Comparison Of Outflow Rate, In Vitro Fermentation And Bacterial Flora Of The First Compartment In Alpaca And Sheep

1 Comparison of outflow rate of the first compartment in alpaca and sheepThe experiment was conducted to determine the passage rate of solid particles, measured by faecal Cr, and fluids measured by either faecal Co or disappearance of Co from the first compartment in alpaca and sheep. Three heathy male alpacas [(27.0±4.6) kg] and Jinzhong sheep [(26.2±2.7) kg] were selected. The results showed as follows:estimated by multicompartmental model, solid passage rate k1 showed a decreasing tendency (P=0.072) and solid passage rate k2 was significantly lower (P<0.01) in alpaca (3.44%/h and 16.90%/h) in comparison to sheep (4.32%/h and 35.06%/h). There was no significant difference (P>0.05) to solid passage rate k estimated by exponential model between alpaca (5.13%/h) and sheep (5.14%/h). The MRT value of alpaca was higher than sheep in both models. No significant difference (P>0.05) was recorded, to fluid passage rate k estimated by Gamma4 model (faecal Co) and exponential model (Co disappearance from the rumen), between alpaca (6.21%/h and 7.73%/h) and sheep (7.02%/h and 8.43%/h). The volume and out follow of the first compartment were significantly lower (P<0.05) in alpaca (6.23 L and 0.44 L/h) than that in sheep (10.69 L and 0.90 L/h).It would be conclude that gastrointestinal retention time of digesta in alpaca is longer than sheep, this difference can partly explain the reason that alpaca has a higher roughage digestion rate.2 Comparison of in vitro fermentation of the first compartment microbes in alpaca and sheepIn vitro formation with cron straw as substrates was used to investigate the effects of different concentrate to roughage ratios (C:R=3:7,5:5,7:3) diets on the culture fluid pH, gas production and DM degradation. Microorganism was sampled from the first compartment of six alpacas and six sheep which were assigned in a 3 x 3 Latin square. The results showed that:The pH didn’t show significant difference with different diets of both animal (P>0.05), the pH of alpaca was lower than that of sheep with same diets [C:R=3:7 (P<0.05),5:5 (P<0.05) or 7:3 (P=0.069)]. All the pH is in the range of 6.6～6.8. The gas production and DM degradation didn’t show significant difference (P>0.05) with same diet between alpaca and sheep or different diets of same animal. Collectively, these results indicated that microorganisms in the first compartment of alpaca could produce more VFA than that in sheep when using in vitro formation with cron straw as substrates, which could explain why alpaca has higher energy efficiency, and have stronger ability to degrade poor quality forage.3 Comparison of microbial flora of the first compartment in alpaca and sheepTo investigate the effects of different concentrate to roughage ratios (C:R=3:7,5:5,7:3) diets on changes of bacterial community in the first compartment of alpaca and sheep, roll tube methods and the bar-coded 454-pyrosequencing strategy was applied.The results of roll tube method showed that the number of total bacteria and amylolytic bacteria in the first compartment of alpaca was significantly (P<0.05) less and the number of cellulolytic bacteria was significantly (P<0.05) higher than that of sheep with the diet 30% concentrate, there was no significantly (P>0.05) difference of the number of total bacteria, amylolytic bacteria and cellulolytic bacteria with the diet of 50% and 70% concentrate; the number of total bacteria, amylolytic bacteria and cellulolytic bacteria between different concentrate to roughage ratios diets of same animal shows no significantly difference (P>0.05). This study shows that alpaca has stronger ability of plant fiber digestion than sheep when using the diet of high ratio of low quality forage.The results of pyrosequencing techniques suggested that bacterial community is more complex in the first compartment of alpaca than that in sheep. Animal species and diet structure can significantly influence the bacterial community in the first compartment. Bacteroidetes and Firmicutes were the dominant phylum in the first compartment of alpaca and sheep, and representing more than 90% of the total sequence. Methanobrevibacter was the dominant methanogen genus in the alpaca and sheep. Prevotella as the the most abundant genus in alpaca and sheep, was decreased (P<0.05) when the proportion of concentrate increased. Related to the fiber degradation, relative abundance of Clostridium XlVa in alpaca was higher (P<0.05) than that in sheep with the diet of 50% and 70% concentrate. Proteobacteria had an increasing tendency (P=0.081) in alpaca than that in sheep with the diet of 30% concentrate. When the concentrate to roughage ratio was 7:3, relative abundance of Butyrivibrio in alpaca was higher (P<0.05) than that in sheep, and relative abundance of Methanobrevibacter in sheep very significantly (P<0.01) higher than that in sheep with diet of other roughage ratios and alpaca with diet of all concentrate to roughage ratios.Taken together, this study shows that alpaca had a more complex bacterial community in its first compartment, could easily resist low quality roughage, could make better use of forage with high fiber content, and had low methane emission with diet of high roughage ratio.