Leucaena leucocephala leaves and prickly pear (Opuntia ficus-indica) as substitutes for alfalfa hay (Medicago sativa L.) and their effects on the gas and methane production, prevalence of methanogens and patterns of ruminal fermentation in vitro

Abstract

The aim of the study was to evaluate the replacement of alfalfa hay with Leucaena leucocephala leaves and prickly pear (Opuntia ficus-indica) as an alternative forage, on gas and methane production, ruminal fermentation patterns and total amount of methanogens during in vitro fermentation. Four treatments were evaluated: (T1) alfalfa hay + concentrate (50 : 50%, DM); (T2) alfalfa hay + Leucaena leaves + concentrate (30 : 20 : 50%, DM); (T3) alfalfa hay + prickly pear + concentrate (30 : 20 : 50%, DM) and (T4) alfalfa hay + Leucaena leaves + prickly pear + concentrate (30 : 10 : 10 : 50%, DM). The higher gas production from of soluble fraction (A) and rate gas production (Kd) values, ammonia-N (NH3-N) concentrations and propionate were found in T1 and lower in T2 (p<0.05). Nevertheless, the inclusion of Leucaena leucocephala in the diet decreased the methane production and did not affect the total of methanogens. Results showed that the replacement of alfalfa hay by Leucaena leucocephala and Opuntia ficus-indica in a diet do not affect the main variables of in vitro gas production, ruminal fermentation patterns and methanogenic microorganisms populations.