Digestion, growth performance and caecal fermentation in growing rabbits fed diets containing foliage of browse trees

Abstract

[EN] This study aimed to evaluate the effect of feeding dried foliage (leaves and petioles) of Acacia saligna, Leucaena leucocephala or Moringa oleifera on the performance, digestibility, N utilisation, caecal fermentation and microbial profiles in New Zealand White (NZW) rabbits. One hundred weaned male NZW rabbits weighing 819.2±16.6 g and aged 35±1 d were randomly allocated into 4 groups of 25 rabbits each. Rabbits were fed on pelleted diets containing 70% concentrate mixture and 30% Egyptian berseem (Trifolium alexandrinum) hay (Control diet) or one of the other 3 experimental diets, where 50% of berseem hay was replaced with A. saligna (AS), L. leucocephala (LL) or M. oleifera (MO). Compared to Control diet, decreases in dry matter (DM; P=0.004), organic matter (P=0.028), crude protein (CP; P=0.001), neutral detergent fibre (P=0.033) and acid detergent fibre (P=0.011) digestibility were observed with the AS diet. However, DM and CP digestibility were increased by 3% with the MO diet, and N utilisation was decreased (P<0.05) with AS. Rabbits fed AS and LL diets showed decreased (P=0.001) average daily gain by 39 and 7%, respectively vs. Control. Feed conversion was similar in Control and MO rabbits, whereas rabbits fed AS diet ate up to 45% more feed (P=0.002) than Control rabbits to gain one kg of body weight. Caecal ammonia-N was increased (P=0.002) with LL, while acetic acid was decreased (P=0.001) with AS diet vs. other treatments. Caecal E. coli and Lactobacillus spp. bacteria counts were decreased with MO by about 44 and 51%, respectively, vs. Control. In conclusion, under the study conditions, tree foliage from M. oleifera and L. leucocephala are suitable fibrous ingredients to be included up to 150 g/kg in the diets of growing rabbits, and can safely replace 50% of berseem hay in diets of NZW rabbits without any adverse effect on their growth performance. Foliage from M. oleifera had a better potential as a feed for rabbits than that from L. leucocephala. Although foliage from A. saliga may be also used at 150 g/kg in the diets of growing rabbits, this level of inclusion may result in reduced feed digestibility and growth performance.