Cytokine gene expression profiles of bovine dendritic cells after interaction with Mycobacterium avium ssp. paratuberculosis (M.a.p.), Escherichia coli (E. coli) or recombinant M.a.p. heat shock protein 70

Mycobacterium avium paratuberculosis (M.a.p.) resides and replicates in macrophages. Many of the of immune mechanisms aiding M.a.p. survival in the host's cells are known. However, little is known about interactions of M.a.p. with dendritic cells (DC). As DC are important for the induction of protective immunity against infectious diseases, we investigated the interaction of M.a.p. with these cells. Quantitative real-time PCR (RT-PCR) was used to analyse differential expression of cytokine genes after 6 h and 24 h of incubation by immature DC that phagocytosed either M.a.p. or Escherichia coli (E. coli). We hypothesized that phagocytosis of E. coli would induce pro-inflammatory cytokines due to abundant presence of lipopolysaccharide (LPS) and that the cytokine expression profile induced by phagocytosis of live M.a.p. would differ. In addition we hypothesized that incubation of immature DC with rHsp70, an immunodominant antigen of M.a.p., would induce a similar profile of cytokine gene expression as phagocytosis of intact M.a.p. However, phagocytosis of both E. coli and M.a.p. resulted in a cytokine gene expression pattern representative of a (pro-)inflammatory reaction, dominated by strong induction of IL-12 gene expression, that was higher after 24 h than after 6 h of incubation, although the response to M.a.p. was less vigorous than to E. coli. Incubation with rHsp70 resulted in a more inhibitory type of cytokine gene expression, with delayed IL-12 gene expression and downregulation of the genes for IL-1beta and IL-6 after 24 h of incubation. We conclude that bovine DC produce an immuno-stimulatory, anti-mycobacterial response to infection with M.a.p., while Hsp70 potentially contributes to pathogen virulence by allowing the bacteria to invade the host cell.     

Survey on porcine trichinellosis in Ecuador

A survey on porcine trichinellosis was organised in Ecuador between 2000 and 2003. Blood samples were taken in slaughterhouses (study 1, n=2000; study 2, n=331) and in a remote village where pigs are free roaming (study 3, n=646) and examined by ELISA using excretory/secretory (E/S) antigens. Seven samples (0.35%) in study 1 and none of the samples of study 2 were serologically positive. Thirty-seven (5.72%) village pigs tested positive by E/S ELISA in study 3. Sero-positive results by the E/S ELISA in study 1 were confirmed by ELISA using beta-tyvelose antigen, and by immunoblot. Muscle samples taken from pigs slaughtered in the abattoir (study 2) and from animals that showed a positive serology in study 3 were examined by trichinoscopy and artificial digestion. These techniques failed to demonstrate the presence of muscle larvae. The results of this survey need confirmation, but suggest that Trichinella is present in Ecuador; however, prevalence and parasite burdens are likely to be very low. The likelihood of detecting trichinellosis are higher in traditional settings than in pigs raised on improved farms.     

High incidence of polyarteritis nodosa in the brains of culled sows

A total of 307 brains of purebred sows obtained from an abattoir were retrospectively examined. These sows were culled with reasons of reproductive failure, urogenital infections, or locomotor problems. The most common macroscopic lesions were cavitations or lacunae in the basal nuclei (9.1%, 28/307) and coarse and thickened leptomeninges with marked vessels (3.9%, 12/307). The most frequent microscopic lesion was polyarteritis nodosa (21.2%, 65/307), which was found in all 40 brains with the above-mentioned gross lesions and in all 25 brains with microscopic cerebral infarcts or cavitations. The affected arteries of polyarteritis nodosa were distributed primarily in the cerebral leptomeninges, basal nuclei, and internal and external capsules. Histopathologically, a characteristic change of the affected arteries was transmural fibrinoid necrosis with severe infiltration of mixed inflammatory cells; narrowing or occlusion of the lumen. The inflammatory cells were chiefly composed of lymphocytes, macrophages, and plasma cells, with a few eosinophils and occasional multinucleated giant cells. Polyarteritis nodosa was found at a high percentage in the brains from culled sows. It may result in cerebral ischemia, infarcts, and hemorrhage, and possibly play a role in the necessity for culling due to locomotor problems.     

Long-term risks and benefits of early-age gonadectomy in cats

OBJECTIVE: To evaluate the long-term risks and benefits of early-age gonadectomy, compared with traditional-age gonadectomy, among cats adopted from a large animal shelter. DESIGN: Retrospective cohort study. ANIMALS: 1,660 cats. PROCEDURE: Cats underwent gonadectomy and were adopted from an animal shelter before 1 year of age; follow-up was available for as long as 11 years after surgery (median follow-up time, 3.9 years). Adopters completed a questionnaire about their cats' behavior and medical history. When possible, the cats' veterinary records were reviewed. Statistical analyses were conducted to identify any associations between the occurrence of 47 medical and behavioral conditions and the cats' age at gonadectomy. RESULTS: Among male cats that underwent early-age gonadectomy (< 5.5 months of age), the occurrence of abscesses, aggression toward veterinarians, sexual behaviors, and urine spraying was decreased, whereas hiding was increased, compared with cats that underwent gonadectomy at an older age. Among male and female cats that underwent early-age gonadectomy, asthma, gingivitis, and hyperactivity were decreased, whereas shyness was increased. CONCLUSIONS AND CLINICAL RELEVANCE: Gonadectomy before 5.5 months of age was not associated with increased rates of death or relinquishment or occurrence of any serious medical or behavioral condition and may provide certain important long-term benefits, especially for male cats. Animal shelters can safely gonadectomize cats at a young age, and veterinarians should consider recommending routine gonadectomy for client-owned cats before the traditional age of 6 to 8 months.     

High Porcine Parvovirus Antibodies in Sow Herds: Prevalence and Associated Factors

Porcine parvovirus (PPV) is widespread among swine. Our objective was to determine the prevalence of loosely housed sow herds in Finland with at least one animal with high (infection level) PPV antibodies and to gather basic knowledge about vaccination practices. In addition, selected factors associated with high antibody levels found in sows were examined. Altogether, 247 animals were sampled in 21 randomly chosen loosely housed sow herds. Samples were analysed with the haemagglutination inhibition (HI) test. PPV proved to be common; in 17 farms (81%) at least one animal had a high titre (>1 : 512), and 44% of all animals sampled had a high titre. The vaccination programmes had many shortcomings. In the generalised estimation equations (GEE) population-averaged model developed, the factors found to have a significant (p < or = 0.05) effect on HI titres were herd size, parity of two or greater and storage of the vaccine vial after use. Non-returning rate, re-breeding interval and litter size did not differ between herds with no high HI titres (n = 4) and those with at least one high HI titre (n = 17).     

Inhibition of appressorial adhesion of Pyricularia oryzae to barley leaves by fungicides

The effects of rice blast fungicides known to inhibit melanisation or penetration on the adhesion of Pyricularia oryzae to the leaf surface of barley were investigated. Adhering appressoria were counted after shaking inoculated leaves vigorously with water. On untreated leaves, appressoria began to adhere at the time when appressorial melanisation was initiated. The number of adhering appressoria then increased gradually, and most were melanised. On chlobenthiazone-treated leaves, appressoria were not melanised and were easily detached from the surface. Similar results were obtained with tricyclazole. However, after treatment with tetrachlorophthalide or pentachlorobenzyl alcohol, which are also known to prevent penetration of P. oryzae, melanised appressoria still remained after shaking in water. It is suggested that appressorial melanisation in P. oryzae is involved in appressorial adhesion. The antipenetrant action of the melanin biosynthesis inhibitors chlobenthiazone and tricyclazole may be ascribed to the lack of adhesive intensity necessary to support the mechanical shearing of the cuticle of rice plants.     

Chemical and environmental factors driving germination of Solanum americanum seeds

Solanum americanum Mill. is a weed that occurs with a number of crops, and it is known for its high seed production and its staggered germination. The objective of this work was to evaluate the germination behavior of S. americanum seeds under the influence of chemical and environmental factors. In the laboratory, we tested the effect on germination of (i) constant and alternating temperatures, (ii) seed washing, (iii) exposure time and concentration of chemical treatments and (iv) seeding depth and soil covered with plant residue on seedling emergence. The variables analyzed were germination percentage, germination rate index, seedling emergence and length of the seedlings. The results indicated that alternating temperatures are the main way to promote germination of S. americanum; however, chemical treatments can help to increase the germination percentage and rate index. There was no increase in germination with seed washing, with the exception of KNO₃ application. A GA₃ concentration of 0.84 g L^?1 and an exposure time of 21.22 h in 0.2% of KNO₃ promoted the highest germination of S. americanum. Germination occurs when seeds remain on the soil surface and are not covered by crop residue.     

Development of an Isavirus minigenome system to study the function of the pocket RNA-binding domain of the viral nucleoprotein (NP) in salmon cells

The Isavirus is an orthomyxovirus with a genome composed of eight segments of negative single-strand RNA (−ssRNA). It has been proposed that the eight genomic segments of the Isavirus are organized as a ribonucleoprotein (RNP) complex called a minigenome, which contains all the viral RNA segments, a viral heterotrimeric polymerase and multiple copies of the viral nucleoprotein (NP). Here, we develop an Isavirus minigenome system and show the importance of the formation of active RNPs and the role of viral NP R189, R194, R302 and K325 residues in the NP RNA-binding domain in the context of RNPs. The results indicate it is possible to generate a minigenome in salmon cells, a composite ISAV RNPs with EGFP-based chimeric vRNA with heterotrimeric polymerase (PB1, PB2, PA) and NP protein using CMV-based auxiliary plasmids. It was also shown that NP R189, R194, R302 and K325 residues are important to generate viral mRNA from the constituted RNPs and a detectable reporter protein. This work is the first salmon cell-based minigenome assay for the Isavirus, which was evaluated by a bioinformatic and functional study of the NP protein in viral RNPs, which showed that correct NP-vRNA interaction is key to the functioning of RNPs.     

Compensatory growth and digestive enzyme activity of Litopenaeus vannamei submitted to feeding restriction in a biofloc system

Feeding restriction is a strategy in shrimp farming management that may promote compensatory growth after feeding is re‐established. This study aims to evaluate the effects of two feeding restriction regimens on the compensatory growth and digestive enzymes activity of Litopenaeus vannamei reared in biofloc system. Juvenile shrimp (0.46 ± 0.18 g) were stocked (320 individuals/m³) in 310 L tanks. The experiment comprised two phases: (a) Feeding Restriction (30 days) when shrimp were submitted to three feeding regimes, Control (fed daily), R1F1 (repetitively fasted one day and fed one day) and R2F1 (repetitively fasted 2 days and fed 1 day); and (b) Refeeding (28 days) when shrimp were fed daily. In the restriction phase, shrimp growth and digestive enzyme activities were reduced in R2F1 and R1F1. However, during the refeeding phase, enzyme activities and feed conversion improve significantly in R2F1 and R1F1. Control group attained higher final weight, but its final biomass was similar to R1F1. Litopenaeus vannamei exhibited partial compensatory growth, probably due to improved feed conversion efficiency driven by increased enzyme activity. It is possible to reduce feeding by 50% (R1F1) in biofloc systems for 28 days, without compromising the biomass produced at the end of a 30‐day refeeding period.     

Targeted species substitution in giant freshwater prawn trade revealed by genotyping

This study presents the molecular barcoding results of giant freshwater prawns and allied products collected from inland landing centres, markets and stores of Vembanad Lake (Kerala state, India) which is recognized as a natural abode for Macrobrachium rosenbergii. Prawns collected from landing centres of the lake could be easily identified as the above with their large size and morphological characters. There were certain ‘alien’ prawns and prawn products (headless shell on, peeled and deveined) traded in the markets and stores of this region as M. rosenbergii. Genotyping of all these samples using COI and 16S rRNA gene sequences confirmed the speciation of individuals from inland landing centres as M. rosenbergii, ‘alien’ prawns and certain prawn products as M. malcolmsonii. To ensure the same and to detect the presence of any other congeners of genus Macrobrachium inhabiting Vembanad Lake, additional homologous COI and 16S rRNA sequences available in NCBI were acquired and incorporated for molecular analyses. Results generated from NJ tree and genetic distance data confirmed the trade of non‐indigenous Macrobrachium species M. malcolmsonii in Kerala for the first time and its use as a species substituent for M. rosenbergii.