Palm kernel expellers is a coproduct of the production of palm kernel oil. Unlike palm kernel meal, which is produced after the oil is removed from the fruits of oil palms using solvent extraction, palm kernel expellers are produced via mechanical extraction. The lysine content of palm kernel expellers is low relative to soybean meal. Additionally, the high fiber content of palm kernel expellers means that it contains less digestible and metabolizable energy than soybean meal or corn. These factors limit the inclusion rate of palm kernel expellers in swine diets.  However, despite these limitations, palm kernel expellers can provide significant protein in swine diets and may be used to reduce feed costs.

An experiment was conducted to test the hypothesis that palm kernel expellers may replace some corn and soybean meal in phase 2 diets fed to weanling pigs without negatively affecting growth performance.

A total of 128 pigs were weaned at approximately 20 days of age. All pigs were fed a common phase 1 diet for 14 days post-weaning and then were randomly allotted to four treatment groups. Pigs had an average body weight of 9.76 kg at the start of the experiment. Four phase 2 diets were formulated. The basal diet was based on corn and soybean meal, 4% fish meal, and no palm kernel expellers. Three additional diets were formulated by including 0, 5, 10, or 15% palm kernel expellers in the diets at the expense of corn and soybean meal. Diets were formulated to contain equal amounts of metabolizable energy, digestible amino acids, and digestible phosphorus. Concentrations of metabolizable energy, digestible amino acids and digestible phosphorus in palm kernel expellers were measured in the same source of palm kernel expellers as the source that was used in this experiment.

Individual pig body weight was recorded at the start of the experiment, after 10 days, and at the conclusion of the trial after 20 days. Daily feed allotments and unconsumed feed were also recorded. From these data, average daily gain, average daily feed intake, and average gain to feed ratio were calculated for each treatment group.

Body weight at day 10 and day 20 showed a linear decrease (P < 0.05) as the concentration of palm kernel expellers in the diet was increased (Table 1). Average daily gain in the first 10 days and over the whole period also showed a linear decrease (P < 0.05) as the concentration of palm kernel expellers in the diet was increased. Average daily feed intake and gain:feed ratio were not affected by increasing inclusion of palm kernel expellers. These results indicate that performance cannot be maintained if palm kernel expellers are used in diets for weanling pigs even if diets are balanced for metabolizable energy and digestible amino acids and phosphorus. It is possible that the reason for this observation is that the concentration of fiber in palm kernel expellers is much greater than in corn and soybean meal, which may have a negative impact on performance.

• Final body weight and average daily gain decrease linearly with increasing inclusion levels of palm kernel expellers, at the expense of corn and soybean meal, in phase 2 diets fed to weanling pigs.
• It is possible that the high concentration of fiber is the reason for the reduced concentration of metabolizable energy in palm kernel expellers, and therefore for the reduced growth performance of pigs fed palm kernel expellers at the expense of corn and soybean meal.

Table 1. Growth performance of nursery pigs fed diets containing 0, 5%, 10%, or 15% palm kernel expellers (PKE)

This report is based on unpublished data by N. W. Jaworski, J. Shoulders, J. C. González-Vega, and H. H. Stein.