Investigation On Cadmium Pollution In The Environment Of Chicken Farm In A Certain District And Assessment On Nano-Selemium Antagonized Cadmium-Induced Cerebellar Injury In Chickens

With the rapid development of modern battery,metal and other industries,the heavy metal cadmium(Cd)has become a widespread environmental pollutant,and its accumulation in brain causes neurodegenerative diseases and central nervous system dysfunctions that attract widespread attention.Epidemiological investigations have shown that level of Cd exposure is positively correlated with the degree of damage to the nervous system of animals,but there are few studies on its harm to the central nervous system of poultry.In order to reveal the toxic mechanism of Cd toxicity to the central nervous system of poultry,in this study,used ICP-MS and flame atomic absorption spectrophotometer to investigate the accumulation of Cd in poultry's central nervous system.In order to reveal the toxicity of feed Cd pollution on chicken cerebellum,and to explore the protective effect of Cd-selenium and Cd on chicken neurotoxicity,1-day-old Hyline white chickens were used as the research object and randomly divided into 6 groups(20 per group),namely Control group(basic diet),Nano-Se group(basic diet+1 mg/kg Nano-Se),35 mg/kg Cd group(basic diet+35 mg/kg Cd),70 mg/kg Cd group(basic diet+70mg/kg Cd),140mg/kg Cd group(basic diet+140mg/kg Cd)and Nano-Se+Cd group(basic diet+1mg/kg Nano-Se+140mg/kg Cd),fed for 90 days,to observe the pathological changes in of the cerebellum,detect the content of five elements in the cerebellum,antioxidant function,expression of selenoprotein and selenoprotein synthesis related factors,heat shock response,MTF1-mediated metal response,and so on.Research indicates:(1)Environmental investigations showed that 8.54%of farmland soil samples in the chicken farm environment of a certain city contained Cd content higher than 3mg/kg;Survey on the Cd content of farmland irrigation water in chicken farms The results showed that the Cd content of 49irrigation water samples was higher than the national standard for farmland irrigation water quality standard value,the exceeding rate was 12.96%;the sample survey of feed samples showed that the sample Cd exceeded the standard rate of 7.66%,of which the Cd content of the most exceeded samples 19.8 mg/kg;(2)Cd exposure caused a decrease in the content of selenium,iron,zinc and other elements in the chicken cerebellum,and an increase in the content of Cd and copper,indicating that Cd caused an imbalance in the homeostasis of the chicken cerebellum;after the intervention of Nano-Se,the selenium,iron,The changes in the content of five elements such as zinc,Cd,and copper show that Nano-Se can cause the imbalance of element homeostasis in chicken cerebellum tissue when exposed to Cd;(3)Cd exposure caused pathological changes such as the decrease in the number of Purkinje cells in the chicken cerebellum,the pyknosis of neuronal nuclei,and the blurred nucleolus,indicating that Cd exposure caused damage to the chicken cerebellum.Purkinje cell was increased after the intervention of Nano-Se.The number of Purkinje cells reduces the shrinkage of neuronal nuclei,showing that Nano-Se can protect chicken cerebellar tissue changes caused by cadmium exposure;(4)Cd exposure leads to increased MDA and H₂O₂ content,decreased T-AOC capacity,and decreased CAT,T-SOD and GSH-PX activities,indicating that Cd exposure can cause oxidative stress in the chicken cerebellum;Nano-Se intervention reduces Cd exposure.The induced increase in MDA and H₂O₂ content significantly improves T-AOC capacity,CAT,T-SOD and GSH-PX antioxidant enzyme activities,indicating that Nano-Se can alleviate the oxidative stress of chicken cerebellum caused by Cd exposure;(5)Cd exposure caused 6 selenoprotein synthesis factors(Sep Sec S,SBP2,Secp43-1,SARS,SPS and PSTK)and 24 selenoproteins to decrease in varying degrees,including Sep Sec S,SBP2,SARS,SPS,PSTK,Dio1,The decrease in Dio2,Dio3,Gpx2,Gpx3 and Selt expressions was the most obvious,indicating that Cd reduces the expression of selenoprotein by inhibiting selenoprotein biosynthesis related factors;the intervention of Nano-Se increased the expression of selenoprotein synthesis factor and selenoprotein,indicating that Nano-Se can antagonize Cd exposure causes disorder of selenoprotein transcriptome of chicken cerebellum;(6)Medium and low doses of Cd exposure activated the expression of heat shock response factors(HSF1,HSF2,HSF3,HSP10,HSP25,HSP27,HSP40,HSP47,HSP60,HSP70,HSP90,and HSP110),and high dose of Cd exposure inhibited the expression of factors related to the heat shock response,indicating that the heat shock response was activated under low-and medium-dose Cd exposure,and high-dose Cd exposure induced chicken cerebellar toxicity by inhibiting the heat shock response;Nano-Se intervention significantly activated Cd Inhibited heat shock response,indicating that Nano-Se regulates the heat shock response response to the chicken cerebellar injury induced by Cd exposure;(7)Low-dose Cd exposure activates the expression of MTF1-mediated element homeostasis regulation signaling pathway related factors(MTF1,MT1,MT2,DMT1,ZIP8,ZIP10,TF,and ATP7B),while medium and high-dose Cd exposure inhibits the expression of related factors(MTF1,MT1,MT2,DMT1,ZIP8,ZIP10,TF,and ATP7B).MTF1-mediated element homeostasis regulation signal pathway related factors,indicating that under low-dose Cd exposure,the MTF1-mediated element homeostasis regulation signal pathway can regulate the transport of related metal ions,play the role of element homeostasis regulation,and protect Cd causes damage to the cerebellum of chickens,while medium and high doses of Cd have the opposite effect,causing damage to the cerebellum of chickens.Nano-Se intervention activates this pathway,and selenoproteins Selw and Selh are the key targets of MTF1 expression.We speculate that Nano-Se regulates element homeostasis by activating the expression of selenoproteins and MTF1-mediated element homeostasis.Reduce cerebellar damage in chickens caused by Cd exposure;In summary,there are varying degrees of excessive Cd content in chicken farms in a city,and Cd exposure can cause depression,decreased feed intake,and even neurological symptoms in some chickens.Animal experiments have found that Cd exposure can cause pathological changes in the cerebellum,resulting in imbalance of element homeostasis,oxidative stress,inhibition of heat shock response,selenoprotein-related factors and MTF1-mediated element homeostasis regulation signal pathway related factors The expression,which in turn leads to chicken cerebellar damage.The intervention of Nano-Se reduced the cerebellar damage caused by Cd to a certain extent.This experiment enriches the research of Cd-induced cerebellar toxicity in chickens,provides practical guidance for the scientific prevention and control of Cd pollution in the poultry industry,and also provides a theoretical basis for the development of potential therapeutics against Cd poisoning.