加拿大奶牛业考察见闻

笔者于2002年6月28日至9月12日赴加拿大挑选优秀高产奶牛 ,在此期间 ,对加拿大奶业的组织结构、高产优质的牛群种质、丰富的饲料饲草资源、完善的社会服务体系、科学规范的奶牛场管理、高效率的机械化程度进行考察了解 ,学习和了解了加拿大奶业生产的先进经验 ,现做一小结 ,供大家参考。1加拿大奶牛业概况加拿大绝大部分地区自然条件和饲料资源丰富 ,都适宜饲养奶牛 ,魁北克省和安大略省饲养奶牛头数最多 ,占全国饲养量的75%。加拿大的奶业是以170万头泌乳奶牛和青年奶牛 (2岁以上 )为基础的 ,其中90.1 %的奶牛品种为荷斯坦牛 ,4.4 %为爱尔…     

云南冷凉山区退耕还草混播组合筛选研究

为了配合云南省退耕还草工作的全面实施,2002-2003年在滇西北冷凉山区退耕地带进行了牧草混播组合的筛选试验。根据各混播组合的草层高度、豆草率、叶比重和干草产量等经济指标,筛选出适合云南冷凉山区退耕还草的最佳混播组合是:多年生黑麦草+白三叶。该组合在生长的第2年至少可刈割2次,干草产量达到7688.68kg/hm2,成年植株草高为62.3cm;群落中豆科牧草的比重可达44.5%,叶所占的比例达到55.6%;而且地表始终覆盖良好。其次可选用多年生黑麦草+紫花苜蓿混播组合,其综合经济性状略低于前一组合。     

结核杆菌特异性诊断抗原的研究

在人类及动物疾病中 ,传染病是引起死亡率最高的疾病。其中结核病是人畜健康的主要威胁。据统计 ,目前全球人群中结核杆菌感染者约17～20亿 ,结核病人约2000万 ,每年至少3000万人感染结核 ,约800万新结核病患者 ,200余万人死于本病 [1]。随着爱滋病感染人数的剧增 ,结核与爱滋病的混合感染日趋严重 ,每年约有15 %的爱滋病感染者死于结核。结核病的免疫和治疗仍是医学界的一大难题 ,唯一的疫苗—BCG免疫效果不稳定 ,药物治疗亦被耐药性问题所困扰。因此在结核病感染的早期建立快速的诊断方法对于本病的控制无疑具有举足轻重的作用。结核病…     

代谢激素及营养对牛卵泡发育的影响

营养与牛繁殖的关系十分复杂，它影响到繁殖过程的诸多方面。该文仅局限于讨论其对卵泡发育的影响，即代谢激素(GH，IGF—1，INS)及短期增加日粮摄入对青年母牛卵泡发育的影响。并讨论营养与代谢激素，卵泡发育的相互关系及生产中的一些实际问题，如高产奶牛繁殖率下降，超排反应不稳定等问题。     

甘蓝型油菜（B.napusL.）细胞核雄性不育系杂种“中杂3号”的选育和遗传分析

以70-506花叶自交系中的天然雄性不育株为母本,先后同齐菲和加油3号杂交以改良综合经济性状。再连续用兄妹交保持和选择,育成1081AB雄性核不育“两用系”。通过不同品种测交和选育,育成恢复系1081C。在组合鉴定试验中,F1杂种比CK(甘油5号)增产30％;在湖北省油菜区试中比“中油821”增产11.45％,含油量高3.92％,成熟早3.8天。并对1081AB不育系的遗传组成作了初步分析。     

黄瓜新品种“绿优一号”的选育

"绿优一号"是山东省华盛农业股份有限公司以HS267014为母本,HS6201为父本选育的适应性广、高产、商品性佳的一代杂交黄瓜新品种。该品种早熟,长势强,高抗白粉霜霉病。第一雌花坐果节位为第4~5节,结成率为60%~80%,连续带瓜力强。商品瓜深绿有光泽,瓜长30~35cm,直径3.2~3.5cm。品种适应性强,早春、秋延迟及春秋露地均易栽种。     

EDACO,a derivative of myricetin,inhibits the differentiation of Gaoyou duck embryonic osteoclasts in vitro

1. This study determined the effects of (E)-3-(2-(4-(3-(2,4-dimethoxyphenyl)acryloyl)phenoxy)ethoxy)-5,7-dimethoxy-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one (EDACO) on the differentiation of Gaoyou duck embryonic osteoclasts cultured in vitro.

2. Bone marrow mononuclear cells (BM-MNC) were collected from 23-d-old Gaoyou duck embryos and induced by macrophage colony-stimulating factor and receptor activator of nuclear factor κB ligand in the presence of EDACO at different concentrations (i.e. 10, 20, 40, 80 and 160 µM). Tartrate-resistant acid phosphatase (TRAP) staining and resorption ability determination were conducted.

3. Results suggested that EDACO suppressed the shaping of positive multinucleated cells and the number of TRAP-positive cells in the 20, 40, 80 and 160 μM EDACO groups was significantly decreased (P < 0.05 or P < 0.01). Besides, the absorption activity of differentiated duck embryonic osteoclasts was significantly inhibited (P < 0.05) in both 80 and 160 μM EDACO groups.

4. Overall, EDACO can inhibit the differentiation of BM-MNC into mature osteoclasts in duck embryos.1     

Interactions between commensal bacteria and the gut-associated immune system of the chicken

The chicken gut-associated lymphoid tissue is made up of a number of tissues and cells that are responsible for generating mucosal immune responses and maintaining intestinal homeostasis. The normal chicken microbiota also contributes to this via the ability to activate both innate defense mechanisms and adaptive immune responses. If left uncontrolled, immune activation in response to the normal microbiota would pose a risk of excessive inflammation and intestinal damage. Therefore, it is important that immune responses to the normal microbiota be under strict regulatory control. Through studies of mammals, it has been established that the mucosal immune system has specialized regulatory and anti-inflammatory mechanisms for eliminating or tolerating the normal microbiota. The mechanisms that exist in the chicken to control host responses to the normal microbiota, although assumed to be similar to that of mammals, have not yet been fully described. This review summarizes what is currently known about the host response to the intestinal microbiota, particularly in the chicken.     

牛种布鲁氏菌clpP基因缺失株的毒力和免疫保护力评价

为研究布鲁氏菌clpP基因与细菌毒力的关系,采用同源重组的方法,构建牛种布鲁氏菌clpP基因缺失株,用巨噬细胞RAW264.7感染模型和小鼠感染模型评价clpP基因缺失株的毒力,同时测定该缺失株免疫小鼠后产生的免疫保护力。研究发现:牛种布鲁氏菌clpP基因缺失后,在细胞感染模型和小鼠感染模型中的毒力显著降低;clpP基因缺失株感染小鼠后,不引起脾脏肿胀,并且在脾脏内的持续期短于A19疫苗株,说明该基因缺失株具有更高的安全性;使用clpP基因缺失株免疫小鼠后,该基因缺失株无法抵御牛种布鲁氏菌2308株和羊种布鲁氏菌M28株的感染。本研究为揭示布鲁氏菌致病机制和新型布病疫苗研发提供了参考。