A total of 32 B6 male mice (16 +/+ and 16 Lwt/+) were weighed to the nearest 0.1 g every 7 days from 50 to 100 days of age. Sacrifice weight (SACW) was determined at 100±4 days, approximately 12 hours prior to dissection. Beginning on day 85, food and water intake were measured at 3 day intervals until sacrifice. At sacrifice, mice were anesthetized with isoflurane until the toe-pinch withdraw reflex and corneal reflex was lost and then placed over a grid without stretching to measure body lengths. Nasal anal (NA) and nasal tail (NT) lengths were measured to the nearest 1 mm by measuring the length from the tip of the nose to the base of the tail and to the end of the tail, respectively. Then the femoral, gonadal, mesenteric and retroperitoneal fat pads, and major organs (liver, spleen, kidney and testis) were harvested and weighed immediately. Empty carcass weight (ECW) (skinned carcass without organs, fat, nor tail) was also determined. Femurs were then dissected and measured to the nearest 0.1 mm with a Vernier scale. Total fat (TF) was calculated as the sum of all fat pads.
