不同中性洗涤纤维与非纤维性碳水化合物比值饲粮对肉用绵羊甲烷排放的影响

本试验旨在研究不同中性洗涤纤维(NDF)与非纤维性碳水化合物(NFC)比值(NDF/NFC)饲粮对肉用绵羊甲烷排放的影响。试验采用4×4完全拉丁方试验设计,将16只杜泊×小尾寒羊杂交羯羊随机分成4组,每组4只,按维持水平饲喂NDF/NFC分别为3.02(饲粮1)、2.32(饲粮2)、1.58(饲粮3)、1.04(饲粮4)的全混合颗粒饲粮(玉米秸秆为粗饲料来源)。试验共进行4期,每期18 d,包括3 d的调整期、7 d的预试期和8 d的正试期,在正试期内测定甲烷产量、饲粮总能和营养物质表观消化率。结果表明:饲粮2的甲烷日排放量显著高于饲粮3和4(43.43 L/d vs.38.88和35.98 L/d;P0.05)。与饲粮1相比,饲粮2和3的每千克干物质采食量(DMI)甲烷排放量显著增加(38.00 L/kg DMI vs.42.24、41.69 L/kg DMI;P0.05),但是饲粮2、3和4之间差异不显著(P0.05)。随着NDF/NFC的降低,每千克可消化有机物(DOM)的甲烷排放量逐渐降低,饲粮4的每千克DOM的甲烷排放量显著低于饲粮1、2和3(58.78 L/kg DOM vs.75.00、73.35和64.11 L/kg DOM;P0.05)。随着NDF/NFC的降低,每千克中性洗涤纤维采食量(NDFI)或酸性洗涤纤维采食量(ADFI)的甲烷排放量逐渐增加,且各饲粮之间差异显著(P0.05)。综上所述,结合各营养物质表观消化率和甲烷排放效率,在维持水平下,采用NDF/NFC为1.04的玉米秸秆饲粮作为肉用绵羊甲烷减排的饲粮最合适。

Effects of Different Neutral Detergent Fiber/Nonfiberous Carbohydrate Diets on Methane Emission of Meat Sheep

This study investigated the effects of different neutral detergent fiber/nonfiberous carbohydrate (NDF/NFC) diets on methane emission of meat sheep.The trial was conducted according to a 4 ×4 Latin square design:16 Dorper×thin tailed Han crossbred wethers were randomly divided into 4 groups with 4 sheep each,and each group was randomly fed one of four total mixed pellet diets (corn stalk as the source of roughage) with the NDF/NFC of 3.02 (diet 1),2.32 (diet 2),1.58 (diet 3) and 1.04 (diet 4) at maintenance level,respectively.The trial included 4 periods with each lasted for 18 days,and the first 3 days of each period was an adjustment period,the following 7 days was a pretrial period and the last 8 days was an experimental period.Methane emission and the apparent digestibility of gross energy and nutrients of diets were measured in the experimental period.The results showed that the methane (CH4) daily emission of sheep fed the diet 2 was significantly higher than that of those fed diets 3 and 4 (43.43 L/d vs.38.88 and 35.98 L/d;P＜0.05).Compared with the sheep fed diet l,the methane emission of per kg dry matter intake (DMI) of sheep fed diets 2 and 3 was significantly increased (38.00 L/kg DMI vs.42.24 and 41.69 L/kg DMI;P＜0.05),but no significant difference was observed among sheep fed diets 2,3 and 4 (P＞0.05).With the NDF/NFC decrease,the methane emission of per kg digestible organic matter (DOM) was gradually decreased,and sheep fed the diet 4 was significantly lower than sheep fed diets 1,2 and 3 (58.78 L/kg DOM vs.75.00,73.35 and 64.11 L/kg DOM;P＜0.05).The methane emissions of neutral detergent fiber intake (NDFI) or acid detergent fiber intake (ADFI) were gradually increased with the NDF/NFC decrease,and the difference among sheep fed four diets was significant (P＜0.05).In summary,combining with the apparent digestibility of nutrients and methane emission efficiency,the corn stalk diet with NDF/NFC of 1.04 is suited as the formula of methane emission reduction.