Effects of dietary sodium butyrate on growth,digestive enzymes,body composition and nutrient retention-related gene expression of juvenile yellow catfish (Pelteobagrus fulvidraco)

An 8-week feeding trial was conducted to evaluate the effects of sodium butyrate (SB) on growth, digestive enzymes, body composition and nutrient retention-related gene expression of juvenile yellow catfish (Pelteobagrus fulvidraco). Five isonitrogenous and isolipidic diets (420 g/kg protein and 90 g/kg lipid) were formulated to contain 0 (control), 250, 500, 1,000 or 2,000 mg/kg SB. Triplicate groups of 40 fish (BW = 1.26 ± 0.01 g) per tank (300-L cylindrical fiberglass tanks) for each diet were fed to apparent satiation twice daily. Stomach, hepatopancreas and intestine samples were obtained for digestive enzymes activities analyses. A real-time quantitative PCR analysis was performed to determine the relative expression of target of rapamycin (TOR) and lipoprotein lipase (LPL) in the hepatopancreas and intestine. Fish fed the diets supplemented with SB at 500 and 1,000 mg/kg showed significantly higher specific growth rate and significantly lower feed conversion ratio compared to the control (P < 0.05). Dietary SB inclusion did not alter activities of intestinal amylase, creatine kinase and sodium–potassium adenosine triphosphatase (Na⁺/K⁺-ATPase), but increased activities of hepatic trypsin, stomachic lipase, intestinal lipase, alkaline phosphatase and γ-glutamyl transpeptidase for fish fed 1,000 mg/kg SB compared to the control (P < 0.05). Intestine length index, intestine somatic index, fold height and muscular thickness of distal intestine were significantly higher in 1,000 mg/kg SB groups compared to the control (P < 0.05). Significantly higher levels of whole-body crude protein, ash, calcium, phosphorus, nutrition retention and relative mRNA of intestinal TOR were observed in 1,000 mg/kg SB group (P < 0.05). Whole-body lipid content and hepatopancreas LPL mRNA expression in 2,000 mg/kg SB group were significantly higher than the control (P < 0.05). Relative mRNA levels of intestinal LPL and hepatopancreas TOR were significantly higher in the 500 mg/kg SB group compared to those in other groups (P < 0.05). The increased growth performance, digestive enzymes and nutrient retention in fish fed the diets supplemented with SB at 500 and 1,000 mg/kg suggests that SB can be a desirable growth promoter as an antibiotic alternative in diets.     

表面活性剂强化过硫酸钠氧化修复石油烃污染土壤

为了提升石油烃污染土壤的修复效率，考察了不同表面活性剂(吐温-80 (Tw-80)、曲拉通X 100 (TX 100)、十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS))对过硫酸钠氧化土壤中石油烃的强化效果，并分析了表面活性剂SDS强化修复效果较优的原因。土壤中石油烃的去除率遵循如下趋势：SDS>SDBS>TX 100>Tw-80。SDS强化修复效果较优可能与其在土壤中吸附量较小对石油烃的增溶效果好、上清液中过渡态金属含量较高及对过硫酸钠分解消耗少有关。通过优化反应参数，可以进一步提高SDS强化过硫酸钠氧化修复石油烃污染土壤的效率，对采自武汉和盘锦的两种石油烃污染土壤都具有较好的修复效果。     

厨余生化机产物的种子发芽指数及影响因素研究

【目的】确定厨余生化机产物腐熟度及Na⁺、小分子有机酸与种子发芽指数(Seed germination index,GI)的关系，促进厨余生化机产物的资源化利用及推广，同时，开拓固碳于土壤达到碳中和目标的新技术途径。【方法】利用萝卜Raphanus sativus种子测定厨余生化机产物的GI，并模拟不同浓度Na⁺、小分子有机酸溶液，分析其对GI的影响。【结果】厨余生化机产物的GI为1.53%，不满足堆肥基本腐熟的标准(GI≥50%)，厨余生化机产物浸提液稀释10倍时，溶液中Na⁺质量浓度为75.25 mg/L,GI为43.73%。模拟试验结果显示，随着Na⁺浓度的升高，GI呈下降趋势，当Na⁺质量浓度为1 200 mg/L时，GI为52.86%。随着小分子有机酸浓度的增加，GI呈下降趋势，当乙酸和乳酸质量浓度高于100 mg/L、丙酸和丁酸质量浓度高于50 mg/L时，GI小于50%。丙酸、丁酸对GI的影响强于乙酸、乳酸。【结论】厨余生化机产物的GI未达到堆肥基本腐熟的标准，制...     

Tolerance and safety evaluation of sodium sulfate:A subchronic study in laying hens

Sodium sulfate (Na₂SO₄) is a readily available chlorine-free source of sodium, which could be used to reduce sodium chloride to maintain the ratio between chlorine and sodium in poultry diets. Dietary supplementation with excessive levels of Na₂SO₄ might be detrimental to bird''s health and performance. A subchronic study was carried out to investigate the potential adverse effects of an accidental oversupply of Na₂SO₄ in the diets of laying hens. Four hundred and fifty 21-week-old Hy-Line White layers were randomly assigned to 5 treatments with 6 replicates. The birds were fed diets supplemented with 0 (control), 0.3%, 0.6%, 1.5%, and 3.0% Na₂SO₄ for 8 weeks. Laying performance, egg quality parameters, clinical blood parameters, histopathology, intestinal barrier functions, and intestinal microflora composition were measured. No clinical signs of intoxication or mortality were observed during the experimental period. The results of this study showed that the optimal levels of Na₂SO₄ (0.3% to 0.6%) significantly improved the laying rates, average daily egg mass, and eggshell quality of hens compared to the control (P < 0.05). However, 3.0% Na₂SO₄ produced negative effects on laying performance, eggshell quality, blood biochemistry, and particularly on liver and kidney pathology, and intestinal morphology and barrier functions compared with the controls. Although minor changes were observed in clinical blood parameters of hens receiving 1.5% Na₂SO₄, these were not considered to be of toxicological significance due to the absence of any organ pathological changes in hens. In conclusion, our results indicated that a Na₂SO₄ concentration of 1.5% was non-deleterious to laying hens after a daily administration for 56 d, namely that dietary supplementation of up to 5 times the maximum recommended dose is safely tolerated by laying hens.     

叠氮化钠诱变燕麦M1代的主要性状分析

为明确叠氮化钠(NaN₃)处理后燕麦(Avena sativa) M1代植株主要性状的变化，本研究以两个燕麦品种‘爱沃’(‘Everleaf’)和‘青永久709’(‘Qingyongjiu 709’)种子为材料，设置不同叠氮化钠浓度(0，5，10，15，20mM)和不同处理时间(1，2，3h)，将处理后的种子播到田间，观察M1代植株的农艺性状，并对主要性状进行测定分析。结果表明，NaN₃处理后燕麦M1代的生育期较对照推迟2~5d，株高和主穗粒数明显下降且‘青永久709’的降幅更大，在15mM/3h处理下，与对照相比，其株高和主穗粒数分别下降了24.06%和76.69%。另外，两品种燕麦M1代旗叶长也低于对照，但旗叶宽却高于对照，从而对旗叶面积造成影响。其中‘青永久709’的M1代旗叶面积总体大于对照，但‘爱沃’平均减小了7.23%。NaN₃处理后燕麦M1代各指标均发生了不同程度的变化，其中有效分蘖数和主穗粒重的变化最大。‘爱沃’和‘青永久709’的M1代主穗粒重最大变异系数分别为87.92%和90.80%。主成分分析表明，两品种被清晰地划分为两个彼此独立的类群，不同品种的诱变群体也分属不同的亚群，且‘青永久709’的M1代各指标的变化幅度总体大于‘爱沃’。     

不同形态硒及用量对幼苗期谷子生长与生理的影响

为探究不同形态硒及用量对谷子生长和抗性的影响，选用0.0、0.1、0.5、1.0、10.0mmol/L亚硒酸钠和纳米硒，通过水培试验研究不同形态硒浓度对谷子株高、茎粗、根系、硒含量和酶活性的影响。结果表明，2种形态硒随着浓度的升高，株高均呈先升高后降低的趋势；亚硒酸钠对茎粗的影响呈开口向下的抛物线趋势，纳米硒对茎粗有显著的抑制作用。亚硒酸钠对根长和根冠比的影响呈先增加后降低的趋势；低浓度纳米硒对根长影响不显著，高浓度纳米硒对根长有显著的抑制作用；纳米硒对谷子根冠比抑制作用明显。2种形态硒均可提高谷子的硒含量；2种形态硒及其不同浓度对超氧化物歧化酶、过氧化氢酶活性及蛋白质含量均有显著影响，对过氧化物酶活性影响不显著。结合Circos-弦图、谷子株高、茎粗、根系、硒含量和酶活性等试验结果，得出喷施0.1mmol/L的纳米硒溶液对谷子生长、硒含量及酶活性提高效果显著，适宜在谷子种植中应用。