Interaction of diet and photoperiod on growth and reproduction in male golden hamsters.

Two basic diets (commercial rodent pellets or seeds) with or without supplements of carbohydrate were tested for growth and development, and effects on organ weights and serum calcium in male golden hamsters. The additional influence of photoperiod was measured. The data suggest that a seed diet alone is not adequate for growth. Addition of seeds and/or carbohydrate to the pellet diet increases growth rates substantially compared to the pellet diet alone. There are significant interaction effects on reproduction between diet and photoperiod indicating that diet can modify responses to short photic input. While reproduction remains essentially normal in seed-fed animals in long photoperiods, the rate of reproductive involution in short photoperiods is greatly enhanced. Added carbohydrate appears to offer some protection against the adverse effect of short photoperiods on reproduction. Even though calcium supplements to the diet increase serum calcium levels toward normal, growth rates are not improved. Addition of Tenebrio (grain beetle) larvae to the seed diet induces growth rates comparable to those of control animals, yet serum calcium levels remain significantly lower.