反刍动物对铜(Cu)的表观吸收较低,在典型的进料条件下,从氧化铜(CuO)等来源吸收0.01至0.07g/g,导致高水平的排泄。提高铜的生物利用度可以减少维持铜状态所需的补充量,减少排泄。特别是在存在膳食拮抗剂如硫(S)和钼(Mo)的情况下。我们研究的目的是确定饲喂用Lys包被的纳米颗粒CuO时奶牛的Cu状态,与不饲喂或与饲喂奶牛日粮中Cu吸收拮抗剂(S和Mo)的常规CuO相比。在2×2析因设计中使用了56头多胎荷斯坦-弗里斯母牛,它们在产牛后48d±17.4(平均值±SD),产奶40.6±6.9kg/d。4个治疗组;CuO(O-),CuO与添加的拮抗剂(O+),纳米CuO与赖氨酸涂层(N-),和纳米CuO与添加拮抗剂(N+)的Lys涂层,喂养16周。我们制定的饮食含有约17毫克铜/公斤干物质(DM)和饮食拮抗剂含有额外的1克S/公斤DM和6毫克Mo/公斤DM,将Lys添加到O-和O+中,以提供与N-和N+相同的每日供应量。在第0、2、4、6、10和16周收集血液样品,在第0和16周收集肝活检样品。我们发现饮食治疗对DM摄入量没有影响,牛奶产量,活体重或身体状况评分,平均值为23.3kg/d,40.1kg/d,646kg和2.68,但常规饲喂的奶牛的牛奶SCC高于非CuO,或添加拮抗剂。我们还发现治疗对γ-谷氨酰转移酶的血液活性没有影响,超氧化物歧化酶或铜蓝蛋白,血液学概况,或血浆铜和铁的浓度。我们发现,饲喂O-或N-的奶牛的血浆Mo浓度从0.36µmol/L增加到接受O或N的奶牛的0.80µmol/L。在研究期间,其他饮食拮抗剂还将饲喂常规CuO(C)的奶牛肝脏中的Cu浓度降低了1.3mg/kgDM/d,但在饲喂饮食拮抗剂和涂有Lys(N+)的纳米CuO的奶牛中,肝脏Cu浓度增加1.1mg/kgDM/d。我们的研究首次证明,在奶牛存在饮食拮抗剂的情况下,用赖氨酸涂层将CuO的粒径降低到纳米级可以提高CuO的生物利用度,我们没有观察到对性能或健康的任何负面影响。
The apparent absorption of copper (Cu) in ruminants is low, with between 0.01 and 0.07 g/g absorbed from sources such as copper oxide (CuO) under typical feeding conditions, resulting in high levels of excretion. Improving the bioavailability of Cu could reduce the supplemental amount required to maintain Cu status and reduce excretion, particularly in the presence of dietary
antagonists such as sulfur (S) and molybdenum (Mo). The objective of our study was to determine the Cu status of cows when fed nanoparticle CuO coated with Lys compared with conventional CuO when fed without or in combination with antagonists to Cu absorption (S and Mo) in the diet of dairy cows. Fifty-six multiparous Holstein-Friesian cows that were 48 d ± 17.4 (mean ± SD) post calving and yielding 40.6 ± 6.9 kg milk/d were used in a 2 × 2 factorial design. The 4 treatment groups were; CuO (O-), CuO with added
antagonists (O+), nano CuO with a lysine coating (N-), and nano CuO with a Lys coating with added
antagonists (N+), fed for 16 wks. We formulated the diets to contain approximately 17 mg Cu/kg dry matter (DM) and diets with
antagonists contained an additional 1 g S/kg DM and 6 mg Mo/kg DM, with Lys added to O- and O+ to provide the same daily supply as N- and N+. Blood samples were collected at wk 0, 2, 4, 6, 10 and 16, and liver biopsy samples at wk 0 and 16. We found no effect of dietary treatment on DM intake, milk yield, live weight or body condition score, with mean values of 23.3 kg/d, 40.1 kg/d, 646 kg and 2.68, but milk SCC was higher in cows fed conventional compared with non CuO, or with added antagonist. We also found no effect of treatment on blood activity of gamma glutamyl transferase, superoxide dismutase or ceruloplasmin, hematology profile, or plasma Cu and iron concentration. We found that plasma Mo concentration was increased from 0.36 µmol/L in cows fed O- or N- to 0.80 µmol/L in those receiving O+ or N+. Additional dietary antagonists also decreased the concentration of Cu in the liver of cows fed conventional CuO (C+) over the study period by 1.3 mg/kg DM/d, but in cows fed dietary
antagonists and nano CuO coated with Lys (N+), liver Cu concentration was increased by 1.1 mg/kg DM/d. Our study is the first to demonstrate that reducing the particle size of CuO into the nano scale with a lysine coating improves the bioavailability of CuO in the presence of dietary antagonists in dairy cattle, and we did not observe any negative effects on performance or health.