Effect of dietary plant and animal protein intake on sperm quality in monkeys

This study was conducted to evaluate the influence of animal and plant prot ein diets on sperm quality indices over 120 days, using the vervet monkey ( Cercopithecus aethiops), as a model. These experiments were divided into a 60-day period of high-protein consumption (+/-17% crude protein), followed by a 60-day term of sustainable protein intake (+/-9% crude protein). All t he diets were designed to be similar, except for the source of dietary prot ein that the animals consumed. High-protein diets containing milk solids or maize + legumes had no significant effect on sperm quality parameters over the first 60 days. During the next 60 days of the investigation, sustainab le plant and animal protein diets had differential effects on a number of s perm quality indices. When compared to the plant-based diet, the monkeys th at were given the animal protein diet containing milk solids had lower sper m counts (p<.04), reduced sperm motility (p =.04), higher sperm midpiece ab normalities (p <.05), and a trend (p =.10) towards increased sperm head def ects. These findings shed some light on the impact of variable dietary prot eins on sperm quality, but should be followed by longer-term investigations around this important reproductive health issue.