| As an important indicator for evaluating the health and development of animal husbandry,the immune function of livestock and poultry is a key issue that must be addressed in animal husbandry.With the widespread use of various electromagnetic devices in intelligent breeding and modern medical equipment,livestock and poultry are exposed to increasing magnetic fields,and the magnetic induction intensity is on the rise.While magnetic fields bring life support and economic benefits to the development of animal husbandry,their biological safety is also deserves our attention.Studies have indicated that magnetic fields may affect the immune function,antioxidant capacity,growth and development,reproductive performance,and egg production rate of livestock and poultry.Clarifying the effects of magnetic fields on livestock and poultry will help improve the management and production efficiency of animal husbandry.Elucidating the mechanism by which magnetic fields affect life activities is a prerequisite for further expanding the application of magnetic fields in animal husbandry and other fields.The influence of magnetic fields on immune function is worthy of further study and is currently one of the research hotspots in magnetobiology.Currently,there are a limited number of studies on the effects of magnetic fields on the immune function of livestock and poultry,and the conclusions are inconsistent.In particular,there are fewer studies on pigs,and most of them involve low-intensity dynamic magnetic fields,while there is almost no involvement in static magnetic fields(SMF)above 0.4 T.Research in this field urgently needs to be further strengthened and deepened.Considering the large size of livestock and poultry,and the narrow internal space of current strong magnetic field magnets,it is extremely inconvenient to process individuals at the magnetic field level.Therefore,this project selects pig alveolar macrophages(PAM)as the experimental research object to evaluate the effects of magnetic fields on the immune function of livestock and poultry at the cellular level.Combined with the laboratory’s research expertise,in Chapter 3,using the vertebrate model organism zebrafish with advantages such as small size,large flux,rapid development,and transparent larvae to conduct a systematic study,and then complete a comprehensive evaluation of the effects of magnetic fields on vertebrates at the individual,cellular,and molecular levels.The next two chapters use zebrafish live imaging,high-throughput transcriptome sequencing and other means to carry out research on the mechanism of magnetic field influence on immune function.The main research results are as follows:(1)In terms of the effects of magnetic fields on the immune function of PAM,experimental results indicate that 0.4 T SMF exposure for 2 hours has little effect on the state of PAM,but has a certain promoting effect on inflammatory responses.Specifically,magnetic field exposure has little effect on cell viability and phagocytic ability,but has a certain effect on the levels of intracellular NO and ROS.However,the intensity of the inflammatory response induced by LPS is weaker than that induced by the magnetic field.The promoting effect on the expression of pro-inflammatory cytokine-related genes such as TNF-α,IL-1β,IL-6,and IL-8 is obvious.(2)In terms of the effects of magnetic fields on zebrafish development,behavior,and immune function,research results indicate that the experimental magnetic field has little effect on zebrafish early development,and different magnetic field factors have different effects on behavior and immunity.The specific findings are as follows: exposure to0.4/3/22 T SMF for 2 hours,different durations of exposure to a 0.4 T SMF,and exposure to different directions of a 0.4 T SMF had no significant impact on the growth and development of zebrafish.The SMF reduced the locomotor activity of zebrafish;acute exposure for 2 hours significantly decreased the locomotor activity and visual responsiveness of zebrafish;An upward-directed SMF reduced locomotor activity and visual responsiveness,while a downward-directed SMF partially reduced locomotor activity and enhanced visual responsiveness.Exposure to a moderate-intensity SMF of 0.4T significantly increased inflammatory response,followed by exposure to a strong SMF of3 T,while exposure to an ultra-strong SMF of 22 T had almost no effect.Acute exposure for 2 hours had the most significant effect on enhancing inflammatory response,while chronic exposure for 24/72 hours had a lesser impact.An upward-directed SMF had a stronger effect on promoting inflammatory response than a downward-directed SMF.(3)In terms of the mechanism by which magnetic fields affect immune function,melatonin is involved in the influence of magnetic fields on immune function,and transcriptome sequencing also shows that 0.4 T SMF exposure for 2 hours promotes inflammatory responses in zebrafish larvae.The specific content is as follows: Acute exposure of 0.4 T SMF for 2 hours significantly affect the expression of the aanat2 gene,which may affect the secretion of melatonin in zebrafish larvae,thereby affecting the immune function of the body and altering the intensity of inflammatory response at the site of injury.Transcriptome sequencing provides us with information that tnfsf10l4,cxcl20,etc.may become key genes,and screens out possible influencing pathways such as Cytokine-cytokine receptor interaction,TNF signaling pathway,MAPK signaling pathway,etc.In summary,this study has constructed a set of controllable magnetobiology research models,conducted a systematic evaluation of the biological safety of SMF,and preliminarily elucidated the effect and mechanism of SMF on immune function.This paves the way for further development and application of magnetic fields in animal husbandry and life health and other fields;the study of magnetic induction mechanism lays the foundation for research on magnetic field regulation of immune function and facilitates the interdisciplinary integration of biology,physics,and medicine. |
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