| The objectives of this thesis were to study the effects of whole-crop wheat on in vitro rumen fermentation and nutrient digestion,blood parameters,rumen fermentation and microflora of Holstein bulls.Experiment 1.This experiment investigated the effects of whole-crop wheat hay(WCWH)on serum parameters,long-chain fatty acid,and rumen microbiome of Holstein bulls.In this study,twelve Holstein bulls[body weight(BW)= 485.0 ± 40.8 kg]were assigned to randomly 1 of 4 dietary treatments in a 4 x 4 Latin square design with 17 days of adaptation period and 5 days of collection period.Dietary treatments were four proportions of WCWH,0,33,67,and 100%(WCWH0,WCWH33,WCWH67,and WCWH 100,respectively).On the 18th and 22nd day during each experiment period,the blood and rumen content samples were collected for analyzing the serum biochemical indexes,long chain fatty acids,rumen long chain fatty acids microbes.Results from the study revealed no differences in the long-chain fatty acids(LCFA)proportion of rumen and serum(P>0.05).It was found that fed bulls with WCWH did not significantly affect the rumen microbial flora(P>0.05).Urea N concentration in the WCWH100 group was higher than that in the other groups(P<0.05).Experiment 2.This experiment was to investigate the effects of whole-crop wheat hay(WCWH)on nutrient apparent digestibility,plasma parameters,and ruminal fermentation.Experiment design and animal management were the same as Experiment 1.Blood samples were collected on the 18th day of each trial period,feed and faeces samples were collected for three days on the 19th-21 st days,and the rumen liquid of each cattle was collected on the 22nd day,then all the samples were brought back to the laboratory for sample testing.When the ratio of WCWH was greater than 33%,the nutritional intake of crude protein(CP)and higher apparent digestibility of ether extract(EE),organic matter(OM),and CP significantly increased(P<0.05).Urea N,NH3-N,isobutyrate and isovalerate levels increased with the increase in the proportion of WCWH(P<0.05).Experiment 3.The effects of whole-crop wheat hay(WCWH)on ruminal fermentation microbial communities.Experiment design and animal management were the same as Experiment 1.16S rRNA high-throughput sequencing analysis revealed similarities in the community composition,species diversity and relative abundance of dominant bacteria at the phylum and genus levels among the four groups(P>0.05).Experiment 4.Effects of different harvesting stages and time on rumen fermentation characteristics and microbial flora of whole crop wheat plant.The wheat harvested at different time(7:00 and 15:00)in different stage(milk stage and dough stage),treated in different way(hay and silage)were allocated in a 2×2×2 three factorial design.In this study,the whole crop wheat hay treatments can reduce the methane production in fermentation(P<0.05).The neutral detergent fiber degradation in the hay treatment harvesting at 7:00 were significantly higher than that in other treatments(P<0.05).Results from 16S rRNA high-throughput sequencing showed that the wheat silage harvesting at 7:00 in the milk-ripe stage group had greater microbial diversity and species richness(P<0.05).However,there were no differences in the relative abundance of dominant bacteria at the phylum and genus levels among treatments.Collectively,WCWH can improve the rumen fermentation and nutrient digestion.In vitro fermentation,the fermentation characteristics of wheat were influenced by harvesting stage,time and treatment way.However,its application in ruminants breeding has yet to be further explored in animal experiments. |
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