The effects of chronic intermittent noise exposure on broiler chicken performance

Effects of different noise levels (70 or 80 dB) that broilers were exposed to during the entire fattening period and also the effect of the timing of the first exposure to intermittent noise in the course of fattening (day 1 vs. day 7) were monitored. After 7 days of exposure to intermittent noise, experimental chickens already showed a significant decrease in live body weight in comparison with the control group. The difference between the group exposed to intermittent noise at 70 dB and the group exposed to 80 dB levels was not statistically significant, although the mean live body weight of broilers in the latter was lower during the entire fattening period. The chickens exposed to intermittent noise from day 1 of age showed lower mean live weight throughout the fattening period compared to chickens exposed to the same level of intermittent noise only from day 7 of age, although at the end of fattening the difference was statistically significant only in chickens exposed to the higher level of intermittent noise (80 dB).     

甘草查尔酮A对副猪嗜血杆菌的体内外抑制作用

探讨甘草查尔酮A对副猪嗜血杆菌体内外生长的影响。将副猪嗜血杆菌于分别含10、20、50、100、200μg/mL甘草查尔酮A的TSA液体培养基中培养,采用分光光度法分析副猪嗜血杆菌生长和生物被膜形成的变化;以1、10、100mg/kg甘草查尔酮A经口灌胃小鼠,分别在3d、5d和7d称重,并计算脏器指数,Hiseq高通量测序技术分析肠道菌群等生长性能,Bliss法测定副猪嗜血杆菌对小鼠半数致死量(LD50);检测甘草查尔酮A对小鼠清除0.01×LD50副猪嗜血杆菌感染和抵抗100×LD50副猪嗜血杆菌感染的影响。结果表明,各浓度甘草查尔酮A对副猪嗜血杆菌的生长速率和生物被膜形成的影响差异均无显著差异。所有剂量组小鼠给予甘草查尔酮A处理后,一般临床症状、体重和脏器指数无统计学意义。灌喂甘草查尔酮A有增加小鼠肠道菌群丰富度的趋势,但降低拟杆菌门丰度而增加厚壁菌门丰度。小鼠清除0.01×LD50副猪嗜血杆菌感染的能力呈剂量依赖性,而100×LD50的副猪嗜血杆菌感染小鼠后随着甘草查尔酮A浓度增加可呈剂量依赖延迟小鼠死亡时间。表明甘草查尔酮A对副猪嗜血杆菌体外生长无显著的抑制作用,同时对小鼠生长性能亦无明显影响,但可增加肠道菌群丰富度而提高小鼠抵抗副猪嗜血杆菌感染的能力。     

Efficacy of Sarafloxacin in Broilers after Experimental Infection with Escherichia coli

Infections of chickens with Escherichia coli serotypeO78 can be treated with the antibiotic sarafloxacin. Three experiments were conducted on the administration of this drug to chickens that had been experimentally infected with E. coli. The birds were monitored for 10 days after infection for their average daily gain (ADG) and feed conversion ratio (FCR), and the post-mortem pathology was assessed. In the first experiment, sarafloxacin (20 mg/L, equivalent to 5 mg/kg live weight per day), given in the drinking water for 3 days after infection, led to a reduction in the mortality from 75% to 27%, but the ADG of the treated birds was still less than that of the uninfected controls. In the second experiment, when the sarafloxacin was administered at the same dose in the water but over only 2 h, there was also a considerable reduction in mortality, and the ADG and the FCR also improved significantly. In the third experiment, the dose dependence of the drug was tested. The birds were given 5 and 10 mg/kg per day sarafloxacin in each group, starting within 2 h after infection. This rapid administration of the drug completely prevented mortality, while the ADG and FCR were similar to those of the uninfected controls.     

固定效应对槟榔江水牛体重影响的研究

[目的]槟榔江水牛为我国目前为止发现的唯一本土河流型水牛,具有产奶性能高、肉用性能好的特点,为了进一步阐明槟榔江水牛的生长发育规律,本文收集云南腾冲县巴福乐槟榔江水牛2004~2011年生长发育数据资料,研究性别、月份和年度等固定效应对体重的影响。[方法]应用SAS分析性别、月份、年度等非遗传因素对槟榔江水牛体重的影响,并且用MTDFREML软件分析了固定效应值。[结果]本研究结果表明,槟榔江水牛性别对初生重具有显著影响,公犊平均初生重(35.04kg)显著高于母犊(32.63kg);月份对母牛初生重没有显著影响,公牛的效应值比母牛的较大。[结论]月份对槟榔江水牛的体重有显著的影响,可能与饲料的季节性供给有关。     

河南大尾寒羊体重生长特性的研究

应用VonBertalanffy、Gompertz、logistic、幂函数非线性生长模型对河南大尾寒羊的生长进行了拟合,Gom-pertz和logistic方程能很好地反映河南大尾寒羊的生长特点。本品种具有较好的早熟性;粗放的饲养管理可导致羔羊断奶后体增重急剧减慢;利用回归方程计算的母羊适宜初配日龄为211￣240d。     

科尔沁草原主要草地植物传播生物学简析

本研究论述了科尔沁草原主要草地植物的传播生物学特性.在141种植物中,44种以种子作为传播体,97种以果实作为传播体;传播体重量< 0.1 mg的植物12种,重量0.1～0.999 9 mg的植物61种,重量1～9.999 9 mg的植物55种,重量10～99.999 9 mg的植物12种,重量100～999.999 9 mg的植物1种;具有典型聚合传播体的植物4种;具有典型多态传播体的植物1种;传播体具附属物的植物66种(占总数的46%),其中19种带冠毛,10种带绢毛或丝毛,15种带芒或刚毛,6种带翅,6种带钩或刺,10种带其他附属物(花柱、花萼、结块和喙等).在124种植物中,11种植物(7种蒿属植物、2种车前、百里香1种和野亚麻1种)种子具有粘液,其种子或果实的干重＜1 mg.已发现23种植物具有明显的植冠种子库(植冠种子库种子达到总结种量的5%).8种植物植冠种子库种子超过结种量的30%,7种植物达到结种量的20%～30%,8种植物少于结种量的20%.具有植冠种子库的植物以菊科(尤其蒿属)、禾本科和藜科植物为多.具有较强或相对较强沙生适应性的植物多数具有植冠种子库.探讨了传播体类型和重量、利于(或阻滞)传播的传播体特征、传播体多态性与传播适应的多面性、延缓传播与植冠种子库等方面的问题.     

Rotational and continuous grazing of sheep in the Inner Mongolian steppe of China

The aim of this study was to compare the effects of rotational and continuous grazing on herbage mass (HM), organic matter digestibility (dOM) and intake (OMI) and live weight gain (LWG) of sheep grazing on the inner Mongolian steppe, China at a stocking rate of 4.5 sheep/ha during the growing season. In the years 2005 and 2006, four 2-ha plots were used of which two were divided into four 0.5 ha paddocks each for rotational grazing, where sheep were moved each 10 days to the next paddock. The dOM was estimated from faecal crude protein concentration and OMI by oral administration of titanium dioxide. Herbage mass was similar in both grazing systems and dOM and OMI were higher (p < 0.05) at continuous grazing than at rotational grazing, but LWG did not differ probably because of extra energy expenditure for grazing and walking in a larger area. The dOM and OMI decreased (p < 0.05) with progress of the growing season and differed between years. Since precipitation during the growing season in both years was lower than the 30 years average which was probably the reason that positive effects of non-grazing periods on herbage regrowth and quality at rotational grazing could not occur, further studies are required in years with average precipitations before a final evaluation of these grazing systems can be made. Moreover, it seems necessary to quantify energy expenditure for physical activity of animals in grazing studies.     

The effect of selected microbial strains on internal milieu of broiler chickens after peroral administration

The aim of this work was to investigate the effect of probiotic preparation with multi-strains composition (Lactobacillus delbrueckii ssp. bulgaricus LAT 187, Lactobacillus acidophilus LAT 180, Lactobacillus helveticus LAT 179, Lactobacillus delbrueckii ssp. lactis LAT 182, Streptococcus thermophilus LAT 205 and Enterococcus faecium E 253) on internal milieu, antioxidant status and body weight of broiler chickens. Chickens were divided into three groups (C, control; E1 and E2, experimental groups). Experimental chickens received the probiotic preparation in drinking water. Probiotic preparation caused a significant increase of serum calcium and potassium content. In the group with higher dose of probiotic strains serum triglycerides level decreased. Total antioxidant status in groups with addition of probiotic strains showed higher values in comparison to control group. Serum albumin level was found to increase after consumption of probiotic preparation in group with higher dose of probiotic strains. Probiotic strains improved body weight in last observed weeks of feeding.     

生长牦牛血清钙和磷变化规律分析

利用原子吸收法和色谱法,对3组(G1:5～15月龄;G2:17～27月龄;G3:29～39月龄)生长牦牛血清中钙和磷浓度的变化规律进行了跟踪分析。结果表明:生长牦牛血清钙浓度为(10 235±0 809)mg/dL,与普通牛相当;但血清磷为(5 567±1 361)mg/dL,明显低于普通牛,导致血清钙与磷之比值较高,表明牦牛缺磷问题突出。各年龄段生长牦牛血清钙浓度顺序依次为G1相似文献   

安义瓦灰鸡早期生长规律研究

通过对不同羽速基因及不同性别安义瓦灰鸡的早期生长规律进行研究,结果表明:不同性别安义瓦灰鸡的早期生长规律有较大差异(P<0.01),不同羽速基因安义瓦灰鸡的早期生长规律差异不显著;安义瓦灰鸡的生长速度与出壳重无关,出壳重只影响其育雏期的体重;性别对体重的影响较晚,且公鸡大于母鸡。