Vitamin C supplementation and fear-reduction in Japanese quail: short-term cumulative effects

1. Fear-related behaviour was measured in individually-housed Japanese quail which had received either untreated drinking water (UDW) or a vitamin C solution (ascorbyl-2-polyphosphate, APP, 1 g L-ascorbic acid/1 for 1 or 4 d. Behavioural tests were carried out at 24 or 27 d of age. Water consumption was measured daily and plasma ascorbic acid (AA) content was assayed after differential treatment for 1 or 4 d. 2. The quail in the APP treatment groups drank significantly more than did those receiving untreated drinking water. 3. Supplementation with APP raised plasma AA concentrations substantially above those found in UDW quail. The lower AA concentrations found after APP treatment for 4 d rather than one may have reflected either inter-assay variation or limited intestinal absorption following excess ingestion. 4. Quail treated with APP showed less home-cage avoidance of a novel object and shorter tonic immobility fear reactions than did the UDW birds. The UDW quail showed remarkably similar avoidance and TI scores on test days 1 and 4. Conversely, continued treatment with APP further reduced avoidance scores but, although TI durations fell slightly with continued treatment there were no significant day effects. 5. It was concluded that APP supplementation can reduce underlying fearfulness but that it may not be necessary to continue treatment for longer than 24 h immediately prior to a known frightening event.