新疆冬季密闭羊舍的空气质量分析

对一栋密闭式羊舍内的空气质量进行了观测及分析,结果表明:在舍内0.6m、1.6m和3.0m的不同高度层中,氨气的平均浓度分别35.0mg/m3、36.7mg/m3和44.2 mg/m3,其中3.0m显著高于0.6m、1.6m(P<0.05),0.6m、1.6m之间差异不显著(P>0.05);硫化氢的平均浓度分别为0.0039mg/m30、.0027 mg/m3和0.0030mg/m3,各层浓度间差异均不显著(P>0.05);二氧化碳的平均浓度分别为2571mg/m3、2593mg/m3和2581mg/m3,各层浓度间差异均不显著(P>0.05)。舍内NH3、H2S、CO2气体呈现一定的昼夜变化,三种气体白天的平均浓度均低于夜间。而舍内各环境因素之间存在一定的相关关系,其中温度高低对舍内NH3与CO2气体的含量有明显的影响,舍内空气湿度的变化对TSP、PM10的含量和粪便含水量对舍内NH3的含量亦有明显的影响,它们之间均存在显著的相关性。     

Quercetin attenuates H2O2‐induced toxicity of rooster semen during liquid storage at 4°C

Current study was carried out to examine the protective effects of quercetin against toxicity induced by hydrogen peroxide in rooster semen in vitro. Semen samples were collected from ten roosters (Ross 308 broiler breeder males, 32 weeks old) twice a week by abdominal massage method. Samples with ≥70% progressive motility were selected, pooled, diluted and used for the study. Experimental groups consisted of negative control, control that received solvent of quercetin, H₂O₂ (40 μM) and combination groups which incubated with constant dose of H₂O₂ (40 μM) plus various levels of quercetin (20, 40 and 80 μM). Measurement of total hydroperoxide (HPO), malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (TAC) and superoxide dismutase activity as well as routine sperm tests were done at 0, 24 and 48 hr of storage at 4°C. Results revealed that exposure to hydrogen peroxide significantly increased HPO (138.43 ± 7.32 vs. 66.08 ± 3.97 μmol/g protein), MDA (7.21 ± 0.08 vs. 5.71 ± 2.16 μmol/g protein) and NO (0.367 ± 0.013 vs. 0.215 ± 0.011 μmol/g protein) levels and decreased sperm progressive motility (27.28 ± 1.21 vs. 47.49 ± 1.29%), and amounts of TAC (11.49 ± 0.39 vs. 15.70 ± 0.79 mmol/g protein) compared to control at 24 hr (p < 0.05). Changes at mentioned variables were repeated at 48 hr of storage. Also, co‐administration of quercetin (especially at 40 and 80 μM) with hydrogen peroxide restored the toxic effects of hydrogen peroxide on rooster semen parameters such as primary and secondary lipid peroxidative indicators and other evaluated variables. The study concluded that rooster semen enrichment with quercetin would protect lipid peroxidative and nitrosative hydrogen peroxide‐mediated damage during cold liquid storage of rooster semen.     

Metabolite profiling of the response to high-nitrogen fertilizer during grain development of bread wheat (Triticum aestivum L.)

Wheat yield and quality are dependent largely on nitrogen (N) availability. In this study, we performed the first metabolomic analysis of the response to high-N fertilizer during wheat grain development using non-targeted gas chromatography-mass spectrometry (GC–MS). Quality parameter analyses demonstrated that high-N fertilizer application led to a significant increase in grain protein content and improvement in starch and bread-making quality. Comparative metabolomic profiling of six grain developmental stages resulted in identification of 74 metabolites, including amino acids, carbohydrates, organic acids and lipids/alcohol, which are primarily involved in carbon and N metabolism. Under high-N fertilizer treatment, numerous metabolites accumulated significantly during grain development. Principal component analysis revealed two principal components as being responsible for the variances resulting from N-fertilizer treatments. Metabolite–metabolite correlation analysis demonstrated that the high-N treatment group had a greater number of positive correlations among metabolites, suggesting that high-N fertilizer treatment induced a concerted metabolic change that resulted in improved grain development. Particularly, the high-N treatment-mediated significant accumulation of metabolites involved in the TCA cycle, starch and storage protein synthesis could be responsible for the improvement of grain yield and quality. Our results provide new insight into the molecular mechanisms of wheat grain development and yield and quality.     

Abscisic acid alleviates the deleterious effects of cold stress on ‘Sultana’ grapevine (Vitis vinifera L.) plants by improving the anti-oxidant activity and photosynthetic capacity of leaves

The effects of exogenous application of abscisic acid (ABA) on anti-oxidant enzyme activities and photosynthetic capacity in ‘Sultana’ grapevine (Vitis vinifera L.) were investigated under cold stress. When vines had an average of 15 leaves, 0 (control), 50, 100, or 200 µM ABA was sprayed to run-off on all leaves of each plant. Twenty-four hours after foliar spraying with ABA, half (n = 5) of the water-only control vines and half (n = 5) of each group of ABA-treated plants were subjected to 4°C for 12 h, followed by a recovery period of 3 d under greenhouse conditions (25°/18°C day/night). The remaining plants in each treatment group were kept at 24°C. Cold stress increased H₂O₂ and malondialdehyde (MDA) concentrations in vine leaves, whereas all foliar ABA treatments significantly reduced their levels. Chilled plants showed marked increases in their total soluble protein contents in response to each ABA treatment. ABA significantly increased the activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase in cold-stressed grapevine leaves. In contrast, cold stress markedly decreased the rates of leaf photosynthesis (A) and evaporation (E), stomatal conductance (g_s), and chlorophyll concentrations in leaves, but increased intercellular CO₂ concentrations (C_i) in leaves. Treatment with all concentrations of ABA resulted in lower leaf A, E, and g_s values, but higher C_i values at 24°C. However, following cold stress, ABA-treated vines showed higher leaf A, E, and g_s values, but lower C_i values compared to control vines without ABA treatment. The application of 50–200 µM ABA allowed chilled vines to recover more quickly when re-exposed to normal temperatures, enabling the vines to resume their photosynthetic capacity more efficiently following cold stress. These results showed that, by stimulating anti-oxidant enzyme systems and alleviating cold-induced stomatal limitations, ABA reduced the inhibitory effect of cold stress on the rate of CO₂ fixation in ‘Sultana’ grapevine plants.     

离子束修饰提高钛阴极析氢活性

研究了双重离子注入Ｗ＾＋／Ｎｉ＾＋,Ｗ＾＋／Ｍｏ＾＋及溅射Ｆｅ后再单离子注入Ｃｏ＾＋或Ｗ＾＋等离子束修饰的钛电极在１ＮＨ２ＳＯ４中的析氢电催化性能,结果表明：与纯钛电极相比,离子束修饰电极的催化析氢活性得到显著改善,其中,注Ｗ＾＋／Ｎｉ＾＋电极的析氢过电位降低３００ｍＶ,用ＸＰＳ和ＡＥＳ能谱分析了离子束修饰电极的表面元素及相结构,讨论了修饰电极催化所氢机理。     

日粮中纳豆芽孢杆菌对体外猪粪发酵液中臭气及微生物的影响

为了减少舍外粪便污染,研究日粮中纳豆芽孢杆菌对体外猪粪发酵液中氨气、硫化氢、粪臭素及菌群的影响。试验组生猪饲喂纳豆芽孢杆菌日粮,对照组无纳豆芽孢杆菌。结果表明,试验组氨气、硫化氢、色氨酸、吲哚-3-乙酸、粪臭素浓度极显著低于对照组(P0.01),吲哚显著低于对照组(P0.05)。对照组猪粪发酵液优势菌以芽孢杆菌(CWBI B1434)为主,含量为26%;试验组以非解乳糖链球菌(AF201899)为主,含量为36%,其次为噬淀粉乳酸杆菌,含量为16%。结果表明纳豆芽孢杆菌通过调整猪粪菌群降低臭味物质浓度。为了减少舍外粪便污染,建议猪日粮中添加纳豆芽孢杆菌。     

O3与O3/H2O2两个体系降解除草剂2,4-D反应特性研究

分别采用O3、O3/H2O2体系降解苯氧羧酸类除草剂2,4-D,探讨了降解过程中反应温度、pH值、O3混合气流量、有机物初始浓度等操作条件的变化对降解动力学的影响。结果发现,温度和pH值的影响较大,O3流量影响最小,温度升高、pH值增大、臭氧流量增加、2,4-D初始浓度降低均有助于降解速率的提高。O3/H2O2体系中,H2O2能促进O3分解产生大量自由基,导致2,4-D反应活化能降低。和O3相比,O3/H2O2体系降解效果好,降解时间短,反应条件温和,操作费用低,是很有发展前景的高级氧化技术。     

EGR与富氢进气对柴油机性能和排放的影响

试验研究了利用EGR加富氢进气改善ZS195型柴油机性能和排放的可行性,在标定转速下试验研究了不同EGR率、掺氢率对ZS195型柴油机工作过程、排放和经济特性的影响.研究结果表明:在高负荷工况,当EGR率一定时,随着掺氢率的增加,缸内峰值压力和压力升高率峰值增加.EGR加富氢进气可以降低HC、CO排放量和烟度,但NO_x排放量有所增加.ZS195型柴油机采用EGR技术后,富氢进气会提高缸内混合气的燃烧速度,改善缸内燃烧质量,发动机的热效率有所增加.     

Degradation and effect of hydrogen peroxide in small‐scale recirculation aquaculture system biofilters

From an environmental point of view, hydrogen peroxide (HP) has beneficial attributes compared with other disinfectants in terms of its ready degradation and neutral by‐products. The rapid degradation of HP can, however, cause difficulties with regard to safe and efficient water treatment when applied in different systems. In this study, we investigated the degradation kinetics of HP in biofilters from water recirculating aquaculture systems (RAS). The potential effect of HP on the nitrification process in the biofilters was also examined. Biofilter elements from two different pilot‐scale RAS were exposed to various HP treatments in batch experiments, and the HP concentration was found to follow an exponential decay. The biofilter ammonia and nitrite oxidation processes showed quick recuperation after exposure to a single dose of HP up to 30 mg L^?1. An average HP concentration of 10–13 mg L^?1 maintained over 3 h had a moderate inhibitory effect on the biofilter elements from one of the RAS with relatively high organic loading, while the nitrification was severely inhibited in the pilot‐scale biofilters from the other RAS with a relatively low organic loading. A pilot‐scale RAS, equipped with two biofilter units, both a moving‐bed (Biomedia) and a fixed‐bed (BIO‐BLOK^®) biofilter, was subjected to an average HP concentration of ～12 mg L^?1 for 3 h. The ammonium‐ and nitrite‐degrading efficiencies of both the Biomedia and the BIO‐BLOK^® filters were drastically reduced. The filters had not reverted to pre‐HP exposure efficiency after 24 h, suggesting a possible long‐term impact on the biofilters.     

The interaction between temperature and dose on the efficacy and biochemical response of Atlantic salmon to hydrogen peroxide treatment for amoebic gill disease

Hydrogen peroxide (H₂O₂) is a commonly used treatment for a range of parasitic diseases of marine finfish, including amoebic gill disease (AGD). While this treatment is partially effective at reducing parasite load, H₂O₂ can have detrimental effects on the host under certain conditions. Treatment temperature and dose concentration are two factors that are known to influence the toxicity of H₂O₂; however, their impact on the outcome of AGD treatment remains unclear. Here, we investigated the effects of treatment temperature (8, 12 or 16°C) and dose concentration (750, 1,000, 1,250 mg/L) on the efficacy of H₂O₂ to treat AGD. We demonstrated that a 20-min bath treatment of H₂O₂ at all doses reduced both parasite load and gross gill score significantly. Parasite load and gross gill score were lowest in the 1,000 mg/L treatment performed at 12°C. At the high dose and temperature combinations, H₂O₂ caused moderate gill damage and a significant increase in the plasma concentration of electrolytes (sodium, chloride and potassium). Taken together, our study demonstrates that higher H₂O₂ treatment temperatures can adversely affect the host and do not improve the effectiveness of the treatment.