Influence of dietary zinc and copper on digestive enzyme activity and intestinal morphology in weaned pigs1

Use of nanotechnology-based nanomaterial as a substitute for antibiotics in monogastric animals

Nanotechnology has emerged as a promising solution for tackling antibiotic resistance in monogastric animals, providing innovative methods to enhance animal health and well-being. This review explores the novel use of nanotechnology-based nanomaterials as substitutes for antibiotics in monogastric animals. With growing global concerns about antibiotic resistance and the need for sustainable practices in animal husbandry, nanotechnology offers a compelling avenue to address these challenges. The objectives of this review are to find out the potential of nanomaterials in improving animal health while reducing reliance on conventional antibiotics. We examine various forms of nanomaterials and their roles in promoting gut health and also emphasize fresh perspectives brought by integrating nanotechnology into animal healthcare. Additionally, we delve into the mechanisms underlying the antibacterial properties of nanomaterials and their effectiveness in combating microbial resistance. By shedding light on the transformative role of nanotechnology in animal production systems. This review contributes to our understanding of how nanotechnology can provide safer and more sustainable alternatives to antibiotics.

Effects of organic trace minerals chelated with oligosaccharides on growth performance, blood parameters, slaughter performance and meat quality in sheep

The present study assessed the effects of oligosaccharide-chelated organic trace minerals (OTM) on the growth performance, digestive enzyme activity, blood parameters, slaughter performance, and meat quality indexes of mutton sheep. A total of 60 East Ujumuqin × small-tailed Han crossbred mutton sheep were assigned to two groups (10 duplicates per group) by body weight (26.12 ± 3.22 kg) according to a completely randomized design. Compared to the CON group, the results of the OTM group showed: (1) no significant changes in the initial body weight, final body weight, dry matter intake, average daily gain, and feed conversion ratio (p > 0.05); (2) the activities of trypsin, lipase, and amylase in the jejunum were significantly increased (p < 0.05); (3) serum total protein, albumin, and globulin of the blood were significantly increased (p < 0.05), and the growth factor interleukin IL-10 was significantly higher (p < 0.05), while IL-2, IL-6, and γ-interferon were significantly lower (p < 0.05). Immunoglobulins A, M, and G were significantly higher (p < 0.05); (4) the live weight before slaughter, carcass weights, dressing percentage, eye muscle areas, and GR values did not differ significantly (p > 0.05); (5) shear force of mutton was significantly lower (p < 0.05), while the pH45min, pH24h, drip loss, and cooking loss did not show a significant difference (p > 0.05). The content of crude protein was significantly higher (p < 0.05), while the ether extract content was significantly reduced (p < 0.05), but no significant difference was detected between moisture and ash content; (6) the total amino acids, essential amino acids, semi-essential amino acids, and umami amino acids were significantly increased (p < 0.05). Although umami amino acids were not significant, the total volume increased (p > 0.05). Among these, the essential amino acids, threonine, valine, leucine, lysine in essential amino acids and arginine were significantly increased (p < 0.05). Also, non-essential amino acids, glycine, serine, proline, tyrosine, cysteine, and aspartic acid, were significantly higher (p < 0.05). The content of alanine, aspartate, glutamic acid, phenylalanine, and tyrosine in umami amino acids was significantly higher (p < 0.05).

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.

Enhancement of protective vaccine-induced antibody titer to swine diseases and growth performance by Amino-Zn, yucca extract, and β-mannanase feed additive in wean-finishing pigs

The primary purpose of this research is to determine the effect of Amino-Zn (AZn), Yucca schidigera extract (YE), and β-mannanase enzyme supplementation on growth performance, nutrient digestibility, fecal gas emission, and immune response in pigs. A total of 180 crossbred pigs (6.57 ± 1 kg) were randomly assigned to one of three dietary treatments: CON-corn soybean meal (basal diet); TRT1-CON +1,000 ppm AZn + 0.07% yucca extract (YE) + 0.05% β-mannanase; and TRT2-CON +2,000 ppm AZn + 0.07% YE+ 0.05% β-mannanase for 22 weeks. Each treatment had 12 replicates with 5 pigs per pen. Pigs fed a diet supplemented with AZn, YE, and β-mannanase linearly increased (p < 0.05) BW and average daily gain at weeks 6, 12, 17, and 18. In contrast, the gain-to-feed ratio showed a linear increase (p < 0.05) from weeks 6 to 17 and the overall trial period. Moreover, the inclusion of experimental diets linearly decreased (p > 0.05) noxious gas emissions such as ammonia, hydrogen sulfide, acetic acid, carbon dioxide, and methyl mercaptans. The dietary inclusion of AZn, YE, and β-mannanase significantly increased the serological immune responses to Mycoplasma hyopneumoniae (MH) and foot-and-mouth disease virus (FMDV-O type) at the end of week 6 and porcine circovirus-2 (PCV-2) at week 19. Based on this result, we infer that the combination of AZn, YE, and β-mannanase supplement would serve as a novel in-feed additive to enhance growth performance and act as a boosting agent and immune stimulatory to increase the efficacy of swine vaccinations.

Risk factors associated with post-weaning diarrhoea in Austrian piglet-producing farms

Post-weaning diarrhoea (PWD) is a frequent, multifactorial disease of piglets leading to increased mortality rates and high economic losses. Due to the emergence of multi-resistant Escherichia coli isolates and the ban of zinc oxide (ZnO) in the EU since June 2022, alternative measures to prevent PWD are urgently needed. While an abundance of feed supplements is described to prevent PWD, there are hardly any studies reflecting the current situation of PWD in the field. Thus, we aimed to identify differences in management practices, housing and feeding strategies between farms with PWD and farms without PWD. Data were personally collected using a semi-structured questionnaire in 257 Austrian piglet-producing farms. Farms with PWD in more than 10% of all weaned groups within twelve months prior to data collection were defined as case farms (n = 101), while the remaining 136 farms were defined as control farms. Data from 237 farms and 69 explanatory variables were analysed via penalized binary logistic regression using elastic-net in 100 different splits into randomly selected training and test datasets (80:20). Treatment with ZnO and/or colistin (136 farms) was negatively associated with PWD in all splits and had the biggest estimated absolute log odds ratio out of all tested variables. Implementation of an all-in/all-out system in the nursery units and administration of probiotics or horseradish also had preventive effects in most splits (≥ 97%). A higher number of feeding phases for piglets within the first seven weeks of life and housing on fully slatted floors was associated negatively with the occurrence of PWD as well in > 95% of all splits. PWD was more likely to occur on farms having problems with neonatal diarrhoea or postpartum dysgalactia syndrome. While our data demonstrate that treatment with ZnO or colistin had the biggest statistical effect on PWD, we were able to identify other preventive measures like supplementation with probiotics or horseradish. Since implementation of all-in/all-out measures and fully slatted floors were also negatively associated with the occurrence of PWD on visited farms, we assume that reduction of bacterial load by the implementation of simple hygiene measures are still crucial to prevent PWD.

An alternative ZnO with large specific surface area: Preparation, physicochemical characterization and effects on growth performance, diarrhea, zinc metabolism and gut barrier function of weaning piglets

High-dose ZnO is widely used to prevent diarrhea and promote growth of weaning piglets, which has led to serious problems of animal toxicity, bacterial resistance and environmental pollution. In this study, a novel alternative ZnO (AZO) was prepared and its physicochemical properties were characterized. Animal experiments were further conducted to evaluate the effects of the ZnO forms, the dose of AZO and the combinations with AZO on the growth performance, diarrhea, zinc metabolism and gut barrier function of weaning piglets. The results showed that the AZO, compared with ordinary ZnO (OZO), nano ZnO (NZO) and porous ZnO (PZO), had the largest surface area and reduced the release of Zn²⁺ into the gastric fluid. AZO showed better antibacterial activity on Escherichia coli K88, Staphylococcus aureus and Salmonella enteritidis but lower cytotoxicity on porcine intestinal epithelial cells. Animal experiments suggested that low-dose AZO, NZO and PZO (300 mg/kg) improved growth performance and reduced diarrhea in weaning piglets as well as high-dose OZO (3000 mg/kg). Notably, low-dose AZO had the lowest diarrhea incidence. Additionally, low-dose AZO in combination with probiotics improved digestibility and digestive enzyme activities. Low-dose AZO in combination with probiotics also upregulated the expression of the intestinal zinc transporter proteins ZIP4 and DMT1, increased zinc bioavailability, reduced faecal zinc emissions, and avoided zinc overload in the liver and oxidative damage caused by high-dose ZnO. Moreover, low-dose AZO in combination with probiotics improved the gut barrier function of weaning piglets by promoting the expression of tight junction proteins, mucins and antimicrobial peptides and increasing gut microbiota diversity and beneficial Lactobacillus. This study proposed a novel strategy to replace high-dose ZnO and antibiotics with low-dose AZO and probiotics in weaning piglets, which effectively improved growth performance and prevented diarrhea while reducing animal toxicity, bacterial resistance, heavy metal residues and zinc emission pollution.

Determination of the optimal dietary zinc content for pigs between 10 and 30 kg body weight

The Zn requirement of pigs immediately after weaning is more investigated compared to the Zn requirement in the growth period between 10 and 30 kg. Unabsorbed and excessive dietary Zn is excreted mainly through feces, and spreading pig slurry to fields can cause environmental issues because high levels of Zn can impair plant growth and contribute to the development of antimicrobial resistance genes in microorganisms. Therefore, more precise knowledge of Zn requirements and dietary Zn recommendations is important. The present study investigated the optimal dietary Zn content for 10- to 30-kg pigs. The study used 150 pigs weaned at 28 d of age (day 0) and supplied with 1,474 mg dietary Zn/kg the first 2 wk post-weaning. After 2 wk, pigs were randomly distributed according to body weight (BW; 10.1 ± 0.3 kg) and sex, to individually housing, and fed a diet supplemented with either 0, 30, 60, 120, or 240 mg Zn/kg (from ZnO), resulting in total dietary Zn contents of 80, 92, 117, 189, and 318 mg/kg until week 6 post-weaning. BW, feed intake, and fecal scores were recorded, and samples of blood (weeks 2, 3, 5, and 6) and tissues (week 6) were collected. The feed intake, growth, feed efficiency, relative weight of the pancreas and liver, Zn concentration in the liver, and pancreatic digestive enzyme activity were unaffected by dietary Zn content (P > 0.12). The serum Zn level decreased (P < 0.01) by up to 24% from weeks 2 to 3. The serum Zn concentrations in weeks 5 and 6 were similar to in week 2 when 117, 189, and 318 mg Zn/kg were provided, while with 80 and 92 mg Zn/kg the serum Zn concentration was lower (P < 0.01) than in week 2. The serum Zn concentration reached a plateau in weeks 5 and 6, and breakpoints were calculated at 126 ± 17 and 102 ± 6 mg Zn/kg, respectively. Bone Zn status was greater (P < 0.01) with 189 than 80 mg Zn/kg and a breakpoint was calculated at 137 ± 19 mg Zn/kg. According to performance, the Zn requirement for 10- to 30-kg pigs can be fulfilled with 80 mg total Zn/kg, but based on serum and bone Zn status, the optimal total dietary Zn content is 102 to 137 mg/kg. The latter corresponds to a daily Zn intake (requirement) of 103 to 138 mg when calculated from the average feed intake during weeks 3 to 6 (1,005 g/d). Importantly, the presented results are obtained in pigs supplied with 1,474 mg Zn/kg from ZnO the first 2 wk post-weaning and a high level of phytase (1,000 phytase units) in the diet throughout the experiment.

Replacing ZnSO4 with Zn-glycine in the diet of goat promotes the pancreatic function of the offspring

Zinc supplementation in the diet of goats affects pancreas development in offspring. However, the impact of maternal inorganic and organic zinc supplementation in offspring is poorly defined. In this study, 14 late-pregnant goats were assigned at random to the zinc sulfate group (ZnSO₄, n = 7) and the zinc-glycine chelate group (Zn-Gly, n = 7), respectively. Serum samples and pancreas tissue were collected from kids whose mothers were fed ZnSO₄ and Zn-Gly at the late pregnancy, respectively. Histologic examination showed no morphologic differences between the 2 groups. Pancreatic zinc content in kids tended to be increased when replacing ZnSO₄ with Zn-Gly. The serum insulin concentration was greater and glucagon less in the Zn-Gly group when compared to the ZnSO₄ group. The activities of lipase and chymotrypsin were enhanced when replacing ZnSO₄ with Zn-Gly. Proteomics results showed that 234 proteins were differentially expressed between the 2 groups, some of which were associated with the secretion of insulin, enzyme activity and signal transduction. The results suggested that supply of dietary Zn-Gly to goats during late pregnancy promoted pancreatic function in offspring compared with dietary ZnSO₄ supplementation. This provides new information about pancreatic function when supplementing different zinc sources in the diets of late pregnant goats.

Effects of dietary copper sources and levels on growth performance, copper digestibility, fecal and serum mineral characteristics in growing pigs

This experiment was conducted to investigate the effects of three different copper (Cu) sources (one inorganic and two organics) and levels (0, 50, and 100 mg/kg) on the growth performance, Cu digestibility, fecal mineral excretion, serum mineral concentration, jejunal morphology, and serum biochemical profile of growing pigs. A total of 42 male, growing pigs (31.08 ± 1.82 kg) were randomly assigned to seven treatments consisting of one negative control (0 mg/kg of added Cu level) and treatments with copper sulfate (CuSO4), Cu-amino acid complex (CuAA), and Cu-hydroxy-4-methylthio butanoate chelate complex (CuHMB) at 50 and 100 mg/kg each for 28 d. Pigs fed 50 or 100 mg/kg of Cu showed improved (p < 0.05) average daily gain and feed intake. Although Cu excretion decreased (p < 0.01) in pigs fed 100 mg/kg of organic Cu sources compared to those fed CuSO₄, there was no difference between the Cu sources in pigs fed 50 mg/kg. However, the apparent total tract digestibility of Cu increased (p < 0.01) in pigs fed organic Cu sources compared with that in pigs fed CuSO₄. The addition of CuHMB increased (p < 0.01) serum phosphorus and sulfur concentrations; however, there were no effects of source and level on jejunal morphology and serum biochemical profile. These results suggest that the inclusion (50 mg/kg) of organic Cu sources (CuAA and CuHMB) in the growing pig diet could be beneficial for growth performance and Cu availability and may reduce environmental pollution.

Effect of Supplemental Zinc on Performance, Nutrient Digestibility, Jejunum Architecture, and Immune Response in Broiler chickens Fed Wheat-Soy Diets

The present study was conducted to evaluate the effect of dietary zinc (Zn) levels on growth performance, carcass characteristic, nutrient digestibility, jejunum architecture and immune responses in broiler chickens fed wheat-soy diets. In addition the Zn requirement to optimize responses were estimated through regression models. A total, of 250 day-old male Ross-308 broiler chicks were randomly allocated to a completely randomized design experiment with five dietary treatments of five replicates of 10 birds each. Birds were fed diets containing 30, 70, 110, 150, and 190 mg/kg Zn from 1 to 35 days of age. A Zn level of 70 mg/kg diet was adequate to acquire typical growth performance, the nutrient digestibility, and carcass yield. First antibody titres response to sheep red blood cell inoculation, cutaneous basophil hypersensitivity elicited by phytohemagglutinin-P intradermal injection increased linearly by the increase in dietary Zn level. The Zn requirement estimated by the quadratic and linear broken-line models was varied between 63-70 mg/kg to optimize growth performance criteria. It is concluded the basal Zn concentration in wheat-soy diet is inadequate to fulfill the broiler chickens genetic potential in growth and a minimum of 70 mg/kg dietary Zn concentration is suggested to optimize broiler chickens performance.

Determination of the Optimal Level of Dietary Zinc for Newly Weaned Pigs: A Dose-Response Study

Simple Summary

Piglets have a very low feed intake immediately after weaning. We hypothesise that the EU-legislated maximum dietary zinc concentration (150 mg zinc/kg diet) will increase the risk of zinc deficiency after weaning. Zinc deficiency includes symptoms such as impaired growth and increased risk of diarrhoea. However, a high dietary zinc concentration has an antimicrobial effect on the bacteria and increases the risk of antimicrobial resistance. The findings of this study show that the dietary zinc level had a quadratic effect on growth, with a turning point at an approximately 1400 mg zinc per kg diet. The risk of diarrhoea increased up to 60% for pigs that had a blood zinc concentration which decreased after weaning. Maintaining the blood zinc concentration seven days after weaning required up to 1121 mg zinc per kg diet. There was no evidence for an antimicrobial effect when feeding pigs a diet with up to 1601 mg zinc per kg.

Abstract

One hundred and eighty individually housed piglets with an initial body weight of 7.63 ± 0.98 kg (at 28 days of age) were fed a diet containing either 153, 493, 1022, 1601, 2052 or 2407 mg zinc/kg (added Zn as zinc oxide; ZnO) from day 0–21 post weaning to determine the optimal level of Zn for weaned piglets. Body weight, feed intake and faecal scores were recorded, and blood and faecal samples were collected. Dietary Zn content quadratically affected both feed intake and gain in the first two weeks, with an approximately 1400 mg Zn/kg diet and a Zn intake of 400 mg/day as the optimal levels. The relative risk of diarrhoea increased up to 60% at day 7 and 14 if serum Zn status dropped below the weaning level (767 µg/L), and maintain the weaning serum Zn status required approximately 1100 mg Zn/kg (166 mg Zn/day) during week 1. Blood markers of intestinal integrity (D-lactate and diamine oxidase) were unaffected by dietary Zn, and dietary Zn levels of 1022 and 1601 mg/kg did not affect the faecal numbers of total bacteria, Lactobacilli and E. Coli bacteria compared to 153 mg Zn/kg. These results indicate that the requirement for Zn in newly weaned piglets may be substantially higher than currently assumed.

Dietary Pharmacological Zinc and Copper Enhances Voluntary Feed Intake of Nursery Pigs

The objective of the three experiments herein were to characterize the effect of pharmacological zinc and copper concentrations on nursery pig feed intake, stomach ghrelin, energy and nutrient digestibility, and mineral retention in post-weaned pigs. In Expt. 1, 300 weaned pigs were allotted across three dietary treatments (n = 10 pens/treatment) and fed in two diet phases (P1 and P2) lasting 7 and 14 days, respectively. Treatments were: (1) Control diet with no pharmacological minerals in P1 and P2, CON; (2) CON + 3,000 mg/kg Zn and 200 mg/kg Cu (P1), no pharmacological minerals in P2, ZC-CON; and (3) CON + 3,000 mg/kg Zn and 200 mg/kg Cu (P1), CON + 2,000 mg/kg Zn and 200 mg/kg Cu (P2); ZC. Over the 21-day test period, ZC pigs had 15% higher ADG and 13–24% ADFI compared to the CON and ZC-CON pigs (P &lt; 0.05). ZC-CON and ZC pig daily feed intakes were 29 and 73% higher by day 5 and 7 post-weaning, respectively, compared to the CON pigs (P &lt; 0.0001). However, removing pharmacological minerals in P2 abruptly decreased ZC-CON daily feed intake within 24 h to similar intakes as the CON compared to the ZC pigs (0.17, 0.14, and 0.22 kg/d, respectively, P &lt; 0.05). Dietary pharmacological minerals increased stomach fundus ghrelin-positive cells than CON pigs at day 7 (P = 0.005) and day 21 (P &lt; 0.001). However, fasting plasma total and acyl-ghrelin concentrations did not differ from a control in response to zinc oxide daily drenching (Expt. 2). Expt. 3 showed that zinc and copper to have moderate to low retention; however, pharmacological zinc and copper diets increased zinc (P &lt; 0.05) and copper retention (P = 0.06) after 28 days post-weaning compared to control pigs. Pharmacological zinc and copper did not improve digestible energy, metabolizable energy or nitrogen balance. Altogether, dietary pharmacological zinc and copper concentrations improve growth rates and mineral retention in nursery pigs. This improved performance may partially be explained by increased stomach ghrelin abundance and enhanced early feed intake in newly weaned pigs fed pharmacological concentrations of zinc and copper.

Zinc supplementation modifies brain tissue transcriptome of Apis mellifera honeybees

BACKGROUND

Bees are the most important group of pollinators worldwide and their populations are declining. In natural conditions, Apis mellifera depends exclusively on food from the field to meet its physiological demands. In the period of scarcity, available resources are insufficient and artificial supplementation becomes essential for maintaining the levels of vitamins, proteins, carbohydrates, and minerals of colonies. Among these minerals, zinc is essential in all living systems, particularly for the regulation of cell division and protein synthesis, and is a component of more than 200 metalloenzymes.

RESULTS

The total RNA extracted from the brain tissue of nurse bees exposed to different sources and concentrations of zinc was sequenced. A total of 1,172 genes in the treatment that received an inorganic source of zinc and 502 genes that received an organic source of zinc were found to be differentially expressed among the control group. Gene ontology enrichment showed that zinc can modulate important biological processes such as nutrient metabolism and the molting process.

CONCLUSIONS

Our results indicate that zinc supplementation modulates the expression of many differentially expressed genes and plays an important role in the development of Apis mellifera bees. All the information obtained in this study can contribute to future research in the field of bee nutrigenomics.

Evaluating the Influence of Different Recommended Dietary Levels of Cu and Zn on Finishing Pigs

This study was conducted to evaluate the effects of dietary supplementation of different recommended levels of Cu and Zn on antioxidant capacity, tissue mineral status, minerals excretion, meat quality, digestive enzyme activity, and metal transporters in finishing pigs. A total of 120 pigs (with an average initial body weight (BW) of 70.0 ± 2.1 kg) were randomly divided into four treatments: (1) basal diet without added Cu or Zn (control), (2) basal diet+35 mg cupreous N-carbamylglutamate chelate (NCG-Cu) +150 mg zinc-methionine chelate (Zn-Met) (AC), (3) basal diet + 3.0 mg of NCG-Cu + 43 mg Zn-Met (CN), and (4) basal diet + 3.5 mg NCG-Cu + 50 mg Zn-Met (NRC100). Pig growth performance was not affected by the level of Cu or Zn. Among the four treatments, the AC treatment had the highest concentration (P < 0.05) of glutathione peroxidase (GSH-Px). Pigs fed the AC diet had the highest (P < 0.05) liver Zn, fecal Cu, and fecal Zn among the four treatments. The protein levels of trypsin and aminopeptidase N (APN) in the intestinal mucosa showed their highest levels (P < 0.05) in the NRC100 and AC treatments. The mRNA levels of trypsinogen and APN were significantly up-regulated (P < 0.05) in the AC, CN, and NRC100 treatments compared with the control. The mRNA levels for the Zn transporter genes SLC30A1 (ZnT1) and SLC30A2 (ZnT2) were significantly up-regulated (P < 0.05) in the AC treatment, and the mRNA levels for SLC39A4 (ZIP4) and metallothionein 1 (MT) in the AC, CN, and NRC100 treatments were significantly up-regulated (P < 0.05) compared with the control. Meat quality were not affected (P > 0.05) by the different recommended levels of Cu and Zn. These results indicated that the supplemental Cu and Zn levels routinely used in AC diets in Chinese commercial feed enterprises should be reduced.

Dietary Copper Supplementation Increases Growth Performance by Increasing Feed Intake, Digestibility, and Antioxidant Activity in Rex Rabbits

Copper is often used as a growth promoter, at the same time copper is one of the most important essential trace elements for fur animals, especially Rex rabbits. However, too much copper added to the diet may harm animal health, and copper excreted in feces can pollute the environment. In this study, 3-month-old Rex rabbits were randomly divided into four groups and fed a basal diet containing 0, 30, 60, or 120 mg/kg Cu for 5 weeks. The diet supplemented with 30 mg/kg Cu significantly increased (P < 0.05) the average daily feed intake (ADFI) and the average daily gain (ADG) and also the activity of serum Cu-Zn (zinc) superoxide dismutase and the digestibility of ether extract. Supplemental Cu up to 120 mg/kg did not significantly adversely affect the Zn metabolism of growing Rex rabbits. Overall, the data in this study indicate that 30 mg/kg is the optimal level of Cu supplementation in the diet of growing Rex rabbits. The results will provide a reference to improve the breeding of Rex rabbits and possibly other animals. In follow-up studies, the amount of copper in the diet should be reduced as much as possible from the baseline of 30 mg/kg copper.

Study the Effect of Microinjection of Zn, Fe, and Cu Loaded in Montmorillonite on Development Activities in Fertilized Chicken Eggs

This study aims to reduce embryonic mortality, increase body weight, and improve immune system in chicken. A total of 240 eggs were assigned to three treatments (n = 60) and injected with cooper (Cu), zinc (Zn), and iron (Fe) loaded by montmorillonite (Mnt), and one untreated group (n = 60). Some hormones and enzymes related with growth were measured in terms of serum, and expression of some genes related to growth, immune, and programmed cell deaths that were determined in the liver and spleen of chicken by RT-qPCR. The embryonic death on the fifth and seventh days after injecting eggs with Fe-Mnt was less obvious than in other groups. The heaviest body weight was recorded for Fe-Mnt and Cu-Mnt treatment. Fe-Mnt treatment had higher serum GSH, SOD, GH, and Myostatin contents and lower MDA than those in the other treatments. Cu-Mnt treatment included the highest contents of CAT enzyme and IGF-1 hormone in serum. The highest expression of IGF-1, GH, BCL6, and SYK genes in liver tissue were recorded by Zn-Mnt, IGFBP2, FGF8, and IFNW1 genes by Cu-Mnt, and TC1RG1 and IFNW1 genes by Fe-Mnt in spleen tissue. In conclusion, Fe-Mnt was the best treatment for reducing embryonic mortality, and increasing body weight of chickens and expression of growth and immune genes, followed by Cu-Mnt treatment.

Single or Combined Applications of Zinc and Multi-strain Probiotic on Intestinal Histomorphology of Broilers Under Cyclic Heat Stress

Two-hundred-eighty-day-old broiler chicks were divided into seven groups. The groups were designated as T1, thermoneutral zone; T2, heat stressed (HS); T3, HS + zinc (Zn) supplementation (30 mg/kg); T4, HS + Zn (60 mg/kg); T5, HS + probiotic (0.1 g/kg); T6, HS + probiotic (0.1 g/kg) + Zn (30 mg/kg); and T7, HS + Zn (60 mg/kg) + probiotic (0.1 g/kg). Significant decrease (p < 0.05) was observed in villus height (VH), VH to crypt depth ratio, and villus surface area of all intestinal segments in the T2 group when compared with the T1 group. The same parameters had significantly higher (p < 0.05) values in the jejunum and ileum of the Zn- and probiotic-supplemented groups (alone + combination) when compared with the T2 group. The birds exposed to HS showed fewer (p < 0.05) intraepithelial lymphocytes (IELs) in the jejunum and ileum than the T1 group, while their count increased in the jejunum and ileum with dietary treatments. In conclusion, Zn and probiotic positively modulated the intestinal microstructures of broilers kept under high environmental temperature.

Dietary copper/zinc-loaded montmorillonite improved growth performance and intestinal barrier and changed gut microbiota in weaned piglets

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, intestinal barrier and gut microbiota of weaned pigs were investigated in the present study. A total of 108 piglets (Duroc × Landrace × Yorkshire; 6.36 kg; weaned at 21 ± 1 d age) were used in this experiment. The pigs were randomly assigned to three treatments with six replicates, six pigs in each replicate. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet supplemented with 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; and (3) Cu +Zn +Mt group: basal diet supplemented with the mixture of copper sulphate, zinc sulphate and montmorillonite (equivalent to the copper and zinc in the Cu/Zn-Mt treatment). The results indicated that, compared with the pigs from control group, average daily gain and gain: feed ratio were increased and the faecal score on days 7 and 14 after weaning was decreased by supplementation of Cu/Zn-Mt; intestinal transepithelial electrical resistance (TER) and expressions of tight junction protein claudin-1 and zonula occludens-1 were increased, and intestinal permeability of fluorescein isothiocyanate-dextran 4 kDa was decreased by supplementation with Cu/Zn-Mt. According to the Illumina-based sequencing results, Cu/Zn-Mt supplementation increased the relative abundance of core bacteria (Lactococcus, Bacillus) at genus level and decreased the potentially pathogenic bacteria (Streptococcus and Pseudomonas) in colon of weaned piglets. However, the piglets fed with the mixture of copper sulphate, zinc sulphate and montmorillonite showed no effects in above parameters in comparison with the pigs from control group. In conclusion, dietary Cu/Zn-Mt could improve growth performance, decrease the diarrhoea and improve intestinal barrier and bacterial communities of weaned pigs. The results indicated that 'loading' of montmorillonite with Zn and Cu changed not only its chemical but also its nutritional properties.

Towards Zero Zinc Oxide: Feeding Strategies to Manage Post-Weaning Diarrhea in Piglets

Simple Summary

Zinc oxide (ZnO) supplementation at pharmacological doses in post-weaning piglets is a consolidated practice that allows efficient control of post-weaning diarrhea (PWD), a condition exacerbated by Escherichia coli F4 (K88) infections. Far from being completely elucidated, the multifactorial ZnO mechanism of action is in all likelihood exerted at the gastrointestinal level. However, increasing environmental concerns are arising from prolonged ZnO use. This article reviews the utilization of ZnO in piglets, the biological rationale behind its powerful activity, and the emerging threats that are leading towards a significant reduction in its use. Finally, a wide analysis of the strengths and weaknesses of innovative alternative strategies to manage PWD at the nutritional level is given.

Abstract

Zinc oxide (ZnO) at pharmacological doses is extensively employed in the pig industry as an effective tool to manage post-weaning diarrhea (PWD), a condition that causes huge economic losses because of its impact on the most pivotal phase of a piglet’s production cycle. In a multifactorial way, ZnO exerts a variety of positive effects along the entire gastrointestinal tract by targeting intestinal architecture, digestive secretions, antioxidant systems, and immune cells. ZnO also has a moderate antibacterial effect against Escherichia coli F4 (K88), the main causative agent of PWD. However, the environmental impact of ZnO and new emerging threats are posing serious questions to the sustainability of its extensive utilization. To work towards a future free from pharmacological ZnO, novel nutritional approaches are necessary, and many strategies have been investigated. This review article provides a comprehensive framework for ZnO utilization and its broad mode of action. Moreover, all the risks related to pharmacological ZnO levels are presented; we focus on European institutions’ decisions subsequently. The identification of a novel, complete solution against PWD should be accompanied by the adoption of holistic strategies, thereby combining good management practices to feeding approaches capable of mitigating Escherichia coli F4 (K88) infections and/or lowering ZnO utilization. Promising results can be obtained by adjusting diet composition or employing organic acids, natural identical compounds, polyphenol-rich extracts, prebiotics, and probiotics.

A reduced CP level without medicinal zinc oxide does not alter the intestinal morphology in weaned pigs 24 days post-weaning

The use of medicinal zinc oxide (ZnO) to prevent diarrhoea post-weaning will be banned in the EU from 2022. Therefore, new alternatives are needed to avoid an increase in diarrhoea and higher antibiotic use. A low dietary CP level has shown to lower the frequency of diarrhoea in pigs, due to lower microbial protein fermentation in the colon as well as improved conditions in the small intestine after weaning. The objective of this study was to examine the effect of decreased CP levels post-weaning as an alternative to medicinal ZnO on gut morphology and histopathology. Five hundred and sixty pigs were randomly assigned into one of six groups receiving a two-phase diet from 5.5 to 15 kg: positive control group (PC) with medicinal ZnO and standard levels of protein (19.1-18.4% CP), negative control group (NC) without medicinal ZnO and standard levels of protein (19.1-18.4% CP). The remaining four low protein groups were a low-standard (LS) CP level (16.6-18.4% CP), a low-low (LL) CP level (16.6-16.2% CP), a very low-high (VLH) CP level (14-19.3% CP) and a very low-medium (VLM) CP level (14-17.4% CP). Individual BW was recorded at day 0, 10 and 24 post-weaning, and all antibiotic treatments were recorded. Tissue samples from the small intestine (mid-jejunum) for morphological and histopathologic analysis, organ weights, blood and urine samples were collected at day 10 and 24 post-weaning from a total of 90 sacrificed weaners. The results demonstrated no differences in intestinal morphology between groups, but the histopathology showed a damaged brush border score in VLM and VLH pigs . In addition, a lower blood urea nitrogen in VLM pigs at 24 days was found. The LL and VLM pigs had a significantly decreased average daily gain in the overall trial period compared to PC and NC pigs. Conclusively, intestinal brush border was damaged by the very low protein diet at 24 days post-weaning, but intestinal morphology was unaffected by dietary strategy.

Puerarin Rebuilding the Mucus Layer and Regulating Mucin-Utilizing Bacteria to Relieve Ulcerative Colitis

The colonic mucus barrier serves as a primary defense against enteric pathogens; destruction of this mucus layer has been observed in ulcerative colitis patients. This study aims to investigate the possibility of rebuilding the colon mucus layer through puerarin supplementation, which can stimulate mucin secretion and goblet cells differentiation. After puerarin supplementation, the thickness of colon mucus layer was increased and the permeability was reduced. The erosion of intestinal epithelium by bacteria was blocked, and the loss of epithelial integrity was alleviated. Puerarin also altered the composition of mucin-utilizing bacteria, which influenced the mucus permeability. Levels of short-chain fatty acids (SCFAs) were increased after puerarin supplementation, which as a direct source of energy for the proliferation of epithelia and goblet cells. This study demonstrated that enhancement of mucin secretion to relieve ulcerative colitis (UC) by puerarin supplementation is feasible, and the regulation of mucin-utilizing bacteria and the increased levels of SCFAs may be the main reasons.

Evaluating effects of zinc hydroxychloride on biomarkers of inflammation and intestinal integrity during feed restriction

Objectives were to evaluate effects of supplemental zinc hydroxychloride (HYD; Micronutrients, Indianapolis, IN) on gut permeability, metabolism, and inflammation during feed restriction (FR). Holstein cows (n = 24; 159 ± 8 d in milk; parity 3 ± 0.2) were enrolled in a 2 × 2 factorial design and randomly assigned to 1 of 4 treatments: (1) ad libitum fed (AL) and control diet (ALCON; 75 mg/kg Zn from zinc sulfate; n = 6); (2) ad libitum fed and HYD diet (ALHYD; 75 mg/kg Zn from HYD; n = 6); (3) 40% of ad libitum feed intake and control diet (FRCON; n = 6); or (4) 40% of ad libitum feed intake and HYD diet (FRHYD; n = 6). Prior to study initiation, cows were fed their respective diets for 21 d. The trial consisted of 2 experimental periods (P) during which cows continued to receive their respective dietary treatments. Period 1 (5 d) served as the baseline for P2 (5 d), during which cows were fed ad libitum or restricted to 40% of P1 feed intake. In vivo total-tract permeability was evaluated on d 4 of P1 and on d 2 and 5 of P2, using the paracellular permeability marker chromium (Cr)-EDTA. All cows were euthanized at the end of P2 to assess intestinal architecture. As anticipated, FR cows lost body weight (∼46 kg), entered into calculated negative energy balance (-13.86 Mcal/d), and had decreased milk yield. Circulating glucose, insulin, and glucagon decreased, and nonesterified fatty acids and β-hydroxybutyrate increased in FR relative to AL cows. Relative to AL cows, FR increased lipopolysaccharide-binding protein, serum amyloid A (SAA), and haptoglobin (Hp) concentrations (2-, 4-, and 17-fold, respectively); and peak SAA and Hp concentrations were observed on d 5. Circulating SAA and Hp from FRHYD tended to be decreased (47 and 61%, respectively) on d 5 relative to FRCON. Plasma Cr area under the curve increased (32%) in FR treatments on d 2 and tended to be increased (17%) on d 5 of P2 relative to AL treatments. No effects of diet were observed on Cr appearance. Relative to AL cows, FR increased jejunum villus width and decreased jejunum crypt depth and ileum villus height and crypt depth. Relative to FRCON, ileum villus height tended to increase in FRHYD cows. Feed restriction tended to decrease jejunum and ileum mucosal surface area, but the decrease in the ileum was ameliorated by dietary HYD. In summary, FR induced gut hyperpermeability to Cr-EDTA, and feeding HYD appeared to benefit some key metrics of barrier integrity.

Analysis of Gastrointestinal Responses Revealed Both Shared and Specific Targets of Zinc Oxide and Carbadox in Weaned Pigs

Antibiotics and pharmacological zinc supplementation were commonly used as growth promoters for several decades in the swine industry before being limited because of public health and environmental concerns. Further, the physiological and metabolic responses associated with their growth promotion effects are unclear. To characterize these responses induced by pharmacological zinc supplementation (2500 mg/kg) and carbadox (55 mg/kg), 192 post-weaning pigs were fed basal and test diets for 43 days. Compared with basal, pharmacological zinc and carbadox independently improved growth performance. Pharmacological zinc increased gastric mucosa thickness compared with basal zinc, while carbadox increased intestinal villus:crypt ratio compared with non-carbadox. Pharmacological zinc and carbadox independently reduced interleukin (IL)-1β concentration compared with basal zinc and non-carbadox. Pharmacological zinc increased IL-1RA:IL-1 ratio by 42% compared with basal zinc, while carbadox tended to increase the IL-10 and IL10:IL-12 ratio compared with non-carbadox. Carbadox increased fecal concentrations of histidine and lysine compared with non-carbadox. The independent effect of pharmacological zinc and carbadox on morphology and nutrient metabolism, and their shared effect on immunity may contribute to the additive effect on growth promotion. These results further confirmed the concept that growth promotion is multifactorial intervention. Therefore, elucidating growth-promoting effects and searching for alternatives should include wide-spectrum evaluation.

The effect of lactose and a prototype Lactobacillus acidophilus fermentation product on digestibility, nitrogen balance, and intestinal function of weaned pigs

The objective of this study was to determine the effects of lactose (LA) and a prototype Lactobacillus acidophilus fermentation product (FP) on growth performance, diet digestibility, nitrogen (N) balance, and intestinal function of weaned pigs. Twenty-eight newly weaned pigs [approximately 21 d of age; initial body weight (BW) = 5.20 ± 0.15 kg] were housed in metabolism crates and assigned to one of four treatments (n = seven pigs per treatment) corresponding to a 2 × 2 factorial design: with (LA+; 15% inclusion) or without (LA-) LA and with (FP+) or without (FP-) the prototype FP (1 g of FP per kilogram of diet; Diamond V, Cedar Rapids, IA). Feed and water were provided ad libitum. At day 5, pigs were orally given lactulose and mannitol to assess small intestinal permeability. Fecal samples were collected on days 5-9 to determine the apparent total tract digestibility (ATTD) of dry matter (DM), gross energy (GE), and N. Total urine output and fecal samples were collected on days 10-13 to determine N retention. On day 15, all pigs were euthanized to collect intestinal lumen and tissue samples. Data were analyzed for the main effects of LA and FP and their interaction using the MIXED procedure of SAS. Lactose improved average daily feed intake (ADFI; P = 0.017), the ATTD of DM (P = 0.014), the ATTD of GE (P = 0.028), and N retention (P = 0.043) and tended to increase the butyric acid concentration in the colon (P = 0.062). The FP tended to increase the digestibility of N (P = 0.090). Neither LA nor the FP affected intestinal barrier function or inflammation markers. The interaction between LA and FP affected intestinal morphology: in the jejunum, pigs fed LA+FP- had increased villus height compared with those fed LA+FP+ and LA-FP-, whereas LA+FP+ was intermediate (interaction P = 0.034). At the terminal ileum, pigs fed LA-FP+ and LA+FP- had increased villus height and villus: crypt compared with those fed LA-FP-, whereas LA+FP+ was intermediate (interaction P = 0.007 and P = 0.007, respectively). In conclusion, the addition of LA brings important nutritional attributes to nursery diets by improving feed intake, digestibility of DM and GE, and the N retention of weaned pigs; however, the functional capacity of LA to improve markers of intestinal function is limited. On the other hand, the FP showed only a mild increase in the digestibility of N but a limited capacity to improve markers of intestinal function.

Interactive effects of zinc and copper sources and phytase on growth performance, mineral digestibility, bone mineral concentrations, oxidative status, and gut morphology in nursery pigs

This study investigated the interactive effects of zinc (Zn) and copper (Cu) sources and phytase on growth performance, oxidative status, mineral digestibility, tissue mineral concentrations, and gut morphology in nursery pigs. A total of 288 weaning barrows [body weight (BW) = 5.71 ± 0.81 kg], blocked by initial BW, were randomly allotted to one of eight dietary treatments, with nine pens per treatment and four pigs per pen. The eight dietary treatments were arranged in 2 × 2 × 2 factorial design, with two Zn sources [2,000, 2,000, and 100 mg/kg Zn from zinc oxide (ZnO) during phase 1 (days 1–14) and phase 2 (days 15–28), and phase 3 (days 29–42), respectively; 100 mg/kg Zn from zinc methionine hydroxy analogue chelate (Zn-MHAC) from phases 1 to 3], two Cu sources [150, 80, and 80 mg/kg Cu from copper sulfate (CuSO₄) or copper methionine hydroxy analogue chelate (Cu-MHAC) during phases 1–3, respectively], and two phytase inclusion levels (0 or 500 FTU/kg). Results showed that ZnO supplementation at 2,000 mg/kg Zn significantly increased average daily feed intake (ADFI; P = 0.01) and average daily gain (ADG; P = 0.03) during phase 1 compared to Zn-MHAC group; however, Zn-MHAC supplementation tended (P = 0.06) to improve gain to feed ratio (G:F) during phase 2 compared to ZnO group. There were no differences (P > 0.10) between ZnO and Zn-MHAC groups in terms of ADG, ADFI, and G:F during the entire nursery period. Compared with CuSO₄, Cu-MHAC tended to increase ADG (P = 0.07) and G:F (P = 0.08) during the entire nursery period. Phytase supplementation significantly increased ADG (P < 0.01), ADFI (P < 0.01), and G:F (P < 0.01) during the entire nursery period compared with no phytase supplementation. There was a significant interaction (P < 0.01) between Zn source and phytase on standardized total tract digestibility (STTD) of phosphorus (P), whereas there was no interaction (P = 0.21) between Cu sources and phytase on STTD of P. However, there was a significant interaction between Cu sources and phytase on calcium (Ca; P = 0.02) and P (P = 0.03) concentrations in metacarpal bones and G:F in phase 2 (P = 0.09). Furthermore, pigs fed diets containing Zn-MHAC tended to have lower ileum villus width (P = 0.07), compared with those fed diets containing ZnO, and pigs fed diets containing Cu-MHAC tended to have lower plasma malondialdehyde concentration (P = 0.10) compared with those fed diets containing CuSO₄. In conclusion, under the conditions of the current study, ZnO supplementation at 2,000 mg/kg Zn was only effective in the first 2 wk postweaning, whereas Zn-MHAC supplementation at 100 mg/kg Zn could achieve better feed efficiency during phase 2 compared to pharmacological levels of ZnO, therefore, leading to no difference of growth performance in the entire nursery period. Low levels of Zn-MHAC may improve phytase efficacy on degrading phytate P compared to pharmacological levels of ZnO. Cu-MHAC may be more effective to promote growth compared to CuSO₄, which may be partially driven by reduced oxidative stress. Results also indicated that Cu-MHAC might exert a synergistic effect with phytase on improving feed efficiency and bone mineralization.

Antioxidant and Anti-Inflammatory Effects of Different Zinc Sources on Diquat-Induced Oxidant Stress in a Piglet Model

Zinc (Zn) plays a crucial role in reducing oxidative stress and diarrhea in postweanling piglets. This study is aimed at comparing the effects of zinc chelate of 2-hydroxy-4 methyl-thio butanoic acid (HMZn) and ZnSO₄ on the oxidative stress in weaned piglets. A total of 32 piglets were randomly divided into 4 treatments: CON: basal diet+80 mg/kg Zn as ZnSO₄; DIQ: basal diet+80 mg/kg Zn as ZnSO₄; HMZn: basal diet+200 mg/kg Zn as HMZn; and ZnSO₄: basal diet+200 mg/kg Zn as ZnSO₄. On day 15, the DIQ, HMZn, and ZnSO₄ groups were injected intraperitoneally with diquat except for the CON group. The trial lasted 21 days. The results showed that zinc sources did not influence the growth performance during the first 14 days. But HMZn increased activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and total antioxidant capacity (T-AOC) in serum (P < 0.05). After diquat injection, the fecal score was decreased in the HMZn group. Both HMZn and ZnSO₄ increased the activities of GPX and T-AOC in serum and the relative mRNA expressions of hepatic and renal Nrf2, SOD1, and GPX compared with the DIQ group (P < 0.05). Moreover, the relative mRNA expression of inflammatory factors in the small intestine, liver, and kidney was downregulated; the phosphorylation of NF-κB protein was inhibited in the HMZn group compared with the DIQ and ZnSO₄ groups (P < 0.05). In general, HMZn showed notable advantage over ZnSO₄ in reducing diarrhea and improving antioxidant and anti-inflammatory ability in piglets challenged with diquat.

Performance, rumen fermentation, blood minerals, leukocyte and antioxidant capacity of young Holstein calves receiving high-surface ZnO instead of common ZnO

This study was conducted to assess the effect of feeding high-surface ZnO instead of common ZnO on the performance, rumen fermentation, blood minerals, leukocytes and antioxidant capacity of pre- and post-weaning calves. Thirty male suckling Holstein calves were allotted to one of three experimental groups (10 replicates) in a completely randomised design. Calves received: (1) a low Zn diet without Zn supplementation (control diet), (2) a high Zn diet containing 50 mg supplementary Zn/kg dry matter (DM) as common ZnO or (3) a high Zn diet containing 50 mg supplementary Zn/kg DM as high-surface ZnO (nano-ZnO). The control diet contained a native Zn content of 35.5, 34.7 or 33.7 mg/kg DM for the age periods of 7 to 30, 31 to 70 and 71 to 100 d, respectively. Supplementation of the diet with Zn did not change the dry matter intake (DMI) of calves during d 7 to 30 but increased the ADG in this period (p < 0.05). During age periods of 31 to 70 and 71 to 100 d, DMI and ADG of the Zn supplemented calves were higher (p < 0.05) than the control animals. The nutrient digestibility and the concentration of rumen volatile fatty acids were positively affected (p < 0.05) and the rumen ammonia-N concentration decreased (p < 0.05) by dietary Zn supplementation. Furthermore, the incidence of diarrhoea and pneumonia was lower in calves receiving the Zn supplemented diets. Irrespective of ZnO source, the blood total antioxidant capacity, leukocyte and haematocrit levels significantly increased (p < 0.05) with the ZnO supplemented diets. The post-weaning DMI, nutrient  digestibility and blood haematocrit levels were higher in calves receiving high-surface ZnO, compared to those supplemented with common ZnO. With inclusion of the Zn sources in pre- and post-weaning diets, the blood Zn concentration increased (p < 0.05), but the blood Cu, Fe, Ca, P and Mg levels remained unchanged. Regardless of source, dietary supplementation of young calves with ZnO improved the performance and decreased rumen ammonia-N and the incidence of diseases. Moreover, high-surface ZnO had advantages over common ZnO in increasing the post-weaning feed intake, digestibility and blood Zn concentration.

Zinc and Copper with New Triazine Hydrazone Ligand: Two Novel Organic Complexes Enhanced Expression of Peptide Growth Factors and Cytokine Genes in Weaned V-Line Rabbit

Simple Summary

Zinc and Copper are two important trace minerals, which are involved in numerous vital biological activities in animal’s body, such as enzyme activation and enhancement of immune function, growth, reproduction, DNA synthesis, cell division, and neurotransmitters production. Recently, the application of trace mineral organic complexes in animal feed received much more attention than the inorganic sources. The organic sources can contribute significantly to improving animals’ health and reproduction, as the minerals are more biologically available and absorbable than they are when coming from the inorganic sources. In this study, three injectable varieties of Zn and Cu supplementation, sulfate, inorganic (loaded with montmorillonite), and novel organic (ligand with triazine hydrazone), were tested with weaned rabbits. The results revealed that these three mineral types vary at the most biological responses, and only one category of our novel organic complexes provided consistent animal performance improvement, including weight gain, serum antioxidant, meat quality, intestine morphometry, and the expression of peptide growth factors and cytokine genes. To our knowledge, this is the first work on the Zn and Cu with triazine hydrazone ligand as two organic complexes in rabbits.

Abstract

Two novel transitional organic Zn/Cu complexes based on a new biocompatible bidentate triazine–hydrazone ligand (Thz) was designed, synthesized, and evaluated in this study. This study evaluated the effects of injecting 60 mg of Zn and 40 mg of Cu in three different forms, twice per week, for eight weeks on growth performance, expression of growth factors and cytokine genes, carcass yield, blood biochemicals, and intestinal morphology in weaned rabbits. The tested complexes were sulfate (Cu/ZnSO₄), montmorillonite (Cu/Zn-Mnt), and triazine hydrazone (Cu/Zn-Thz). A total of 60 V-line weaned rabbits at four weeks of age were assigned to four treatments (n = 15), which were intramuscularly injected with 0.5 mL of either (1) saline (control) or saline containing (2) Cu/ZnSO₄, (3) Cu/Zn-Mnt, or (4) Cu/Zn-Thz. Compared to the controls, the rabbits injected with Cu/Zn-Thz showed a higher (p < 0.01) growth rate, carcass yield (p < 0.05), and liver expression of insulin like growth factor-1 (IGF-1), growth hormone receptor (GHR), fibroblast growth factor-1 (FGF1), and transforming growth factor beta-1 (TGFB1) (p < 0.05), as well as better jejunum morphometric variables (p < 0.05). On the other hand, mRNA of FGF1, TGF1, TCIRG1, and adenosine deaminase (ADA) were higher expressed (p < 0.05) in the spleen tissues of Cu/Zn-Mnt group. Collectively, the results indicated that our novel synthesized organic complexes of Zn/Cu-Thz proved to be a suitable feed supplement, as it increased rabbit productive performance through enhancing expression of peptide growth factors and cytokine genes.

The effects of dietary supplementation with porous zinc oxide on growth performance, intestinal microbiota, morphology, and permeability in weaned piglets

The objective of this experiment was to evaluate the effects of dietary supplementation with porous zinc oxide (HiZox) on growth performance, intestinal microbiota, morphology, and permeability in weaned piglets. A total of 128 weaned piglets [(Landrace × Yorkshire) × Duroc] with an average body weight (BW) of (6.55 ± 0.25 kg; 21 d of age) were randomly assigned to four dietary treatments: (1) a corn-soybean basal diet; (2) basal diet + 3,000 mg/kg conventional ZnO; (3) basal diet + 200 mg/kg HiZox; (4) basal diet + 500 mg/kg HiZox. The experiments lasted for 28 days. Incremental HiZox in the diet increased ADG (linear p = 0.015; quadratic p = 0.043) and ADFI (linear p = 0.027; quadratic p = 0.038), and the diarrhea index decreased linearly and quadratically (p < 0.01) as HiZox supplemented increased. Furthermore, supplementation with HiZox increased the amounts of Lactobacillus spp. (p < 0.05) in the ileum and cecum in comparison with that of control treatment or 3,000 mg/kg ZnO treatment, while decreased the populations of Escherichia coli, Clostridium coccoides, and Clostridium. leptum subgroup (p < 0.05) in the ileum and cecum relative to those in control treatment. The addition of HiZox increased the villus height and villus-to-crypt ratio (VC) of duodenum, jejunum, and ileum (p < 0.05), while decreased the crypt depth of jejunum (p < 0.05) and tended to reduce the crypt depth of duodenum (p < 0.10) compared with the control treatment. Piglets fed with 500 mg/kg HiZox had lower serum D-lactate and diamine oxidase (DAO) than those fed with basal control diet or 3,000 mg/kg ZnO diet (p < 0.01). The results suggested that supplementation with HiZox modulated intestinal microbial composition and improved intestinal morphology, which may exert protective effects on the integrity of the mucosal barrier function of weaned piglets, was as efficacious as pharmaceutical doses of ZnO in enhancing growth performance, indicating that the HiZox may be a promising alternative to pharmaceutical doses of ZnO.

Mucosubstances in the porcine gastrointestinal tract: Fixation, staining and quantification

Mucins are of great interest in intestinal research and histochemical methods are often employed to identify them. Since it is in the nature of mucins that they are "hard to hold onto" once they come into contact with water, a frequently used medium in histochemistry, there are a number of challenges that may decrease diagnostic accuracy. As the outcome of methods published for microscopic detection of mucosubstances proved to be unsatisfactory in our hands, the aim was the establishment of a reliable and reproducible protocol. Tissue samples were available from pig feeding experiments. In the present study, we focus on a fixation / staining procedure without making comparisons between differently fed pigs. Several fixation and staining procedures were evaluated for their use in semiautomatic quantification and quality assessment of different mucus fractions simultaneous on one tissue section. Cryostat sectioning, subsequent fixation steps with heat, ethanol and modified Bouin's solution, followed by triple staining with high iron diamine, alcian blue and periodic acid-Schiff turned out to be the best method to identify sulfomucin, sialomucin and neutral mucin simultaneous on one tissue section. This methodology resulted in very good morphology of goblet cells with intact mucin containing vesicles within the cells, which was comparable to ultrastructural electron microscopical observations. Semiautomatic quantification of different mucins was possible. In conclusion, reliable mucus quantification and assessment of mucus quality requires strictly tested procedures. According to our experience, the most important aim after cryosectioning is fast fixation of the mucosubstances, which requires a combination of different fixation steps.

Zinc overload in weaned pigs: tissue accumulation, pathology, and growth impacts

Zinc oxide (ZnO) is commonly fed to pigs at pharmacologic concentrations (2,000-3,000 ppm) for the first 3 wk post-weaning to increase growth and reduce enteric bacterial disease. The safety of this high-dose treatment is assumed based upon lower bioavailability of ZnO compared to other common forms of Zn in feed; however, limited data are available regarding the specific serum and tissue concentrations of Zn expected in animals experiencing overload following feeding of excessive ZnO. Fifty-five 3-wk-old pigs were divided into 5 groups receiving various concentrations of ZnO (0-6,000 ppm) for 3 wk. Pigs receiving 6,000 ppm ZnO had higher mean pancreatic Zn concentrations (p < 0.001) compared to other treatments, and higher pancreatic Zn concentrations were associated with pancreatic acinar cell apoptosis (p < 0.0001). Hepatic Zn concentrations were highest for pigs receiving 6,000 ppm ZnO (mean ± SEM; 729 ± 264 ppm) and significantly higher than all other groups (p < 0.0001), with controls having concentrations <60 ppm. Similarly, serum Zn was highest in pigs receiving 6,000 ppm ZnO (4.81 ± 2.31 ppm) and significantly higher than all groups (controls, <1 ppm). Additionally, as pigs became overloaded with Zn, there were significant reductions in serum Cu and both serum and hepatic Se. Hepatic and serum Zn concentrations >500 ppm and >2 ppm, respectively, are indicative of Zn overload, and dietary trace mineral analysis is warranted if expected inclusion rates are ≤3,000 ppm ZnO.

Reduced dietary nitrogen with a high Lys:CP ratio restricted dietary N excretion without negatively affecting weaned piglets

We hypothesized that balancing the content of exogenous amino acids, especially lysine, to reduce protein content in swine diets could reduce nitrogen (N) pollution associated with animal husbandry. Two experiments (45 d each experiment) were performed on weaned piglets (Duroc × Landrace × Yorkshire, 28 d of age) to test this and to determine the optimal lysine to crude protein (Lys:CP) ratio in diet. In Exp. 1, 12 piglets (6 replicates [n = 6]) were fed diets containing different levels of CP (17% and 20%) but the same level of Lys. Increased CP content resulted in significant increases (P < 0.05) of average daily gain (ADG), average daily feed intake (ADFI), and body weight (BW), but did not affect the feed to gain ratio. In Exp. 2, 24 piglets (8 replicates [n = 8]) were fed 1 of 3 diets as follows: 1) 20% CP with a regular Lys:CP ratio (6.23%, control); 2) 17% CP with a reduced Lys:CP ratio (6.14%, LL); or 3) 17% CP with a standard Lys:CP ratio (7.32%, SL). The ADG, final BW, serum concentrations of growth hormone and insulin-like growth factor-1, villus height in the jejunum, and villus height to crypt depth ratio were the lowest in piglets fed LL diet, whereas blood urea N concentration was the lowest and the value of lipase activity was the highest in the piglets fed SL diet. The SL diet did not affect growth performance, intestinal morphology, or serum hormone concentrations, indicating that reduced dietary N with a high Lys:CP ratio can efficiently reduce dietary N excretion without negatively affecting weaned piglets.

Menkes disease: Oral administration of glyoxal-bis(N(4)-methylthiosemicarbazonato)-copper(II) rescues the macular mouse

BACKGROUND

Menkes disease is a copper metabolism disorder caused by mutations in ATP7A, a copper-transporting P-type ATPase. In this study, oral copper supplementation via glyoxal-bis(N(4)-methylthiosemicarbazonato)-copper(II) (CuGTSM), a lipophilic copper complex, was investigated in male hemizygous macular (Mo^Ml/y) mice, a mouse model of Menkes disease.

METHODS

CuGTSM was administered by oral gavage on postnatal days 5, 8, 11, 17, 23, and 32. The copper levels in the organs and serum, copper-dependent enzyme activities in the brain, and ceruloplasmin (Cp) activity in the serum were measured at 15 days and 3 and 8 months of age. Histological analysis of the intestines and the rotarod test were also performed.

RESULTS

CuGTSM treatment extended the lifespan of Mo^Ml/y mice and partly restored the copper concentrations and cytochrome oxidase and DBH activities in the brain; however, the rotarod test showed impaired motor performance. The treatment also increased copper concentrations and Cp activity in the serum. In suckling Mo^Ml/y mice, CuGTSM treatment transiently induced diarrhea accompanied by copper accumulation and altered villus morphology in the ileum.

CONCLUSION

Oral administration of CuGTSM extended the lifespan of Mo^Ml/y mice. Oral administration is attractive, but pharmaceutical studies are needed to reduce the adverse enteral effects.

Influences of Copper/Zinc-Loaded Montmorillonite on Growth Performance, Mineral Retention, Intestinal Morphology, Mucosa Antioxidant Capacity, and Cytokine Contents in Weaned Piglets

The effects of copper/zinc-loaded montmorillonite (Cu/Zn-Mt) on growth performance, mineral retention, intestinal morphology, mucosa antioxidant capacity, and cytokine contents in weaned piglets were investigated in the present study. One hundred eight piglets weaned at 21 ± 1 days of age (Duroc × Landrace× Yorkshire; average initial weight of 6.36 kg) were allotted to three treatments for 2 weeks. The three treatments were as follows: (1) control group: basal diet; (2) Cu/Zn-Mt group: basal diet + 39 mg/kg Cu and 75 mg/kg Zn as Cu/Zn-Mt; (3) Cu + Zn + Mt group: basal diet + mixture of CuSO₄, ZnSO₄, and Mt (equal amount of Cu, Zn, and Mt to the Cu/Zn-Mt group). Each treatment had six pens of six piglets. The results showed that as compared with the control group and the Cu + Zn + Mt group, Cu/Zn-Mt supplementation increased (P < 0.05) the average daily gain and the gain/feed ratio; Cu/Zn-Mt supplementation increased (P < 0.05) the Cu and Zn concentrations in serum, jejunum, and ileum mucosa, villus height, the ratio of villus height to crypt depth, and the activities of SOD, GSH-Px, and IL-10 levels, and decreased the malondialdehyde concentrations in the jejunum and ileum, and intestinal IL-1β, IL-6, and TNF-α levels. Moreover, supplementation with the mixture of CuSO₄, ZnSO₄, and Mt had no effect on the growth performance, but increased the mucosa Cu and Zn concentrations, intestinal morphology, antioxidant capacity, and immune function in the duodenum, while it had no effect on the above indexes in the jejunum and ileum. The results indicated that Mt could be used as a controlled carrier for Cu and Zn, which made Cu/Zn-Mt have better biological activities in the intestine than the mixture of Cu, Zn, and Mt.

Effects of the lipid-coated zinc oxide dietary supplement on intestinal mucosal morphology and gene expression associated with the gut health in weanling pigs challenged with enterotoxigenic Escherichia coli K88

Effects of a lipid-coated zinc oxide (ZnO) Shield Zn® (SZ) vs. ZnO were evaluated. Forty 25-d-old weanling pigs were fed a nursery diet supplemented with 100 mg kg−1 Zn with ZnO (ZnO-100), ZnO-2500, SZ-100, -200, or -400. All piglets were challenged orally with 5 × 108 colony-forming units of enterotoxigenic Escherichia coli K88 on day 7 and euthanized on day 14. The fecal consistency score (FCS) was less for the SZ group vs. ZnO-100 (P < 0.05). The intestinal villus height:crypt depth ratio and goblet cell density were greater for the SZ group vs. ZnO-100. By regression analyses, SZ-100 to -200 and SZ-300 to -400 were comparable to ZnO-2500 in the FCS and intestinal variables, respectively. The jejunal mucosal mRNA level did not differ between the SZ group and either ZnO group in insulin-like growth factor-I and multiple structural proteins and cytokines including zonula occludens protein (ZO) 1 and interleukin (IL) 10 except for lower ZO-1 and IL-10 mRNA levels for the SZ group than for ZnO-2500 and ZnO-100, respectively. The ZO-1 mRNA level regressed positively on the supplemental SZ concentration. Results suggest that SZ play a role in epithelial barrier function and inflammation by modulating the expression of ZO-1 and IL-10.

Effect of diet type and added copper on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs

A total of 757 pigs (PIC 337 × 1050; initially 27.6 kg BW) were used in a 117-d experiment to determine the effects of added Cu from tribasic copper chloride and diet type on growth performance, carcass characteristics, energy digestibility, gut morphology, and mucosal mRNA expression of finishing pigs. Pens of pigs were allotted to 1 of 4 dietary treatments, balanced on average pen weight in a randomized complete block design with 26 to 28 pigs per pen and 7 replications per treatment. Treatments were arranged in a 2 × 2 factorial with main effects of diet type, a corn-soybean meal-based diet (corn-soy) or a high by-product diet (by-product) with 30% distillers dried grains with solubles (DDGS) and 15% bakery meal, and added Cu (0 or 150 mg/kg added Cu). There were no Cu × diet type interactions for growth performance. Overall, neither added Cu nor diet type influenced growth performance. However, caloric efficiency was decreased (P = 0.001) for pigs fed the by-product diet compared to the corn-soy diet. Pigs fed the by-product diet had decreased (P < 0.05) carcass yield and carcass G:F) and marginally decreased (P < 0.07) HCW and carcass ADG compared to pigs fed the corn-soy diet. A Cu × diet type interaction (P < 0.05) existed for DM and GE digestibility during the early finishing period as added Cu improved (P < 0.05) digestibility of DM and GE in the corn-soy diet, but not in the by-product diet. During the late finishing period, added Cu marginally increased (P = 0.060) DM and GE digestibility while pigs fed the by-product diet had decreased DM and GE digestibility (P = 0.001) compared to those fed the corn-soy diet. For gut morphology, pigs fed added Cu had decreased crypt depth (P = 0.017) in the distal small intestine compared to those fed no added Cu. Furthermore, relative mRNA expression of intestinal fatty acid binding protein (iFABP) was decreased (P = 0.032) in pigs fed added Cu compared to those fed no added Cu. In summary, adding 150 mg/kg added Cu or including 30% DDGS and 15% bakery meal into a corn-soy diet did not influence growth performance. However, HCW ADG and HCW G:F were reduced in pigs fed the by-product diet compared to the corn-soy diet. Only minor differences in gut morphology or mRNA expression were observed from feeding diets with high levels of Cu or by-products compared to a corn-soy diet.

Effects of dietary lipid-coated zinc on the antioxidant defense system in the small intestine and liver of piglets

The purpose of the study was to investigate the effects of lipid-coated ZnO (LCZ) and the level of LCZ compared with ordinary zinc oxide (ZnO) on antioxidant defense system in the intestine and liver of piglets. A total of forty piglets (n=8) were fed a diet supplemented with 100 ppm Zn with ZnO (ZnO-1), 2,500 ppm Zn with ZnO (ZnO-2), 100 ppm Zn as LCZ (LCZ-1), 200 ppm Zn as LCZ (LCZ-2), or 400 ppm Zn as LCZ (LCZ-3) for 14-d, respectively. The LCZ-3 group resulted in higher (P<0.05) mRNA expressions and activities of CuZn-superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT), and glutathione S-transferase (GST) in jejunal mucosa compared with the ZnO-1 and LCZ-1 groups, while no difference was observed in the mRNA level of antioxidant genes between the ZnO-1 and ZnO-2 groups. Within the LCZ groups, the LCZ level linearly and quadratically (P<0.01) increased antioxidant enzymes in the jejunum. The maximum response of jejunal antioxidant enzymes to Zn supplementation was achieved by 400 ppm of LCZ. Hepatic mRNA expression of antioxidant enzymes was unaffected by Zn source and level, while hepatic SOD and GST activities were greater (P<0.05) in the LCZ-3 group than in the ZnO-1 group. No difference was observed in lipid peroxidation of the jejunum and liver and the total antioxidant power of plasma among groups. In conclusion, a supplementation with 400 ppm of LCZ resulted in a maximum increase in antioxidant enzymes, indicating that LCZ may affect antioxidant defense system more profoundly than ZnO.

Effects of dietary supplementation of a lipid-coated zinc oxide product on the fecal consistency, growth, and morphology of the intestinal mucosa of weanling pigs

Background

Dietary supplementation of zinc oxide (ZnO) to 2000 to 4000 mg/kg is known to be effective for the prevention and treatment of post-weaning diarrhea in the pig. Such a 'pharmacological' supplementation, however, can potentially result in environmental pollution of the heavy metal, because dietary ZnO is mostly excreted unabsorbed. Two experiments (Exp.) were performed in the present study to determine the effects of a lipid-coated ZnO supplement Shield Zn (SZ) compared with those of ZnO.

Methods

In Exp. 1, a total of 240 21-day-old weanling pigs were fed a diet supplemented with 100 mg Zn/kg as ZnO (ZnO-100), ZnO-2500, SZ-100, or SZ-200 in 24 pens for 14 days on a farm with its post-weaning pigs exhibiting a low incidence of diarrhea. Exp. 2 was performed using 192 24-day-old piglets as in Exp. 1 on a different farm, which exhibited a high incidence of diarrhea.

Results

In Exp. 1, fecal consistency (diarrhea) score (FCS) was less for the ZnO-2500 and SZ-200 groups than for the SZ-100 group (P < 0.05), with no difference between the SZ-100 and ZnO-100 groups. Both average daily gain (ADG) and gain:feed ratio were less for the SZ-200 group than for the ZnO-2500 group, with no difference between the ZnO-100 group and SZ-100 or SZ-200 group. The villus height (VH), crypt depth (CD), and VH:CD ratio of the intestinal mucosa were not influenced by the treatment. In Exp. 2, FCS was lowest for the ZnO-2500 group, with no difference among the other groups. However, neither the ADG nor gain:feed ratio was influenced by the treatment.

Conclusion

Results suggest that physiological SZ supplementation has less beneficial effects than pharmacological ZnO for the alleviation of diarrhea irrespective of its severity and for promoting growth without influencing their integrity of the intestinal mucosal structures with little advantage over physiological ZnO in weanling pigs with a small pen size.

Effects of dietary supplementation of lipid-coated zinc oxide on intestinal mucosal morphology and expression of the genes associated with growth and immune function in weanling pigs

Objective

The present study was conducted to investigate the effects of a lipid-coated zinc oxide (ZnO) supplement Shield Zn (SZ) at the sub-pharmacological concentration on intestinal morphology and gene expression in weanling pigs, with an aim to gain insights into the mechanism of actions for SZ.

Methods

Forty 22-day-old weanling pigs were fed a nursery diet supplemented with 100 or 2,500 mg Zn/kg with uncoated ZnO (negative control [NC] or positive control [PC], respectively), 100, 200, or 400 mg Zn/kg with SZ for 14 days and their intestinal tissues were taken for histological and molecular biological examinations. The villus height (VH) and crypt depth (CD) of the intestinal mucosa were measured microscopically following preparation of the tissue specimen; expression of the genes associated with growth and immune function was determined using the real-time quantitative polymerase chain reaction.

Results

There was no difference in daily gain, gain:feed, and diarrhea score between the SZ group and either of NC and PC. The VH and VH:CD ratio were less for the SZ group vs NC in the jejunum and duodenum, respectively (p<0.05). The jejunal mucosal mRNA levels of insulin-like growth factor (IGF-I) and interleukin (IL)-10 regressed and tended to regress (p = 0.053) on the SZ concentration with a positive coefficient, respectively, whereas the IL-6 mRNA level regressed on the SZ concentration with a negative coefficient. The mRNA levels of IGF-I, zonula occludens protein-1, tumor necrosis factor-α, IL-6, and IL-10 did not differ between the SZ group and either of NC and PC; the occludin and transforming growth factor-β1 mRNA levels were lower for the SZ group than for PC.

Conclusion

The present results are interpreted to suggest that dietary ZnO provided by SZ may play a role in intestinal mucosal growth and immune function by modulating the expression of IGF-I, IL-6, and IL-10 genes.

Excretion of Zinc and Copper Increases in Men during 3 Weeks of Bed Rest, with or without Artificial Gravity

Background: Zinc and copper have many physiologic functions and little or no functional storage capability, so persistent losses of either element present health concerns, especially during extended-duration space missions.Objectives: We evaluated the effects of short-term bed rest (BR), a spaceflight analog, on copper and zinc metabolism to better understand the role of these nutrients in human adaptation to (simulated) spaceflight. We also investigated the effect of artificial gravity on copper and zinc homeostasis.Methods: Zinc and copper balances were studied in 15 men [mean ± SD age: 29 ± 3 y; body mass index (in kg/m2): 26.4 ± 2.2] before, during, and after 21 d of head-down tilt BR, during which 8 of the participants were subjected to artificial gravity (AG) by centrifugation for 1 h/d. Control subjects were transferred onto the centrifuge but were not exposed to centrifugation. The study was conducted in a metabolic ward; all urine and feces were collected. Data were analyzed by 2-factor repeated-measures ANOVA.Results: Urinary zinc excretion values for control and AG groups were 33% and 14%, respectively, higher during BR than before BR, and fecal zinc excretion values for control and AG groups were 36% and 19%, respectively, higher during BR, resulting in 67% and 82% lower net zinc balances for controls and AG, respectively (both P < 0.01), despite lower nutrient intake during BR. Fecal copper values for control and AG groups were 40% and 33%, respectively, higher during BR than before BR (P < 0.01 for both). Urinary copper did not change during BR, but a 19% increase was observed after BR compared with before BR in the AG group (P < 0.05).Conclusions: The increased fecal excretion of copper and zinc by men during BR suggests that their absorption of these minerals from the diet was reduced, secondary to the release of minerals from bone and muscle. These findings highlight the importance of determining dietary requirements for astronauts on space missions and ensuring provision and intake of all nutrients.

Effect of dietary zinc on morphological characteristics and apoptosis related gene expression in the small intestine of Bama miniature pigs

To investigate the effects of dietary zinc (Zn) on small intestinal mucosal epithelium, 6-month-old male Bama miniature pigs were randomly allocated into three groups and treated with three levels of Zn (Control, T1, and T2 diet supplemented with 0, 50, and 1500mg/kg Zn, respectively, as zinc sulfate) for 38days. The samples of small intestine tissues, serum, and feces were collected. The results showed that Zn concentrations of small intestine in the T2 group were higher than those in the control and T1 groups (p<0.05). In the T2 group, the pharmacological dose of dietary Zn treatment caused marked damage to the small intestinal epithelium. The expression of Bax, cleaved caspase-3, and caspase-8 were increased in the duodenum and the jejunum of the T2 group (p<0.05). The mRNA transcript levels of BAX, CYCS and CASP3 genes were upregulated in the duodenum and the jejunum of the T2 group. We concluded that a diet with a pharmacological dose of Zn increased the accumulation of Zn and the expression of Bax, cleaved caspase-3, and caspase-8, which might activate the apoptosis and lead to the marked injury of porcine small intestinal epithelium.

Dietary Zinc Oxide Modulates Antioxidant Capacity, Small Intestine Development, and Jejunal Gene Expression in Weaned Piglets

The current study was conducted to investigate the effects of dietary zinc oxide (ZnO) on the antioxidant capacity, small intestine development, and jejunal gene expression in weaned piglets. Ninety-six 21-day-old piglets were randomly assigned to three dietary treatments. Each treatment had eight replicates with four piglets per replicate. The piglets were fed either control diet (control) or control diet supplemented with in-feed antibiotics (300 mg/kg chlortetracycline and 60 mg/kg colistin sulfate) or pharmacological doses of ZnO (3000 mg/kg). The experiment lasted 4 weeks. Blood samples were collected at days 14 and 28, while intestinal samples were harvested at day 28 of the experiment. Dietary high doses of ZnO supplementation significantly increased the body weight (BW) at day 14 and average daily gain (ADG) of days 1 to 14 in weaned piglets, when compared to control group (P < 0.05). The incidence of diarrhea of piglets fed ZnO-supplemented diets, at either days 1 to 14, days 14 to 28, or the overall experimental period, was significantly decreased in comparison with those in other groups (P < 0.05). Supplementation with ZnO increased the villus height of the duodenum and ileum in weaned piglets and decreased the crypt depth of the duodenum, when compared to the other groups (P < 0.05). Dietary ZnO supplementation decreased the malondialdehyde (MDA) concentration at either day 14 or day 28, but increased total superoxide dismutase (T-SOD) at day 14, when compared to that in the control (P < 0.05). ZnO supplementation upregulated the messenger RNA (mRNA) expression of zonula occludens-1 (ZO-1) and occludin in the jejunum mucosa of weaned piglets, compared to those in the control (P < 0.05). The pro-inflammatory cytokine interleukin-lβ (IL-1β) mRNA expression in the jejunum mucosa was downregulated in the ZnO-supplemented group, compared with the control (P < 0.05). Both in-feed antibiotics and ZnO supplementation decreased the mRNA expression of interferon-γ (IFN-γ), but increased the mRNA expression of transforming growth factor-β (TGF-β), in the jejunum mucosa of piglets, when compared to those in the control (P < 0.05). In summary, supplemental ZnO was effective on the prevention of post-weaning diarrhea (PWD) in weaned piglets and showed comparative growth-promoting effect on in-feed antibiotics, probably by the mechanism of improvement of the antioxidant capacity, restoration of intestinal barrier function and development, and modulation of immune functions.

Metabolomics revealed diurnal heat stress and zinc supplementation-induced changes in amino acid, lipid, and microbial metabolism

Heat stress (HS) dramatically disrupts the events in energy and nutrient metabolism, many of which requires zinc (Zn) as a cofactor. In this study, metabolic effects of HS and Zn supplementation were evaluated by examining growth performance, blood chemistry, and metabolomes of crossbred gilts fed with ZnNeg (no Zn supplementation), ZnIO (120 ppm ZnSO₄), or ZnAA (60 ppm ZnSO₄ + 60 ppm zinc amino acid complex) diets under diurnal HS or thermal‐neutral (TN) condition. The results showed that growth performance was reduced by HS but not by Zn supplementation. Among measured serum biochemicals, HS was found to increase creatinine but decrease blood urea nitrogen (BUN) level. Metabolomic analysis indicated that HS greatly affected diverse metabolites associated with amino acid, lipid, and microbial metabolism, including urea cycle metabolites, essential amino acids, phospholipids, medium‐chain dicarboxylic acids, fatty acid amides, and secondary bile acids. More importantly, many changes in these metabolite markers were correlated with both acute and adaptive responses to HS. Relative to HS‐induced metabolic effects, Zn supplementation‐associated effects were much more limited. A prominent observation was that ZnIO diet, potentially through its influences on microbial metabolism, yielded different responses to HS compared with two other diets, which included higher levels of short‐chain fatty acids (SCFAs) in cecal fluid and higher levels of lysine in the liver and feces. Overall, comprehensive metabolomic analysis identified novel metabolite markers associated with HS and Zn supplementation, which could guide further investigation on the mechanisms of these metabolic effects.

Dietary organic zinc attenuates heat stress-induced changes in pig intestinal integrity and metabolism

Dietary zinc (inorganic and organic or zinc AA complex forms) is essential for normal intestinal barrier function and regeneration of intestinal epithelium. Given that heat stress (HS) exposure can negatively affect intestinal integrity and caloric intake, possible nutritional mitigation strategies are needed to improve health, performance, and well-being. Therefore, our objective was to evaluate 2 dietary zinc sources and reduced caloric intake on intestinal integrity in growing pigs subjected to 12 h of HS. A total of 36 pigs were fed 1 of 2 diets: 1) a control diet (CON; 120 mg/kg of zinc from zinc sulfate) or 2) 60 mg/kg from zinc sulfate and 60 mg/kg from zinc AA complex (ZnAA). After 17 d, the CON pigs were then exposed to thermal neutral (TN) conditions with ad libitum intake (TN-CON), HS (37°C) with ad libitum intake (HS-CON), or pair-fed to HS intake under TN conditions (PFTN); the ZnAA pigs were exposed to only HS (HS-ZnAA). All pigs were sacrificed after 12 h of environmental exposure, and blood and tissue bioenergetics stress markers and ex vivo ileum and colon integrity were assessed. Compared with TN-CON, HS significantly ( < 0.05) increased rectal temperatures and respiration rates. Ileum villus and crypt morphology was reduced by both pair-feeding and HS. Both PFTN and HS-CON pigs also had reduced ileum integrity (dextran flux and transepithelial resistance) compared with the TN-CON pigs. However, ZnAA tended to mitigate the HS-induced changes in ileum integrity. Ileum mucin 2 protein abundance was increased due to HS and pair-feeding. Colonic integrity did not differ due to HS or PFTN treatments. Compared with the HS-CON, HS-ZnAA pigs tended to have reduced blood endotoxin concentrations. In conclusion, HS and reduced feed intake compromised intestinal integrity in pigs, and zinc AA complex source mitigates some of these negative effects.

Effects of zinc sulfate pretreatment on heat tolerance of Bama miniature pig under high ambient temperature

The aim of this study was to evaluate the heat tolerance of Bama miniature pigs under high ambient temperature (40°C) and Zn interactive functions during heat treatment (HT). Bama miniature pigs (male; n = 24; 6-mo old; BW = 10.79 ± 0.06 kg) were randomly allotted to 4 groups and were fed a basal diet or the basal diet supplemented with 1,500 mg of Zn (ZnSO4·H2O)/kg diet for 38 d. At 7 mo of age (d 30), the thermal neutral (TN) groups remained at 25°C, whereas the HT groups were exposed to ambient temperature at 40°C for 5 h daily for 8 consecutive days. Pigs in 4 groups were sacrificed on d 38. Individual rectal temperatures, skin temperatures, and breathing rates were recorded at 3 h after the onset of HT and the blood samples were collected immediately after HT on d 30, 34, and 38. Pigs fed diets with or without Zn doubled their breathing rates (P < 0.05) and increased body surface, scrotal, and rectal temperatures during HT on d 30, 34, and 38, respectively. Zinc supplementation increased BW gain (BWG; P < 0.05) during 38-d experiment period, and HT decreased BWG only from d 30 to 34 (P < 0.05). Heat treatment increased serum testosterone on d 30 (P < 0.05). Zinc supplementation decreased the heat-induced increase of testosterone in HT on d 30 and 34 (P < 0.05). The relative weight of liver increased in HT groups (P < 0.05). Zinc supplementation decreased the relative weights of spleen (P < 0.05) and testis (P < 0.01). The values of abnormal lymphocyte count and large unstained cell count declined approximately 5 times in groups of Zn supplementation, whereas Zn supplementation increased the values of red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, and mean corpuscular hemoglobin. Zinc concentrations increased in serum, liver, kidney, epididymis, longissimus, hair, and feces in groups fed with Zn (P < 0.01). However, additional Zn decreased Zn concentrations in lung, spleen, and testis (P < 0.01). Moreover, HT decreased serum Zn concentrations (P < 0.01). In conclusion, Zn supplementation could be used to alleviate the decline of serum Zn during periods of high ambient temperatures. However, pretreated supplementation with pharmacological Zn did not promote heat tolerance but impacted the erythropoiesis, immunity, and reproductive organ development in Bama miniature pigs.