Preliminary observations on the use of the rat as a model for the pig in the determination of apparent digestibility of dietary protein

Abstract Diets containing barley meal, meat and bone meal, fish meal, or pea meal as the sole protein source were fed to growing rats and pigs. The apparent digestibility of dietary crude protein was determined on samples of ileal digesta and faeces. Ileal contents were collected after slaughter of the rats, and by means of simple T‐piece cannulae in the pigs. There was close agreement between the animal species for the ileal digestibility of crude protein in barley meal, meat and bone meal, and fish meal, but not for pea meal. The respective mean values for the rat were 0.66, 0.69, 0.82, and 0.81, and corresponding values for the pig were 0.71, 0.66, 0.82, and 0.69. Faecal digestibilities of crude protein were generally higher than the corresponding ileal digestibilities and were also higher in the pig than the rat.