IN VITRO SCREENING OF SELECTED WILD LEGUME SEEDS FOR ENTERIC METHANE MITIGATION POTENTIAL

Résumé

The study was conducted to evaluate the chemical composition, in vitro gas production and methanogenic property of five tropical wild legume seeds (Luffa cylindrica, Piliostigma thonningii, Detarium microcarpum, Daniellia oliveri and Afzelia africana). Chemical compositions were analysed, while total gas volume was measured and methane estimated by using 4 ml of 10 M NaOH. All samples (% DM) had high crude protein (22.05 –39.9) and moderate fibre concentrations (NDF, 37–49.33; ADF, 20 –22.33 and NFC, 16.78 – 30.39). There were variations (P<0.05) in the dry matter (DM), crude protein (CP), non-fibre carbohydrates (NFC), neutral detergent fibre (NDF) and anti-nutritional contents of the selected tropical wild legume seeds. Total gas volume produced by the seed meals steadily increased and was most pronounced (P<0.05) in Afzelia africana seed meal (60.67 ml/200 mg DM), while the least gas volume was recorded against Piliostigma thonningii (37.83 mL/200 mg DM). Methane mitigation potential ranged from 0.15- 0.20 mL/200 mg DM with Afzelia africana having the highest and Piliostigma thonningii the least values. Results show that all the selected wild legume seeds have good nutrient profile, moderate and safe
levels of anti-nutritional factors, relatively high in vitro degradability and methane mitigation potential which qualify them as suitable feed supplements to low quality basal diets for ruminants. However, Afzelia africana had the best methane mitigation potential and can, therefore, be regarded as the best suitable alternative plant protein source for improved and environmentally friendly ruminant production.