Source of fiber influences growth, immune responses, gut barrier function and microbiota in weaned piglets fed antibiotic-free diets

摘要

This study examined the impacts of different fiber sources on growth, immune status and gut health in weaned piglets fed antibiotic-free diets. Sixty piglets (BW = 8.18?±?1.35?kg) were assigned to 3 dietary treatments based on BW and gender in a randomized complete block design (5 replicates/treatment and 4 piglets [2 barrows and 2 gilts]/replicate): (1) an antibiotic-free diet (control, CON); (2) CON? ?6% wheat bran (WB); (3) CON? ?4% sugar beet pulp (SBP). Dietary WB supplementation tended to increase ADG compared with CON from d 1 to 14 ( P =?0.051) and from d 1 to 28 ( P =?0.099). Supplementation of WB increased ( P ?0.05) G:F compared with CON and SBP from d 1 to 14 and from d 1 to 28. Compared with CON, the addition of WB reduced ( P ?0.05) diarrhea rate from d 1 to 14 and tended ( P =?0.054) to reduce diarrhea rate from d 1 to 28. The addition of WB decreased ( P ?0.05) serum diamine oxidase activity on d 14, and up-regulated ( P ?0.05) ileal mRNA levels of occludin on d 28 when compared with CON. Piglets fed WB showed decreased ( P ?0.05) serum interleukin-6 levels compared to those fed SBP and decreased ( P ?0.05) ileal interleukin-8 levels compared to those fed CON and SBP on d 28. Supplementation of WB increased ( P ?0.05) serum levels of immunoglobulin A (IgA), IgG and IgM compared with SBP on d 14, and increased ( P ?0.05) the levels of serum IgA and ileal sIgA compared with CON and SBP on d 28. Piglets fed WB showed an enhanced ( P ?0.05) α-diversity of cecal microbiota than those fed SBP, while piglets fed SBP showed reduced ( P ?0.05) α-diversity of cecal microbiota than those fed CON. Compared with CON, the addition of WB elevated ( P ?0.05) the abundance of Lachnospira and cecal butyric acid level. Piglets fed WB also showed increased ( P ?0.05) abundances of Lachnospira and unclassified_f_Lachnospiraceae compared with those fed SBP. Collectively, the supplementation of WB to antibiotic-free diets improved performance, immune responses, gut barrier function and microbiota compared with the CON and SBP fed piglets. Therefore, supplementing weaned piglets with WB was more effective than SBP.