A light microscopic and immunocytochemical study of the gastrointestinal tract of the ostrich (Struthio camelus L.)

Although the histological features and endocrine cells of the gastro-intestinal tract of the chicken have been well studied, little is known about these features of the gut of the ostrich. The present study was undertaken to elucidate the histology and peptide-storing endocrine cells of the ostrich. As a rule the histological features of the gastro-intestinal tract of the ostrich corresponded to that of the fowl. However, certain differences were observed. The superficial proventricular glands were simple, branched tubular glands, while the deep proventricular glands were restricted to a slipper-shaped area and extended into the muscularis mucosae. The gizzard had a variably developed muscularis mucosae, a feature that seems to be unique to the ostrich. The villi of the small intestine were long and branched profusely, forming a labyrinthine surface. No Paneth cells were observed. The mucosa of the ceca and the first part of the rectum was thrown in large circular folds, forming a compressed spiral. Numerous melanocytes were seen in the submucosa and the connective tissue around the bloodvessels of the muscle layers at the tips of the ceca. A well developed subserosa was present throughout the gastro-intestinal tract. Endocrine cells immunoreactive to somatostatin, glucagon, gastrin, bombesin, neurotensin, substance P and pancreatic polypeptide were detected in the gastro-intestinal tract of the ostrich. The topographical distribution of those endocrine cells immunoreactive to glucagon, bombesin, neurotensin and substance P differed from that of the chicken. The results of this investigation inferred that at least one of the gut peptides of the ostrich (secretin) to be structurally different from its counterparts in mammal and chicken. Molecular heterogeneity of somatostatin was observed in endocrine cells situated in the deep ventricular glands of the ostrich.     

Evaluation of antibody-ELISA and real-time RT-PCR for the diagnosis and profiling of bluetongue virus serotype 8 during the epidemic in Belgium in 2006

In 2006 bluetongue (BT) emerged for the first time in North-Western Europe. Reliable diagnostic tools are essential in controlling BT but data on the diagnostic sensitivity (Se) and specificity (Sp) are often missing. This paper aims to describe and analyse the results obtained with the diagnostics used in Belgium during the 2006 BT crisis. The diagnosis was based on a combination of antibody detection (competitive ELISA, cELISA) and viral RNA detection by real-time RT-PCR (RT-qPCR). The performance of the cELISA as a diagnostic tool was assessed on field results obtained during the epidemic and previous surveillance campaigns. As the infectious status of the animals is unknown during an epidemic, a Bayesian analysis was performed. Both assays were found to be equally specific (RT-qPCR: 98.5%; cELISA: 98.2%) while the diagnostic sensitivity of the RT-qPCR (99.5%) was superior to that of the cELISA (87.8%). The assumption of RT-qPCR as standard of comparison during the bluetongue virus (BTV) epidemic proved valid based on the results of the Bayesian analysis. A ROC analysis of the cELISA, using RT-qPCR as standard of comparison, showed that the cut-off point with the highest accuracy occurred at a percentage negativity of 66, which is markedly higher than the cut-off proposed by the manufacturer. The analysis of the results was further extended to serological and molecular profiling and the possible use of profiling as a rapid epidemiological marker of the BTV in-field situation was assessed. A comparison of the serological profiles obtained before, during and at the end of the Belgian epidemic clearly showed the existence of an intermediate zone which appears soon after BTV (re)enters the population. The appearance or disappearance of this intermediate zone is correlated with virus circulation and provides valuable information, which would be entirely overlooked if only positive and negative results were considered.     

The Influence of the Housing System on Salmonella Infections in Laying Hens: A Review

From 2012 onwards, housing of laying hens in conventional battery cages will be forbidden in the European Union and only enriched cages and non‐cage housing systems such as aviaries, floor‐raised, free‐range and organic systems will be allowed. Although this ban aims at improving the welfare of laying hens, it has also initiated the question whether there are any adverse consequences of this decision, especially with respect to the spread and/or persistence of zoonotic agents in a flock. A zoonotic agent that is traditionally associated with the consumption of eggs and egg products is Salmonella enteritidis. This paper provides a summary of the current knowledge regarding the direct and indirect effects of different housing systems on the occurrence and epidemiology of Salmonella in laying hen flocks.     

Secondary amyloidosis and renal failure in a captive California sea lion (Zalophus californianus)

A 16-yr-old, captive-born, female California sea lion (Zalophus californianus) was evaluated for intermittent lethargy, partial anorexia, and polydipsia of 2 wk duration. The animal was immobilized for physical examination. It was in thin body condition, with multifocal mucosal ulcerations over the caudal and ventral tongue. Blood was collected for hematology, serum chemistry, and leptospirosis serology. Serum chemistry revealed severe azotemia, mild hyperglycemia, and severe hyperphosphatemia. The animal went into cardiac arrest during recovery from anesthesia and died. On histopathology, abundant amorphous, finely fibrillar, eosinophilic material was deposited in the kidneys, and smaller amounts of the same material were found in the splenic and pancreatic vessels; these findings are consistent with systemic secondary amyloidosis. The animal also had chronic nephritis, which, coupled with renal amyloidosis, resulted in renal failure and death. Systemic amyloidosis should be considered as an additional differential diagnosis for renal failure in California sea lions.     

Effect of rumen-degradable protein balance deficit on voluntary intake, microbial protein synthesis, and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed corn silage-based diet

Two trials were conducted to evaluate the effect of rumen-degradable protein balance (OEB) deficit on voluntary intake (trial 1), microbial protein synthesis, and N metabolism (trial 2) in growing double-muscled Belgian Blue bulls. In trial 1, six bulls (339 +/- 26 kg of initial BW) were used in a replicated 3 x 3 Latin square and received a diet of 60% corn silage and 40% concentrate with ad libitum intake (DM basis). Three concentrates were formulated by adding urea at the expense of barley to give similar dietary contents of intestinal digestible proteins, NE for fattening, and fermentable OM, but with different levels of OEB. Thus, 2 levels of OEB deficit (-23.7 and -9.2 g of OEB/kg of DM) were compared with a diet providing a slight OEB surplus (5.3 g of OEB/kg of DM). Voluntary DMI decreased linearly (P = 0.02) with decreasing rumen-degradable protein balance. This decrease in intake could explain the linear decrease in ADG observed when negative OEB diets were fed. In trial 2, six bulls (304 +/- 12 kg of initial BW) with cannulas in the rumen and proximal duodenum were used in a replicated 3 x 3 Latin square and fed diets similar to those used in trial 1 at an intake level of 85 g of DM/kg of BW(0.75). Diurnal variations of ruminal NH(3)-N and plasma urea-N concentrations were greatly influenced by the level of OEB in the diet. No differences in NDF and starch degradation in the rumen, microbial N flow at the duodenum, or efficiency of microbial protein synthesis in the rumen were noted among the levels of OEB in diets. The reductions of the OEB value from 5.3 g/kg of DM to -9.2 g/ kg of DM and -23.7 g/kg of DM were associated with reductions of 26.5 and 48.8% in urinary N output. Absolute amounts of N retained by the bulls increased significantly with the level of OEB in diets. Indeed, 51.4% of the incremental supply of N was excreted between -23.7 and -9.2 g of OEB/kg of DM diets, and 74.6% of the incremental supply of N was excreted between -9.2 and 5.3 g of OEB/kg of DM diets. Feeding diets characterized by an adequate intestinal digestible protein supply and a OEB close to -10 g of OEB/kg of DM could be a feeding strategy to reduce N losses from the farm with little effect on the animal performance and voluntary intake. Reduced OEB may reduce N excretion in the environment but may also result in decreased N retention.     

Differences in hepatic cytochrome P450 activity correlate with the strain-specific biotransformation of medetomidine in AX/JU and IIIVO/JU inbred rabbits

Medetomidine is an α₂-adrenoceptor agonist with sedative and analgesic properties. Previously we demonstrated significant differences in the response to medetomidine between two inbred rabbit strains, denoted IIIVO/JU and AX/JU. The aim of the present study was twofold: first, to compare the hepatic CYP450 enzyme activities between these rabbit strains [ n  = 13(6♂♂,7♀♀)/strain]. To this end, liver microsomes were incubated with known fluorescent substrates for the major drug-metabolizing CYP450 isoforms. A comparison of the obtained results indicated significant gender differences as well as differences between the two rabbit inbred strains. Secondly, the biotransformation rate of medetomidine in liver microsomes of both rabbit strains was determined using liquid chromatography coupled to tandem mass spectrometry. The rate of hydroxymedetomidine and medetomidine carboxylic acid formation was found to be significantly higher in the AX/JU strain. Specific CYP2D and CYP2E inhibitors could decrease the formation of both metabolites. Significant correlations were found between the rate of biotransformation of medetomidine and the activities of CYP2D and CYP2E, as well as between CYP450 enzyme activities and the anaesthetic response to medetomidine.     

Transmission of methicillin resistant Staphylococcus aureus among pigs during transportation from farm to abattoir

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) in pigs at abattoirs is higher than in pigs sampled on farms. This study investigated whether MRSA negative pigs can become MRSA positive during transportation from the farm to the abattoir after exposure to other pigs and environmental sources of MRSA. Nasal swabs were collected from four batches of pigs during loading at the farm, on arrival at the abattoir and after stunning. Environmental wipes were taken from lorries after transporting pigs and from lairages after holding pigs. All pigs (n = 117) tested MRSA negative before transportation. On arrival at the abattoir, 12/117 (10.3%) pigs in two batches tested MRSA positive. In lorries that tested positive after transportation, the prevalence of MRSA positive pigs was 21.1%, whereas no MRSA was detected in pigs that had been transported in lorries that tested negative after transportation. At stunning, all batches and 70/117 (59.8%) pigs tested MRSA positive. Pigs can become MRSA positive in the short period of time during transportation from the farm to stunning at the abattoir.     

Neuritis of the cauda equina in a dog

This study presents the first case report of neuritis of the cauda equina in a dog, including characterisation of the inflammatory infiltrate. The dog in question, a 6-year-old Welsh springer spaniel, was presented with flaccid tail and faecal and urinary incontinence. The histological lesions included severe mononuclear cell infiltration of the nerve roots of the cauda equina and of the lumbar nerve roots. The infiltrate was composed of large numbers of T-lymphocytes and B-lymphocytes and small numbers of macrophages. Polymerase chain reactions of brain and spinal tissues were positive for Neospora caninum.