Effects Of Different Quality Roughages And Concentrate To Roughage Rations On Nutrient Digestion And Rumen Microorganisms In Dairy Buffaloes

The number of buffaloes in China is as high as 27.431 million.It is an inevitable direction to develop both milk and meat after unloading the burden on the shoulders.But at present the dairy buffalo feeding management is extensive,the production level is low,the breeding benefit is not ideal,the number of stock is declining.In order to improve the production level of dairy buffaloes,lay the foundation for rational utilization of various feed resources and scientific feeding of dairy buffaloes,and improve the efficiency of dairy buffalo breeding,aiming at the current situation of dairy buffalo breeding,combined with research progress at domestic and abroad,In this study,two experimental systems were used to study the effects of different quality roughages and concentrate to roughage ration on digestion and metabolism of various nutrients,rumen fermentation parameters,rumen protozoa number,fungi and bacteria species and relative abundance of dairy buffalo reserve cattle.Experiment 1:Three Dehong buffaloes with permanent rumen fistulas,Mora and Nili-Rafi hybrid buffalo reserve cattle were fed 1 kg reserve concentrate supplement.According to 3×6 incomplete Latin square design,six kinds of roughages with different quality of alfalfa hay,oat hay,whole corn silage,sugarcane shoot silage,kinggrass fresh grass and straw hay were randomly selected for 6 periods of experiment.Experiment 2:After the end of experiment 1,3 fistulas continued to follow the incomplete Latin square design of 3×5,and were fed five diets with concentrate to roughage ratio of 20:80,35:65,50:50,65:35 and 80:20,respectively.Roughage consisted of oat hay,whole corn silage and straw hay,each accounting for 1/3 according to dry matter.Concentrate is the reserve cattle concentrate supplement.The pre-feeding period of each period was 12 d,and the feed intake of each feed was determined.13 to 15 days into the trial,at 90%of the free feed intake of feeding,digestion and metabolism of experiment was carried out by all muck method,accurate determination of each head of cattle feed feeding amount and fecal excretion,chemical composition analysis and collection of feed and fecal samples,in 15 d test in the morning after feeding 2 h was used to determine the rumen fermentation parameter acquisition tumor gastric fluid,rumen protozoon count,High throughput sequencing analysis of fungal ITS and bacterial 16S r RNA.The results show that:（1）Dry matter intake of alfalfa hay,oat hay,whole corn silage,sugarcane shoot silage,kinggrass fresh grass,straw hay and concentrate to roughage ratio of 20:80,35:65,50:50,65:35 and 80:20 were 1.75%,1.84%,2.12%,1.88%,1.54%and 1.21%of body weight respectively,1.41%,1.66%,1.72%,1.72%,1.72%.Dietary crude protein contents were 17.01%,8.71%,9.46%,10.58%,7.48%,6.67%,9.69%,12.15%,14.89%,17.52%,20.07%,respectively.Neutral detergent fiber content（NDF）was 38.37%,52.67%,46.38%,62.83%,66.38%,67.34%,51.71%,44.84%,36.92%,29.5%,22.21%,respectively.Non-fiber carbohydrate（NFC）contents were 36.27%,29.46%,36.76%,15.01%,18.67%,12.29%,29.11%,33.81%,39.43%,44.57%,49.68%,respectively.（2）To obtain the fitting equation of fecal output and feed intake,fecal output g/kg IDM（y）and nutrient intake g/d（x）per kg fecal DMprotein output per kg of fecal DM=0.0573 protein intake+49.619,R²=0.8723Fat excretion per kg of fecal DM=0.045 fat intake+6.271,R²=0.5434The CP and EE of DM were 49.61 g and 6.27 g per 1kg fecal excretion,respectively.（3）The apparent digestibility of dry matter（DM）in alfalfa hay,oat hay,whole corn silage,sugarcane shoot silage,king grass,straw hay and concentrate to roughage groups were 61.45%,61.31%,65.03%,54.07%and 58.99,respectively%,55.63%,53.19%,63.11%,64.32%,73.11%,74.78%.The estimation models of nutrient apparent digestibility were as follows:The true digestibility of CP in concentrate to roughage rations was-3.1601（ADICP/CP）+1.0084,R² was 0.7902The true digestibility of CP in 11 diets was 0.8836E-1.064（ADICP/CP）,R²=0.3622NDFn apparent digestibility=1-1.1016（ADL/NDFn）0.3408,R²=0.3898NFC apparent digestibility=0.4826 concentrate ratio+0.5657,R²=0.8803（4）pH from high to low were oat hay group,sugarcane shoot silage group,alfalfa hay group,straw hay group,Kinggrass fresh grass group,20:80 group,35:65 group,50:50 group,whole corn silage group,65:35 group,80:20 group.In whole corn silage group,rumen pH was lower than 6.4 and rumen fluid pH was lower than 6.2 in 80:20 diet with concentrate to roughage ratio higher than 50:50.Rumen pH decreased linearly with the increase of dietary starch content and NFC content:Rumen pH=-0.0208 starch content（%）+6.8804,R²=0.8559,Rumen pH=-0.015NFC content（%）+6.986,R²=0.5199.The rumen NH₃-N concentration in descending order was alfalfa hay group,80:20 group,65:35 group,King grass fresh grass group,50:50 group,whole corn silage group,35:65 group,sugarcane shoot silage group,20:80 group,oat hay group and straw hay group.The rumen NH₃-N concentration increased linearly with the increase of dietary protein content:Rumen NH₃-N concentration（mg/d L）=2.1586 dietary crude protein content（%）-4.8523,R²=0.8211The concentration of total volatile fatty acids（mmol/L）in rumen showed regular changes with dietary CP,NDF,NFC and NFC/NDF.The overall rule was the increase of dietary nutrient level.TVFA concentration=3.46CP%+43.85,R²=0.4305TVFA concentration=26.894（NFC/NDF）+63.743,R²=0.4806TVFA concentration=1.4394 NFC%+40.919,R²=0.5291TVFA concentration=-1.1879NDF%+142.13,R²=0.5513The proportion of acetic acid in TVFA increased with the increase of dietary NDF content.Acetic acid ratio=0.0012NDF%+0.641,R²=0.888.（5）The concentrate to roughage rations was 20:80,35:65,50:50,65:35 and 80:20,and the number of rumen protozoa was 7.98×105,5.80×105,3.78×105,3.55×105 and 2.36×105/m L,respectively.The number of protozoa decreased significantly with the increase of the proportion of concentrate supplement.（6）Fourteen Phylum,36 classes,70 orders,140 families,232 genera and 354 Species of fungi were detected in the rumen of dairy buffalo.Ascomycota and Basidiomyeota were mainly composed of Ascomycota and Basidiomyeota,with an abundance of 42.42%～99.43%and 0.39%～49.91%,respectively.Ascomycota dominated the roughage test group,with an abundance of more than 90%,which was much lower than that of concentrate to forage ratio test group.The relative abundance of Basidiomycota concentrate to roughage test group was much higher than that of roughage test group.Dairy buffaloes were fed 11 kinds of diets,and 62 types of fungi were significantly different in rumen.（7）There were 23 Phylum,38 classes,76 orders,123 families,288 genera and 346 Species of rumen bacteria detected in 33 rumen fluid samples from 11 diets and 3 cattle.The relative abundance of Bacteroidetes,Firmicutes and Spirochaetes ranged from 45.48%to 80.62%,13.94%to 48.44%and 0.24%to 4.31%,respectively.Bacteroidetes were mainly Prevotellaceae1 and Rikenellaceae,with the relative abundance of 7.8%～51.47%and 5.49%～16.62%,respectively.Firmicutes are mainly clostridia and Negativicutes,and the relative abundance of Firmicutes is 23.03%～24.06%and 1.39%-1.45%.The relative abundance of Treponema 2 in the phylum of spirochetes was0.91%～1.38%.The relative abundance of Bacteroidetes was higher in different quality roughage groups,and lower in different concentrate to roughage groups,in the range of 74.95～80.62%and 45.48%～71.54%,respectively,and decreased with the increase of concentrate level.The relative abundance of Firmicutes increased with the increase of concentrate to roughage ratio,from 25.35%to 48.44%.The relative range of different forage groups was 13.95%～16.46%,and the whole corn silage group was the highest.The relative abundance of Patescibacteria and Spirochaetes decreased with the increase of roughages quality and concentrate level.（8）Prevotella 1,Rikenellaceae RC9 Gut Group,Christensenellaceae R-7 Group,Prevotellaceae.The relative abundance of UCG-003 and Prevotellaceae UCG-001 ranged from 7.80%to 51.47%,5.49%to 16.62%,3.67%to 14.88%,1.2%to 5.1%and 0.32%to 2.6%,respectively.Dietary composition had an effect on the relative abundance of genus level.LEf Se analysis showed that there were 31 bacterial communities with significant differences among the 7groups:50:50 group,80:20 group,65:35 group,alfalfa hay group,whole corn silage group,kinggrass fresh grass group and straw hay group.（9）The abundance of Firmicutes in the core flora increased with the increase of concentrate to forage ratio.The abundance of Bacteroidetes decreased with the increase of concentrate to roughage ratio.When the ratio of concentrate is close to 0.7526,the abundance of the two is similar:Relative abundance of Bacteroidetes=-0.4605 concentrate ratio+0.8335,R²=0.9582Relative abundance of Firmicutes=0.4233 concentrate ratio+0.152,R²=0.959Relative abundance Spirochaetes=0.0007e^{4.156 concentrate ratio},R²=0.8175...