Effect of Starch Source in Pelleted Concentrates on Fecal Bacteria in Prepartum and Postpartum Mares.

The research investigates how the starch source in horse feed affects the composition of bacteria in horse feces, both before and after giving birth. The researchers found that the type of starch did not significantly affect the bacterial communities in horse feces but the act of giving birth did.

Research Goals and Methods

• The researchers aimed to study how the source of starch in horse food, either oat-based or corn and wheat middlings-based, could influence the fecal bacteria communities in broodmares (mares used for breeding).
• This study used 18 Thoroughbred mares which were paired by their last breeding date and then randomly assigned to one of two diets. They were either given an oat-based or a corn and wheat middlings-based pelleted concentrate with forage.
• Feeding of the assigned diet started on the 310th day of the mares’ gestation period. Fecal samples from the mares were collected on five occasions: the 324th day of gestation, before giving birth, the day after giving birth, two weeks after giving birth, and four weeks after giving birth.
• The collected fecal samples were then examined for the presence of Lactobacillus spp., amylolytic bacteria, and cellulolytic bacteria. These bacteria groups were chosen because they feed on starch and are an important part of the horse’s gut microbiota, helping to digest food.

Results

• The source of starch in the horse feed did not have a significant effect on the bacterial communities found in the horse feces. This suggests that the processing of the concentrate into pellets could have lessened some of the anticipated effects the starch source would have on the horse’s gut bacteria.
• The bacterial community did not change significantly over time for amylolytic bacteria. However, the numbers of lactobacilli and cellulolytic bacteria were lower the day after the mares gave birth, implying that the act of giving birth can impact the horse’s gut microbiota.

Implications

• This research indicates that the source of starch in a horse’s diet does not significantly influence the composition of bacterial communities in a horse’s gut. This has implications for the formulation of horse feed, and how much attention needs to be given to the source of starch.
• However, the fact that giving birth was associated with changes in the horses’ gut microbiota suggests that additional consideration may need to be given to the diet and care of broodmares around the time of giving birth.