紫玉米秸秆青贮饲料对热应激奶山羊能量利用、血浆代谢和抗氧化参数的影响

试验采用4×4拉丁方试验设计，选取8只体况良好的经产萨能奶山羊（体重，41.50±1.84 kg；平均数±标准差）随机分为4组，四种日粮处理分别为（粗饲料均占日粮干物质50%）：粗饲料为稻草组（NC）、粘玉米秸秆青贮饲料组（PC1）、粘玉米秸秆青贮饲料+1 g/d商业紫玉米花青素提取物组（PC2）及紫玉米秸秆青贮饲料组（AR）。每期试验周期持续21 d，其中最后7 d为样品采集期。结果表明：1）羊舍平均温度、湿度与温湿指数分别为30.54°C、72.66%及82.28。2）粘玉米和紫玉米秸秆青贮饲料蛋白和能量价值参数差异均不显著（P>0.05）。3）NC组显示较低水平（P<0.05）的消化能、代谢能、总能表观消化能与总能利用率；AR组消化能利用率显著（P<0.05）高于其他组。4）NC组葡萄糖显著（P<0.05）低于PC2组和AR组；但尿素氮显著（P<0.05）高于其他组。5）PC2与AR组谷胱甘肽S-转移酶显著（P<0.05）高于NC和PC1组；PC2与AR组丙二醛显著（P<0.05）低于NC和PC1组。由此可见，紫玉米秸秆青贮饲料可提高热应激奶山羊的消化能利用率，改善能量利用；对血浆代谢参数无副作用影响，但可提升抗氧化参数，有缓解奶山羊热应激的潜力。

Effect of purple corn stover silage on energy utilization, plasma metabolites and antioxidant capacity parameters of heat-stressed dairy goats

The experiment was conducted using eight healthy multiparous Saanen dairy goats (body weight, 41.50±1.84 kg; mean±standard deviation) with a double 4×4 Latin square design. The four treatments were as follows (the ratio of concentrate to roughage for all diets was 50:50): roughage was rice straw (NC), sticky corn stover silage (PC1), PC1+1 g/d purple corn pigment (PC2), and anthocyanin-rich purple corn stover silage (AR), respectively. The treatment period was 21 d (14-d adaptation to new diet; and 7 d sampling). The results showed that: 1) the average temperature, humidity and temperature humidity index were 30.54°C, 72.66% and 82.28, respectively. 2) There was no significant difference (P>0.05) in the protein and energy value parameters between SSS and PSS. 2) Compared with the other groups, NC group showed lower (P<0.05) levels of digestive energy (DE), metabolizable energy (ME), digestibility of gross energy, and availability of gross energy; and availability of DE in AR group was significantly higher (P<0.05) than that of the remaining groups. 3) Goats receiving the NC tended to (P<0.05) reduce plasma glucose compared to PC2 and AR groups, whereas it could increase plasma urea nitrogen relative to other groups. 4) The concentrations of glutathione S-transferase and malondialdehyde in PC2 and AR groups were significantly higher (P<0.05) and significantly lower (P<0.05) than that of the NC and PC1 groups, respectively. In was concluded that PSS had the potential to increase ME/DE, improving energy utilization; as well as it had no side effects on plasma metabolites, whereas it could improve the antioxidant capacity parameters of heat stressed dairy goats to help alleviate heat stress.