Effects of different sources and levels of copper on growth performance, nutrient digestibility, and elemental balance in young female mink (Mustela vison)

Long-term copper exposure caused hepatocytes autophagy in broiler via miR-455-3p-OXSR1 axis

Copper (Cu) is a common environmental pollutant which has been identified to cause toxic effects on animal bodies. MicroRNAs (miRNAs) are a type of non-coding RNAs involved in the regulation of various cellular activities including autophagy, but the potential regulatory mechanisms after excess Cu intake are still uncertain. Our previous study has prompted that Cu exposure reduced liver miR-455-3p levels. Herein, miR-455-3p was found to be an important molecule in the regulation of Cu-induced autophagy in vivo and in vitro. Histopathology observation of liver tissue indicated that Cu-induced severe hepatic damage including cellular swelling and vacuolization. Meanwhile, excessive Cu exposure not only heighten the mRNA and protein expression levels of Beclin1, Atg5, LC3Ⅰ and LC3Ⅱ, but also decreased miR-455-3p levels. In vitro experiment, Cu-induced autophagy can be attenuated by miR-455-3p overexpression. Additionally, oxidative stress-responsive 1 (OXSR1) was identified as a direct downstream target of miR-455-3p by dual luciferase reporter assays. Moreover, knockdown of OXSR1 can attenuate the autophagy induced by Cu treatment and the miR-455-3p inhibitor. Overall, the miR-455-3p-OXSR1 axis works as a regulator of autophagy under Cu stress, which provides a basis for further revealing the mechanism of chronic Cu poisoning.

Preparation and process optimization of microbial organic copper as a feed additive

ABSTRACT As an essential trace element for animals, copper significantly contributes to the growth and health of animals. Compared to inorganic trace elements, organic trace elements are better supplements; notably, they are acquired through microbial transformation. Therefore, we screened for copper-enriched microorganisms from high copper content soil to obtain organic copper. Sodium diethyldithio carbamate trihydrate was applied as a chromogenic agent for determining micro amounts of intracellular copper through spectrophotometry. In total, 50 fungi were isolated after the successful application of the screening platform for copper-rich microbes. Following morphological and molecular biology analyses, the N-2 strain, identified as Aspergillus niger sp. demonstrated showed better copper enrichment potential than others. Notably, the strain tolerance to copper was nearly thrice that of Saccharomyces cerevisiae, up to 1600mg/L. The content of the organic bound copper was 22.84mg Cu/g dry cell. Using the Central Composite Design (CCD) response surface method, we optimized the fermentation condition (inoculation amount, 13%; temperature, 28(C; pH, 5.0). Compared to the original strain results under the single factor fermentation condition, we reported an increase by 24.18% under the optimized conditions. Collectively, these findings provide a reference for uncovering new and low-cost organic copper additives.

Effects of Copper Sources and Levels on Lipid Profiles, Immune Parameters, Antioxidant Defenses, and Trace Element Residues in Broilers

The study was conducted to investigate the effects of copper sources and levels on lipid profiles, immune parameters, antioxidant defenses, and trace element contents of meat and liver in Arbor Acres broilers. A total of 504 male broilers were randomly divided into 7 groups with 6 replicates per group and 12 broilers per replicate. The experiment was used in a 3 × 2 + 1 factorial experiment design; broilers in the control group were fed a basal diet, and broilers in the other six groups were fed basal diets supplemented with 3 sources (copper sulfate, tribasic copper chloride, and copper methionate) and 2 levels (10 and 20 mg/kg). The results showed that the levels of cholesterol and low-density lipoprotein cholesterol in broilers were significantly decreased with the increase of dietary copper level (P < 0.05). Serum IL-6 and IgA contents, ceruloplasmin and GSH-Px activities, and liver copper contents of broilers increased significantly with dietary copper levels (P < 0.05). Compared with the control group, dietary copper supplementation significantly decreased serum cholesterol (P < 0.05) and significantly increased serum IL-6, ceruloplasmin, SOD, GSH-Px, and liver copper (P < 0.05). Dietary supplementation of basic copper chloride and copper methionate significantly decreased low-density lipoprotein cholesterol content and liver iron content (P < 0.05). In conclusion, dietary copper supplementation can effectively reduce serum cholesterol content and improve immune and antioxidant functions in broilers. Adding 20 mg/kg copper to broiler diet can increase the copper content in the liver, but it will not affect the copper content in the chicken.

Effects of sources and concentrations of zinc on growth performance, nutrient digestibility, and fur quality of growing-furring female mink (Mustela vison)

A completely randomized 3 × 3 + 1 factorial experiment was conducted to evaluate the effects of sources and concentrations of Zn on growth performance, nutrient digestibility, serum biochemical endpoints, and fur quality in growing-furring female black mink. One hundred fifty healthy 15-wk-old female mink were randomly allocated to 10 dietary treatments ( = 15/group) for a 60-d trial. Animals in the control group were fed a basal diet, which consisted of mainly corn, soybean oil, meat and bone meal, and fish meal, with no Zn supplementation. Mink in the other 9 treatments were fed the basal diet supplemented with Zn from either zinc sulfate (ZnSO), zinc glycinate (ZnGly), or Zn pectin oligosaccharides (ZnPOS) at concentrations of either 100, 300, or 900 mg Zn/kg DM. The results showed that mink in the ZnPOS groups had higher ADG than those in the ZnSO groups (main effect, < 0.05). The addition of Zn reduced the G:F ( < 0.05). In addition, CP and crude fat digestibility were linearly increased with Zn supplementation ( < 0.05) and N retention tended to increase with Zn addition ( = 0.08). Dietary Zn supplementation increased the concentration of serum albumin and activity of alkaline phosphatase ( < 0.05). There was a linear effect of dietary Zn on the concentration of tibia Zn and pancreatic Zn ( < 0.05). For fur quality characteristics, the fur density and hair color of mink were improved by dietary Zn concentration ( < 0.05). Compared with ZnSO (100%), relative bioavailability values of ZnGly were 115 and 118%, based on tibia and pancreatic Zn, respectively, and relative bioavailability values of ZnPOS were 152 and 142%, respectively. In conclusion, this study demonstrates that Zn supplementation can promote growth and increase nutrient digestibility and fur quality and that ZnPOS is more bioavailable than ZnSO and ZnGly in growing-furring female mink.

Influence of dietary zinc and copper on apparent mineral retention and serum biochemical indicators in young male mink (Mustela vison)

An experiment was conducted in a 3 × 3 (Cu × Zn) factorial experiment based on a completely randomized design to evaluate the effects of dietary copper and zinc on apparent mineral retention and serum biochemical indicators in young male mink on a corn-fish meal based diet. Animals were fed basal diets supplemented with Cu from copper sulfate (CuSO4) and Zn from zinc sulfate (ZnSO4). Supplemental Cu levels were 0, 15, and 30 mg/kg copper, respectively, while supplemental Zn levels were 0, 150, and 300 mg/kg, respectively. A metabolism trial of 4 days was conducted during the last week of experimental feeding. Blood samples were collected via the toe clip to determine blood hematology and blood metabolites. Copper excretion, retention, and digestibility were influenced by dietary copper (P < 0.05), however, there was also a zinc-copper interaction. Copper digestibility and retention were substantially reduced when zinc was added to the low copper diet but showed little change with zinc supplementation of the high copper diet. Both plasma Cu and plasma Zn were influenced by dietary level of the respective mineral (P < 0.05). There was no influence of dietary copper on plasma zinc; however, high Zn in the diet reduced plasma Cu concentrations. There was a zinc-copper interaction for plasma Cu (P = 0.053). Cu-Zn superoxide dismutase (Cu-Zn SOD) activity tended to be influenced by dietary zinc (P = 0.065) and dietary copper (P = 0.035). Dietary copper had a significant effect on ceruloplasmin (CER) and triglyceride (TG) concentrations (P < 0.05). Our results show that moderately high Zn in the diet (Zn:Cu ratio of 40:1) significantly reduce the apparent Cu digestibility. Our results also show that moderately high Cu in the diet increases Cu retention, but not reduces Zn absorption, and moderately high Zn in the diet reduced plasma Cu concentrations and CER activity.