Mature fruits of Gliricidia sepium and Leucaena leucocephala plants have potential as inexpensive protein and mineral supplements for ruminants

Multifunctional leguminous trees like Gliricidia sepium Jacq. (Steud.) and Leucaena leucocephala Lam. (de Wit) are ideal for sustainable agro-ecological farming systems. They are commonly used in alley cropping to provide a sustainable source of nitrogen to cultivated crops or in silvopastoral systems where the leaves are used as livestock feed. However, these plants produce fruits that are not widely used. This study evaluated the nutritive value of mature fruits from G. sepium and L. leucocephala plants to determine their potential as supplemental feedstuffs for ruminants. Mature fruits were collected from 15 plants of each species and evaluated for crude protein (CP), total digestible nutrients (TDN), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, non-fiber carbohydrates, total digestible nutrients, minerals, phytochemicals, in-vitro ruminal dry matter degradability (IVDMD) and 48-h (h) in-vitro ruminal organic matter digestibility (IVOMD). The concentration of CP (242 g/kg DM) was approximately 28% higher in G. sepium fruits. The TDN (552 g/kg DM), NDF (560.1 g/kg DM) and 48-h IVOMD (590 g/kg) were superior in L. leucocephala fruits. Similarly, L. leucocephala fruits had significantly higher minerals (i.e., calcium, magnesium, potassium, among others). However, G. sepium fruits had lower concentrations of soluble and insoluble condensed tannins and mimosine. The immediately degradable fraction (265.9 g/kg DM), potential degradability (621.6 g/kg DM), and effective degradability (438.9 g/kg DM) values were higher in L. leucocephala fruits. We concluded that mature fruits of G. sepium plant may be a better protein supplement for poor quality grass forages than L. leucocephala because of higher CP and lower phytochemicals contents.