Do mice grow normally with an egg-only diet?

Chicken egg (egg) is a conventional food that contains every nutrient required for the growth of the chicken embryo. Eggs contain high amounts of important proteins and fat with a very low amount of carbohydrates, and also contain all vitamins and minerals needed for the chick to develop. We took 5-week-old mice and raised them for 6 months consuming an egg-only diet, and examined their health conditions. We found that mice raised on this diet grew to the same weight as mice fed a normal chow diet (ND), and remained healthy until they were 8 months old. As expected, the levels of total ketone bodies and 3-hydroxybutyrate were approximately 3 times higher in the egg-only mice than in the ND mice. Total cholesterol, HDL cholesterol, triglycerides, and free fatty acids in the serum of the egg-only mice were higher than those in the ND mice. Surprisingly, serum glucose levels in the egg-only mice were nearly the same as those of the ND mice at all points. Because of the high amount of fat in the diet (approximately 60% of total calories), we expected that the egg-only mice would develop fatty liver or other metabolic diseases. However, over the 6-month examination period, we observed no pathological changes in the livers of the egg-only mice serologically and histologically. Serum alanine transaminase and aspartate transaminase levels were normal and no fat droplets were observed in the livers of the egg-only mice.