A Survey of quality of oils used in Thai pig farms

Abstract

Oil is commonly added into pig diets to increase energy in animal feed formulation. Fifty-eight oil samples: 1) crude coconut oil (n=11), 2) crude palm oil (n=6), 3) refined palm oil (n=6), 4) crude soybean oil (n=4), 5) refined soybean oil (n=5), 6) crude rice bran oil (n=6), 7) crude chicken oil (n=6), 8) crude lard (n=5) and 9) used oil (n=9) from pig farms, feed mills and traders in Thailand were collected and analyzed for quality by measurement of pH, percentage of total polar compounds (% TPC), peroxide value (PV), free fatty acid (FFA), iodine value (IV), percentage of impurity (% impurity) and percentage of moisture (% moisture). Results not only showed variations of oil quality in different kinds of oil, but also high variations of several parameters in some oils. As for palm oils, crude palm oil had higher FFA than refined palm oil (p=0.033), but significantly lower PV (p=0.005). The parameters of pH and FFA could be used for the identification of crude and refined grades of soybean oil. Correlation of % TPC between Thai commercial test kit and FOM 310 meter showed low positive correlation (approximately 25%). Therefore, the FOM 310 meter was recommended for checking % TPC of oils in pig farms and feed mills. Overall, the results of this study suggested that oil quality should be evaluated by the following parameters: % TPC, PV, FFA, IV, % impurity and % moisture.