In a recent study conducted by our research group (in collaboration with various universities such as Aarhus University, Universidad de Sevilla, among others), we aimed to analyze the diet of wild rabbits and the levels of certain nutritional metabolites.

To achieve this, we examined protein intake levels and analyzed urea levels (an indicator of protein excretion). This allowed us to calculate a ratio between urea generated per gram of protein ingested.

This ratio would indicate, for each unit of ingested protein, how much is being “lost.” Thus, we could infer that animals with lower values would utilize protein more efficiently than those with higher values. Which sex would be more efficient?

As depicted in Figure 1, the levels of this ratio were significantly lower in females, indicating that they were more efficient in utilizing the protein they consumed.