Application of 16S rRNA gene sequencing in evaluation of prebiotics or probiotics administration to restore gut dysbiosis induced by infectious bursal disease virus in broiler chickens

Infectious bursal disease (IBD) affects young chicks, inducing immune suppression, intestinal dysbiosis, poor growth performance, and mortalities. Our aim is to study the role of prebiotics and probiotics in overcoming dysbiosis related to IBD experimental infection. One-day-old chicks were divided into six groups (n=18) as four groups were given Enterococcus faecium (T1), Saccharomyces cerevisiae (T2), organic acids (T3), and symbiotic (T4) for five days at the 3rd-day post-infection. Groups 5 and 6 were considered negative control (NC) and positive control (PC). At 14 days old, all groups were challenged via eye drops with very virulent IBDV strain (MK088026), except the NC group. Feed conversion ratio (FCR), histopathological changes, and gut microbiome profile using 16srRNA gene sequencing were studied. Severe depletion of the bursa was observed in the PC group but was less severe in treated infected groups. 8 dpi, a significant decrease in cecum villous length (p<0.05) was observed in the PC group compared to the NC group, while it was corrected in treated infected groups. Cecal microbiome profile was studied on the 3rd and 8th-day post-infection (dpi). The IBD virus caused a decrease in the family Lachnospiraceae and family Ruminococcaceae compared to the NC group. In contrast, the treated infected groups showed an increase in the relative abundance of phylum Bacteroidetes, family Ruminococcaceae, and family Lachnospiraceae than the PC group. IBD infection caused poorer FCR than the NC group. In contrast, treated infected groups showed higher improvement in FCR than the PC group.