Does captivity predispose felids to metabolic syndrome?
The captivity of wild animals is a practice implemented for a number of reasons, but primarily for the protection and conservation of endangered species. Due to limited resources and often a lack of knowledge, these animals are frequently fed the incorrect diets, and secured in enclosures which fail to simulate their natural environments. The dietary needs of felids are not yet well understood and may predispose these animals to metabolic diseases.
In a group of captive lions in the North West Province in South Africa, body weight was found to be highly skewed as the lions were greatly overweight. Furthermore, as a result of routine feeding, the need for behavioural activities of hunting and chasing prey have been removed, causing these lions to become inactive and rather lethargic.
There are various other felid species, such as caracals, cheetahs, leopards and lynxes, that reside in captivity. Each of these species differ in their biochemical and genetic makeup. They therefore may have different nutritional needs which is essential for their health.
It is well known that physical inactivity and obesity in humans are very clear risk factors for the onset of insulin resistance and type II diabetes, but also other diseases such as cardiovascular disease. These diseases have been observed in various zoo animals that lead a sedentary lifestyle. Considering the overweight lions which are showing signs of reduced physical activity, it is then not surprising that the question “Are these captive felids becoming insulin resistant?” is one of relevance.
What are we doing?
To answer this question, the MyoLab is investigating the muscle metabolism of various obese captive wild animals using mitochondrial respiration, in addition to the activity of several enzymes involved in the various phases of the metabolic pathway. Furthermore, specific proteins involved in insulin signalling pathways, are quantitatively determined. It is of great interest whether this change in lifestyle (i.e. captivity) has had an effect on both the structural composition of muscle and mitochondrial efficiency. Finally, the further understanding gathered on the mechanisms of insulin resistance and the progression to diabetes in the wild animal model may offer a window into the pathophysiology of this disease in the human.
★ Adrian Tordiffe (University of Pretoria)
★ Jørgen Jensen (Norwegian School of Sports Sciences)
★ Niels Ørtenblad (University of South Denmark, Denmark)
Past students on this project
★ James Peart (Honours, 2014)
★ Samantha Knobel (Honours, 2016)
★ Daneil Feldmann (MSc 2017, University of Cape Town)