不同生育期对‘118’饲草谷子青贮品质的影响

Effects of different growth periods on the quality of‘118’forage millet silage

为确定饲草谷子(Setaria italica)调制青贮的最适生育期,本研究采用随机区组设计,选用‘118’饲草谷子为供试品种,分别在其灌浆期、乳熟期和蜡熟期时收获,调制成小包装青贮饲料,厌氧发酵60 d后,对比其营养成分、发酵品质和微生物组成。结果表明:1)随着生育期的推进,青贮饲料中的干物质含量逐渐增加,然而粗蛋白质和可溶性碳水化合物含量呈降低趋势,乳熟期的可溶性碳水化合物含量较高。2)青贮后,乳酸菌的数量有所增加,其中乳熟期处理组数量最多,各处理组中均存在一定数量的霉菌、酵母菌和一般好氧性细菌。3)不同生育期的pH均较高,且乳酸含量偏低,但均未检测到丁酸的存在。4)利用隶属函数值法进行综合评价,结果表现为乳熟期>蜡熟期>灌浆期。虽然不同生育期的青贮品质存在差异,但青贮品质未达到高品质青贮饲料的标准。研究结果表明,外源添加青贮添加剂是改善饲草谷子青贮品质,减少营养物质损失的有效手段。

To determine the optimal growth period of forage millet(Setaria italica)silage,a random block design was adopted in this study,using‘118’forage millet varieties as test varieties.They were harvested during the filling period,milk maturity period,and wax maturity period to prepare small package silage.After 60 days of anaerobic fermentation,the nutrient composition,fermentation quality,and microbial composition were compared.The result showed that:1)As the growth period progressed,dry matter content in the silage gradually increased,while the crude protein content and soluble carbohydrate content showed a decreasing trend,and the soluble carbohydrate content in the milk maturity period was higher.2)After 60 days,the number of lactic acid bacteria in silage increased,with the highest number being observed in the treatment group in the milk maturity period.There were a certain number of molds,yeasts,and general aerobic bacteria in each treatment group.3)The pH value in different growth periods was relatively high and the lactic acid content was low,but the presence of butyric acid was not detected.4)The membership function value method was used for comprehensive evaluation,and the evaluation results were in the order:milk maturity>dough stage>filling period.Although there were differences in silage quality at different growth stages,it did not reach the standard of high-quality silage.The addition of exogenous silage additives was an effective means to improve the silage quality of forage millet and reduce nutrient loss.