Experience with a variety of feed colours reduces feed neophobia in the turkey
Résumé
When exposed to a new feed, farm birds are commonly reluctant to eat this feed. This phenomenon, called feed neophobia, could be reduced by exposing young animals to a variety of novel feeds. We investigated whether previous experience with a variety of feed colours could reduce food neophobia in turkeys. We hypothesised that both greater variety in visual experience and frequency of changes would increase the acceptance of novel feeds. To test this hypothesis, hatchling turkeys were exposed to a 28-day feeding regime differing in feed colours and frequency of feeding transitions. There were 3 experimental groups: one group was exposed to only one colour of feed (C0 group); the second group was exposed to green and red feeds on alternate weeks (low change rate: LC group) and the third group was exposed to green and red feeds changed randomly each day (high change rate: HC). As the contrast between the novel colour and the familiar feed could also influence bird responses, two subgroups were constituted within each experimental group: one receiving green feed and the other red feed before the novel feed test (i.e. C0 red, C0 green; LC red, LC green; HC red, HC green). From D29 to D31, all birds were exposed to blue, light-green or white novel feeds for 5 min each. Short-term feed intake (5 min) was measured the day before change-over and at each change-over on the three subsequent test-days. All groups were found to eat less of the novel feed than the familiar feed but this difference varied according to the 28-day feeding regime and the feed received immediately prior to testing, suggesting a colour contrast effect. The effect of visual experience with a variety of feed colours on neophobia was observed only when there was a marked contrast of colour with the feed received prior to testing which could be explained by an effect of memory on discrimination. When birds had been exposed to LC schedules, this visual experience resulted in the most significant decrease in neophobia. We conclude that changes in diet colour induce various levels of neophobia in turkeys which depend on the visual contrast between the new diet and that of the previous day, and the alternation rate of the visual experience. These results suggest that in production systems, the use of early visual experience with a variety of feed colours could reduce neophobia problems during change-over.