真桑钝绥螨捕食朱砂叶螨的实验种群生命表及捕食作用

为评价真桑钝绥螨Amblyseius makuwa Ehara防治害螨的可能性,本试验在(25±1)℃、RH 80%±5%、光周期16L:8D的条件下,组建了真桑钝绥螨以朱砂叶螨Tetranychus cinnabarinus Boisduv为食的实验种群生命表,研究了真桑钝绥螨雌成螨对朱砂叶螨卵、若螨和雌成螨的捕食作用。结果表明,真桑钝绥螨以朱砂叶螨为食,未成熟期发育历期分别为卵期1.90 d,幼螨期0.62 d,前若螨期0.82 d,后若螨期1.26 d。试验条件下真桑钝绥螨净增殖率为11.80,内禀增长率为0.175,世代平均周期为14.12 d,周限增长率为1.191,种群倍增时间为3.96 d,雌成螨日均产卵量为1.22粒,平均总产卵量为22.12粒。真桑钝绥螨对朱砂叶螨3个螨态的捕食功能反应均属于HollingⅡ型圆盘方程,拟合圆盘方程显示真桑钝绥螨对朱砂叶螨卵的捕食数量最大,其次为若螨和雌成螨,a/Th值分别为12.5162、5.8730和4.4009。综上研究结果,真桑钝绥螨具备优良天敌的基本特性,是朱砂叶螨的潜在天敌之一。     

劳氏黏虫在4种寄主植物上的生长发育和繁殖

【目的】明确寄主植物对劳氏黏虫Leucania loreyi(Duponchel)生长发育和繁殖的影响。【方法】在温度(24±1)℃、湿度(75±5)%、光周期为12 h光∶12 h暗的室内条件下,分别以玉米、水稻、甘蔗和稗草叶片为寄主植物,观察劳氏黏虫各虫态发育历期、存活率、蛹质量、成虫繁殖力并计算生命表参数。【结果】劳氏黏虫幼虫历期取食玉米时间最短,为20.18 d,取食甘蔗时间最长,为25.24 d。非成虫期存活率在玉米上最高(68%),在稗草上最低(58%);雌成虫蛹质量以取食玉米的最高(32.43 mg),取食稗草的最低(22.61 mg);取食玉米的产卵量最多,单雌产卵量为1 019.42粒,取食甘蔗的产卵量最少,单雌产卵量为665.27粒。劳氏黏虫在玉米、水稻、甘蔗和稗草上的内禀增长率(rm)分别为0.13、0.12、0.10和0.10,净增殖率(R0)分别为226.54、211.48、153.71和171.85。【结论】在4种寄主植物中,玉米为劳氏黏虫最优寄主,其次是水稻,甘蔗和稗草可作为寄主或中间寄主。     

Biosolubilization of phosphorus from rock phosphate and other P fertilizers in response to phosphate solubilizing bacteria and poultry manure in a silt loam calcareous soil

‘Phosphate solubilizing bacteria' (PSBs) are able to release unavailable P from native and applied P sources into plant‐available soil pool through their solubilizing and acidifying effects. The effects of three indigenous and one exotic PSBs on P solubilization from different P sources, plant biomass production, and P‐uptake efficiency of maize (Zea mays L.) were examined in an incubation and greenhouse study. For incubation study, surface (0–15 cm) soil was collected from an arable field (Inceptisols) and amended with rock phosphate (RP), single superphosphate (SSP), poultry manure (PM), and RP+PM with and without PSBs. The amended soil was incubated in the control environment at 25 ± 2°C for a total of a 100‐d period to establish relative potential rate of P solubilization of added P sources. A complementary greenhouse experiment was conducted in pots by growing maize as a test crop. Growth characteristics, P‐uptake, and P‐utilization efficiency (PUE) were determined. Phosphate solubilizing bacteria generated a solubilization effect on different P sources by releasing more P into plant‐available soil pool, i.e., 14.0–18.3 µg g^?1 in RP, 5.0–9.9 µg g^?1 in SSP, 1.4–4.4 µg g^?1 in PM, and 4.5–7.8 µg g^?1 in RP+PM compared to their sole application without PSBs. The available P from inorganic SSP declined continuously from the mineral pool (after day 30) and at the end 40% of applied P was unaccounted for. However, P losses were reduced to 28 and 27% when PSBs (PSB₁ and PSB₃) were applied with superphosphate treatments. In the absence of PSBs, the recoveries of applied P (in soil) from RP, SSP, PM and RP+PM were 4, 25, 9, and 12%, respectively, those had been increased to 14, 30, 12 and 15% in the presence of PSBs. Similarly, the plant biomass in RP+PSBs treatments compared to the RP without PSBs increased between 12–30% in first sampling (30 DAG) and 13–30% in the second sampling (60 DAG). The P utilization efficiency (PUE) in plants supplemented with PSBs was 20–73% higher compared to those without PSBs. The detection of oxalic and gluconic acids in culture medium treated with PSBs (7.8–25.0 and 25–90 mg L^?1, respectively) confirmed the production of organic acids by the indigenous bacterial isolates. This study indicate that low P recovery both in plant and soil can likely be improved by using indigenous PSBs and organic amendment poultry manure, which allowed a more efficient capture of P released due to P solubilization.     

热应激对畜禽精液品质的影响及其营养调控的研究进展

热应激严重影响公畜的繁殖机能,显著降低种公畜的精液品质,从而影响受胎率。本文阐述了热应激条件下不同公畜精液品质的变化,以及热应激蛋白对畜禽抗应激机理的影响和缓解热应激的营养调控技术,为实际生产中如何缓解热应激、提高种公畜精液品质提供参考。     

植物提取物对家禽肠道健康的调控及其作用机制

植物提取物中的活性物质有黄酮类、植物精油、生物碱、茶多酚、皂苷和多糖等,这些活性物质在动物机体内具有抗菌、抗氧化、增强肠道免疫、促进消化酶分泌及改善肠道健康等多种生理功能,且具有无残留和无耐药性等特点,是抗生素的理想替代品之一。本文借鉴国内外学者近年来的植物提取物在家禽肠道健康调控方面的研究成果,对植物提取物的抑菌活性成分及抗菌机制进行了概括和阐述,重点综述了植物提取物对家禽肠道消化生理、肠道发育及黏膜形态、肠道菌群、肠道免疫和肠道有害代谢产物的影响及其作用机制,以期为今后在家禽生产中合理使用植物提取物提供科学依据。     

规模化鸡场饮水系统添加微酸性电解水杀菌效果试验

重视饮水系统卫生质量安全是预防鸡群发病的一个重要环节.规模化鸡场饮水管道全封闭、内部清洁困难,而为提高饲料转化率和抗应激能力,普遍通过饮水系统添加多维等产品,加速了饮水系统污染、细菌超标等.目前鸡场饮水系统常用的反向冲洗水线、清洁剂洗涤清洁方式,存在杀菌不彻底、影响蛋鸡肠道微生物和废水过度排放等严重问题.该文研究了添加多维溶液对水线内水质影响变化规律,并对比研究了添加多维溶液后,冲洗水线、添加微酸性电解水2种方式对鸡场饮水系统的杀菌规律.结果表明:饮水系统中添加多维溶液2、4、6、12、24、36、48、72 h后,水线内细菌浓度总数的对数值分别增加9.96％、5.33％、6.04％、7.47％、4.98％、5.69％、4.27％、4.98％;冲洗水线能冲洗掉饮水管壁附着沉积层,一定程度上减少饮水中细菌总数,但饮水中细菌浓度总数仍高于中国饮水卫生质量标准;添加余氯0.3 mg/L的微酸性电解水24 h后,饮水管线中细菌浓度降低34.7％,48 h后水线中细菌浓度的对数值维持为(1.83±0.05 lg(CFU/mL)),添加余氯0.3 mg/L微酸性电解水使水线内细菌浓度总数显著降低(P＜0.01),达到中国饮水卫生标准,且规模化鸡场饮水系统添加微酸性电解水作为杀菌消毒剂可减少废水产生排放.该研究结果为鸡场饮水系统选择长期添加使用的消毒剂提供了参考依据.     

Correlation between the proportion of stained eggs and the number of mites (Dermanyssus gallinae) monitored using a ‘non‐parallel board trap’

The poultry red mite (Dermanyssus gallinae) is a serious problem for the poultry industry worldwide. However, the relationship between the mite population and the damage that they cause is still unclear. In this study, the mite population in poultry houses was examined using an established trap method, and the risk of blood‐stained eggs caused by the mites was assessed. Traps were placed once a week outside the egg channels and/or on the floor in two poultry farms in Fukuoka Prefecture, Japan, from April 2012 to July 2014. The numbers of blood‐stained eggs and total eggs were counted at weekly intervals. The results showed that the number of mites increased from April to May, and reached a peak around the beginning of June when the average temperature and humidity were >24°C and 70–90%, respectively. In the segmented model, the correlation between the proportion of blood‐stained eggs and the number of mites or temperature was positive over a threshold. In conclusion, our established trap method is useful for monitoring mites and can be used to predict when poultry farms should be treated to prevent appearance of blood‐stained eggs.     

Influence of Soil Properties and Manure Sources on Phosphorus in Runoff during Simulated Rainfall

Runoff from agricultural fields amended with animal manure or fertilizer is a source of phosphorus (P) pollution to surface waters, which can have harmful effects such as eutrophication. The objectives of this study were to evaluate the impact of soil P status and the P composition of manure sources on P in runoff and characterize the effects of manure sources on mass loss of dissolved reactive P, total dissolved P, and total P in runoff. Soil boxes set at 5% slopes received 7.5 cm h^?1 of simulated rainfall for 30 min. Study soils included a Kenansville loamy sand (loamy siliceous subactive thermic Arenic Hapludults, a Coastal Plain soil) and a Davidson silt loam (kaolinitic thermic Rhodic Kandiudults, a Piedmont soil). Soil test P concentrations ranged from 16 to 283 mg P kg^?1. Sources of P included broiler litter, breeder manure, and breeder manure treated with three rates of aluminum sulfate (Al₂(SO₄)₃) 0, 3.9, and 7.8 kg m^?2, di-ammonium phosphate (DAP), and an un-amended control. All manure sources were surface applied at 66 kg P ha^?1 without incorporation. Water extractable P represented an average of 10 ± 6% total P in manure. Runoff samples were taken over a 30-min period. Piedmont soil contained greater amounts of clay, aluminum (Al), and iron (Fe) concentrations, and higher P sorption capacities that produced significantly lower dissolved reactive P, total dissolved P, and total P losses than the Coastal Plain soil. Runoff P loss did not differ significantly for low and high STP Coastal Plain soils. Water extractable P in manures accounted for all dissolved reactive P lost in runoff with dissolved reactive P correlating strongly with water extractable P concentration (r² = 0.9961). Overall, manures containing the highest water extractable P concentrations contributed to the largest amounts of dissolved reactive P in runoff. Manure treated with 3.9 and 7.8 kg m^?2 of Al₂(SO₄)₃ (alum) decreased dissolved reactive P in runoff by 29%. While this soil box runoff study represents a worst-case scenario for P loss, highly significant effects of soil properties and manure sources were obtained. Management based on these results should help ameliorate harmful effects of P in runoff.     

半胱胺对家禽的影响

半胱胺是广泛存在于动物体内的生物活性物质,具有多种生物学功能。本文就半胱胺的理化性质和对家禽的影响进行了综述,旨在为家禽生产提供理论指导和实践帮助。     

黄芪多糖对家禽病毒性疾病的防治作用

黄芪多糖(APS)作为免疫增强剂对引起禽类疾病的多种病毒均有不同程度的抑制作用,这有效地提高了禽类的抗病能力和生产性能。同时,黄芪多糖具有毒副作用小、无残留、不产生耐药性等优点,因而具有广阔的应用前景。