Comparison of Bacterial Flora in a Methane Fermentation Plant in Field Science Center at Tohoku University and Bovine Rumen Used as the Plant Microbial Resource by 16S rRNA Gene Sequencing

Poster Sessio

ラット フツウ フン ト ガンスイ フン チュウ ノ ビ セイブツ ソウ

3週齢のSD系雄性ラット12匹を食糞行動を許容した対照区と食糞行動阻止区に6匹ずつ配し,4週間の飼育期間中に,対照区からは普通糞を,食糞行動阻止区からは含水糞を採取し,それぞれの糞の微生物数を測定した。普通糞では含水糞に比べStaphylococciとVeillonellaeが多く,StreptococciとBacteroidaceaeが少ないことが明らかとなった。普通糞と含水糞で微生物叢が異なることは,含水糞に含まれるビタミン類の合成や消費に関わるものと考えられた。Hydrous feces were ingested by rats in coprophagous behavior. Twelve healthy male Sprague-Dawley strain rats (3 weeks old) were divided into a control group (coprophagy-allowed) of 6 rats and a coprophagy-prevented group of 6 rats. The usual feces from the control group and the hydrous feces from the coprophagy-prevented group were collected during 4 weeks of the experimental period. The viable number of microorganisms in the feces was estimated. The numbers of Staphylococci and Veillonellae, in the usual feces were higher than those of the hydrous feces. Furthermore, the numbers of Streptococci and Bacteroidaceae in the usual feces were lower than those of the hydrous feces. The differences of microflora between the usual feces and hydrous feces seemed to relate to the synthesis and consumption of vitamins in hydrous feces

Nurmi-type Culture Prepared using Culture Media without L-Cysteine Enhances Salmonella Exclusion in Hatched Layer Chicks

To determine the influence of media composition on Salmonella exclusion of Nurmi-type cultures, two and four types of cultures in the first and second trial, respectively, were prepared from the cecal contents of conventional laying hens, and Salmonella exclusion was assessed in newly hatched chicks. In the first trial, modified Viande Levure (VL) broth or nutrient broth (NB) were used to prepare Nurmi-type cultures (N-VL and N-NB), which were administered to the newly hatched chicks. Twenty-four hours later, the chicks were challenged with Salmonella enterica Typhimurium EF85-9 (ST). ST recoveries (log10 colony forming units/g of cecal contents) from the N-VL-, N-NB-, and control-treated groups 5 days after the challenge were 7.6±0.6, 0.9±1.9, and 7.7±0.4, respectively. The results suggested the influence of L-cysteine (Cys) present in the VL broth. Thus, we determined the effect of Cys in the second trial. We prepared two other cultures using VL broth without Cys (N-VL—Cys) and NB with Cys (N-NB＋Cys). ST recoveries from the cecal contents of the N-VL-, N-VL—Cys-, and control-treated groups were 6.3±0.9, 2.1±2.5, and 9.2±0.8, respectively. ST was not recovered from the N-NB- and N-NB＋Cys-treated groups. To identify bacteria with Salmonella exclusion activity, we isolated 41 bacterial strains from the ceca of N-NB-treated chicks without Salmonella challenge. Most isolates were identified as Enterococcus faecalis or E. mundtii based on 16S rRNA gene sequencing, and only four cultures excluded Salmonella. Therefore, VL broth containing Cys was not always required for preparing Nurmi-type cultures. The use of media prepared with Cys at the lowest possible concentration or without Cys would promote to enhance Salmonella exclusion from Nurmi-type cultures