Sustainable ruminant nutrition in West Africa by in vitro characterization of cashew apple by-products

Abstract

Cashew trees (Anacardium occidentale L.) are planted for primarily their nuts, but they also generate apples which are mostly thrown away due to their astringent taste. The current study aimed to explore the possible utilization of cashew apple by-products (CABP) in West Africa as an alternative feedstuff for small ruminants’ nutrition. To achieve this aim, five parts of cashew apple by-products (whole, up, down and middle part, and pomace) of two cashew varieties (red and yellow) were collected in two different agroecological zones (Sudanian Zone, SZ and Sudano-Guinea Zone, SZ) to be characterized for the chemical composition, including polyphenols and sugars, and the in vitro fermentation pattern. In general, the results showed that CABP characteristics depend more on sampling area than on variety. The dry matter (DM) in SZ and SGZ varied from 12.76 to 26.10 % and 7.41–22.9 %, respectively. The pomace showed the highest crude protein, lipids, and neutral detergent fiber (NDF) content (SZ: 9.48, 3.94 and 31.66 % DM; SGZ: 14.03, 4.94 and 34.12 % DM, respectively) but the lowest nonstructural carbohydrate (NSC) and sugar for both zones. Regarding the in vitro fermentation, the organic matter degradability (dOM) was higher in the middle part (73.73 %) and whole apple (61.62 %) of SZ and SGZ, respectively. In contrast, the pomace from both zones showed the lowest in vitro fermentation parameters. The total polyphenols were more concentrated in the CABP from SZ (whole: 2736 μg/g DW; pomace: 3813 μg/g DW) compared to those from SGZ (whole: 1755 μg/g DW; pomace: 1374 μg/g DW). Results suggest that CABP should be collected in each cultivation zone regardless of variety, separating pomace from other by-products and may be used as alternative feedstuff for small ruminants during the dry season in the West Africa region.