Seroprevalence study of bovine neosporosis in Mexico.

An indirect enzyme-linked immunosorbent assay was used to obtain epidemiologic information on bovine neosporosis in dairy herds of the Mexican central plateau. Sera were collected from 1,003 cows from 50 dairy herds. Forty-three herds (group A) had been experiencing a high abortion rate. The abortion rates for the remaining 7 herds (group B) were within normal limits for Mexico. Five-hundred sixty-one (56%) of the 1,003 sera were positive. The seroprevalence of Neospora caninum antibodies was 72% (95% CI = 68-75%) in group A and 36% (95% CI = 31-40%) in group B. These results clearly show that infection with N. caninum is widespread in Mexican dairy herds, as indicated by seropositive cows in group A and group B herds at the time of the sample collection.     

Effect of feed intake level and dietary protein content on the body temperature of pigs housed under thermo neutral conditions

Feed intake and diet composition appear to affect the body temperature of pigs. Two trials were conducted to analyse the effect of feed intake level and dietary protein content on the intestinal temperature (IT) of pigs housed under thermo neutral conditions. Ten pigs (64.1 ± 1.3 kg initial body weight) fitted with an ileal cannula were used. A thermometer set to register the IT at 5‐min intervals was implanted into the ileum through the cannula. In both trials, the ambient temperature ranged from 19.1 to 21.6°C and the pigs were fed at 07:00 and 19:00 hr (same amount each time). In trial 1, the pigs were fed daily 1.2 or 1.8 kg of a wheat–soybean meal diet. The IT followed a similar pattern along a 24‐hr period regardless the feed intake level. The IT rapidly increased up to 0.61 and 0.74°C after the morning meal and up to 0.53 and 0.47°C after the evening meal in pigs fed 1.2 and 1.8 kg/d respectively. The postprandial IT was higher in pigs fed 1.8 kg after each meal (p < .05). In trial 2, pigs were fed daily 1.8 kg of a low (11%) or a high (22%) crude protein diet. The IT followed a similar pattern along the 24‐hr period regardless the dietary protein level. The postprandial IT did not differ between pigs fed the low protein or the high protein (p > .10). The IT rapidly increased up to 0.66 and 0.62°C after the morning meal in pigs fed the high‐ and low‐protein diet (p < .05), but there was no change after the evening meal (p > .10). In conclusion, the feed intake level affected the IT of pigs housed under TN conditions, but the dietary protein content had no effect.     

Improvements to the hemagglutination inhibition test for serological assessment of recombinant fowlpox-H5-avian-influenza vaccination in chickens and its use along with an agar gel immunodiffusion test for differentiating infected from noninfected vaccinated animals

In general, avian influenza (AI) vaccines protect chickens from morbidity and mortality and reduce, but do not completely prevent, replication of wild AI viruses in the respiratory and intestinal tracts of vaccinated chickens. Therefore, surveillance programs based on serological testing must be developed to differentiate vaccinated flocks infected with wild strains of AI virus from noninfected vaccinated flocks in order to evaluate the success of vaccination in a control program and allow continuation of national and international commerce of poultry and poultry products. In this study, chickens were immunized with a commercial recombinant fowlpox virus vaccine containing an H5 hemagglutinin gene from A/turkey/Ireland/83 (H5N8) avian influenza (AI) virus (rFP-H5) and evaluated for correlation of immunological response by hemagglutination inhibition (HI) or agar gel immunodiffusion (AGID) tests and determination of protection following challenge with a high pathogenicity AI (HPAI) virus. In two different trials, chickens immunized with the rFP-H5 vaccine did not develop AGID antibodies because the vaccine lacks AI nucleoprotein and matrix genes, but 0%-100% had HI antibodies, depending on the AI virus strain used in the HI test, the HI antigen inactivation procedure, and whether the birds had been preimmunized against fowlpox virus. The most consistent and highest HI titers were observed when using A/turkey/Ireland/83 (H5N8) HPAI virus strain as the beta-propiolactone (BPL)-inactivated HI test antigen, which matched the hemagglutinin gene insert in the rFP-H5 vaccine. In addition, higher HI titers were observed if ether or a combination of ether and BPL-inactivated virus was used in place of the BPL-inactivated virus. The rFP-H5 vaccinated chickens survived HPAI challenge and antibodies were detected by both AGID and HI tests. In conclusion, we demonstrated that the rFP-H5 vaccine allowed easy serological differentiation of infected from noninfected birds in vaccinated populations of chickens when using standard AGID and HI tests.     

Effects of no‐take area size and age of marine protected areas on fisheries yields: a meta‐analytical approach

Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.     

Haemolymph metabolic variables in relation to eyestalk ablation and gonad development of Pacific white shrimp Litopenaeus vannamei Boone

The present study analyses some biochemical variables in haemolymph proposed as predictive indicators of the maturation capability following eyestalk ablation. Haemolymph of captive females was obtained before and 8 days after eyestalk ablation, and levels of haemocyanin, total proteins, glucose, lactate, cholesterol, triacylglycerides and vitellogenin were determined. Biochemical variables were also analysed in the hepatopancreas at the end of the experiment. Females were grouped as immature (previtellogenic stage) and mature (vitellogenic and cortical stages) based on histological analysis done 8 days after eyestalk ablation. To analyse haemolymph variables before eyestalk ablation in relation to maturation capability, immature females were classified as those with a low maturation capability and mature females as those with a high maturation capability. Females of high maturation capability had significantly higher vitellogenin levels before eyestalk ablation than females of low maturation capability. No significant differences were found for the other biochemical variables. Vitellogenin was also higher in mature than in immature females at the end of the experiment. These results indicate that vitellogenin levels in haemolymph could be used as possible predictive criteria of maturation capability, possibly because they reflect the degree of ovarian development at the time of eyestalk ablation.     

Characterization of common bean wild populations for their in situ conservation in Northwestern Argentina

In situ conservation of wild species is a method of conservation that allows keeping populations in their natural environments, and set the strategies for maintaining the natural populations. The Active Bank of Northwestern Argentina (BANOA) is in charge of the in situ conservation of wild populations of common bean (Phaseolus vulgaris L.) in Northwestern Argentina (NOA), and has an ex situ collection of 401 landraces and 221 wild accessions from the NOA. We evaluated the phenotypic diversity of 68 common bean wild populations from the NOA both in protected and unprotected areas, finding a moderate variation among them. Ten phenotypic reproductive characteristics related to pod and seed displayed significant differences in the analysis of variance; these traits together with the seed weight were the basis for the multivariate analysis. The cluster analysis ordered the populations in 12 groups but trends in geographical distribution or phenotypical variation were not recognized. For the conservation in situ of the wild bean populations, their diversity should be considered. Two types of populations can be highlighted: (i) candidates for in situ conservation in order to preserve the novel variation generated by convergence with cultivated sympatric germplasm (populations 433, 437, 471, 509, 513 and 517) and (ii) those whose phenotype represents clearly the wild status and should be preserved in situ as such in their current status (populations 480, 495, 496, 525 and 533).     

Phenotype and function of murine discrete Peyer's patch macrophage derived - dendritic cells

The phenotype and function of peritoneal cavity macrophage-derived dendritic cells (PEC-DC) was previously reported. In this study we have gone further in using our established culture system to generated discrete Peyer's patch dendritic cells (DPP-DC) from murine discrete Peyer's patch macrophages (DPP-M?), following stimulation with granulocyte macrophage colony stimulating factor (GM-CSF) plus interleukin 4 (IL-4) for 7 days. DPP-M? from murine small intestines were obtained by mechanical disruption of discrete Peyer's patches (DPP), followed by metrizamide density gradient centrifugation to remove Peyer's patch resident DC and debri, after which an overnight adherent step in tissue culture medium was carried out for macrophage enrichment. Characterization of the generated DPP-DC was carried out using well-established criteria of morphology, expression of membrane antigens and capacity for antigen presentation. Dendritic cells expressed DEC-205, F4/80 and CD34 at high levels, but exhibited very low CD11c levels. They were shown to present soluble protein antigen to CD3(+) spleen T cells. A comparison of the surface antigen expression in the progenitor DPP-M? population and the generated DPP-DC showed a significant decrease in MHC class II levels and a marked down regulation of the co-stimulatory molecule CD86 (B7-2). High expression of the haemopoietic progenitor marker CD34 indicates that the generated DC, possess a haemopoietic rather than myeloid origin. Taken together, these results may provide a better understanding of the complex network regulating mucosal immune responses.     

Vaccination of pigs with the S48 strain of Toxoplasma gondii – safer meat for human consumption

As clinical toxoplasmosis is not considered a problem in pigs, the main reason to implement a control strategy against Toxoplasma gondii (T. gondii) in this species is to reduce the establishment of T. gondii tissue cysts in pork, consequently reducing the risk of the parasite entering the human food chain. Consumption of T. gondii tissue cysts from raw or undercooked meat is one of the main sources of human infection, with infected pork being considered a high risk. This study incorporates a mouse bioassay with molecular detection of T. gondii DNA to study the effectiveness of vaccination (incomplete S48 strain) in its ability to reduce tissue cyst burden in pigs, following oocyst (M4 strain) challenge. Results from the mouse bioassay show that 100% of mice which had received porcine tissues from vaccinated and challenged pigs survived compared with 51.1% of mice which received tissues from non-vaccinated and challenged pigs. The presence (or absence) of T. gondii DNA from individual mouse brains also confirmed these results. This indicates a reduction in viable T. gondii tissue cysts within tissues from pigs which have been previously vaccinated with the S48 strain. In addition, the study demonstrated that the main predilection sites for the parasite were found to be brain and highly vascular muscles (such as tongue, diaphragm, heart and masseter) of pigs, while meat cuts used as human food such as chop, loin, left tricep and left semitendinosus, had a lower burden of T. gondii tissue cysts. These promising results highlight the potential of S48 strain tachyzoites for reducing the number of T. gondii tissues cysts in pork and thus improving food safety.