Search

Abstract: We have used selected rabbit anti-human polyclonal antibodies as an example of useful and easily available tools for studies on immune system structure and development in important veterinary species, many of which also represent animal models in biomedicine. The cocktail of anti-human Igκ-FITC/anti-Igλ-RPE F(ab′)2 fragments was used for two-colour and, in combination with the cross-reactive anti-CD79α monoclonal antibody HM-57, for three-colour flow cytometry of canine, feline, bovine and porcine peripheral B-cells. A possible application of such immunoreagents in studies on primary B-cell differentiation has been suggested in pigs; the same approach can be used in other species of interest. Rabbit anti-human lactoferrin-FITC F(ab′)2 fragment was used for visualizing neutrophils in dogs, pigs and cattle and an application for two-colour immunophenotyping of canine granulocyte subsets has been designed. Affinity isolated rabbit anti-human CD3 and anti-human TdT have been shown to represent a ready-to-use tool for in situ studies on primary T-lymphopoiesis in pigs with possible extensions both to the B-lineage development in pigs and other animal models. Altogether, our study show that carefully selected polyclonal antibodies available on the market may possess broad cross-reactivity with important applications in veterinary research. [Copyright &y& Elsevier]

Abstract: The aim of this study was to investigate the effects of dietary supplementation of weaned piglets with natural bentonite on post-weaning diarrhoea (PWD), intestinal colonization by enterotoxigenic Escherichia coli (ETEC) and intestinal histopathology, growth performance, and haematological and serum biochemical parameters. The piglets in our study were obtained from a traditional farm with a high prevalence of PWD. The effects of dietary bentonite were tested on 50 weaned piglets in two trials. Piglets were allocated to two dietary groups, control and bentonite, receiving a basal diet with or without bentonite supplementation at levels of 1% and 2% for 21days. In vitro testing of antibacterial activity of bentonite against ETEC O149:F4:LT showed that it had no ability to reduce bacterial plate counts. Dietary bentonite has not been effective in reducing the occurrence and duration of diarrhoea or mortality rates, although faecal ETEC shedding decreased (P=0.004) in bentonite fed piglets. Histopathological examinations of the intestines demonstrated that 2% bentonite exerted a protective effect on the small intestinal mucosa, the inflammation of which was milder. Also, a beneficial effect on regenerative processes following intestinal infections was observed. A significantly lower leukocyte count (P=0.048) in peripheral blood indicated that the infection in bentonite-fed piglets was less severe. Exposure of piglets to bentonite did not significantly affect their post-weaning growth performance. The addition of bentonite to diet had no adverse effect on biochemical blood parameters in piglets. The present study shows that the use of natural untreated bentonite as a feed additive for weaned piglets can be considered safe, but its final efficacy in preventing the occurrence and severity of PWD is low. [Copyright &y& Elsevier]

Abstract: The protective role of hyperimmune serum in the prevention of Haemophilus parasuis infections in post-weaned piglets was assessed by experimental challenge. The hyperimmune serum was obtained from a pig vaccinated with a commercial vaccine against Glässer’s disease. Thirty-eight weaned piglets were divided into four groups: three groups were immunised intramuscularly with 10ml of hyperimmune serum and one group consisted of unimmunised control animals. All piglets were subsequently infected intraperitoneally with H. parasuis serotype 5 at different times after immunisation. The use of hyperimmune serum provided the piglets with partial protection against experimental infection. The levels of protection indirectly depend on time between serum inoculation and challenge infection. The best protection of piglets against experimental infection was obtained in the group immunised 1week before inoculation; the same group in which the highest levels of antibodies were detected at the time of challenge. [Copyright &y& Elsevier]