Sources and levels of copper affect liver copper profile, intestinal morphology and cecal microbiota population of broiler chickens fed wheat-soybean meal diets

Long-term Cu exposure alters CYP450s activity and induces jejunum injury and apoptosis in broilers

Copper (Cu) is an essential trace element that plays a crucial role in numerous physiopathological processes related to human and animal health. In the poultry industry, Cu is used to promote growth as a feed supplement, but excessive use can lead to toxicity on animals. Cytochrome P450 enzymes (CYP450s) are a superfamily of proteins that require heme as a cofactor and are essential for the metabolism of xenobiotic compounds. The purpose of this study was to explore the influence of exposure to Cu on CYP450s activity and apoptosis in the jejunum of broilers. Hence, we first simulated the Cu exposure model by feeding chickens diets containing different amounts of Cu. In the present study, histopathological observations have revealed morphological damage to the jejunum. The expression levels of genes and proteins of intestinal barrier markers were prominently downregulated. While the mRNA expression level of the gene associated with CYP450s was significantly increased. Additionally, apoptosis-related genes and proteins (Bak1, Bax, Caspase-9, Caspase-3, and CytC) were also significantly augmented by excessive Cu, while simultaneously decreasing the expression of Bcl-2. It can be concluded that long-term Cu exposure affects CYP450s activity, disrupts intestinal barrier function, and causes apoptosis in broilers that ultimately leads to jejunum damage.

Effects of copper nanoparticles on performance, muscle and bone characteristics and serum metabolites in broilers

Abstract Three hundred and twenty day old Hubbard broilers were randomly allocated to four treatments (8 replicates, 10 birds/pen) and were raised under standard management conditions. Birds in the first group served as control and were fed a corn based diet, while birds in the remaining three groups i.e.; A, B and C were fed with a basal diet supplemented with copper nanoparticles (CuNP) at 5, 10 and 15 mg /kg of diet respectively for 35 days. Supplementation of CuNP linearly increased (P≤0.05) body weight (BW), average daily weight gain (ADWG) and feed intake (FI) in broilers. Uric acid, glucose levels in blood and feed conversion ratio (FCR) reduced linearly (P≤0.05) with CuNP supplementation in diet. Supplementation of CuNP in the diet also linearly increased (P≤0.05) tibia weight, length, diameter, weight/length index (W/L) and Tibiotarsal index (TT index). Inclusion of CuNP in broilers diet linearly increased the measured parameters of muscle i.e.; pH, fiber diameter, fiber cross-sectional area, fascicle diameter, fascicle cross-sectional area (P≤0.05). Concentration of copper, iron, calcium and phosphorous in blood also increased line-arly (P ≤ 0.05) with CuNP supplementation. Overall, CuNP positively affected the growth performance, histological characteristics of muscles, bone strength and serum metabolites in broilers.

Effect of Copper Exposure on the Cholesterol Metabolism in Broiler Liver

Copper (Cu) is a kind of widely used dietary supplement in poultry production, and a common environmental pollutant at the same time. Excess Cu exposure has been reported to accumulate in the liver and induce cytotoxicity, but the effect of Cu toxicity on hepatic cholesterol metabolism is still uncertain. Herein, we aimed to reveal the effect of excess Cu on the liver and primary hepatocytes of broilers at various concentrations. We found that 110 mg/kg Cu supplement remarkably increased blood cholesterol levels by detecting serum TC, LDL-C, and HDL-C in the broilers, while there was no significant difference in 220 and 330 mg/kg Cu supplements. In addition, high Cu exposure resulted in severe hepatic steatosis and hepatic cord derangement in the broilers. Oil red O staining of primary hepatocytes showed that Cu treatment caused intracellular neutral lipid accumulation. However, the hepatic TC content indicated a downward trend in both liver tissues and hepatocytes after Cu exposure. Furthermore, the expression of cholesterol metabolism-related indicators (SREBP2, HMGCR, LDLR, and CYP7A1) was notably decreased in the Cu-treated groups. While the expression of the key enzyme of cholesterol esterification (ACAT2) did not change significantly. Taken together, our findings preliminarily revealed excess Cu-induced hepatic cholesterol metabolism dysfunction, providing a deeper understanding of the molecular mechanisms of Cu-induced hepatotoxicity.

Copper Super-Dosing Improves Performance of Heat-Stressed Broiler Chickens through Modulation of Expression of Proinflammatory Cytokine Genes

Continuous exposure to high ambient temperatures brings about a number of oxidative damages in chickens. Copper (Cu), an active component of a number of antioxidative defence components, should arrest these changes to take place although that may not be possible under the standard dosing regimen followed by the industry. To ascertain the optimum dose response that may be beneficial in sustaining the performance of chickens under heat stress (HS), broiler chickens (n = 400) were exposed to high ambient temperature (between 27.2°C and 35.3°C) during 1-35 d. Copper (Cu) as Cu proteinate (Cu-P) at concentrations of 37.5, 75, 112.5, and 150 mg/kg was supplemented to the diet. The negative control (NC) diet did not contain any supplemental Cu. Increasing dietary Cu improved (P < 0.001) body weight, feed intake, and conversion ratio. Serum concentrations of total cholesterol at 21 d (P = 0.009), HDL cholesterol at 35 d (P = 0.008), LDL cholesterol at 21 d (P = 0.015), and triacylglycerol at both 21 d (P = 0.033) and 35 d (P = 0.001) decreased as Cu in the diet increased. As Cu in the diet increased, hemoglobin increased (P = 0.003) at 21 d, and the heterophil to lymphocyte ratio decreased both at 21 d (P = 0.047) and 35 d (P = 0.001). Superoxide dismutase and glutathione peroxidase activities increased when dietary Cu increased to 150 mg/kg (P < 0.01). Liver Cu at 35 d increased linearly with the dose of Cu in the diet (P = 0.0001). Selected bacteria were enumerated in the digesta to ascertain if Cu super-dosing affected their population in any way in the absence of any enteric challenge. Escherichia coli and total Salmonella numbers decreased (P = 0.0001), and total Lactobacillus increased (P = 0.0001) proportionately with dietary Cu. Interleukin-6 and tumour necrosis factor-α gene expression increased linearly (P = 0.0001) as Cu in the diet increased though the response plateaued at 112.5 mg/kg. It was concluded from the present experiment that during conditions of impending HS, dietary supplementation of 112.5 to 150 mg Cu/kg diet as Cu-P may be a novel strategy to alleviate the negative effects of HS without involving any apparent risk of Cu toxicity.

Dietary phytase effects on copper requirements of broilers

Information on the availability of Cu from plant feedstuffs for broilers in the presence of phytase is scarce. The present research has been conducted with the objective of evaluating the Cu requirements of broilers when fed corn-soy diets with or without phytase. A total of 640 one-day-old male Cobb x Cobb 500, allocated into 80 battery cages with 8 chicks in each, were fed a low Cu content diet (formulated with 8.58 ± 0.21 mg/kg Cu) without phytase from placement to day 7. Starting on day 8, battery cages were distributed into a 2 × 5 factorial arrangement (phytase-added diets X 5 with graded increases of supplemental Cu) until day 28. Feeding treatments (feeds added or not with phytase and 5 graded increases of Cu) were randomly distributed with 8 cages of 8 chicks. The basal non-supplemented feeds were formulated with corn and soybean meal (SBM) without any other significant Cu contributors. Supplemental Cu was from laboratory-grade Cu sulfate pentahydrate (CuSO5H20) which was increasingly added to the feeds. Phytase was added in excess to the producer recommendation (2,500 FYT) and had average analyzed values of 2,768 ± 135.2 FYT/kg whereas analyzed Cu values were: 8.05 ± 0.25, 11.25 ± 0.15, 14.20 ± 0.40, 16.55 ± 0.05, and 19.45 ± 0.45 mg/kg. Statistics were conducted using linear and quadratic polynomial regression models. No interactions occurred between dietary Cu and phytase (p > 0.05) for any response and no effects were found for the individual factors (phytase or dietary Cu) for Ht, Hb, varus, valgus, rotated tibia, and tibia breaking strength, as well as for Cu contents in breast, gastrocnemius tendon, and kidney (p > 0.05). However, the phytase-added diets led to higher BWG, lower FCR, and increased ileal digestible Cu (p < 0.05). The gradual increase in dietary Cu produced linear increases in Cu content in livers, as well as in excreta and retention (p < 0.05). Supplementing phytase at levels expected to maximize phytate degradation was demonstrated to improve BWG and FCR; however, no effects were observed when dietary Cu was increased to a maximum of 19.45 mg/kg. An increase of 8.8% in ileal digestible Cu was observed when birds were fed phytase.

Effects of bis-chelated copper in growth performance and gut health in broiler chickens subject to coccidiosis vaccination or coccidia challenge

Copper (Cu) is widely used at high levels as growth promoter in poultry, the alternative source of Cu to replace the high level of inorganic Cu at poultry farm remains to be determined. Three floor pen experiments were conducted to evaluate the effects of Cu methionine hydroxy-analogue chelate (Cu-MHAC, MINTREX^®Cu, Novus International, Inc.) on growth performance and gut health in broilers in comparison to CuSO₄ and/or tribasic copper chloride (TBCC). There were 3 treatments in experiment#1 (0, 30 and 75 ppm Cu-MHAC) and experiment#2 (15 and 30 ppm Cu-MHAC, and 125 ppm CuSO₄), and 4 treatments in experiment #3 (15 and 30 ppm Cu-MHAC, 125 ppm CuSO₄ and 125 ppm TBCC) with nine replicates pens of 10-13 birds in each treatment. The levels of other minerals were equal among all treatments within each experiment. All birds were orally gavaged with a coccidiosis vaccine at 1x recommended dose on d0 in experiment#1 and #2 and 10x recommended dose on d15 in experiment #3. Data were analyzed by one-way ANOVA, means were separated by Fisher's protected LSD test. A p ≤ 0.05 was considered statistically different. In experiment #1, 30 and 75 ppm Cu-MHAC improved FCR during grower phase, increased jejunal villus height and reduced jejunal crypt depth, 30 ppm Cu-MHAC increased cecal Lactobacillus spp. abundance in 41 days broilers. In experiment #2, compared to CuSO₄, 15ppm Cu-MHAC increased cumulative performance index in 28 days broilers, 15 and/or 30 ppm Cu-MHAC improved gut morphometry, and 30 ppm Cu-MHAC reduced the abundance of E. coli and Enterobacteriaceae in cecum in 43 days broilers. In experiment #3, 15 ppm and 30 ppm Cu-MHAC improved FCR vs. CuSO₄ during starter phase, reduced the percentage of E. coli of total bacteria vs. TBCC, 30 ppm Cu-MHAC increased the percentages of Lactobacillus acidophilus, Lactobacillus spp. and Clostridium cluster XIVa of total bacteria vs. both CuSO₄ and TBCC in the cecum of 27 days broilers. In summary, low doses of Cu-MHAC had comparable growth performance to high dose of TBCC and CuSO₄ while improving gut microflora and gut morphometry in broilers subject to coccidiosis vaccination or coccidia challenge, indicating that low doses of bis-chelated Cu could be used as a complimentary strategy to improve animal gut health.

MitomiR-504 alleviates the copper-induced mitochondria-mediated apoptosis by suppressing Bak1 expression in porcine jejunal epithelial cells

Copper (Cu), an environmental heavy metal pollutant, has been widely researched in its toxicology. Recently, an increasing number of mitochondrial microRNAs (mitomiRs) have been shown to involve in the metabolic regulation. However, the underlying mechanisms of mitomiRs on regulating apoptosis under Cu exposure are still unclear. Here, we proved that Cu induced mitochondria-mediated apoptosis in porcine jejunal epithelial cells, concomitant with distinct reduction of mitomiR-504 in vivo and in vitro. The miR-504 mimic notably enhanced the mRNA and protein expressions of Bak1, Bax, Cleaved-caspase3 and Caspase-9, and significantly decreased the apoptosis rate and Bcl-2 mRNA and protein levels, indicating that overexpression of mitomiR-504 attenuated the Cu-induced mitochondria-mediated apoptosis. Besides, Bak1 was confirmed as a direct target of mitomiR-504 by the bioinformatics analysis and dual-luciferase reporter assay. Subsequently, transfection of siRNA targeting Bak1 significantly enhanced the alleviating effect of miR-504 mimic on the Cu-induced mitochondria-mediated apoptosis. Overall, these suggested that overexpression of mitomiR-504 alleviated the Cu-induced mitochondria-mediated apoptosis in jejunal epithelial cells by suppressing Bak1 expression. These findings are conducive to elucidating the mechanism of Cu-induced jejunal epithelial pathologies, providing a new research idea for the Cu toxicology.

Recent developments in antimicrobial growth promoters in chicken health: Opportunities and challenges

With a continuously increasing human population is an increasing global demand for food. People in countries with a higher socioeconomic status tend to switch their preferences from grains to meat and high-value foods. Their preference for chicken as a source of protein has grown by 70% over the last three decades. Many studies have shown the role of feed in regulating the animal gut microbiome and its impact on host health. The microbiome absorbs nutrients, digests foods, induces a mucosal immune response, maintains homeostasis, and regulates bioactive metabolites. These metabolic activities are influenced by the microbiota and diet. An imbalance in microbiota affects host physiology and progressively causes disorders and diseases. With the use of antibiotics, a shift from dysbiosis with a higher density of pathogens to homeostasis can occur. However, the progressive use of higher doses of antibiotics proved harmful and resulted in the emergence of multidrug-resistant microbes. As a result, the use of antibiotics as feed additives has been banned. Researchers, regulatory authorities, and managers in the poultry industry have assessed the challenges associated with these restrictions. Research has sought to identify alternatives to antibiotic growth promoters for poultry that do not have any adverse effects. Modulating the host intestinal microbiome by regulating dietary factors is much easier than manipulating host genetics. Research efforts have led to the identification of feed additives, including bacteriocins, immunostimulants, organic acids, phytogenics, prebiotics, probiotics, phytoncides, and bacteriophages. In contrast to focusing on one or more of these alternative bioadditives, an improved feed conversion ratio with enhanced poultry products is possible by employing a combination of feed additives. This article may be helpful in future research towards developing a sustainable poultry industry through the use of the proposed alternatives.