Nutrient Digestibility in Zoo-Kept Tapirs (Tapirus spp) as Compared to Other Herbivores.

Tapirs are hindgut fermenters with a natural diet dominated by browse, with a certain proportion of wild fruit. By contrast, diets fed to tapirs in zoos are often dominated by domestic fruit and other sources of easily digestible carbohydrates, which have been linked to obesity and various health problems. We aimed at better understanding the digestive physiology of tapirs, measuring the digestive efficiency of 13 lowland (Tapirus terrestris) and five Malayan (Tapirus indicus) tapirs from five zoos on various zoo diets by recording intake and total faecal excretion. Additionally, we aimed at evaluating zoo diets, by assessing relationships between dietary characteristics and data on intake and faeces consistency, and compared the data gained in the zoo study to those of faecal samples of free-ranging tapirs. Tapirs showed digestive principles reported in other herbivores, such as higher levels of metabolic faecal nitrogen and a lower intake on diets of higher digestibility, or a decrease in digestibility with increasing dietary fibre concentrations. Compared to horses or grazing rhinoceroses, organic matter digestibility in tapirs was more negatively affected by dietary fibre; additionally, tapirs had comparatively low fibre digestibility. This is possibly linked to their comparatively poor chewing efficacy. The readiness to ingest a hay-only diet was directly proportional to the amount of hay in the usual zoo diet, supporting reports that it may be difficult to achieve high hay intakes in tapirs instantaneously. Faeces consistency was closer to the natural condition with higher proportions of roughage in the diet. Compared to a set of faecal samples from the wild, zoo faeces were generally lower in fibre. This study supports previous suggestions that zoo tapirs could benefit, in terms of mimicking their digestive physiology and feeding behaviour in natural habitats, from diets based on a readily ingested roughage source, especially from browse.