Effects of Processing Methods on Phytochemical Compositions of Selected Plant Materials with Animal Nutrition Potentials

Plants contain significant amounts of bioactive compounds that have potential benefits for livestock and humans. This study evaluated the phytochemicals of some plant materials that have potential nutritional value for animals. In this study, fresh samples (six samples per plant material) of four leaves of Siam weed (Chromolaena odorata L.); African basil (Ocimum gratissimum L.); waterleaf (Talinum triangulare Jacq. Willd); and Mexican sunflower (Tithonia diversifolia Hemsl. A. Gray) were either air-dried (between 27 and 31 °C), oven-dried (at 65 °C) or freeze-dried (at −80 °C). The leaves were milled in a 1.0 mm sieve and the phytochemical contents of each leaf sample (in triplicates) were quantified. The quantified phytochemicals were flavonoids, tannins, beta carotene and xanthophylls for each of the leaves. Data were subjected to analysis of variance and significant means separated using the Duncan multiple range test. Flavonoids, tannins and xanthophylls were found to be the highest (p < 0.05) in most air-dried leaf samples compared to oven-dried and freeze-dried ones. Flavonoids, tannins, beta carotene and xanthophylls in the leaves showed that all leaf samples appear to have good potential for being used as natural feed additives such as egg yolk colourants in laying chicken feed. In vivo studies using birds are recommended.