Investigation Of Cadmium Content In Chicken Feed In Heilongjiang Province And Study On Damage To Chicken Spleen

Cadmium(Cd)is a highly toxic pollutant.It is widely present in the environment and is one of the major heavy metal pollutants.Heavy industry involved in Cd discharges waste water into the air,soil and water,polluting feed raw materials.The contaminated feed is accumulated in various organs of the body after being eaten by livestock and poultry,and is further harmed to human health through the food chain enrichment,resulting in various toxic effects.However,the molecular mechanism of spleen injury caused by Cd exposure is still unclear.In order to clarify the situation of Cd contamination of chicken feed in various regions of Heilongjiang,sample feed of broiler compound feed in various regions was collected.Inductively coupled plasma mass spectrometry was used to detect the cadmium content of broiler compound feed samples.In order to explore the molecular mechanism of feed Cd damage to chicken spleen,establish a Cd exposure model,add different concentrations of Cd to the diet to feed male Hailan white chicken,observe the spleen pathological changes,Detection of heat shock response related factors and anoikis-related factors showed that:(1)The overall over-standard rate of Cd content in the compound feed of broilers measured was 3.1%,and the maximum content of cadmium in feed was 1.49 mg / kg.(2)Cd exposure leads to congestion of the spleen,the border between red and white pulp gradually blurs until disappearance,the thickness of the sheath artery wall increases,the number of lymphocytes decreases,and the number of splenic nodules decreases.It showed that Cd exposure can cause morphological damage to chicken spleen.(3)The detection of genes related to the HSR signaling pathway in chicken spleen tissues revealed that low-dose Cd(?70 mg / kg)can up-regulate heat shock protein genes(HSF1,HSF3,HSP10,HSP25,HSP27,HSP40,HSP47,HSP60,HSP70,HSP90,HSP110)expression,induced heat shock response,high dose Cd(> 70 mg / kg)can significantly down-regulate heat shock protein gene,indicating that the HSR signaling pathway can be activated to resist the damage caused by Cd exposure when exposed to low and medium dose Cd High-dose Cd can inhibit the expression of heat shock protein to play the role of spleen damage,which may be one of the mechanisms of Cd-induced spleen toxicity.(4)Further detection of genes related to anointed apoptosis in chicken spleen cells revealed that the expression of ITGB1 decreased in a dose-dependent manner.At the same time,a reduction in the expression levels of ITGB4 and Fak was also observed.This indicates that integrin-mediated adhesion of cells to the extracellular matrix is impaired.Cd exposure leads to the activation of the characteristic apoptotic molecule Bid,which leads to the activation of Caspase family proteins.Caspase-8 was first activated,and then strengthened the induction of Caspase3,Caspase6,and Caspase7,which eventually led to anoikis,suggesting that the damage of splenic lymphocytes caused by Cd mainly occurred in the form of anoikis.It was shown that Cd exposure had obvious toxic effects on the spleen of chickens,and anoikis was the main way of spleen injury caused by Cd.In summary,The content of cadmium in the compound feed of broilers in some areas of Heilongjiang Province exceeds the standard.Animal experiments show that low-dose Cd exposure activates the HSR signaling pathway and induces the body's anti-injury defense response;high-dose Cd exposure inhibits the HSR signaling pathway,and the ability of heat shock proteins to resist damage is inhibited.Cd exposure can induce splenic cells anoikis,leading to spleen injury.