草坪草屑的加工与利用

我国每年修剪草坪产生大量的草坪草屑,对草坪草屑的加工利用,可以对我国能源、饲料、肥料及蛋白资源的短缺起到一定的缓解作用,因此如何对草坪草屑进行合理利用已成为一项重要的研究课题。本文综述了草坪草屑能源化、饲料化、肥料化和深加工4种利用方式,详细介绍了草坪草屑在发酵生产能源、饲喂家畜、堆肥还坪以及加工叶蛋白等方面的研究进展,指出禾本科草坪草屑和豆科草坪草屑应采用不同的处理方式,对各加工方式的投入和产出也应进行进一步的量化核算,同时总结并展望了草坪草屑利用方式的发展前景。     

High dietary energy level stimulates growth hormone receptor and feed utilization in large Atlantic salmon (Salmo salar L.) under hypoxic conditions

This study examines how appetite and growth regulation of Atlantic salmon are affected by low dissolved oxygen (LO) and dietary digestible energy levels (DE: high [HE] vs. low [LE]). Long‐term exposure to LO resulted in a reduced feed intake, growth, digestible protein and fat retention efficiencies and increased feed conversation ratio and plasma ghrelin concentrations (p < .05) compared to high dissolved oxygen (HO). Pair‐feeding of rations based on the feed intake of the LO groups, but fed at HO, resulted in a 50% growth improvement in HE diet groups. This suggests that the poor growth under LO was not entirely caused by the reduced feed intake. Salmon adapted to LO by increased haemoglobin concentrations, while osmoregulation was affected by increased plasma chloride concentrations (p < .05). Plasma ghrelin concentration was unaffected by DE (p > .05). Growth regulation was affected by the HE diet, with increased liver and muscle growth hormone receptor ghr1 mRNA (p < .05), regardless of oxygen level. The growth depression due to low oxygen appears to be related to higher metabolic costs, while higher DE upregulates the GH‐IGF system at the ghr1 level and found to be beneficial for growth, feed intake, oxyregulation and osmoregulation under hypoxia.     

Effects of Panax ginseng extract in practical diets for rainbow trout (Oncorhynchus mykiss) on growth performance,immune response and resistance to Yersinia ruckeri

In a preliminary in vitro study, a Panax ginseng extract exhibited an evident antibacterial activity against Yersinia ruckeri and Lactococcus garvieae and affected the respiratory burst and proliferation of rainbow trout Oncorhynchus mykiss leukocytes. Subsequently, the effects of a dietary ginseng extract supplementation on growth, blood biochemical profile, innate immune response and resistance against Y. ruckeri infection were investigated in vivo in rainbow trout juveniles. Four experimental diets were obtained by adding 0.0%, 0.01%, 0.02%, 0.03% of ginseng ethanolic extract to a commercial feed. Each diet was fed to triplicate groups of fish (mean body weight 30.5 ± 0.15 g) at 1% of body weight day^?1 for 10 weeks. The dietary supplementation with ginseng extract did not affect growth performance, feed utilization, biometric traits and fish whole body composition (P > 0.05). No major changes due to graded levels of ginseng extract in the diet were observed in blood biochemical parameters except for increasing plasma triglycerides and non‐esterified fatty acids in fish fed diets including 0.01% and 0.02% of extract (P < 0.05). The innate immune response was barely modulated by the dietary addition of ginseng extract. Serum lysozyme and leukocytes respiratory burst activities were just slightly increased in fish fed all the ginseng extract‐supplemented diets compared with controls, whereas serum antiproteases and leukocyte MPO were not affected (P > 0.05). The dietary administration of ginseng extract induced a reduction in mortality of rainbow trout infected with Y. ruckeri, although no significant differences between treated and control groups were observed (P > 0.05).     

Effect of dietary phosphorus levels on growth and body composition of crucian carp,Carassius auratus under indoor and outdoor experiments

Indoor and outdoor experiments were carried out simultaneously to evaluate the effects of dietary phosphorus levels on growth performance and body composition of crucian carp. Monocalcium was used to formulate extruded feed containing available phosphorus (AP) of 1.5 (D1), 4.7 (D2), 6.3 (D3) and 9.0 (D4) g kg^?1. Twelve 500‐L recirculating tanks were assigned to four triplicate groups with each tank stocked with 15 juveniles (39.88 ± 0.14 g) for indoor experiment. Twelve polyethylene enclosures were assigned to four groups with each one stocked with 120 juveniles (44.08 ± 1.36 g). After 8 weeks of feeding, survival ranged from 96% to 100%. Weight gain, special growth rate, protein efficiency ratio and feed conversion rate did not show significant differences among dietary treatments in both experiments. Fish cultured in the enclosures grew better, although D1 and D2 treatments did not reach significant level. Crude protein and phosphorus content of the fish were not significantly affected by dietary phosphorus level. Moisture, crude lipid, crude ash and vertebrae phosphorus were significantly affected by different phosphorus levels. Based on vertebrae phosphorus, crucian carp cultured in the tanks and in the enclosures showed phosphorus deficiency under 4.7 g kg^?1 and 6.3 g kg^?1 AP, respectively.     

Effects of dietary protein and lipid levels with different protein‐to‐energy ratios on growth performance,feed utilization and body composition of juvenile red‐spotted grouper,Epinephelus akaara

An 8‐week feeding trial was conducted to assess dietary protein and lipid levels on growth performance, feed utilization and body composition of juvenile red‐spotted grouper (7.85 ± 0.03 g fish^?1). Nine semi‐purified diets were formulated containing varying protein levels (440–520 g kg^?1, dry matter) and lipid levels (60–120 g kg^?1, dry matter). The weight gain of juvenile Epinephelus akaara was affected by dietary protein (p = .005) and its interaction with dietary lipid (p = .020). Viscerosomatic index, intraperitoneal fat ratio and whole‐body lipid level increased with increasing dietary lipid level (p < .001). Nitrogen retention was not affected by dietary protein and lipid, while lipid retention decreased with increasing dietary lipid level (p < .001). The plasma blood urea nitrogen increased with increasing dietary protein level (p = .003). This study showed that diet with 520 g kg^?1 protein and 60 g kg^?1 lipid with 30.58 mg kJ^?1 P:E provided a maximal growth for this species. Moreover, an increase in dietary lipid levels (from 60 to 90 g kg^?1) could reduce the protein requirement (from 520 to 480 g kg^?1) without affecting the growth performance, while higher fat deposition was observed in fish fed high‐lipid diets.     

饲料脂肪水平对俄罗斯鲟幼鱼生长、血液生化指标及抗氧化性能的影响

以鱼油、豆油、亚麻籽油等比例混合,配成脂肪含量分别为5.45%(L1)、7.00%(L2)、10.44%(L3)、14.37%(L4)、16.34%(L5)、18.91%(L6)及20.15%(L7)的等氮饲料,饲喂俄罗斯鲟(Acipenser gueldenstaedtii)幼鱼[(6.20±0.02)g]8周。实验结果表明,L3组的终末体质量、增重率最大,但与L2组间无显著差异(P0.05),L3组的蛋白质效率显著高于其它组(P0.05),且饲料系数最低。L6和L7组终末体质量、增重率和蛋白质效率显著低于L2和L3组(P0.05)。将幼鱼的增重率与饲料脂肪水平进行回归分析,得出俄罗斯鲟幼鱼在饲料脂肪水平为10.69%时生长最佳。随着饲料脂肪水平的升高,各组鱼的肝体比和体粗脂肪有上升趋势,其中肝体比在饲料脂肪含量大于14.37%时显著增大(P0.05)。血清中的甘油三酯、胆固醇含量也随脂肪水平升高而显著提高(P0.05),提示脂肪过高会影响俄罗斯鲟幼鱼的生长,降低蛋白质效率,导致脂肪在体内的过量积蓄。L7组鱼血清中高密度脂蛋白胆固醇含量最高,而L1组鱼的低密度脂蛋白胆固醇含量最高。肝脏脂蛋白酯酶活性随饲料脂肪水平的提高而升高,脂肪酸合成酶活性则随脂肪水平升高而降低,提示饲料脂肪水平的提高会促进鱼体脂肪的分解代谢。肝脏丙二醛含量和超氧化物歧化酶活性均随着饲料脂肪水平的提高显著升高(P0.05),表明脂肪含量过高会导致脂质过氧化,引发机体抗氧化酶活性的升高。综合俄罗斯鲟幼鱼的生长、血液指标及抗氧化性能,建议生产中将幼鱼的饲料脂肪水平控制在7.00%~10.69%。     

Finding suitable growth models for turbot (Scophthalmus maximus L.) in aquaculture 1 (length application)

Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped.     

3种植物生长调节剂对坛紫菜自由丝状体生长与光合色素含量的影响

采用单因素分析法,比较研究了添加3种外源植物生长调节剂(吲哚乙酸IAA、2,4-二氯苯氧乙酸2,4-D、激动素KT)对野生型坛紫菜(Pyropia haitanensis)自由丝状体生长及光合色素含量的影响。结果表明:与对照组相比,低浓度的IAA(0.5~4.0 mg·L~(-1))和KT(0.5~2.0 mg·L~(-1))对藻体的特定生长率有显著影响,以2.0 mg·L~(-1)IAA和1.0 mg·L~(-1)KT对藻体的促生长效应最大,培养25 d时藻体鲜重增加最大,分别是对照组的1.90倍和1.52倍(P0.05)。高浓度的IAA(6.0~10.0 mg·L~(-1))和KT(4.0~10.0 mg·L~(-1))却会抑制藻体生长(P0.05)。培养25 d时,与对照组相比,2.0 mg·L~(-1)IAA和1.0 mg·L~(-1)KT均有利于叶绿素a(Chl a)和类胡萝卜素(Car)的合成,Chl a含量分别增加了23.7%和23.8%;Car含量分别增加了31.0%和28.6%(P0.05)。然而,高浓度的IAA和KT(6.0、10.0 mg·L~(-1))不利于Chl a的合成,其处理浓度越高,Chl a含量下降越多。与对照组相比,较低浓度的IAA(1.0~2.0 mg·L~(-1))明显促进藻红蛋白(PE)和藻蓝蛋白(PC)合成,其中2.0 mg·L~(-1)IAA处理组PE、PC含量最高,分别增加了59.1%和45.7%(P0.05)。较低浓度的KT(0.5~2.0 mg·L~(-1))均有利于PE、PC合成,其中0.5 mg·L~(-1)KT处理组的PE、PC含量增加最多,分别提高了48.4%和50.5%(P0.05)。高浓度的IAA(6.0、10.0 mg·L~(-1))和KT(10.0 mg·L~(-1))则明显降低了PE、PC合成(P0.05)。2,4-D对藻体的特定生长率和光合色素合成无显著影响(P0.05)。     

宁南霉素等药剂对番茄黄化曲叶病毒病的田间防效

[目的]评价宁南霉素、艾德拉和碧护3种药剂混合使用防治番茄黄花曲叶病毒病的效果。[方法]通过田间试验研究8%宁南霉素、艾德拉绿(花、果)与碧护组成的药剂对番茄黄化曲叶病毒病的防治效果。[结果]8%宁南霉素、艾德拉绿(花、果)与碧护组成的试验药剂对番茄黄化曲叶病毒病具有很好的田间防治效果,第3次施药后10、20、30 d防效均在82%以上,与对照药剂番茄黄化曲叶病毒灵差异达极显著水平,且其产量比清水对照增加25 747.5 kg/hm~2,保产率为103.90%。[结论]宁南霉素、艾德拉和碧护混合使用对番茄黄花曲叶病毒病具有较好的防治效果,为番茄黄花曲叶病毒病的有效防治提供了理论依据。     

烟酰胺腺嘌呤二核苷酸(NAD)合成途径和水稻叶片早衰

叶片是植物进行光合作用的主要场所,其衰老由内源遗传发育信号和外界环境胁迫所启动,是一个非常复杂有序的调控过程。烟酰胺腺嘌呤二核苷酸(nicotinamide adenine dinucleotide,NAD)是脱氢酶的辅酶,在糖酵解、糖异生、三羧酸循环以及呼吸链等代谢中发挥着不可替代的作用。最新研究表明,水稻NAD生物合成参与调控沉默信息调控因子Sirtuins的生物活性、组蛋白H3K9去乙酰化、植物激素茉莉酸(JA)和叶片衰老。本文综述了有关水稻叶片衰老的细胞生理特征、Sirtuins酶活、NAD生物合成以及水稻早衰的OsSRT1-NAD调控途径和OsSRT1-Me OH-JA调控途径,以期阐明水稻叶片衰老的分子机理及其调控途径,为高产育种提供相应的理论参考。