The objective of the present study was to evaluate whether access to a running wheel increases voluntary physical activity in adult female and male domestic cats. Eight neutered domestic shorthair male cats (mean age 8·6 (sd 0·05) years) and eleven intact domestic shorthair female cats (mean age 3·3 (sd 0·14) years) were group housed for 22 h daily and individually housed during the feeding period. Voluntary physical activity was measured using accelerometers. Experimental design consisted of 1 week of baseline physical activity measurement, followed by 3 weeks of wheel habituation, and 1 week of physical activity measurement post-wheel habituation. Female cat voluntary physical activity levels increased (P < 0·05) post-habituation during the dark period, resulting in an altered (P < 0·05) light:dark activity ratio, whereas male cat voluntary physical activity levels remained unchanged post-habituation. Food anticipatory activity did not differ pre- and post-habituation. However, it corresponded to a numerically greater proportion of daily physical activity for males (17·5 %) v. females (12 %). In general, female cats were more active than male cats. Habituation to a running wheel appears to be an effective method to increase voluntary physical activity of younger female cats. Thus, running wheels might be a potential strategy in the prevention or management of feline obesity.

Milk proteins are the main components of everyday feeding and demonstrate a promising potential to change the mental condition. However, the effects of milk proteins after prolonged use remain poorly understood. The aim of the present study was to compare the effects of two whey proteins (α-lactalbumin (α-lac) and native whey) with casein on social and individual behaviour in mice. During a 30 d-long dietary intervention, male C57BL/6J mice had ad libitum access to an experimental diet containing 17 % (w/w) of one of three protein sources: α-lac, native whey or casein. Mice had voluntary access to a running wheel. Social behaviour (group and resident–intruder activity) was tested at baseline and at the end of the intervention. Half of each dietary group was then withdrawn from the diet and running wheel for 7 d, and social activity and individual behaviour tests (open field, elevated-plus maze, light–dark box and forced swimming) were performed, to evaluate anxiety and depression-like status. The study shows that the long-term ingestion of whey proteins may modulate behaviour when compared with casein. Diet enriched with α-lac exhibited anxiolytic and antidepressive activities while the whey diet improved sociability. The differences between the diet groups were pronounced under the running wheel and the withdrawal of the experimental diet, suggesting that the beneficial effects of the milk proteins are clearer in stressful situations. Diet-induced behavioural changes remained visible for a week after feeding, which suggests that the proteins of the milk whey fraction have prolonged efficacy on the mental state of mice.