Influence of dietary protein quality on nitrogen balance and some blood parameters in cats

Three different dietary protein sources [greaves, poultry meal and fresh me at (beef heart)] were compared as dietary protein sources in four different dosages (26, 15, 10, 6 g of digestible crude protein per MJ digestible ene rgy in a complete mixed diet with rice, lard, cellulose and vitamin/mineral supplement) in 9 adult cats. Balance trials were conducted over 7 days, in blood samples sacral biochemical variables were analysed. The apparent dig estibilities of crude protein were affected by protein source and dosage. A pparent digestion rates of crude protein were 79-95% with beef heart, 78-89 % with greaves and 73-83% with poultry meal. N-balance was maintained with an intake of 300 mg N/kg BW/d, with beef heart only 205 mg N/kg BW/d were r equired (160 mg digestible N/kg BW/d). Activities of alanine aminotransfera se and glutamate dehydrogenase increased when diets with low protein concen trations were fed. It call be concluded that dietary, protein quality influ ences N-balance in adult cats and that protein supply can be reduced with h igh quality ingredients to 1 g of digestible crude protein/kg BW/d.