Dietary supplementation of free or two fat-coated sodium butyrate with varying release times on gastrointestinal development and tight junctions in preweaning Holstein calves

The aim of this study was to determine the effects of free and two fat-coated sodium butyrate (SB) on performance, diarrhea incidence, gastrointestinal tract (GIT) development, tight junctions (TJ), and adherens junctions in preweaning calves. Forty male calves were divided into four treatment groups: control starter (CON), control starter supplemented with free SB (USB), rapid release SB (RSB), and slow-release SB (SSB) at a SB addition level of 3.0 g/kg (as-fed basis) in a high starch starter (380 g/kg). The calves were fed calf starter for 9 weeks and then the GIT of four calves from each group was harvested. There was no difference in the growth performance and feed efficiency under SB treatments (P > 0.05), although RSB decreased starter intake for the entire period as compared to the CON and USB (P < 0.05). Diarrhea rates and frequencies were lower with the USB and RSB treatments as compared with CON (P < 0.05). The weight and papillae surface area of the rumen in USB were higher than the CON, RSB, and SSB (P < 0.05), although RSB increased the mucosa thickness of the abomasum as compared to the other three groups (P < 0.05). The mucosa thickness of the duodenum in SSB was thicker than USB and RSB (P < 0.05). The villous height and villus height:crypt depth ratio of the ileum was higher in USB than the CON, RSB, and SSB (P < 0.05). Muscularis thickness of the cecum was higher in USB than the RSB and SSB (P < 0.05), and the parameter of the colon was higher in RSB than SSB (P < 0.05). Claudin-1 was increased in the rumen by USB (P < 0.05) and claudin-1 was increased by RSB, and occludin and zonula occludens protein-1 were increased by USB and SSB in the jejunum (P < 0.05). However, occludin was decreased by SSB, and zonula occludens protein-1 was impaired by both RSB and SSB in the colon (P < 0.05). SB treatments had no effect (P > 0.05) on the expression of e-cadherin and beta-catenin in the GIT. The incidence of diarrhea was negatively correlated with the protein expression of claudin-1 (P < 0.05) within the jejunum. In conclusion, USB showed more benefits than the RSB and SSB in high starch starter on the diarrhea incidence, GIT development, and TJ in calves, and diarrhea incidence was associated with claudin-1 expression in the jejunum.