Effects of castration, level of feeding and body weight on Energy partition and efficiency of energy utilisation in growing pigs

Abstract

Efects of castration, feeding level and body weight on energy partition and efficiency of energy utilisation in growing pigs were studies. Eighteen entire and 18 castrated males, fed on either high (3.34 x maintenance) or low (225 x maintenance) level of feeding in a 2x2 factorial design, with 9 pigs per treatment were used. Energy nitrogen balance and calorimetry were recorded at 30, 60 and 90kg body weight. Increased feeding level resulted into increasing rates of energy (ER), protein energy (Pe) and fat energy (Fe) retention by 0.45, 0.29 and 0.62, respectively.  Castration increased ER and Fe by 0.16 and 0.42, respectively but decreased protein energy retention by 0. 13. Energy requirement for maintenance (ME_m) was 0. 10 higher in the entire than castrated males and tended w increase with increased protein energy retention. Net energetic efficiences for protein (kp) and fat retention (kj) were higher for the entire (0.61 and 0.98) than for castrated males (0.56 and 0.92) The results indicate that an increase in the rates of energy expenditure with increased lean tissue growth potential may be attributed to increased energy requirement for maintenance.

Keywords: Body composition, pigs, energy metabolism; energetic efficiency

Tanzania J. Agric. Sc. (2001) Vol. 4 No 1. 15-22