High Dietary Copper Increases Catecholamine Concentrations in the Hypothalami and Midbrains of Growing Pigs

Effects of Different Concentration of Copper on Performance, Immunity and Carcass Traits in Broiler Japanese Quails

In this study, the effects of dietary copper supplements on broiler Japanese quail growth performance, immune response, blood biochemistry, and carcass quality were examined. Two copper sources (copper sulphate-CuS, and copper methionine-CuM), each at five distinct dietary dosages of 5, 10, 15, 100, and 150 mg/kg, were used. A total of 280 (10 × 4 × 7) day-old quail chicks of uniform body weight were randomly distributed into 10 treatments with 4 replicates each and having 7 chicks in each replicate. In comparison to CuS-supplemented diets, CuM-supplemented diets (100 mg Cu/kg diet) considerably (P ≤ 0.01) increased body weight gain and improved feed conversion ratio (FCR). In the 150-mg CuM/kg diet, the cell-mediated immune response (foot web index to PHAP) was considerably (P ≤ 0.01) greater. The humoral immune response (HA titre to SRBC) was substantially (P ≤ 0.01) lower with CuS-supplemented meals than with CuM-supplemented diets. When compared to CuS source, the weight of the bursa and spleen from CuM source was considerably (P ≤ 0.01) higher. The 100- and 150-mg CuM/kg diets considerably (P ≤ 0.01) reduced serum cholesterol levels. Thus, it may be concluded that dietary supplementation of copper methionine as a source of Cu @ 100 mg Cu/kg diet to broiler Japanese quails was more effective in improving growth performance, immunological response, carcass quality features, and serum cholesterol reduction.

Long-term copper exposure promotes apoptosis and autophagy by inducing oxidative stress in pig testis

Copper (Cu) is a heavy metal which is being used widely in the industry and agriculture. However, the overuse of Cu makes it a common environmental pollutant. In order to investigate the testicular toxicity of Cu, the pigs were divided into three groups and were given Cu at 10 (control), 125, and 250 mg/kg body weight, respectively. The feeding period was 80 days. Serum hormone results showed that Cu exposure decreased the concentrations of follicular stimulating hormone (FSH) and luteinizing hormone (LH) and increased the concentration of thyroxine (T4). Meanwhile, Cu exposure upregulated the expression of Cu transporter mRNA (Slc31a1, ATP7A, and ATP7B) in the testis, leading to increase in testicular Cu and led to spermatogenesis disorder. The Cu exposure led to an increased expression of antioxidant-related mRNA (Gpx4, TRX, HO-1, SOD1, SOD2, SOD3, CAT), along with increase in the MDA concentration in the testis. In LG group, the ROS in the testis was significantly increased. Furthermore, the apoptotic-related mRNA (Caspase3, Caspase8, Caspase9, Bax, Cytc, Bak1, APAF1, p53) and protein (Active Caspase3) and the autophagy-related mRNA (Beclin1, ATG5, LC3, and LC3B) expression increased after Cu exposure. The mitochondrial membrane potential in the testicular tissue decreased, while the number of apoptotic cells increased, as a result of oxidative stress. Overall, our study indicated that the Cu exposure promotes testicular apoptosis and autophagy by mediating oxidative stress, which is considered as the key mechanism causing testicular degeneration as well as dysfunction.

Meta-analysis of the correlation between dietary copper supply and broiler performance

OBJECTIVE

To conduct a meta-analysis assessing the correlation between dietary copper supply and broiler performance.

METHODS

Studies that were published prior to January 2019 and reported the dietary copper supply and broiler growth performance were identified using search functions in the Web of Science, Springer, Elsevier, Science Direct, and Taylor & Francis Online databases; the Journal of Dairy Research; and China National Knowledge Infrastructure (CNKI). We performed stratified analyses on the possible sources of bias, including differences in the study locations and years of publication. The publication bias was assessed with Egger's test method.

RESULTS

A total of 12 randomized controlled trial (RCT) studies were eligible for inclusion. The pooled WMDs of the ADG, ADFI and FCR were -0.166 (95% CI: -1.587 to 1.254), -0.844 (95% CI: -1.536 to -0.152) and -0.029 (95% CI: -0.057 to 0.000), respectively. In the Israeli and Indian studies, the ADG and ADFI data in the experimental group were higher than those in the control group; however, in America, a relatively high FCR value was found in the experimental group compared to that in the control group. The analysis of the study period showed that for the 1980s and 2010s, the ADG and ADFI of the experimental group were lower than those of the control group, while, in the 1990s and 2010s, the FCR of the experimental group were lower than those of the control group. The observed values were adjusted for study effects, and a model was used to obtain the copper supplementation under the optimal production performance. The results showed that the adjusted average daily gain (ADG), average daily feed intake (ADFI), and feed to gain ratio (FCR) presented a quadratic relationship with Cu supplementation (P<0.05). The maximum value of ADG (31.84 g/d) is reached when Cu is added at amount of 158 mg/kg, and the minimum value of FCR (1.53) is reached when Cu is added at amount of 217 mg/kg. No significant publication bias existed in the studies (Egger's test: P value were 0.81, 0.71 and 0.14).

CONCLUSION

From this study, it can be concluded that the traditional copper addition is no longer suitable for modern broiler breeding; the higher copper content may be beneficial for the production performance of broilers.

Effects of copper on oxidative stress and autophagy in hypothalamus of broilers

The purpose of this research was to discuss the effects of copper (Cu)-induced toxicity on oxidative stress and autophagy in hypothalamus of broilers. In this study, 240 one-day-old broilers were randomly divided into 4 groups and the contents of dietary Cu in 4 groups were 11 mg/kg (control group), 110 mg/kg (group I), 220 mg/kg (group II), and 330 mg/kg (group III). The experiment lasted for 49 days and the hypothalamus tissues were collected for histological observation and detection of Cu content. Additionally, the indicators related to oxidative stress in hypothalamus were determined. Moreover, the mRNA expression levels of autophagy-related genes and the protein expression levels of Beclin1, LC3-II/LC3-I, and p62 in hypothalamus were measured. Results showed that the treated groups were observed vacuolar degeneration in hypothalamus compared to control group, and the Cu content in hypothalamus was increased with the increase of dietary Cu. Furthermore, the activities of SOD, CAT, T-AOC were increased in group I and group II and then decreased in group III, and the content of MDA and the mRNA levels of Nrf2, HO-1, SOD-1, CAT, GCLC, GCLM, and GST in treated groups were elevated compared to control group. Moreover, the mRNA expression levels of Beclin1, Atg5, LC3-I, LC3-II and the protein expression levels of Beclin1 and LC3-II/LC3-I up-regulated significantly with the increasing levels of Cu. However, the mRNA expression levels of p62 and mTOR and the protein expression level of p62 down-regulated remarkably. Taken together, our present study evidenced that excessive intake of Cu could induce oxidative stress and autophagy in hypothalamus of broilers.

Copper and the brain noradrenergic system

Copper (Cu) plays an essential role in the development and function of the brain. In humans, genetic disorders of Cu metabolism may cause either severe Cu deficiency (Menkes disease) or excessive Cu accumulation (Wilson disease) in the brain tissue. In either case, the loss of Cu homeostasis results in catecholamine misbalance, abnormal myelination of neurons, loss of normal brain architecture, and a spectrum of neurologic and/or psychiatric manifestations. Several metabolic processes have been identified as particularly sensitive to Cu dis-homeostasis. This review focuses on the role of Cu in noradrenergic neurons and summarizes the current knowledge of mechanisms that maintain Cu homeostasis in these cells. The impact of Cu misbalance on catecholamine metabolism and functioning of noradrenergic system is discussed.