SUCROSE AS AN ENERGY-SOURCE FOR GROWING PIGS - A COMPARISON OF THE EFFECTS OF SUCROSE, STARCH AND GLUCOSE ON ENERGY AND PROTEIN RETENTION

The effects of dietary sucrose, glucose and starch were compared to determine whether sucrose as an energy source affected energy or protein metabolism of growing pigs given food either frequently or once daily. Three experiments were conducted using three diets (0.8 g lysine per MJ digestible energy (DE)) containing sucrose, starch or glucose, respectively. In the first experiment, the DE contents of the diets were determined. In the second, the diets were given either once daily (08.00 h) or frequently (3-h intervals) to growing pigs (20 to 45 kg live weight) and growth responses, blood characteristics and energy, protein and fat retention measured. In the third experiment, the three diets were given to seven pigs (50 kg live weight) either once daily or frequently to monitor further the effects on plasma triglycerides, glucose, urea and insulin levels. Growth rate, on a carcass basis, was slightly lower in pigs given glucose relative to starch (P < 0.05) but there was no effect of carbohydrate source on the retention of energy, protein or fat. Plasma triglyceride levels were lower in pigs given starch (P < 0.05) whilst plasma glucose and insulin concentrations were higher immediately after feeding in pigs given food once daily (P < 0.05, P < 0.01). All three carbohydrate sources were used less efficiently by the pigs for energy, protein and fat deposition with once daily compared with frequent feeding (P < 0.01). Overall, these results indicate that sucrose as an energy source does not effect energy or protein metabolism by the growing pig. It appears that the metabolism of frutose within sucrose had no effect on metabolism.