Starch in horse diet improves feces microbiota, in vitro digestibility of fiber and dry matter

When higher concentrations of starch are given to horses, starch degradation may shift from small intestine further to hindgut where it can cause alternation of the hindgut microbiome and unsatisfied fiber fermentation. The aim of the study was to determine the effect of the daily starch intake levels of 0.3, 0.6 and 0.9 g/kg body weight (BW) of the animal on the fecal in vitro digestibility of neutral detergent fibers (IVNDFD) and dry matter (IVDMD) and whether changes in fecal microbiome occur. Three horses were fed in three periods with three starch levels in the trial, designed as 3x3 latin square. The main influences were the level of starch in the horse meal and the effect of an individual animal on in vitro digestibility of three forages (straw, clover and meadow hay). The results showed that with increasing starch level, proportionally the significant increase in IVNDFD and IVDMD in all forages was observed. By increasing the starch level, the higher number of lactobacilli, amylolytic and cellulolytic bacteria in the feces of the horse was recorded. It can be concluded that the daily level of starch in the horse meal up to 0.9 g/kg BW has a positive effect on fiber digestibility and feces microbiome.