利用“速服宁”进行种鸡场禽沙门氏杆菌病净化的初步研究

为对沙门氏菌及对产蛋率受精率控制,进行服用速服宁对鸡群的平板血检白痢阳性、产蛋率、死胚率检测试验,结果表明,使用速服宁可以控制减少鸡场禽沙门氏菌,鸡白痢阳性鸡转阴效果好,种鸡可再一次使用,鸡产蛋率和受精率也得到很大提高。     

提高小麦单产的田间排水暗管规格模拟

改进内蒙古河套灌区田间排水系统的规格对灌区提升作物产量和保障粮食生产有重要现实意义,因此,在河套灌区对所构建的分布式SWAP-WOFOST模型进行了参数率定和验证,然后,对2000—2010年灌区春小麦种植条件下适宜的田间排水暗管规格进行探讨,并模拟评价了该条件下作物产量和水分生产力(WP)的时空分布特征。结果表明,所构建的分布式模型在河套灌区具有较高的适应性。春小麦种植条件下,灌区大部分耕地面积推荐采用田间排水暗管的规格为间距100.0m或75.0m,埋深为2.5m。相比现有排水系统,采用推荐的排水暗管规格,春小麦多年平均作物产量提高了18.5%,多年平均WP提高5.2%。研究结果为进一步改进灌区田间排水系统的效果提供了一定的参考。     

春季施肥对多花黑麦草种子生产性能的影响

采用完全随机试验设计,研究了多花黑麦草Lolium multiflorum春季不同时期(分蘖期、拔节期和孕穗期)、不同施肥量对其种子生产性能的影响,结果表明,各处理对种子产量的影响极显著(P<0.01),处理B2[拔节期施肥N∶P∶K=20∶18∶22.5(kg/hm2)]种子产量最高,达到620.1 kg/hm2,比对照增产48.7%。与对照相比,千粒重和小穗数均显著增加。     

白三叶与不同禾草混播群落17年稳定性经较研究

在适度放牧条件下开展了白三叶与多年生黑麦草、紫羊茅、草地早熟禾和无芒雀麦的两两豆禾混播群落的种间相容性、群落生产力和稳定性的研究。17年的研究结果表明,白三叶 紫羊茅组合的年均干物质产量502g/m2,显著高于其他组合(P<0.05),但前期以白三叶 多年生黑麦草最高(P<0.05)。在时间序列混播比例的变化上,白三叶逐渐增加,然后维持在一定的范围;多年生黑麦草第1年最高,后逐渐下降;紫羊茅和草地早熟禾变化不大,而无芒雀麦减少最快,并最终消失;白三叶 紫羊茅组合的比例动态变化最小,组分稳定,而且群落抵抗力最强,年均杂草侵入量仅为2.4 g/m2,极显著地低于其他处理(P<0.01)。参试禾本科牧草与白三叶的种间相容性为紫羊茅>多年生黑麦草≥草地早熟禾>无芒雀麦。种间相容性是混播群落长期稳定性的重要决定因素。时间梯度上的群落生产力变化趋势,白三叶 紫羊茅和白三叶 草地早熟禾呈平稳略升,而白三叶 多年生黑麦草和白三叶 无芒雀麦呈前高后低模式。对混播群落稳定性的判断存在时间尺度和空间尺度。     

Protective effect of butylated hydroxylanisole against hydrogen peroxide-induced apoptosis in primary cultured mouse hepatocytes

Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H₂O₂)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H₂O₂ in a dose-dependent manner. Additionally, H₂O₂ treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H₂O₂ significantly attenuated the H₂O₂-induced decrease of cell viability. H₂O₂ exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H₂O₂-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H₂O₂-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H₂O₂-induced apoptosis by inhibiting ROS generation.     

Evaluation of embryonic age and the effects of different proteases on the isolation and primary culture of chicken intestinal epithelial cells in vitro

The present study evaluates the effects of embryonic age and proteolytic enzymes on the isolation and primary culture of chicken enterocyte and to establish an effective technique for chicken intestinal epithelial cell (IEC) cultivation. Fourteen‐day‐old, 16‐day‐old and 18‐day‐old embryos (average weight: 52.23 ± 0.76 g, 50.86 ± 0.99 g, 48.98 ± 1.03 g) were the source for preparation of enterocyte culture, and trypsin‐ethylene diamine tetraacetic acid, collagenase, thermolysin and combination of collagenase and thermolysin were used for digestion medium. Optimal culture protocols were determined by qualitative assays of proliferation. Cells isolated by using 14‐day‐old embryo and collagenase obtain the best attachment and growth in culture, and the production of continuously growing IEC cultures. Thus, we conclude that the use of collagenase as a dissociating enzyme and 14‐day‐old embryo as a source can be advantageously applied to the isolation of chicken IEC and this method may be useful for various applications and basic studies of the intestinal tract concerning such objects as physiology, immunology and toxicology.     

基于 DEA 和 Malmquist 指数的广东省渔业效率研究

【目的】分析掌握广东渔业的产出效率,为发展可持续的低耗高产渔业提供数据参考。【方法】基于数据包络分析（DEA）及 Malmquist 指数,对 2011—2022 年期间广东渔业综合技术效率和全要素生产率指数及其分解进行测算和分析,并与全国平均值进行对比。【结果】广东渔业综合技术效率每年均高于全国平均水平,但2011—2014 年、2018—2019 年和 2021 年广东渔业规模报酬呈现递减。通过对广东水产养殖和水产品捕捞的综合技术效率分别进行测算,发现 2011—2022 年期间广东水产养殖的综合技术效率较高,除 2013 年和 2014 年外,均为DEA 有效。将 DEA 无效年份的广东水产养殖和水产品捕捞在生产前沿面上的投影调整为 DEA 有效,结果显示,2013 年和 2014 年广东水产养殖投入的冗余率分别为 5.98% 和 10.46%,而 2011—2014 年、2018—2019 年和 2021年广东水产品捕捞投入的冗余率在 39.73%~74.27% 之间,说明水产品捕捞的过度投入以及由此引发的捕捞综合技术效率低下是造成 2011—2014 年、2018—2019 年和 2021 年广东渔业规模报酬递减的主要原因。广东渔业的技术进步和全要素生产率上升幅度与全国平均水平相差较远,全要素生产率和技术进步指数均比全国平均增幅低 4.7%,说明广东省在渔业技术进步方面有较大提升空间。【结论】建议广东加大渔业科技的投入力度,加强渔业技术创新,以促进渔业技术进步和提高全要素生产率;加快渔业产业结构调整,合理布局养殖和捕捞规模,以解决广东渔业规模报酬递减的问题;加强渔业资源保护和增殖放流,利用自然生产力增加可捕捞渔业资源;加强水产良种创制及养殖新模式和新技术的开发,进一步拓展水产养殖空间和提高水产养殖的产出效率。     

刈割强度对大针茅草原植物群落特征和土壤理化性质的影响

探究不同刈割强度对大针茅典型草原植物群落特征以及土壤理化性质的影响,可为大针茅草原制定合理科学的刈割制度提供理论依据。本研究以大针茅典型草原为对象,于2020年在内蒙古锡林浩特市毛登牧场刈割实验平台进行野外植被调查和取样。该实验平台于2014年建立,以不刈割为对照（CK）,设置轻度（LM）、中度（MM）及重度刈割（HM）3个处理。本研究通过计算物种重要值和多样性指数,测定植物群落地上、地下生物量以及土壤理化性质,探究群落特征与土壤理化性质的关系。结果表明：1）与不刈割相比,不同刈割强度均增加了新物种,且中度刈割的物种数最多;与不刈割相比,不同刈割强度均显著增加了群落的丰富度和Shannon-Wiener指数,且轻度刈割显著增加了优势度和均匀度指数,表明轻度刈割最有利于群落多样性的维持;不同刈割强度对大针茅草原的生产力均无显著影响;2）土壤全碳、全氮和pH均在中度刈割时最高,且显著高于不刈割,表明中度刈割对土壤养分有积极影响;3）硝态氮是影响草地生产力的主要土壤因子,土壤含水量是影响草地群落多样性的主要土壤因子。本研究可为大针茅典型草原群落结构、物种多样性以及生产力等方面的研究提供重要参...     

Responses in gross primary production of Stipa krylovii and Allium polyrhizum to a temporal rainfall in a temperate grassland of Inner Mongolia,China

In the arid and semi-arid areas of China, rainfall and drought affect the growth and photosynthetic activities of plants. Gross primary productivity (GPP) is one of the most important indices that measure the photosynthetic ability of plants. This paper focused on the GPP of two representative grassland species (Stipa krylovii Roshev. and Allium polyrhizum Turcz. ex Regel) to demonstrate the effect of a temporal rainfall on the two species. Our research was conducted in a temperate grassland in New Barag Right Banner, Hulun Buir City, Inner Mongolia Autonomous Region of China, in a dry year 2015. We measured net ecosystem productivity (NEP) and ecosystem respiration flux (ER) using a transparent chamber system and monitored the photosynthetically active radiation (PAR), air and soil temperature and humidity simultaneously. Based on the measured values of NEP and ER, we calculated the GPP of the two species before and after the rainfall. The saturated GPP per aboveground biomass (GPP_AGB) of A. polyrhizum remarkably increased from 0.033 (±0.018) to 0.185 (±0.055) μmol CO₂/(gdw?s) by 5.6-fold and that of S. krylovii decreased from 0.068 (±0.021) to 0.034 (±0.011) μmol CO₂/(gdw?s) by 0.5-fold on the 1^st and 2^nd d after a 9.1 mm rainfall event compared to the values before the rainfall at low temperatures below 35°C. However, on the 1^st and 2^nd d after the rainfall, both of the saturated GPP_AGB values of S. krylovii and A. polyrhizum were significantly lower at high temperatures above 35°C (0.018 (±0.007) and 0.110 (±0.061) μmol CO₂/(gdw?s), respectively) than at low temperatures below 35°C (0.034 (±0.011) and 0.185 (±0.055) μmol CO₂/(gdw?s), respectively). The results showed that the GPP responses to the temporal rainfall differed between S. krylovii and A. polyrhizum and strongly negative influenced by temperature. The temporal rainfall seems to be more effective on the GPP of A. polyrhizum than S. krylovii. These differences might be related to the different physiological and structural features, the coexistence of the species and their species-specific survival strategies.     

Habitat configuration for an obligate shallow‐water delphinid: The Indo‐Pacific humpback dolphin,Sousa chinensis,in the Beibu Gulf (Gulf of Tonkin)

1. Habitat configuration is an important baseline to delineate protected area design, refine impact mitigation measures and define habitat protection plans for threatened species. For coastal delphinids, outlining their habitat configuration becomes a real challenge when faced with large distribution ranges that straddle international borders, leaving broad information gaps in uninvestigated areas.
2. This study projected likely habitats of Indo‐Pacific humpback dolphins, Sousa chinensis, in the Beibu Gulf (Gulf of Tonkin) based on occurrence data and remotely sensed oceanographic characteristics. Net primary productivity was derived to measure the ecosystem service of humpback dolphin habitats.
3. Bathymetry and chlorophyll‐a concentration are major variables contributing to humpback dolphin habitat configuration, which is characterized by shallow water depth and high primary productivity. Three major, likely habitats were identified in the northern Beibu Gulf from western Leizhou Peninsula to the China–Vietnam border, western Gulf of Tonkin from the Red River estuary to the central coast of Vietnam, and south‐western Hainan Island. Less than 9% of likely habitats are currently protected by marine protected areas.
4. Affinity to high primary productivity and shallow depths implies that prey abundance and foraging efficiency influence habitat selection by Indo‐Pacific humpback dolphins. Anthropogenic activities potentially altering oceanographic characteristics may impact regional marine ecosystem functions, and hence habitat configuration.
5. Habitat protection actions for Indo‐Pacific humpback dolphins include implementing coordinated and systematic surveys in major habitats, associating core habitat protection with protected area networks and maritime function zoning, ensuring ecosystem function integrity within major habitats, and reducing both explicit lethal impacts and implicit anthropogenic impacts from activities that change oceanographic features. The habitat protection plan should not only consider marine habitats, but also adjacent coastal landscapes and river catchments. This requires coordination, collaboration and information sharing between scientific research teams, government policy representatives, non‐governmental organizations, local communities and other interested stakeholders.