本试验旨在研究不同起始pH对中药渣发酵特性的影响，评价中药渣饲料安全性以及其对肉羊育肥的效果。试验按照中药渣发酵起始pH设3个组：A1组（4.55）、A2（5.50）和A3组（6.90），每组均接种植物乳杆菌（Lactobacillus plantarum），接种量为0.5%，定时取样测定pH；发酵结束后分析中药渣中微生物蛋白和有机酸含量；采用高通量测序比较细菌多样性变化特征；测定发酵中药渣中重金属和真菌毒素含量，评价其安全性。选择30只当年出生、体重为（35.0±2.0）kg的湖羊公羊作为试验对象，随机分为对照组和试验组，每组15只，单栏喂养。对照组饲喂常规基础饲粮，试验组饲喂发酵中药渣（起始pH为6.90，发酵30 d）饲粮，饲喂70 d，研究发酵中药渣对肉羊育肥效果和抗氧化、免疫等指标的影响。结果表明：1）中药渣发酵到第6天时，所有组中药渣pH均下降到4.0以下，A3组微生物蛋白、乳酸和乙酸含量最高，比A1组分别提高14.72%、49.93%和22.77%（P<0.05），A2组介于两者之间。乳酸杆菌属（Lactobacillus）相对丰度随起始pH升高而提高，A2和A3组与A1组比较差异达到显著性（P<0.05），肠杆菌属（Enterobacter）、泛菌属（Pantoea）、苍白杆菌属（Ochrobactrum）、独岛氏菌属（Dokdonella）相对丰度与乳酸杆菌属变化趋势相反。发酵中药渣中重金属（铬、镉、铅和汞等）和黄曲霉毒素B₁含量符合国家饲料标准。2）发酵中药渣饲喂肉羊，与对照组相比，平均日增重提高6.4%（P>0.05），血清中生长激素含量显著高于对照组（P<0.05）；对血清中葡萄糖、胆固醇和总蛋白含量没有显著影响（P>0.05），对血清中睾酮、双氢睾酮、脱氢表雄酮和雄烯二酮含量也没有显著影响（P>0.05），但极显著提高了血清免疫球蛋白A、免疫球蛋白G和免疫球蛋白M含量（P<0.01）。综上所述，提高中药渣发酵起始pH发酵效果更好；发酵中药渣具有较高的营养价值和安全性；发酵中药渣饲喂肉羊具有促进机体生长和提高血清免疫球蛋白含量的作用。

This study was conducted to determine fermentation characteristics of Chinese herb residues (CHR) with different initial pH and its safety as feedstuff, and fattening effect of sheep. According to the initial pH value of CHR, this experiment were setup 3 groups: A1 group (4.55), A2 group (5.50) and A3 group (6.90), respectively. Lactobacillus plantarum was added to each group at an inoculation dosage of 0.5%. Samples were taken to determine pH; after fermentation, microbial protein and organic acid contents of CHR were determined; variation characteristics of bacterial diversity was determined by high throughput sequencing technique (Illumina Miseq); heavy metals and aflatoxin contents of CHR were evaluated for evaluating its safety. A total of 30 Hu sheep with a body weight of (35.0±2.0) kg were randomly divided into two groups: control group and test group with 15 sheep in each group, and fed separately. Control group was fed a basal diet, and test group was fed fermented CHR (initial pH was 6.90,and fermentation time was 30 d), and fed for 70 days. The effects of CHR on the fattening effect, antioxidant and immune indexes of sheep were studied. Results showed as follows: 1) pH of all groups decreased to below 4.0 at the 6th day of fermentation. The highest contents of microbial protein, lactic acid and acetic acid were found in A3 group, and they were 14.72%, 49.93% and 22.77% higher than those in A1 group (P<0.05), respectively. All data of A2 group were between A1 and A3. The relative abundance of Lactobacillus increased with the increase of initial pH, and there were significant difference in A2 and A3 groups compared with A1 (P<0.05). The relative abundance of Enterobacter, Pantoea, Ochrobactrum and Dokdonella decreased with the increase of initial pH. The highest relative abundance of Lactobacillus was found at the 3rd week of fermentation (P<0.05). The contents of heavy metals (chromium, cadmium, lead and mercury, etc.) and aflatoxin B₁ in CHR conformed to the national feedstuff standard. 2) The average daily gain of sheep fed fermented CHR increased by 6.4% compared with control group (P>0.05), and the content of growth hormone (GH) in serum was significantly higher than that in control group (P<0.05). There were no significant effect on glucose, cholesterol and total protein contents in serum (P>0.05), and were also no significant effect on testosterone, dihydrotestosterone, dehydroepiandrosterone and rostenedione contents in serum between two groups (P>0.05). The contents of immune globulin A, immune globulin G and immune globulin M in serum significantly increased (P<0.01). In conclusion, fermentation effects of CHR are better by increasing initial pH. Fermented CHR has higher nutrient value and safety, and not only promote sheep growth performance, but also increase immunoglobulin contents in serum.