ASSESSMENT OF VOLATILE FATTY ACIDS AND METHANE PRODUCTION IN VITRO OF OPUNTIA FICUS-INDICA CLADODES IN AN ALGERIAN ARID AREA

The main objective of the present study was to evaluate the volatile fatty acids (VFAs) and methane (CH₄) production of cactus Opuntia Ficus-Indica (O. ficus indica) Cladodes, Medicago sativa L. (M. sativa) and barley straw (H. vulgare) using chemical composition and in vitro gas production. There were significant (p<0.05) differences among studied samples in all measured nutrients except dry matter (DM) value. O. ficus indica showed particularly the highest Ash content (284.07 g/kg DM). The crude protein (CP) of the studied feedstuff ranged from 51.41 to 156.09 g/kg DM and it was especially high within M. sativa and low in H. vulgare. No significant difference was observed in pH values, total VFAs, propionate concentrations and CH₄ production (ml/100 gas) among plants species studied. The lowest Acetate concentration was observed in H. vulgare (711.17 mmol/mol) and M. sativa (715.33 mmol/mol), respectively (p < 0.05). The maximum in vitro gas production was recorded with M. sativa and H. vulgare. Based on the results, it can be concluded that O. ficus indica could replace common plants species, especially in the arid and semi-arid areas in which livestock production frequently suffers from low efficiency and big losses. Furthermore, these plantations in agroforestry development could consolidate the protection of the environment against erosion, allowing the fixation of the soil and its protection against water erosion.