Effect of analytical method on the determination of moisture percentage of some common feed ingredients for poultry

Abstract

The moisture content of feed ingredients plays a vital role in poultry feed processing, as it directly impacts the formulation of nutritionally balanced diets while influencing the quality and stability of feed. Therefore, accurate determination of the moisture content of feed ingredients is crucial in the feed processing industry. This study aimed to compare the accuracy of three oven drying methods (AOAC 930.15 at 135 ◦C for 02 hours, NFTA 2.1.4 at 105 ◦C for 03 hours, and ISO 6496:1999 at 103 ◦C for 04 hours) with the Karl Fischer (KF) chemical titration method, which is a reference method for moisture determination. Maize, soybean meal (SBM), poultry offal meal (POM), and fish meal (FM) were used as the feed ingredients. Moreover, the additive effect of moisture content in a compound feed mixture was also evaluated. All test feed ingredients were analysed for their proximate composition. FM and POM reported the highest crude protein (CP: 56.9±0.33%) and ether extract (EE: 18.6±0.45%) contents, respectively. Compared to the KF method, three oven drying methods overestimated the analysed moisture content (P < 0.05) in maize, SBM and FM. Three oven-drying methods underestimated (P < 0.05) the moisture content in POM. Of the methods tested, maize, SBM and FM at 103 ◦C for 04 hours have been identified as the most reliable alternative to KF titration. For POM, drying at 135 ◦C for 02 hours was the most reliable alternative. None of the oven-drying methods demonstrated an additive effect on moisture content in the compound feed mixture. However, drying at 103 ◦C for 04 hours provided the minimum statistical and numerical deviation between analysed and predicted moisture contents of the compound feed mixture. The present study concludes that the moisture values obtained by three oven-drying methods do not always align with those from Karl Fischer titration and vary with the ingredient type. When the additive effect on moisture content in compound feed mixtures is concerned, drying at 103 ◦C for 04 hours can be recommended as a practical alternative to Karl Fischer titration.