Cr (chromium, with common valence states of III and VI) is one of the common broiler feed additives. Liver injury and metabolic disorders could be caused by Cr(VI) (hexavalent chromium) poisoning in broilers. Oxidative damage and metabolic disorders of organisms caused by heavy metals could be antagonized by nano-Se (nano-selenium). Nano-Se was chosen to study the antagonism of Cr(VI) poisoning in broilers. AMPK (Adenosine 5,-monophosphate-activated protein kinase) is known as a "cell energy regulator" and plays a key regulatory role in carbohydrate and lipid metabolism. AMPK pathway and ACACA/CPT1A two genes were selected to study the prevention and treatment of nano-Se on Cr(VI) poisoning in broilers and its molecular mechanism. For this purpose, 180 1-day-old AA (Arbor Acres) broilers were selected and randomly divided into 6 groups (n = 30) for further testing. After feeding as planned for 35 days, the livers of such broilers were taken for further examination including histopathological examination, differential gene expression analysis, and further validation on both mRNA and protein levels using related techniques like RT-qPCR, western blot, and immunohistochemistry (IHC). The histopathological examination suggested that the liver cells of the Cr(VI) poisoning group were more severely injured than the nano-Se addition group. RT-qPCR results showed that the relative expression of ACACA gene in the Cr(VI) poisoning group was significantly increased (P < 0.05), while the CPT1A gene's expression was significantly decreased (P < 0.01). Those results were reversed in the nano-Se addition group. Western blot results were consistent with RT-qPCR and both suggested antagonism of nano-Se on Cr(VI). Through morphological and histopathological observation, as well as the measurement of the mRNA and protein expression levels of ACACA and CPT1A genes in AMPK pathway, it was confirmed that nano-Se has certain preventive and protective effects on Cr(VI) poisoning in broiler chickens. Furthermore, the adverse effects of Cr(VI) on carbohydrate and lipid metabolism in broilers can be antagonized by nano-Se through AMPK pathway. A new method and experimental basis were provided to the future study of Cr(VI) poisoning in broilers.
Keywords: AA broilersArbor Acres broilers; ACACA gene; ACACAAcetyl CoA carboxylase; AMPK pathway; AMPKAdenosine 5,-monophosphate-activated protein kinase; Abbreviations; CPT1A gene; CPT1ACarnitine palmitoyl transferase 1 A; Cr (III)Trivalent chromium; Cr (VI)Hexavalent chromium; Cr(VI) poisoning; CrChromium; GTFGlucose tolerance factor; High-throughput sequencing; K2Cr2O7Potassium dichromate; LD50Median lethal dose; Nano-SeNano-selenium; Nano-selenium; PSEPale soft exudative meat.