a high percentage of injection abscesses this vaccine was unsuitable for use in practice.     

White Spot Syndrome Virus Infection of Cultured Shrimp in China

Abstract

In 1993 and 1994, an epizootic of disease (white spot) occurred among cultured shrimp in China, resulting in mass mortality. During the periods of outbreak epizootiological surveys were undertaken. Based on these surveys it is known that the disease occurred among populations of cultured Penaeus chinensis, P. japonicus, and P. monodon, infecting shrimp from 2.4 cm to adult. The disease presumably spread among farms as a result of transport of contaminated shrimp seedlings and seawater. Water temperatures exceeding 25°C caused the disease to spread more rapidly. Challenge experiments showed the causative agent was highly virulent. Both naturally and experimentally infected shrimp exhibited white spots on the carapace. Moribund shrimp contained turbid hemolymph, hypertrophied lymphoid organ, and a necrotic hepatopancreas. By electron microscopy, viral particles were observed in gills, stomach, lymphoid organ, and hypodermal tissue of infected shrimp. The virions were slightly ovoid with an envelope and averaged 350 × 150 nm and nucleocapsids measured 325 × 120 nm in size. By use of negative stains, complete virions were 375 × 157 nm and unenveloped nucleocapsids averaged 395 × 83 nm.     

An overview of dropped hock syndrome cases in New Zealand cattle

ABSTRACT

Case history: Data were collected from 47 outbreaks of dropped hock syndrome (DHS) that were reported by veterinarians in New Zealand to the Ministry for Primary Industries between October 2012 and August 2017. There were 181 affected dairy cows from 44 farms. Of those with records, all 86 were aged between 2–3 years-old, and 4/94 (4%) were Friesian, 56/94 (60%) were Jersey and 33/94 (35%) were Jersey/Friesian cross. Of the 47 outbreaks, 45 (96%) occurred during winter and 37 (79%) in the South Island.

Clinical findings: Of 151 cases with records, hindlimb weakness (117 cows), shortened gait (112 cows) and dropped hocks (106 cows) were most commonly reported, with 110 cases being bilaterally affected. The level of diagnostic work-up and the data recorded by veterinarians for each outbreak were highly variable. Creatine kinase and aspartate aminotransferase activities were reported for 22 cases and were within normal ranges for cows with mild disease but increased in cows with severe disease. Concentrations of Cu in serum and liver were below normal for 13/22 and 9/10 cows, respectively, from six outbreaks. Of 41 cows with records for clinical outcomes, 12 had complete resolution, 18 had partial resolution, and 11 had no resolution.

Pathological findings: Post-mortem data were available from 26 cases. Muscle necrosis and haemorrhage of the origin of the gastrocnemius muscle were the key gross findings. In 14 cows with records for muscle histopathology, myodegeneration and recent haemorrhage were observed, and connective tissue pathology was reported to predate muscular pathology in seven cases.

Diagnosis: DHS appeared to be a degenerative rather than inflammatory condition primarily affecting the connective tissue of the hind limb, especially at the dense collagen interfaces of the gastrocnemius. Although no evidence of neuropathy was found, this cannot definitively be ruled out as a potential cause.

Clinical relevance: A more standardised and systematic approach to investigating cases and recording case data is required to make robust inferences about the aetiology, risk factors, and treatment interventions for DHS.     

Pancreatic atrophy due to zinc toxicosis in two African ostriches (Struthio camelus)

Two of three captive adult African ostriches exhibited inappetance and weakness. In spite of treatment, the two birds were euthanized because of lack of clinical improvement. Postmortem examination demonstrated exocrine pancreatic degeneration, necrosis, and atrophy. Grossly, one ostrich had a markedly diminished pancreatic mass. Histologically, there was massive pancreatic acinar (exocrine) atrophy, marked interstitial fibrosis, and tubular complex formation in one animal, and the second ostrich had active pancreatic acinar necrosis. Toxicologic testing revealed markedly elevated liver zinc levels in the first two birds, whereas the third ostrich had normal serum levels of zinc and continues without apparent disease. This form of zinc toxicosis, while previously reported in different avian species, has been only rarely described in ratites.     

Reduced tongue tone associated with degeneration of the hypoglossal nerve nucleus in a horse with equine motor neuron disease

Equine motor neuron disease (EMND) is a condition characterised by generalised weakness and muscle atrophy associated with degeneration of motor neurons in the ventral horns of the spinal cord. Despite the frequent detection of cranial nerve nuclei pathology during post mortem examination, associated clinical signs are rarely reported. This report describes a case of EMND in a pony gelding that presented with clinical signs of diffuse neuromuscular weakness associated with marked flaccidity of the tongue, making differentiation from similar neuromuscular conditions, particularly botulism, extremely challenging.     

A clinical comparison of two injectable oxytetracycline preparations for the treatment of pneumonia in calves

Summary

The experiment was set up to make a clinical comparison in 140 pneumonic calves of two injectablc oxytetracycline formulations with different pharmacokinetic properties: Engcmycin^® 10% DD and Terramycin^® LA. The animals were examined clinically on the day of admission (day 0) and 1,2,3, 6 and 21 days thereafter. Calves were treated on day 0 with either Engemycin^® 10% DD (n=70) or Terramycin^® LA (n=70) at a dose of 20 mg/kg. If animals were not cured after one single injection, a second or even third injection was given at day 3 and day 6 respectively. No significant differences between the two treatment groups were found with regard to the number of injections needed for a complete cure, the evolution of dyspnoea, or the restoration of appetite. Thus both preparations gave comparable recovery rates. A difference between the two groups existed in the evolution of body temperature during the test period: the return to a normal body temperature occured more rapidly in the Engemycin^® 10% DD group. Regarding the tolerance aspects the degree of irritation depended in the preparation used. Calves treated with Engemycin^® 10% DD showed significantly less swelling of the injection site on day 1 then calves treated with Terramycin^® LA.     

Association of growth traits with a structural variation downstream of the KCNJ11 gene: a large population-based study in chickens

ABSTRACT

1. The potassium voltage-gated channel subfamily J member 11 gene (KCNJ11) is involved in the insulin secretion pathway. Studies have shown that mutation in this gene is associated with muscle weakness. The objective of the present study was to establish the association between KCNJ11 gene polymorphism and chicken growth performance and to analyse its expression pattern.

2. A novel 163-bp insertion/deletion (indel) polymorphism was identified in the region downstream of the KCNJ11 gene in 2330 individuals from ten populations by polymerase chain reaction (PCR). An F₂ resource population was used to investigate the genetic effects of the chicken KCNJ11 gene. Association analysis showed that the indel was significantly associated with chicken growth traits and that the phenotypic value of the ins-ins (II) genotype is higher than that of the ins-del (ID) and del-del (DD) genotypes.

3. Gene expression for different genotypes showed that birds carrying the II allele had a higher expression level than the DD genotypes. Analysis of tissue and spatiotemporal expression patterns indicated that the KCNJ11 gene was highly expressed in muscle tissues, with the highest levels in muscle tissue at one week of age, and that a 10% crude protein diet reduced the expression of this gene, average daily gain and muscle fibre diameter.

4. The results suggested that this novel 163-bp indel has the potential to become a new target for marker-assisted selection.