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Effect of dietary net energy concentrations on the growth performance of growing gilts housed individually
Dietary net energy (NE) concentrations influence pig performance, but the information for their effects on young gilts has been limited. Therefore, the objective of this experiment was to determine the effect of different NE concentrations in diets on the growth performance of growing gilts. A total of 60 growing gilts (Landrace × Yorkshire; initial BW = 15.9 ± 0.55 kg) were allotted to 5 dietary treatments of 9.6, 10.1, 10.6, 11.1, or 11.6 MJ NE/kg with 12 replicate pens and 1 pig per pen in an 28-d feeding experiment. Ratios between standardized ileal digestible AA and NE concentrations in all diets were similar. The NE and AA concentrations in diets were calculated based on the values from NRC (2012). Pigs were allowed ad libitum access to feed and water. The NE concentrations of 5 diets used in the growth trial were also determined based on digestible nutrients, DE, and ME measured in metabolism experiments with replicated 5 × 5 Latin square design using 10 growing pigs (initial BW = 15.9 ± 0.24 kg). Results indicated that calculated NE concentrations in diets were close to measured NE concentrations (9.5, 10.1, 10.4, 11.0, and 11.4 MJ NE/kg) in diets. The final BW, ADG, and ADFI were not affected by dietary treatments. However, there was a quadratic relationship (P = 0.01) between feed efficiency and dietary NE concentrations (0.51, 0.50, 0.49, 0.50, and 0.52 for 9.6, 10.1, 10.6, 11.1, and 11.6 MJ NE/kg of diets, respectively). The NE intake per BW gain (MJ NE/kg of BW gain) was increased (linear and quadratic, P < 0.01) with increasing NE concentrations in diets. In conclusion, dietary NE concentrations affect feed efficiency and NE intake per BW gain of growing gilts.
Keywords: growing gilts, growth performance, net energy,