| This study used in vitro gas production and the nylon bag method to research the differences of forage digestibility between water buffalo and Jersey cow under the same feeding conditions. On this basis, the real-time PCR and 16s rRNA high-throughput sequencing technology were used to analyze the ruminal microbial community and population differences between buffalo and Jersey cows. Therefore, the purpose of this study was to clarify the effects of rumen microbial difference between the fiber digestion of buffalo and Jersey cow, then provide theoretical guidance for regulating ruminal fiber digestion of the water buffalo.Experiment one:The syringe in vitro gas production system was used to compare the digestibility differences of buffalo and Jersey cows on four forages, including cassava residue, corn silage, sugarcane residue silage, and elephant grass, under similar feeding situation. The results indicated that:(1) The gas production of cassava residue and corn silage of buffalo were higher than Jersey cow, but the gas production of sugarcane residue silage and elephant grass of buffalo were lower than Jersey cow. (2) The total volatile fatty acids in 24 h incubation fluid of cassava residue of buffalo were higher than that of Jersey cow, while the total volatile fatty acids in 24 h incubation fluid of sugarcane residue silage for buffalo were lower than Jersey. It was obvious that the buffalo and Jersey cow’s ruminal fluid in vitro digestion ability for the four forages have their own advantages.Experiment two:Nylon bag method with elephant grass as substrate was used to compare the ruminal digestibility differences between buffalo and Jersey cow under similar feeding situation. The results showed that: (1) The dry matter (DM), netural detergent fiber (NDF) and acid detergent fiber (ADF)’s slow degradation portion and degradable portion of elephant grass in buffalo were higher than that of jersey cow, and the DM, NDF’s rumen efficient digestibility of elephant grass have no difference between buffalo and jersey cow, while the ADF’s efficient digestibility in buffalo was higher than that of jersey cow. (2) The fast degradation portion and slow degradation portion of crude protein (CP) in the rumen was lower in buffalo than in Jersey cow, but the CP’s rumen efficient digestibility and degradable portion have no difference between buffalo and jersey cow. Therefore, this study indicated buffalo has higher digestibility for elephant fiber than jersey cow. Combined with the in vitro study results, which indicated the gas production of elephant grass for buffalo was lower than Jersey cow, so we supposed that the buffalo has higher nylon bag degradation rate for elephant grass fiber is related with its digestive physiology.Experiment three:This study compared ruminal fermentation parameters of buffalo and Jersey cows under similar feeding situation, and real-time PCR technique and 16s rRNA high-throughput sequencing technologies were used to compare their ruminal microbe community and quantity differences.The results of rumen fermentation parameters showed that:The total volatile fatty acid, acetate, propionate in the rumen of buffalo were significantly higher than that in Jersey cow, while the concentration of butyate, acetate/propionate in buffalo rumen were significantly lower than rumen of Jersey cow, the concentration of ruminal NH3-N was similar in the two species. The results of real-time PCR showed that:The population of bacteria, fungi, protozoa and selenomonas ruminantium in the rumen of buffalo were significantly higher than that in Jersey cow, however, the population of methanogen, ruminococcus albus, fibrobacter succinogenens and prevotella ruminicolano have no significant difference between the two species. The results of 16s rRNA high-throughput sequencing showed that:(1) In both buffalo and Jersey cow’s rumen, bacteroidetes and firmicutes were the predominant phyla, prevotellaceae was the predominant family, and the aboudance of bacteroidetes, prevotellaceae in buffalo rumen were significantly lower than that in rumen of Jersey cow, however, the aboundance of firmicutes was significantly higher in buffalo than Jersey cow. (2)The main methanogen genus in both buffalo and Jersey cow’s rumen is methanobrevibacter, and methanobrevibacter proportion in buffalo rumen was significantly lower than that in Jersey cow, while Rumen Cluster C proportion was significantly higher in buffalo rumen than that in Jersey cow. (3) Candida and Pichia was the predominant fungi genus in buffalo and Jersey cow’s rumen, respectively. Metadinium was the predominant protozoa genus in buffalo rumen, while, entodinium was the predominant protozoa genus in Jersey cow rumen. Therefore, under similar feeding situation, the rumen fermentation parameters, microbial quantity and community were different between rumen fluid of buffalo and Jersey cow, we can predicted that these differences can cause the forages digestibility difference between buffalo and Jersey cow’s ruminal fluid to some extent.Experiment four:The real-time PCR technique and 16s rRNA high-throughput sequencing technologies were used to study the ruminal microbe quantity and community difference after 24 h in vitro fermentation of four forages by buffalo and Jersey rumen fluid. The results of real-time PCR showed that:(1) The population of total bacteria and prevotella ruminicolano in 24 h incubation fluid of cassava residue for buffalo were higher than Jersey, while the population of total bacteria and prevotella ruminicolano in 24 h incubation fluid of corn silage, sugarcane residue silage and elephant grass were similar in the two species, and the prevotella ruminicolano in the three forage incubation fluid for buffalo were lower than Jersey cow. (2) The population of protozoa in 24 h incubation fluid of cassava residue, corn silage and elephant grass for Jersey was higher than buffalo, while the protozoa in 24 h incubation fluid of sugarcane residue silage for buffalo has no significant difference with Jersey cow. The population of fungi, methanogen, ruminococcus albus, fibrobacter succinogenens and selenomonas ruminantium in 24 h incubation fluid of four forages in buffalo have no difference with Jersey cow as well. In addition, the results of 16s rRNA high-throughput sequencing showed that:(1) Firmicutes was the predominant phyla and prevotellaceae was the predominant family in 24 h incubation fluid of four forages for Jersey cow, however, Firmicutes was the predominant phyla in 24 h incubation fluid of corn silage, elephant grass and sugarcane residue silage in buffalo, and prevotellaceae was the predominant family in 24 h incubation fluid of corn silage and elephant grass in buffalo. (2) Methanobrevibacter proportion in 24 h incubation fluid of the four forages for buffalo were higher than Jersey. (3) Incubation fluid of elephant grass, cassava residue and sugarcane residue silage for buffalo and Jersey have the same main fungi genus, were Neocallimastix, Candida and Pichia, respectively. Candida and neocallimastix was the predominant fungi genus in incubation fluid of corn silage for buffalo and Jersey cow, respectively. (4) Ostracodinium was the predominant protozoa genus in 24 h incubation fluid of elephant grass for buffalo and Jersey, but incubation fluid of three other forages for buffalo and Jersey have different main protozoa genus. Therefore, this study found that rumen microbial quantity and community were different in incubation fluid of same forages for buffalo and Jersey, and the rumen microbial population and community in in vitro fermentation liquid also significantly were affected by kinds of forages for the same species. Moreover, compared to the in vivo condition, the rumen microbial communtiy in 24 h incubation fluid was changed greatly. |
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