微量元素添加模式对肉鸡生长性能、微量元素代谢和血浆抗氧化性能的影响

本试验旨在研究不同微量元素添加模式对肉鸡生长性能、微量元素代谢和血浆抗氧化性能的影响。选取720羽1日龄科宝(Cobb-500)肉鸡,随机分为4个组,每个组10个重复,每个重复18只鸡。行业标准组:按照农业行业标准NY/T 33—2004添加铜、铁、锌和锰。NRC标准组:按照NRC(1994)推荐量添加铜、铁、锌和锰。NRC比例组:实测基础饲粮中铜、铁、锌、锰的含量,以过量最多的铜(相对于NRC标准)的倍数补齐其余3种元素。相对生物学效价组:假设基础饲粮中微量元素的生物学利用率为额外添加硫酸盐的30%,对其含量进行校准后按照NRC比例组的方法添加。微量元素都以硫酸盐形式添加,试验期42 d。结果表明:1)不同微量元素添加模式未对肉鸡生长性能和死亡率造成显著差异(P0.05)。2)21日龄时,NRC比例组肉鸡十二指肠铜转运蛋白1(Ctr1)的mRNA相对表达量显著高于其余各组(P0.05),NRC比例组和相对生物学效价组肉鸡十二指肠二价金属转运蛋白1(DMT1)的mRNA相对表达量显著高于其余2组(P0.05);42日龄时,NRC标准组和相对生物学效价组肉鸡十二指肠DMT1的mRNA相对表达量显著高于其余2组(P0.05);各组间21和42日龄肉鸡十二指肠锌转运蛋白1(Zn T1)和锌转运蛋白5(Zn T5)的mRNA相对表达量没有显著差异(P0.05)。3)21日龄时,NRC比例组和相对生物学效价组肉鸡血浆总抗氧化能力(T-AOC)显著高于其余2组(P0.05);42日龄时,与相对生物学效价组相比,NRC比例组肉鸡血浆过氧化氢酶(CAT)活性显著下降(P0.05)。4)粪便中微量元素浓度和饲粮的微量元素添加浓度存在显著的正相关关系(P0.05)。由此可见,从微量元素吸收效率和肉鸡血浆抗氧化性能来看,考虑基础饲粮微量元素相对生物学效价并按NRC比例添加是更适宜的添加模式,同时减少了粪便中微量元素的排泄。

Effects of Supplemental Patterns of Trace Minerals on Growth Performance,Trace Mineral Metabolism and Plasma Antioxidant Ability in Broilers

This experiment was conducted to determine the effects of different supplemental patterns of trace minerals on growth performance, trace mineral metabolism and plasma antioxidant ability in broilers. A total of 720 one?day?old Cobb 500 broilers were randomly assigned to 4 groups, each group contained 10 replicates with 18 broilers per replicate. Industrial standard group: dietary copper ( Cu) , ferrum ( Fe) , zinc ( Zn) and manganese ( Mn) were added according to agriculture industrial standards NY/T 33—2004. NRC standard group: dietary Cu, Fe, Zn and Mn were added following NRC ( 1994 ) recommendation. NRC proportion group: after measurement of mineral content in basal diet, the highest multiple of Cu in basal diet to NRC rec?ommendation was found, and then the rest of minerals were supplemented to reach same multiple. Relative bio?availability group: bioavailability of minerals in feed ingredients was assumed 30% relative to sulfates, and then practical contents were transformed into valid content of equivalent sulfate. Finally, adding sulfates as NRC proportion group. Trace minerals were provided as inorganic sulfates. The experiment lasted for 42 days. The results showed as follows: 1 ) different supplemental patterns of trace minerals did not cause significant differences on growth performance and mortality rate of broilers ( P>0.05) . 2) At 21 days of age, the relative mRNA expression of copper transporter 1 ( Ctr1) in duodenum of broilers in NRC proportion group was signif?icantly higher than that in other groups ( P<0.05); the relative mRNA expression of divalent metal ion trans?porter 1 ( DMT1) in duodenum of broilers in NRC proportion group and relative bioavailability group was sig?nificantly higher than that in other groups (P<0.05). At 42 days of age, the relative mRNA expression of DMT1 in duodenum of broilers in NRC standard group and relative bioavailability group was significantly high?er than that in other groups ( P<0.05) . There were no significant differences on the relative mRNA expression of zinc transporter 1 ( ZnT1) and zinc transporter 5 ( ZnT5) among all groups at 21 and 42 days of age ( P>0.05) . 3) The plasma total antioxidant capacity ( T?AOC) of broilers in NRC proportion group and relative bioavailability group was significantly higher than that in other groups at 21 day of age (P<0.05), while the plasma catalase ( CAT) activity of broiler in NRC proportion was significantly lower than that in telative bio?availability group at 42 day of age ( P<0.05) . 4) Positive correlation between fecal trace minerals concentra?tion and dietary supplemental concentration of trace minerals was observed ( P<0.05) . In conclusion, from the perspective of absorption efficiency and plasma antioxidant ability, programme considering relative bioavail?ability of trace minerals in basal diet is optimum, meanwhile, it reduce mineral excretion.