Effect of pharmacological intakes of zinc and copper on growth performance, circulating cytokines and gut microbiota of newly weaned piglets challenged with coliform lipopolysaccharides

Influence of copper source and dietary inclusion level on growth performance of weaned pigs and expression of trace element related genes in the small intestine

Copper is routinely supplemented to weanling pig diets at concentrations above nutritional requirements to enhance growth performance. We hypothesised that this effect depends on the source of Cu and its dietary concentration. We tested this in weaned pigs (26 d of age) over a 35-d period using a 2 × 3 factorial arrangement with two Cu-sources (CuSO4 and Cu2O, monovalent copper oxide, CoRouge®) and three supplementary dietary Cu-levels (15, 80 and 160 mg Cu/kg) as respective factors. Increasing Cu level linearly increased (P < 0.001) final BW and daily gain. These effects tended (P = 0.09) to be greater with Cu2O than CuSO4. Feed conversion ratio decreased linearly (P < 0.001) with increasing dietary Cu content, independent of Cu source. Plasma Cu, Zn and Fe levels were unaffected, whereas liver Cu content increased quadratically (P < 0.001) with increasing dietary Cu content, with a larger increase (P < 0.001) with CuSO4 than Cu2O. Bile Cu content increased quadratically (P = 0.025) with increasing Cu content, irrespective of Cu source. RT-qPCR analysis revealed that increasing Cu content quadratically (P = 0.009) increased duodenal but not ileal metallothionein 1A (MT1A) mRNA, with greater effect (P = 0.010) of CuSO4. Regardless of the Cu source, increasing Cu dose linearly increased (P = 0.006) duodenal DMT1/SLC11A2 mRNA but decreased ZIP4/SLC39A4 mRNA in duodenum (P < 0.001) and ileum (P < 0.005). ZnT10/SLC30A10 mRNA was significantly (P = 0.021) and numerically (P = 0.061) greater with Cu2O compared to CuSO4, in duodenum and ileum, respectively. Copper content quadratically modulated duodenal but not ileal transferrin receptor (P = 0.029) and ferric reductase CYBRD1 mRNA (P = 0.022). In hypothalamus, high Cu dose (P = 0.024) and Cu2O as source (P = 0.028) reduced corticotropin-releasing hormone (CRH) mRNA. Low versus high CuSO4 increased corticotropin-releasing hormone receptor (CRHR2) mRNA, while low Cu2O had the opposite effect (P = 0.009). In conclusion, incremental Cu intake enhanced growth performance, with a tendency for a greater effect of Cu2O. The lower increase in duodenal MT1A mRNA and liver Cu content indicates that less Cu from Cu2O was absorbed by gut and sequestered in liver. Thus, high Cu absorption is not essential for its growth-promoting effect and dietary Cu may affect intestinal Fe and Zn absorption via the active, transcellular route. The effects on hypothalamic CRH and CRHR2 expression indicate a role for the hypothalamus in mediating the effects of Cu on growth performance.

A Systematic Review and Meta-Analysis of the Effects of Various Sources and Amounts of Copper on Nursery Piglets

This study evaluated the impact of different dietary levels and sources of copper on the growth performance of nursery piglets through a combination of systematic review and meta-analysis. The database for this study was created using articles selected from major electronic databases. Data analysis involved forest plots and analysis of variance using mixed-effects models. The database included 63 articles published between 1990 and 2021, comprising 21,113 piglets in 946 treatments. Positive effects of supranutritional levels of copper from both inorganic and organic sources on the growth performance of nursery piglets were detected using Forest plots and analysis of variance (p < 0.001). Using mixed models, it was observed that piglet performance is influenced by body weight (p < 0.001), age (p < 0.001), and copper intake (p < 0.001). Both organic and inorganic sources of copper at supranutritional levels (>81 mg Cu/kg of diet) improved the performance of nursery piglets, but levels higher than 201 mg Cu/kg of diet did not further improve growth performance compared to 80-200 mg Cu/kg of diet. The feed conversion was worse in piglets fed with inorganic Cu sources (p < 0.001). In conclusion, dietary Cu supplementation influenced the weight gain and feed conversion rate in weaned piglets, particularly during the first few weeks post-weaning. Levels of 81 and 200 mg Cu/kg improved growth performance, but no further benefits were obtained for higher levels.

Effects of monensin sodium and live attenuated oocyst vaccine as coccidiosis management programs on productive performance, bone quality and mineral utilisation in broiler chickens

1. The following study was conducted to evaluate the influence of coccidiosis vaccine-induced metabolic stress on the utilisation of minerals in broilers. The starter, grower and finisher phase diets, including macro- and micro minerals at the recommended levels for the breed standards, were fed to chickens between 1 and 39 d of age.2. A total of 486, one-d-old male broilers were randomly distributed into three coccidiosis management programs (CMP) with six replications each. The CMP comprised: monensin sodium (MON), coccidiosis vaccine (VAC), not treated with MON or VAC (CNT).3. No significant differences between CMP were observed for body weight and weight gain among treatments. When compared to the CNT, the VAC program increased feed intake (P < 0.05) between d 1 to 13 and 14 to 26, while FCR worsened in the latter (P < 0.05) and the former (P = 0.05) periods.4. For birds in the MON and VAC programs, tibia bone length at d 13 and bone diameter at d 39 were both enhanced (P < 0.05). Meat yield characteristics were comparable among the CMP.5. Faeces of VAC birds had a lower (P < 0.05) dry matter and ash content than those in CNT program. CMP had no effect on serum or bone mineral concentrations at any point in time. For minerals, Mg, Na, and K faecal excretion was reduced (P < 0.01) as a result of the VAC program at d 13 with a trend at d 26.6. Compared to the CNT, the VAC program decreased the percentage ratio of drip loss (P = 0.08), water holding capacity (P < 0.01) and cooking loss (P < 0.01) in breast meat.7. Overall, the results showed that current broiler industry practices are capable of meeting the mineral needs of broilers vaccinated against coccidiosis.

The Effects of Dietary Manganese and Selenium on Growth and the Fecal Microbiota of Nursery Piglets

The objective of this study was to determine the impact of varying dietary manganese and selenium concentrations, antioxidant cofactors, on the growth performance and fecal microbial populations of nursery pigs. The piglets (N = 120) were blocked by weight (5.22 ± 0.7 kg) and sex. The pens (n = 5/treatment) within a block were randomly assigned to diets in a 2 × 3 factorial design to examine the effects of Se (0.1 and 0.3 mg/kg added Se) and Mn (0, 12, and 24 mg/kg added Mn) and were fed in three phases (P1 = d 1-7, P2 = d 8-21, P3 = d 22-35). The pigs and orts were weighed weekly. Fecal samples were collected d 0 and 35 for 16S rRNA bacterial gene sequencing and VFA analysis. The data were analyzed as factorial via GLM in SAS. There was a linear response (p < 0.05) in overall ADG across dietary Mn. Supplementing 24 mg/kg Mn tended to decrease (p < 0.10) the relative abundance of many bacteria possessing pathogenic traits relative to Mn controls. Meanwhile, increasing Mn concentration tended to foster the growth of bacteria correlated with gut health and improved growth (p < 0.10). The data from this study provide preliminary evidence on the positive effects of manganese on growth and gut health of nursery pigs.

Effect of Red-Beetroot-Supplemented Diet on Gut Microbiota Composition and Metabolite Profile of Weaned Pigs-A Pilot Study

Red beetroot is a well-recognized and established source of bioactive compounds (e.g., betalains and polyphenols) with anti-inflammatory and antimicrobial properties. It is proposed as a potential alternative to zinc oxide with a focus on gut microbiota modulation and metabolite production. In this study, weaned pigs aged 28 days were fed either a control diet, a diet supplemented with zinc oxide (3000 mg/kg), or 2% and 4% pulverized whole red beetroot (CON, ZNO, RB2, and RB4; respectively) for 14 days. After pigs were euthanized, blood and digesta samples were collected for microbial composition and metabolite analyses. The results showed that the diet supplemented with red beetroot at 2% improved the gut microbial richness relative to other diets but marginally influenced the cecal microbial diversity compared to a zinc-oxide-supplemented diet. A further increase in red beetroot levels (4%-RB4) led to loss in cecal diversity and decreased short chain fatty acids and secondary bile acid concentrations. Also, an increased Proteobacteria abundance, presumably due to increased lactate/lactic-acid-producing bacteria was observed. In summary, red beetroot contains several components conceived to improve the gut microbiota and metabolite output of weaned pigs. Future studies investigating individual components of red beetroot will better elucidate their contributions to gut microbiota modulation and pig health.

Maternal and/or post-weaning supplementation with Bacillus altitudinis spores modulates the microbial composition of colostrum, digesta and faeces in pigs

This study examined the effects of maternal and/or post-weaning Bacillus altitudinis supplementation on the microbiota in sow colostrum and faeces, and offspring digesta and faeces. Sows (n = 12/group) were assigned to: (1) standard diet (CON), or (2) CON supplemented with probiotic B. altitudinis spores (PRO) from day (d)100 of gestation to weaning (d26 of lactation). At weaning, offspring were assigned to CON or PRO for 28d, resulting in: (1) CON/CON, (2) CON/PRO, (3) PRO/CON, and (4) PRO/PRO, after which all received CON. Samples were collected from sows and selected offspring (n = 10/group) for 16S rRNA gene sequencing. Rothia was more abundant in PRO sow colostrum. Sow faeces were not impacted but differences were identified in offspring faeces and digesta. Most were in the ileal digesta between PRO/CON and CON/CON on d8 post-weaning; i.e. Bacteroidota, Alloprevotella, Prevotella, Prevotellaceae, Turicibacter, Catenibacterium and Blautia were more abundant in PRO/CON, with Firmicutes and Blautia more abundant in PRO/PRO compared with CON/CON. Lactobacillus was more abundant in PRO/CON faeces on d118 post-weaning. This increased abundance of polysaccharide-fermenters (Prevotella, Alloprevotella, Prevotellaceae), butyrate-producers (Blautia) and Lactobacillus likely contributed to previously reported improvements in growth performance. Overall, maternal, rather than post-weaning, probiotic supplementation had the greatest impact on intestinal microbiota.

Supplementation with Antimicrobial Peptides or a Tannic Acid Can Effectively Replace the Pharmacological Effects of Zinc Oxide in the Early Stages of Weaning Piglets

Zinc oxide (ZnO) harms the environment and can potentially increase the number of drug-resistant bacteria. Therefore, there is an urgent need to find safe and effective alternatives to improve gut health and reduce the incidence of diarrhea in weaned piglets. This study conducted an antibacterial test of ZnO, antibacterial peptides (AMPs), and tannic acid (TA) in vitro. Thirty piglets were randomly allotted to one of the following three dietary treatments: ZnO (2000 mg/kg ZnO diet), AMPs (700 mg/kg AMPs diet), and TA (1000 mg/kg TA diet). The results showed that the minimum inhibitory concentrations of ZnO and TA against Escherichia coli and Salmonella were lower than those of AMPs, and the minimum inhibitory concentrations of ZnO, AMPs, and TA against Staphylococcus aureus were the same. Compared to ZnO, AMPs increased the digestibility of dry, organic matter and the crude fat. Additionally, TA significantly (p < 0.05) increased the digestibility of dry and organic matter. On experimental day 14, the plasma interleukin-6 (IL-6) content of piglets supplemented with AMPs and TA was increased significantly (p < 0.05). On experimental day 28, alanine aminotransferase activity in the plasma of weaned piglets in the ZnO and TA groups was significantly (p < 0.05) higher than in piglets in the AMPs group. The levels of plasma IL-6 and immunoglobulin M (IgM) were significantly higher (p < 0.05) in the ZnO and AMPs groups than in the TA group. On experimental days 14 and 28, no significant differences were observed in the antioxidant capacity among the three experimental groups. Intestinal microbial diversity analysis showed that the Chao1 and ACE indices of piglets in the AMPs group were significantly higher (p < 0.05) than those in the ZnO and TA groups. At the genus level, the relative abundance of Treponema_2 was higher in the feces of piglets fed a diet supplemented with TA than in those fed diet supplemented with ZnO (p < 0.05). The relative abundance of Lachnospiraceae was higher in the feces of piglets fed a diet supplemented with AMPs than in those fed diet supplemented with ZnO or TA. Overall, AMPs and TA could be added to feed as substitutes for ZnO to reduce diarrhea, improve nutrient digestibility and immunity, and increase the abundance of beneficial intestinal bacteria in weaned piglets.

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.

Comparison of the Microbiome-Metabolome Response to Copper Sulfate and Copper Glycinate in Growing Pigs

This study aims to compare the fecal microbiome-metabolome response to copper sulfate (CuSO₄) and copper glycinate (Cu-Gly) in pigs. Twelve Meishan gilts were allocated into the CuSO₄ group and the Cu-Gly group (fed on a basal diet supplemented with 60 mg/kg copper from CuSO₄ or Cu-Gly) paired in litter and body weight. After a two-week feeding trial, the Cu-Gly group had a higher copper digestibility, blood hemoglobin, and platelet volume and higher levels of plasma iron and insulin-like growth factor-1 than the CuSO₄ group. The Cu-Gly treatment increased the abundance of the Lachnospiraceae family and the genera Lachnospiraceae XPB1014, Corprococcus_3, Anaerorhabdus_furcosa_group, Lachnospiraceae_FCS020_group, and Lachnospiraceae_NK4B4_group and decreased the abundance of the Synergistetes phylum and Peptostreptococcaceae family compared to the CuSO₄ treatment. Moreover, the Cu-Gly group had a lower concentration of 20-Oxo-leukotriene E4 and higher concentrations of butyric acid, pentanoic acid, isopentanoic acid, coumarin, and Nb-p-Coumaroyl-tryptamine than the CuSO₄ group. The abundance of Synergistetes was positively correlated with the fecal copper content and negatively correlated with the fecal butyric acid content. The abundance of the Lachnospiraceae_XPB1014_group genus was positively correlated with the plasma iron level and fecal contents of coumarin and butyric acid. In conclusion, Cu-Gly and CuSO₄ could differentially affect fecal microbiota and metabolites, which partially contributes to the intestinal health of pigs in different manners.

Low-dose florfenicol and copper combined exposure during early life induced health risks by affecting gut microbiota and metabolome in SD rats

The potential health risks associated with simultaneous presence of residues of heavy metals and antibiotics in the environment and food have been of wide concern. However, the adverse health effects of combined heavy metal and antibiotic exposure at low doses remain unclear. In this study, the effects of combined exposure to florfenicol and copper at low doses during early life on toxicity, gut microbiota, drug resistance genes, and the fecal metabolome were investigated in Sprague-Dawley (SD) rats. The results showed that combined exposure induced inflammatory responses and visceral injury as well as faster weight gain compared with florfenicol or copper exposure alone. Alpha and beta diversity indices indicated that the composition of the gut microbiota and the abundance of bacteria related to energy intake and disease in the combined exposure group were significantly altered. The increase in resistance genes (floR, fexA) induced by florfenicol exposure was suppressed under combined exposure to florfenicol and copper. The fecal metabolome also demonstrated that metabolic pathways related to energy intake and liver injury were significantly affected in the combined exposure group. In conclusion, this study shows that combined exposure to florfenicol and copper during early life can pose a nonnegligible health risk even if the exposure concentration of florfenicol or copper is below the safe limit.

Effect of Long-Term and Short-Term Imbalanced Zn Manipulation on Gut Microbiota and Screening for Microbial Markers Sensitive to Zinc Status

Zinc (Zn) imbalance is a common single-nutrient disorder worldwide, but little is known about the short-term and long-term effects of imbalanced dietary zinc in the intestinal microbiome. Here, 3-week-old C57BL/6 mice were fed diets supplemented with Zn at the doses of 0 (low Zn), 30 (control Zn), 150 (high Zn), and 600 mg/kg of body weight (excess Zn) for 4 weeks (short term) and 8 weeks (long term). The gut bacterial composition at the phyla, genus, and species levels were changed as the result of the imbalanced Zn diet (e.g., Lactobacillus reuteri and Akkermansia muciniphila). Moreover, pathways including carbohydrate, glycan, and nucleotide metabolism were decreased by a short-term low-Zn diet. Valeriate production was suppressed by a long-term low-Zn diet. Pathways such as drug resistance and infectious diseases were upregulated in high- and excess-Zn diets over 4-week and 8-week intervals. Long-term zinc fortification doses, especially at the high-Zn level, suppressed the abundance of short-chain fatty acids (SCFAs)-producing genera as well as the concentrations of metabolites. Finally, Melainabacteria (phylum) and Desulfovibrio sp. strain ABHU2SB (species) were identified to be potential markers for Zn status with high accuracy (area under the curve [AUC], >0.8). Collectively, this study identified significant changes in gut microbial composition and its metabolite concentration in altered Zn-fed mice and the relevant microbial markers for Zn status. IMPORTANCE Zn insufficiency is an essential health problem in developing countries. To prevent the occurrence of zinc deficit, zinc fortification and supplementation are widely used. However, in developed countries, the amounts of Zn consumed often exceed the tolerable upper intake limit. Our results demonstrated that dietary Zn is an essential mediator of microbial community structure and that both Zn deficiency and Zn overdose can generate a dysbiosis in the gut microbiota. Moreover, specific microbial biomarkers of Zn status were identified and correlated with serum Zn level. Our study found that a short-term low-Zn diet (0 mg/kg) and a long-term high-zinc diet (150 mg/kg) had obvious negative effects in a mouse model. Thus, these results indicate that the provision and duration of supplemental Zn should be approached with caution.

Recent Advances in Understanding the Influence of Zinc, Copper, and Manganese on the Gastrointestinal Environment of Pigs and Poultry

Simple Summary

Pigs and poultry, similar to humans, need regular consumption of zinc, copper, and manganese for normal functioning. To ensure adequate dietary intake, and prevent deficiency, their diets are supplemented with sufficient, often excessive, levels of these minerals or even at higher levels, which have been associated with improvements in their health and/or growth. However, if provided in excess, mineral quantities beyond those required are simply excreted from the animal, which is associated with negative consequences for the environment and even the development of antimicrobial resistance. Therefore, it is of great interest to better understand the dynamics of zinc, copper, and manganese in the intestine of pigs and poultry following consumption of supplemented diets, and how the requirements and benefits related to these minerals can be optimized and negative impacts minimized. The intestine of pigs and poultry contains vast numbers of microorganisms, notably bacteria, that continually interact with, and influence, their host. This review explores the influence of zinc, copper, and manganese on these interactions and how novel forms of these minerals have the potential to maximize their delivery and benefits, while limiting any negative consequences.

Abstract

Zinc, copper, and manganese are prominent essential trace (or micro) minerals, being required in small, but adequate, amounts by pigs and poultry for normal biological functioning. Feed is a source of trace minerals for pigs and poultry but variable bioavailability in typical feed ingredients means that supplementation with low-cost oxides and sulphates has become common practice. Such trace mineral supplementation often provides significant ‘safety margins’, while copper and zinc have been supplemented at supra-nutritional (or pharmacological) levels to improve health and/or growth performance. Regulatory mechanisms ensure that much of this oversupply is excreted by the host into the environment, which can be toxic to plants and microorganisms or promote antimicrobial resistance in microbes, and thus supplying trace minerals more precisely to pigs and poultry is necessary. The gastrointestinal tract is thus central to the maintenance of trace mineral homeostasis and the provision of supra-nutritional or pharmacological levels is associated with modification of the gut environment, such as the microbiome. This review, therefore, considers recent advances in understanding the influence of zinc, copper, and manganese on the gastrointestinal environment of pigs and poultry, including more novel, alternative sources seeking to maintain supra-nutritional benefits with minimal environmental impact.

Effects of Zinc Oxide/Zeolite on Intestinal Morphology, Intestinal Microflora, and Diarrhea Rates in Weaned Piglets

This experiment was conducted to investigate the effects of zinc oxide/zeolite on growth performance, serum biochemistry, intestinal morphology, and microflora of weaned piglets. Two hundred and fifty-six weaned piglets (Duroc × Landrace × Large) at 21 days of age were randomly assigned to 2 groups with 8 replicates and 16 piglets in each pen. The diets of high dose of zinc oxide group (HD-ZnO) supplemented with 1500 mg/kg zinc as zinc oxide, but the diet of experimental group supplemented with 500 mg/kg zinc as zinc oxide that supported on zeolite (SR-ZnO). The experiment was conducted for 2 weeks after weanling. The results showed replacement of high-dosed zinc oxide by SR-ZnO had no significant effects on growth performance and intestinal morphology. However, the dietary supplementation of SR-ZnO reduced the diarrhea rate (P < 0.05), increased the activity of serum alkaline phosphatase (ALP) (P < 0.01), and tended to reduce zinc release in stomach (P = 0.06) and increase serum total protein (TP) (P = 0.07). Although there were no significant effects in ileal microflora on α diversity, the abundance of Campylobacters was found significantly decreased (P < 0.05), whereas the abundance of Clostridium was increased (P < 0.05) after lower-dosed SR-ZnO replacement. It is revealed that replacement of HD-ZnO (1500 mg/kg) by SR-ZnO (500 mg/kg) in creep feed could improve the zinc bioavailability, regulate the intestinal flora, and alleviate the postweaning diarrhea in weaned piglets. Accordingly, the application of SR-ZnO would reduce the zinc in feed and therefore benefits for the ecological environment.

Digestibility and metabolism of copper in diets for pigs and influence of dietary copper on growth performance, intestinal health, and overall immune status: a review

The current contribution reviews absorption and metabolism of copper (Cu), Cu deficiency, Cu toxicity, Cu bioavailability, and effects of pharmacological levels of Cu on growth performance and intestinal health of pigs. Copper is a micro mineral involved in metabolic reactions including cellular respiration, tissue pigmentation, hemoglobin formation, and connective tissue development. Copper is mostly absorbed in the upper gastrointestinal tract, particularly in the duodenum, but some Cu is absorbed in the stomach. One way to evaluate the efficacy of sources of Cu is to measure relative bioavailability where responses include tissue concentrations of Cu, concentrations of metalloproteins, and enzymatic activity of animals fed test diets containing graded levels of Cu. The requirement for Cu by pigs is 5 to 10 mg/kg diet, however, Cu can be included at growth-promoting levels (i.e., 75 to 250 mg/kg diet) in diets for weanling and growing pigs to reduce post-weaning diarrhea and improve growth performance. The consistently observed improvement in growth performance upon Cu supplementation is likely a result of increases in lipase activity, growth hormone secretion, and expression of genes involved in post-absorptive metabolism of lipids. The growth-promoting effects of dietary Cu have also been attributed to its bacteriostatic and bactericidal properties because Cu may change bacterial populations in the intestine, and thereby reduce inflammation caused by pathogens. However, further research is needed to determine potential interactions between Cu and non-nutritive feed additives (e.g., enzymes, probiotics, phytobiotics), and the optimum quantity of Cu as well as the optimum duration of feeding supplemental Cu in diets for pigs should be further investigated. These gaps needs to be addressed to maximize inclusion of Cu in diets to improve growth performance while minimizing diseases and mortality.

The Role of Salmonella Genomic Island 4 in Metal Tolerance of Salmonella enterica Serovar I 4,[5],12:i:- Pork Outbreak Isolate USDA15WA-1

Multidrug-resistant (MDR; resistance to >3 antimicrobial classes) Salmonella enterica serovar I 4,[5],12:i:- strains were linked to a 2015 foodborne outbreak from pork. Strain USDA15WA-1, associated with the outbreak, harbors an MDR module and the metal tolerance element Salmonella Genomic Island 4 (SGI-4). Characterization of SGI-4 revealed that conjugational transfer of SGI-4 resulted in the mobile genetic element (MGE) replicating as a plasmid or integrating into the chromosome. Tolerance to copper, arsenic, and antimony compounds was increased in Salmonella strains containing SGI-4 compared to strains lacking the MGE. Following Salmonella exposure to copper, RNA-seq transcriptional analysis demonstrated significant differential expression of diverse genes and pathways, including induction of at least 38 metal tolerance genes (copper, arsenic, silver, and mercury). Evaluation of swine administered elevated concentrations of zinc oxide (2000 mg/kg) and copper sulfate (200 mg/kg) as an antimicrobial feed additive (Zn+Cu) in their diet for four weeks prior to and three weeks post-inoculation with serovar I 4,[5],12:i:- indicated that Salmonella shedding levels declined at a slower rate in pigs receiving in-feed Zn+Cu compared to control pigs (no Zn+Cu). The presence of metal tolerance genes in MDR Salmonella serovar I 4,[5],12:i:- may provide benefits for environmental survival or swine colonization in metal-containing settings.

Effects of copper and zinc sources and inclusion levels of copper on weanling pig performance and intestinal microbiota

A 42-d experiment was conducted to evaluate the effect of Cu and Zn source and Cu level on pig performance, mineral status, bacterial modulation, and the presence of antimicrobial-resistant genes in isolates of Enterococcus spp. At weaning, 528 pigs (5.9 ± 0.50 kg) were allotted to 48 pens of a randomized complete block design in a 2 × 2 factorial arrangement with two Cu and Zn sources (SF: sulfate and HCl: hydroxychloride) and two Cu levels (15 and 160 mg/kg). As a challenge, the pigs were reared in dirty pens used by a previous commercial batch. Two-phase diets were offered: the pre-starter (PS) phase from day 1 to 14 and the starter phase (ST) from day 14 to 42. At days 14 and 42, pigs were individually weighed and blood samples from one pig per pen were taken. At the end of the experiment, one pig per pen was euthanized to collect the samples. Feeding high levels of Cu increased body weight (BW) from 16.6 to 17.7 kg (P < 0.001). Furthermore, average daily gain, gain to feed (G:F) ratio, average daily feed intake (ADFI), and mineral status were enhanced with Cu at 160 mg/kg (P < 0.05) compared with Cu at 15 mg/kg. There was no effect of the interaction between source × level on any of the growth performance responses except for ADFI (P = 0.004) and G:F (P = 0.029) at the end of the ST period and for G:F (P = 0.006) for entire nursery period (day 0 to 42). At the end of the ST period, pigs fed Cu at 160 mg/kg as HCl had not only higher ADFI but also lower G:F than those fed Cu as SF at 160 mg/kg. Meanwhile, for the entire nursery period, G:F did not differ between pigs fed Cu at 160 mg/kg as HCl or SF. In colonic digesta, the relative abundance of Streptococcus, Enterobacter, Escherichia, among others, decreased (P-adjust < 0.05), while Lachnospira and Roseburia tended (P-adjust < 0.10) to increase in pigs fed Cu at 160 mg/kg as HCl compared with those fed Cu SF at 160 mg/kg. An increase (P-adjust < 0.05) in Methanosphaera and Roseburia was observed in pigs fed Cu at 160 mg/kg. From colon digesta, Enterococcus spp. was isolated in 40 samples, being E. faecalis the most dominating (65%) regardless of the experimental diet. Genes of ermB (7.5%) and tetM (5%) were identified. No genes for Cu (tcrB) or vancomycin (vanA, vanB, vanC1, and vanC2) were detected. In conclusion, European Union permissible levels of Cu (160 mg/kg), of both sources, were able to increase performance, mineral status, and bacterial modulation compared with nutritional level. Different effects on growth performance, mineral tissue content, and microbial modulation were observed between Cu and Zn sources.

Effects of reducing dietary crude protein concentration and supplementation with laminarin or zinc oxide on the faecal scores and colonic microbiota in newly weaned pigs

A 2 × 3 factorial design experiment was conducted to examine the effects of reducing dietary crude protein (CP) concentration and/or supplementation with zinc oxide (ZnO) or laminarin on faecal scores (FS) and the large intestinal microbiota post-weaning (PW). One hundred and forty-four pigs were assigned to (T1) 21% standard CP diet (SCP); (T2) SCP + ZnO (SCP ZnO); (T3) SCP + laminarin (SCP LAM); (T4) 18% low CP diet (LCP); (T5) LCP + ZnO (LCP ZnO); and (T6) LCP + laminarin (LCP LAM; n = 8 replicates/treatment). The LCP diet had no effect on FS (p > .05), it increased two measures of alpha diversity, reduced Bacteroidetes and increased Enterobacteriaceae and Helicobacteraceae in the colon relative to the SCP diet (p < .05). ZnO supplementation reduced FS and increased Ruminococcaceae compared with unsupplemented pigs (p < .05). ZnO supplementation increased the genera Frisingicoccus (p < .001), Lachnoclostridium (p < .05) and Peptoclostridium (p < .05) in the colon and reduced total caecal volatile fatty acids (VFA) concentrations compared with the unsupplemented and laminarin-supplemented pigs. Laminarin supplementation reduced FS compared with unsupplemented pigs but had no major effect on the microbiota compared with the unsupplemented pigs. There were CP concentration × additive interactions on both Firmicutes and Proteobacteria. Firmicutes were increased in the LCP ZnO group compared with the LCP group, but there was no difference between the SCP groups. Proteobacteria were reduced in the LCP ZnO group compared with the LCP and LCP LAM groups (p < .05), but there was no difference between the SCP groups. In conclusion, reducing CP did not improve FS; it increased the relative abundance of Enterobacteriaceae; however, it also increased bacterial diversity. Supplementation with ZnO and laminarin improved FS, although all groups had scores within the healthy range. ZnO altered the large intestinal microbiota and VFA concentrations; however, laminarin did not enhance these parameters, suggesting these compounds have differing modes of action.

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.

Interactions between host and gut microbiota in domestic pigs: a review

It is well established that pig gut microbiota plays a critical role in maintaining metabolic homeostasis as well as in a myriad of physiological, neurological and immunological functions; including protection from pathogens and digestion of food materials - some of which would be otherwise indigestible by the pig. A rich and diverse gut microbial ecosystem (balanced microbiota) is the hallmark of good health; while qualitative and quantitative perturbations in the microbial composition can lead to development of various diseases. Alternatively, diseases caused by stressors or other factors have been shown to negatively impact the microbiota. This review focuses primarily on how commensal microorganisms in the gastrointestinal tract of pigs influence biochemical, physiological, immunological, and metabolic processes within the host animal.

Effects of copper hydroxychloride on growth performance and abundance of genes involved in lipid metabolism of growing pigs

An experiment was conducted to test the hypothesis that copper (Cu) hydroxychloride improves growth performance by upregulating the mRNA transcription of genes involved in lipid metabolism of pigs fed a diet based on corn, soybean meal (SBM), and distillers dried grains with solubles (DDGS). Thirty-two pigs (15.05 ± 0.98 kg) were allotted to 2 dietary treatments with 2 pigs per pen for a total of 8 replicate pens per treatment. Pigs were fed a corn-SBM-DDGS control diet that included Cu to meet the requirement. A second diet was formulated by adding 150 mg Cu/kg from copper hydroxychloride to the control diet. On the last day of the experiment, one pig per pen was sacrificed, and samples from liver, skeletal muscle, and subcutaneous adipose tissue were collected to analyze relative mRNA abundance of genes involved in lipid metabolism. Results indicated that overall ADG and G:F were greater (P < 0.05) for pigs fed the diet containing copper hydroxychloride compared with pigs fed the control diet. Pigs fed the diet supplemented with copper hydroxychloride also had increased (P < 0.05) abundance of cluster of differentiation 36 in the liver and increased (P < 0.05) abundance of fatty acid-binding protein 4 and lipoprotein lipase in subcutaneous adipose tissue. Inclusion of copper hydroxychloride also tended to increase (P < 0.10) the abundance of fatty acid-binding protein 1, peroxisome proliferator-activated receptor α, and carnitine palmitoyltransferase 1B in the liver, skeletal muscle, and subcutaneous adipose tissue, respectively. This indicates that dietary Cu may affect signaling pathways associated with lipid metabolism by improving the uptake, transport, and utilization of fatty acids. In conclusion, supplementation of copper hydroxychloride to the control diet improved growth performance and upregulated the abundance of some genes involved in postabsorptive metabolism of lipids.

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.

Advances in the mechanism of high copper diets in restraining pigs growth

High copper feed has been widely used as an inexpensive and highly effective feed additive to promote growth performance of pigs. However, long-term feeding of high copper feed may reduce the growth-promoting effects of copper, time-dependent accumulation of copper in animal tissues and organs, and copper toxicity thereby reducing the growth performance of pigs. Due to the widespread effects of high copper supplementation in animals' diets, the benefits and drawbacks of high copper feeding in pigs have been reported in several studies. Meanwhile, few of these studies have systematically described the mechanism by which high copper diets restrain pig growth. Therefore, to address the concerns and give a better understanding of the mechanism of high copper diet in restraining pig growth in different systems, this paper reviews the research progress of long-term supplementation of high copper on the growth of pigs and provides some suggestions and further research directions.

The effects of vaccination with keyhole limpet hemocyanin or oral administration of Salmonella enterica serovar Enteritidis on the growth performance of immunoglobulin knockout chickens

The nutritional cost of activating B cell-mediated immunity is thought to be low in chickens. However, this assumption is incompletely characterized. Immunoglobulin knockout (Ig-KO) chickens lacking B cells and immunoglobulin may potentially be a robust model to investigate the nutritional cost of immunity. Specifically, comparing the growth of Ig-KO chickens to immunocompetent birds (WT) following activation of the immune system should indicate costs associated with B cell-mediated immunity. A total of 3 experiments were conducted to determine if (1) an antibody response to keyhole limpet hemocyanin (KLH), (2) an intra-abdominal injection with Salmonella enterica serovar Enteritidis (SE), or (3) an oral challenge of SE would affect body weight gain (BWG) in homozygous Ig-KO (KO) chickens and their immunocompetent counterparts. In Experiment 1, a significant genotype*vaccination status interaction was observed (P = 0.03) during the period from 0 to 6 D after initial vaccination in which KLH injection reduced BWG in WT birds, but not in KO birds. A genotype*vaccination status interaction was present (P = 0.002) from 0 to 7 D after the first booster in which KLH injection due to reduced BWG in KO birds, but not WT birds. In Experiment 2, both KO and immunocompetent birds lost body weight during the period from 0 to 2 D after the SE injection, with no significant differences due to genotype (P = 0.92). Experiment 3 demonstrated that KO birds gained less weight than immunocompetent birds, with a tendency for less weight gain after an initial challenge (P = 0.07) and significantly so after a secondary challenge (P = 0.03). The results from these experiments collectively demonstrate that B cell-mediated immunity can affect growth performance in chickens. Furthermore, these effects can either preserve or impair growth performance, likely via mechanisms related to the immune response rather than the discrete nutritional cost of B cell-mediated immunity.

Suhuai suckling piglet hindgut microbiome-metabolome responses to different dietary copper levels

Unabsorbed copper accumulates in the hindgut of pigs that consume high levels of dietary copper, which enhances the coselection of antibiotic-resistant bacteria and is considered detrimental to the environment and to porcine health. In our study, a combination of 16S rRNA pyrosequencing and nontargeted metabolomics was used to investigate the microbiome-metabolome responses to dietary copper levels in the hindgut of suckling piglets. The results showed that the dietary copper level affected the abundance of several Clostridia genera and that the relative abundance of butyrate-producing bacteria, such as Coprococcus, Roseburia, and Acidaminococcus, was reduced in the 300 mg kg⁻¹ (high) Cu group. Metabolomic analysis revealed that dietary copper levels affected protein and carbohydrate metabolites, protein biosynthesis, the urea cycle, galactose metabolism, gluconeogenesis, and amino acid metabolism (including the metabolism of arginine, proline, β-alanine, phenylalanine, tyrosine, and methionine). Furthermore, Pearson’s correlation analysis showed that the abundance levels of Coprococcus (family Lachnospiraceae) and operational taxonomic unit (OTU) 18 (family Ruminococcaceae) were positively correlated with energy metabolism pathways (gluconeogenesis, glycolysis, and the pentose phosphate pathway). The abundance of Streptococcus was negatively correlated with amino acid metabolism pathways (protein biosynthesis, glycine, serine, threonine, methionine, phenylalanine, and tyrosine metabolism), and OTU583 and OTU1067 (family Rikenellaceae) were positively correlated with amino acid metabolism pathways. These results suggest that the copper levels consumed by LC (low-copper group) versus HC (high-copper group) animals alter the composition of the gut microbiota and modulate microbial metabolic pathways, which may further affect the health of suckling piglets.

Non-antibiotic feed additives in diets for pigs: A review

A number of feed additives are marketed to assist in boosting the pigs' immune system, regulate gut microbiota, and reduce negative impacts of weaning and other environmental challenges. The most commonly used feed additives include acidifiers, zinc and copper, prebiotics, direct-fed microbials, yeast products, nucleotides, and plant extracts. Inclusion of pharmacological levels of zinc and copper, certain acidifiers, and several plant extracts have been reported to result in improved pig performance or improved immune function of pigs. It is also possible that use of prebiotics, direct-fed microbials, yeast, and nucleotides may have positive impacts on pig performance, but results have been less consistent and there is a need for more research in this area.

Copper/zinc-loaded montmorillonite influences intestinal integrity, the expression of genes associated with inflammation, TLR4-MyD88 and TGF-β1 signaling pathways in weaned pigs after LPS challenge

This study was aimed at investigating whether dietary copper/zinc-loaded montmorillonite (Cu/Zn-Mt) could alleviate Escherichia coli LPS-induced intestinal injury through pro- and anti-inflammatory signaling pathways (TLRs, NLRs and TGF-β1) in weaned piglets. Eighteen 21-d-old pigs were randomly divided into three groups (control, LPS and LPS + Cu/Zn-Mt). After 21 d of feeding, pigs in the LPS group and LPS + Cu/Zn-Mt group received i.p. administration of LPS, whereas pigs in the control group received saline. At 4 h post-injection, jejunum samples were collected for analysis. The results indicated that, compared with the LPS group, supplemental Cu/Zn-Mt increased transepithelial electrical resistance, the expressions of anti-inflammatory cytokines (TGF-β1) in mRNA and protein levels, and decreased FD4 and the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-6, IL-8 and IL-1β). The pro-inflammatory signaling pathways results demonstrated that Cu/Zn-Mt supplementation decreased the mRNA levels of TLR4 and its downstream signals (MyD88, IRAK1, TRAF6) but had no effect on NOD1 and NOD2 signals. Cu/Zn-Mt supplementation did not affect NF-κB p65 mRNA abundance, but down-regulated its protein expression. The anti-inflammatory signaling pathways results showed supplemental Cu/Zn-Mt also increased TβRII, Smad4 and Smad7 mRNA expressions. These findings suggested dietary Cu/Zn-Mt attenuated LPS-induced intestinal injury by alleviating intestinal inflammation, influencing TLR4-MyD88 and TGF-β1 signaling pathways in weaned pig.

Effect of dietary copper level on the gut microbiota and its correlation with serum inflammatory cytokines in Sprague-Dawley rats

In China's swine industry, copper is generally supplemented above the National Research Council (NRC) requirement (2012) because of its antimicrobial properties and the potential for growth promotion. Yet few are concerned about whether this excess supplementation is necessary. In this study, the 16S rRNA pyrosequencing was designed and used to investigate the effect of dietary copper level on the diversity of the fecal microbial community and the correlation of copper level with the serum level of inflammatory cytokines in Sprague-Dawley rat models. The results showed that the diet containing a high level of Cu (120 and 240 mg/kg) changed the microbial richness and diversity of rat feces associated with the increased copper content in the rat ileac and colonic digesta. Furthermore, a Pearson's correlation analysis indicated that an accumulation of unabsorbed copper in the chyme was correlated with the microbial composition of the rat feces, which was linked with TNF-α in serum. The results suggest that dietary copper level may have a direct impact on circulating inflammatory cytokines in the serum, perhaps inducing an inflammatory response by altering the microbial composition of rat feces. Serum TNF-α could be the chief responder to excessive copper exposure.

Feed supplementation with arginine and zinc on antioxidant status and inflammatory response in challenged weanling piglets

Although supplementing the diet with zinc oxide and arginine is known to improve growth in weanling piglets, the mechanism of action is not well understood. We measured the antioxidant status and inflammatory response in 48 weanling castrated male piglets fed diets supplemented with or without zinc oxide (2,500 mg Zn oxide per kg) and arginine (1%) starting at the age of 20 days. The animals were injected with lipopolysaccharide (100 μg/kg) on day 5. Half of them received another injection on day 12. Blood samples were taken just before and 6, 24 and 48 h after injection and the mucosa lining the ileum was recovered following euthanizing on days 7 and 14. Zinc supplementation increased reduced and total glutathione (GSH) (reduced and total) during days 5 to 7 and arginine decreased oxidized GSH measured on days 5 and 12 and the ratio of total antioxidant capacity to total oxidative status during days 12 to 14. Zinc decreased plasma malondialdehyde measured on days 5 and 12 and serum haptoglobin measured on day 12 and increased both metallothionein-1 expression and total antioxidant capacity measured in the ileal mucosa on day 14. Tumour necrosis factor α concentration decreased from days 5 to 12 (all effects were significant at P < 0.05). This study shows that the zinc supplement reduced lipid oxidation and lipopolysaccharide-induced inflammation during the post-weaning period, while the arginine supplementation had only a limited effect.

Effects of subchronic oral toxic metal exposure on the intestinal microbiota of mice

Oral exposure to toxic metals such as cadmium (Cd), lead (Pb), copper (Cu) and aluminum (Al) can induce various adverse health effects in humans and animals. However, the effects of these metals on the gut microbiota have received limited attention. The present study demonstrated that long-term toxic metal exposure altered the intestinal microbiota of mice in a metal-specific and time-dependent manner. Subchronic oral Cu exposure for eight weeks caused a profound decline in gut microbial diversity in mice, whereas no significant changes were observed in groups treated with other metals. Cd exposure significantly increased the relative abundances of organisms from the genera Alistipes and Odoribacter and caused marked decreases in Mollicutes and unclassified Ruminococcaceae. Pb exposure significantly decreased the abundances of eight genera: unclassified and uncultured Ruminococcaceae, unclassified Lachnospiraceae, Ruminiclostridium_9, Rikenellaceae_RC9_gut_group, Oscillibacter, Anaerotruncus and Lachnoclostridium. Cu exposure affected abundances of the genera Alistipes, Bacteroides, Ruminococcaceae_UCG-014, Allobaculum, Mollicutes_RF9_norank, Rikenellaceae_RC9_gut_group, Ruminococcaceae_unclassified and Turicibacter. Al exposure increased the abundance of Odoribacter and decreased that of Anaerotruncus. Exposure to any metal for eight weeks significantly decreased the abundance of Akkermansia. These results provide a new understanding regarding the role of toxic metals in the pathogenesis of intestinal and systemic disorders in the host within the gut microbiota framework.

Dietary High Zinc Oxide Modulates the Microbiome of Ileum and Colon in Weaned Piglets

Dietary zinc oxide (ZnO) at pharmacological level has been widely used to prevent and treat diarrhea in weaning piglets. Despite its importance for promoting animal health and performance, the influence of microbiome profiles in intestinal tracts by ZnO needs to be comprehensively investigated. In this study, we conducted a comparative microbial community analysis in the ileum and colon of piglets fed by either control diet, high ZnO (3,000 mg/kg) supplement or antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) supplement. Our results showed that both high dietary ZnO and in-feed antibiotics supplementations significantly increased 5 phyla of Spirochaetes, Tenericutes, Euryarchaeota, Verrucomicrobia, TM7, and reduced 1 phyla of Chlamydiae in ileal digesta. The relative abundance of opportunistic pathogens Campylobacterales were decreased while Enterobacteriales were increased in ZnO or antibiotics-supplemented group when compared to the control. In the colon, the phyla Euryarchaeota, the genus Methanobrevibacter, and the species Methanobrevibacter smithii were drastically increased by high dietary ZnO supplementation when compared with other groups. The microbial functional prediction analysis showed that high dietary ZnO and in-feed antibiotics had a higher abundance of transporter pathway enrichment in the ileum when compared with the control. While in the colon high dietary ZnO had a higher abundant enrichment of methane metabolism involving energy supply when compared with other groups. Both high dietary ZnO and antibiotics increased the microbiota diversity of ileal digesta while they decreased the microbiota diversity of the colonic digesta. Collectively, these results suggested that dietary ZnO and in-feed antibiotics supplementations presented similar effect on ileal microbiota, and mainly affected the non-predominant microbiota.

In vitro Solubility of Copper(II) Sulfate and Dicopper Chloride Trihydroxide for Pigs

This study was conducted to determine the solubility of copper (Cu) in two sources of copper(II) sulfate (CuSO₄) including monohydrate and pentahydrate and three sources of dicopper chloride trihydroxide (dCCTH) including α-form (dCCTH-α), β-form (dCCTH-β), and a mixture of α- and β-form (dCCTH-αβ) at different pH and a 3-step in vitro digestion assay for pigs. In Exp. 1, Cu sources were incubated in water-based buffers at pH 2.0, 3.0, 4.8, and 6.8 for 4 h using a shaking incubator at 39°C. The CuSO₄ sources were completely dissolved within 15 min except at pH 6.8. The solubility of Cu in dCCTH-α was greater (p<0.05) than dCCTH-β but was not different from dCCTH-αβ during 3-h incubation at pH 2.0 and during 2-h incubation at pH 3.0. At pH 4.8, there were no significant differences in solubility of Cu in dCCTH sources. Copper in dCCTH sources were non-soluble at pH 6.8. In Exp. 2, the solubility of Cu was determined during the 3-step in vitro digestion assay for pigs. All sources of Cu were completely dissolved in step 1 which simulated digestion in the stomach. In Exp. 3, the solubility of Cu in experimental diets including a control diet and diets containing 250 mg/kg of additional Cu from five Cu sources was determined during the in vitro digestion assay. The solubility of Cu in diets containing additional Cu sources were greater (p<0.05) than the control diet in step 1. In conclusion, the solubility of Cu was influenced by pH of digesta but was not different among sources based on the in vitro digestion assay.

Effect of dietary copper amount and source on copper metabolism and oxidative stress of weanling pigs in short-term feeding

Forty-eight weanling barrows were used to determine the effects of amount and source of dietary Cu on Cu metabolism, oxidative stress in the duodenum, and VFA ratios in the cecum of weanling pigs in short-term feeding. At 21 d of age, newly weaned pigs were stratified by BW (7.03 ± 1.20 kg) and equally assigned to 1 of the following dietary treatments: 1) control (5 mg supplemental Cu/kg diet from CuSO4), 2) 225 mg supplemental Cu/kg diet from CuSO4, or 3) 225 mg supplemental Cu/kg diet from tribasic Cu chloride (TBCC). Pigs were housed 2 pigs per pen and were fed a complex diet until harvest on d 11 and 12. During harvest, bile and liver were obtained for mineral analysis, and liver samples were obtained for analysis of mRNA expression of Cu regulatory proteins. Digesta of duodenum, proximal jejunum, and ileum were collected for soluble Cu analysis. Mucosal scrapings of duodenum, proximal jejunum, and ileum were obtained for analysis of mucosal Cu concentration and mRNA expression of Cu regulatory proteins. Duodenal mucosal scrapings were also collected for analysis of malondialdehyde (MDA). Pigs fed high Cu had markedly greater (P < 0.0001) Cu concentrations in the duodenal, proximal jejunal, and ileal mucosa than controls. Copper in the duodenal mucosa was greater (P = 0.003) in CuSO4 than TBCC pigs. Duodenal MDA concentrations were greater (P = 0.003) in CuSO4 vs. control pigs and tended (P = 0.06) to be greater than in TBCC pigs. Duodenal antioxidant 1 (Atox1) mRNA was downregulated (P < 0.01) in pigs fed high Cu compared to controls and was not affected by Cu source. Compared with control pigs, those fed CuSO4 and TBCC had greater (P < 0.001) liver and bile Cu concentrations. Liver Cu was also greater (P = 0.0007) in TBCC than CuSO4-fed pigs. Hepatic Cu transporting β-polypeptide ATPase (Atp7b) was upregulated (P = 0.02) in the Cu-supplemented pigs compared with controls and did not differ among Cu sources. The acetate:propionate ratio in cecal contents was much greater in pigs supplemented with 225 mg Cu/kg diet than in controls. When fed at 225 mg Cu/kg diet, TBCC may cause less oxidative stress in the duodenum than CuSO4. Feeding weanling pigs increased Cu resulted in modulation of duodenal and liver at the transcription level.

Antimicrobial use in swine production and its effect on the swine gut microbiota and antimicrobial resistance

Antimicrobials have been used in swine production at subtherapeutic levels since the early 1950s to increase feed efficiency and promote growth. In North America, a number of antimicrobials are available for use in swine. However, the continuous administration of subtherapeutic, low concentrations of antimicrobials to pigs also provides selective pressure for antimicrobial-resistant bacteria and resistance determinants. For this reason, subtherapeutic antimicrobial use in livestock remains a source of controversy and concern. The swine gut microbiota demonstrates a number of changes in response to antimicrobial administration depending on the dosage, duration of treatment, age of the pigs, and gut location that is sampled. Both culture-independent and -dependent studies have also shown that the swine gut microbiota contains a large number of antimicrobial resistance determinants even in the absence of antimicrobial exposure. Heavy metals, such as zinc and copper, which are often added at relatively high doses to swine feed, may also play a role in maintaining antimicrobial resistance and in the stability of the swine gut microbiota. This review focuses on the use of antimicrobials in swine production, with an emphasis on the North American regulatory context, and their effect on the swine gut microbiota and on antimicrobial resistance determinants in the gut microbiota.

Long-term dietary pattern of fecal donor correlates with butyrate production and markers of protein fermentation during in vitro fecal fermentation

Diet influences gut microbiota composition. Therefore, we hypothesized that diet would impact the extent of dietary fiber utilization and the types of metabolic end-products produced by the microbiota during in vitro fecal fermentation. By obtaining long-term dietary records from fecal donors, we aimed to determine the correlations between dietary intake variables and dietary fiber degradation and short-/branched-chain fatty acid (BCFA) and ammonia production during in vitro fecal fermentation. Eighteen subjects completed 1-year diet history questionnaires and provided fecal samples that were used for in vitro fermentation of a whole wheat substrate. The percentage of dietary fiber fermented was not correlated with nutrient intakes; however, butyrate production was correlated with fecal donor intake of many nutrients of which principal component analysis revealed were mostly contributed by grain-, nut-, and vegetable-based foods. Negative correlations were found for propionate with intake of total carbohydrate, added sugar, and sucrose and for ammonia and BCFA production with intake of unsaturated fats. Thus, our analysis did not support our first hypothesis: the percentage of dietary fiber fermented during in vitro fermentation was not correlated with dietary records. However, production of butyrate; BCFA; ammonia; and, to a lesser extent, propionate was correlated with the diet records of fecal donors, thus supporting our second hypothesis. These results suggest that diets high in plant-based foods and high in unsaturated fats are associated with microbial metabolism that is consistent with host health.

Antioxidant status and inflammatory response in weanling piglets fed diets supplemented with arginine and zinc

Bergeron, N., Robert, C. and Guay, F. 2014. Antioxidant status and inflammatory response in weanling piglets fed diets supplemented with arginine and zinc. Can. J. Anim. Sci. 94: 87–97. Dietary supplementation with zinc oxide (Zn oxide) and arginine (Arg) is known to improve growth in weanling piglets. The mechanism of action is not yet well understood, although antioxidant effects and inflammatory responses may be involved. This experiment was conducted to evaluate the effects of Zn and Arg supplementation on the antioxidant status and inflammatory response of piglets. Thirty-two 20-d-old weanling piglets were placed for 12 d on diets supplemented or not with Zn (2500 mg Zn oxide kg−1) and Arg (1%), designated ZN0ARG0, ZN2500ARG0, ZN0ARG1 and ZN2500ARG1. On day 12, blood samples were taken before and 3 h after intra-peritoneal injection of lipopolysaccharide (LPS; 10 µg kg−1). The piglets were euthanized just after the second blood sample, and samples of mucosae were taken from the jejunum and ileum for determination of mRNA expression and morphological observation. Zn supplementation decreased plasma malondialdehyde measured before LPS injection (P<0.05). Arg supplementation increased the ferric-reducing ability of plasma (indicator of antioxidant status) measured after LPS injection (P<0.05). Piglets fed Zn-supplemented diets had lower total plasma superoxide-dismutase (SOD) activity (P<0.05) but higher plasma tumour necrosis factor-α (P<0.05) after LPS injection. Zinc-supplemented diets increased metallothionein-1 expression and total antioxidant capacity in the ileum and jejunum (P<0.05) and decreased interleukin-10 expression (P<0.05) in the ileum. In the jejunum, the combination of Zn and Arg supplementation increased villus height (Arg×Zn, P<0.05). These results indicate that Zn may reduce systemic oxidation and improve the antioxidant status in the jejunal and ileal mucosae. However, Zn and Arg supplementation did not appear to act synergistically to enhance antioxidant status or reduce inflammation in weanling piglets.

Additivity of effects from dietary copper and zinc on growth performance and fecal microbiota of pigs after weaning

Four experiments were conducted to determine the interactive effects of pharmacological amounts of Zn from ZnO and Cu from organic (Cu-AA complex; Cu-AA) or inorganic (CuSO(4)) sources on growth performance of weanling pigs. The Cu was fed for 4 (Exp. 1) or 6 (Exp. 2, 3, and 4) wk after weaning, and Zn was fed for 4 (Exp. 1) or 2 (Exp. 2, 3, and 4) wk after weaning. Treatments were replicated with 7 pens of 5 or 6 pigs per pen (19.0 ± 1.4 d of age and 5.8 ± 0.4 kg of BW, Exp. 1), 12 pens of 21 pigs per pen (about 21 d of age and 5.3 kg of BW, Exp. 2), 5 pens of 4 pigs per pen (20.3 ± 0.5 d of age and 7.0 ± 0.5 kg of BW, Exp. 3), and 16 pens of 21 pigs per pen (about 21 d of age and 5.7 kg of BW, Exp. 4). In Exp. 1 and 2, Cu-AA (0 vs. 100 mg/kg of Cu) and ZnO (0 vs. 3,000 mg/kg of Zn) were used in a 2 × 2 factorial arrangement. Only Exp. 1 used in-feed antibiotic (165 mg of oxytetracycline and 116 mg of neomycin per kilogram feed), and Exp. 2 was conducted at a commercial farm. In Exp. 3, sources of Cu (none; CuSO(4) at 250 mg/kg of Cu; and Cu-AA at 100 mg/kg of Cu) and ZnO (0 vs. 3,000 mg/kg of Zn) were used in a 3 × 2 factorial arrangement. In Exp. 4, treatments were no additional Cu, CuSO(4) at 315 mg/kg of Cu, or Cu-AA at 100 mg/kg of Cu to a diet supplemented with 3,000 mg/kg of Zn from ZnO and in-feed antibiotic (55 mg of carbadox per kilogram of feed). In Exp. 1 and 2, both Zn and Cu-AA improved (P < 0.001 to P = 0.03) ADG and ADFI. No interactions were observed, except in wk 1 of Exp. 2, where Zn increased the G:F only in the absence of Cu-AA (Cu-AA × Zn, P = 0.04). A naturally occurring colibacillosis diarrhea outbreak occurred during this experiment. The ZnO addition reduced (P < 0.001) the number of pigs removed and pig-days on antibiotic therapy. In Exp 3, ADFI in wk 2 was improved by Zn and Cu (P < 0.001 and P = 0.09, respectively) with no interactions. In wk 1, G:F was reduced by ZnO only in the absence of Cu (Cu × Zn, P = 0.03). Feeding Zn decreased fecal microbiota diversity in the presence of CuSO(4) but increased it in the presence of Cu-AA (Cu source × Zn, P = 0.06). In Exp. 4, Cu supplementation improved the overall ADG (P = 0.002) and G:F (P < 0.001). The CuSO(4) effect on G:F was greater (P < 0.001) than the Cu-AA effect. Our results indicate that pharmacological amounts of ZnO and Cu (Cu-AA or CuSO(4)) are additive in promoting growth of pigs after weaning.

Supplementation of diets for lactating sows with zinc amino acid complex and gastric nutriment-intubation of suckling pigs with zinc methionine on mineral status, intestinal morphology and bacterial translocation in lipopolysaccharide-challenged weaned pigs

Sixty-four pigs from 16 sows were used to evaluate addition of zinc amino acid complex (ZnAA) to lactating sows and gastric nutriment-intubation of zinc methionine (ZnMet) to suckling pigs on mineral status, intestinal morphology and bacterial translocation after weaning. Sows were fed a barley-based diet supplying 120 ppm zinc (Zn; control) or the control diet supplemented with 240 ppm Zn from ZnAA. At birth, day-10 and day-21 (weaning) of age, pigs from each litter were nutriment-intubated with 5 ml of an electrolyte solution without or with 40 mg Zn from ZnMet. At weaning, 24 h prior to the collection of small and large intestinal lymph nodes and sections of the duodenum, jejunum and ileum, the pigs received an intramuscular injection of saline without or with 150 microg/kg body weight of Escherichia coli O26:B6 lipopolysaccharide (LPS). With the exception of a tendency (p = 0.09) for lower serum concentration of copper in pigs at weaning from ZnAA-supplemented sows, there were no differences (p > 0.1) than for pigs from control-fed sows for mineral status or intestinal morphology. Nutriment-intubation of ZnMet increased serum (p = 0.001) and liver (p = 0.003) Zn concentrations, number of goblet cells per 250 microm length of jejunal villous epithelium (p = 0.001) and tended (p = 0.06) to enhance jejunum mucosa thickness. Interactive effects (p < 0.05) for higher jejunal villi height and villi:crypt ratio and increased ileal goblet cell counts were apparent for pigs from ZnAA-supplemented sows that also received nutriment-intubation of ZnMet. Challenge with LPS increased (p = 0.05) ileal villous width. Nutriment-intubation of ZnMet decreased (p = 0.05) anaerobic bacteria colony forming unit counts in the large intestinal mesenteric lymph nodes. In conclusion, nutriment-intubation of ZnMet increased serum and liver tissue concentrations of Zn and resulted in limited improvement to intestinal morphology of weaned pigs.

Supplementation of diets for gestating sows with zinc amino acid complex and gastric intubation of suckling pigs with zinc-methionine on mineral status, intestinal morphology and bacterial translocation in lipopolysaccharide-challenged early-weaned pigs

Eighty male pigs from 20 litters were used to evaluate dietary addition of 250mg/kg of Zn from zinc amino acid complex (ZnAA) to sows during the last trimester of gestation and gastric intubation of 40mg Zn from soluble zinc methionine (ZnMet) to suckling pigs at birth and on day 7 and 14 (weaning) on small intestinal morphology, Zn status and bacterial translocation in early-weaned pigs. At weaning, pigs were challenged with an intramuscular injection of saline without or with 120microg/kg BW of lipopolysaccharide (LPS; from Escherichia coli O26:B6) and were euthanized 24h later prior to collection of intestinal lymph nodes and small intestinal sections. Zinc concentration in serum 7 days after birth and at weaning were higher in pigs from ZnAA-supplemented sows and those receiving gastric intubation with ZnMet (P=0.05 and P<0.0001, respectively). Post-weaning liver tissue concentrations for Zn (P<0.0001) and Fe (P=0.04) were higher and for Cu lower (P<0.0001) in pigs intubated with ZnMet. Pigs from ZnAA-supplemented compared with control-fed sows tended (P<0.1) to have increased villi height and villus:crypt ratio in the jejunum and higher (P=0.1) goblet cell counts in the ileum. Goblet cell counts of ZnMet-intubated (P=0.03) and LPS-challenged pigs (P=0.05) were also higher in the jejunum. Supplementation of ZnAA to gestating sows increased (P=0.04) E. coli colony forming unit counts in the small intestinal mesenteric lymph nodes of early-weaned pigs. In conclusion, dietary addition of ZnAA to gestating sows and gastric intubation of ZnMet improved Zn status of suckling pigs.

Effects of dietary supplementation with an expressed fusion peptide bovine lactoferricin–lactoferrampin on performance, immune function and intestinal mucosal morphology in piglets weaned at age 21 d

Lactoferrin has antimicrobial activity associated with peptide fragments lactoferricin (LFC) and lactoferrampin (LFA) released on digestion. These two fragments have been expressed inPhotorhabdus luminescensas a fusion peptide linked to protein cipB. The construct cipB–LFC–LFA was tested as an alternative to antimicrobial growth promoters in pig production. Sixty piglets with an average live body weight of 5·42 (sem0·59) kg were challenged with enterotoxigenicEscherichia coliand randomly assigned to four treatment groups fed a maize–soyabean meal diet containing either no addition (C), cipB at 100 mg/kg (C+B), cipB–LFC–LFA at 100 mg/kg (C+L) or colistin sulfate at 100 mg/kg (C+CS) for 3 weeks. Compared with C, dietary supplementation with C+L for 3 weeks increased daily weight gain by 21 %, increased recovery from diarrhoea, enhanced serum glutathione peroxidase (GPx), peroxidase (POD) and total antioxidant content (T-AOC), liver GPx, POD, superoxide dismutase and T-AOC, Fe, total Fe-binding capacity, IgA, IgG and IgM levels (P < 0·05), decreased the concentration ofE. coliin the ileum, caecum and colon (P < 0·05), increased the concentration of lactobacilli and bifidobacteria in the ileum, caecum and colon (P < 0·05), and promoted development of the villus–crypt architecture of the small intestine. Growth performance was similar between C+L- and C+CS-supplemented pigs. The present results indicate that LFC–LFA is an effective alternative to the feed antibiotic CS for enhancing growth performance in piglets weaned at age 21 d.