Digestive utilization of ozone-exposed forage by rabbits (Oryctolagus cuniculus)

A mixture of common Southern Piedmont (USA) grassland species (Lolium arundinacea, Paspalum dilatatum, Cynodon dactylon and Trifolium repens) was exposed to O3 [ambient (non-filtered; NF) and twice-ambient (2X) concentrations] and fed to individually caged New Zealand white rabbits (Oryctolagus cuniculus) in a digestibility experiment. Forages and feed refusals were analyzed for concentrations of total cell wall constituents, lignin, crude protein, and soluble and hydrolyzable phenolic fractions. Neutral detergent fiber and acid detergent fiber digestibility by rabbits were significantly lower for 2X than NF forage. Decreased digestibility could not be attributed to lignin concentrations, but was associated with increased concentrations of acid-hydrolyzable and saponifiable phenolics. Exposure of forage to elevated O3 resulted in decreased digestible dry matter intake by rabbits. Elevated O3 concentrations could be expected to have a negative impact on forage quality, resulting in decreased nutrient utilization by mammalian herbivores in Southern Piedmont grasslands under projected future climate scenarios. - Highlights: ► Exposure of forage to elevated O3 resulted in decreased digestibility by rabbits. ► Elevated O3 could be expected to have negative impacts on forage quality. ► This study is believed to be the first of its kind. ► A mechanism of action of decreased intake/digestion in animal herbivores is proposed. - O3 affects forage digestibility in a model non-ruminant mammalian herbivore (rabbit).