Improvement of quality and digestibility of moringa oleifera leaves feed via solid-state fermentation by aspergillus Niger

Abstract

The Moringa oleifera leaf is an important source worldwide with a high nutritional value and functions in food and feed that may also treat a myriad of ailments but the leaf has low organoleptic properties and digestibility. To overcome this shortcoming, a novel Aspergillus Niger was isolated from the Moringa leaf material. The fungal strain grows well on moist Moringa leaves and requires no additives. After performing a single factor test for temperature, moisture, inoculation size, and fermentation, the optimized condition was determined by using a response surface method, followed by a small-scale production test. The pleasant, sweet smelling aroma in the fermented leaves was then generated, supplementing than its native repulsive smell. The protein content and digestibility of the leaves increased by 23.4 % and 54.4 %, respectively; the direct-fed microbes reached up to 1.99 × 109 CFU per gram of fermented freeze-dried Moringa leaves. Digestive lignocellulolytic enzymes were substantially produced with 2.97 ± 0.24 U.g-1 of filter paper activity and 564.9 ± 37.4 U.g-1 of xylanase activity. Moreover, some functional components, such as flavonoids and γ-Aminobutyric acid content, were also significantly increased compared to that of the unfermented leaves. In conclusion, the feed quality and digestibility of Moringa oleifera leaves were greatly improved via solid-state fermentation by Aspergillus Niger. Fermented Moringa oleifera can be used as a potentially high-quality feed alternative for the animal industry.