Lysozyme is a low-molecular-weight protein with antimicrobial properties. An experiment was conducted to investigate the response of piglets receiving a water-soluble lysozyme supplement (WSLS) after oral challenge with enterotoxigenic Escherichia coli (ETEC). A total of 36 individually housed weanling pigs were randomly allotted to 1 of the 4 treatments, with 9 replicates per treatment. Treatments were a control (CONT, no additive), antibiotic (AB; 2.5 g/kg of feed of antibiotic with chlortetracycline, sulfamethazine, and penicillin), and WSLS delivered in the drinking water at concentrations of 0.1% (WSLS 1) and 0.2% (WSLS 2). All pigs received a basal diet similar in composition and nutrients, except for pigs receiving the AB diet, which had an added antibiotic. Pigs were acclimated to treatments for a 7-d period to monitor growth performance. On d 8, blood samples were collected from each pig to obtain serum, and each pig was inoculated with 6 mL (2 x 109 CFU/mL) of ETEC solution. Pigs were monitored for another 7 d to assess incidences of diarrhea and growth performance, and then all pigs were euthanized to obtain intestinal tissue and digesta samples.
Treatments did not influence growth performance throughout the study. Greater ETEC counts were observed in the ileal mucosal scrapings (P = 0.001) and colonic digesta (P = 0.025) of pigs in the CONT group (4.75 and 4.42 log CFU/g of sample, respectively) compared with pigs in the AB (2.68 and 3.00 log CFU/g of sample) and WSLS 1 (2.47 y 2.90 log CFU/g of sample) groups. Pigs receiving AB and EG1 had greater (P < 0.05) small intestinal weights and ileal villus heights than pigs receiving CONT; however, the ileal villus height-to-crypt depth ratio was greater in pigs fed the AB diet (1.69) compared with those fed the CONT diet (1.34), whereas pigs receiving WSLS1 were intermediate. Pigs in the WSLS1 group showed greater (P < 0.001) serum tumor necrosis factor α and IL-6 concentrations before ETEC challenge; however, at 7 d postchallenge, pigs receiving WSLS2 showed the least (P < 0.05) circulating tumor necrosis factor α and IL-6 concentrations. Overall, better intestinal growth and development, as well as decreased ETEC counts on the intestinal mucosa and serum proinflammatory cytokines, suggest that WSLS can maintain gut health and function in piglets commensurate with antibiotics. However, it is noteworthy that at the largest dose tested, WSLS seemed to have a dramatic effect on proinflammatory cytokines but had a minimal or no effect on the other response criteria.
CM Nyachoti, E Kiarie,SK Bhandari, G Zhang, DO Krause. Weaned pig responses to Escherichia coli K88 oral challenge when receiving a lysozyme supplement 2012. Journal of Animal Science, 90:252-260. doi:10.2527/jas.2010-3596