Studies on feed digestibilities in captive Asian elephants (Elephas maximus).

The research article explores the differences between the digestive systems of horses and Asian elephants, considering changes in feed, and the associated uptake of nutrients. It concludes that while there are some similarities between the two species, there are significant differences that potentially impact the health and wellbeing of elephants, especially in captive environments.

Objective of the Research

• The main aim of the research was to determine whether horses could be used as a nutritional model for Asian elephants. This was achieved by studying the digestibility of various food sources in elephants and comparing the results with known data about horses.

Methodology

• The researchers used six captive Asian elephants and monitored their digestive processes with six different dietary regimes, employing the double marker method. This method is widely accepted as a reliable way to monitor nutrient uptake and digestive efficiency.
• Two types of digestibility markers were used: internal (acid detergent lignin) and external (chromium oxide). These markers provided information about how effectively the elephants were able to obtain nutrients from different types of feed.

Findings

• Similar to horses, the elephants’ ability to digest food and absorb nutrients was influenced by dietary supplements and the crude fibre content of their diet.
• In terms of calcium absorption parameters and faecal volatile fatty acid composition, the elephants resembled horses.
• However, the cumulative digestibility coefficients for all nutrients were distinctly lower in the elephants because the rate at which they processed ingested food was faster.

Implications

• The research does not explain why, despite their immense body weight which theoretically would provide high digestive potential, elephants did not fully utilize this potential.
• The researchers found differences in the faecal volatile fatty acid concentrations between elephants in captivity and those living in the wild. This suggests that an elephant’s digestive process is substantially influenced by its diet and environmental conditions. It supports earlier findings indicating a heavy reliance of free-ranging elephants on browse forage.