不同产地燕麦干草常规营养成分及体外发酵参数的比较

Comparison of conventional nutrient composition and in vitro fermentation parameters of oat hay in different producing areas

为了比较不同产地燕麦干草的常规营养成分和体外发酵参数,试验以产地为单位将采集的燕麦干草分为3组(宁夏组、甘肃组和澳大利亚组),首先每组随机取10份样品测定常规营养成分[中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)、粗蛋白(CP)、粗脂肪(EE)、粗灰分(Ash)、钙(Ca)、磷(P)、非纤维性碳水化合物(NFC)]含量;然后每组随机取6份样品使用人工瘤胃装置进行体外发酵试验,于体外发酵2,4,6,8,10,12,16,20,24,30,36,48 h后测定产气量,于48 h后采集发酵液,测定体外发酵参数(pH值,氨态氮含量,总挥发性脂肪酸、乙酸、丙酸和丁酸浓度)。结果表明:NDF、CP和EE含量均为宁夏组最高,甘肃组居中,澳大利亚组最低;ADF、ADL、Ash、Ca和P含量均为甘肃组最高,宁夏组居中,澳大利亚组最低;NFC含量为澳大利亚组最高,甘肃组居中,宁夏组最低。体外发酵时间2,4,6,8,10,12 h的产气量均为澳大利亚组最高,甘肃组居中,宁夏组最低;体外发酵时间为16,20,24,30,36,48 h的产气量均为澳大利亚组最高,宁夏组居中,甘肃组最低。体外发酵48 h后,宁夏组和甘肃组pH值相近,二者略高于澳大利亚组,但各组pH值均差异不显著(P>0.05);宁夏组和甘肃组氨态氮含量显著高于澳大利亚组(P<0.01),但宁夏组和甘肃组差异不显著(P>0.05)。与宁夏组和甘肃组相比,澳大利亚组的总挥发性脂肪酸浓度分别增加了7.95%和12.20%,乙酸浓度分别增加5.11%和10.38%,丙酸浓度分别增加16.50%和21.53%,丁酸浓度分别增加15.50%和2.29%,但各组间均差异不显著(P>0.05)。说明甘肃和宁夏产燕麦干草的瘤胃降解特性较为相似,二者与澳大利亚产燕麦干草的差异较大。

In order to compare the conventional nutrient composition and in vitro fermentation parameters of oat hay from different producing areas,the oat hay from Ningxia,Gansu and Australia were collected in this experiment,and were divided into three groups(Ningxia group,Gansu group and Australia group)according to producing area.Firstly,the conventional nutrients(the content of neutral detergent fiber[NDF],acid detergent fiber[ADF],acid detergent lignin[ADL],crude protein[CP],crude fat[EE],crude Ash[Ash],calcium[Ca],phosphorus[P],non-fibrous carbohydrate[NFC])of oat hay were measured in each group with 10 random samples.Then,the in vitro fermentation tests was carried out by artificial rumen apparatus in each group with 6 random samples.Gas production was measured after 2,4,6,8,10,12,16,20,24,30,36 and 48 h of the fermentation in vitro,and fermentation liquid was collected to determine fermentation parameters(pH value,ammonia nitrogen content,total volatile fatty acids,acetic acid,propionic acid and butyric acid concentrations)in vitro after 48 h.The results showed that the contents of NDF,CP and EE were the highest in Ningxia group,the middle in Gansu group,and the lowest in Australia group.The contents of ADF,ADL,Ash,Ca and P were the highest in Gansu group,the middle in Ningxia group,and the lowest in Australia group.The NFC content was the highest in Australia group,the middle in Gansu group,and the lowest in Ningxia group.When the in vitro fermentation time was 2,4,6,8,10 and 12 h,the gas production was the highest in Australia group,the middle in Gansu group,and the lowest in Ningxia group.When the in vitro fermentation time was 16,20,24,30,36 and 48 h,the gas production was the highest in the Australian group,the middle in the Ningxia group and the lowest in the Gansu group.After 48 h in vitro fermentation,the pH values of in vitro fermentation in the Ningxia group and the Gansu group were similar,which were slightly higher than that in Australia group,but there was no significant difference in pH values among all groups(P>0.05).The ammonia nitrogen content in Ningxia group and Gansu group was significantly higher than that in Australia group(P<0.01),but there was no significant difference between Ningxia group and Gansu group(P>0.05).Compared with Ningxia group and Gansu group,total volatile fatty acid concentration in Australia group increased by 7.95%and 12.20%,acetic acid concentration increased by 5.11%and 10.38%,propionic acid concentration increased by 16.50%and 21.53%,butyric acid concentration increased by 15.50%and 2.29%,respectively,but there was no significant difference among all groups(P>0.05).These results indicated that the rumen degradation characteristics of oat hay from Gansu and Ningxia were similar,and the difference between them and the oat hay from Australia was great.