Implementing a low‐starch biscuit‐free diet in zoo gorillas: The impact on health

Abstract

In the wild, western lowland gorillas consume a diet high in fiber and low in caloric density. In contrast, many gorillas in zoos consume a diet that is high-calorie and low in fiber. Some items commonly used in captive gorilla diets contain high levels of starch and sugars, which are minimal in the natural diet of gorillas. There is a growing concern that captive gorillas may qualify as obese. Furthermore, the leading cause of death for adult male gorillas in zoos is heart disease. In humans, a diet that is high in simple carbohydrates is associated with both obesity and the incidence of heart disease. In response to these issues, we implemented a biscuit-free diet (free of biscuits and low in fruit) and measured serum biomarkers of obesity and insulin resistance pre- and post-diet change at three institutions: North Carolina Zoological Garden, Cleveland Metroparks Zoo, and Columbus Zoo and Aquarium. We also added a resistant starch supplement to gorilla diets at two of the above institutions. We anticipated that these diet changes would positively affect biomarkers of obesity and insulin resistance. Both diet manipulations led to a reduction in insulin. Resistant starch also decreased overall serum cholesterol levels. Future research will examine these health changes in a greater number of individuals to determine if the results remain consistent with these preliminary findings.

Behavioral and hormonal responses to the availability of forage material in Western lowland gorillas (Gorilla gorilla gorilla)

“…Cardiac disease is the primary source of mortality for adult male gorillas in captivity (Meehan & Lowenstine, ; Murphy, Dennis, Devlin, Meehan, & Kutinsky, ), and the majority of captive animals are likely obese (Less, ). The biscuit‐free diet did not reduce inactivity as expected, but the diet modification did positively change serum biomarkers related to obesity, lowering insulin and, when gorillas also were fed resistant starch, cholesterol (Less, Lukas, et al, ). Although there is more to learn about the etiology of cardiac disease in captive gorillas, preliminary evidence, as well as parallels to human health, suggest that diet composition and presentation are likely contributors to this epidemic.…”

Commentary: is Alzheimer's disease uniquely human?

“…Herbivorous species such as gorillas pose special problems because we do not know which micronutrients are obtained from diets that include various parts of more than 100 species of plants. Moreover, gorillas, like other apes tend to become obese in captivity (Less et al, 2014). Clinical grade elevation of blood cholesterol is common in captive great apes on a wide range of diets (reviewed in Finch and Stanford, 2004, Table 3A).…”

“…The relationship of various heart conditions to conditions of captivity is poorly understood. Recent interventions to reduce gorilla obesity in zoos with a low-starch diet showed benefits to insulin regulation even in the short term (Less et al, 2014). We anticipate continued increase in the longevity of captive species as husbandry becomes more refined.…”

Trialling nutrient recommendations for slow lorises (Nycticebus spp.) based on wild feeding ecology

“…Both of these artificial groups involve many species which are distantly related and have very different physiologies, behaviour and ecology. The OWM group in particular has a large variety of primate taxa which have been shown to not fit the OWM model, such as Lemuridae (Dierenfeld & McCann, ; Donadeo, Kerr, Morris, & Swanson, ; Junge, Williams, & Campbell, ), Colobinae (Nijboer & Dierenfeld, ), Hominidae (Crissey et al., ; Hoffer, ; Less et al., ) and Lorisidae (Williams, Cabana, & Nekaris, ). There is evidence that the majority of taxa require their own unique nutritional requirements and using a “one model approach” may not be appropriate (NRC, ).…”