Ruminal parameters and ruminal degradability of feedlot sheep fed safflower grains

SUMMARY This study aimed to evaluate the rumen degradability of dry matter (DM), disappearance of neutral detergent fiber (NDF) of Tifton 85 hay, and fermentation parameters (pH and ruminal ammonia nitrogen) of sheep fed diets with inclusion of safflower grains (0, 7.50 and 15%). Three mixed breed lambs with average body weight of 35.50± 1.50 kg were used. The rumen degradability of dry matter and NDF of the Tifton 85 haywas analyzedby the disappearance of DM and NDF, and the kinetic parameters adjusted according to the first order asymptotic model. The samples were incubated in the rumen in descending order (96, 48, 24, 12, 6, 3, 0 hours). The determination of ruminal pH and ruminal ammonia nitrogen (RAN) was performed before feeding and 2, 4, 6 and 8 hours after feeding. Data of ruminal fermentation were tested by analysis of variance with repeated measures in time, at 5% probability. Ruminal pH values were not statistically different. When evaluating the RAN, there was a significant difference between the times and treatments for the diet with 15% safflower. The diets presented low effective degradability of DM and NDF with mean values of 18.02% and 47.40%, respectively. The safflower grain can be used up to 7.50% in the diets without altering the degradability and ruminal fermentation.

摘要
本研究旨在评估饲喂添加红花籽（添加量分别为0、7.50%和15%）日粮的绵羊的提夫顿85干草（Tifton 85 hay）干物质（DM）瘤胃降解率、中性洗涤纤维（NDF）消失率，以及瘤胃发酵参数（pH值与瘤胃氨氮（RAN））。本试验选用平均体重为35.50±1.50 kg的杂交肉羊羔羊3只。通过干物质与中性洗涤纤维的消失率，结合一级渐近模型拟合动力学参数，对提夫顿85干草的干物质及NDF瘤胃降解率进行分析。样本在瘤胃内的孵育时长按降序依次设置为96、48、24、12、6、3、0小时。分别于饲喂前及饲喂后2、4、6、8小时测定瘤胃pH值与瘤胃氨氮（RAN）含量。采用5%显著性水平的时间重复测量方差分析对瘤胃发酵数据进行统计检验。各组瘤胃pH值无统计学显著差异。在评估瘤胃氨氮指标时，15%红花籽日粮组的不同采样时间与日粮处理间存在显著差异。各试验日粮的干物质与中性洗涤纤维有效降解率均较低，均值分别为18.02%与47.40%。日粮中红花籽的添加量最高可达7.50%，且不会改变饲料的瘤胃降解特性与瘤胃发酵状态。