Carbohydrate metabolism in intensive growing and fattening pigs on low protein diets with various levels of metabolizable energy and amino acids
The object was to study the efficiency of diets with decreased level of crude protein in crossbred (Landrace × Large White) growing and fattening pigs. The pigs at 65 d of the age were assign to 3 groups (n=10) fed barley-wheaten concentrates with CP level 120, 114 and 107 g/kg for periods of growing and fattening respectively with addition of lysine, methionine and threonine up to norm (I group, control) or by 22-26% above norm (II group). The level of CP in III group was increased up to 152, 135 и 118 g/kg for periods of growing and fattening respectively by means of addition of soybean meal and intake of limiting amino acids was increased by 40-52% compared to control. Futhermore, in II and III groups the ME intake was increased by 5 and 10% compared to control by means of addition of vegetable oil. The data of blood metabolic profile and enzymatic activities in liver and muscle tissue suggest that the experimental diets were relatively balanced compared to control group. The activity of pyruvate carboxylase and fructosediphosphatase in liver and that of pyruvate kinase in muscle tissue decreased by the age indicating on diminished role of glucose and increased utilization of fatty acids for energy supply. By the author's opinion, the diets studied do not cause any significant deviations in the processes of carbohydrate metabolism.