The use of predicted apparent metabolizable energy values to understand the oil and fat variability in broilers

The objective of this study was to analyze the predicted apparent metabolizable energy (AME) of different oil samples across Asia Pacific region and investigate the AME values in broilers of different ages (< 21 or > 21 days old). A total of 635 oil and fat samples consisting of 93 fish oils, 36 coconut oils, 70 crude palm oils, 42 refined palm oils, 43 soybean oils, 147 rice bran oils, 163 tallows and 41 lards were collected and analyzed over a span of eight years (2011 to 2018). The free fatty acid (FFA) content of oil and fat samples were analyzed through acid-base titration and the degree of saturation (ratio of unsaturation to saturated fatty acids; U:S) were determined with Gas Chromatography with Flame Ionization Detector (GC-FID). The FFA and U:S of the samples were then incorporated into the Wiseman equation to correlate the oil and fat qualities with the AME. Our survey revealed AME variations were prevalent in most of the oil types studied, with fish oils and tallows showing the largest energy gap within oil samples. The results showed that the predicted AME values for oil and fat samples differ across countries, even within batches from the same supplier. Taken together, our investigation suggests that there is a considerable variation in the AME values of oils and fats, which may affect the feed formulation precision.