饲料蛋白含量对稻-黄颡鱼共作模式气态氮排放、黄颡鱼生长和氮利用率的影响

【目的】明确饲料蛋白含量对稻-黄颡鱼共作模式下N₂O和NH₃挥发特征及黄颡鱼生长的影响,有利于稻-黄颡鱼综合种养的高效、绿色发展。【方法】采用盆栽模拟试验,以常规单养黄颡鱼模式为对照,系统研究了不同饲料蛋白含量对稻-黄颡鱼共作模式下N₂O和NH₃的排放特征、水体和底泥的氮含量以及黄颡鱼生长的影响。【结果】在相同蛋白含量下,稻-黄颡鱼共作模式的N₂O和NH₃挥发分别比单养黄颡鱼模式降低18.3%和76.20%,水体总氮和无机氮含量降低41.30%和48.85%,黄颡鱼蛋白累积量增加20.00%,氮利用率增加171.50%。在稻-黄颡鱼共作模式下,提高饲料蛋白含量会显著增加N₂O排放量和水体残留氮含量,但对NH₃挥发无显著影响;黄颡鱼特定生长率和蛋白累积量与饲料蛋白含量呈二次曲线关系。饲料氮利用效率随饲料蛋白含量增加呈线性降低趋势。【结论】综合考虑黄颡鱼生长和N₂O排放以及养殖水体氮残留等因素,确定稻-黄颡鱼共作模式饲料蛋白含量不宜超过43.04%。     

基于芒果果肉颜色的品质检测技术

以芒果品种‘贵妃’为试材,利用光谱仪测定L、a、b值,同时测定果实的硬度及糖酸度,采用偏最小二乘法(PLS)建立基于颜色值的可溶性固形物(SSC)、硬度及可滴定酸(TA)的品质预测模型。预测模型的建模相关系数R可溶性固形物含量、硬度及可滴定酸含量分别为0.962 2、0.946 4和0.959 2;均方误差分别为0.658 1%、0.992 7 kg/cm~2及0.827 5 g/L。预测集拟合方程的相关系数分别为0.965 6、0.949 0和0.925 7;均方误差分别为0.626 7%、1.159 0 kg/cm~2和0.999 2 g/L。结果表明:芒果预测模型的预测准确度,可溶性固形物高于硬度和可滴定酸,基于‘贵妃’芒果采后品质的果肉颜色值快速检测可行。     

茉莉酸甲酯重复刺激对白木香所结沉香中沉香四醇含量的研究

利用茉莉酸甲酯，重复刺激诱导白木香结香，提高所结沉香中沉香四醇的含量。白木香经锯伤、及 3 种浓度（0、10、50 g/L）茉莉酸甲酯重复刺激（仅 1 次、1 次/月、2 次/月、4 次/月）诱导结香，时长 6 个月，HPLC法测定所结沉香中沉香四醇的含量。结果表明：10 g/L 茉莉酸甲酯 2 次/月刺激诱导白木香所结沉香中沉香四醇含量最高，为 1.78 mg/g。由此可知，利用植物激素茉莉酸甲酯诱导、重复刺激均能明显提高白木香所结沉香中沉香四醇的含量。     

苗期喷施茉莉酸甲酯对香稻品种象牙香占香气的影响

茉莉酸甲酯能够提高植物的抗逆境胁迫能力,但在对香稻香气物质2-乙酰基-1-吡咯啉（2-AP）的影响研究还鲜有报道。以香稻品种象牙香占为试验材料,设置茉莉酸甲酯3种喷施浓度（0.25、0.50和1.00 mmol/L）,研究苗期喷施对香稻幼苗2-AP合成与累积、香气前体物质含量、香气相关酶活性、香气相关基因表达量调控、抗性酶活性变化和秧苗素质的影响。结果表明,与对照（CK）相比,喷施适当的茉莉酸甲酯浓度（0.50～1.00 mmol/L）,香稻幼苗2-AP含量增加,香气合成前体物质1-吡咯啉、丙酮醛和1-吡咯啉-5-羧酸（P5C）含量提高,二胺氧化酶2基因（DAO4）、鸟氨酸转氨酶基因（OAT）和脯氨酸脱氢酶基因（ProDH）表达量提升。茉莉酸甲酯处理还提高了香稻秧苗素质,增加了抗性酶活性,提高了抗氧化能力。适度的茉莉酸甲酯能提高香稻2-AP含量和秧苗素质,归因于相关酶活性和基因表达量的提高。     

云南2种野生苜蓿资源对酸铝胁迫的响应分析

以云南2种野生苜蓿资源为材料,采用水培法研究酸铝胁迫对幼苗生长的影响。通过分析酸、铝单一及复合处理下幼苗根长、株高、生物量、根系活力、叶绿素和丙二醛含量、过氧化物酶和超氧化物岐化酶活性变化,比较2种苜蓿对酸、铝的耐性。结果显示：随着酸度的增加,天蓝苜蓿和紫花苜蓿幼苗的生长均受抑制,pH 7.0和pH 3.0处理对比分析,天蓝苜蓿在根长、株高、生物量、根系活力增幅比紫花苜蓿的增幅小;铝胁迫后,2种苜蓿在根长、株高、生物量、根系活力指标上均具有显著差异,且随着铝浓度的增大,受抑制越严重;酸、铝共同胁迫对2种苜蓿幼苗生长的影响大于单一胁迫对它的影响,pH 4.5,Al ³⁺浓度300 mg/L时,2种苜蓿生长受抑最严重。酸、铝单一胁迫及复合处理均显著影响2种苜蓿,但天蓝苜蓿对酸、铝及酸铝的耐性优于紫花苜蓿。     

酸刺激和谷氨酸处理对不同粳稻品种稻谷γ-氨基丁酸积累的影响

以常优94 1、浙湖9423、R717、中超123、赚钱1号和日本晴6个粳稻品种为材料,比较研究了种子萌发时间、酸刺激和L 谷氨酸（L-Glu）浸泡处理对不同品种稻谷中GABA积累的影响。萌发活化4～6 d、pH 6.0缓冲液浸泡2 h及50 mmol/L的L Glu 浸泡12 h能显著促进萌发稻谷中GABA的积累,使萌发稻谷中GABA含量较萌发前增加0.8～5.9倍; 不同品种稻谷GABA初始含量不同,萌发活化、酸刺激和L-Glu浸泡处理对稻谷积累GABA的促进效应具有很大的品种差异。经处理后中超123和日本晴两个品种GABA含量高,分别达到1.1236 mg/g和0.9064 mg/g,是萌发前的5.6和22倍。     

不同品质类型花生籽仁脂肪酸积累规律研究

以高蛋白品系KB008、高脂肪品种花17和高油酸/亚油酸品种农大818为材料对花生籽仁发育过程中脂肪酸积累规律进行研究。结果显示,在花生籽仁发育过程中,籽仁中脂肪的积累速度呈先快后慢的趋势。油酸亚油酸比值(O/L)受遗传因素影响较大,收获期O/L值以农大818最高,KB008最低,差异显著。不同品种成熟期的脂肪酸组分相对含量存在差异,高蛋白品种成熟期亚油酸、棕榈酸、硬脂酸、花生酸和山嵛酸相对含量显著高于高脂肪和高O/L值品种,而其油酸和二十四烷酸相对含量明显低于后两者。高脂肪品种和高O/L值品种成熟期脂肪酸组分相对含量差异不明显。     

侗乡油茶及其茶文化初探

侗族是我国西南地区一个古老的少数民族，总人口约296．6万，主要分布在湘、黔、桂三省毗邻区域。侗族是一个勤劳智慧的民族，他们勤劳耕作，“饭稻鱼羹”，繁衍发展，创造了极丰富的民族特色文化体系。尤其是侗族的饮食文化，特色明显，品种丰富，如酸鱼、酸肉、牛羊瘪、油茶等，其中油茶在侗族饮食文化中占有重要地位。油茶，颐名思义，与水泡的茶不一样，而是与油有关的茶饮：同时，喝油茶除了品饮之外，主要还是用来食用充饥的，     

淋洗剂对土壤铅的提取效果研究

淋洗技术是修复污染土壤的一种方法,特别是污染土壤生物修复技术的一种补充。以龙岩某钢铁厂附近重金属铅严重污染的土壤样品为研究对象,用HCl、柠檬酸和Na2-EDTA三种萃取剂的不同浓度对土壤铅污染进行连续浸提,并比较三种不同淋洗剂对土壤铅的提取效果,讨论研究最佳淋洗的工艺条件。结果表明:HCl、0.16柠檬酸和Na2-EDTA三种萃取剂各浓度第一次对土壤铅的最大提取率分别为25.88%(0.16mol/L)、23.41%(0.16mol/L)、76.32%(0.14mol/L,),Na2-EDTA更适合作为土壤铅的萃取剂,最佳的萃取浓度为0.14mol/L,连续浸提2次即可。     

甘蓝型油菜AOC基因家族鉴定与表达分析

丙二烯氧化物环化酶(allene oxide cyelase,AOC)是茉莉酸(jasmonic acid,JA)信号途径中一个重要的合成酶,在植物生长发育、光合作用、物质代谢和逆境胁迫应答等多个方面发挥重要作用.为了探究AOC基因在甘蓝型油菜(Brassica napus L.)中的家族特征,本研究以4个拟南芥AtA...     

Use of freshly cultured lactic acid bacteria as silage inoculants

The use of freshly cultured lactic acid bacteria in comparison with conventional freeze-dried preparations as inoculants for grass silage was examined. Perennial ryegrass was ensiled in laboratory silos, either untreated or treated with formic acid, or a commercial freeze-dried strain of Lactobacillus plantarum , or a fresh culture of the same strain of L. plantarum , or fresh cultures of Pediococcus pentosaceous , or Lactococcus lactis alone or in combination with L. plantarum. All inoculants were applied at a rate of 10⁶ colony-forming units g⁻¹ fresh matter, with the mixtures containing a 1:l ratio of each species. Herbage treated with freshly cultured inoculants exhibited shorter lag times, in relation to the initiation of pH decline, than those associated with untreated or freeze-dried inoculant-treated herbages. Treatment of herbage with inoculants containing L. plantarum increased the initial speed of pH decline. In comparison with silages made with freeze-dried L. plantarum , in measurements made during the initial 14 d of ensilage, those inoculated with fresh cultures bad significantly (P<0·05) higher lactic acid concentrations and significantly (P·0.05) lower pH values. Both P. pentosaceous and L. lactis initiated a rapid fermentation, but compared to L. plantarum alone, or mixtures of L. plantarum with P. pentosaceous or L. lactis , these cultures demonstrated intermediate rates of lactic acid production and pH decline. All mature (105 d) silages were of good quality with pH values of four or less, low ammonia-N concentrations (<100gkg⁻¹ total N) and no detectable levels of clostridia or butyric acid. Results suggested that the main advantage of freshly cultured inoculants over their freeze-dried counterparts may lie in their metabolic state when added to herbage.     

Effects of initial air removal methods on microorganisms and characteristics of fermented plant beverages

The effects of 3 different methods for removing the initial air on the properties of fermented plant beverages produced from phom-nang seaweed (Gracilaria fisheri) and wild forest noni (Morinda coreia Ham.) were investigated. Only method M which covered the space above the fermentation liquid with a water filled plastic bag produced no surface film of yeast, had the highest acidity and also antibacterial activity from both plants after 90 days of fermentation. However, the yeast count still exceeded the standard guidelines for plant beverages. The fermented beverage from wild forest noni showed more antibacterial activity against 3 of 4 pathogenic bacteria tested than that from the phomnang seaweed, probably for its higher levels of acidity and ethanol content. Lactic Acid Bacteria (LAB) isolated from the fermentation samples from days 1-5 using the method M from both fermented plant beverages were Leuconostoc mesenteroides supsp. mesenteroides and Leu. mesenteroides subsp. dextranicum while presence of Lactobacilus plantarum was only recorded at days 4-5 in the wild forest noni beverage. From days 6-14 the isolates were Lactobacillus plantarum, Lactobacillus fermentum and Lactobacillus brevis from wild forest noni beverage, whereas only L. brevis was not detected in the seaweed beverage. During days 21-45 both beverages had a similar LAB population of L. plantarum and L. brevis while L. coryniformis was only found in the wild forest noni beverage. Between days 60-90 in both plant beverages only L. plantarum and Lactobacillius sp. were detected.     

Fermentation characteristics and aerobic stability of grass silage inoculated with Lactobacillus buchneri, with or without homofermentative lactic acid bacteria

Aerobic spoilage by yeasts and moulds is a major cause of reduced nutritional value of silage and increases the risk of potential pathogenic microorganisms. Recent studies have shown that inoculation with Lactobacillus buchneri inhibits yeast growth and reduces the susceptibility to aerobic spoilage of various ensiled forages. The aim of this study was to determine whether these effects are retained when L. buchneri is added in combination with homofermentative lactic acid bacteria. In three experiments, silages were produced from perennial ryegrass [240–421 g kg⁻¹ dry matter (DM)] inoculated with L. buchneri or L. buchneri plus a mixture of Pediococcus pentosaceus and Lactobacillus plantarum (inoculant PL). Uninoculated silage and silage inoculated with PL alone served as controls. Silages were examined for pH and DM loss in the course of ensilage and chemical and microbiological composition and aerobic stability after 3–4 months. L. buchneri plus PL and PL alone increased the initial rate of pH decline. L. buchneri alone and L. buchneri plus PL enhanced aerobic stability and, in general, reduced yeast and mould counts. In addition, these inoculants increased the final pH and DM loss and the concentrations of acetic acid and 1,2-propanediol (or propionic acid and 1-propanol instead of 1,2-propanediol), and decreased the concentration of lactic acid. The effects of L. buchneri on fermentation products increased with decreasing DM content. In silages of less than 270 g kg⁻¹ DM, L. buchneri increased the ammonia-N concentration. It is suggested that this was associated with the relatively high final pH resulting from the high metabolic activity of L. buchneri in these silages.     

The effects of lactic acid bacteria on the fermentation,aerobic stability and nutritive value of maize silage

Maize was harvested at one‐third milk line (297 g kg^?1 DM) stage. All inoculants were applied at 1 × 10⁶ cfu g^?1 of fresh forage. After treatment, the chopped forages were ensiled in 1·5‐L anaerobic jars. Three jars per treatment were sampled on days 2, 4, 7, 12 and 90 after ensiling, for chemical and microbiological analysis. Homofermentative LAB‐inoculated silages had lower pH and higher lactate:acetate ratio (except for Lactobacillus plantarum/Pediococcus cerevisiae and L. plantarum/Propionibacterium acidipropionici) than the control and both heterofermentative LAB‐inoculated silages. Both L. buchneri inhibited yeast growth and CO₂ production during exposure of silage to air. The L. plantarum/P. cerevisiae, L. plantarum (Ecosyl) and L. plantarum/Enterococcus faecium‐inoculated silages had higher dry‐matter digestibility than the control and L. buchneri‐inoculated silages. Inoculants did not affect digestibility of neutral detergent fibre, except for L. buchneri (Biotal), organic matter nor ME content of silages. The LAB silage inoculants generally had a positive effect on maize silage characteristics in terms of lower pH and shifting fermentation toward lactate with homofermentative LAB or toward acetate with L. buchneri. The use of L. buchneri can improve the aerobic stability of maize silages by the inhibition of yeast activity.     

Obtaining of a symbiotic product based on lactic bacteria, pollen and honey

This study presents the evolution of a Lactobacillus plantarum 2s strain and of a Lactobacillus acidophilus 1a strain on media containing pollen and honey. The following parameters were determined: CFU value, lactic acid production, sugar consumption and presentation of the final product. The researches were performed during 72 h, in tightly closed recipients, at a temperature of 37 degrees C, containing various quantities of milled or non-milled pollen (P1: 20 g non-milled pollen, 3 g honey, 5 mL distilled water; P2: 20 g milled pollen, 3 g honey, 5 mL distilled water; P3: 20% non-milled pollen, 3% honey; P4: 20% milled pollen, 3% honey). The media were very well homogenized before inoculation. The inoculation was made only after the medium gained a homogenous consistency. The inoculum consists of a 48 h culture of Lactobacillus plantarum 2s and Lactobacillus acidophilus, on LE medium, in equal proportions. The testing of the nutritive value of the symbiotic product was made on wistar rats, males and females, divided into lots of 10 animals each. The animals were administered symbiotic product every day, in their food, in intakes of 2 mg kg(-1) (lot I), 20 mg kg(-1) (lot II) and 200 mg kg(-1) (lot III), compared to a control. During the 4 weeks of the experiment, no lethality cases were recorded in any of lots, or in control. The animals involved in the experiment were examined daily and did not present changes of appetite, of behavior or clinical signs of disease.     

The effect upon fermentation and nutritive value of silages produced after treatment by three different inoculants of lactic acid bacteria applied alone or in combination

Silages were made from the first cut of a predominantly perennial ryegrass sward. The silages were either untreated (W) or treated with formic acid (31 t⁻¹, F) or with 10⁶ lactic acid bacteria (LAB) g⁻¹ grass of each of three strains alone (A. Lactobacillus plantarum MTD1; B, Pediococcus species 6A2; C, L. plantarum 6A6) or in combination (AB. AC) to give seven treatments. The silage fermentation in 10-kg silos was followed chemically and microbiologically and the nutritive value of selected treatments evaluated using 2-t silos.
The control silage (W) fermented well. Addition of formic acid restricted fermentation and produced a silage with a high ethanol concentration. After day 4, all inoculated silages had lower pH values and higher lactic acid concentrations and a higher ratio of lactic acid to acetic acid than the control silage. Chemically there was little difference between the inoculated silages in terms of final composition. Microbiologically the LAB applied in treatments B and C dominated the LAB populations in those silages when applied alone; however, they were suppressed when applied in combination with inoculant A.
When fed to sheep, the intake of the formic acid-treated silage was significantly ( P < 0·01) lower than that of the other silages and the intake of silage treated with inoculant A significantly ( P < 0·001) higher than that of silages treated with inoculants B and C. The apparent organic matter ( P < 0·001) and nitrogen ( P < 0·01) digestibilities of the formic acid-treated silage were also significantly lower than those of the other silages.     

An investigation into the effect of cultures of lactic acid bacteria on fermentation in silage

Twenty-one strains of lactic acid bacteria were subjected to a range of tests based on established criteria to ascertain their suitability for use as inoculants for silage. The tests included a monitor of their growth in the presence of representatives of the microflora of forage crops with which they might have to compete for substrate, and their ability to effect rapid acidification and achieve a low pH in conditions which simulate low and high ensiling potential. In addition, their ability to produce acid from sugars and their action against organic acids found in forage crops, together with their tolerance of acid, elevated temperatures and conditions of low moisture availability (e.g. in wilted material) and possible proteolytic and amylolytic activities were examined. None or these cultures satisfied all of these criteria. However, three strains ( Streptococcus durans str. 1024, Lactobacillus acidophilus , str. 2356 and Lactobacillus plantarum str. 6) had a greater potential than the others.     

Effect of microbial inoculants on the nutritive value of corn silage for beef cattle

This study investigated the effect of a new microbial inoculant product on the composition and nutritive value of corn silage in big silo over one year that used beef cattle. Six Holstein beef steer (BW = 225 +/- 17) were allotted to 2 x 2 repeated Latin square design at two 21 days periods (adaptation, 14 days and sample collection, 7 days) for evaluation the effect of microbial inoculation on the composition and nutritive value of corn silage for beef cattle. Two treatments, forages were untreated or treated at ensiling with Lactobacillus plantarum and Propionibacterium acidipropionici silage inoculants. After 45 days from ensiling, the ration that contained 94.5 and 5, 0.2, 0.2, 0.1% of DM silage and ground barely, mineral-vitamin, dicalcium phosphate, salt, respectively, were offered for free choice consumption. Treatment with Lactobacillus plantarum and Propionibacterium acidipropionici inoculant increased daily dry matter intake and subsequently NDF, ether extract, crude protein and ash. Apparent digestibility of DM and nutrients were significantly increased by microbial inoculation. Microbial inoculation can improve the nutritive value of corn silage for beef cattle.     

A note on ensiling safflower forage

Abstract The ensiling characteristics of safflower ( Carthamus tinctorius ) wilted to 290 and 411 g dry matter (DM) kg⁻¹ fresh material were studied in 1·5 l glass jars. The experiment included a control and the application of Lactobacillus plantarum at 3·3 × 10⁵ colony-forming units (cfu) per g of crop. After 60 days of ensiling, the pH of safflower silages was 4·6 and 4·0 in the control and inoculated silages respectively, with corresponding values for lactic acid, the major fermentation product, of 20 and 45 g kg⁻¹ DM. The silages from the anaerobic jars were stable upon aerobic exposure. It is concluded the safflower silage has potential as an alternative fodder in semiarid regions.     

The chemical composition and nutritive value of grass silages prepared with no additive or with the application of additives containing either Lactobacillus plantarum or formic acid

A mixture of perennial and hybrid ryegrasses(234 g DM kg^-1) was forage harvested and ensiled after a 24-h wilt in good ensiling conditions in 2-t capacity silos with no additive application (control) or with the application of either Lactobacillus plantarum , 4 × 10⁶ (g fresh weight of grass)^-1, or of 31 formic acid t^-1. Sufficient 2-kg capacity laboratory silos were also filled with grass to monitor the changes in chemical composition of the ensiled grass with time. In laboratory silos, inoculation with L. plantarum resulted in a more rapid fall in silage pH ( p < 0.001) and a more rapid production of lactic acid ( P < 0.001) than in the control silage. At the end of the storage period (laboratory silos, 80 d; 2-t silos, 200-300 d), the inoculated silos had lower pH ( p ammonia-N (g kg N¹) and acetic acid contents ( p < 0.01) and higher water soluble carbohydrate (WSC), lactic acid (P<00.1) and ethanol ( p < 0.05) contents than the control silage. The formic acid-treated silage had significantly lower contents of ammonia-N (g kg N^-1, p < 0.05), acetic and tactic acids (p<0.01) and higher contents of WSC and ethanol ( p < 0.01) than the control silage. When fed to wether sheep, the digestibilities of DM, organic matter and gross energy were not altered by additive treatment. The digestibility of modified acid-detergent fibre was lower for both the inoculated ( P < 0.01) and formic acid-treated silages ( p < 0.05). However, N retention was improved ( p < 0.05) by both additive treatments. Silage intake was improved ( p < 0.01) by additive treatment from 53.4 (control) to 58.0 (inoculated) and 60.4 (formic acid) g DM (kg live weight^0.75)^-1d^-1.