Abstract:
Housing conditions for laboratory animals can be improved by ensuring that animals are given an opportunity to perform species-specific behaviour. However, in most institutions space is a limiting factor because housing systems have been designed based on economic and ergonomic aspects without considering environmental needs of animals used in research. Vervet monkeys (Chlorocebus pygerythrus) are one common non-human primate species used in biomedical research. Despite the extensive use of vervets in research there is paucity of data describing the environmental enrichment of this species.
The current study sought to ascertain the compatibility between domestic cats and vervet monkeys, to allow for better utilisation of limited laboratory space. The idea was based on the cohabitation and stress alleviation effect of horses housed with goats. The study used a habituation method whereby the domestic cats were slowly introduced to the vervet monkeys. Domestic cats were selected as they were already housed within the same research centre, under semi-controlled conditions.
While the aim of the experiment was to ascertain the compatibility of cohousing cats with vervets, the possibility of the animals responding adversely to the interaction could not be overruled and hence common methods for monitoring stress in animals were used, which were behavioural changes, changes in faecal glucocorticoid metabolite concentrations and weight changes over time, to evaluate the situation. Faecal samples were collected for six days prior to introduction of domestic cats as baseline. After introducing the domestic cats, faeces were collected for another six days and the concentrations of faecal glucocorticoid metabolites (fGCM) determined using enzyme immunoassays. Behavioural observations were analysed to check for significant changes before and during cohousing using the Kruskal-Wallis One Way Analysis of Variance on Ranks and multiple comparisons using Tukey post hoc test. The paired sample t-test was used to compare alterations in weight and fGCM before and during cohousing.
On the first day of cohousing, the animals while inquisitive kept their distance. The vervets housed in cages that were closest to the domestic cats were the most active. During the first one minute, the vervets looked at the cats, climbed up to the top of the cage and made alarm calls. During the same time, the cats were moving and sniffing around the new housing. Overall average fGCM levels before cohousing was 0.24 ?g/g DW for the cats and 95.22 ng/g DW for the vervets while during cohousing the average was 0.34 ?g/g DW for the cats and 125.77 ng/g DW for the vervets. For both species, the fGCM levels were elevated a day after introduction, thereafter the levels started to decline.
The results from this study provides evidence that vervets and domestic cats can be cohoused without inducing prolonged additional stress and this can be used as a way of utilising limited laboratory animal space.
