我国常见木本植物的含碳率

根据国内研究成果,收集了100多个乔、灌木的含碳率数据。     

不同处理方法对和田苜蓿种子发芽率的影响

[目的]寻找一种能有效提高和田苜蓿种子发芽率的方法。[方法]通过采取热水浸泡处理、98%浓硫酸浸泡处理、100 g/L硝酸钾浸泡处理、磨擦种皮结合热水浸泡处理、30%双氧水浸泡处理等5种不同方法处理和田苜蓿种子,观察测定并研究以上5种处理方法对和田苜蓿种子发芽势、发芽率、发芽指数及活力指数的影响。[结果]以磨擦种皮结合25℃热水浸泡30 min处理对和田苜蓿种子发芽率具有明显的效果,可达到81.3%;其次是100 g/L硝酸钾浸种2 h、50℃热水浸泡处理和30%双氧水浸种5 min;用98%浓硫酸处理的效果较差。[结论]磨擦种皮结合25℃热水浸泡30 min处理是提高和田苜蓿种子发芽率的最佳方法。     

提高农机年检审率的方法

农机安全监理部门应当调整工作思路,切实做好农机年检审率,为农机安全生产提供保障。     

添加松针粉对肉鸡营养物质代谢率的影响

选用18日龄肉鸡80羽,随机分为4组,分别为组Ⅰ、组Ⅱ、组Ⅲ、组Ⅳ,其中组Ⅰ、组Ⅱ、组Ⅲ为试验组,组Ⅳ为对照组。每组5个重复,每个重复4羽(♀)。采用单因子随机分组设计,共设4个处理,组Ⅰ为基础饲料+1%松针粉,组Ⅱ为基础饲料+3%松针粉,组Ⅲ为基础饲料+5%松针粉,对照组为基础饲料+抗生素。研究结果表明,干物质表观代谢率组Ⅰ、组Ⅱ与对照组之间无显著性显著(P>0.05),但组Ⅲ干物质表观代谢率显著低于对照组(P<0.05),5%松针粉组干物质代谢率比对照组低5.46%,其余各组间无显著性差异(P>0.05);粗蛋白质日摄入量及日排出量各组间均无显著性差异(P>0.05);粗蛋白质表观代谢率组Ⅰ、组Ⅱ、组Ⅲ显著高于对照组(P<0.05),组Ⅰ、组Ⅱ、组Ⅲ分别比对照组提高了18.34%、23.44%、27.13%;粗脂肪日摄入量组Ⅲ显著高于组Ⅰ和对照组(P<0.05),试验组之间无显著性差异(P<0.05);粗脂肪日排出量组Ⅲ显著高于组Ⅰ、组Ⅱ及对照组(P<0.05),其余各组间无显著性差异(P>0.05);粗脂肪的表观代谢率组Ⅰ、组Ⅱ显著高于对照组(P<0.05),其余各组间无显著性差异(P>0.05),粗脂肪的表观代谢率组Ⅰ、组Ⅱ、组Ⅲ分别比对照组提高了6.86%、9.43%、5.05%;磷的日摄入量、日排出量、表观代谢率各组间无显著性差异(P>0.05)。     

Effects of feed processing conditions and acid salts on nutrient digestibility and physical quality of soy‐based diets for Atlantic salmon (Salmo salar)

Two experiments were conducted to investigate effects of feed processing conditions and potassium diformate (KDF) supplementation on apparent digestibility of nutrients in Atlantic salmon (Salmo salar) and physical quality of extruded feed. In Exp. 1, diets with raw or expander pretreated full‐fat soybean meal (FFSBM) at 100 or 120 °C were extruded at 110 °C. Expander pretreatment significantly (P < 0.05) improved the digestibility of arginine, glutamine and tyrosine in Atlantic salmon. The higher digestibility of expander pretreated FFSBM was confirmed in mink (Mustela vison). In Exp. 2, diets with defatted soybean meal (SBM) were extruded at 110, 130 or 150 °C. The results showed that increasing extrusion temperatures significantly (P < 0.05) improved the digestibility of most major nutrients and amino acids in Atlantic salmon. In general, KDF supplementation to FFSBM and SBM diets did not affect digestibility of nutrients in Atlantic salmon or mink. Expander pretreatment and increasing extrusion temperatures increased pellet expansion, while KDF supplementation reduced pellet expansion.     

Hatch rate of channel catfish Ictalurus punctatus (Rafinesque 1818) eggs treated with 100 mg L−1 copper sulphate pentahydrate

Catfish hatcheries use copper sulphate pentahydrate (CuSO₄·5H₂O) as an economical control for saprolegniasis on eggs. This study determines hatch rate of channel catfish, Ictalurus punctatus (Rafinesque 1818), eggs in hatching troughs containing 23.8 °C flow‐through well water when treated with 100 mg L^?1 CuSO₄·5H₂O (10 times the proposed therapeutic dose). Eggs were treated daily until the embryos reached the eyed stage. Fry survival in the control and 100 mg L^?1 CuSO₄·5H₂O treatments was significantly different (15% and 71% respectively). This study demonstrates that there is a considerable margin of safety in using CuSO₄·5H₂O as a catfish egg treatment to control saprolegniasis.     

Combined effect of temperature,salinity and density on the growth and feed utilization of Nile tilapia juveniles (Oreochromis niloticus)

Based on Box–Behnken experimental design and response surface method, the joint effect of temperature (16–36°C), salinity (0–22 ppt) and rearing density (200–1000 fish.m^?3) on the specific growth rate (SGR) and feed conversion rate (FCR) of Nile tilapia juveniles were studied under laboratory conditions. The entire experiment lasted for 1 month (30 days). Results showed that the linear and quadratic effects of temperature, salinity on both growth and feed utilization were highly statistically significant (P < 0.01). The linear and quadratic effect of rearing density on the growth was highly significant (P < 0.01); the linear effect of rearing density on feed utilization was significant (P < 0.05), but the quadratic effect nonsignificant (P > 0.05). Interactions between temperature and salinity, and between salinity and rearing density on the growth statistically differed from zero (P < 0.05). Interactions between temperature and salinity, between temperature and density on feed utilization was significant (P < 0.05). Model equations of the growth and feed utilization on temperature, salinity and density were established, with the coefficient of determination being 98.34% for growth and 98.11% for feed utilization, and could be applied to projection. The optimal temperature/salinity/density combination was obtained utilizing statistical optimization approach: 29°C/6 ppt/500 fish.m^?3, at which the maximal specific growth and feed utilization reached 4.228%.d^?1 and 0.520 respectively, with the desirability being 0.989.     

全氟辛烷磺酸钾对真鲷谷胱甘肽质量分数和谷胱甘肽转硫酶活性的影响

为了解全氟辛烷磺酸钾（PFOS）对海洋鱼类抗氧化防御系统的毒性效应及致毒机理,在实验室条件下研究了PFOS胁迫和净水恢复过程中真鲷（Pagrosomus major）鳃组织和肝脏组织内谷胱甘肽（GSH）质量分数与谷胱甘肽转硫酶（GST）活性的变化。结果显示,胁迫开始时鳃中w（GSH）在低浓度组出现诱导,中、高浓度组出现抑制现象,随着胁迫时间的延长,各浓度组处于显著诱导水平（P〈0.01）;肝脏中w（GSH）在胁迫第15天时各浓度组中出现显著的剂量效应,w（GSH）随着PFOS曝露浓度的升高而降低。真鲷2种组织的GST活性变化与各自组织中w（GSH）的变化趋势相近。净水恢复期内个别浓度组的指标恢复到对照组水平,说明真鲷可以修复PFOS胁迫造成的损伤。结果表明,PFOS在试验条件下对真鲷有显著的毒性作用,可能对海洋高等生物存在潜在性危害,应对其海洋环境风险评价加以关注。     

西南大西洋阿根廷滑柔鱼耳石微结构及生长特性

根据我国鱿钓船2007、2008和2010年在西南大西洋作业期间采集的3462尾阿根廷滑柔鱼样本(其中2007年308尾、2008年262尾、2010年2 892尾),测量了491枚耳石外部形态参数和耳石重量(雌性274枚、雄性217枚),结合耳石的日轮,对耳石微结构及其生长特性进行了研究。结果表明,阿根廷滑柔鱼耳石的生长纹由明暗相间的环纹组成,耳石中心为黑色,呈水滴形;从核心到侧区边缘,轮纹宽度由窄至宽,亮度由明至暗;侧区到北区边缘,轮纹则由宽至窄,亮度由暗至明。根据生长纹的宽度和颜色的明暗,可将整个耳石分为3个区域,即后核心区、暗区、外围区。不同群体间耳石总长(TSL)和最大宽度(MW)的生长存在显著性差异,但性别间无差异。冬季产卵群TSL和MW的生长适合用线性函数表示,秋季产卵群则适合用对数函数表示。耳石重量(SW)的生长存在群体和性别间差异,冬季产卵群雌、雄个体SW的生长分别适合用幂函数和指数函数表示,秋季产卵群则分别适合用指数函数和对数函数表示。两个群体的TSL、MW、绝对生长率和相对生长率都随着日龄的增加而先增加后减小,而SW的绝对生长率则随着年龄增加而增加,相对生长率则随着年龄增加而先增加后减小。同一年龄段内冬季产卵群的绝对和相对生长率基本上都大于秋季产卵群,雌性个体的绝对和相对生长率要大于雄性个体。     

全雄奥利亚罗非鱼的制种与应用研究

为获得全雄奥利亚罗非鱼(Oreochromis aurea),对WZ♀-ZZ♂类型的奥利亚罗非鱼采用原系(ZZ♂)与转化系(ZZ△♀)二系配套技术,控制遗传全雄鱼的性别。根据泄殖器特征对转化后的实验鱼进行性別鉴定,确定性别。对实验鱼的外部形态、内部结构进行生物学描述。统计并观察实验鱼的雄性率、生长和发育状况。总结全雄奥利亚罗非鱼在应用中的优势,以期为奥利亚罗非鱼养殖业的发展指明方向。