基于蒸汽爆破的黄精茎秆饲料添加剂制备及其饲喂效果OA

[Objective]A feed additive derived from Polygonatum stems was prepared via steam explo-sion technology,and its effects on the lactation performance and immune function of dairy cows were investigated,providing a reference for the resource utilization of non-medicinal parts of Chinese medicinal herbs and the development of green feed additives.[Method]The Polygonatum stems were treated using instantaneous catapult steam explosion technology.Using alcohol-soluble total flavonoids and xylooligosaccharides as evaluation indicators,the effects of catalyst type,catalyst concentration,pressure,and residence time on the preparation of the Polygonatum stem feed additive were investi-gated.A 28-day feeding trial was conducted using 16 Holstein dairy cows,which were randomly divided into four groups(four cows per group):a control group(fed a basal diet),a 0.025%Polygo-natum stem group(basal diet supplemented with 0.025%mass fraction of Polygonatum stem feed additive),a 0.050%Polygonatum stem group(basal diet supplemented with 0.050%mass fraction of the additive),and a 0.075%Polygonatum stem group(basal diet supplemented with 0.075%mass fraction of the additive).The effects of the Polygonatum stem feed additive on dairy cow performance were evaluated based on production performance(milk yield),milk quality(somatic cell count,milk fat,milk protein,lactose,and non-fat milk solids),and serum immunoglobulin mass concentrations.[Result]Under the conditions of 0.10 mol·L-1 citric acid,a pressure of 1.4 MPa,and a residence time of 9 min,the xylooligosaccharide mass fraction in Polygonatum stems reached 47.7 g·kg-1,and the alcohol-soluble total flavonoid mass fraction reached 31.40 mg·g-1.The conversion rate of hemicel-lulose to xylooligosaccharides was 23.35%,and the extraction yield of alcohol-soluble total flavonoids was 8.58 times higher than that of untreated material.In the dairy cow feeding trial,compared with the control group,the 0.075%Polygonatum stem group showed a 70 kg increase in total milk yield corresponding to a 3.54%increase in milk yield.The 0.050%group exhibited a relatively stable low trend in somatic cell count,but the difference was not significant.The 0.075%group showed an improving trend in milk fat and non-fat milk solids,while the milk protein and lactose mass fractions were similar to those of the control group.Serum immunoglobulin mass concentrations were signifi-cantly increased in the 0.025%and 0.075%groups,whereas no obvious increase was observed in the 0.050%group which even showed a decreasing trend.[Conclusion]Citric acid-assisted steam explo-sion efficiently produced a Polygonatum stem feed additive rich in xylooligosaccharides and alcohol-soluble total flavonoids.Under the conditions of this feeding trial,the 0.075%additive showed a trend toward increasing milk yield and milk quality,while the immune function of dairy cows in the 0.025%and 0.075%groups significantly increased.