Impact of varied diets on some aspects of behaviour and physiology in laboratory mice

• Main Author: Maimaniee, T. A.
• Published: Swansea University 1999
• Subjects: 612.3
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637981

The impact of dietary fats was assessed in Swiss mice of differing ages (juvenile and adult) and sexes for two periods (3 and 6 weeks). Mice were fed four specially-formulated pelleted diets containing respectively 8% saturated vegetable fat, 8% soya oil, 8% olive oil and 2% soya oil (with identities hidden from the experimenter) or a local commercial chow. Subjects were individually housed in traditional cages or in metabolism cages to assess daily food consumption and body weight changes over the experimental period. Traditionally-caged mice were also assessed under red lighting for behaviour in a modified 'open field' (a 30 x 20 cm box with a black floor). Videotaped records were analysed using 'The Observer' system quantifying transitions between inner and outer areas, rearing, freezing, grooming and defaecation as well as location in the two equal-sized zones. Measures were factor analysed to facilitate interpretation. Other subjects were used to assess core body temperatures as well as a range of blood (cholesterol, triglycerides and glucose) and plasma (high density lipoprotein cholesterol) measures. Animals in metabolism cages were used to determine daily production of dried faecal material and urine in response to the diets. Clearly, these non-isocaloric diets differed in palatabilities, producing complex effects on growth as well as physiological and behavioural measures. Many indices were influenced by age, sex, duration of dietary exposure and the type of caging used. Interactions between factors were common. Defaecation does not seem to provide a useful index of 'emotionality' in this type of study. Investigations lacking a wide range of indices are unlikely to provide unequivocal support for postulated links between dietary lipids and behaviour. The thesis broadly supports the contention that dietary fats subtly influence mood in mice and differentially influence blood cholesterol values and other factors relevant to coronary heart disease risk in humans.