Effects of Phenolic Compounds in Cell Walls of Orange and Artichoke By-Product Silages on In vitro Digestibility

Abstract

Megías, M.D., Cherney, J.H. and Cherney, D.J.R. 1997. Effects of phenolic compounds in cell walls of orange and artichoke by-product silages on in vitro digestibility. J. Appl. Anim. Res., 12: 127–136. By-products of the canning industry are extensively used as ruminant fodder in some areas of the world Characterization of the phenolic content of these feeds and their influence on digestibility is lacking. Phenolic carbohydrate complexes were isolated from cellulose extracts of neutral detergent fiber from orange pulp (Citrus aurantium L.) and artichoke (Cynara scolymus L.) pulp after 100 days ensiling. The effect of the byproduct phenolic compounds on fiber digestion of corn stover (0.25 g) was determined by the addition of extracts at levels equivalent to 0.5, 1.0 and 2.0 g of neutral detergent fiber. Fiber digestion was inhibited (P>0.05), but only at the 2.0 g rate. Fiber digestion at this rate was more inhibited by orange pulp (79.3±1.44%) than artichoke extracts (23.12±1.5%). Ferulic acid was the predominant phenolic acid present in orange pulp, while vanillic acid was the primary phenolic acid in artichoke pulp. Difference in inhibition of fiber digestion may have been due to differences in phenolic acids and/or to the larger peak eluted with the orange pulp, indicative of larger quantities of the phenolic-carbohydrate complex in artichoke. Because large quantities of the extracts were required to elicit an effect, it appears unlikely that the phenolic-carbohydrate complexes in these by-products would pose a problem in most ruminant feeding situations.