【摘要】 150只一日龄罗曼混合肉雏被随机分为四组,分别饲喂含维生素A为0、750、3000和6000IU的日粮。在20、30和45日龄时,每组剖检5只鸡,分离并称重免疫器官后,取材,石蜡包埋,切片,镜检。结果表明:维生素A缺乏和不足使免疫器官组织萎缩,间质结缔组织增生,上皮角化,腔上囊和胸腺的相对重量明显减少(P<0.01)。对免疫器官的损害程度是腔上囊>胸腺>脾脏>盲肠扁桃体。提高日粮中维生素A含量有提高肉雏增重、饲料报酬和免疫器官相对重量之趋势。更多还原

【Abstract】 One hundred and fifty day-old Lohman broilers were randomly divided into 4 groups. They were fed a diet supplemented with retinol acetate at a dose of 0 , 750, 3000 and 6000 IU per kg respectively. At the 20th, 30th and 45th day of age, five chicks of each group were killed respectively; the spleen, bursa of Fabricius and thymus were removed , weighed , embeded and sectioned routinely for histological study. The results showed that vitamin A-free or/and vitamin A deficiency caused atrophy of the immune organ, hyperplasia of the connective tissue in the interstitium,epithelium keratinization. The relative weights of the bursa of Fabricius and thymus decreased significantly. The severity of damage was in the following sequence: bursa of Fabr-icius>thymus>spleen>the tonsil of the caeca. Raising vitamin A level in the diet ( 6000 IU per kg ), there was a trend of increasing in growth rate, food conversion rate and the relative weight of the spleen, thymus and bursa of Fabricius.更多还原