Effects of High Starch and Sugar Diets on Postprandial Inflammatory Proteins in Horses

Monday, July 21, 2014: 2:00 PM
3501F (Kansas City Convention Center)
Jessica K. Suagee , Ohio State, Wooster, OH
Rebecca K. Splan , Virginia Tech, Middleburg, VA
Kelcey L. Swyers , Ranch-Way Feeds, Fort Collins, CO
Raymond J Geor , Michigan State University, East Lansing, MI
Benjamin A. Corl , Virginia Tech, Blacksburg, VA
Abstract Text:

Diets high in starches and sugars (HS) are linked to metabolic disorders in horses. Further, overconsumption of starch can result in digestive disturbances and laminitis. We hypothesize that high starch intake reduces intestinal pH and thus the integrity of the epithelial tight junctions, enabling lipopolysaccharide (LPS) to cross into the blood stream. For this experiment, plasma samples were obtained from mares (n=6) consuming a diet high (HS) low (LS) in starch and sugar (Table 1). Horses consumed 20% of their DE requirement as concentrate and 80% as mixed grass/legume hay (Table 1). Concentrate was offered individually in two equal feedings (0800 and 1400 hr) while hay was group fed in two equal feedings following concentrate consumption. Samples were collected on d1 and on d90 at 0, 1, 2, 3, and 4 hr post-consumption of the assigned diet (0800 feeding), as part of a larger study that investigated post- prandial starch responses. Plasma samples were then analyzed for LPS, tumor necrosis factor-α (TNF), interleukin (IL)-6, and IL1β. LPS was analyzed using a commercial colorimetric assay, TNF and IL1β were analyzed using commercial ELISAs, and IL6 was analyzed using individual antibodies and a previously validated method.  Each plasma factor was analyzed using repeated measures (SAS v. 9.3) for fixed effects and interactions of hour, day, and diet, with hour 0 values as a covariate. LPS concentrations were lower in HS horses on d90 than on d1 (P < 0.02) but were otherwise unchanged. IL1β concentrations increased in HS horses 1 hr post-feeding compared to LS horses (P < 0.03), without any differences between diets at other hours (P > 0.55). IL6 concentrations were influenced by hour (P < 0.01) but not diet (P > 0.78), whereby all horses had elevated IL6 concentrations 1 hr post-feeding compared to hour 0 (P < 0.01). TNF tended to be higher in HS horses than LS horses (P = 0.07) but was not influenced by day of study or hour post feeding (P > 0.51). Consuming a high starch and sugar diet briefly elevates plasma IL1β, but this is most likely not due to elevated LPS concentrations. Of further interest was the finding that all horses, regardless of diet, had elevated postprandial IL6 concentrations.


Table 1. Diet composition

Nutrient, %DM basis




Water soluble carbohydrates








Keywords: interleukin-1β, high-starch diet, horse, inflammation