Construction and immunogenicity studies of recombinant fowl poxvirus containing the S1 gene of Massachusetts 41 strain of infectious bronchitis virus

The spike 1 (S1) surface glycoprotein of infectious bronchitis virus (IBV) is the major inducer of the generation of virus neutralizing antibodies, and the administration of purified S1 has been shown to elicit a protective immune response against virulent virus challenge. On the basis of these observations, recombinant fowl poxvirus (rFPV) containing a cDNA copy of the S1 gene of IBV Mass 41 (rFPV-S1) was constructed and its immunogenicity and vaccine potential were evaluated. Initially, rFPV-S1 was shown to express the S1 in vito by indirect immunofluorescence staining and western blot analyses. Later, in vivo expression was demonstrated by the detection of IBV-specific serum immunoglobulin G and neutralization antibodies in the sera of chickens immunized with rFPV-S1. That the recombinant virus elicited anti-IBV protective immunity was indicated by the manifested, relatively mild clinical signs of disease, decreased titers of recovered challenge virus, and less severe histologic changes of the tracheas in virulent IBV Mass 41-challenged chickens previously receiving rFPV-S1 as compared with parental fowl poxvirus (FPV)-vaccinated control birds. In contrast, chickens immunized with either recombinant or parental FPV were resistant to a subsequent virulent FPV challenge. As to a preferred method of immunization, wing web administration appeared to be superior to the subcutaneous route because a greater percentage of birds vaccinated by the former protocol exhibited an anti-IBV humoral immune response. Thus, rFPV-S1 has potential as a poultry vaccine against both fowl pox and infectious bronchitis.     

罗非鱼湖病毒病传入风险分析

为评估罗非鱼湖病毒（tilapia lake virus,TiLV）跨境传入风险,按照OIE传入风险评估框架,从危害识别、风险评估及风险管理3个方面,开展了TiLV跨境传入风险分析,并提出了相应的风险控制措施。分析认为：活的敏感鱼类（包括亲鱼、鱼卵和鱼苗）,用做鲜活饵料的鱼类（野杂鱼）及冰冻和冰鲜的敏感鱼类（包括去除内脏的鱼肉）TiLV传入风险较高,而敏感鱼加工类产品、非敏感鱼类（包括活的和其他形式的产品）及运输活鱼的水、包装、运输工具和用具等传入风险较低。建议不从疫区进口高风险产品,对于低风险产品可以自由贸易,而对运输活鱼的水、包装、运输工具和用具等要进行强制常规消毒。     

Effects of three major protein sources on performance,gut morphology and fermentation characteristics in broilers

ABSTRACT

1. This study determined the effects of three protein sources (PS), each at two digestibility crude protein (DCP) levels, on performance, gut morphology and fermentation characteristics in the hindgut of broilers.

2. It was hypothesised that broilers fed ingredients high in indigestible CP, i.e. rapeseed meal (RSM) or maize gluten (MG), could potentially cause reduced growth, impaired gut health, and more protein fermentation products in caecal digesta. Increasing the DCP level in each of the indigestible CP diets may compensate for these detrimental effects.

3. In total, 288 one-d-old male Ross 308 broilers were used in a completely randomised 3 × 2 factorial design, with six replicate pens per treatment. Three PS: soybean meal (SBM), rapeseed meal (RSM) or maize gluten (MG), and two DCP levels: 15.8 and 17.2% were used.

4. Broilers fed SBM had increased feed intake and BWG and improved FCR compared with those fed RSM and MG diets. Broilers fed high DCP had better performance compared with those on low DCP. No significant effects of PS or DCP level were found on gastrointestinal tract development, caecal ammonia or volatile fatty acid concentrations.

5. Broilers fed SBM had longer villi, smaller crypts and increased villus height to crypt depth ratio compared with those fed RSM and MG diets. Broilers fed RSM diet had a lower caecal pH, and had 16.5% and 14.9% more branched chain fatty acid contents in caecal digesta compared with those fed SBM and MG diets, respectively, indicating more proteolytic fermentation.

6. Replacing SBM by RSM and MG negatively affected growth performance and gut morphology. Hindgut protein fermentation was substantially increased in RSM fed birds.

7. To a certain extent, retarded growth performance in RSM and MG fed birds could be counterbalanced by increasing the dietary level of digestible CP.     

In-hospital development of an aorto-cardiac fistula in a Warmblood gelding with chronic renal disease

A 20-year-old Warmblood gelding presented for evaluation and treatment of ventral oedema and azotaemia of unknown aetiology. On presentation, a diastolic heart murmur was appreciated and echocardiography revealed moderate aortic insufficiency due to chronic degenerative valve disease. The horse was hospitalised and failed to respond to oral and i.v. fluids and diuretics. Following discontinuation of all fluid and diuretic therapy, the horse became acutely agitated and developed monomorphic ventricular tachycardia. The ventricular tachycardia spontaneously converted to normal sinus rhythm, however the heart murmur changed in timing to a right basilar continuous murmur and bounding jugular pulses were noted. Repeat echocardiogram revealed an aorto-cardiac fistula with dissection into the basilar interventricular septum and left-sided chamber volume overload that was not previously present. Attempts at stabilisation were unsuccessful and euthanasia was elected. Post-mortem examination confirmed chronic renal disease of unknown aetiology in addition to an aorto-cardiac fistula originating from the right sinus of Valsalva with subsequent dissection into the basilar interventricular septum.     

Liver of the fish Gymnotus inaequilabiatus and nematode larvae infection: Histochemical features and expression of proliferative cell nuclear antigen

Histopathological lesions due to third‐larval stage of nematode Brevimulticaecum sp. within the liver of a subpopulation of 31 Gymnotus inaequilabiatus from the Pantanal Region (Brazil) were studied with histochemical and immunohistochemical methods. In 93.5% of fish, livers harboured nematode larvae and the intensity of infection ranged from 8 to 293. In livers with highest number of larvae, the hepatic tissue was occupied primarily by the nematodes. Each larva was encircled by focal inflammatory granulomatous reaction. Within the thickness of the granuloma, three concentric layers were recognized: an inner layer of densely packed epithelioid cells, a middle layer of mast cells (MCs) entrapped in a thin fibroblast‐connective mesh and an outer layer of fibrous connective tissue with fibroblasts. Epithelioid cells and fibroblasts within the thickness of the granuloma wall were positive for proliferative cell nuclear antigen (PCNA). Moreover, several hepatocytes in infected liver were immunoreactive to PCNA. Occurrence of rodlet cells and MCs in parenchyma, in close proximity to the encysted nematode larvae and near the blood vessel of infected liver, was observed. Macrophage aggregates (MAs) were numerous within the granulomas and scattered in parenchyma of the infected liver. High quantity of haemosiderin was encountered in MAs and hepatocytes of infected liver.     

Study of the duration and distribution of equine influenza virus subtype 2 (H3N8) antigens in experimentally infected ponies in vivo.

The purpose of this experiment was to study the duration and distribution of equine influenza virus in actively infected ponies over a 3 wk period. Pony foals (6-8 mo old) were infected experimentally by nebulizing equine influenza subtype-2 virus ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals (n = 6) had a febrile response, a deep hacking cough and mucopurulent nasal discharge for 7 to 10 d. The virus was isolated from nasopharyngeal swabs of all the ponies 3 and 5 d after infection and all the ponies seroconverted to the virus. Samples were taken from the nasopharynx, mid-trachea and the mainstem bronchus with cytology brushes through an endoscope as well as from bronchoalveolar lavage fluid. On days 3 to 7 post-infection, ciliacytophtorea (the presence of cilia and ciliated plates separated from columnar epithelial cells) was recognized on routine cytological stain. Indirect immunoperoxidase staining utilizing polyclonal antibodies demonstrated viral antigen in intact and fragmented ciliated epithelial cells and in fragments of ciliated plates. The infected cells and cell fragments were particularly evident on days 3 and 5 post-infection in the nasopharynx, mid-trachea and mainstem bronchus and on days 3 to 7 post-infection in the bronchoalveolar lavage samples. On days 7 and 21 post-infection, viral antigen was identified in vacuoles of alveolar macrophage-like cells collected by bronchoalveolar lavage. It can be concluded from this study that equine influenza virus can infect not only the upper airways but also the bronchial epithelium and that viral antigen can persist up to 21 d post-infection.     

Development and evaluation of an endoscopic technique permitting rapid visualization of the cardiac region of the porcine stomach.

Our study was designed to ascertain whether a flexible videoscope could be used to efficiently monitor ulcers of the pars esophagea in a large group of grower-finisher swine. Gastroscopy was performed on 2 separate occasions in 32 pigs following anesthesia with intravenous pentobarbital, and ulcers of the pars esophagea were subjectively graded. The pigs were then necropsied. Grades from the second endoscopic examination were compared for agreement with grades derived from gross inspection of the pars esophagea at necropsy, and with grades derived from histopathologic examination of sections of the same region. The pars esophagea was adequately visualized in all endoscopic examinations. The average duration of each examination, from anesthetic induction, was approximately 8 min. Gastroscopy permitted appreciation of a wide range of focal and diffuse superficial and deep ulcerative lesions of the pars esophagea, but failed to unequivocally identify parakeratosis of the pars esophagea. Agreement between endoscopic and subsequent necroscopic and histopathologic gradings of ulcerations was poor. We concluded that the use of a flexible videoscope permitted rapid inspection of the pars esophagea, and was therefore a practical method of experimentally monitoring the progression of spontaneous gastric ulcers in pigs. We also postulated that the poor agreement between endoscopic and postmortem findings occurred because endoscopy was possibly more sensitive at detecting small and superficial ulcerations. However, further studies are needed to verify the accuracy of endoscopic diagnosis of gastric ulcers in the live pig.     

Dysfibrinogenemia or afibrinogenemia in a Border Leicester lamb.

Hereditary fibrinogen deficiency is a rare condition in all species. Measurement of plasma fibrinogen should indicate low levels. Specific factor assays and pedigree analysis are essential in establishing a definitive diagnosis of the hereditary deficiency. Differentiation between afibrinogenemia, hypofibrinogenemia, and dysfibrinogenemia requires sophisticated techniques and assistance from a specialized laboratory.