Chemical composition and in vitro degradation of red and white mesquite (Prosopis laevigata) pods

Abstract

The objective of this study was to compare the chemical composition and ruminal degradation of whole pod, exomesocarp, endocarp and seed fractions of red and white mesquite pods. The pods contained on average 220 g free sugars, 78 g crude protein, 21 g fat per kg dry matter (DM), and a potential DM degradation of 163 g/kg. Contaminant fungi (mostly Aspegillus spp.) count was low. Unsaturated fatty acids, mainly linoleic acid, were the predominant (~50%) fatty acids in whole pods and seeds. Sucrose was the largest free sugar proportion. The highest fibre content was found in the endocarp, the highest free sugar was found in the exomesocarp, and the highest crude protein content was found in the seeds. Tannins were more abundant in red pods (0.4 mg/100 g DM) than in white ones. Some differences in nutritional values were found between red and white pods and their components (exomesocarp, endocarp and seeds), although both have a potentially high nutritive value. Whole pods and the endocarp can be used by ruminants; seeds can be used by simple stomach animals; and the exomesocarp can be used in human nutrition because of its low glycaemic index properties

Keywords: Degradation rate, fatty acids, sugar, tannins