دانلود رایگان مقاله تجزیه و تحلیل تنوع باکتریایی شکمبه بز در طول تغییر رژیم غذایی

Abstract

High-grain feeding used in the animal production is known to affect the host rumen bacterial community, but our understanding of consequent changes in goats is limited. This study was therefore aimed to evaluate bacterial population dynamics during 20 days adaptation of 4 ruminally cannulated goats to the high-grain diet (grain: hay – ratio of 40:60). The dietary transition of goats from the forage to the high-grain-diet resulted in the significant decrease of rumen fluid pH, which was however still higher than value established for acute or subacute ruminal acidosis was not diagnosed in studied animals. DGGE analysis demonstrated distinct ruminal microbial populations in hay-fed and grain-fed animals, but the substantial animal-to-animal variation were detected. Quantitative PCR showed for grain-fed animals significantly higher number of bacteria belonging to Clostridium leptum group at 10 days after the incorporation of corn into the diet and significantly lower concentration of bacteria belonging to Actinobacteria phylum at the day 20 after dietary change. Taxonomic distribution analysed by NGS at day 20 revealed the similar prevalence of the phyla Firmicutes and Bacteroidetes in all goats, significantly higher presence of the unclassified genus of groups of Bacteroidales and Ruminococcaceae in grain-fed animals and significantly higher presence the genus Prevotella and Butyrivibrio in the forage-fed animals. The three different culture-independent methods used in this study show that high proportion of concentrate in goat diet does not induce any serious disturbance of their rumen ecosystem and indicate the good adaptive response of caprine ruminal bacteria to incorporation of corn into the diet.

5. Conclusion In summary, data of the present study demonstrated that the dietary transition of goats from a forage-to a high-grain-diet resulted in the decrease of rumen fluid pH, which was however still higher than value established for subacute ruminal acidosis indicating that the abrupt change in diet did not cause the ruminal acidosis as clinical pathological entity. The three different cultureindependent methods used to describe the dietary influence on the caprine rumen bacterial diversity and quantity indicated the significant changes, but also the core microbiome stability. DGGE analysis showed the substantial animal-to-animal variation, but the clustering of the bacterial communities with respect to diets was evident. NGS analysis resulted in the very high number of uncultured bacteria, in the relatively stable proportion of the Firmicutes and Bacteroidetes found as the most dominant phyla and in the genus level differences mostly profound in the groups of unclassi- fied Bacteroidales and Ruminococcaceae increased in the concentrate-fed goats and in the Prevotella and Butyrivibrio increased in the forage-fed goats. High proportion of corn in goat diet however did not induce any serious disturbance of the ruminal bacterial ecosystem.