Evaluation of Associative Effect of Whole Corn Silage and Millet Straw by Gas Production Technique in vitro

This research adopted fermentation gas production method in vitro to evaluate the associative effect of whole corn silage (WCS) and millet straw (MS).The WCS was mixed with MS in the proportion of 100:0,80:20,60:40,50:50, 40:60,20:80 and 0:100 with 3 replicates per group.The gas production,pH,ammonia nitrogen (NH₃-N), volatile fatty acids (VFA), microbial crude protein (MCP) and dry matter loss (DML) for 24,48 and 72 h of varying forage combinations were analyzed.Single factor associative effects index (SFAEI) and multiply factors associative effects index (MFAEI) of different combinations were calculated. The results showed as follows:There were significant differences of gas production among different combinations (P<0.05),and the best combination was the WCS80 group. With creasing of the content of MS,DML decreased,but the DML of WCS80 and WCS100 were similar (P>0.05). The MCP concentration of WCS100 and WCS80 was extremely significantly or significantly higher than other groups (P<0.05;P<0.01). The VFA concentration showed significant differences among different combinations (P<0.05).Among the different combinations of WCS and MS,the MFAEI of WCS80 was the largest,and that were 0.5517,0.5094 and 0.9860 at 24,48 and 72 h,respectively. The best combination of WCS and MS was 80:20.     

Evaluation of Associative Effects of Alfalfa Meal and Ammoniated Corn Straw by Gas Production Technique in vitro

This experiment was conducted to determine the best roughage combination of alfalfa meal (AM) and ammoniated corn straw (ACS),so as to improve the efficiency of roughage utilization and reduce the cost of feeding. The AM was mixed with ACS in the proportion of 100:0,80:20,60:40,50:50,40:60,20:80 and 0:100 with 3 replicates per group. The accumulated gas production (GP) at fermentation for 3,6,12,24,48 h,and the changes of pH,dry matter disappearance rate (DMD),ammonia nitrogen (NH₃-N) concentration, microbial protein (MCP) and volatile fat acids (VFA) concentration,and their single factor associative effects index (SFAEI) and multiply factors associative effects index (MFAEI) were determined by gas production technique in vitro after fermentation for 48 h. The results showed as follows:The accumulated gas production of AM20:ACS80 group was higher than that of the other groups,and the DMD of AM0:ACS100 group was significantly lower than other groups (P<0.05).The NH₃-N concentration of AM20:ACS80 and AM0:ACS100 groups was significantly higher than the other groups (P<0.05).The MCP concentration was highest in AM20:ACS80 group,and the concentration of acetic acid and TVFA in AM20:ACS80 group was the highest (P<0.05),and the acetic acid/propionic acid ratio in all groups was more than 3,which indicating that it belonged to the acetic acid fermentation type.The pH during the fermentation ranged from 6.69 to 6.85.The results of MFAEI and SFAEI of each combination indicated that only the AM20:ACS80 group showed the positive associative effects. In conclusion,the 20:80 combination ratio for AM and ACS showed the best associative effects.     

蜂胶高生物活性黄酮组分的研究

本文探讨了蜂胶总黄酮中最具活性的黄酮类物质的提取分离、官能结构特征与功能关系、可能的功效,进而提出了如何看待蜂胶总黄酮含量高低的问题.     

大豆秸秆菌糠喂牛的效果研究

本试验用大豆秸秆菌糠替代50％,70％和100％粗饲料（干玉米秸）饲喂鲁西牛。结果表明,大豆秸秆菌糠替代粗饲料的比例以50％为宜,日增重比 对照组高131g,提高29．91％,差异极显著（P＜0．05）。     

Effects of Fire Exclusion on Previously Fire-Managed Semiarid Savanna Ecosystem

Long-term (> 100 yr) fire exclusion is associated with numerous ecological consequences in grasslands and savannas, including transitions into shrub- or tree-dominated systems. Several studies have reported differences in woody vegetation after multiple fires among burned and unburned rangelands, but none have reported the impacts of fire exclusion after a period of fire management. We evaluated effects of fire exclusion on herbaceous and woody canopy cover and herbaceous biomass in semiarid savanna of southwest Texas in pastures with known burn histories. Pastures were burned in summer and winter in 1994, 2000, and 2006, followed by 11 yr of fire exclusion. Between 2006 and 2017, woody subcanopy increased (5–21%) in all treatments while overstory canopy remained unchanged. Herbaceous cover decreased (5–18%) in all treatments but remained higher in burned treatments. From 2006 to 2017, herbaceous biomass declined in all treatments by > 650 kg·ha⁻¹ and was not statistically different among treatments. These trends support other research demonstrating the importance of historical mean fire return interval in maintaining grasslands and savannas.     

纳米微粒材料生物学活性研究进展

综述了纳米微粒的生物学效应及其免疫调节、抗菌、抗肿瘤等多种生物学活性.     

多拉菌素注射剂杀灭猪血虱试验

选购自然感染猪血虱的仔猪80头,根据猪血虱感染数量随机分为5组,分别肌肉注射多拉菌素400、300、200 μg/kg体重,皮下注射伊维菌素300 μg/kg体重,肌肉注射生理盐水0.5 mL/头.结果显示,各试验组药物对猪血虱都有明显的驱杀作用,其中多拉菌素高、中剂量组药物残效期达120 d以上.临床推荐剂量为300 μg/kg体重.     

芬苯哒唑控释丸对小尾寒羊线虫的临床驱虫效果

选取某羊场临床表现有线虫感染症状的病例,实验室检查证明为自然感染线虫的小尾寒羊20只,分为4组,依次用芬苯哒唑控释丸、0．2％伊维菌素、丙硫咪唑进行驱虫。分别于用药前及用药后第7天取粪便计数虫卵,并于用药后第2天起检查每天由粪便中驱出虫体数量,直至查不出为止。结果表明,芬苯哒唑对羊消化道线虫有更好的杀灭作用,而且有效期更长。     

肉桂醛替代保育猪饲粮中金霉素和杆菌肽锌

本试验研究了肉桂醛替代保育猪饲粮中金霉素和杆菌肽锌联用的效果。选取180头42日龄健康的杜×长×大三元杂交保育猪,按体重相似和性别比例相同原则将其分为对照组、试验A组和B组,每组60头猪,设4个重复,每个重复15头猪。对照组猪饲喂猪场现行的保育猪饲粮,其中含有金霉素、杆菌肽锌和黏杆菌素;将饲粮中金霉素和杆菌肽锌除去,分别添加400和600 mg/kg肉桂醛制剂,相应地饲喂试验A组和B组猪。试验期21 d。试验发现:用肉桂醛制剂替代保育猪饲粮中联用的金霉素和杆菌肽锌,可显著降低保育猪的腹泻率和腹泻指数(P0.05)。试验A组、B组猪平均日增重较对照组高,其中试验B组达到显著水平(P0.05)。试验B组猪血清总蛋白含量显著高于对照组(P0.05);试验组猪血清谷丙转氨酶活性低于对照组,其中试验B组达到显著水平(P0.05);试验B组猪血清谷草转氨酶活性显著高于对照组和试验A组(P0.05);试验A组、B组猪血清超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶活性和总抗氧化能力显著(P0.05)或极显著(P0.01)高于对照组;试验A组、B组猪血清丙二醛含量极显著低于对照组(P0.01)。试验A组、B组猪瘟抗体、蓝耳病抗体、圆环病毒抗体水平都显著地高于对照组(P0.05);猪伪狂犬抗体水平也呈上升趋势,其中试验B组达显著水平(P0.05)。3组猪血清口蹄疫抗体水平差异不显著(P0.05)。结果提示:肉桂醛能替代保育猪饲粮中联用的金霉素和杆菌肽锌,并且其应用效果比金霉素和杆菌肽锌联用的效果更好。肉桂醛能较好地预防和控制保育猪腹泻的发生,增强猪体抗氧化能力,促进保育猪的生长,提高饲料转化率。肉桂醛制剂在保育猪饲粮中适宜添加量为600 mg/kg。     

蓝茎冰草种子产量与施氮量和密度互作的模型分析

通过3因素5水平二次通用正交旋转组合设计方案,建立回归模型,进行解析、寻优和频数分析。结果表明:各试验因素对蓝茎冰草(Pascopyrum smithii)种子产量影响的大小顺序为施氮量(X₂)>植株密度(X₁)>喷施PP 333(X₃);施氮量与植株密度的互作效应对种子产量的作用为协同效应;同时得出了3因素对种子产量的优化配比方案:植株密度429.4~450×10⁴株/hm²,施氮量160~164.9kg/hm²,喷施PP 333量0.197~0.233 a.i.kg/hm²。