Gastric Ulceration and Immune Suppression in Weaned Piglets Associated with Feed-Borne Bacillus cereus and Aspergillus fumigatus

As a multifactorial cause, gastric ulceration-mediated diarrhea is widely prevalent in the weaned piglets, impairing pig health and economic benefits. With full implementation of antibiotic stewardship programs in China, ( ) and ( ) were identified frequently in porcine feedstuffs and feeds of the animal industry. Association between feed-borne and frequent diarrhea remains unclear. In the present study, we conducted a survey of and from feeds and feedstuffs in pig farms during hot season. Interestingly, , , and were isolated and identified from piglets' starter meals to sow feeds, accounting for 56.1%, 23.7%, 13.7% and 6.5%, respectively. Obviously, both and were dominant contaminants in the survey. In an in vitro study, Deoxynivalenol (DON) contents were determined in a dose-dependent manner post fermentation with (405 and DawuC). Subsequently, 36 weaned piglets were randomly assigned to four groups and the piglets simultaneously received the combination of virulent (Dawu C) and while animals were inoculated with (Dawu C), or PBS as the control group. Clinically, piglets developed yellow diarrhea on day 5 and significant reductions of relative body weight were observed in the group, and co-infection group. More importantly, IgG titers against (CSFV) and Porcine epidemic diarrhea (PED) were reduced dramatically during 14-day observation in co-infection group, the (Dawu C) group or the group. However, lower Foot and mouth disease (FMD) -specific antibodies were reduced on day 7 compared to those of the control group. Additionally, lower lymphocyte proliferations were found in the group and the co-infection group compared to the control group. Postmortem, higher lesions of gastric ulceration were observed in the group and the co-infection group from day 7 to day 14 compared with those of the group and the control group. Compared to the group, higher DON contents were detected in the stomach inoculated with and the co-infection with . In conclusion, our data support the hypothesis that might be associated with severe diarrhea by inducing gastric ulcerations and might aggravate immune suppression, threating a sustainable swine industry. It is urgently needed to control feed-borne contamination.