Impact of dietary Moringa oleifera leaves on intestinal pathogenic load and histological structure of growing rabbits raised under heat-stress conditions

Abstract

Forty-five growing New Zealand White (NZW) male rabbits weighed 750.0 ± 5.8 g aged 6 weeks were used in a feeding experiment lasting 56 days. Rabbits were housed in a semi-climatic chamber at a mean ambient temperature of 33.1°C and relative humidity of 43%. The rabbits were placed in three equal groups of five replicates. The first group was fed on free moringa diet (control, R1), while R2 and R3 groups were fed diets supplemented with 0.5% and 1.0% moringa dry leaves respectively. Daily feeds and water were offered ad libitum. At the end of the feeding period, three random animals of each group were slaughtered to investigate intestinal and caecal contents of pathogens and changes of intestinal and caecal tissues. The results indicated that there were no statistical differences among groups concerning daily feed intake, average daily gain and feed conversion ratio; however, slight improvement was noticed with rabbits fed R3. Intestinal microbial load, namely total plate count of Salmonella, Escherichia coli, Staphylococcus aureus, Clostridium perfringens and mould, was reduced (P < 0.01) with R2 and R3 diets compared with the control (R1). A similar trend was also noticed on caecal microbial load. Histological examination of jejunum tissues showed clear increases in villus height, villus : crypt ratio and obvious depth of caecal tunica mucosa, which might reveal better absorption of nutrients and microbial metabolites. It could be concluded that rabbits fed moringa-supplemented diets showed better feed conversion and intestinal and caecal histological structure, with clear reduction of gastro-intestinal pathogenic bacterial load under the hot climatic conditions.