Ruminants are herbivores evolved to utilise fibre - rich roughage feeds. The compartmental stomach holds feed and provides the requirements for the vast and diverse microbial population it hosts, and in return the microbial population ferment fibrous feeds and produce volatile fatty acids, which are by-products of the microbes but a vital energy source for the host animal. However, under intensive management, ruminants including camels are fed starch rich diets in order to meet the increasing energy requirements and performance improvements. Risk of acidosis and laminitis is high under this type of management, which have an implication on the animal health and performance.
In this study the bacterial diversity of the Arabian camel (Camelus dromedarius) gastro-intestinal tract, and in particular the lactic acid producing bacteria (LAB), lactic acid utilizing bacteria (LUB), and cellulolytic bacteria (CB) was investigated using cultural dependent techniques. Identification of the purified bacterial isolates of the different types was based on the near complete sequence of the respective 16S rRNA gene. Protozoa! types and counts were also carried out. In addition, an experiment was carried out to monitor selected bacterial isolates during dietary manipulation, using real time PCR. Gastrointestinal tract samples for the different experiments were obtained from either the Meramist Pty Ltd abattoir in Caboolture QLD immediately after slaughter or from camels fitted with permanent rumen cannulae. These animals were used at either the UQ Gatton campus or the Al-Ain Animal Farm, The Faculty of Food Systems, United Arab Emirates University.
Culturing, enumeration, isolation, and morphological and biochemical characterisation of bacteria was carried out at the gut microbiology laboratory, School of Animal Studies, UQ Gatton and identification of bacteria and real time PCR analysis was carried out at the molecular biology laboratory, School of Agronomy and Horticulture, UQ Gatton. Rumen samples for protozoal counts and identification were obtained from the fistulated camels kept at the Al-Ain Animal Farm in UAE. Camels in the dietary manipulation experiment were either adapted to Rhodes grass or Rhodes grass + steam flaked barley grain (40: 60 ratio) in a 2 x 4 crossover design experiment (2 diets, 4 animals). Tue DNA was extracted from ruminal samples at Al-Ain Animal Fann and transferred to Australia for further real time PCR analysis.
Following a roughage diet the number of total anaerobic bacteria in the camel rumen was found to be 1.7 x 108 cfu/ml. Lactic acid producing bacteria represented 18.5% and the cellulolytic bacteria represent 15.8% of the total counts. Shifting camels to a grain diet resulted in an increase in the total bacteria, LAB and CB by 4.6, 28 and 3 fold respectively, but the relative proportion of cellulolytic bacteria decreased. Supplementary feeding of Rhodes grass fed camels with steam-flaked barley decreased (P<0.05) the numbers of protozoa and the rumen pH…………………….