In vitro and in vivo rumen protection of proteins coated with calcium soaps of long-chain fatty acids

Abstract

SummaryThe in sacco, in vitro and in vivo effects of feeding proteins partially coated with calcium soaps of longchain fatty acids were examined.In sacco, 84–90% of whey powder and soya-bean meal coated with calcium salts of fatty acids remained after 20 h incubation in the rumen of sheep. In vitro tests revealed no effects on volatile fatty acid or ammonia production.In vivo sheep balance studies, where soya-bean meal coated with calcium soaps was substituted for soya-bean meal, showed no effects on ammonia or volatile fatty acid production in the rumen due to the calcium soap coated proteins. No changes were observed in digestibilities of dry matter, nitrogen or acid detergent fibre; total fatty acid digestion increased. Nitrogen balance was improved slightly in sheep fed the protected protein.It appears that proteins coated with calcium soaps are not degraded in the rumen and thus energy and non-degradable protein can be supplied to ruminants by this route.