复合植物精油对肉鸡生长性能、免疫功能及抗氧化能力的影响

试验旨在研究肉鸡日粮中添加复合植物精油(牛至精油、肉桂醛、桉叶油)对肉鸡生长性能、免疫功能和抗氧化能力的影响。试验选择120只1日龄的体重接近、健康的肉仔鸡,随机分为4组,每组3个重复,每个重复10只鸡。对照组肉鸡饲喂基础日粮,低、中、高剂量组分别在日粮中添加100、200、300 mg/kg复合植物精油。肉鸡分1~21、22~42、43~60 d 3个阶段饲养,试验期60 d。结果显示,中、高剂量组肉鸡在1~21、22~42、1~42 d平均日增重(ADG)显著高于对照组和低剂量组(P<0.05),料重比(F/G)显著低于其他2组(P<0.05)。低、中、高剂量组肉鸡43~60 d平均日采食量(ADFI)显著高于对照组(P<0.05)。中、高剂量组肉鸡血清中新城疫抗体效价、血清免疫球蛋白(IgG、IgA、lgM)含量均显著高于对照组和低剂量组(P<0.05)。低、中、高剂量组肉鸡血清中总抗氧化能力(T-AOC)、总超氧化物歧化酶(T-SOD)活性显著高于对照组(P<0.05),丙二醛(MDA)含量显著低于对照组(P<0.05)。研究表明,饲粮中添加复合植物精油能够改善肉鸡生长性能,增强机体免疫功能及抗氧化能力,添加量为200 mg/kg较为适宜。

Dietary aflatoxin B1 induces abnormal deposition of melanin in the corium layer of the chicken shank possibly via promoting the expression of melanin synthesis-related genes

San-Huang chicken is a high-quality breed in China with yellow feather, claw and break. However, the abnormal phenomenon of the yellow shank turning into green shank of San-Huang chicken has been a concern, as it seriously reduces the carcass quality and economic benefit of yellow-feathered broilers. In this study, the cause of this abnormal green skin in shank was systematically investigated. Physiological anatomy revealed that the abnormal skin in shank was primarily due to the deposition of melanin under the dermis. After analyzing multiple potential causes such as heredity(pedigree and genetic markers), environment(water quality monitoring) and feed composition(mycotoxin detection), excessive aflatoxin B1(AFB1) in feed was screened, accompanied with a higher L-dihydroxy-phenylalanine(L-DOPA)(P<0.05) and melanin content(P<0.01). So it was speculated that excessive AFB1 might be the main cause of abnormal green skin in shank. Subsequently, the further results showed that a high concentration of AFB1(>170 μg kg–1)indeed induced the abnormal green skin in shank compared to the normal AFB1 content(<10 μg kg–1), and the mRNA levels of TYR, TYRP1, MITE, MC1R and EDN3 genes related to melanin deposition would significantly up-regulate(P<0.01) and the content and activity of tyrosinase(TyR) significantly increased(P<0.05). At the same time, the content of L-DOPA and melanin deposition also increased significantly(P<0.01), which also confirmed the effect of excessive AFB1 on melanin deposition in skin of shank. Results of additional experiments revealed that the AFB1's negative effect on melanin deposition in skin of shank could last for a longer time. Taken together, the results of this study explained the occurrence and possible mechanisms of the abnormal AFB1-related green skin in shank of chickens. Excessive AFB1 in diets increased the L-DOPA content and melanin abnormal deposition in the chicken shank possibly via promoting TyR content and activity, and the expression of melanin synthesis-related genes. Furthermore, our findings once again raised the alarm of the danger of AFB1 in the broiler production.

基于灵敏度修正的含风电场电力系统可用输电能力计算

为了在线评估风电场功率波动对可用输电能力(ATC)的影响,本文提出了基于灵敏度修正的含风电场电力系统ATC计算方法。基于风电场输出功率波动性的特点,在风电机组功率波动引起其他发电机有功出力方式发生变化情况下,利用灵敏度修正支路有功功率,校正支路有功对控制参数的灵敏度,通过考虑支路热稳定约束,建立ATC与系统发电机有功功率变化参数的映射关系,并根据电力系统当前运行点的特性确定了灵敏度应用的有效区间,快速计算由于风电机组功率变化导致常规发电机不同出力方式下的ATC。对含风电场的IEEE-30节点系统仿真结果表明,本文所提方法能够准确计算由于风电波动导致常规机组运行方式变化情况下的ATC,且计算时间满足在线计算要求。

同时检测H5和N8亚型AIV双重纳米PCR方法的建立和应用

建立了一种同时检测H5亚型和N8亚型禽流感病毒(AIV)的双重纳米PCR(nano-dPCR)方法,运用该方法可以同时检测出H5亚型和N8亚型AIV。登录GenBank下载H5亚型AIV HA和N8亚型AIV NA基因的序列进行比对分析,依据分析结果进行特异性引物的设计。经过多次验证实验,筛选出最佳的两对引物组合进行nano-dPCR反应体系的建立并优化反应条件,同时进行特异性实验、敏感性实验和临床样品检测验证。实验结果表明:该方法特异性良好,其他不同禽流感亚型及禽病病原体均未扩增出任何特异性条带,H5亚型AIV和N8亚型AIV的最低核酸检测量均达到了5×102拷贝/μL,其敏感性是普通PCR检测方法的100倍,可以用于临床样品检测。所建立的nano-dPCR检测方法可以同时对H5亚型和N8亚型AIV进行检测,具有很好的特异性和敏感性,为H5亚型和N8亚型AIV防控提供了新的技术支撑。