Organic zinc absorption by the intestine of broilers in vivo

Dietary Dihydromyricetin Zinc Chelate Supplementation Improves the Intestinal Health of Magang Geese

To fulfill the nutritional requirements of poultry, effective Zn supplementation is required due to Zn deficiency in basic feed. In this study, we investigated the effects of DMY-Zn (dihydromyricetin zinc chelate) on the growth performance, morphology, and biochemical indices; the expression of intestinal barrier-related genes; the intestinal microflora; and the cecum metabolome of Magang geese. A total of 300 14-day-old Magang geese (equal number of males and females) with an average body weight of 0.82 ± 0.08 kg were randomly divided into five groups and fed a basal diet; these groups were given DMY-Zn (low, medium, or high level of DMY-Zn with 30, 55, or 80 mg/kg Zn added to the basal diet) or ZnSO4 (80 mg/kg Zn added) for 4 weeks. Our results revealed that DMY-Zn significantly impacts growth and biochemical indices and plays a significant role in regulating the intestinal barrier and microflora. DMY-Zn is involved in the upregulation of intestinal barrier gene (ZO1 and MUC2) expression, as well as upregulated Zn-related gene expression (ZIP5). On the other hand, a low concentration of DMY-Zn increased the ɑ diversity index and the abundance of Lactobacillus and Faecalibacterium. Additionally, a cecal metabolomics study showed that the main metabolic pathways affected by DMY-Zn were the pentose phosphate pathway, the biosynthesis of different alkaloids, and the metabolism of sphingolipids. In conclusion, DMY-Zn can reduce feed intake, increase the expression of intestinal barrier-related genes, help maintain the intestinal microflora balance, and increase the abundance of beneficial bacteria in the intestine to improve intestinal immunity.

Effects of Organic Zinc on the Growth Performance of Weanling Pigs: A Meta-analysis

Supplementation of feed with organic zinc (Zn) has long been discussed as an alternative to inorganic Zn in pigs, but its effects on growth performance are mixed. This meta-analysis was conducted to provide a comprehensive evaluation of the influence of organic Zn on the growth performance of weanling pigs, on the basis of average daily gain (ADG), average daily feed intake (ADFI), and feed to gain ratio (F/G). We screened the PubMed and Web of Science databases (published before December 31, 2022; limited to English) systematically and contrasted organic Zn supplementation with inorganic Zn supplementation. There were 680 retrievals of studies, of which 16 (1389 pigs, 37 records) were eligible to analyze. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated using a random-effects model. The subgroup analysis was classified as organic Zn source (Zn-amino acid (Zn-AA), Zn-glycine (Zn-Gly), Zn-methionine (Zn-Met), Zn-Lysine (Zn-Lys), proteinate complex Zn (Zn-Pro), chitosan-Zn (Zn-CS) or Zn-lactate (Zn-Lac)) and Zn additive dose (low, medium, or high, i.e., lower than, equal to or higher than the requirement of NRC). Organic Zn addition in the weaning phase increased the ADG (P < 0.001) and the ADFI (P = 0.023) and decreased the F/G (P < 0.001). Specifically, for the organic sources, only Zn-CS supplementation presented significant effects on the ADG (P < 0.001), ADFI (P = 0.011), and F/G (P < 0.001). Moreover, medium-dose organic Zn supplementation had positive effects on ADG (P = 0.012), ADFI (P = 0.018), and F/G (P < 0.001). Our results indicate that organic Zn added to diets greatly improves the growth performance of weanling pigs.

Effect of Organic, Nano, and Inorganic Zinc Sources on Growth Performance, Antioxidant Function, and Intestinal Health of Young Broilers

The study aimed to determine the effects of different zinc sources on growth performance, antioxidant function, and intestinal health of broilers. In total, 240 Ross 308 male broilers with similar weight were randomly assigned to 4 treatments, including zinc sulfate, methionine zinc (Zn-Met), glycine zinc (Zn-Gly), and nano-zinc oxide (ZnO-NPs), with 80 mg zinc/kg diet supplementation. The experiment lasted for 21 days. Results showed dietary supplemental Zn-Gly and Zn-Met increased average daily gain during 1-14 days (P = 0.011), and Zn-Gly, Zn-Met, and ZnO-NP supplementation decreased the ratio of feed to gain during 1-21 days (P = 0.003) compared to zinc sulfate. ZnO-NPs supplementation tended to increase total SOD activity (P = 0.068) and had higher serum IgA content and lower MDA level than the other three groups (P < 0.05). Compared with zinc sulfate, Zn-Met and ZnO-NP supplementation decreased TNF-α mRNA expression (P = 0.048). However, serum biochemical indices, intestinal morphology, and mRNA expressions of tight junction proteins were not affected by different zinc sources (P > 0.05). A differential trend was observed in the beta diversity of bacterial communities among four groups (P = 0.082). The LEfSe analysis showed that bacterial genera Blautia, Ruminococcaceae, Clostridia, Anaerostipes, Eubacterium_ventriosum, Merdibacter, and Oscillospira were enriched in the ZnSO4 group, and the genera Eubacterium_hallii and Anaerotruncus were enriched in the Zn-Gly group. The genera UCG-009 and UCG010 were enriched in ZnO-NPs and Zn-Met groups, respectively. It should be stated dietary supplemental Zn-Met improved growth performance, ZnO-NPs promoted IgA production and reduced occurrences of oxidative stress and inflammation, and different zinc sources enriched different jejunal bacteria genera.

Zinc proteinate with moderate chelation strength enhances zinc absorption by upregulating the expression of zinc and amino acid transporters in primary cultured duodenal epithelial cells of broiler embryos

Recent study showed that zinc (Zn) and amino acid transporters may be involved in enhancing Zn absorption from Zn proteinate with moderate chelation strength (Zn-Prot M) in the duodenum of broilers. However, the specific mechanisms by which Zn-Prot M promotes the above Zn absorption are unknown. Therefore, in this study, 3 experiments were conducted to investigate specific and direct effects of Zn-Prot M and Zn sulfate (ZnS) on Zn absorption and expression of related transporters in primary duodenal epithelial cells of broiler embryos so as to preliminarily address possible mechanisms. In experiment 1, cells were treated with 100 μmol Zn/L as ZnS or Zn-Prot M for 20, 40, 60, 80, 100, or 120 min. Experiment 2 consisted of 3 sub-experiments. In experiment 2A, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 100 or 200 μmol Zn/L as ZnS or Zn-Prot M for 60 min; in experiment 2B, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 200 μmol Zn/L of as the ZnS or Zn-Prot M for 120 min; in experiment 2C, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 400 or 800 μmol Zn/L as ZnS or Zn-Prot M for 120 min. In experiment 3, cells were treated with a Zn-unsupplemented basal medium (Control) or the basal medium supplemented with 400 μmol Zn/L as ZnS or Zn-Prot M for 120 min. The results of experiment 1 indicated that the minimum incubation time for saturable Zn absorption was determined to be 50.83 min using the best fit line. The results in experiment 2 demonstrated that a Zn concentration of 400 μmol/L and an incubation time of 120 min were suitable to increase the absorption of Zn from Zn-Prot M compared to ZnS. In experiment 3, Zn absorption across cell monolayers was significantly increased by Zn addition (P < 0.05), and was significantly greater with Zn-Prot M than with ZnS (P < 0.05). Compared to the control, Zn addition significantly decreased Zn transporter 10 and peptide-transporter 1 mRNA expression levels and increased y + L-type amino transporter 2 (y + LAT2) protein abundance (P < 0.05). Moreover, protein expression levels of zrt/irt-like protein 3 (ZIP3), zrt-irt-like protein 5 (ZIP5), and y + LAT2 were significantly greater for Zn-Prot M than for ZnS (P < 0.05). These findings suggest that Zn-Prot M promote Zn absorption by increasing ZIP3, ZIP5 and y + LAT2 protein expression levels in primary duodenal epithelial cells.

Effect of In Ovo Administration of a Multi-Strain Probiotic and Zinc Glycine Chelate on Antioxidant Capacity and Selected Immune Parameters in Newly Hatched Chicks

The aim of this study was to determine the effect of in ovo co-supplementation of chicken embryos with a multi-strain probiotic containing effective microorganisms and zinc glycine chelate on total antioxidant capacity; concentrations of sulfhydryl groups, bityrosine bridges, formylkynurenines, hydroperoxides, proteins, corticosterone, pro- and anti-inflammatory cytokines and heat shock proteins; and the activity of catalase and superoxide dismutase in the serum, yolk sac and tissues of broiler chickens at 12 h and at 7 days after hatching. The results indicate high SOD activity in the small and large intestines of chicks at 12 h post-hatch in the groups receiving the multi-strain probiotic and in the small intestine and yolk sac of birds receiving the multi-strain probiotic and Zn-Gly chelate. High concentrations of TNF-α and IFN-γ in the yolk sac and serum after in ovo administration of Zn-Gly chelate were observed 12 h after hatching. The use of a probiotic and a probiotic with Zn-Gly chelate increased the total antioxidant capacity in the tissues of chickens. It can be concluded that in ovo administration of a multi-strain probiotic and Zn-Gly chelate can maintain the oxidant/antioxidant balance in chickens and increase the defense capacity against oxidative stress.

Early supplementation with zinc proteinate does not change rectal microbiota but increases growth performance by improving antioxidant capacity and plasma zinc concentration in preweaned dairy calves

The present study evaluated the effects of early supplementation with zinc proteinate (ZnP) or zinc oxide (ZnO) for 2 weeks on the growth performance, redox status, plasma trace element concentrations, and rectal microbiota of preweaned dairy calves. A total of 60 newborn healthy female Holstein dairy calves, with initial body weight (BW): 41.33 ± 0.62 kg, were randomly allocated to 5 groups of 12 each: a control group (CON); three groups supplemented with 261 (L-ZnP), 523 (M-ZnP), and 784 (H-ZnP) mg/day ZnP, equivalent to 40, 80, and 120 mg/day zinc, respectively; and one group supplemented with 232 mg/day ZnO, equivalent to 180 mg/day zinc (ZnO). Zinc supplements were administered on days 1-14, and the calves were followed up until day 70. Zinc supplementation increased total dry matter intake (DMI) and starter DMI compared with the CON group (p < 0.01). The final BW, average daily gain, and feed efficiency were higher in the M-ZnP, H-ZnP, and ZnO groups (p < 0.05). The incidence of diarrhea on days 1-28 was reduced by zinc administration (p < 0.01), whereas the incidence on days 29-56 was lower in the M-ZnP and ZnO groups (p < 0.05). Serum glutathione peroxidase activity, total antioxidant capacity, immunoglobulin G and plasma zinc concentrations were increased linearly (p < 0.05), while the serum concentration of malondialdehyde was decreased linearly (p < 0.01), as the dose of ZnP increased. ZnP yielding 80 mg/day zinc had similar effects as ZnO yielding 180 mg/day zinc, except that final BW was higher in the ZnO group (p < 0.05). At the phylum level, ZnO decreased the relative abundance of Firmicutes while increasing the abundance of Bacteroidetes (p < 0.05). At the genus level, ZnO increased the relative abundances of Prevotella, Subdoligranulum, and Odoribacter (p < 0.05). These findings indicated that early supplementation with ZnP did not affect the rectal microbiota of preweaned dairy calves but increased their growth performance, antioxidant capacity, and plasma zinc concentration. In summary, ZnP is an organic zinc source with greater bioavailability than ZnO for preweaned dairy calves. Early dietary supplementation with ZnP yielding 80 mg/day zinc is recommended.

The Effects of Zinc Supplementation on Growth, Diarrhea, Antioxidant Capacity, and Immune Function in Holstein Dairy Calves

The current study examined the effects of supplementary zinc proteinate (ZnPro) and zinc oxide (ZnO) on growth performance, diarrhea, antioxidant capacity, immune function, and mineral element concentrations of calves aged 1 to 28 days. A total of twenty-four newborn calves were divided randomly into 3 groups (n = 8; 2 males and 6 females per group), and each received: 0 mg/d Zn (CON), 627 mg/d ZnPro (80 mg/d Zn; ZnPro group), and 101 mg/d ZnO (80 mg/d Zn; ZnO group). The calves received the additive in their milk during the first 28 days of life. Compared with the CON group: ZnPro and ZnO improved average daily gain (ADG) and decreased the feed:gain ratio (FGR) between days 1 and 14 (p < 0.05), while the ADG increased and FGR decreased only in the ZnPro group between days 1 and 28 (p < 0.05). The incidence of diarrhea decreased (p < 0.05) in the ZnPro and ZnO groups between days 15 and 28 as well as days 1 and 28, but decreased (p < 0.05) only in the ZnPro group between days 1 and 14. The serum immunoglobulin G (IgG) concentration of the ZnPro and ZnO groups increased on days 14 and 28 (p < 0.05). ZnPro supplementation increased serum IgM concentration during the whole study, while ZnO enhanced serum IgM concentration only on day 14 (p < 0.05). In the ZnO group, the serum concentration of cytokines interleukin (IL)-10 increased on day 14, while that of IL-1β increased on day 28 (p < 0.05). In addition, ZnPro reduced the serum malondialdehyde (MDA) concentration on days 14 and 28 (p < 0.05). Both ZnPro and ZnO increased the serum concentrations of alkaline phosphatase (ALP) and metallothionein (MT) on day 14 (p < 0.05). With zinc supplementation, plasma Zn concentration increased (p < 0.05) on days 14 and 28 of age. We concluded that supplementary ZnPro and ZnO reduced incidences of diarrhea and promoted the immune function, but ZnPro improved the growth performance and antioxidant capacity of Holstein dairy calves to a greater extent.

The organic zinc with moderate chelation strength enhances the expression of related transporters in the jejunum and ileum of broilers

Our previous study demonstrated that the zinc (Zn) proteinate with moderate chelation strength (Zn-Prot M) enhanced the Zn absorption in the small intestine partially via increasing the expression of some Zn and amino acid transporters in the duodenum of broilers. However, it remains unknown whether the Zn-Prot M could also regulate the expression of related transporters in the jejunum and ileum of broilers in the above enhancement of Zn absorption. The present study was conducted to investigate the effect of the Zn-Prot M on the expression of related transporters in the jejunum and ileum of broilers compared to the Zn sulfate (ZnS). Zinc-deficient broilers (13-d-old) were fed with the Zn-unsupplemented basal diets (control) or the basal diets supplemented with 60 mg Zn/kg as ZnS or Zn-Prot M for 26 d. The results showed that in the jejunum, compared to the control, supplementation of the organic or inorganic Zn increased (P < 0.05) mRNA and protein expression of b^0,+-type amino acid transporter (rBAT), Zn transporter 10 (ZnT10), and peptide-transporter 1 (PepT1) mRNA expression and Zn transporter 7 (ZnT7) protein expression on d 28, while y+L-type amino transporter 2 (y+LAT2) mRNA and protein expression, and protein expression of ZnT7 and ZnT10 on 28 d and zrt-irt-like protein 3 (ZIP3) and zrt-irt-like protein 5 (ZIP5) on d 39 were higher (P < 0.05) for Zn-Prot M than for ZnS. In the ileum, Zn addition regardless of Zn source up-regulated (P < 0.05) mRNA expression of Zn transporter 9 (ZnT9) and ZIP3, ZIP5, and y+LAT2 protein expression on d 28, and PepT1 mRNA and protein expression, ZIP3 and y+LAT2 mRNA expression and ZnT10 protein expression on d 39. Furthermore, Zn transporter 4 (ZnT4) and ZnT9 mRNA expression and Zn transporter 1 (ZnT1) protein expression on d 28, and y+LAT2 mRNA expression and ZnT10 and PepT1 protein expression on d 39 were higher (P < 0.05) for Zn-Prot M than for ZnS. It was concluded that the Zn-Prot M enhanced the expression of the ZnT1, ZnT4, ZnT9, ZnT10, ZIP3, ZIP5, y+LAT2, and PepT1 in the jejunum or ileum of broilers compared to the ZnS.

Comparison of plant extract-derived nano-zinc particles with different zinc sources and effects of different Zn sources on egg yield and quality traits

This study aimed to compare the zinc (Zn) nanoparticles obtained from plant extracts with different zinc sources and to reveal the effects of different Zn sources on growth performance, egg quality traits and blood serum parameters of laying quail. Treatment groups as follows: control and 3 and 6 mg/kg inorganic, organic, and plant extract-derived nano-Zn particles to quail diet supplementation. Animals were fed on experimental diets for 6 weeks. Different Zn sources supplemented into quail diets did not significantly affect live weights (P > 0.05). On the other hand, different Zn sources increased egg yields (P < 0.05). Plant extract-derived nano-Zn supplementations into quail diets increased feed consumption, feed conversion ratio, and egg weights (P < 0.05). However, 6 mg/kg plant extract-derived nano-Zn supplementations reduced egg weights. Different Zn sources did not have any significant effects on egg yolk weight (g) and egg yolk color L*b* values (P > 0.05). For blood serum parameters, 6 mg/kg plant extract-derived nano-Zn supplementations increased blood serum AST, ALT, and Zn values (P < 0.05). No adverse effect was observed on the measured values in laying Japanese quails. The findings suggest that plant extract-derived nano-Zn particles could reliably be used in quail feeding.

Effects of Zinc Glycinate on Growth Performance, Serum Biochemical Indexes, and Intestinal Morphology of Yellow Feather Broilers

The purpose of this study was to investigate the effects of zinc glycinate (Gly-Zn) on growth performance, serum biochemical index, intestinal morphology, and hepatic metallothionein (MT) mRNA expression in the liver of yellow feather broilers. A total of 540 18-day-old yellow feather broilers were randomly divided into three groups: control group (basal diet), ZnSO4 group (basal diet plus 60 mg Zn/kg from ZnSO4), and Gly-Zn group (basal diet plus 60 mg Zn/kg from zinc glycinate). Each treatment group had 6 replicates with 30 birds in each replicate. The experiment lasted for 42 days (18 to 59 days of age). The results showed that Gly-Zn supplementation significantly improved the average daily gain (ADG) and average daily feed intake (ADFI) of broilers during 18 to 39 days of age compared with that in the control group (P < 0.05) but not different from the ZnSO4 group. The Gly-Zn group had higher glutathione peroxidase (GSH-Px) (P < 0.05) and lower malondialdehyde (MDA) concentrations than the broilers in the control and ZnSO4 group. It was also observed that zinc content in the tibia of Gly-Zn group broilers was higher than the control and ZnSO4 group (P < 0.05). The results of intestinal morphology parameters showed that the Gly-Zn group significantly increased the villus height in duodenum and jejunum (P < 0.05) and decreased crypt depth in duodenum and ileum compared to the control group. However, there were no significant differences between the Gly-Zn group and ZnSO4 group in duodenum and ileum regarding intestinal morphology parameters. The Gly-Zn group significantly increased mRNA expression of MT in the liver than both control and ZnSO4 groups (P < 0.05). Collectively, the results indicated that supplementing 60 mg Zn/kg through zinc glycinate improved growth performance and serum indexes as well as intestinal morphology of yellow feather broilers. It also regulates MT gene expression more effectively than the ZnSO4 group at the transcriptional level.

Mechanisms Underlying the Protective Effect of Maternal Zinc (ZnSO4 or Zn-Gly) against Heat Stress-Induced Oxidative Stress in Chicken Embryo

Environmental factors such as high temperature can cause oxidative stress and negatively affect the physiological status and meat quality of broiler chickens. The study was conducted to evaluate the effects of dietary maternal Zn-Gly or ZnSO4 supplementation on embryo mortality, hepatocellular mitochondrial morphology, liver antioxidant capacity and the expression of related genes involved in liver oxidative mechanisms in heat-stressed broilers. A total of 300 36-week-old Lingnan Yellow broiler breeders were randomly divided into three treatments: (1) control (basal diet, 24 mg zinc/kg); (2) inorganic ZnSO4 group (basal diet +80 mg ZnSO4/kg); (3) organic Zn-Gly group (basal diet +80 mg Zn-Gly/kg). The results show that maternal zinc alleviated heat stress-induced chicken embryo hepatocytes’ oxidative stress by decreasing the content of ROS, MDA, PC, 8-OHdG, and levels of HSP70, while enhancing T-SOD, T-AOC, CuZn-SOD, GSH-Px, CTA activities and the content of MT. Maternal zinc alleviated oxidative stress-induced mitochondrial damage in chick embryo hepatocytes by increasing mitochondrial membrane potential and UCP gene expression; and Caspase-3-mediated apoptosis was alleviated by increasing CuZn-SOD and MT gene expression and decreasing Bax gene expression and reducing the activity of caspase 3. Furthermore, maternal zinc treatment significantly increased Nrf2 gene expression. The results above suggest that maternal zinc can activate the Nrf2 signaling pathway in developing chick embryos, enhance its antioxidant function and reduce the apoptosis-effecting enzyme caspase-3 activities, thereby slowing oxidative stress injury and tissue cell apoptosis.

Organic zinc with moderate chelation strength enhances zinc absorption in the small intestine and expression of related transporters in the duodenum of broilers

Our previous study demonstrated that the absorption of zinc (Zn) from the organic Zn proteinate with moderate chelation strength was significantly higher than that of Zn from the inorganic Zn sulfate in the in situ ligated duodenal segment of broilers, but the underlying mechanisms are unknown. The present study aimed to determine the effect of organic Zn with moderate chelation strength and inorganic Zn on the Zn absorption in the small intestine and the expression of related transporters in the duodenum of broilers. The Zn-deficient broilers (13 days old) were fed with the Zn-unsupplemented basal diets (control) containing 25.72 and 25.64 mg Zn/kg by analysis or the basal diets supplemented with 60 mg Zn/kg as the Zn sulfate or the Zn proteinate with moderate chelation strength (Zn-Prot M) for 26 days. The results showed that the plasma Zn contents from the hepatic portal vein of broilers at 28 days and 39 days of age were increased (p < 0.05) by Zn addition and greater (p < 0.05) in the Zn-Prot M than in the Zn sulfate. On d 28, Zn addition upregulated (p < 0.05) mRNA expression of zinc transporter 1 (ZnT1), Zrt-irt-like protein 5 (ZIP5), y + L-type amino transporter 2 (y + LAT2) and b^0,+-type amino acid transporter (rBAT), zinc transporter 4 (ZnT4) protein expression, and zinc transporter 9 (ZnT9) mRNA and protein expression in the duodenum. Moreover, ZnT9 mRNA expression, ZnT4, ZIP5, and rBAT protein expression, zinc transporter 7 (ZnT7), and y + LAT2 mRNA and protein expression in the duodenum of broilers on 28 days were higher (p < 0.05) in the Zn-Prot M than in the Zn sulfate. On d 39, supplemental Zn increased (p < 0.05) peptide-transporter 1 (PepT1) mRNA expression and y + LAT2 protein expression, while the mRNA expression of ZnT7 and Zrt-irt-like protein 3 (ZIP3) were higher (p < 0.05) for the Zn-Prot M than for the Zn sulfate in the duodenum. It was concluded that the Zn-Prot M enhanced the Zn absorption in the small intestine partially via upregulating the expression of ZnT4, ZnT7, ZnT9, ZIP3, ZIP5, y + LAT2, and rBAT in the duodenum of broilers.

Effect of Dietary Zinc Methionine Supplementation on Growth Performance, Immune Function and Intestinal Health of Cherry Valley Ducks Challenged With Avian Pathogenic Escherichia coli

This study was carried out to evaluate the effects of supplemental zinc methionine (Zn-Met) on growth performance, immune function, and intestinal health of meat ducks challenged with avian pathogenic Escherichia coli (APEC). A total of 480 1-day-old Cherry Valley male ducks were randomly assigned to 8 treatments with 10 replicates, each replicate containing 10 ducks. A 4 × 2 factor design was used with four dietary zinc levels (0, 30, 60, 120 mg Zn/kg in the form Zn-Met was added to the corn-soybean basal diet) and challenged with or without APEC at 8-days-old ducks. The trial lasted for 14 days. The results showed that a dietary Zn-Met supplementation significantly increased body weight (BW) of 14 days and BW gain, and decreased mortality during 7-14-days-old ducks (p < 0.05). Furthermore, dietary 30, 60, 120 mg/kg Zn-Met supplementation noticeably increased the thymus index at 2 days post-infection (2 DPI) and 8 DPI (p < 0.05), and 120 mg/kg Zn-Met enhanced the serum IgA at 2 DPI and IgA, IgG, IgM, C3 at 8 DPI (p < 0.05). In addition, dietary 120 mg/kg Zn-Met supplementation dramatically increased villus height and villus height/crypt depth (V/C) of jejunum at 2 DPI and 8 DPI (p < 0.05). The TNF-α and IFN-γ mRNA expression were downregulated after supplemented with 120 mg/kg Zn-Met in jejunum at 8 DPI (p < 0.05). Moreover, dietary 120 mg/kg Zn-Met supplementation stimulated ZO-3, OCLN mRNA expression at 2 DPI and ZO-2 mRNA expression in jejunum at 8 DPI (p < 0.05), and improved the MUC2 concentration in jejunum at 2 DPI and 8 DPI (p < 0.05). At the same time, the cecal Bifidobacterium and Lactobacillus counts were increased (p < 0.05), and Escherichia coli counts were decreased (p < 0.05) after supplemented with Zn-Met. In conclusion, inclusion of 120 mg/kg Zn-Met minimizes the adverse effects of APEC challenge on meat ducks by improving growth performance and enhancing immune function and intestinal health.

Tolerance and safety evaluation of L-glutamic acid, N,N-diacetic acid as a feed additive in broiler diets

The novel chelator, L-glutamic acid, N,N-diacetic acid (GLDA) can be used as a dietary ingredient to safely reduce Zn supplementation in complete feed, without compromising the Zn status of farm animals. The objective of this study was to study dietary tolerance, bioaccumulation, and evaluate the safety of GLDA when supplemented in broiler diets at 0, 100, 300, 1000, 3,000, and 10,000 mg/kg. A total of 480 one-day-old Ross 308 male broilers were randomly allocated to 48 pens and fed one of the 6 experimental diets. Production performance was used to assess tolerance to the additive. At trial end, toxicity was evaluated using hematology, plasma biochemistry (n = 144) and gross necropsy (n = 48). Residue levels of GLDA were assessed in liver, kidney and breast tissue of birds used for necropsy. Performance showed an increase (P < 0.05) in body weight for GLDA inclusion at 300 mg/kg. A decrease on the measured performance parameters was found for the 10,000 mg/kg GLDA inclusion level (P < 0.05). The additive was added as a tetra-sodium salt, leading to sodium levels being 2.5 times higher in the latter treatment compared to the control diet which may have led to impaired intestinal barrier function. Mortality was not different between treatments. Residue levels for GLDA at the highest inclusion indicate that 0.0005% of total GLDA consumption is accumulated in breast tissue. Higher values of GLDA were found in kidney and liver at the highest inclusion level, potentially confirming that the small fraction of GLDA absorbed was readily excreted by the animal. At 100 and 300 mg/kg GLDA inclusion there were negligible amounts of GLDA present in all tissues measured. The present experiment demonstrated a high dietary tolerance to GLDA in broilers and indicated that GLDA does not pose a significant risk to food safety when supplemented below 3,000 mg/kg.

Zinc alleviates the heat stress of primary cultured hepatocytes of broiler embryos via enhancing the antioxidant ability and attenuating the heat shock responses

Zinc (Zn) has been shown to attenuate the adverse effects of heat stress on broilers, but the mechanisms involving this process remain unclear. We aimed to investigate possible protective mechanisms of Zn on primary cultured hepatocytes of broiler embryos subjected to heat stress. Three experiments were conducted. In Exp. 1, hepatocytes were treated with 0, 50, 100, 200, or 400 μmol/L added Zn as inorganic Zn sulfate (iZn) for 12, 24 or 48 h. In Exp. 2, cells were exposed to 40 °C (a normal temperature [NT]) and 44 °C (a high temperature [HT]) for 1, 2, 4, 6, or 8 h. In Exp. 3, cells were preincubated with 0 or 50 μmol/L Zn as iZn or organic Zn lysine chelate (oZn) for 8 h under NT, and then incubated with the same Zn treatments under NT or HT for 4 or 6 h. The biomarkers of antioxidative status and heat stress in cells were measured. The results in Exp. 1 indicated that 50 μmol/L Zn and 12 h incubation were the optimal conditions for increasing antioxidant ability of hepatocytes. In Exp. 2, the 4 or 6 h incubation under HT was effective in inducing heat shock responses of hepatocytes. In Exp. 3, HT elevated (P < 0.01) malondialdehyde content and expressions of heat shock protein 70 (HSP70) mRNA and protein, as well as HSP90 mRNA. However, Zn supplementation increased (P < 0.05) copper zinc superoxide dismutase (CuZnSOD) activity and metallothionein mRNA expression, and effectively decreased (P < 0.05) the expressions of HSP70 mRNA and protein, as well as HSP90 mRNA. Furthermore, oZn was more effective (P < 0.05) than iZn in enhancing CuZnSOD activity of hepatocytes under HT. It was concluded that Zn (especially oZn) could alleviate heat stress of broiler hepatocytes via enhancing their antioxidant ability and attenuating heat shock responses.

Organic iron absorption and expression of related transporters in the small intestine of broilers

An experiment was conducted to investigate the effect of organic and inorganic Fe sources on Fe absorption and expression of related transporters in the small intestine of broilers. Iron-deficient intact broilers (7-day-old) were fed an Fe-unsupplemented corn-soybean meal basal diet or the basal diet supplemented with 60 mg Fe/kg as Fe sulfate (FeSO₄•7H₂O), Fe-Met with weak chelation strength (Fe-Met W), Fe-proteinate with moderate chelation strength (Fe-Prot M) or Fe-proteinate with extremely strong chelation strength (Fe-Prot ES) for 14 d. The plasma Fe contents were enhanced (P < 0.02) by Fe addition, and greater (P < 0.0002) in Fe-Prot M and Fe-Prot ES groups than in Fe-Met W and FeSO₄ groups. Supplemental Fe decreased (P < 0.03) the divalent metal transporter 1 (DMT1) mRNA levels in the duodenum and jejunum, and ferroportin 1 (FPN1) mRNA levels in the duodenum on d 21, but no differences (P > 0.20) were detected among different Fe sources. Regardless of Fe source, the mRNA levels of DMT1 and FPN1 were higher (P < 0.02) in the duodenum than in the jejunum and ileum, and in the jejunum than in the ileum (P < 0.05). However, Fe addition did not affect (P > 0.10) the mRNA levels of amino acid transporters and protein levels of DMT1 and FPN1 in the small intestine of broilers. These results indicate that organic Fe sources with stronger chelation strength showed higher Fe absorption in broilers in vivo; the mRNA expression of Fe and amino acid transporters varied along with the extension of the small intestine; the absorption of Fe as organic Fe chelates was not mediated by the amino acid transporters in intact chicks in this study.

Efficacy of Adjunctive Zinc in Improving the Treatment Outcomes in Hospitalized Children with Pneumonia: A Randomized Controlled Trial

BACKGROUND

The mortality rate of pneumonia is high, placing a huge burden on developing countries. Healthcare professionals use zinc as an adjunctive treatment for children with pneumonia; however, this contradicts with some published reports. Thus, this study aimed to assess the efficacy of zinc supplementation on the treatment outcomes of pneumonia.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted on hospitalized children with pneumonia. The children randomly received either zinc bis-glycinate (15 mg elemental zinc) or placebo, twice per day. The primary outcome was the resolution time of pneumonia, and the secondary outcomes were the duration of hospitalization and the recovery times of each clinical symptom.

RESULTS

Out of the 91 children, 65 (71.4%) were males. The resolution period of clinical pneumonia was significantly shorter in the zinc group than the placebo group (48 and 72 h, respectively; hazard ratio = 0.585, 95% confidence interval 0.377-0.908). Similarly, the hospitalization period and the resolution period of fever were shorter in the zinc group [96 and 144 h (p = 0.008), and 24 and 42 h (p = 0.002), respectively]. Children receiving zinc needed a median of 28 h to reach the normal level of oxygen saturation compared to 48 h required by children under placebo (p = 0.014).

CONCLUSION

Zinc supplementation enhanced the treatment outcomes of pneumonia, by reducing the resolution period of pneumonia and normalizing oxygen levels and body temperature. The length of hospital stay for children receiving zinc was shorter than those receiving placebo.

Effect of the Source of Zinc on the Tissue Accumulation of Zinc and Jejunal Mucosal Zinc Transporter Expression in Holstein Dairy Calves

Simple Summary

Diarrhea is the main cause of death in newborn calves and is associated with antibiotic use and economic loss for dairy farms. In this study, we evaluated the effects of different sources of the mineral zinc (zinc oxide (ZnO) and zinc methionine (Zn-Met)) on the growth, incidence of diarrhea, tissue zinc accumulation, gene expression of jejunal zinc transporters and serum concentrations of zinc-dependent proteins in newborn Holstein dairy calves. We found that Zn-Met supplementation promoted growth and reduced diarrhea from the second week after birth. It also increased the levels of zinc in the serum and liver, the level of the transporter protein ZIP4 in the jejunal mucosa, as well as the serum alkaline phosphatase and metallothionein concentrations compared to the control group. ZnO supplementation had similar but less marked effects to Zn-Met supplementation. These results suggest that Zn-Met supplementation may be an alternative to antibiotics for the treatment of newborn calf diarrhea.

Abstract

Zinc is considered to be an anti-diarrheal agent, and it may therefore reduce the incidence of diarrhea in young calves. In the present study, we aimed to compare the effect of zinc source on growth performance, the incidence of diarrhea, tissue zinc accumulation, the expression of zinc transporters, and the serum concentrations of zinc-dependent proteins in neonatal Holstein dairy calves. Eighteen male newborn Holstein dairy calves were fed milk and starter diet supplemented with or without 80 mg zinc/d in the form of Zn-Met or ZnO for 14 days, and were then euthanized. Zn-Met supplementation improved average daily gain and feed efficiency, and reduced the incidence of diarrhea, compared with control calves (p < 0.05). It also increased the serum and hepatic zinc concentrations and the mRNA expression of the ZIP4 transporter in the jejunal mucosa of the calves (p < 0.05). In addition, the serum alkaline phosphatase activity and metallothionein concentration were higher in Zn-Met-treated calves than in control calves (p < 0.05). ZnO supplementation had similar effects, but these did not reach significance. Thus, Zn-Met supplementation is an effective means of increasing tissue zinc accumulation and jejunal zinc absorption, and can be used as an anti-diarrheal strategy in neonatal calves.

The Effect of Multispecies Probiotic Supplementation on Iron Status in Rats

A range of interactions between gut microbiota and iron (Fe) metabolism is described. Oral probiotics ameliorate host's iron status. However, this has been proven for single-strain probiotic supplements. Dose-dependence of beneficial probiotic supplementation effect on iron turnover remains unexplored. Our study aimed to investigate the effects of oral multispecies probiotic supplementation in two doses on iron status in rats. Thirty rats were randomized into three groups receiving multispecies probiotic supplement at a daily dose of 2.5 × 10⁹ CFU (PA group, n = 10) and 1 × 10¹⁰ CFU (PB group, n = 10) or placebo (KK group, n = 10). After 6 weeks, rats were sacrificed for analysis, blood samples, and organs (the liver, heart, kidneys, spleen, pancreas, femur, testicles, duodenum, and hair) were collected. The total fecal bacteria content was higher in the PB group vs. PA group. Unsaturated iron-binding capacity was higher in the PB group vs. KK group. Serum Fe was lower in both PA and PB vs. KK group. Iron content in the liver was higher in the PB group vs. KK group; in the pancreas, this was higher in the PB group vs. the KK and PA group, and in the duodenum, it was higher in both supplemented groups vs. the KK group. A range of alterations in zinc and copper status and correlations between analyzed parameters were found. Oral multispecies probiotic supplementation exerts dose-independent and beneficial effect on iron bioavailability and duodenal iron absorption in the rat model, induces a dose-independent iron shift from serum and intensifies dose-dependent pancreatic and liver iron uptake.

Effects of environmental temperature and dietary zinc on egg production performance, egg quality and antioxidant status and expression of heat-shock proteins in tissues of broiler breeders

To investigate the effects of environmental temperature and dietary Zn on egg production performance, egg quality and antioxidant status, as well as expression of heat-shock proteins (HSP) in tissues, of laying broiler breeders, we used a completely randomised design with a 2×3 factorial arrangement of treatments. The two environmental temperatures were normal (21±1°C, NT) and high (32±1°C, HT). The three dietary Zn sources were a Zn-unsupplemented basal diet (CON), and the basal diet supplemented with 110 mg Zn/kg as either the inorganic Zn sulphate (iZn) or the organic Zn proteinate with a moderate chelation strength (oZn). HT decreased (P<0·002) egg weight, laying rate, eggshell strength, thickness and weight, but increased (P≤0·05) rectal temperature, broken egg rate, misshapen egg rate, feed:egg ratio, Cu Zn superoxide dismutase activities in liver and pancreas, as well as metallothionein (MT) level in pancreas, and HSP70 mRNA levels in liver and pancreas of laying broiler breeders. Broiler breeders fed the oZn diet had higher (P<0·04) Zn content in the liver, as well as MT levels in the liver and pancreas, compared with those fed the CON diet. Under HT, broiler breeders fed the oZn diet had higher (P<0·05) Zn content in the pancreas compared with those fed the iZn and CON diets. The results from this study indicated that HT impaired egg production performance and eggshell quality possibly because of the disturbed redox balance and HSP homoeostasis, whereas the oZn is more available than the iZn for pancreatic Zn of heat-stressed laying broiler breeders.

A randomized controlled trial of zinc supplementation in the treatment of acute respiratory tract infection in Thai children

Acute Lower Respiratory Tract Infections (ALRI) are one of the most common causes of morbidity and mortality in young children. Zinc supplementation has been shown to have a preventive effect against respiratory infections, but little evidence is available on its effect on the treatment of ALRI. This study examined the effect of zinc supplementation on the treatment outcome in children that were hospitalized with ALRI. A randomized, doubleblinded, placebo-controlled trial was conducted on 64 hospitalized children with ALRI, who were aged between 2 and 60 months. Children were randomly allocated to receive zinc (30 mg elemental zinc/day) or placebo. The primary outcome was the time to the cessation of ALRI, while the secondary outcomes were the length of the stay in hospital and the individual features of the disease. The study found that ALRI cessation was faster in children who received zinc supplementation (median (IQR): 3 (2-4) days and 4 (3-5) days, respectively; P=0.008), and that their hospital stay was shorter (mean (SD): 3.8 (1.3) days and 6.1 (3.2) days, respectively; P<0.001) than the placebo group. Zinc supplementation was well-tolerated, and no adverse events were reported. In conclusion, zinc supplementation reduced the number of days of ALRI in Thai children, as well as their stay in hospital.

Zinc source modulates intestinal inflammation and intestinal integrity of broiler chickens challenged with coccidia and Clostridium perfringens

Two dietary sources of zinc (ZnSO4 or organic Zn) were tested in chickens challenged with coccidiosis (Co) or coccidiosis plus Clostridium perfringens (CoCPF). On day 14, the chickens were orally gavaged with ∼5,000 Eimeria maxima sporulated oocysts. On day 19, 20, and 21 chickens challenged with C. perfringens were given a broth culture containing 108 cfu of this bacterium. Productive performance parameters were determined at d 14, 21, and 28. On day 21, necrotic enteritis (NE) lesions were scored, and intestinal permeability was evaluated. Jejunum and cecal tonsils were collected for morphology and gene expression analysis. On day 21, organic Zn improved BW gain by 18.6% (P = 0.07), and FCR by 12% (P = 0.09) in CoCPF challenged chickens vs. birds fed ZnSO4. From 1 to 28, organic Zn increased BW gain (P = 0.02), and improved FCR (P = 0.03) vs. birds fed ZnSO4. At 21 d, NE lesions were only observed in CoCPF birds (P < 0.001), and mortality due to NE was only observed when CoCPF birds were fed ZnSO4 (P = 0.001). Organic Zn fed birds had increased villus height in the jejunum (P = 0.005) and decreased intestinal permeability (P = 0.01) vs. ZnSO4. In the jejunum, organic Zn fed birds showed a downregulation of expression of IL-8 (P = 0.02), and upregulation of IL-10 (P = 0.05) in CoCPF birds vs. ZnSO4- CoCPF birds. As main effect, birds supplemented with organic Zn had higher mRNA expression of TLR-2 (P = 0.02) and IgA (P = 0.01). In the cecal tonsils, organic Zn fed birds showed upregulation of iNOS (P = 0.008) in CoCPF birds vs. ZnSO4-CoCPF birds. Organic Zn supplementation reduced intestinal permeability and attenuated intestinal inflammation of broilers co-challenged with coccidia and C. perfringens.

Association between the gut microbiota and mineral metabolism

The aim of this review is to present the most recent scientific evidence of interactions between the intestinal microbiota and minerals, and the effect of this interaction on the health of the host. The Web of Science database from the years 2013-2017 on this topic was reviewed. Numerous in vitro studies have shown that iron significantly affects the intestinal microbiota. However, Bifidobacteriaceae are capable of binding iron in the large intestine, thereby limiting the formation of free radicals synthesized in the presence of iron, and thus reducing the risk of colorectal cancer. Animal studies have revealed that supplementation with probiotics, prebiotics and synbiotics has a significant effect on bone calcium, phosphate and bone metabolism. The dynamic interaction between microbiota and zinc was shown. Human studies have provided evidence of the influence of probiotic bacteria on parathormone, calcium and phosphate levels and thus on bone resorption. Recent studies have produced new information mainly on the impact of the intestinal bacteria on the metabolism of calcium and iron. From a scientific perspective, the most urgent fields that remain to be investigated are the identification of all human gut microbes and new therapies targeting the interaction between intestinal bacteria and minerals. © 2017 Society of Chemical Industry.