Teores de cobre e seus principais antagonistas em fígado e sangue de ovinos e caprinos criados no estado de Pernambuco

Abstract

The aim of this research was to know serum and liver concentrations of Cu, Mo, Fe and Zn in sheep and goats slaughtered in the semiarid region of the state of Pernambuco, Northeastern Brazil, during the rainy and dry seasons, and to determine if Cu deficiency that occurs in the region is primary or secondary to high levels of Mo and/or Fe. Serum and liver samples from 141 goats and 141 sheep were submitted to wet digestion in nitric-percloric acid and analyzed by coupled plasma atomic absorption spectrophotometry. The mean concentration of serum Cu in sheep was 9.22±2.34 μmol/L in the dry period and 10.03±2.89 μmol/L in the rainy period, but females had significantly higher values (10.92±2.56 μmol/L) than males (9.42±2.67 μmol/L). Mean Cu concentrations in the liver were 185.1±88.28 mg per kg of dry matter (mg/kg) in the dry period and 137.95±87.04 mg/kg in the rainy period, and females had significantly higher concentrations (218.61±93.49 mg/kg) than males (133.45±92.37 mg/kg). In goats serum concentrations of Cu were of 11.74±2.36 μmol/L in the dry period and 11.05±2.74 μmol/L in the rainy period, and females (12.10±2.67 μmol/L) had higher concentrations than males (10.14±1.80 μmol/L). Liver concentrations were 155.2±93.40 mg/kg in the dry period and of 149.37±62.33 mg/kg in the rainy period. Mean serum concentrations of Cu in sheep (9.85±2.71 μmol/L) were significantlyt lower than in goats (11.37±2.57 μmol/L), but there were no differences in liver concentrations of Cu between sheep (158.45±83.05 mg/kg) and goats (152.46±79.58 mg/kg). Based in Cu serum and liver concentrations, and in the sporadic occurrence of enzootic ataxia, Cu suplementation is recommended in grazing sheep and goats during the dry and the rainy seasons. In sheep, serum concentrations of Fe were 36.99±15 μmol/L in the dry season and 34.52±14.86 μmol/L in the rainy season, with significant differences between females (29.92±11.06 μmol/L) and males (37.85±15.68 μmol/L). Liver Fe concentrations were significantly lower in the dry season (186.20±30.02 mg/kg) than in the rainy season (229.25±83.15 mg/kg), with no differences between females and males. In goats, serum concentrations of Fe were 25.61±9.35 μmol/L in the dry season and 24.57±6.96 μmol/L in the rainy season, and liver concentrations were of 170.52±56.91 mg/kg in the dry season and 139.73±51.30 mg/kg in the rainy season; there were no significant differences between females and males. Serum levels of Fe were significantly higher in sheep (35.58±14.89 μmol/L) than in goats (25.06±8.10 μmol/L). Also Fe concentrations of the liver were higher in sheep (210.53±121.99 mg/kg) than in goats (156.1±55.99 mg/kg). Considering that serum and hepatic concentrations of Fe are between normal ranges or marginal it is suggested that the low Cu concentrations are not related with high Fe ingestion. In sheep serum concentrations of Mo were 0.33±0.18 μmol/L in the dry season and 0.3±0.15 μmol/L in the rainy season and liver concentrations were 8.27±3.97 in the dry season and 7.96±4.07 in the rainy season. In goats, serum concentrations of Mo were 0.31±0.12 μmol/L in the dry season and 0.26±0.10 μmol/L in the rainy season, and liver concentrations were 7.17±4.09 mg/kg in the dry season and 5.8±4.14 mg/kg in the rainy season. There were no significant differences in serum and liver Mo concentrations between sheep and goats and between males and females. Despite the variations found in this study and also in reference values, it is suggested that the low or marginal Cu concentrations are not due to high Mo intake. In sheep serum concentrations of Zn were significantly lower during the dry season (9.79±3.02 μmol/L) than in the rainy season (13.48±7.22 μmol/L). Also Zn concentrations in the liver were significantly lower in the dry season (109.96±30.23 mg/kg) than in rainy season (139.1±60.45 mg/kg). In goats, serum Zn concentrations were 12.01±9.61 μmol/L in the dry season and 11.6±4.93 μmol/L in the rainy season, and liver concentrations were 134.2±26.58 mg/kg in the dry season and 131.45±76.55 mg/kg in the rainy season. There were no significant differences between serum and liver concentrations of Zn between sheep and goats or between males and females. Taking into account that serum and liver Zn concentrations in sheep and goats are considered marginal, supplementation with this mineral it suggested in grazing sheep and goats, mainly during the dry season.