Effects of added chelated trace minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract in horses. Part I: Blood nutrient concentration and digestibility.

This study explored the effects of certain dietary additives, including chelated minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract, on nutrient digestibility in horses. The researchers concluded that these additives did not significantly impact nutrient digestibility.

Research Aim and Methodology

• The study aimed to determine if adding dietary supplements like chelated minerals, organic selenium (Se), yeast culture, direct-fed microbials, and Yucca schidigera extract would enhance nutrient digestibility in a horse’s diet.
• Horses of various ages, specifically Quarter Horse geldings aged from 4.5 to 16 years, with an average body weight of 522 kg ± 46 kg, were part of this study.
• The horses were adapted to all-pellet diets, which were created with and without the above-mentioned additives, followed by a 14-day collection period of their feces and urine for analysis.
• Replacement of sulfated forms of Copper (Cu), Zinc (Zn), Manganese (Mn) and Cobalt (Co) was done with chelated sources at a 100% replacement rate.

Study Results and Interpretation

• No notable differences were found in the apparent digestibility of dry matter (DM), acid detergent fiber (ADF), or neutral detergent fiber (NDF) between diet treatments.
• Similarly, the study found no observable difference in digestibility of Cu, Zn, Mn, Co, or Se with the inclusion of additives.
• The study also found no observable difference in the concentration levels of Cu, Mn, or Co in the horse’s serum between additive-containing (ADD) and control (CTRL) diets, both at adaptation or collection time points.
• However, an interesting finding was that the serum Zn levels were higher during the collection period for horses consuming the CTRL diet as compared to those consuming the ADD diet.
• The concentration of Se in the whole blood of CTRL horses was found to be higher than that of the ADD group, both at the initiation and end of the diet period.
• Over time, irrespective of diet, the Cu and Co concentration levels in the horses’ serum increased, whereas Se increased in the whole blood of horses in the CTRL group.
• The results indicate that the inclusion of these specific dietary additives did not have a significant effect on nutrient digestibility in horses maintained on these diets.