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ABSTRACT: Chub mackerel (34–35 cm, approximately 500 g), which were caught by fishing with a rod and line at the Bungo Channel, Oita prefecture, were rested overnight in a fish preserve and either killed by decapitation (control group) or allowed to struggle in air for 30 min (struggled group). Muscle samples were excised every 4 h, and measurements on breaking strength and histological observations were done for both groups. The breaking strength of muscle in the control group was significantly higher than that in the struggled group, whereby a decrease in breaking strength was delayed for 12 h compared to the struggled group. Light microscopy showed space extension among muscle cells in association with a decrease in breaking strength. Especially in the struggled group, the extended area was larger and the difference in area was significant at the time when breaking strength showed a significant difference. Using electron microscopy, the extended area showed cut and/or disappeared collagen fibrils. From these results, it was demonstrated that struggling to death promoted the degradation of collagen fibrils and the weakening of connective tissue and, resultantly, led to the faster softening of muscle of chub mackerel.  相似文献   
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Lindane analogs, in which one or two chlorine atoms are replaced by various substituents, exhibit convulsive and lethal effects on Periplaneta americana (L.). Some analogs are as active as lindane. These effects are well related to the neuroexcitatory action which produces after-discharges in the central nervous system. Carbamate insecticides have potent convulsive and lethal effects on P. americana, which are also related to after-discharges produced in nerve cords. Convulsion caused by lindane analogs and carbamates is solely attributable to their neuroexcitatory effects on the nervous system, in spite of the difference in their ultimate modes of action.  相似文献   
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The methane-mitigating potency of cashew nutshell liquid (CNSL) was evaluated by investigating gas production from batch cultures using feces from Thai native ruminants that had been incubated for different periods. Feces was obtained from four Thai native cattle and four swamp buffaloes reared under practical feeding conditions at the Kasetsart University farm, Thailand. Fecal slurry from the same farm was also included in the analysis. CNSL addition successfully suppressed the methane production potential of feces from both ruminants by shifting short chain fatty acid profiles towards propionate production. Methane mitigation continued for almost 150 days, although the degree of mitigation was more apparent from Day 0 to Day 30. Bacterial and archaeal community shifts with CNSL addition were observed in feces from both ruminants; specifically, Bacteroides increased, whereas Lachnospiraceae and Ruminococcaceae decreased in feces to which CNSL was added. Fecal slurry did not show marked changes in gas production with CNSL addition. The findings showed that the addition of CNSL to the feces of ruminants native to the Southeast Asian region can suppress methane emission. Because CNSL can be easily obtained as a byproduct of the local cashew industry in this region, its on-site application might be ideal.  相似文献   
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The growth and morphology of rumen methanogenic archaea (15 strains of 10 species in 5 genera, including 7 strains newly isolated in the present study) and bacteria (14 species in 12 genera) were investigated using unsupplemented in vitro pure cultures and cultures supplemented with cashew nut shell liquid (CNSL) and its phenolic compound components, anti-methanogenic agents for ruminant animals. Growth of most of the methanogens tested was inhibited by CNSL and alkylphenols at different concentrations ranging from 1.56 to 12.5 μg/ml. Of the alkylphenols tested, anacardic acid exhibited the most potent growth inhibition. Three gram-negative bacterial species involved in propionate production were resistant to CNSL and alkylphenols (>50 μg/ml). All the methanogens and bacteria that were sensitive to CNSL and alkylphenols exhibited altered morphology; disruption of the cell surface was notable, possibly due to surfactant activity of the tested materials. Cells division was inhibited in some organisms, with cell elongation and unclear septum formation observed. These results indicate that CNSL and alkylphenols, particularly anacardic acid, inhibit both rumen bacteria and methanogens in a selective manner, which could help mitigate rumen methane generation.  相似文献   
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The rumen microbiota comprises a vast range of bacterial taxa, which may affect the production of high-quality meat in Japanese Black cattle. The aim of this study was to identify core rumen microbiota in rumen fluid samples collected from 74 Japanese Black cattle raised under different dietary conditions using 16S rRNA gene amplicon sequencing. In the rumen of fattening Japanese Black cattle, 10 bacterial taxa, showing >1% average relative abundance and >95% prevalence, irrespective of the dietary conditions and the fattening periods, were identified as the core rumen bacterial taxa, which accounted for approximately 80% of the rumen microbiota in Japanese Black cattle. Additionally, population dynamics of the core rumen bacterial taxa revealed two distinct patterns: Prevotella spp. and unclassified Bacteroidales decreased in the mid-fattening period, whereas unclassified Clostridiales, unclassified Ruminococcaceae, Ruminococcus spp., and unclassified Christensenellaceae increased during the same period. Therefore, the present study reports the wide distribution of the core rumen bacterial taxa in Japanese Black cattle, and the complementary nature of the population dynamics of these core taxa, which may ensure stable rumen fermentation during the fattening period.  相似文献   
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