Interpretive Summary: Digestibility of diets containing calcium salts of fatty acids or soybean oil in horses
By: Anne Wallace
Performance horses have an increased need for food energy than they can reasonably obtain from grazing. The addition of dietary concentrates to pelleted feed is therefore necessary to meet their daily energy requirements. Added fat increases the energy in pelleted feed, however, it also generates additional challenges in digestibility, palpability and pellet durability.
In this Translational Animal Science study (April 2020), researchers looked at calcium salts of fatty acids (CSFAs) as a potential dietary concentrate to add to pelleted horse feed. Commonly fed to ruminants, CFSAs are not well studied in horses. The goal was to determine the digestibility of CSFA in horses compared to soybean oil (SB).
Eight horses were fed pelleted concentrate with CSFA or SB oil. The apparent total tract digestibility (ATTD) of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), crude fat (CF), and gross energy (GE) were measured. Fecal contents were collected from the cecum (through a cannula port) and volatile fatty acids (VFA) and long chain fatty acid (LCFA) concentration were measured. Blood was also drawn to test for triglycerides and cholesterol.
Results found no differences in the ATTD of horses fed CSFA compared to horses fed the SB concentrate. There were also no significant differences in blood values for triglycerides and cholesterol. However, VFAs were increased in horses fed SB over CSFAs and LCFAs were increased in horses fed CSFAs over SBs, but only at a specific time point in the gut fermentation process (2 hours after feeding).
Overall, the results of this study suggest no significant differences in the digestibility of CSFA compared to SB in pelleted horse feed. The slight differences in fatty acid concentration during cecal fermentation are of unknown significance and may be an area of interest to elaborate on in future studies.