Effect of Dietary Copper Sources and Concentrations on Serum Lysozyme Concentration and Protegrin-1 Gene Expression in Weaning Piglets

Dietary copper improves intestinal structural integrity in juvenile grass carp (Ctenopharyngodon idella) probably related to its increased intestinal antioxidant capacity and apical junction complex

This research evaluated the effects of copper (Cu) on intestinal antioxidant capacity and apical junctional complex (AJC) in juvenile grass carp. A total of 1080 healthy juvenile grass carp (11.16 ± 0.01 g) were fed six diets including different dosages of Cu, namely 0, 2, 4, 6, 8 mg/kg (Cu citrate [CuCit] as Cu source) and 3 mg/kg (CuSO4·5H2O as Cu source). The trial lasted for 9 weeks. The findings revealed that dietary optimal Cu supplementation (2.2 to 4.1 mg/kg) promoted intestinal growth, including intestinal length, intestinal length index, intestinal weight, and intestinal somatic index (P < 0.05). Furthermore, optimal Cu boosted the intestinal mucosal barrier in juvenile grass carp. On the one hand, optimal Cu reduced diamine oxidase and D-lactate levels in serum (P < 0.05), reduced levels of the oxidative damage indicators malondialdehyde, reactive oxygen species (ROS), protein carbonyl, superoxide dismutase (P < 0.05), and catalase mRNA levels were elevated (P < 0.05), thus boosting intestinal antioxidant capacity, the binding protein Keap1a/1b/Nrf2 signaling pathway might be involved. Optimal Cu had no impact on glutathione peroxidase 1b (GPx1b) gene expression (P > 0.05). On the other hand, optimal Cu increased intestinal tight junction (TJ) proteins (except for claudin 15b) and adherens junction (AJ) proteins (E-cadherin, α-catenin, β-catenin, nectin and afadin) mRNA levels (P < 0.05), which could be connected to the signaling pathway formed by the Ras homolog gene family, member A (RhoA), Rho-associated kinase (ROCK), and myosin light chain kinase (MLCK). Finally, based on serum indicator D-lactate and intestinal oxidative damage index (ROS), Cu requirement (CuCit as Cu source) for juvenile grass carp from initial weight to final weight (from 11 to 173 g) was determined to be 4.14 and 4.12 mg/kg diet, respectively. This work may provide a theoretical foundation for identifying putative Cu regulation pathways on fish intestinal health.

Comparative effects of supplementary different copper forms on performance, protein efficiency, digestibility of nutrients, immune function and architecture of liver and kidney in growing rabbits

The various sources of supplemented copper had a different impact on the animal performance based on their bioavailability. The current study compared the effects of supplementary copper oxide (CuO), copper acetate (Cu-acetate) and copper nanoparticles (Cu-NP) on performance, immune function, nutrients digestibility and architecture of the liver and kidney of growing rabbits for eight weeks. Sixty rabbits (581 ± 6.56 g) were randomly allocated to four treatments as follows: basal diet, 100 mg copper/kg diet as CuO, 100 mg copper/kg diet as Cu-acetate and 50 mg copper/kg diet as Cu-NP. Cu-acetate and Cu-NP improved specific growth rate, final weight and daily weight gain. Cu-NP supplementation had higher feed intake, feed conversion, protein efficiency, hematocrit and hemoglobin values compared with other copper forms. All copper sources showed higher levels of serum complement component 3, Immunoglobulin M, lysozyme activity and the digestibility of nitrogen-free extract, dry matter and organic matter. As a result, increased nutritive values were detected when the rabbits were fed copper-supplemented diets. No liver and kidney architecture alterations were identified between the experimental groups. In conclusion, both dietary Cu-NP and Cu-acetate were more efficient than CuO in enhancing growth and seem promising in fattening rabbit nutrition.

A new insight on copper: Promotion of collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella)

Copper (Cu) is a trace element, essential for fish growth. In the current study, in addition to growth performance, we first explored the effects of Cu on collagen synthesis and myofiber growth and development in juvenile grass carp (Ctenopharyngodon idella). A total of 1080 fish (11.16 ± 0.01 g) were randomly divided into 6 treatments (3 replicates per treatment) to receive five doses of organic Cu, which were Cu citrate (CuCit) at 0.99 (basal diet), 2.19, 4.06, 6.15, and 8.07 mg/kg, and one dose of inorganic Cu (CuSO4·5H2O at 3.15 mg/kg), for 9 weeks. The results showed appropriate Cu level (4.06 mg/kg) enhanced growth performance, improved nutritional Cu status, and downregulated Cu-transporting ATPase 1 mRNA levels in the hepatopancreas, intestine, and muscle of juvenile grass carp. Meanwhile, collagen content in fish muscle was increased after Cu intake, which was probably due to the following pathways: (1) activating CTGF/TGF-β1/Smads signaling pathway to regulate collagen transcription; (2) upregulating of La ribonucleoprotein domain family 6 (LARP6) mRNA levels to regulate translation initiation; (3) increasing proline hydroxylase, lysine hydroxylase, and lysine oxidase activities to regulate posttranslational modifications. In addition, optimal Cu group increased myofiber diameters and the frequency of myofibers with diameter >50 μm, which might be associated with upregulation of cyclin B, cyclin D, cyclin E, proliferating cell nuclear antigen, myogenic determining factor (MyoD), myogenic factor 5, myogenin (MyoG), myogenic regulatory factor 4 and myosin heavy chain (MyHC) and downregulation of myostatin mRNA levels, increasing protein levels of MyoD, MyoG and MyHC in fish muscle. Finally, based on percentage weight gain (PWG), serum ceruloplasmin (Cp) activity and collagen content in fish muscle, Cu requirements were determined as 4.74, 4.37 and 4.62 mg/kg diet (CuCit as Cu source) of juvenile grass carp, respectively. Based on PWG and Cp activity, compared to CuSO4·5H2O, the efficacy of CuCit were 131.80% and 115.38%, respectively. Our findings provide new insights into Cu supplementation to promote muscle growth in fish, and help improve the overall productivity of aquaculture.

Effects of organic and inorganic copper on cecal microbiota and short-chain fatty acids in growing rabbits

Introduction

Copper (Cu) is an essential trace element for the growth of rabbits. This study aimed to investigate the effects of different Cu sources on intestinal microorganisms and short-chain fatty acids (SCFAs) in growing rabbits.

Methods

The experimental animals were randomly divided into four experimental groups, each group comprised eight replicates, with six rabbits (half male and half female) per replicate. And they were fed diets was composed by mixing the basal diet with 20 mg/kg Cu from one of the two inorganic Cu (cupric sulfate and dicopper chloride trihydroxide) or two organic Cu (cupric citrate and copper glycinate). Cecal contents of four rabbits were collected from four experimental groups for 16S rDNA gene amplification sequencing and gas chromatography analysis.

Results

Our results indicate that the organic Cu groups were less variable than the inorganic Cu groups. Compared with the inorganic Cu groups, the CuCit group had a significantly higher relative abundance of Rikenella Tissierella, Lachnospiraceae_NK3A20_group, Enterococcus, and Paeniclostridium, while the relative abundance of Novosphingobium and Ruminococcus were significantly lower (p < 0.05). The SCFAs level decreased in the organic Cu groups than in the inorganic Cu groups. Among the SCFAs, the butyric acid level significantly decreased in the CuCit group than in the CuSO₄ and CuCl₂ groups. The relative abundance of Rikenella and Turicibacter genera was significantly negatively correlated with the butyric acid level in the CuCit group compared with both inorganic Cu groups. These results revealed that the organic Cu (CuCit) group had an increased abundance of Rikenella, Enterococcus, Lachnospiraceae_NK3A20_group, and Turicibacter genera in the rabbit cecum.

Discussion

In summary, this study found that organic Cu and inorganic Cu sources had different effects on cecal microbiota composition and SCFAs in rabbits. The CuCit group had the unique higher relative abundance of genera Rikenella and Lachnospiraceae_NK3A20_group, which might be beneficial to the lower incidence of diarrhea in rabbits.

Antimicrobial Peptides in Farm Animals: An Updated Review on Its Diversity, Function, Modes of Action and Therapeutic Prospects

Antimicrobial peptides (AMPs) are the arsenals of the innate host defense system, exhibiting evolutionarily conserved characteristics that are present in practically all forms of life. Recent years have witnessed the emergence of antibiotic-resistant bacteria compounded with a slow discovery rate for new antibiotics that have necessitated scientific efforts to search for alternatives to antibiotics. Research on the identification of AMPs has generated very encouraging evidence that they curb infectious pathologies and are also useful as novel biologics to function as immunotherapeutic agents. Being innate, they exhibit the least cytotoxicity to the host and exerts a wide spectrum of biological activity including low resistance among microbes and increased wound healing actions. Notably, in veterinary science, the constant practice of massive doses of antibiotics with inappropriate withdrawal programs led to a high risk of livestock-associated antimicrobial resistance. Therefore, the world faces tremendous pressure for designing and devising strategies to mitigate the use of antibiotics in animals and keep it safe for posterity. In this review, we illustrate the diversity of farm animal-specific AMPs, and their biochemical foundations, mode of action, and prospective application in clinics. Subsequently, we present the data for their systematic classification under the major and minor groups, antipathogenic action, and allied bioactivities in the host. Finally, we address the limitations of their clinical implementation and envision areas for further advancement.

Effects of graded levels of cupric citrate on growth performance, antioxidant status, serum lipid metabolites and immunity, and tissue residues of trace elements in weaned pigs

OBJECTIVE

The goal of this study was to investigate the effects of cupric citrate (CuCit) on growth performance, antioxidant indices, serum lipid metabolites, serum immune indices, and tissue residues of copper (Cu), zinc, and iron in weaned pigs.

METHODS

A total of 180 weaned pigs (Duroc×Landrace×Large White) with an average body weight of 8.98±1.21 kg were randomly assigned to a corn-soybean meal control ration, or 4 similar rations with 30, 60, 120, or 240 mg/kg Cu as CuCit. All diets contained 10 mg/kg Cu as cupric sulfate from the vitamin-mineral premix. The experiment was divided into two phases: 0 to 14 d (phase 1) and 15 to 28 d (phase 2).

RESULTS

Average daily gain (ADG; linearly, p<0.01) and average daily feed intake (ADFI; linearly and quadratically, p<0.05) were affected by an increase in CuCit during phase 2. Overall period, ADG (p<0.05) and ADFI (p<0.01) were linearly increased with increasing dietary levels of CuCit. Serum malondialdehyde concentrations (p<0.05) and glutathione peroxidase activity (p<0.01) linearly decreased and increased respectively with an increase in CuCit. Serum levels of Cu-Zn superoxide dismutase were linearly affected with an increase in CuCit (p<0.01). Hepatic malondialdehyde levels decreased with an increase in CuCit (linearly and quadratically, p<0.01). Serum total cholesterol concentrations were quadratically affected (p<0.05) and decreased in pigs fed Cu as CuCit at 60 and 120 mg/kg and increased in pigs fed 240 mg/kg Cu as CuCit. Serum high-density lipoprotein concentrations were linearly affected with an increase in CuCit (p<0.01). Serum IL-1β levels were quadratically affected (p<0.05) by dietary treatment. Compared with other treatments, 240 mg/kg Cu from CuCit quadratically increased hepatic (p<0.01) and renal (p<0.05) Cu concentrations, and quadratically decreased hepatic and renal iron concentrations (p<0.05).

CONCLUSION

Cu administered in the form of CuCit at a dosage range of 30 to 60 mg/kg, effectively enhanced the growth performance and antioxidant status of weaned pigs.