中文摘要：

本试验旨在研究不同代乳条件下1~35日龄羔羊瘤胃及其微生物群落的发育。选取56只初生重（3 380±328）g的小尾寒羊公羊,从1日龄起分别饲喂牛奶粉代乳（milk powder substitute,MS,28只）或鱼粉代乳（fish meal substitute,FS,28只）,并在21日龄将饲喂2种代乳的羔羊各8只转喂开食料。在7、14、21、28和35日龄分别宰杀4只,进行瘤胃液细菌和原虫分类计数,测定瘤胃液真菌数量、挥发性脂肪酸和氨态氮（NH3-N）浓度,瘤网胃重量和结构形态指标。结果表明：1）饲喂MS羔羊瘤胃在7日龄即有细菌（85.47×109个/m L,97.4%为瘤胃球菌）和原虫（1.10×105个/m L）,且总数均随日龄增加而增加。7日龄羔羊瘤胃液真菌数量较少,直到35日龄时才较多。羔羊瘤胃在7日龄即有总挥发性脂肪酸（TVFA,乙酸为主）,但浓度在21日龄后才随日龄增加大幅上升。7日龄羔羊瘤胃液NH3-N浓度为33.2 mg/d L。饲喂MS的羔羊瘤网胃重量、瘤胃乳头长度和宽度随日龄增加而增加。2）与饲喂MS相比,饲喂FS的羔羊7日龄瘤胃液细菌和原虫总数分别减少30.8%（P〈0.01）和27.3%（P〉0.05）,瘤胃液TVFA和NH3-N浓度随日龄增加波动变化,35日龄瘤网胃重减少17.1%（P〉0.05）,瘤胃乳头长度和宽度分别减少16.0%（P〈0.05）和增加39.4%（P〉0.05）。3）21日龄给羔羊转喂开食料,原先饲喂MS羔羊28日龄瘤胃液细菌总数增加49.7%（P0.01）,原虫总数减少50.3%（P〈0.01）,TVFA浓度升高158.8%（P〈0.01）,瘤网胃重增加14.0%（P〉0.05）、瘤胃乳头长度变短43.3%（P〈0.01）,宽度增加61.8%（P〈0.01）;瘤胃液真菌数量在35日龄时显著增加。4）21日龄给羔羊转喂开食料,原先饲喂FS羔羊28日龄瘤胃液细菌总数增加21.1%（P〉0.05）,原虫总数减少60.4%（P〈0.01）,TVFA和NH3-N浓度各降低43.5%（P〉0.05）和49.1%（P〈0.05）,瘤胃乳头长度和宽度分别减少23.1%（P〈0.05）和11.2%（P〉0.05）;在35?

英文摘要：

This experiment was conducted to investigate the development of rumen and its microbiocoenosis of lambs at 1 to 35 days of age under different milk replacing conditions. Fifty six Small Tail Han lambs with the birth body weight of （3 380±328） g were selected and fed milk powder substitute （MS, 28 lambs） and fish meal substitute （FS, 28 lambs） since 1 day of age, respectively. At 21 days of age, eight lambs from each of the two milk substitute treatments were turned to feed a starter. At the age of 7, 14, 21, 28 and 35 days, four lambs were sacrificed, respectively, to determine the differential count of the bacteria and protozoa, the num- ber of fungus, the concentrations of volatile fatty acid （VFA） and ammonia nitrogen （ NHz-N） in rumen flu- id, and the weight and morphological structure indices of rumen-reticulum. The results showed as follows ： 1 ） there were protozoa （ 1.1×10^5 cells/mL） and bacteria （85.47×10^9 cells/mL, 97.4% Ruminococcus） in rumen fluid of lambs fed MS at the age of 7 days , and the total number increased with aging. There was a little of fungus in rumen fluid at 7 days of age, and the number became more until 35 days of age. Total VFA （ mainly as acetic acid） was already produced in rumen of lambs at the age of 7 days, and the concentration increased obviously after the age of 21 days. The NH3-N concentration in rumen fluid of lamb at 7 days of ages was 33.2 mg/dL. The weight of rumen-reficulum, and the height and width of rnmen papilla of lambs fed MS in- creased with aging. 2 ） Compared with MS, the total numbers of protozoa and bacteria in rnmen fluid of lambs fed FS were decreased by 30.8% （P〈0.01） and 27.3% （P〉0.05）, respectively, the total VFA and NHz-N concentrations in rumen fluid were changed dramatically with aging, the weight of rnmen-reficulum was de- creased by 17.1% at 35 days of age （P〉0.05）, the rumen papilla height was decreased by 16.0% （P〈0.05） , and the rumen papilla width was increased by 39.4% （P〉0