Effects of maturity and ensiling of Agave salmiana on nutritional quality for lambs

The objectives of this study were to evaluate the chemical composition, intake, N balance, total tract digestion and ruminal disappearance of dry matter (DM) and neutral detergent fiber (NDF) of Agave salmiana harvested when young or mature and fed either fresh or as silage to lambs. The experimental design was a 4 × 4 Latin square with a factorial (2 × 2) arrangement of treatments: (a) process = fresh or silage; (b) agave age = young (12 years) or mature (16 years and sterilized). Young agave had a higher organic matter (OM) and lower crude protein (CP) and saponin concentrations than mature. Ensiling decreased soluble carbohydrates (SC), saponin concentrations, and pH. Dry matter and OM intakes of agave fresh were lower than others. Saponin intake was lower with agave silage than fresh. Total tract digestion was not altered by treatments. The highest nitrogen retention value was found in lambs fed mature agave as silage. Both ruminal disappearance of the insoluble fraction and disappearance rate of DM and NDF for young were higher than for mature agave. Ruminal molar proportion of propionate was higher and acetate:propionate ratio was lower in lambs fed agave silage than fresh. Lambs fed young agave had lower ciliate protozoa numbers than those fed mature agave. Ensiling agave increased NDF disappearance, ruminal fermentation and N balance in lambs.