Effects of Energy intake and, dietary protein concentration on energy partition and energetic efficiency in growing pigs

Abstract

The influence of energy intake, and dietary protein concentration on the energy partition and the rates of energy expenditure, in growing pigs were evaluated in a 2x2 factorial arrangement The factors were two feeding levels and two dietary protein concentrations, each fed to separate 6 entire males. Energy and nitrogen balances and calorimetric measurements were recorded simultaneously in each animal when weighed 5.4.5 ± 3.7 kg. Energy retained as protein and fat increased with level of feeding. Increased protein  intake resulted into incresed rate of heat production and protein energy retention and low rate of fat energy retention. The energy requirement for maintenance was slightly lower in animals fed on the high compared with those on low-protein diets. The partial efficiency of ME utilisation for growth, was poor in the animals fed high dietary protein concentration (kg 0.504 against 0.601). The net energetic efficiency for protein deposition was also lower (kp 0.34 against 0. 71) and fat deposition higher (kg 0. 80 against 0.66) in the animalsfed on high relative to those on low protein diet. The results indicate that the energy cost of protein accretion increases within increasing dietary protein concentration.

Keywords: Protein, energy, intake, efficiency, pigs

Tanzania J. Agric. Sc.(2001) Vol. 4 No. 2, 75·82