Phytochemical profile and in vitro evaluation of cassava (Manihot esculenta Crantz) foliage as ruminant feed with/without green banana flour

Abstract

Cassava (Manihot esculenta Crantz) is a crucial crop in tropics and subtropics, primarily cultivated for its tuber. However, its foliage is rich in protein and can supply essential elements for ruminants. The objective of this study was to evaluate the phytochemical compounds by Gas chromatography-MS (GC-MS) and the main phenolic by High Pressure Liquid Chromatography (HPLC) present in cassava foliage, along with the fermentation pattern using a semi-automated gas production (GP) system. The in vitro evaluation was carried out for four diets formulated as follows: T₁ (alfalfa: grass hay at ratio of 30: 70); T₂ (alfalfa: grass hay: banana flour 30:60:10); T₃ and T₄ (replaced alfalfa in T₁ and T₂ with cassava foliage, respectively). The addition of green banana flour aimed to increase the diets' energy. The GC-MS results indicated that cassava foliage showed a large number of valuable bioactive components, with the biflavonoid isoginkgetin representing the major component at 25.33% of total peak area percentage. The HPLC analysis declared that rutin, gallic acid, and ferulic acid were the main phenolic compounds presented in cassava foliage ethanolic extract. The accumulative gas after 24 h of incubation was significantly lower with cassava diets compared to alfalfa diets, being 119.3 versus 130.1 ml/g DM, respectively. The degradation of both organic matter and neutral detergent fiber was significantly higher with alfalfa compared to cassava diets, while there was no significant difference between alfalfa and cassava diets on final pH, ammonia concentration and protozoal count. Banana flour inclusion, regardless of the forage type, decreased the accumulative gas after 24 h of incubation with about 9% compared with no banana addition. The use of cassava foliage in ruminant diets considered a promising protein source with valuable bioactive components that could have a positive effect on animal health and production.