外源硒对饲用苎麻草产量和营养价值的影响

为了提高饲用苎麻营养价值,本研究采用随机区组设计,以苎麻饲用专用品种“中饲苎1号”为研究试材,通过两年大田试验和一年盆栽试验,土壤基施不同量亚硒酸钠(0、0.25、0.50、0.75和1.00 kg Se·hm^-2),研究外源硒对饲用苎麻草产量、粗蛋白、粗脂肪、粗灰分、中性洗涤纤维、酸性洗涤纤维、相对饲喂价值和营养元素硒(Se)、磷(P)、钾(K)及钙(Ca)含量的调控。结果表明,外源硒对饲用苎麻草产量无显著性影响,而对其营养价值有一定的影响,但变化幅度因施硒量、年份和刈割时间有所不同。与对照相比(0 kg Se·hm^-2),0.25、0.50、0.75和1.00 kg Se·hm^-2处理中2年大田试验平均粗蛋白含量分别提高1.52%、0.96%、-0.10%和-4.29%;粗脂肪含量分别下降0.25%、3.93%、1.54%和9.34%;粗灰分含量分别提高1.37%、1.23%、2.29%和0.85%;酸性洗涤纤维含量分别增加1.92%、2.15%、2.32%和3.22%;中性洗涤纤维含量变幅分别为-2.97%、-0.97%、2.01%和2.63%;相对饲喂价值变幅分别为1.74%、-0.103%、-3.14%和-4.30%;Ca含量变幅分别为0.07%、-2.01%、1.27%和-0.59%;P含量分别提高7.26%、7.68%、4.63%和4.54%;K含量分别变幅分别为4.59%、12.31%、-2.04%和2.83%;Se含量随着施硒量的增加逐渐增加,最高可达到2.07 mg·kg^-1。通过主成分分析结合模糊数学中隶属函数法综合评价表明,0.25~0.50 kg Se·hm^-2为该地区效果最佳施硒量,有利于提高饲用苎麻的营养价值。

Effects of exogenous selenium on grass yield and nutritive value of forage ramie

The aim of this study was to improve the nutritional value of forage ramie by providing optimal selenium (Se) nutrition. The effects of different Se doses on the grass yield and nutritive values of forage ramie were determined using the forage ramie cultivar “Zhongsizhu No1” as the experimental material. The experiments consisted of a pot experiment (1 year) and a field experiment (2 years) with a randomized block design. The doses of applied selenium were 0, 0.25, 0.50, 0.75, and 1.00 kg Se·ha^-1, applied as sodium selenite. We determined nutritive values including crude protein (CP), crude fat (CF), ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), and relative feeding value (RFV), and the contents of Se, phosphorus (P), potassium (K), and calcium (Ca). The results showed that exogenous Se had no significant effect on the grass production of forage ramie. Exogenous Se had some effects on nutritional values, but these effects varied depending on the Se dose, cutting time, and year. In the 2-year field experiment with Se doses of 0.25, 0.50, 0.75, and 1.00 kg Se·ha^-1, on average, crude protein content was increased by 1.52%, 0.96%, -0.10%, and -4.29%, respectively; crude fat content was decreased by 0.25%, 3.93%, 1.54%, and 9.34%, respectively; ADF content was increased by 1.92%, 2.15%, 2.32%, and 3.22%, respectively; crude ash content was increased by 1.37%, 1.23%, 2.29%, and 0.85%, respectively; the change in NDF content was -2.97%, -0.97%, 2.01%, and 2.63% respectively; the change in RFV content was 1.74%, -0.103%, -3.14%, and -4.30% respectively; the change in Ca content was 0.07%, -2.01%, 1.27%, and -0.59%, respectively; the change in P content was 7.26%, 7.68%, 4.63%, and 4.54%, respectively; and the change in K content was 4.59%, 12.31%, -2.04%, and 2.83%, respectively, compared with the control (0 kg Se·ha^-1). The Se content in forage ramie increased with increasing doses of applied Se, reaching a maximum of 2.07 mg·kg^-1. A comprehensive evaluation by principal component analysis combined with the membership function method showed that the range of 0.25-0.50 kg Se·ha^-1 was optimal for Se application in this region to improve the nutritional value of forage ramie.