PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

This study evaluated Leucaena leucocephala (LL) cultivars, Tarramba (TRB) and Wandergraze (WDZ), as a partial replacement for alfalfa to reduce feed cost in the tropics. The study examined the effects of varying inclusion rates of LL cultivars in feed pellets on in vitro fermentation and nutrient degradability. Caecal fermentation was evaluated over 96 hours using caecal content from male Hycole rabbits. Six LL-based dietary treatments partially replacing alfalfa with 10%, 15%, and 20% of either TRB or WDZ, and a CON diet were evaluated, and the volume of gas released was recorded. Results showed that the CON diet significantly produced higher net gas volume (60.22 ml/200 mg DM), in vitro organic and dry matter digestibility (76.71% and 73.58%) and metabolizable energy (11.79 MJ/kg) than the LL-based diets (p<0.05). Among the LL cultivars, WDZ 10% yielded the highest net gas volume (49.57 ml/200 mg DM), in vitro organic and dry matter digestibility (67.68% and 64.97% and), and energy content (10.78 MJ/kg DM) while TRB-based diets produced the lowest net gas volume (33.12-38.38 ml/200 mg DM) and metabolizable energy (7.53-8.82 MJ/kg DM). The potential gas volume was highest in CON (76.49 ml) and lowest in TRB10% group (54.78 ml) (p<0.05). In conclusion, WDZ 10% may represent an alternative forage resource for rabbits in high feed-cost regions, but performed less than an alfalfa-based diet in terms of fermentation and digestibility of nutrients. In vivo studies are recommended to examine the impacts of these cultivars on the production performance and overall health in rabbits.