Scrub-itch mite infestation in the endangered bridled nailtail wallaby

Skin lesions on the ears and inguinal and axillary regions of a number of adult animals within a captive population of the endangered bridled nailtail wallaby ( Onychogalea fraenata ) were associated with the trombiculid mite, Eutrombicula hirsti . The local inflammatory response of these Australian marsupials is described.     

模拟林(竹)-草种植模式遮荫对扁穗牛鞭草的光合速率、生长的影响及其经济效益分析

在模拟遮荫条件下对扁穗牛鞭草的净光合速率、生长指标和经济效益进行了分析。结果表明,扁穗牛鞭草在自然光强1 200μmol/(m2.s)左右时达到饱和点,遮荫48%~79%的光强下很难达到光饱和状态;在中、低光强辐射时,遮荫16%~79%的净光合速率仅为全光下的33.8%~86.4%,高光强辐射下,不同遮荫度下的净光合速率为其全光照的35.0%~94.7%;不同光照强度或者同一光照强度的不同遮荫梯度下,扁穗牛鞭草净光合速率都表现出显著差异[F遮荫=44.09>F0.05(3.84),Pv<0.05;F光照=11.72>F0.05(4.46),Pv<0.05];遮荫改变了光照条件,影响光合产物的合成,进而抑制了扁穗牛鞭草的茎粗生长、植株萌发以及生物量的积累,对株高生长则表现为抑制和促进2个方面;不同遮荫梯度下扁穗牛鞭草产值下降幅度为35.0%~83.1%,年产出0.512 3万元/hm2为扁穗牛鞭草种植的临界值,林(竹)-扁穗牛鞭草模式的冠层遮荫度需等于或小于43%,才能有一定的经济效益。     

棉隆熏蒸加短期轮作葱对平邑甜茶幼苗生长及其生理的影响

以盆栽平邑甜茶幼苗为试材,连续2年研究了老龄苹果园土壤经棉隆熏蒸后轮作一茬葱对再植平邑甜茶植株生理特征的影响,为其减轻苹果连作障碍提供理论依据。结果表明：老龄苹果园土壤轮作葱、棉隆熏蒸、棉隆熏蒸后短期轮作葱均能显著促进连作土壤再植平邑甜茶幼苗的生长,其中以棉隆熏蒸后短期轮作葱处理效果最佳。与棉隆熏蒸相比,棉隆熏蒸加短期轮作葱处理的平邑甜茶株高、地径、鲜质量、干质量、根系呼吸速率在2016年7月分别提高了34.5%、19.5%、30.0%、22.6%、21.3%,2017年7月,上述指标分别提高了29.9%、28.4%、35.0%、34.4%、26.5%;棉隆熏蒸后短期轮作葱还显著降低了根系及叶片中MDA含量,提高了根系抗氧化酶（SOD、POD、CAT）活性,两者联用处理的平邑甜茶幼苗净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、胞间CO2浓度（Gi）等较棉隆熏蒸也有显著提高。因此,棉隆熏蒸后短期轮作葱能有效防控苹果连作障碍。     

好氧反硝化细菌的筛选

采集江安河及府河淤泥样本,采用BTB培养基与N-(1-萘基)-乙二胺光度法筛选出20株具有反硝化能力的好氧菌株.选取其中5株反硝化能力较强的DM1、DM2、DM3、DM4和DM5菌株,进行NO3--N去除率测定,其48 h NO3--N去除率均达到了30％以上.其中DM1、DM2、DM3和DM5菌株氮去除率依次为43.9％、47.6％、47.9％和51.3％.对DM5菌株进行生长曲线测定,进行pH值和温度对反硝化速率影响测定,试验结果表明在pH 7.0～7.4,温度20～30℃时,DM5菌株反硝化效果较好.     

冬季羔羊舍饲育肥中应用膨润土的试验研究

在玉米秸为主的日粮中每头添加膨润土１６ｇ／ｄ和羟甲基尿素２０ｇ／ｄ进行羔羊快速育肥试验。结果表明,羔羊日增重由对照组的６５．００ｇ提高到试验组的１２０．６３ｇ,二者差异显著（Ｐ＜０．０５）。饲料转化效率提高４６．０１％。４０ｄ后羔羊瘤胃液ｐＨ值明显降低。膨润土能改善羔羊瘤胃消化代谢并促进羔羊生长。     

Effect of Estradiol-17β on protein synthesis and degradation rates in fused bovine satellite cell cultures

Although androgenic and estrogenic steroids are widely used to enhance muscle growth and increase feed efficiency in feedlot cattle, their mechanism of action is not well understood. Further, in vivo studies indicate that estradiol (E2) affects muscle protein synthesis and/or degradation, but in vitro results are inconsistent. We have examined the effects of E2 treatment on protein synthesis and degradation rates in fused bovine satellite cell (BSC) cultures. Additionally, to learn more about the mechanisms involved in E2-enhanced muscle growth, we have examined the effects of compounds that interfere with binding of E2 or insulin-like growth factor (IGF)-1 to their respective receptors on E2-induced alterations in protein synthesis and degradation rates in BSC cultures. Treatment of fused BSC cultures with E2 results in a concentration-dependent increase (P < 0.05) in protein synthesis rate and a decrease (P < 0.05) in protein degradation rate. The pure estrogen antagonist ICI 182 780 suppresses (P < 0.05) E2-induced alterations in protein synthesis and degradation in fused BSC cultures. The G-protein coupled receptor (GPR)-30 agonist G1 does not affect either synthesis or degradation rate, which establishes that GPR30 does not play a role in E2-induced alterations in protein synthesis or degradation. JB1, a competitive inhibitor of IGF-1 binding to the Type 1 insulin-like growth factor receptor (IGFR-1), suppresses (P < 0.05) E2-induced alterations in protein synthesis and degradation. In summary, our data show that E2 treatment directly alters both protein synthesis and degradation rates in fused BSC cultures via mechanisms involving both the classical estrogen receptor (ER) and IGFR-1.     

放牧季节及放牧强度对高寒草地植物多样性的影响

在海北高寒草地进行了7年轻度放牧、中度放牧和重度放牧试验,并用围栏控制放牧进行对照.试验显示,物种丰富度和均匀度在夏季牧场和冬季牧场出现不同的变化.在夏季牧场,物种丰富度随着放牧强度的增强而增强,而均匀度则随着放牧强度的增强而下降;在冬季牧场,物种丰富度和放牧之间呈现驼峰反应模式,说明植物的丰富度在中度放牧强度时达到最大.不同牧场生物多样性变化的模式说明夏季牧场放牧强度不足.     

品种及初生重对仔猪死亡率和21日龄个体重的影响

试验对2 319头仔猪的初生重与21日龄个体重和死亡率进行分析。结果表明:大约克仔猪哺乳期死亡率最低,21日龄体重最高;随着初生重的增加,仔猪死亡率降低,21日龄个体重增加。     

Pregnancy Rate in Zebu Cows with Two Different Postpartum Intervals Exposed to a Two-Bull Rotational System

In order to evaluate the reproductive effect of a rotational breeding system, the pregnancy rate of 69 Zebu cows was assessed, 32 late postpartum (211±93 days postpartum, LP) and 37 early postpartum (averaging 63±8 days after calving, EP). In the LP group, 60% (19/32) were cycling before exposure to the bulls but only 38% (14/37) in the EP group. The two groups were dissimilar from the start (p<0.05). The cows were exposed in a rotational breeding system, with six Brahman bulls with previous sexual experience paired off in three groups (A–B, C–D and E–F). The cows were exposed to each pair of bulls for a period of 3 weeks, with one week in between each period, when the females were without the presence of a male. In the LP group, the pair of bulls A–B obtained a pregnancy rate of 72% (23/32), whereas for bulls C–D the pregnancy rate was 33% (3/9) and for bulls E–F the pregnancy rate was 67% (4/6). In contrast, for the EP cows, bulls A–B obtained a pregnancy rate of 32% (12/37), bulls C–D a pregnancy rate of 67% (12/18) and for bulls E–F a pregnancy rate of 55% (6/11). The percentage pregnancy obtained using the pair of bulls A–B differed (p<0.05) between LP and EP, whereas for bulls C–D and E–F it was similar. The pregnancy rate was different (p<0.05) in the first 3 weeks of mating for the LP group, the highest number of cows becoming pregnant during the first 3 weeks of the study. In contrast, the highest number of pregnancies in EP occurred evenly during the last 6 weeks. This study suggests that the reproductive performance of pairs of bulls in a 9-week rotational programme with the overall pregnancy rate is similar (94% in the LP and 81% in the EP). However, the time taken for the females to become pregnant, and hence the performance of the bulls, is related to the average number of days postpartum for the cows.