Effect of the use of golden mussel flour contaminated with lead as a source of calcium on the performance of broilers

Abstract

The objective of this study was to evaluate the use of lead contaminated golden mussel flour (GMF) as a source of calcium for broiler chickens from 14 to 42 days of age and to verify the probable effects on performance, tissue contamination, blood parameters, Pb digestibility, and bone quality. The experiment was conducted in a completely randomized design (DIC), with four levels of Pb contamination (71.33, 147.55, 223.78, and 300 mg kg^-1 Pb) in GMF, with five replicates and three birds per experimental unit. Sixty-four-day-old Cobb male broilers housed in metabolism cages were used. GMF was added to rations instead of calcitic limestone. The zootechnical variables were evaluated: feed intake, weight gain, and feed conversion, as well as the digestibility of nutrients. In addition, the serum biochemistry of the birds transaminases, total bilirubin, calcium, and phosphate was studied and the concentration of lead in the tissues and the bone quality of the birds was determined. The tibia was collected for evaluation of bone quality. The levels of Pb contamination in the golden mussel did not change the performance of the birds (P ? 0.05) or the Pb levels in the muscle Pectoralis major, skin, liver, feather, bones, and serum, or the serum levels of ALT, GGT, and total bilirubin, however, there was an effect of Pb levels (P < 0.01) on AST concentrations. Pb levels altered the values (P < 0.01) of the apparent digestible Pb and the coefficient of apparent digestibility of Pb, with an increasing linear effect. There was no effect (P ? 0.05) on bone stiffness, however flexibility and bone strength were altered (P < 0.05). Serum Ca and P concentrations did not show changes (P ? 0.05) due to the use of Pb levels in GMF. In this study, it can be observed that the use of GMF with Pb up to 300 mg kg^-1 as a source of Ca in broiler diets does not alter performance, however the use of GMF contaminated with Pb above 73.33 mg kg^-1 promotes contamination of the tissues of the animals with Pb, making it impossible to consume the birds. It was concluded that the increase in Pb concentrations in GMF increases the digestibility and metabolism of this metal and causes an increase in the production of AST by the liver. Pb levels in GMF above 214.11 mg kg^-1 impair bone strength and flexibility.