Effect of administration of an anaerobic gut fungus isolated from wild blue bull (Boselaphus tragocamelus) to buffaloes (Bubalus bubalis) on in vivo ruminal fermentation and digestion of nutrients

Experiments were conducted to evaluate the effect of administration of an elite strain of anaerobic fungi (Piromyces strain FNG5; isolated from the faeces of wild herbivore, blue bull) on nutrient digestion, ruminal fermentation characteristics, microbial populations, enzyme profile and N retention in buffaloes. In experiment 1, eight growing buffaloes with body weight range of 237–271 kg receiving wheat straw and concentrate mixture in equal proportions were randomly assigned to two dietary treatments with four buffaloes in each group. Control group buffaloes were fed 200 ml of autoclaved fungal medium whereas the treatment group was fed 200 ml of the anaerobic fungal culture daily by mixing the fungal culture/medium with the concentrate mixture. After 26 day of feeding, a metabolism trial of 6 day duration was conducted to study total tract nutrient digestibility and N balance. In experiment 2, eight rumen fistulated growing buffaloes with body weight range of 253–298 kg receiving wheat straw and concentrate mixture in 50:50 ratio were randomly assigned to two dietary treatments with four buffaloes in each group. Control and treatment buffaloes were administered 200 ml of autoclaved fungal medium and 200 ml of the anaerobic fungal culture, respectively daily through rumen fistula. Buffaloes were exposed to each treatment for 21 day before sampling of rumen fluid and rumen contents began. Feeding of the fungal strain resulted in increase in total tract digestibility of dry matter (DM), OM, NDF and acid detergent fiber (ADF), but no change in digestibilities of crude protein or ether extract. N retention, expressed either relative to N intake or to N absorbed was higher in the fungus fed group. On intraruminal dosing of the fungal isolate, concentrations of VFA increased substantially (9.17 mM/100 ml versus to 14.5 mM/100 ml). There was also an increase in cellulolytic (2.5 fold), hemicellulolytic (2.9 fold) and total bacterial counts (2.5 fold) and fungal count (4.4 fold) on administration of the fungus. Activities of carboxymethyl cellulase, xylanase, microcrystalline cellulase, acetyl esterase, feruloyl esterase and protease of rumen content also increased. In situ disappearance of DM, NDF and ADF at 72 h of incubation increased with administration of the fungal culture. In vitro DM degradability of wheat straw by ruminal microflora of fungus fed buffaloes was higher than that of control buffaloes at 48 h of fermentation. Administration of a fungal isolate with superior lignocellulolytic activity isolated from faeces of a wild ruminant can improve nutrient utilization in buffaloes.