Coated Sodium Butyrate Effect On Rabbit Intestinal Health And Its Protective Effect Research Foe Coccidiosis

Animal growth and breeding efficiency rely greatly on the intestinal health of animals. Coccidiosis is a common disease in bred rabbits; it causes serious damage to the intestinal health of these animals and may even be fatal. A new feed additive coated sodium butyrate (CSB), can improve intestinal morphology, maintain the intestinal barrier, and regulate the balance of the intestinal flora. Thus, CSB plays an important role in ensuring intestinal health and preventing disease in animal husbandry. In order to provide a theoretical basis and guide for the use of CSB as a feed additive in production practices and to prevent intestinal disease. We first studied the effects of CSB on the intestinal health of uninfected rabbits. We recorded data on the effects of this additive on growth performance, intestinal morphology, the activity and amount of digestive enzymes, intestinal cytokine levels, intestinal flora, blood biochemistry, and antioxidant indicators in healthy, weaning rabbits. Next, we investigated the effects of dietary CSB on coccidiosis in rabbits, we orally infected rabbits with Eimeria magna and collected the following data:weight change, oocyst per gram of feces (OPG), intestinal morphology, intestinal cytokine levels, serum levels of soluble CD4 (sCD4) and soluble CD8 (sCD8), and the immune organ index.Experiment one:To study the effects of CSB on intestinal health in rabbits. Thirty-two healthy, weaning rabbits aged 35 days were randomly divided into two equal groups. Group I was fed a basal diet, while Group II was fed a basal diet supplemented with CSB (500 mg/kg). The experiment lasted for 40 days. The results showed that:CSB can improve the average daily feed intake (ADFI) and the middle and later feed conversion ratios, although the between-group differences were not significant (P> 0.05); CSB also improved the average daily gain (ADG), which of 14-35d and 1-35d showed significant differences (P< 0.05). CSB also improved the activity and amount of intestinal digestive enzymes. The duodenal and jejunal lipase activities and ileal amylase activity were significantly higher in Group II than Group I (P< 0.05). In addition, Group II had significantly higher amounts of duodenal and jejunal trypsin than Group I (P< 0.05). We also found that CSB improved the lengths of small intestinal villi and the depths of lower jejunum crypts, although the between-group differences were not significant (P> 0.05). Additionally, CSB significantly increased the jejunal and ileal V/C values (P< 0.05) and reduced jejunal and ileal cytokine levels. Specifically, it significantly reduced the levels of IFN-y in the jejunum and ileum and those of TNF-a and IL-6 in the ileum (P< 0.05). Dietary CSB increased the relative abundance of Firmicutes, Verrucomicrobia, Bacteroidaceae, Bacteroides, Verrucomicrobiaceae, Akkermansia, Clostridiaceae, and Clostridium,and reduced the relative abundance of Cyanobacteria, Acidobacteria, Ruminococcaceae, Oxalobacteraceae, Ruminococcus, Coprococcus. CSB improved total serum protein and serum albumin levels and significantly increased the levels of triglycerides (P< 0.05). CSB also improved the activity of serum superoxide dismutase, and lowered serum diamine oxidase activity,and significantly reduced serum malondialdehyde concentrations (P< 0.05).Experiment two:We studied the effects of CSB on rabbit coccidiosis. Eighty healthy, weaning rabbits aged 35 days were randomly divided into five equal groups. The rabbits were fed three diet types for 40 days:Groups I and III were fed a basal diet. Groups II and IV were fed a basal diet supplemented with CSB (500 mg/kg). Group V was fed a basal diet supplemented with toltrazuril (40 mg/kg). After 27 days, the rabbits in Groups HI, IV, and V were orally vaccinated with 5×105 sporulated oocysts of Eimeria magna. The results showed that:CSB improved the ADG during coccidia infection, the difference was not statistically significant (P> 0.05). CBS reduced OPG on the 9th and 10th days after oral challenge and, on the 10th day, Groups IV and V had significantly lower OPGs than Group III (P< 0.05). CBS improved the height of the small intestinal villi; this parameter was significantly higher in Groups II (compared with Group I), IV, and V (compared with Group Ⅲ) (P < 0.05). It also improved intestinal V/C values; the jejunal and ileal values were significantly higher in Group II than Group I (P< 0.05) and the duodenal, jejunal, and ileal V/C values of Group IV were significantly higher than those of Group III (P< 0.05). Intestinal cytokine levels were reduced by CBS in the control group:the jejunal and ileal IFN-y levels in Group II were significantly lower than those in Group I. The addition of CBS improved the cytokine levels in the challenged group. The jejunal and ileal IFN-y levels and jejunal IL-2 levels were significantly higher in Group IV than in Group III (P< 0.05). CBS also improved the levels of serum sCD4 and sCD8 molecules:Groups IV and V had significantly higher levels of serum sCD4 molecules than Group I (P<0.05). CBS improved the spleen index, although the between-group differences were not significant (P> 0.05). However, it significantly increased the thymus index in Groups II and V than in Group I and III (P< 0.05).Collectively, the results showed that supplementing rabbit feed with CSB increases growth performance, improves intestinal morphology, reduces the levels of intestinal inflammation factors, improves the composition of intestinal flora, and promotes overall intestinal health. Moreover, CSB improved the ADG, reduced oocyst discharge, improved intestinal injury, increased the level of cellular immunity, and improved resistance to coccidiosis in rabbits.