Dietary modulation of estrous cyclicity in singly and multiply housed C57BL/6J mice.

Two commercial diets differed markedly in their ability to support estrous cyclicity in both singly and multiply housed, 3- to 4-month-old virgin C57BL/6J mice. When fed a breeder diet developed to promote reproduction, mice had shorter cycles and a decreased number of acyclic intervals than when fed a standard diet. In addition, the breeder diet counteracted the inhibitory influence of multiple housing on cyclicity. Although the breeder diet had a three-fold higher fat content and a two-fold lower fiber content, it was not possible to ascribe a causal role to these differences since the diets differed in the relative amounts and sources of many other components.