复合乳酸菌制剂的耐受性和抑菌性研究

本试验将四株饲用乳酸菌,制成复合乳酸菌制剂,通过单因素试验设计,以存活率为指标,研究复合微生态产品对高温、酸、胆盐的耐受性,采用琼脂稀释法、牛津杯法分别测定复合乳酸菌制剂对不同种类饲用抗生素的耐受性及对致病菌的抑制作用。结果表明:复合乳酸菌产品在温度65℃处理2.5、5、7.5 min以及85℃处理2.5 min对其存活率没有影响,但当85℃处理5 min,存活率下降至48%;p H为3时处理90 min存活率高达80.54%。对0.3%猪胆盐的耐受性较好,处理1 h存活率为73.52%;对抗生素(药物饲料添加剂)杆菌肽锌、亚甲基水杨酸杆菌肽耐受性最强,对吉他霉素的耐受性最差;可抑制致病菌株大肠埃希氏菌的生长。体外评价试验结果表明,复合乳酸菌制剂具有很好的益生特性,可进一步研究其在动物上的应用效果。     

耐镉乳酸菌对蛋鸡生产性能及蛋品质的影响

为研究日粮中分别或同时添加镉和具有耐镉特性的约氏乳酸杆菌对如草蛋鸡生产性能和蛋品质的影响,试验分为5组:对照组、镉组(Cd 5 mg/kg)、低剂量乳酸菌组(Lac 1×10¹⁰cfu/kg)、镉加低剂量乳酸菌组(Cd 5 mg/kg+Lac1×10¹⁰cfu/kg)、镉加高剂量乳酸菌组(Cd 5 mg/kg+Lac 1×10¹¹ cfu/kg)。试验期6周,全程统计分析蛋鸡日采食量、产蛋量、产蛋率和料蛋比。在试验的3周末和6周末各组连续收集三天的鸡蛋,测定蛋品质。结果显示:镉加低剂量乳酸菌组的产蛋量、产蛋率较对照组和镉组分别提高38%、16.22%和5.3%、2.44%,料蛋比降低1.09和0.17。6周时镉加低剂量乳酸菌组的蛋重为48.8 g,较低剂量乳酸菌组提高7.3%(P <0.05);而其蛋白高度较对照组和镉组分别提高24.4%和18.6%(P <0.05)。蛋黄色泽在3周时,各试验组比对照组低1～3级(P <0.01),而在6周时,各试验组比对照组高2～3级(P <0.01)。6周时镉组和镉加高剂量乳酸菌组的蛋黄质量均较低剂量乳酸菌组提高7.9%(P <0.05),而其蛋黄蛋白比均较对照组高12.3%(P <0.01),较低剂量乳酸菌组和镉加低剂量乳酸菌组提高8.5%和6.7%(P <0.05)。蛋壳厚度在3周时,试验组较对照组低0.01～0.02 mm(P <0.01)。蛋壳颜色L在3周和6周时,镉组较对照组值分别降低了4.9%和7.4%(P <0.05);蛋壳颜色a在3周和6周时,镉组较对照组分别提高63.3%和66.7%(P <0.01),在6周时镉组较低剂量乳酸菌组和镉加低剂量乳酸菌组分别提高26.8%和28.6%(P <0.05);蛋壳颜色b在3周时,试验组较对照组分别提高36.5%、25.3%、27.0%和26.4%(P <0.01),在6周时镉组较对照组提高15.4%(P <0.01)。综上,在蛋鸡低镉饲粮中添加1×10¹⁰cfu/kg的耐镉乳酸菌可提高蛋鸡的生产性能,且显著增加蛋白高度。     

补喂复合益生菌对3～6月龄伊犁马粪便纤维含量、挥发性脂肪酸浓度和血浆细胞因子水平的影响

试验旨在研究补喂复合益生菌对3～6月龄伊犁马粪便纤维含量、VFA浓度和血浆细胞因子水平的影响。选取体重相近(90.23kg±11.02kg)、健康状况良好的3月龄伊犁马哺乳马驹10匹,随机分为2组,每组5匹,分别为对照组和试验组。在分阶段补喂等量营养水平的精料补充料和苜蓿干草的基础上,试验组每匹马驹每天补喂0.075g(2×10¹¹ CFU/g)枯草芽孢杆菌和0.133g(3×10¹⁰ CFU/g)植物乳杆菌复合菌,进行为期90d的饲养试验。结果显示,补喂复合益生菌能够显著或极显著降低马驹粪便中酸性洗涤纤维(ADF)和淀粉的含量(P<0.05;P<0.01),分别比对照组低3.50%和11.32%;显著或极显著提高马驹粪便中乙酸和丙酸的浓度(P<0.05;P<0.01),分别比对照组高14.65%和64.29%;极显著提高血浆中肿瘤坏死因子α(TNF-α)的水平(P<0.01),比对照组高16.17%。由此可见,补喂复合益生菌能够降低马驹粪便中纤维的含量、提高挥发性脂肪酸(VFA)的浓度,增加3～6月龄伊犁马血浆细胞因子水平。     

Lactobacillus parafarraginis ZH1 producing anti‐yeast substances to improve the aerobic stability of silage

Enhancing the aerobic stability of silage is very important in silage production. The objective of this study was to compare the roles of a new bacterial strain Lactobacillus parafarraginis ZH1 with Lactobacillus plantarum Chikuso‐1 (LP) and Lactobacillus buchneri NCIMB 40788 (LB) in improving the aerobic stability of oat silage and identify the anti‐yeast substances produced by them. After ensiled for 45 days, either inoculated silages or control silage were of pH values lower than 4.2. The control and LP inoculated silage had poorer aerobic stability than LB and ZH1 inoculated ones (p < 0.05). ZH1 inoculated silage produced more acetic acid, benzoic acid and hexadecanoic acid than LB inoculated one and had the best aerobic stability (p < 0.05). In MRS medium, strain ZH1 produced more hexadecanoic acid than LP and LB strains, more benzoic acid than strain LP (p < 0.05), and the equal amount of benzoic acid to LB (p > 0.05). In addition, benzoic acid and hexadecanoic acid had low minimal inhibitory concentrations to target yeasts in the pure culture. In conclusion, L. parafarraginis ZH1 had stronger anti‐yeast potential and more effectively improved the aerobic stability of silage than other strains used in this study.     

产胆盐水解酶植物乳杆菌降胆固醇作用的研究

采用茚三酮显色法测定了5株具有潜在益生特性的植物乳杆菌的胆盐水解酶(BSH)活性,采用邻苯二甲醛法测定了发酵上清液、菌体洗涤液和菌体破碎液中胆固醇含量,并对二者进行了相关性分析。结果表明,5株菌的BSH比活力为0.0149~0.0299U/mg总蛋白,去除胆固醇能力为37.64~47.88μg/mL。5株乳杆菌BSH活性与菌体洗涤液中胆固醇含量呈显著正相关,推断是菌株BSH水解结合胆盐生成游离胆酸,后者与胆固醇共沉淀,从而达到降胆固醇的效果。上述研究结果为利用益生菌生产具有降胆固醇功效的产品提供了理论依据。     

Autochthonous probiotic as growth promoter and immunomodulator for Astyanax bimaculatus cultured in water recirculation system

This work aimed to evaluate the probiotic Lactobacillus spp. in the microbiota of Astyanax bimaculatus reared in a water recirculation system. The experiment was randomized, using 800 postlarvae distributed into eight polyethylene containers, separated into two treatments, in quadruplicate: supplementation with Lactobacillus spp. (Probiotic) and no supplementation (Control). After 90 days of culture, 13 fish per container were anaesthetized. Three of these underwent microbiological evaluation, and haematological analyses were carried out on five. Immunological assessment was performed on another five fish. Zootechnical parameters were evaluated for all animals. In the microbiological evaluation, the probiotic group presented higher counts of lactic acid bacteria, but lower counts of Vibrio spp., Pseudomonas spp., and Staphylococcus spp., when compared with control. After haematological analysis, the supplemented group presented low haematimetric indices of Mean Corpuscular Haemoglobin Concentration and Mean Corpuscular Haemoglobin (MCHC and MCH, respectively) and higher amounts of total leucocytes, thrombocytes and circulating monocytes when compared with control. The immunological profile did not differ between treatments. In the zootechnical performance, probiotic group presented higher productivity, survival and apparent food efficiency when compared with control. Therefore, when Lactobacillus spp. was supplemented in the diet of A. bimaculatus, immunocompetence and the zootechnical performance of animals increased.     

添加嗜酸乳杆菌对凡纳滨对虾生长、酶活性及相关酶mRNA表达的影响

本实验旨在研究饲料中添加嗜酸乳杆菌(Lactobacillus acidophilus)对凡纳滨对虾(Litopenaeus vannamei)幼虾生长、非特异性免疫酶活性、抗病力和相关酶m RNA表达的影响。选取840尾初始均重为(0.58±0.01)g的凡纳滨对虾幼虾为研究对象,分为7个处理,每个处理3个重复。投喂添加不同比例(0%,0.1%,0.2%,0.4%,0.6%,0.8%,1.0%)嗜酸乳杆菌的饲料,养殖期8周。结果显示:添加不同比例嗜酸乳杆菌对凡纳滨对虾的成活率无显著影响(P0.05)。增重率与特定生长率随添加量的增加呈先上升后下降的趋势,但均显著高于对照组(P0.05),在0.4%组达到最大值;当添加0.2%时,饲料系数最低,其他各组显著低于对照组(P0.05),而蛋白质效率的变化规律则与饲料系数相反。血清酚氧化物酶(phenoloxidase,PO)、碱性磷酸酶(alkaline phosphatase,AKP)和酸性磷酸酶(acid phosphatase,ACP)活性随添加量的增加先升高后降低,分别为0.4%、0.1%和0.2%时,达到最大值。过氧化氢酶(catalase,CAT)、溶菌酶(lysozyme,LZM)和超氧化物歧化酶(superoxide dismutase,SOD)活性,实验组均显著高于对照组(P0.05)。实验组过氧化氢酶(CAT)m RNA表达量和溶菌酶(LZM)m RNA表达量均显著高于对照组(P0.05)。哈维弧菌(Vibrio harveyi)攻毒96 h,对虾存活率随添加量的增加显著升高(P0.05)。以增重率(weight gain rate,WGR)为判断依据,根据折线模型得出,饲料中添加0.23%嗜酸乳杆菌可显著促进凡纳滨对虾生长,并提高非特异性免疫酶活性。     

嗜酸乳杆菌高密度发酵研究进展

嗜酸乳杆菌是一种具有重要商业价值的益生菌,嗜酸乳杆菌的高密度发酵技术对于该菌的工业化生产有重要应用价值。本文对嗜酸乳杆菌的营养需求、冷冻环境适应策略以及高密度发酵探索等方面的研究进行综述,旨在为嗜酸乳杆菌的生产提供理论参考。     

Lactic acid bacteria strains for enhancing the fermentation quality and aerobic stability of Leymus chinensis silage

Leymus chinensis is an important grass in China and Russia. Six lactic acid bacteria (LAB) strains (LB, LPL1, LPL2, LPL3, LCL and WH) from L. chinensis silage were screened and identified and their effects on fermentation quality were investigated. All six strains were grown at 6·5% NaCl and pH 4·00. Strains LPL1, LPL2 and LPL3 were identified as Lactobacillus plantarum, and LB, WH and LCL were classified as Lactobacillus brevis, Weissella hellenica and Lactobacillus casei respectively. The six isolated strains and a commercial inoculant (Lactobacillus buchneri) were added to L. chinensis for ensiling at densities of 500 and 600 kg m^?3. The control was sprayed with the same volume of distilled water. The effects of the strains on fermentation quality after 45 d ensiling and aerobic stability during 8 d of exposure to air were evaluated. The 600 kg m^?3 silage had lower pH, butyric acid, ammonia nitrogen content and coliform bacteria counts than the 500 kg m^?3 density silage (P < 0·05). The six isolated strains decreased pH, butyric acid content and increased lactic acid content, and all inoculants increased L. chinensis silage aerobic stability except LCL (P < 0·05). The fermentation quality of L. chinensis silage increased with higher ensiling density. The LAB strains improved the fermentation quality, and high‐quality silage could be obtained at low ensiling density with the addition of the LAB strains. The strains improved the aerobic stability; Lb. buchneri and Lb. brevis showed the best performance.     

Effects of ethanol,molasses and Lactobacillus plantarum on fermentation characteristics and aerobic stability of total mixed ration silages

This study was conducted to evaluate the effects of Lactobacillus plantarum, molasses and/or ethanol on fermentation quality and aerobic stability of total mixed ration (TMR) silage, which is widely used in dairy cow diets at mid‐to‐late lactation in Tibet. TMR was treated with ethanol (E), molasses (M), Lactobacillus plantarum(L), ethanol+molasses (EM), ethanol+Lactobacillus plantarum (EL) plus control. After 45 d of ensiling, inoculant significantly (P < 0·05) increased lactic acid (LA) concentration and decreased pH, ammonia nitrogen (AN) concentration, and aerobic bacterial and yeast counts, compared to control. After the first 3 d of aerobic exposure, LA for silages without ethanol started to decrease, while LA for E silages almost remained unchanged till the end of the aerobic exposure period. The pH in TMR silages without ethanol gradually increased, while that for E and EL remained about 4·60 and 4·00, respectively, and EL showed the lowest pH among six silages over the course of aerobic exposure. Aerobic bacterial counts in control, M and EM silages were significantly higher (P < 0·05) than those in E, L and EL, and yeast counts in E and EL silages were significantly lower (P < 0·05) than those in other silages after 9 d of aerobic exposure. The results suggest that inoculation with L. plantarum was more effective in altering fermentation characteristics than adding molasses, while ethanol showed a potential to protect TMR silages from pH increase and delayed the growth of aerobic bacteria and yeast either alone or in combination with L. plantarum.