(a) Experimental outline, showing triage into 3 groups treated with normal drinking water (control, N=10), or neomycin (N=8) or ampicillin (N=10). Treatment continued until 35 weeks of age. (b) Depigmentation was measured by scanning and image analysis every 2 weeks, starting at 4 weeks old. Antibiotic treatments resulted in significantly altered depigmentation at P<0.0001 for H0: slopes are equal. The slopes are 0.27 +/− 0.06 for neomycin, 0.6 +/− 0.16 for control mice and 1.45 +/−0.14 for ampicillin treated mice over the period of study. (c) Examples of terminal mouse scans. (****p<0.0001).