Technical note CONCENTRATION OF COPPER IN MUSCLES, LIVER, HAIR AND FAECES OF GROWING RABBITS FED DIET SUPPLEMENTED WITH COPPER SULPHATE

Abstract

[EN] The supplementation of diets for rabbits with copper has been restricted in the EU to 35 mg/kg. In our experiment, quadruple concentration of Cu added to a pelleted diet as CuS04.5H,0 was used to investigate effect of Cu feeding on Cu concentration in muscles, liver, ha ir and faeces of Hyplus® rabbits. The main ingredients of the basal diet were alfalfa meal, wheat bran, sunflower meal, oat, barley, sugarbeet pulp and soyabean mea l. Six rabbits, 35 days of age at the beginning of the experiment, were fed basal diet (containing 1 O mg Cu/kg), and six rabbits were fed Cu-supplemented diet. Cu concentration in faeces was measured weekly. Rabbits were slaughtered at the age of 87 days. Cu concentrations in muscles, liver, hair and faeces were assayed by the atomic absorption spectrometry. The highest concentration of Cu was found in liver of Cu-fed rabbits: 118.5 ± 31.8 mg/kg (4.6 ± 0.5 mg/kg in controls). The Cu concentration in meat of Cu-fed rabbits was very low: 0.48 ± 0.05 and 0.37 ± 0.04 in hindleg and loin, respectively. Corresponding Cu concentrations in control rabbits were 0.48 ± 0.05 and 0.35 ± 0.04 mg/kg. Hair of Cu-fed and control rabbits contained 9.55 ± 0.46 and 9.14 ± 1.05 mg Cu/ kg, respectively. On average, faeces of Cu-fed and control rabbits contained 273 and 15.3 mg Cu/kg, respectively. Faecal excretion is thus probably the main route of Cu output in Cu-fed rabbits. On the basis of our results, we conclude that Cu-fed rabbits accumulated Cu in the liver. No substantial Cu retention in the meat of Cu-fed supplemented rabbits was observed.