In our previous study, the applicability of
chitosan-
alginate microcapsules for oral delivery of egg yolk
immunoglobulin (
IgY) was established in a simulated gastrointestinal tract environment. The objective of the present study was to evaluate the protective efficacy of microencapsulated
IgY against K88+ ETEC (enterotoxigenic Escherichia coli)-induced
diarrhea in 40-day-old pigs. Groups of pigs orally challenged with 10(11) cfu/mL of K88+ ETEC were fed with non-encapsulated
IgY, microencapsulated
IgY and
aureomycin-treated feed respectively. The clinical response of each group was monitored and evaluated in terms of
lethargy, inappetence, occurrence of
diarrhea, fecal consistency score,
weight loss and recovery rate. The results showed that treatment of infected pigs with microencapsulated
IgY significantly (P<0.05) reduced the K88+ ETEC-induced
diarrhea at 24 h post-
infection. In contrast, the
diarrhea-reducing effect of non-encapsulated
IgY was delayed (only evident after 72 h) while
normal saline-treated pigs (controls) continued to suffer from
diarrhea and
dehydration. Similarly,
weight gain in microencapsulated
IgY-treated pigs was better and significantly different (P<0.05) than in non-encapsulated
IgY and saline-treated controls. Collectively, these results support previous in vitro observations showing that
chitosan-
alginate microcapsules can be an effective method of protecting
IgY from gastric inactivation, enabling its use for the widespread prevention and control of enteric diseases.