Significance of earthworms in stimulating soil microbial activity

 The stimulatory effect of earthworms (Lumbricus terrestris L.) on soil microbial activity was studied under microcosm-controlled conditions. The hypothesis was tested that microbial stimulation observed in the presence of a soil invertebrate would be due to the utilization of additional nutritive substances (secretion and excretion products) that it provides. Changes in microbial activity were monitored by measuring simultaneously CO₂ release and protozoan population density. The increase in CO₂ released in the presence of earthworms was found to result from both earthworm respiration and enhanced microbial respiration. The stimulation of microbial activity was confirmed by a significant increase in protozoan population density, which was 3–19 times greater in the presence of earthworms. The respiratory rate of L. terrestris was estimated to be 53 μl O₂ g^–1 h^–1. Earthworm respiration significantly correlated with individual earthworm weight, but there was no correlation between the increase in microbial respiration and earthworm weight. This finding does not support the hypothesis given above that enhanced microbial respiration is due to utilization of earthworm excreta. A new hypothesis that relationships between microbial activity and earthworms are not based on trophic links alone but also on catalytic mechanisms is proposed and discussed. Received: 26 August 1997     

The Application of Microbiome Culturomics in Veterinary Medicine

Under laboratory conditions, the number of cultured microorganisms accounts for about 1% of the total number of microorganisms in nature, which limits people's understanding and utilization of 99% of the unknown microorganisms. However, relevant researches show that those "uncultured microorganisms" can be developed and utilized, and the uncultured microorganisms are the main body of the unknown microorganisms. The microbial culturomics explored the application of multiple culture conditions and long-term culture, it was combined with Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) and 16S ribosomal RNA (rRNA) sequencing to identify all kinds of microorganisms on a large scale. At the same time, whole-genome sequencing (WGS) and Metagenomics sequencing technology were used to analyze unknown microorganisms in depth. In this paper, the latest progress of culturomics in the ruminant gastrointestinal tract, poultry cecum, and livestock nasal microflora in recent years was reviewed, and the feasibility of applying the method of microflora culturomics in animal disease prevention and control was discussed. As a new research idea, culturomics has some immature aspects, but its development prospect is very broad. The complementary of microflora culturomics and other research methods have gradually become a breakthrough in the development of veterinary microbiology.     

芽孢杆菌制剂对艾维茵肉鸡胴体性能和肠道菌群的影响

试验选用7日龄艾维茵肉仔鸡480只,随机分为8组,每组3个重复,每个重复20只;选择适宜肉鸡饲喂的3种芽孢杆菌制剂,分别为枯草芽孢杆菌BS3(Bacillus subtilis 3)、产蛋白酶活力高的蜡样芽孢杆菌BC1(Bacillus cereus 1)和产纤维素酶活力高的蜡样芽孢杆菌BC2(B.cereus 2),将其单一或复合的添加到肉鸡日粮中,研究芽孢杆菌制剂对肉鸡胴体性能、免疫器官指数及肠道菌群的影响;8个试验组分别为对照组和BC1、BC2、BS3单一供给组及BC1+BC2、BC1+BS3、BC2+BS3、BC1+BC2+BS3 4个混合供给组,饲料中芽孢杆菌的添加量为3×105 CFU.g-1,混合组的配比为1∶1和1∶1∶1。结果表明:与对照组相比,添加BC1+BC2对提高肉鸡日增质量和降低料质量比效果显著(P<0.05),其中日增质量提高了9.97%,料质量比降低了8.46%;添加BC1和BC1+BC2组肉鸡的腿肌率分别提高了8.46%和7.95%(P<0.05),BC1、BC1+BC2和BC1+BC2+BS3组的腹脂率较对照组显著降低,分别降低了26.6%、30.2%和25.8%;日粮中添加BC1+BC2和BC1+BC2+BS3显著提高了脾脏指数(P<0.05),添加BC1+BC2、BC1+BS3和BC1+BC2+BS3组的法氏囊指数显著提高,添加BC1+BC2、BC1+BS3和BC1+BC2+BS3显著降低了肉鸡盲肠道内的大肠杆菌数(P<0.05)。本试验结果表明适用肉鸡的最佳芽孢杆菌制剂是BC1+BC2。     

低温沼气功能菌群的选育与试验

通过低温定向培养,从高纬、高寒野外厌氧环境样品和冬季沼气池底泥样品中分别选育出野生低温功能菌群和沼气池低温菌群。在13℃和10℃低温条件下,野生低温菌群产气率达到0.14 m3/d.m3和0.10 m3/d.m3,但所产沼气的甲烷含量较低,只有51.0%和48.0%。同样温度下,沼气池低温菌群的产气率只有0.06 m3/d.m3和0.04 m3/d.m3,但所产沼气的甲烷含量较高,达到62%和56%。两类菌群混合发酵可显著改善产气性能,相同温度下,产气率可达到0.15 m3/d.m3和0.11 m3/d.m3,高于两类菌群单独发酵,是常温菌群的3倍以上;混合低温菌群所产沼气的甲烷含量为57.0%和52.0%,介于野生低温菌群和沼气池低温菌群之间,比常温菌群提高19.0%和16.0%。研究结果表明,混合低温菌群具有较好的低温产气性能和广阔的应用前景。     

饲粮中添加乳铁蛋白对早期断奶仔猪生长性能、肠道菌群及肠黏膜形态的影响

本试验旨在研究在饲粮中添加乳铁蛋白(lactoferrin,LF)对断奶仔猪生长性能、肠道菌群及肠黏膜形态的影响。试验选用96头体重相近的21日龄"杜×长×大"三元杂交断奶仔猪,随机分为4组,分别饲喂基础饲粮(对照组)、基础饲粮+250 mg/kg乳铁蛋白、基础饲粮+500 mg/kg乳铁蛋白和基础饲粮+750 mg/kg乳铁蛋白,每组4个重复,每个重复6头仔猪。正试期21 d。结果表明,与对照组和750 mg/kg乳铁蛋白组相比,饲粮中添加250和500 mg/kg乳铁蛋白可显著提高仔猪平均日增重(P<0.05);与对照组相比,不同水平乳铁蛋白可显著降低盲肠中大肠杆菌数量(P<0.05),其中添加500 mg/kg乳铁蛋白显著提高了盲肠、结肠中乳酸杆菌的数量(P<0.05),显著降低了结肠中大肠杆菌数量(P<0.05);添加250和500 mg/kg乳铁蛋白极显著提高了十二指肠、空肠、回肠的绒毛高度/隐窝深度比值(P<0.01)。结果提示,饲粮中添加乳铁蛋白可刺激肠道有益菌生长、降低有害菌增殖,从而改善肠道功能,具有提高仔猪生长性能的作用,本试验条件下乳铁蛋白的适宜添加量为250 mg/kg。     

抗菌肽对蛋用仔公鸡血液免疫指标和肠道菌群的影响

本试验旨在研究饲粮中添加不同水平天蚕素抗菌肽对海兰褐蛋用仔公鸡血液免疫指标和肠道菌群的影响。选用336只1日龄健康海兰褐蛋用仔公鸡,随机分为7组,每组4个重复,每个重复12只鸡。各组分别饲喂基础饲粮(对照组)、基础饲粮+150 mg/kg金霉素(抗生素组)、基础饲粮+150、200、250、300、350 mg/kg抗菌肽(抗菌肽Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组),试验期为42 d。结果表明:1)抗菌肽Ⅳ、Ⅴ组免疫球蛋白A含量显著高于对照组和抗生素组(P<0.05);各组免疫球蛋白G含量显著高于对照组(P<0.05),抗菌肽Ⅱ、Ⅲ、Ⅳ、Ⅴ组免疫球蛋白G含量显著高于抗生素组(P<0.05);各组免疫球蛋白M含量差异不显著(P>0.05)。2)抗菌肽组补体3含量显著高于对照组和抗生素组(P<0.05),各组补体4含量差异不显著(P>0.05),抗生素组、抗菌肽Ⅲ、Ⅳ、Ⅴ组溶菌酶含量显著高于对照组(P<0.05)。3)各组大肠杆菌数量与对照组相比均显著降低(P<0.05),而抗菌肽Ⅲ、Ⅳ、Ⅴ组显著低于抗生素组(P<0.05);抗菌肽Ⅱ、Ⅲ、Ⅳ、Ⅴ组双歧杆菌数量与对照组相比显著提高(P<0.05);抗菌肽Ⅳ、Ⅴ组乳酸杆菌数量显著高于对照组(P<0.05),各抗菌肽组乳酸杆菌数量与抗生素组差异不显著(P>0.05)。由此可见,饲粮中添加不同水平抗菌肽可在一定程度上提高蛋用仔公鸡免疫力,增加肠道益生菌双歧杆菌和乳酸杆菌的数量,并能够有效降低肠道致病菌大肠杆菌数量,添加量为350 mg/kg时效果较好。     

A survey of feeding,management and faecal pH of Thoroughbred racehorses in the North Island of New Zealand

AIM: To identify feeding and management variables associated with variation in faecal pH within a population of intensively managed Thoroughbred racehorses in New Zealand.

METHODS: A cross-sectional survey was conducted of 16 racehorse trainers in the North Island of New Zealand. Interviews were conducted at the trainers' stables to obtain information on feeding and management of horses, and faecal samples were collected and faecal pH measured.

RESULTS: Ninety-seven percent of the horses surveyed were confined in an area ≤5 × 5 m for ≥12 h/day. Trainer's age, number of years they had trained horses, age and gender of horses, weeks in race training, racing class, frequency of feeding, bedding type, and exercise workload had no effect on mean faecal pH. Acidic faecal pH (pH ≤6.32) was associated with stables with ≤12 horses, and trainers at stables with ≤12 horses offered more concentrate feed than those at stables with >12 horses. Acidic faecal pH was associated with trainers who offered 4 kg of grain as the only form of concentrate fed, or offered ≤2.25 kg hay/day. Horses that displayed stable vices had less acidic faecal pH than horses that did not display stable vices, viz pH 6.70 (standard error of the mean (SEM) 0.135) vs 6.43 (SEM 0.029) (p=0.04).

CONCLUSIONS AND CLINICAL RELEVANCE: Racehorse management in New Zealand is similar to that observed in other major racing countries. Trainers with ≤12 horses fed more concentrates and their horses had lower faecal pH than those of trainers with >12 horses. Irrespective of management system, it appears important to provide at least 2.25 kg of hay/day ad libitum, to buffer hindgut acidosis associated with diets high in soluble carbohydrate.     

Has the optimum time for faecal nematode egg count reduction testing in sheep in New Zealand changed?

Abstract

AIM: To determine what, if any, changes have taken place in the optimum time, for undertaking faecal egg count reduction tests (FECRT) in sheep in New Zealand.

METHODS: A comparison was made between the numbers and types of nematode genera adequately represented for testing purposes (faecal nematode egg count (FEC) of >50 epg) in initial FECRT case submissions to a veterinary laboratory in New Zealand, during two 4-year periods, in 1992–1995 and 2006–2009.

RESULTS: Although there were some minor differences between them, the seasonal patterns of occurrence remained basically the same for all parasite genera in both datasets, with their individual peak periods of representation occurring during February to May in all instances. Not surprisingly, this period of maximum seasonal occurrence for each parasite genus also coincided with those months of the year when the greatest numbers of worm genera were adequately represented for faecal nematode egg count reduction (FECR) testing.

CONCLUSIONS: The results of this study indicate that the optimum time for conducting FECRT in sheep in New Zealand continues to be during the late summer-autumn months of February to May. However, they also reaffirmed that even during this optimal period there are still likely to be many occasions when relatively few nematode genera may be sufficiently well represented for satisfactory FECR testing. Accordingly, veterinary practitioners ought to be aware that, in order to obtain a complete picture of the resistance status of all worm genera on a particular property, such testing may need to be carried out on more than one occasion.     

Field studies investigating anthelmintic resistance in young cattle on five farms in New Zealand

AIM: To investigate the efficacy of pour-on anthelmintics against field strains of parasitic nematodes in young cattle on five farms in New Zealand.

METHODS: Faecal nematode egg count (FEC) reduction (FECR) tests were carried out on five calf-rearing farms using pour-on formulations of levamisole, ivermectin, eprinomectin, and the simultaneous administration of levamisole and ivermec- tin. Faecal samples were collected per rectum before treatment and about 7, 14, 21 and 28 days after treatment, for FEC and faecal nematode larval culture.

RESULTS: Resistance (i.e. <95% reduction in FEC) of Cooperia oncophora to ivermectin and eprinomectin was identified on all five farms. There was limited evidence of possible emerging resistance in Ostertagia spp to ivermectin but not eprinomectin, in short-tailed larvae of Cooperia spp to ivermectin and eprinomec- tin, and in Trichostrongylus spp to ivermectin, eprinomectin and levamisole used separately. Levamisole was effective against C. oncophora, but had variable efficacy against Ostertagia spp in the calves in this study. Simultaneous treatment with levamisole and ivermectin pour-on formulations were effective against all genera on all farms.

CONCLUSIONS: To effectively manage roundworm parasites in their calves farmers need to be aware of the resistance status of the parasites on their farms. Levamisole is likely to be an effective anthelmintic on most farms at times of the year when the impact of Ostertagia spp is not high. Simultaneous administration of levamisole and ivermectin pour-on anthelmintics to cattle is likely to control both ML-resistant C. oncophora and stages of Ostertagia spp that are not controlled by levamisole alone.     

Effect of Daidzein on Ileum Microflora Biodiversity in Hy-Line Variety Brown Layers

Daidzein is always added into poultry feed to make the production performance and immunity of poultry better. In this study, a total of 600 40-week-old Hy-Line variety brown layers were randomized into five groups and fed with a corn-soybean-mixed basal diet supplement with 0, 10, 50, 100, and 500 mg · kg^-1 daidzein, respectively. Then, two PCR-based typing methods（RAPD-PCR and ERIC-PCR） were combined to analyze the ileum content and explore the changes of ileum microflora biodiversity. The results of RAPD-PCR and ERIC-PCR showed that bands under 10 mg · kg^-1 and 50 mg · kg^-1 were the most, and their similarity was the largest. Bands under 500 mg · kg^-1 were the least and similarity with other groups was the minimum. Ileum microflora biodiversity under 10 mg · kg^-1 or 50 mg · kg^-1 was richer than that under 500 mg · kg^-1. A corn-soybean-mixed basal diet supplement with 10 mg · kg^-1 to 50 mg · kg^-1 of daidzein might be beneficial to Hy-Line variety brown layers intestinal bacteria.