Ascorbic acid ameliorates dysregulated folliculogenesis induced by mono-(2-ethylhexyl)phthalate in neonatal mouse ovaries via reducing ovarian oxidative stress

Phthalates, including di-(2-ethylhexyl)phthalate (DEHP), are common industrial chemicals in the environment. Recent evidence indicates that DEHP and its active metabolite mono-(2-ethylhexyl)phthalate (MEHP) negatively modulate reproductive functions and induce reactive oxygen species. Ascorbic acid (AA) is a dietary requirement for primates, and it acts as a potent free radical scavenger to protect tissues against oxidative stress. In this study, to investigate the toxic effects of MEHP on the follicle development and the beneficial role of AA, neonatal mouse ovaries were treated with different concentrations of MEHP with or without AA for 6 days. Then, the follicle constitution and oxidative status were compared in different groups. Results showed MEHP accelerated primordial follicle recruitment by increasing the percentage of primary and secondary follicles and decreasing the percentage of primordial follicles in the ovaries. Moreover, MEHP-induced ovarian oxidative stress by significantly increasing malondialdehyde (MDA) concentration and the expression of GSS and SOD1. When ovaries were co-administrated with MEHP and AA, follicle constitution was normalized, and the oxidative status was significantly decreased. These results suggested that AA ameliorated MEHP-induced ovarian oxidative stress and follicular dysregulation, which attested the clinical significance of AA for ovary protection in the case of MEHP exposure.     

Dietary supplementation with sodium bicarbonate improves calcium absorption and eggshell quality of laying hens during peak production

1. The advantage of supplemental sodium bicarbonate (NaHCO₃) on eggshell quality in laying hens changes with age. Besides increasing calcium (Ca) secretion in the eggshell gland, it may improve Ca absorption in the intestine or kidney.

2. Hy-Line Brown layers (n = 384), 25 weeks of age, were allocated to two treatment groups in two experiments, each of which included 4 replicates of 24 hens. Hens were fed a basal diet (control) or the basal diet containing 3 g NaHCO₃ g/kg for 50 or 20 weeks in Experiment 1 or 2, respectively. A 24-h continuous lighting regimen was used to allow hens to consume the dietary supplements during the period of active eggshell formation.

3. In Experiment 1, particularly from 25 to 50 weeks of age, and in Experiment 2, NaHCO₃ supplementation favoured hen-d egg production at the expense of lower egg weight. The increased eggshell thickness should have nothing to do with the additional eggshell formation, because of the unchanged egg mass and daily eggshell calcification.

4. At 35 weeks of age in both experiments, NaHCO₃ supplementation increased duodenal expression of calbindin-d28k (CaBP-D28k) protein, contributing to higher Ca retention and balance.

5. From 50 to 75 weeks of age in Experiment 1, the hens had little response to NaHCO₃ supplementation and showed a negative trend on eggshell thickness and strength.

6. It is concluded that dietary supplementation with 3 g NaHCO₃ g/kg improves Ca absorption and eggshell quality of laying hens during the peak but not late production period, with the introduction of continuous lighting.

     

当前畜产品质量安全问题与对策刍议

放心肉、放心奶、放心蛋真能让人放心么?近年来,国际上先后发生牲畜口蹄疫、疯牛病、二口恶英、禽流感事件,我国也相继发生"瘦肉精"、"苏丹红"事件及亚洲I型口蹄疫、禽流感、人感染猪链球菌病、高致病性猪蓝耳病、兽药残留等问题。2008年9月石家庄三鹿奶粉事     

中能中蛋白水平下维生素A、D3对0～6周龄肉仔鸡生产性能的影响

采用3×3随机交叉试验设计,研究中能中蛋白水平下日粮VA、VD3对肉仔鸡生产性能的影响。1日龄AA肉仔鸡540只随机分为9组,每组3个重复,每重复20只鸡。3个VA添加水平为3000、6000、12000IU/kg;3个VD3添加水平为200、400、800IU/kg;0～3和4～6周龄基础日粮代谢能、粗蛋白水平分别为12.34MJ/kg,21%;12.76MJ/kg,19%。结果表明:①日粮VA水平对体增重、耗料量、料重比、存活率均无显著影响(P>0.05);②随VD3添加水平的增加,体增重、耗料量、存活率显著增加(P<0.05);③综合考虑生产性能和经济效益,认为0～3和4～6周龄肉仔鸡日粮VA添加量均以3000IU/kg较为适宜,VD3添加量均以800IU/kg较为适宜。     

中草药、益生素和抗生素对猪生长性能和免疫功能的影响比较试验

本试验旨在比较中草药、益生素和抗生素对生长猪生产性能和免疫功能的影响。试验选取15kg左右的杜×长×大三元杂交猪90头,随机分为抗生素组、0.2%益生素组和0.2%中草药组,每组3个重复,每个重复10头猪,试验时间28d。结果表明:(1)与抗生素组相比,益生素及中草药组的日增重提高、料重比降低(P>0.05);(2)中草药组的IgG、IgM、IgA、C3、C4含量和益生素组的IgG含量均显著提高(P<0.05)。结论:在生长猪日粮中添加0.2%益生素或中草药能够促进动物生长,提高免疫功能,效果优于抗生素。     

活禽交易对十堰市公共卫生安全的影响及对策

本文针对十堰市活禽养殖和交易的现状,结合工作实际,分析了活禽交易方式对公共卫生安全、禽流感防控、环境污染等方面的影响,以及活禽交易存在的问题及产生的原因,从政策建议、防疫条件、检疫监管、疫情监测预警、市场准入、可追溯体系建设、动物经纪人管理等方面提出了措施和建议,为进一步加强禽流感防控工作和动物产品质量安全管理提出了有益的探讨。     

白腐菌及黑曲霉对玉米秸秆生物降解的研究

利用白腐菌5.776和黑曲霉3.3148对玉米秸秆木质纤维素进行降解,以提高反刍动物对玉米秸秆的消化利用。先对白腐菌和黑曲霉降解玉米秸秆木质纤维素的能力进行了研究,在此基础上,采用正交试验,探索白腐菌和黑曲霉混合后对玉米秸秆的降解效果。结果表明,接种比例、黑曲霉接入时间,接种比例与黑曲霉接入时间的交互作用以及发酵时间对混菌发酵降解玉米秸秆都有显著影响(P<0.05)。最佳方案为:白腐菌液体菌种和黑曲霉孢子悬浮液的接种比例为5:1,白腐菌接种2 d后再接入黑曲霉孢子悬浮液,发酵10 d,所得产物中性洗涤纤维的含量为52.07%,真蛋白为7.89%,干物质损失率为18.75%。     

奶牛环形泰勒焦虫病诊治报告

２０００年６月上旬至７月下旬，我县营子、七贤等乡镇发生一种呈地方性流行或散发的急性奶牛疾病，以高热稽留、体表淋巴结肿大、贫血为主要特征。根据流行病学、临床症状、剖检变化、实验室诊断，确诊为奶牛环形泰勒焦虫（Ｔ．ａｎｎｕｌａｔａ）病，现报告如下：１流行病学从６月上旬开始陆续发病，发病率达２５％，其中死亡２头。该病以一胎母牛多发。经调查，多为带犊由外地购进，本地饲喂时间不足一年。检查牛体，能发现吸饱血或未吸饱血的豆粒大或米粒大牛蜱。２临床症状病牛初期体温上升高达４１℃，稽留热。肩前和鼠蹊淋巴结肿大，…     

肝片形吸虫雷蚴与尾蚴的扫描电镜观察

肝片形吸虫的母雷蚴、早期子雷蚴、成熟子雷蚴及尾蚴表被结构经扫描电镜观察：在母雷蚴及早期子雷蚴的口孔周围有乳突分布；雷蚴的围领呈领圈样环绕，围领基部的一侧有一个产孔，产孔的开口处呈唇样的构造，从母雷蚴、早期子雷蚴至成熟子雷蚴的发育，其体表绒毛样构造日趋发达。尾蚴背部密布尖刀形棘，腹部具有许多不规则的突起，其间分布有许多微孔；口吸盘及周围无乳突分布，但在腹吸盘周围分布有排列整齐的指状突起。尾蚴体部与尾部相连处有一环形颈状结构，尾蚴尾干背面为一槽状的皱襞。     

ELISA对动物舍气载魏氏梭菌型别的研究

采用ELISA方法对从一个犊牛舍空气中分离到的魏氏梭菌进行型别的鉴定。结果显示：88％的菌种属于A型，3.4％为C型，8.6％是D型，B型未能确认。