Broilers
Palm kernels were found to be a valuable alternative ingredient for increasing the metabolizable energy levels of broiler diets based on soybean meal, maize grain or sorghum. However, results are contradictory. In Nigeria, the inclusion of more than 5% palm kernels in broiler diets reduced growth and feed intake, and increased the feed to gain ratio (Oruwari et al., 1996). In Costa-Rica, palm kernels could be included at up to 20% in broiler diets to increase energy or replace tallow and soybean oil, though performance decreased when they replaced more than 50% of the soybean oil (Zumbado et al., 1992). When included at 20% in broiler diets, variations in endocarp content (from 0 to 15%) did not significantly affect broiler performance (Jackson et al., 1996).
Laying hens
In laying hens, palm kernels were found to be a useful alternative to maize grain when this ingredient was scarce and kernel prices were low. Palm kernels could replace up to 33% of the maize grain in the diet without significantly influencing feed intake, average egg weight, hen-day production, body weight gain, protein and fibre retention though fat retention was affected (Adekoya et al., 2004).
Energy values
The energy value of palm kernels is high: TMEn values range from 18.8-20.0 MJ/kg DM for cockerels (Zumbado et al., 1996) to 25.5 and 25.6 MJ for broilers and laying hens respectively (Oruwari et al., 1996). Contamination with pericarp residues influences the nutritional value of palm kernels: TMEn values decreased from 20.0 to 18.8 MJ/kg DM when the amount of endocarp increased from 0 to 12% (Zumbado et al., 1996).
