Acclimation and testing periods
Supplier Mice were obtained from The Jackson Laboratory (JAX®, Bar Harbor, ME) Mice identification Microchips (Locus Technology, Inc., Manchester, MD 21102) were implanted subcutaneously to identify mice used in aging-related phenotype studies After weaning, the mice were incorporated into the study in staggered cohorts Mice received ad libitum access to autoclaved pelleted diet with 6% fat (Lab diet 5K52, PMI Nutritional International, Bentwood, Mo) Mice were given ad libitum access to acidified water (pH 2.8-3.1) Mice of the same sex were housed 4/pen in pressurized individually ventilated (PIV) polycarbonate cages measuring 31 x 31 x 214 cm divided into two pens supplied with high efficiency particulate air (HEPA) filtered air (Thoren Caging Systems Inc., Hazleton, Pennsylvania) Autoclaved white pine shavings (Crobb Box Co. Ellsworth, Maine) were used as bedding 12h:12h light-dark cycle Relative humidity ~50% 21-23°C The mice were kept in a barrier facility, where room entry procedures required personnel to don caps, face masks, disposable gowns, shoe covers, and gloves. Personnel working in this facility were not allowed to have rodent pets. Mouse colonies in this facility were monitored four times a year for (and are free of) 15 viruses (mouse hepatitis virus, two mouse parvoviruses, reovirus, Theiler's mouse encephalomyelitis virus, ectromelia virus, mouse rotavirus, thymic virus, pneumonia virus of mice, Sendai virus, murine cytomegalovirus, lactic dehydrogenase-elevating virus, K virus, mouse adenovirus, and polyoma virus), 17 bacterial species (including Helicobacter spp. and P pneumotropica), two Mycoplasma spp., external and internal parasites, and Encephalitozoon cuniculi.