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.     

不同酸泡菜中产细菌素植物乳杆菌的筛选

从6种泡菜中分离出217株乳杆菌,通过琼脂点扩散交叉拮抗试验,筛选出发酵液有抑菌作用的12株植物乳杆菌。排除了酸、过氧化氢的作用后,7株的离心发酵液对来自于甘蓝泡菜的1株植物乳杆菌Lactobacillus plantarum 96D 仍有抑菌活性,用胰蛋白酶对其处理后抑菌活性丧失,说明它们产生的抑菌物质是细菌素。其中 G_6,G_8,G_9和 H_(16)菌株抑菌效果较显著。     

Selection of lactic acid bacteria as candidate probiotics for Vibrio parahaemolyticus depuration in pacific oysters (Crassostrea gigas)

The application of probiotics in food is now widespread and is widely accepted by consumers. Lactic Acid Bacteria (LAB) were isolated from traditional salted fish and then characterized by its ability to inhibit Vibrio parahaemolyticus growth using minimal inhibitory concentration tests. Five out of these strains were identified as Lactobacillus delbrueckii, Lactobacillus casei and three Lactobacillus gasseri by PCR using 16S and 23S rRNA genes. Antibiofilm activity of Lactobacillus spp. extracts were also tested in 96 polystyrene plates. A potential antibiofilm effect was demonstrated as most LAB. Although most LAB extract were able to eradicate pre‐formed biofilm, results demonstrated that five Lactobacillus spp. exhibited a stronger inhibitory effect against V. parahaemolyticus in infected oysters. Vibrio parahaemolyticus viable cells number declined from 10⁶ UFC to 10⁴ UFC after 3 days of incubation with Lactobacillus spp. Probiotic applications, in biological control of seafood associated pathogens can be an alternative solution, providing consumer with a product of good quality owing to the use of non‐toxic compounds. Based on our results, LAB could be used as a bioprotective culture in oyster's depuration to prevent V. parahaemolyticus growth.     

Effects of the probiotic, Lactobacillus acidophilus, on the growth performance, haematology parameters and immunoglobulin concentration in African Catfish (Clarias gariepinus, Burchell 1822) fingerling

This experiment was carried out to evaluate the effects of the probiotic, Lactobacillus acidophilus , on the growth performance, haematology parameters and immunoglobulin concentration in African catfish Clarias gariepinus fingerling. Two experimental diets were formulated to contain 35 g kg⁻¹ crude protein and 10 g kg⁻¹ lipids accordingly and fed three times daily for 12 weeks to 25 C. gariepinus fingerlings per fibreglass tank in 12 replicates each. The control diet was prepared with no probiotic supplementation whereas the second diet was prepared supplemented with a probiotic, L. acidophilus , containing about 3.01 × 10⁷ colonies/g of diet. The results show that growth performance [specific growth rate (SGR) and relative growth rate (RGR)], nutrient utilization [protein efficiency ratio (PER) and feed conversion ratio (FCR)] and survival were significantly ( P <0.05) higher in fish maintained on the probiotic-supplemented diet compared with those on the control diet. Haematology parameters (packed cell volume, haemoglobin, erythrocyte sedimentation rate, red blood cell and white blood cell, total serum protein, Ca²⁺, Mg²⁺, Cl⁻, glucose and cholesterol) and total immunoglobulin concentrations were also significantly better in fish fed the probiotic-supplemented diet than in the control. Although the water quality parameters monitored were better in the fish fed the probiotic-supplemented diet than in the control, the parameters were not significantly different ( P >0.05). From the results of this experiment, we conclude that L. acidophilus can be used as a probiotic agent in African catfish culture, to enhance fish health, survival and better feed efficiency and growth performance.     

The effects of diet supplemented with Lactobacillus rhamnosus on tissue parameters of rainbow trout,Oncorhynchus mykiss (Walbaum)

This study was carried out to establish the effects of a 6 week treatment with the diet supplemented with L. rhamnosus in concentrations of 10⁷ CFU g^?1 (G1 group) and 10⁸ CFU g^?1 (G2 group) on the condition expressed by condition factors (Fulton's, Clark's and B), intestinal microbiology, haematological, histological and selected antioxidative parameters of rainbow trout. A significantly higher condition factors were found in G1 group indicating that higher concentration of probiotic (10⁸ CFU g^?1) did not result in the better condition. Cholesterol and urea levels were significantly higher in both G1 and G2 groups, albumin in G1 and creatinine in G2 group with respect to control. A significantly higher liver TBARS level was observed in G2 group. The feeding with supplemented probiont apparently changed the resident microbiota. Three weeks after withdrawal of the supplemented feed, the microflora mostly reverted to the control composition, although L. rhamnosus in faecal matter of fish remained inherent. The epithelial structure of the proximal and distal intestine revealed the increased absorptive area in both treated groups, as well as the increase in the mucin‐secreting goblet cells. The L. rhamnosus‐treated groups demonstrated the capacity for the augmentation of the innate host defence.     

Bacterial population in intestines of white shrimp,Litopenaeus vannamei fed a synbiotic containing Lactobacillus plantarum and galactooligosaccharide

The aims of this study were to unravel the intestinal microbiota of Litopenaeus vannamei after being fed a diet without (control) or with the synbiotic (SYN) for 60 days using next‐generation sequencing technology to see if changes in the intestinal microbiota were involved in the improved growth performance and health status of the shrimp. Next‐generation sequencing data showed that six phyla, 11 classes, 19 orders, 30 families, 58 genera and 73 species with taxonomic names assigned were detected. The majority of the operational taxonomic units (OTUs) was shared between the SYN and control shrimp and comprised 37 OTUs. However, intestinal biodiversity analyses revealed that SYN‐fed shrimp had a higher species richness, evenness and Shannon–Weaver index than did shrimp fed the control diet, but without reaching statistical significance. Interestingly, shrimp fed the SYN diet exhibited improved colonization of Lactobacillus plantarum and reduced prevalences of Vibrio harveyi and Photobacterium damselae in the intestines. These findings indicate that the SYN was able to modulate the intestinal bacterial community of shrimp and could be used to control vibriosis in shrimp.     

复合乳酸菌制剂对黄羽肉鸡生长性能、胃肠道pH、肠道形态和盲肠微生物的影响

本研究旨在探究复合乳酸菌制剂(CLP)对黄羽肉鸡生长性能、组织器官指数、胃肠道pH、肠道形态以及盲肠微生物数量的影响.选取1日龄体重相近、健康状况良好的黄羽肉鸡母鸡2100只,随机分成5组,每组6个重复,每个重复70只.对照组饲喂基础饲粮,抗生素组在基础饲粮中添加120 mg/kg的恩拉霉素,试验组分别在基础饲粮中添加...     

兰州百合粗低聚糖对嗜热链球菌ATCC-14485和保加利亚乳杆菌ATCC-11842产酸及增殖的影响

益生元在促进益生菌生长、调节肠道微生态平衡方面发挥着重要作用。为探究兰州百合粗低聚糖（crude lily oligosaccharides, CLOs）的益生元特性,以兰州百合干为原料,提取、表征CLOs;以低聚果糖和菊粉作为阳性对照,测定CLOs在人工胃肠溶液的水解度,以及对嗜热链球菌ATCC-14485和保加利亚乳杆菌ATCC-11842的产酸、增殖作用的影响。结果表明：CLOs分子量为1 194 Da,主要由甘露糖、阿拉伯糖和葡萄糖组成,摩尔比为1:3.57:16.40;CLOs经人工胃肠溶液消化后水解度是26.96%,显著低于菊粉（P <0.05）;CLOs促进乳酸菌发酵产酸的效果显著优于菊粉和低聚果糖（P <0.05）;当CLOs的添加量为1.0%(W/V)时,能有效促进嗜热链球菌和保加利亚乳杆菌的增殖,并减缓二者在货架期的死亡速率。研究结果说明CLOs具有益生元特性,可为新型共生发酵乳的研发提供理论依据。     

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.