Rumen protected riboflavin and rumen protected pantothenate improved growth performance, nutrient digestion and rumen fermentation in Angus bulls

The study evaluated the effects of rumen protected riboflavin (RPRF) and rumen protected pantothenate (RPPA) on growth performance, nutrient digestibility, rumen fermentation and blood metabolites in bulls. Forty Angus bulls were blocked by body weight and randomly assigned to four treatments in a 2 × 2 factorial design, with factors being 0 or 60 mg riboflavin/kg DM from RPRF and 0 or 35 mg pantothenate/kg DM from RPPA. The experimental period was 80 days, with 20 days for adaptation and 60 days for sample collection. Average daily gain increased and feed conversion ratio decreased, and the changes were greater for supplementing RPPA in diets with RPRF than in diets without RPRF. The populations of total protozoa and Ruminococcus albus increased, but the increases were smaller for supplementing RPPA in diets with RPRF than in diets without RPRF. The total-tract digestibility of dry matter, organic matter, crude protein and neutral detergent fibre increased with RPRF or RPPA addition. The digestibility of acid detergent fibre increased with RPPA addition, and digestibility of non-fibre carbohydrate increased with RPRF addition. The rumen pH and ammonia-N concentration decreased, but total volatile fatty acids concentration and acetate to propionate ratio increased with RPRF or RPPA supplementation. The activities of xylanase and pectinase and populations of total bacteria, R. flavefaciens and Prevotella ruminicola increased with RPRF or RPPA supplementation. The populations of total fungi and Fibrobacter succinogenes increased with RPRF addition, and the activities of α-amylase and protease increased with RPPA addition. The data suggested that RPRF or/and RPPA supply improved growth performance of bulls, and the effect seemed to be due mostly to the vitamins released in the rumen.