黄瓜幼苗光合及荧光特性对弱光的响应

 以不耐弱光的‘津研2号’和较耐弱光的‘戴多星’黄瓜(Cucumis sativus L.)为试材,在人工气候室内研究其光合及荧光特性对弱光（75～85 μmol·m^-2·s^-1）的响应。结果表明,弱光处理后叶片光合色素含量、总叶绿素/类胡萝卜素比值呈增加趋势,尤其是戴多星更明显;叶绿素a/b比值呈减小趋势,且戴多星的减小幅度大于津研2号;净光合速率、水分利用效率呈下降趋势,戴多星下降幅度小于津研2号;叶片最大光化学效率、光系统Ⅱ实际光化学效率、光化学反应速率、光系统非环式电子传递速率、光系统Ⅱ吸收光能用于光化学反应的比例,对弱光的响应有一定差异,弱光下戴多星均有明显增加,而津研2号的增减不规律,且幅度均较小,说明弱光下戴多星对弱光的利用能力明显强于津研2号。     

培养条件对巨大口蘑菌丝生长的影响

研究了不同培养基配方、pH、温度对巨大口蘑（Tricholoma giganteum）菌丝生长的影响。结果表明,在实验培养基中,巨大口蘑菌丝生长的最佳培养基为加富PDA-4（马铃薯20％,葡萄糖2％,酵母粉0．5％,钙中盖0．3％,MgSO40．2％,琼脂2％）,巨大口蘑菌丝的生长速度较快,菌丝粗壮、浓白、致密;最适温度28～30℃,最适pH7．0。     

Occurrence of reproductive disorders in pig herds with and without Chlamydia suis infection – statistical analysis of breeding parameters

Chlamydiae are frequently encountered Gram‐negative intracellular eubacteria that can cause clear manifestations or clinically asymptomatic disorders. C. suis and other chlamydia are primarily isolated in cases of reproductive disorders. This study was performed to estimate the impact of Chlamydia suis infection on reproduction in sows by analyzing reproduction rates and breeding parameters. The test was conducted on first generation (F1) pigs from Polish Landrace (PL) × Polish Large White (PLW). Sixty‐four herds were investigated and 500 vaginal swabs were collected. Isolation of DNA was carried out directly from the swabs. All samples were analyzed for Chlamydia suis by real‐time PCR with a locked nucleic acid (LNA)‐containing probe. To analyze the impact of chlamydia infection on reproductive parameters, evaluation questionnaires were used. Reproductive problems were found in 77.3% of the farms tested. The receiver operating characteristic curve indicated that in the farms with 10 up to 120 sows, there were higher reproductive problems with chlamydia infection than in smaller and bigger pig farms. The most common problems were estrus repetition, which was reported by 57.81% of the surveyed farms, and the birth of dead piglets, which was reported by 31.25% of the investigated pig farms. Abortions, which were reported by 28.12% of the surveyed farms, were the least common reproductive disorders.     

Effects of different forage combinations in total mixed rations on in vitro gas production kinetics,ruminal and milk fatty acid profiles of lactating cows

This study aimed to determine the effects of different forage combinations on in vitro gas production (GP) kinetics, ruminal and milk fatty acid profiles. Forty‐five lactating cows were randomly arranged into three groups and fed three total mixed rations (TMRs) with different forage combinations: TMR1, 23% alfalfa hay, 7% Chinese wild ryegrass hay and 15% whole corn silage; TMR2, 30% corn stover plus 15% whole corn silage; TMR3, 30% rice straw plus 15% whole corn silage. In vitro dry matter disappearance ranked: TMR1 > TMR2 > TMR3, and highest cumulative GP and asymptotic GP occurred in TMR1 while no difference occurred between TMR2 and TMR3. The average GP rate ranked: TMR1 > TMR2 > TMR3. TMR1 in comparison with TMR2 and TMR3 presented lower rumen contents of acetate and butyrate and greater rumen contents of propionate, valerate, C13:0, C14:0, C15:0, C18:1cis‐9, C18:2n‐6, C18:3n‐3, C20:0 and C22:0 as well as milk C18:2n‐6 and C18:3n‐3 proportions. Transfer efficiencies of C18:2n‐6 and C18:3n‐3 from diet to milk ranked: TMR1 > TMR2 > TMR3. The findings suggest TMRs containing alfalfa hay and Chinese wild ryegrass hay in comparison with corn stover or rice straw improve rumen fermentation and transfer efficiency of C18:2n‐6 and C18:3n‐3.     

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.     

复合益生菌和纤维寡糖对断奶仔猪生长性能、粪便微生物及血清指标的影响

本试验旨在研究复合益生菌和纤维寡糖对断奶仔猪生长性能、粪便微生物及血清指标的影响。选用120头初始平均体重为(9.72±2.25)kg的断奶仔猪,随机分为4组,每组3个重复,每个重复10头。分别饲喂基础饲粮(对照组)、基础饲粮+0.30%复合益生菌(A组)、基础饲粮+0.08%纤维寡糖(B组)、基础饲粮+0.30%复合益生菌+0.08%纤维寡糖(C组),试验预试期4 d,正试期35 d,正试期分为第1阶段(1~14 d)和第2阶段(15~35 d)2个阶段。结果表明:1)除试验15~35 d时C组试验仔猪料重比(F/G)显著低于对照组外(P0.05),其余各阶段各组试验仔猪平均日采食量(ADFI)、平均日增重(ADG)、料重比均无显著差异(P0.05);试验1~14 d时A、C组试验仔猪腹泻率(DR)均显著低于对照组(P0.05)。2)试验第14、35天时各组试验仔猪粪便中芽孢杆菌数、乳酸菌数和大肠杆菌数均无显著差异(P0.05)。3)各组试验仔猪各项血清指标也均无显著差异(P0.05)。由此可见,本试验条件下,添加复合益生菌和纤维寡糖可改善断奶仔猪断奶后1~14 d的腹泻情况,提高断奶仔猪断奶后15~35d的饲料利用效率。     

植物乳杆菌和非淀粉多糖复合酶对断奶仔猪生长性能、粪便微生物菌群及血清指标的影响

本试验旨在研究饲粮中添加植物乳杆菌(Lactobacillus plantarum)和非淀粉多糖(NSP)复合酶对断奶仔猪生长性能、粪便微生物菌群及血清指标的影响,从而达到代替抗生素的目的。试验采用单因素完全随机设计,选择28日龄健康断奶仔猪192头,平均体重为(7.15±0.36)kg,随机分为4个组,每组6个重复,每个重复8头猪。对照组(CT组)饲喂在基础饲粮中添加40 mg/kg杆菌肽锌的饲粮;试验组分别饲喂在基础饲粮中添加1 g/kg植物乳杆菌(PT组)、1 g/kg NSP复合酶(ZT组)、1 g/kg植物乳杆菌+1 g/kg NSP复合酶(PZT组)的饲粮。试验期35 d。结果表明:1)各组间断奶仔猪的试验末重、平均日增重、平均日采食量及料重比均无显著差异(P0.05)。2)各组间断奶仔猪粪便中乳酸菌数量、大肠杆菌数量及乳酸菌/大肠杆菌均无显著差异(P0.05)。但与对照组相比,PZT组断奶仔猪粪便中乳酸菌数量和乳酸菌/大肠杆菌有增加趋势(0.05≤P0.10),大肠杆菌数量有降低趋势(0.05≤P0.10)。3)各组间断奶仔猪的血清生化指标、免疫指标均无显著差异(P0.05)。由此可知,饲粮中复合添加植物乳杆菌和NSP复合酶可促进肠道菌群平衡,有益于仔猪健康生长,从而达到替代抗生素的目的。     

秋冬季补光时间和强度对白羽王鸽产蛋性能、血清生理生化指标及抗氧化能力的影响

本试验旨在研究秋冬季不同补光时间和强度对白羽王鸽产蛋性能、血清生理生化指标及抗氧化能力的影响。试验将280只健康的8月龄白羽王鸽(全为母鸽)进行两两配对,共140对即140笼,并按体重相近的原则,随机分成5组,每组4个重复,每个重复7笼(14只)。各组补光时间和强度分别为:0 h、0 lx,4 h、31.2 lx,4 h、20.5 lx,6 h、31.2 lx,6 h、20.5 lx。试验期125 d。结果表明:1)4 h、20.5 lx,6 h、31.2 lx组产蛋率显著高于0 h、0 lx组(P0.05),各组平均日采食量、平均蛋重无显著差异(P0.05)。2)6 h、31.2 lx,6 h、20.5 lx组血清免疫球蛋白M含量显著低于0 h、0 lx组(P0.05)。4 h、31.2 lx,4 h、20.5 lx,6 h、31.2 lx和6 h、20.5 lx组血清谷草转氨酶活性均高于0 h、0 lx组(P0.05)。3)各组血清催乳素(PRL)、雌二醇(E2)、促卵泡激素、黄体生成素和孕酮含量无显著差异(P0.05),但0 h、0 lx组血清PRL含量高于其他各组,血清E2含量低于其他各组。4)与0 h、0 lx组相比,6 h、31.2 lx组血清超氧化物歧化物活性显著降低(P0.05),血清丙二醛(MDA)含量显著升高(P0.05)。0 h、0 lx,4 h、20.5 lx,6h、20.5 lx组肝脏MDA含量显著低于6 h、31.2 lx组(P0.05)。由此可见,补光时间和强度为4 h、20.5 lx时,白羽王鸽可获得较好的产蛋性能。补光时间过长(6 h)且强度过高(31.2 lx)可显著降低白羽王鸽抗氧化能力,补光强度应不超过20.5 lx。     

用压力传感器产气技术评定玉米秸秆添补苜蓿的组合效应

采用压力传感器体外产气技术,研究了玉米秸秆添补不同比例0(AH0)、20%(AH20)、40%(AH40)、60%(AH60)、80%(AH80)与100%(AH100)苜蓿(AH)在产气量上的组合效应。各组的组合效应均在24h达到最大值,24h后则随培养时间的延长而下降,但只有AH40组,亦即当苜蓿添加比例占"玉米秸秆-苜蓿"组合的40%时达到显著水准(P<0.05),且以AH40组下降较慢,在48h仍达到显著水准(P<0.05)。就单一的产气指标而言,玉米秸秆添补苜蓿的比例以占整个日粮总量的40%为宜。