Copper requirement of baby pigs fed purified diets

Role of horizontally transferred copper resistance genes in Staphylococcus aureus and Listeria monocytogenes

Bacteria have evolved mechanisms which enable them to control intracellular concentrations of metals. In the case of transition metals, such as copper, iron and zinc, bacteria must ensure enough is available as a cofactor for enzymes whilst at the same time preventing the accumulation of excess concentrations, which can be toxic. Interestingly, metal homeostasis and resistance systems have been found to play important roles in virulence. This review will discuss the copper homeostasis and resistance systems in Staphylococcus aureus and Listeria monocytogenes and the implications that acquisition of additional copper resistance genes may have in these pathogens.

Dietary Copper Improves Intestinal Morphology via Modulating Intestinal Stem Cell Activity in Pigs

Simple Summary

Copper (Cu) is one of the essential trace elements for animal growth. Piglet intestinal epithelium undergoes a complete renewal driven by intestinal stem cells located at the crypt base. However, whether Cu improves intestinal morphology and development via modulating intestinal stem cell activity in pigs remains unclear. This study aimed to investigate the effects of dietary Cu during the weaning period on the intestinal morphology and development of weaned and finished pigs and explored the potential mechanism by culturing the intestinal organoids and treated them with Cu in vitro. The results indicated that Cu supplementation during the weaning period improves the intestinal morphology in finishing pigs by modulating the activity of intestinal stem cells.

Abstract

Copper (Cu) is an essential micronutrient for animals. Many studies have been conducted on the effects of dietary Cu on growth performance, intestinal morphology, and function of piglets. However, the underlying mechanism remains to be explored. Intestinal stem cells (ISC) drive the development and constant renewal of intestinal epithelium. Therefore, we hypothesized that dietary Cu affects piglets’ intestinal development via modulating ISC activity. A total of eighty-five 21-day-old piglets were randomly assigned to five groups, where 25, 50, 75, 100, and 125 mg CuSO₄/kg on a dry matter basis were supplemented to the basal diet at phase 1 (day 0 to 21). Increasing the dietary Cu concentration decreased (p < 0.05) villus width but increased (p < 0.001) the number of Ki67-positive cells. At phase 2 (day 22 to 163), the other 45 pigs were offered the same diets. Villus height in the 125 mg/kg Cu group was greater (p < 0.001) than in the other groups. Moreover, the effects of Cu on ISC activity in vitro were tested to explore the underlying mechanism. Compared to the control group, 10 μmol/L CuSO₄·5H₂O increased (p < 0.001) the organoid budding efficiency, crypt depth, and crypts per organoid. Dietary Cu improved the intestinal morphology of finishing pigs via promoting cell proliferation and modulating ISC activity.

Effects of dose and duration of dietary copper administration on hepatic lipid peroxidation and ultrastructure alteration in piglets' model

BACKGROUND

Copper is an essential microelement for animals and has been used at pharmacological doses in weaned piglets to improve growth performance. However, it also induces systemic oxidative stress after short-term feeding. The aim of this study was to investigate the effects of dose and duration of dietary copper on lipid peroxidation and oxidative stress status in model of weaned piglets.

METHODS

A total of 48 crossbred piglets (weaned at 21d, weight ∼8.2 kg) were randomly assigned into 4 groups of 12 in each. The control group and 3 treatment groups fed with basal diet supplemented with 20, 100 and 200 mg/kg copper as copper sulfate for 3 and 6 weeks, respectively.

RESULTS

Dietary copper supplementation significantly affected the activities of ALP, LDH, LIPC and the levels of Ca and TG in serum as well as the copper and zinc deposition in liver. Increased MDA concentrations, and decreased GPX, CP and CAT concentrations in serum were found in 0, 100 and 200 mg Cu/kg diet groups at 3 weeks post weaning. Hepatic lipid peroxidation was also induced in these groups indicated from hepatic SOD1, GPX1, CAT, CP, MT1A and MT2A transcriptional levels. Those adverse symptoms were alleviative at 6 weeks post weaning. The hepatic Cu and Zn concentrations, serum MDA concentrations, and serum CAT and GPX activities were significantly correlated with Actinobacillus, Lactobacillus, Sarcina, Helicobacter, Campylobacterales, which could affect the intestinal health further.

CONCLUSION

These results indicated that copper deficiency or over supplementation would affect the systemic lipid peroxidation. These adverse changes were not observed when the dietary copper concentration at 20 mg Cu/kg diet. The results suggested the appropriate dietary copper concentration is around 20 mg Cu/kg diet, and its range might be much stricter than we thought.

Optimal dietary copper requirements and relative bioavailability for weanling pigs fed either copper proteinate or tribasic copper chloride

Background

The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.

Methods

Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels (5, 10, 20, 40, 80, 160 mg/kg), and 2 mineral sources (tribasic Cu chloride, TBCC and copper proteinate, CuPro), as well as one negative control (0 mg/kg added Cu level) and one maximum allowed level treatment (200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.

Results

Increasing levels of Cu showed linear and quadratic responses (P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC (> 80 mg/kg) and CuPro (> 20 mg/kg) significantly decreased (P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases (P < 0.01) in bile, hepatic, and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities (alkaline phosphatase, ceruloplasmin, Cu, Zn-Superoxide dismutase (Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased (P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed CuPro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models (P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93-140 mg/kg from TBCC, and 63-98 mg/kg from CuPro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of CuPro relative to TBCC (100%) was 156-263% (P < 0.01).

Conclusion

The findings indicated that Cu recommendation from current NRC (5-6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from CuPro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.

Effect of Dietary Copper on Intestinal Microbiota and Antimicrobial Resistance Profiles of Escherichia coli in Weaned Piglets

Copper is an essential microelement for animals, and not only it has been used as a feed additive at pharmacological doses in swine production to improve growth performance, but it also has an effect on intestinal microbes by enhancing host bacterial resistance. However, there are few reports on the effects of pharmacological doses of copper on intestinal microorganisms and the antimicrobial resistance profiles of pathogenic bacteria, such as Escherichia coli, in pigs. Therefore, this study aimed to investigate the effects of pharmacological doses of copper on the microbial communities in the hindgut and the antimicrobial resistance profiles of E. coli in weaned piglets. Twenty-four healthy weaned piglets aged 21 ± 1 days and with an average weight of 7.27 ± 0.46 kg were randomly divided into four groups. The control group was fed a basal diet, while the treatment groups were fed a basal diet supplemented with 20, 100, or 200 mg copper/kg feed, in the form of CuSO₄. Anal swabs were collected at 0, 21, and 42 days of the trial, and E. coli was isolated. Meanwhile, the contents of the ileum and cecum from the control and 200 mg copper/kg feed groups were collected at 21 and 42 days for microbial community analysis and E. coli isolation. All isolated E. coli strains were used for antimicrobial resistance profile analysis. A pharmacological dose of copper did not significantly change the diversity, but significantly affected the composition, of microbial communities in the ileum and cecum. Moreover, it affected the microbial metabolic functions of energy metabolism, protein metabolism, and amino acid biosynthesis. Specifically, copper treatment increased the richness of E. coli in the hindgut and the rates of E. coli resistance to chloramphenicol and ciprofloxacin. Moreover, the rate of E. coli resistance to multiple drugs increased in the ileum of pigs fed a pharmacological dose of copper. Thus, a pharmacological dose of copper affected the composition of the microbial community, increased the antimicrobial resistance rates of intestinal E. coli, and was most likely harmful to the health of piglets at the early stage after weaning.

Effect of graded levels of iron, zinc, and copper supplementation in diets with low-phytate or normal barley on growth performance, bone characteristics, hematocrit volume, and zinc and copper balance of young swine1

Fifty crossbred barrows with an average initial age of 31 d and BW of 9.94 kg were used in a 28-d experiment to evaluate the effect of a low-phytic acid (LPA) barley mutant (M) M955, a near-isogenic progeny of the normal barley (NB) cultivar Harrington with about 90% less phytate than NB, to increase the utilization of Fe, Zn, and Cu compared with diets containing NB. The response criteria were growth performance, hematocrit volume, metacarpal bone characteristics, and the apparent absorption, retention, and excretion of Zn and Cu. The 2 barley cultivars (NB and M955) and the 5 trace mineral (TM) treatment concentrations of Fe and Zn (0, 25, 50, 75, and 100% of the requirement as FeSO(4) and ZnSO(4)) and Cu (0, 40, 80, 120, and 160% of the requirement as CuSO(4)) made 10 treatments in a factorial arrangement. Available P was equalized at 0.33% in all diets by adding monosodium phosphate to the basal diet containing NB, and all diets contained 0.65% Ca. Diets were adequate in all other nutrients. Barley and soybean meal were the only sources of phytate in the practical diets that also contained spray-dried whey. The barrows were fed the diets to appetite in meal form twice daily in individual metabolism crates. There were no barley cultivar x TM treatment interactions, and there were no differences between the NB and M955 barley cultivars for any of the response criteria measured. However, for the TM treatments, there were linear increases (P < or = 0.05) in ADFI, ADG, hematocrit volume, metacarpal bone breaking strength and ash weight, and the apparent absorption, retention, and excretion (mg/d) of Zn and Cu. In conclusion, the LPA barley had no effect on the response criteria in this experiment, apparently because of the small increase in the availability of the endogenous trace minerals in the practical diets containing M955 compared with NB. However, increasing the supplementation of Fe and Zn from 0 to 100% (160% for Cu) of the requirement resulted in linear increases in growth performance, hematocrit volume, metacarpal bone strength and ash weight, and the apparent absorption, retention, and excretion of Zn and Cu. Therefore, these results indicate that the inorganic trace mineral supplementation of practical diets for young pigs should not be less than the National Research Council requirements for swine.

The effects of low dietary copper intake during pregnancy on physiological fluids and reproductive performance of first-litter gilts

Seven pairs of first littermate gilts were used to study the influence of low copper supply and pregnancy on physiological fluids and reproductive performance of first-litter gilts. They were fed semi-purified diets containing either 2.13 or 12.25 micrograms/kg of Cu from 30 days of gestation through two weeks of lactation. Low-Cu gilts had lower plasma Cu in early- and mid- gestation and farrowed piglets with lower plasma Cu and higher plasma Zn concentrations (p < 0.05). Plasma Fe and Mn concentrations were not affected by Cu supply (p > 0.05). Plasma Cu and Fe levels of newborn piglets were lower than those of their dams (p < 0.05) but this was not true for plasma Zn and Mn (p > 0.05). Low-Cu gilts had lower Cu and higher Zn content in colostrum and also lower Cu in milk than control gilts (p < 0.05). No significant differences were found in Fe and Mn levels in colostrum and milk between the two treatments (p > 0.05). Colostrum was richer in Cu and Zn than milk (p < 0.05) but not in Fe and Mn (p > 0.05). The low-Cu diet did not affect (p > 0.05) weight changes during pregnancy. The duration of parturition was shorter for low-Cu than for control gilts (3.19h vs. 5.71h, p < 0.05). Control gilts farrowed larger litters than low-Cu gilts (9.71 vs. 7.57 piglets, p < 0.05). There were no significant differences in live litter weights at birth, one wk. or two wks. of age (p > 0.05). The results indicated that a low-Cu diet and pregnancy had some effect on plasma, colostrum and milk mineral concentrations, as well as on litter size of gilts. An interaction between Cu and Zn was found.

Dietary copper, simple sugars, and metabolic changes in pigs

Inadequate dietary copper is known to result in undesirable metabolic changes in rats and humans. Abnormal cardiac function, leading to sudden death, is a common finding when copper deficient rats are fed a 62% fructose diet. To further study the apparent mineral-carbohydrate relationship to cardiac physiology, 3 male and 3 female swine were randomly assigned to four groups (6 pigs per group) which were fed low copper (1.5 ppm) or copper supplemented (40 ppm) diets with 20% of calories from either fructose or glucose for 10 weeks. In agreement with results from other animal studies, copper deficient swine exhibited decreased plasma ceruloplasmin, erythrocyte superoxide dismutase and plasma lysyl oxidase activities and lowered serum copper. The copper deficient fructose group had the lowest aortic lysyl oxidase activity and hematocrit when compared to the other groups. The relative heart weight in the copper deficient fructose group was 93% greater than the other three dietary groups. The livers of copper deficient fructose fed pigs were also significantly larger. Two enzymes related to cardiac and hepatic function, aspartate and alanine aminotransferase were also measured. Copper deficiency significantly lowered alanine aminotransferase but there was no dietary effect on aspartate amino-transferase. The results of this project indicate that the pig is a sensitive model for the study of cardiovascular abnormalities which occur when fructose is consumed with a low copper diet.

Absence of abnormal erythrocyte superoxide dismutase, copper, or zinc levels in patients with retinitis pigmentosa

Blood samples obtained from 22 patients with retinitis pigmentosa, 6 unaffected family members, and 8 unrelated controls showed serum copper and zinc to be in the normal range, contrary to the results in earlier reports. Likewise no significant variation of erythrocyte superoxide dismutase (SOD) and catalase levels was found between the 3 groups or when the patients were grouped by sex, age, or genetic distribution. The SOD proteins from controls and retinitis pigmentosa patients had identical mobilities on gel electrophoresis, isoelectric points, and heat stabilities. Our studies do not support the use of copper, zinc, or SOD in the diagnosis or treatment of retinitis pigmentosa.

Changes in erythrocyte superoxide dismutase in a patient with copper deficiency

In a patient with typical copper deficiency, we found superoxide dismutase (SOD, 1.15.1.1) activity and copper in erythrocytes to be decreased to 52% and 46% of age-matched controls, respectively. However, these were not so markedly depleted as plasma copper (17%) or ceruloplasmin (20%). After copper replacement therapy, erythrocyte copper and SOD activity gradually returned to the control levels. Although certain abnormalities reported in copper deficiency in animals were expected, osmotic fragility of the liver and heart were not a feature as far as could be determined by electrocardiography and routine laboratory examinations. Probably a decrease of SOD to this extent is not severe enough to lead to superoxide-induced damage.