Evaluation of the effectiveness of hyperimmunized chicken eggs for controlling Lawsonia intracellularis infection in growing swine

摘要

Porcine proliferative enteropathy (PE) or ileitis, caused by the obligate intracellular bacterium Lawsonia intracellularis (LI), is an important and widespread disease of late nursery to grower/finisher pigs and replacement gilts. A recent National Animal Health Monitoring System (2000) report implicated PE as the most common disease problem on sites with grower/ finisher pigs. This infection is transferred via the fecal-oral route, and may pass from sow to suckling piglets or sow to naive gilts. There is high morbidity with the disease in the young pig, characterized by a large variability in market weights, and high mortality associated with the infection of the gilt population. Infected piglets may carry or transmit the organism after weaning, resulting in infection and disease of the grower/finisher herd. Currently, methods to control this disease include long-term use of approved feed-grade antibiotics (tylosin, lincomycin, chlortetracycline/BMD, tiamulin) and vaccination (Enterisol ileitis~(R). Existing methods of control are either non-preventative with regards to Lawsonia infection or relatively costly. Furthermore, use of antimicrobial alternatives represents a more desirable management technique due to public health concerns over the potential antibiotic residues in meat and the risk of antibiotic resistance in organisms which are potentially pathogenic for humans. The purpose of this study was to determine if Li-specific antibodies produced in chicken eggs and fed in the diet of grow/finisher pigs reduce the incidence and severity of clinical signs, fecal shedding, and intestinal lesions (gross and histological) characteristic of PE after challenge with LI.