3种饲草组合对湖羊瘤胃还原硝酸盐过程的影响

采用3×3拉丁方试验设计,研究以燕麦(Avena sativa)或苜蓿(Medicago sativa)干草等比例替代羊草(Leymus chinensis)后,对饲草中硝酸盐动态消失率及湖羊瘤胃发酵参数的影响。晨饲后0、1、2、3、4、5和6h通过瘤胃瘘管采集湖羊瘤胃液,测定瘤胃pH值以及硝酸盐(NO_3~-)、亚硝酸盐(NO_2~-)、氨态氮(NH_3-N)的浓度;同时,晨饲后2h经颈静脉采血测定血清高铁血红蛋白含量。结果表明,1)3组瘤胃液NO_3~-和NO_2~-浓度分别在喂后1和2h达到最大值,之后迅速降低;2)pH值、NO_3~-、NO_2~-浓度各组间均无显著差异(P0.05);NH_3-N仅在饲喂3h后全羊草组(A组)显著低于其它两组(P=0.018);3)高铁血红蛋白含量均较低,且无显著差异(P0.05)。本研究选用的牧草组合对湖羊瘤胃还原硝酸盐过程没有显著影响。

Effect of three grass combinations on the nitrate reduction in rumen fluid of Hu sheep

A 3 × 3 Latin square design was used to investigate the effect of feeding Leymus chinensis or equal proportion of alfalfa hay (Medicago sativa )and oat grass (Avena sativa )on dynamic changes of nitrate nitro-gen content and fermentation characteristics of Hu sheep.Rumen fluid was obtained at 0,1,2,3,4,5 and 6 h after feeding to determine the concentration of nitrate and nitrite and fermentation parameters.Blood samples were collected at 2 h after feeding to determine the blood methemoglobin content.The results showed that,1) the concentrations of nitrate and nitrite in rumen fluid increased to the maximum level at 1 and 2 h after feed-ing,respectively,and then decreased rapidly.2)There was no significant difference in the pH value and per-centage of nitrate and nitrite among groups (P >0.05);however,ammonia nitrogen (NH 3-N)concentration in group A was significantly lower than that in the other groups (P =0.018).3)All the groups had a low concen-tration of blood methemoglobin,and no significant difference was observed among them (P >0.05).In conclu-sion,different grass combination in this study had no effect on nitrate reduction process in the rumen of Hu sheep.