Glycogen, proteins, and aminotransferase (GOT, GPT) changes in the frog Rana ridibunda exposed to high concentrations of copper

Hepatic metallothioneins in molecular responses to cobalt, zinc, and their nanoscale polymeric composites in frog Rana ridibunda

Despite numerous studies suggesting a dramatic decline of amphibians, the biochemical mechanisms of adaptation in these animals to polluted environment are poorly studied. The aim of this study was to elucidate the ability to release cobalt (Co) and zinc (Zn) from their nanoscale complexes (NCs) derived from the polymeric substance of N-vinylpyrrolidone (PS) in the liver of amphibian (Rana ridibunda). Frog males were subjected to 14days exposure to waterborne Co(2+) (50μg/L), Zn(2+) (100μg/L), as well as corresponding concentrations of Co-NC, Zn-NC or PS. Main attention was paid to MT's interrelations with indices of stress and toxicity. Only Co(2+) and Zn(2+) caused elevation of the correspondent metal in MTs. Co(2+) caused down-regulation of cathepsin D activity, while Zn(2+), Zn-NC and the PS up-regulated this activity. Zn(2+) provoked 1.6 times increase of metal-bounded form of the MT (MT-Me), while all other exposures caused the elevation of the ratio of MT total protein concentration (MT-SH) and concentrations of the MT-Me and/or immunoreactive (MTi) form (up to ~10 times) accompanied by a decrease in the levels of oxyradicals. The increased DNA fragmentation and down-regulation of caspase-3 activity in relation to the redox state of glutathione and/or lactate/pyruvate were shown at all exposures. These data indicate the vulnerability of the redox state of cellular thiols and inability to release Co and Zn from NCs in frog's liver.

Effects of dietary copper on elemental balance, plasma minerals and serum biochemical parameters of growing-furring male mink (Mustela vison)

The objectives of this study were to study the effects of different levels of dietary copper on copper and zinc balance, plasma minerals and serum biochemical parameters of mink in the growing-furring periods. One hundred and five standard dark male mink were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (Control); basal diet supplemented with either 6, 12, 24, 48, 96, or 192 mg/kg Cu from copper sulfate, respectively. The average daily gain (ADG) linearly (P = 0.0026, P = 0.0006) responded to increasing levels of Cu; maximal growth was seen in the Cu24 group. Feed efficiency tended to improve with the increase of dietary copper level (linear P = 0.0010, quad, P = 0.0011). Fecal copper, urinary copper, retention copper responded in a linear (P < 0.05) fashion with increasing level of Cu. The effect of level of Cu was linear (P < 0.001) for plasma Cu concentration. The serum glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities were increased linearly (P < 0.05) with dose of Cu, but serum total protein (TP) and albumin (ALB) concentrations decreased linearly (P < 0.05) as dietary copper levels increased. Effect of level of Cu was linear (P < 0.001) for serum ceruloplasmin (CER) concentration or Cu-Zn superoxide dismutase (Cu-Zn SOD) activity. Supplemental dose of Cu linearly decreased serum triglyceride (TG) (P = 0.011) and total cholesterol (TC) (P = 0.007). Our results indicated that the activity of Cu-dependent enzymes was enhanced by increasing dietary Cu concentration and that supplementation of Cu in the diet of mink could alter the plasma lipid profile and copper concentration.

Effects of dietary copper on nutrient digestibility, tissular copper deposition and fur quality of growing-furring mink (Mustela vison)

The present study investigated the effects of dietary copper (Cu) on growth performance and fur quality in growing-furring minks. One hundred and five standard dark female minks were randomly assigned to seven groups with the following dietary treatments: basal diet with no supplemental Cu (control) and basal diet supplemented with either 6, 12, 24, 48, 96 or 192 mg/kg Cu from copper sulphate, respectively. Our data showed that final body weight (P = 0.033), daily gain (P = 0.029) and fat digestibility (P = 0.0006) responded to increasing levels of Cu. The activity of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in serum increased (linear and quadratic, P < 0.05) as Cu increased in the diet. Increasing Cu improved total protein (TP) and albumin (ALB) (quadratic, P < 0.05). The level of ceruloplasmin (CER) responded in a linear (P < 0.0001) and quadratic (P < 0.0001) form with increasing level of Cu. Colour intensity of those minks pelted suggested that relatively high levels of supplemental Cu have a beneficial effect on intensifying hair colour of dark mink but did not affect leather thickness. Liver Cu and plasma Cu concentrations of the mink linearly (P < 0.0001) responded to increasing levels of Cu. Our results indicate that growing-furring mink can efficiently utilize added dietary fat and that Cu plays an important role in the digestion of dietary fat in growing-furring mink, and supplemental dietary Cu in growing-furring mink promotes fat digestion and improve hair colour.