Avaliação de fontes de cobre para ovinos com ensaio de biodisponibilidade

Abstract

The study was conducted to estimate the relative bioavailability of two sources of supplemental copper: organic (copper methionine) and inorganic (copper sulfate) in the diet of lambs, by analyzing the concentration of copper and enzymes in the liver and metabolic balance calculation, using 40 lambs breed Merino X Texel, which was fed three concentrations of copper (basal + two additions) in two sources, which were randomly allotted to five groups, and subjected to five treatments: treatment 0: control (diet without addition of Cu); treatment 1: (diet with 10 mg Cu/Kg DM of CuSO 4) ; Treatment 2: (diet with 30 g Cu/Kg DM of CuSO 4); Treatment 3: (diet with 10 mg Cu/kg DM of copper methionine; Treatment 4: (diet with 30 mg cu/kg DM of copper methionine). Liver biopsies were made on 0 d. Blood samples were taken via the jugular vein on 0, 28, 56 and 84 d to determine serum Cu and serum ceruloplasmin and liver transaminases (AST, ALT) concentrations. The animals were slaughtered and samples of liver, kidney and muscle were taken for the determination of the levels of Cu and superoxide dismutase activity. In the last ten days of the experiment a metabolic balance of copper was conducted. The bioavailability was calculated by the "slope ratio" technique, using the concentration of copper in the liver as parameter. There was no difference (P >0.05) on animal performance (live weight and weight gain) among treatments. The serum AST and ALT levels remained below poisoning in all treatments during the period. The ceruloplasmin activity did not differ between treatments (P>0.05). The copper content in biopsy, serum and muscle was not different (P>0.05) between treatments. However, the mineral concentration in the liver of animals fed (284.28 mg/kg) was higher (P <0.05) when compared to the control group (168.01 mg/kg) and 30 Cumet mg/kg (341.29 mg/kg) was higher (P <0.05) at 10mg/kg MS (263.02 mg/kg). The SOD activity in the supplemented animals (mmol/mg prot) was superior to the control group. Copper in Kidneys was higher in animals that received 30mg/kg MS meth-Cu (6.65mg/kg) compared those receiving 10 mg/kg DM from the same source (3.86 mg/kg). Apparent absorption and retention of copper were higher for inorganic source, compared with the organic. The bioavailability determined by the concentration of copper in the copper liver, using the technique of "slope ratio", considering CuSO4 as standard (100%) presented availability of 150.64 % for Cumet.

Efeitos de fontes orgânicas de cobre e enxofre sobre a interação cobre, molibdênio e enxofre na alimentação de ovinos

“…Em estudos de biodisponibilidade em ovinos comparando sulfato de cobre e cobre metionina, através da estimativa pela regressão múltipla slope ratio, Yoshikawa (2014) …”