This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa Whi...This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa White layers, were subdivided into six treatments of 32 individually caged birds. Half of the birds were reared under regular temperature conditions, while the other half was subjected to cyclic daily heat stress. Layers were offered one of three diets: 1) Control;2) Control + Lactobacillus plantarum RS5 probiotic;3) Control + Lactobacillus plantarum RS5 postbiotics. Birds were tested for performance and visceral organ development for 5 months. Heat stress negatively affected the birds’ feed intake, egg weight, shell weight percentage, Haugh unit, shell thickness, yolk color, body weight and spleen weight percentage. Postbiotics significantly increased egg production (p < 0.05) in comparison to the control and the probiotic fed group (94.8% vs 92.6% vs 93.1%, respectively). Birds under probiotic or postbiotic diet showed a significantly higher (p < 0.05) feed intake and egg weight, although the probiotic had a more pronounced and gradual effect. Specific gravity, yolk weight percentage and shell thickness didn’t show differences among dietary groups. The Haugh Unit was significantly higher (p < 0.05) in probiotic group which also showed a significantly lower yolk color index (p < 0.05). The different feed treatments did not impact the bird’s viscera weight percentage, except for the ileum that was significantly lower (p < 0.05) under postbiotic supplementation. Both probiotics and postbiotics could be used as a potential growth promoters and might alleviate heat stress impact in poultry industry.展开更多
It is a common phenomenon that there exists shallow geotemperature rise precursor around an earthquake region before the event occurs. The existing models on geotemperature precursor mechanism such as the deep thermal...It is a common phenomenon that there exists shallow geotemperature rise precursor around an earthquake region before the event occurs. The existing models on geotemperature precursor mechanism such as the deep thermal ascent model and the model of hothouse effect, all encounter some contradictions although there is a certain evidence supporting them. From the angle of dissipative heat in the present paper, we set forth a new interpretation model named the stress-dissipative heat model with the main points of view as: the dissipative heat transformed from the work of crustal stress to non-elastic deformation of rock and soil, is one important reason for preseismic geotemperature rise. The medium-term regional and tendency geotemperature rise before an earthquake closely relates to the intensification of regional crustal stress field; the short-term and prequake geotemperature bursting rise around an earthquake region closely relates to rapid change of the source stress field. Plastic deformation and dissipative heat is much easier created in soil than rock. Therefore, the pre-earthquake geotemperature precursors mainly appear in soil covered area and mostly concentrate in shallow soil layers.展开更多
文摘This experiment was conducted to determine the performance of heat-stressed layers fed a diet containing the probiotic Lactobacillus plantarum RS5 or its products of fermentation (postbiotics). Twenty-week-old Isa White layers, were subdivided into six treatments of 32 individually caged birds. Half of the birds were reared under regular temperature conditions, while the other half was subjected to cyclic daily heat stress. Layers were offered one of three diets: 1) Control;2) Control + Lactobacillus plantarum RS5 probiotic;3) Control + Lactobacillus plantarum RS5 postbiotics. Birds were tested for performance and visceral organ development for 5 months. Heat stress negatively affected the birds’ feed intake, egg weight, shell weight percentage, Haugh unit, shell thickness, yolk color, body weight and spleen weight percentage. Postbiotics significantly increased egg production (p < 0.05) in comparison to the control and the probiotic fed group (94.8% vs 92.6% vs 93.1%, respectively). Birds under probiotic or postbiotic diet showed a significantly higher (p < 0.05) feed intake and egg weight, although the probiotic had a more pronounced and gradual effect. Specific gravity, yolk weight percentage and shell thickness didn’t show differences among dietary groups. The Haugh Unit was significantly higher (p < 0.05) in probiotic group which also showed a significantly lower yolk color index (p < 0.05). The different feed treatments did not impact the bird’s viscera weight percentage, except for the ileum that was significantly lower (p < 0.05) under postbiotic supplementation. Both probiotics and postbiotics could be used as a potential growth promoters and might alleviate heat stress impact in poultry industry.
文摘It is a common phenomenon that there exists shallow geotemperature rise precursor around an earthquake region before the event occurs. The existing models on geotemperature precursor mechanism such as the deep thermal ascent model and the model of hothouse effect, all encounter some contradictions although there is a certain evidence supporting them. From the angle of dissipative heat in the present paper, we set forth a new interpretation model named the stress-dissipative heat model with the main points of view as: the dissipative heat transformed from the work of crustal stress to non-elastic deformation of rock and soil, is one important reason for preseismic geotemperature rise. The medium-term regional and tendency geotemperature rise before an earthquake closely relates to the intensification of regional crustal stress field; the short-term and prequake geotemperature bursting rise around an earthquake region closely relates to rapid change of the source stress field. Plastic deformation and dissipative heat is much easier created in soil than rock. Therefore, the pre-earthquake geotemperature precursors mainly appear in soil covered area and mostly concentrate in shallow soil layers.
