Probiotic treatment using Bifidobacterium lactis HN019 reduces weanling diarrhea associated with rotavirus and Escherichia coli infection in a piglet model

Background: Diarrhea associated with rotavirus and Escherichia coli is one of the major gastrointestinal problems faced by human infants. Using a pi-let model, the authors investigated the protective effectiveness of probiotic feeding against naturally acquired diarrhea in weanlings. Methods: Seventeen piglets were allocated into two groups balanced for live weight and litter of origin. The test group was administered Bifidobacterium lactis HN019 (10(9) colony-forming units (cfu)/piglet/d) orally until the end of the experiment; the control group did not receive probiotic treatment. After I week, animals were penned individually and weaned onto a diet for a weaner. The degree of subsequent diarrheal disease was monitored in both groups of animals, feed intake and live weight gain of the piglets were assessed, and blood and fecal samples were collected to measure concurrent systemic and gastrointestinal tract immunologic activity. Results: Compared with the controls, piglets that received B. lactis HN019 had a lower severity of weanling diarrhea and maintained a greater feed conversion efficiency during weaning. The protective effect of probiotic feeding was associated with lower concentrations of fecal rotavirus and E. coli, higher blood leukocyte phagocytic and T-lymphocyte proliferative responses, and higher gastrointestinal tract pathogen-specific antibody titers. Conclusions: These results show that dietary treatment using B. lactis HN019 can reduce the severity of weanling diarrhea associated with rotavirus and E. coli, possibly via a mechanism of enhanced immune-mediated protection. This study suggests that probiotic treatment may be an effective dietary means of preventing or limiting diarrhea in human infants.