Multi-criteria study on a change to a fruit-free diet in Cebidae and Cercopithecidae

Nutrient intake of captive primates does not necessarily reflect that of their wild counterparts. Diets in captivity are often higher in non-structural carbohydrates and lower in fibre, resulting in health issues such as obesity, dental issues, diarrhoea and behavioural problems. The main objective of this study was to establish and monitor a change to a fruit-free diet in five species of primates (Ateles fusciceps rufiventris, Cercopithecus hamlyni, Allochrocebus lhoesti, Cercopithecus roloway, Sapajus xanthosternos). Nutrition and ethology was monitored, including an assessment of the nutritional composition of diets before, during and after diet change; monitoring of faeces consistency; observation of feeding choices; and the occurrence of aggressive behaviour and vocalisations by scan sampling. The initial diet included cultivated fruits and vegetables and some extras (cereals, animal and vegetable proteins) and was higher in non-structural carbohydrates, in particular sugar, than recommended in husbandry guidelines. After a diet change of four weeks during which fruits were gradually removed, a decrease of mean sugar content by more than half and an increase in fibre was achieved. Improved faeces consistency was observed for spider monkeys A. f. rufiventris and Hamlyn monkeys C. hamlyni (change in Bristol stool score: 6 to 4 and 7 to 3, respectively). An increase in time spent feeding was observed for capuchins S. xanthosternos and Hamlyn monkeys (1.5 to 2 times longer). These findings underline the beneficial effects of changing to fruit-free high-fibre diets in zoo-managed primates.