Effects of High-Dose of Copper Amino Acid Complex on Laying Performance, Hematological and Biochemical Parameters, Organ Index, and Histopathology in Laying Hens.

Abstract

The objective of the study was to evaluate the maximum tolerance limit of amino acid copper complex (Cu-Lys-Glu) for laying hens by measuring their laying performance, hematological and serum biochemical parameters, organ index, and histopathology. A total of 450 18-week-old Beijing White layers were randomly allocated to 5 groups (90 birds per group) with 6 replicates of 15 birds each. After a 2-week acclimation on a basal diet (analyzed copper content 8.63mg/kg), the birds were fed diets supplemented with 0 (control), 15, 75, 150, and 300mg Cu/kg as Cu-Lys-Glu for 10weeks. Results showed that, compared with the control group, dietary supplementation with 15, 75, and 150mg Cu/kg as Cu-Lys-Glu did not affect (P > 0.05) laying performance, whereas hens receiving with 300mg Cu/kg significantly decreased (P < 0.001) the laying rate as compared with the control. No significant differences (P > 0.05) were observed among the hens receiving 0, 15, 75, and 150mg Cu/kg as Cu-Lys-Glu in hematological and serum biochemical parameters, organ indexes, and histopathological changes. However, hens receiving 300mg Cu/kg significantly increased (P < 0.05) the concentrations of mean corpuscular volume (MCV), albumin (ALB), total bilirubin (TBILI), alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea nitrogen (UN), and creatinine (CRE), as well as caused severe microscopic histopathological changes in the liver and kidney. In conclusion, 150mg Cu/kg as Cu-Lys-Glu is identified as no-side-effect supplementation level in laying hens after daily administration for 70days.