Effect of Donor Diet on In Vitro Digestibility of Forages by Fecal Inoculate.

This research paper investigates how the diet of horse fecal donors can impact the in vitro dry matter digestibility of different forages. The study found that the type of diet, whether it’s high in starch or fiber, can affect the ability of the fecal microbiome to digest neutral detergent fiber, which is a significant parameter when testing equine fecal samples for in vitro digestion procedures.

Objective and Importance of Study

• The main objective of the study was to uncover the influence of the fecal donor’s diet on in vitro dry matter digestibility (DMD) of forages. This is important because fecal donors are instrumental in in vitro digestion tests, and their diet can influence the accuracy of these tests.
• The research is critical because it provides insights into how diet can impact the gut microbiome and subsequently, the ability to digest neutral detergent fiber – an essential component in forage that needs to be digested by horses.

Research Methodology

• Six Quarter Horses were used for this study, and the research was conducted using a crossover design. This means that each horse was fed both diet types (one high in starch and the other high in fiber), but in different periods.
• The horses produced fecal samples on the 22nd day of each feeding period, and the samples were used to inoculate in vitro fermentation vessels. This process allowed the researchers to analyze the impact of the donor diet on DMD, neutral detergent fiber digestibility (NDFD), and acid detergent fiber digestibility (ADFD) of four different types of forages.
• The data was analyzed using the MIXED procedure of SAS to evaluate the digestibility differences influenced by diet and forage composition interaction. The MIXED procedure is a statistical analysis method that is capable of handling complex experimental designs.

Key Findings

• The study found that fecal samples from horses fed a grain diet promoted higher NDFD of forages with high neutral detergent fiber (NDF) and low crude protein (CP) when CP and NDF were used as covariates.
• The study discovered a “horse effect” on DMD and NDFD, suggesting that the individual horse’s characteristics can independently influence DMD and NDFD.
• Overall, the study concluded that the diet can possibly influence the horse’s hindgut microbiome’s capacity to digest neutral detergent fiber. Therefore, this factor should be considered when selecting equine fecal samples for in vitro digestion procedures.