Meeting Abstract
P1.22 Monday, Jan. 4 The effects of water availability on tissue rebuilding in migratory blackcaps during stopover MIZRAHY, O.; BEN-HAMO, M.*; BAUCHINGER , U.; PINSHOW, B.; Ben Gurion University ; Ben Gurion University ; Ben Gurion University ; Ben Gurion University ortalmi@bgu.ac.il
We examined whether migrating blackcaps (Sylvia atricapilla), refeeding after a period of simulated in-flight starvation, replace lean mass (ml) and pectoral muscle mass (PM) faster with access to drinking water than without. Ten birds were randomly assigned to each of three groups: water ad libitum; 0.5 h/d access to water; no water; all were fed mealworms (~60% water) ad libitum for 6 d. Thirty other birds were divided into two groups and offered either water ad libitum or access to water for 0.5 h twice a day along with a standard insect based diet (~33% water) ad libitum for 6 d. In both experiments, we measured body mass (mb), PM index (PMI), food (DFI) and water intake (DWI). Also, ml and fat mass (mf) were measured using dual energy x-ray absorptiometry. Mean DWI was significantly different among the groups in both experiments (RM-ANOVA F2,28= 27.6, p< 0.00001 and F1,21=24.2, p< 0.0001). Despite this, no differences found in mass specific DFI in either experiment (F2,28=0.7, NS and F1,21=0.05, NS). PMI was not affected by water availability when mealworms were provided (F2,28=0.49, NS), but when fed the standard diet, the effect on PMI was positive (F1,21=4.90, p< 0.05). The change in ml did not differ among groups fed mealworms (F2,28=1.92. NS), but was positively affected by the availability of drinking water in birds fed the standard diet (F1,15=9.85, p< 0.01). The data support our prediction in that, when blackcaps were fed a relatively low water content diet, drinking water positively affected the bird’s PMI and ml gain. Although preformed and metabolic water gained through eating mealworms is apparently sufficient for blackcaps to rebuild lost tissues, given access to water the birds drink prodigiously, perhaps allowing more time for activity.
