Black rhinoceros (Diceros bicornis) and domestic horse (Equus caballus) hindgut microflora demonstrate similar fermentation responses to grape seed extract supplementation in vitro.

The research explores the effects of grape seed extract (GSE) supplementation on the hindgut fermentation in domestic horses and black rhinoceroses, highlighting that both animals showed similar responses. The research proposes the equine nutrition model as a valid approach for analyzing potential supplements for rhinoceroses, although further studies are needed for the comparison of foregut digestibility and nutrient absorption between the two species.

Objective and Methodology

• The primary aim of this research was to examine the impact of grape seed extracts, a rich source of condensed tannins, on the hindgut fermentation in black rhinoceroses.
• The secondary aim was to validate the domestic horse model for assessing the impact on black rhinoceroses and comparing fermentation responses to GSE.
• The researchers used a continuous single-flow in vitro culture system for the experiments.
• Feces from horses and black rhinoceroses were used as inoculum sources. Four different diets with varying levels of GSE inclusion were tested.

Results and Findings

• The study found that increasing the inclusion of GSE stimulated microbial growth and fermentation, and increased the diet’s iron-binding capacity and CT concentration.
• It was also found that the hindgut microflora nutrient digestibility and fermentation responses to GSE in horse and black rhinoceros did not vary significantly.
• This result suggested the adequacy of equine fermentation as a model for microbial fermentation in black rhinoceroses.
• However, the research noted that these findings were limited to hindgut fermentation, suggesting the need for more research on foregut digestibility and nutrient absorption comparison between the two species.

Implications and Limitations

• Based on the study, the inclusion of GSE in black rhinoceros diets up to 4% is not likely to adversely affect hindgut nutrient digestibility, microbial viability, and fermentation.
• While the research offers significant insights, the study acknowledges the limitation of only focusing on hindgut fermentation. They emphasize the need for additional research on foregut digestibility and nutrient absorption for a more comprehensive understanding.