Energy metabolism of growing pigs

Three trials were conducted to study the energy metabolism of growing pigs. In trial 1, 16 pigs (8-10 kg) were used in a 28 d comparative slaughter experiment to determine the energy value of wheat bran. Addition of wheat bran in the diets increased ADG linearly (P \u3c.01), but had no effect on F:G ratios. Apparent digestibility coefficients (ADC) of DM, N and fiber components decreased linearly (P \u3c.01). Digestible and ME (kcal/g) decreased linearly (P \u3c.01) with addition of wheat bran. Total heat production and total VFA content in the cecum increased linearly (P \u3c.01 and P \u3c.05) with addition of wheat bran. Components of daily gain including indispensable amino acids (AA), increased (P \u3c.01). The average values (kcal/g DM) for wheat bran were GE, 4.57; DE, 3.36; ME, 3.20; MEn, 3.19 and NE, 1.1. Feeding wheat bran to the pigs resulted in a low efficiency of ME utilization;A second trial was designed to determine the production and absorption of VFA and other energy metabolites (glucose, lactic acid and D-B-hydroxybutyric acid) in pigs fed wheat bran. Addition of wheat bran tended to increase the production of VFA in the large intestine. Portal arterial differences of VFA increased, while portal arterial differences of the metabolites decreased when wheat bran was added to the diets. The lower efficiency of ME utilization observed when wheat bran was fed to pigs may be because of fermentative losses in the large intestine and lower efficiency of VFA utilization as an energy source for the pig;Trial three was designed to determine the energy requirements for maintenance and growth of the Chinese pig. Sixteen Chinese pigs were used in a 28 d comparative slaughter experiment. The pigs were fed a corn-soy diet at 3, 4, and 5% of body weight. ADG increased linearly (P \u3c.01) with the level of feeding but ADC of DM, N and GE were not affected. Level of feeding increased dry matter and fat percentage of the empty body (P \u3c.01), but decreased water percentage (P \u3c.01). Components of the daily gain, including indespensable AA increased linearly (P \u3c.01) with the level of feeding. Fat to protein ratio of the empty body gain increased linearly (P \u3c.01) with the level of feeding. The NE for maintenance of the Chinese pig was 77.6 kcal per d per kg[superscript].75. The Chinese pig utilized 64% of the ME for NE of maintenance and growth