Dietary Zn proteinate with moderate chelation strength alleviates heat stress-induced intestinal barrier function damage by promoting expression of tight junction proteins via the A20/NF-κB p65/MMP-2 pathway in the jejunum of broilers

BACKGROUND

The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength (Zn-Prot M) can alleviate heat stress (HS)-induced intestinal barrier function damage of broilers. A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers. Under high temperature (HT), a 1 (Control, HT-CON) + 2 (Zn source) × 2 (added Zn level) factorial arrangement of treatments was used. The 2 added Zn sources were Zn-Prot M and Zn sulfate (ZnS), and the 2 added Zn levels were 30 and 60 mg/kg. Under normal temperature (NT), a CON group (NT-CON) and pair-fed group (NT-PF) were included.

RESULTS

The results showed that HS significantly reduced mRNA and protein expression levels of claudin-1, occludin, junctional adhesion molecule-A (JAMA), zonula occludens-1 (ZO-1) and zinc finger protein A20 (A20) in the jejunum, and HS also remarkably increased serum fluorescein isothiocyanate dextran (FITC-D), endotoxin and interleukin (IL)-1β contents, serum diamine oxidase (DAO) and matrix metalloproteinase (MMP)-2 activities, nuclear factor kappa-B (NF-κB) p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum. However, dietary supplementation with Zn, especially organic Zn as Zn-Prot M at 60 mg/kg, significantly decreased serum FITC-D, endotoxin and IL-1β contents, serum DAO and MMP-2 activities, NF-κB p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers, and notably promoted mRNA and protein expression levels of claudin-1, ZO-1 and A20.

CONCLUSIONS

Our results suggest that dietary Zn, especially 60 mg Zn/kg as Zn-Prot M, can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.

Basis for the diversity and extent in loss of digestible nutrients created by dietary phytin: Emphasis on fowl and swine

Phytin is the Ca2+-Mg2+-K+ salt of phytic acid that is created and deposited in the aleurone layer and/or germ of grains and legumes. Its high presence in feedstuffs for fowl and swine diets results in it being a universal and significant impediment to optimum performance. Phytin impairs gastrointestinal recovery of a wide array of nutrients, the effect varying with the nutrient concerned. On exposure to low pH during gastric digestion, phytin dissociates into phytic acid and solubilized Ca2+. Even at low gastric pH, phytic acid is negatively charged which forms the basis of its anti-nutritive behavior. Pepsinogen has extensive basic amino acids on its activation peptide that are presented as cations at low pH which are targeted by pepsin for activation. Partially crystalized Ca2+ near the enzyme's active site further stabilizes its newly formed structure. Thus, phytic acid appears to interfere with gastric digestion by several mechanisms; interfering with pepsinogen activation by binding to the polypeptide's basic amino acids; coordinating free Ca2+, destabilizing pepsin; binding some dietary proteins directly, further compromising gastric proteolysis. Upon digesta attaining neutrality in the duodenum, Ca2+ and other cations re-bind with accessible anions, phytic acid being a significant contender. Phytate not only binds free cations but can also strip them from enzymes (e.g. Ca2+, Zn2+) which reduces their structural resistance to autolysis and ability as co-factors (e.g. Zn2+) to increase enzyme activity. Goblet cells initially employ Ca2+ as an electronic shield between mucin layers enabling granule formation and cell storage. After mucin granule release, Ca2+ is progressively displaced by Na+ to free the viscous mucins enabling its translocation. Mucin entangles with the glycocalyx of adjacent enterocytes thereby constructing the unstirred water layer (USWL). Excessive removal of Ca2+ from mucin by phytic acid increases its fluidity facilitating its loss from the USWL with its associated Na+. This partly explains increased mucin and Na+ losses noted with high phytate diets. This review suggests that phytic acid binding of Ca2+ and less so Zn2+ is the basis for the diversity in nutrient losses encountered and that such losses are in proportion to dietary phytate content.

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.

Impact of Maternal and Offspring Dietary Zn Supplementation on Growth Performance and Antioxidant and Immune Function of Offspring Broilers

The current study investigated the effects of the maternal Zn source in conjunction with their offspring’s dietary Zn supplementation on the growth performance, antioxidant status, Zn concentration, and immune function of the offspring. It also explored whether there is an interaction between maternal Zn and their offspring’s dietary Zn. One-day-old Lingnan Yellow-feathered broilers (n = 800) were completely randomized (n = 4) between two maternal dietary supplemental Zn sources [maternal Zn−Gly (oZn) vs. maternal ZnSO4 (iZn)] × two offspring dietary supplemental Zn doses [Zn-unsupplemented control diet (CON), the control diet + 80 mg of Zn/kg of diet as ZnSO4]. oZn increased progeny ADG and decreased offspring mortality across all periods, especially during the late periods (p < 0.05). The offspring diet supplemented with Zn significantly improved ADG and decreased offspring mortality over the whole period compared with the CON group (p < 0.05). There were significant interactions between the maternal Zn source and offspring dietary Zn with regards to progeny mortality during the late phase and across all phases as a whole (p < 0.05). Compared with the iZn group, the oZn treatment significantly increased progeny liver and serum Zn concentrations; antioxidant capacity in the liver, muscle, and serum; and the IgM concentration in serum; while also decreasing progeny serum IL-1 and TNF-α cytokine secretions (p < 0.05). Similar results were observed when the offspring diet was supplemented with Zn compared with the CON group; moreover, adding Zn to the offspring diet alleviated progeny stress by decreasing corticosterone levels in the serum when compared to the CON group (p < 0.05). In conclusion, maternal Zn−Gly supplementation increased progeny performance and decreased progeny mortality and stress by increasing progeny Zn concentration, antioxidant capacity, and immune function compared with the same Zn levels from ZnSO4. Simultaneously, Zn supplementation in the progeny’s diet is necessary for the growth of broilers.

Relative Bioavailability of Trace Minerals in Production Animal Nutrition: A Review

The importance of dietary supplementation of animal feeds with trace minerals is irrefutable, with various forms of both organic and inorganic products commercially available. With advances in research techniques, and data obtained from both in-vitro and in-vivo studies in recent years, differences between inorganic and organic trace minerals have become more apparent. Furthermore, differences between specific organic mineral types can now be identified. Adhering to PRISMA guidelines for systematic reviews, we carried out an extensive literature search on previously published studies detailing performance responses to trace minerals, in addition to their corresponding relative bioavailability values. This review covers four of the main trace minerals included in feed: copper, iron, manganese and zinc, and encompasses the different types of organic and inorganic products commercially available. Their impact from environmental, economic, and nutritional perspectives are discussed, along with the biological availability of various mineral forms in production animals. Species-specific sections cover ruminants, poultry, and swine. Extensive relative bioavailability tables cover values for all trace mineral products commercially available, including those not previously reviewed in earlier studies, thereby providing a comprehensive industry reference guide. Additionally, we examine reasons for variance in reported relative bioavailability values, with an emphasis on accounting for data misinterpretation.

The influence of nutrition on intestinal disease with emphasis on coccidiosis

Ever since the poultry industry began to intensify early last century, coccidiosis has been a significant problem with which it has had to contend. Losses due to mortality and morbidity can be significant and before the advent of control agents there were several practices, some of which were nutritional, which were implemented to limit these losses. The development of coccidiostats reduced these problems considerably and as a result some of the more extreme intervention measures were no longer necessary. Modern day interpretation of what may have been happening with some of these early interventions provide interesting insights into what may be possible today should cocciodiostats be removed. More recent research has also indicated that the diet has a significant influence on the ability of poultry to resist and resolve an infection through direct and indirect effects on the pathogen, the immune system and on the litter. This paper reviews the role of dietary ingredients and nutrients on the pathogen to establish and the host to resist such an infection. There is clearly no panacea, but the combination of a few practices may reduce the overall challenge experienced by the poultry producer.

Broiler responses to copper levels and sources: growth, tissue mineral content, antioxidant status and mRNA expression of genes involved in lipid and protein metabolism

BACKGROUND

Five hundred 8-d old male broilers Cobb500 were randomly allotted into 10 treatments in factorial arrangement with 5 Cu levels (0, 4, 8, 12, and 16 mg/kg), and 2 sources (Cu proteinate, CuPro and Cu sulphate, CuSO4.5H2O) for a 10-d-experiment.

RESULTS

Feed conversion ratio (FCR) was better (P < 0.05) in CuPro fed chicks compared with CuSO4.5H2O group. Average daily feed intake (ADFI) decreased linearly (P < 0.05) as dietary Cu increased. A quadratic response (P < 0.05) to Cu levels was found for FCR, being optimized at 9.87 and 8.84 mg Cu/kg in CuPro and CuSO4.5H2O diets, respectively. Copper supplementation linearly increased liver Cu content (P < 0.05) and tended to linearly increase (P = 0.07) phosphorus (P) and copper in tibia. Manganese and zinc were higher (P < 0.05) in tibia of CuPro fed birds. Broilers fed CuPro exhibited lower liver iron (P < 0.05) content, lower activities of Cu, Zn superoxide dismutase (CuZnSOD) in breast muscle and liver, and glutathione peroxidase in liver. Glutathione peroxidase reduced linearly (P < 0.05) with CuPro levels and increased linearly (P < 0.05) with CuSO4.5H2O levels and were lower (P < 0.05) in all CuPro levels in breast muscle. Breast muscle malondialdehyde concentration tended to be higher (P = 0.08) in broilers fed CuSO4.5H2O. Copper levels linearly increased (P < 0.05) metallothionein (MT) and malate dehydrogenase (MDH) expression in liver, and six-transmembrane epithelial antigen of the prostate-1 (STEAP-1) in the intestine. Copper elicited a quadratic response (P < 0.050) in AKT-1 and mammalian target of rapamycin (mTOR) in breast muscle, CuZnSOD in liver and antioxidant 1 copper chaperone (ATOX 1) in intestine. Broilers fed CuPro exhibited higher mRNA expression of mTOR in muscle breast and lower CuZnSOD in liver and ATOX 1 in intestine. Interaction (P < 0.05) between levels and sources was found in mRNA expression for GSK-3β, MT, and CuZnSOD in breast muscle, FAS and LPL in liver and MT and CTR1 in intestine.

CONCLUSIONS

CuPro showed beneficial effects on feed conversion and bone mineralization. Organic and inorganic Cu requirements are 9.87 and 8.84 mg Cu/kg, respectively.

Genome-Wide Association Study of Phytic Acid in Wheat Grain Unravels Markers for Improving Biofortification

Biofortification of cereal grains offers a lasting solution to combat micronutrient deficiency in developing countries where it poses developmental risks to children. Breeding efforts thus far have been directed toward increasing the grain concentrations of iron (Fe) and zinc (Zn) ions. Phytic acid (PA) chelates these metal ions, reducing their bioavailability in the digestive tract. We present a high-throughput assay for quantification of PA and its application in screening a breeding population. After extraction in 96-well megatiter plates, PA content was determined from the phosphate released after treatment with a commercially available phytase enzyme. In a set of 330 breeding lines of wheat grown in the field over 3 years as part of a HarvestPlus breeding program for high grain Fe and Zn, our assay unraveled variation for PA that ranged from 0.90 to 1.72% with a mean of 1.24%. PA content was not associated with grain yield. High yielding lines were further screened for low molar PA/Fe and PA/Zn ratios for increased metal ion bioavailability, demonstrating the utility of our assay. Genome-wide association study revealed 21 genetic associations, six of which were consistent across years. Five of these associations mapped to chromosomes 1A, 2A, 2D, 5A, and 7D. Additivity over four of these haplotypes accounted for an ∼10% reduction in PA. Our study demonstrates it is possible to scale up assays to directly select for low grain PA in forward breeding programs.

Effects of Zn-Enriched Bifidobacterium longum on the Growth and Reproduction of Rats

Zn is an essential trace element required for maintaining normal growth and development. Zn deficiency can cause growth retardation and reproductive system dysplasia, while Zn supplementation for treating Zn deficiency requires the use of high-quality Zn preparations. In this study, Bifidobacterium longum CCFM1195 was screened for its high Zn enrichment capacity, and the effects of different Zn supplementation regimens and doses on the growth and development of rats after Zn supplementation were investigated by supplementing Zn-deficient rat pups with different doses of various Zn supplements (ZnO, CCFM1195 + ZnO, and Zn-enriched CCFM1195). It was shown that the bioavailability of Zn was positively correlated with indicators of recovery after Zn supplementation, with Zn-enriched CCFM1195 having the best effect, followed by CCFM1195 + ZnO, while ZnO had the worst effect. Significant differences were also observed between the gut microbiota of control, model, and Zn-supplemented rats. Overall, administration of Zn-enriched CCFM1195 was more effective than the other approaches in restoring physical indicators of Zn deficiency after Zn supplementation, and this advantage was more significant at low-dose Zn supplementation.

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.

Effect of L-glutamic acid N,N-diacetic acid on the availability of dietary zinc in broiler chickens

Chelating agents can be used to improve the nutritional availability of trace minerals within the gastrointestinal tract. This study was conducted to determine the effect of a novel chelating agents, L-glutamic acid N,N-diacetic acid (GLDA), a biodegradable alternative to ethylenediaminetetraacetic acid on the nutritional bioavailability of zinc in broilers. Twelve dietary treatments were allocated to 96 pens in a randomized block design. Pens contained 10 Ross 308 male broilers in a factorial design with 6 incremental zinc levels (40, 45, 50, 60, 80, and 120 ppm of total Zn), with and without inclusion of GLDA (0 and 100 ppm) as respective factors. Experimental diets were supplied from day 7 to 21/22 and serum, liver and tibia Zn content were determined in 3 birds per pen. Growth performance and liver characteristics were not affected by dietary treatments, but both supplemental Zn and GLDA enhanced tibia and serum zinc concentration. The positive effect of GLDA was observed at all levels of the dietary Zn addition. The amount of zinc needed to reach 95% of the asymptotic Zn response was determined using nonlinear regression. When GLDA was included in the diet, based on tibia Zn, the same Zn status was achieved with a 19 ppm smaller Zn dose while based on serum Zn this was 27 ppm less Zn. Dietary GLDA reduces supplemental Zn needs to fulfill nutritional demands as defined by tibia Zn and serum Zn response. Considering the positive effect on the nutritional availability of Zn in broilers, GLDA presents an opportunity as biodegradable additive, to reduce Zn supplementation to livestock and thereby reducing Zn excretion into the environment, while fulfilling the nutrition Zn needs of farmed animals.

Effect of manganese source on manganese absorption and expression of related transporters in the small intestine of broilers

An experiment was conducted to investigate the effect of manganese (Mn) source on Mn absorption and expressions of Mn, amino acid, and peptide transporters in the small intestine of broilers. A total of 320 Mn-deficient 15-day-old Arbor Acres male broilers were randomly assigned to 5 treatments with 8 replicates/treatment and 8 chicks/replicate and fed an Mn-unsupplemented control diet or the control diet supplemented with 110 mg Mn/kg from either MnSO4, or 1 of 3 organic Mn chelates with weak (OW), moderate (OM), or strong (OS) chelation strength for 14 D. The plasma Mn contents were higher (P < 0.03) in supplemental Mn groups than in the control group, in OS group than in OM group, and in OM group than in OW and MnSO4 groups on day 28. Broilers fed diets supplemented with Mn had higher (P < 0.02) duodenal divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) mRNA levels and FPN1 protein level on both days 21 and 28 than those fed the control diet. Duodenal DMT1 mRNA and protein levels were higher (P < 0.05) in OM and OS groups than in OW and MnSO4 groups on day 28. The mRNA levels of amino acid transporters [b0, +-type amino acid transporter 1 (B0AT1) and excitatory amino acid transporter 3 (EAAT3)] were higher (P < 0.0005), and peptide transporter 1 was lower (P < 0.04) in the ileum than in the duodenum and jejunum; however, Mn source did not affect (P > 0.05) mRNA levels of amino acid and peptide transporters in the small intestine of broilers. The results from the present study indicate that both DMT1 and FPN1 facilitated Mn absorption, however, the amino acid and peptide transporters might not be involved in the transport of the organic Mn chelates; organic Mn chelates with moderate and strong chelation strength, especially strong chelation strength, showed higher Mn absorption possibly due to enhanced DMT1 expression in the duodenum of broilers.

Cytokine response after stimulation of culture cells by zinc and probiotic strain

Intestinal porcine epithelial cells were used for an in vitro analysis of mRNA expression levels of inflammatory cytokines (IL-8, IL-18) and transcriptional factors (MyD88 and NF-κβ). Cells were exposed to inorganic and organic zinc sources (in two different concentrations-50 μmol/L and 100 μmol/L) alone or combined with Lactobacillus reuteri B6/1, which was also applied individually. The total exposure time was 4 h. Quantitative reverse transcriptase PCR was used to determine expression levels of the aforementioned parameters. In general, upregulation was observed; however, a decrease of some mRNA's abundance was also determined. Differences in expression were analysed statistically using ANOVA and Tukey analyses. High relative expression was shown for IL-8, IL-18 and MyD88 in groups treated with 100 μmol/L of inorganic sources of zinc (ZnSO₄) (p < 0.05), while groups treated with the organic form did not exhibit significant changes in expression. Also, 50 μmol/L of either zinc source did not significantly modify the transcriptional profile of the cytokines and transcription factors, showing that even inorganic sources, at lower concentrations, do not elicit a significant inflammatory reaction. In summary, supplementation of organic zinc source (Gly-Zn chelate) ensures that IL-8, IL-18, MyD88 and NF-κβ expression levels are not positively regulated. In contrast, inorganic sources of zinc (ZnSO₄) could induce an inflammatory reaction. However, this response could be dampened if L. reuteri B6/1 is administered, showing the helpful aspect of using probiotics to modulate an inflammatory response. Conclusively, the use Gly-Zn chelate appears as an optimal alternative for Zn administration that does not compromise normal intestinal homeostasis.

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.

Effects of Dietary Zinc on Carcass Traits, Meat Quality, Antioxidant Status, and Tissue Zinc Accumulation of Pekin Ducks

This study investigated the effects of dietary zinc on carcass traits, meat quality, antioxidant capacity, and tissue zinc accumulation of Pekin ducks. A total of 768 1-day-old Pekin ducks were randomly allocated to six dietary treatments and penned in groups of 16 with 8 pens per treatment. Ducks were fed a basal corn-soybean meal diet supplemented with graded levels of zinc sulfate (0, 15, 30, 60, 120, 240 mg zinc/kg) for 35 days. The slaughter weight, carcass weight, eviscerated weight, and breast and leg muscle weight of Pekin ducks were increased with increasing dietary zinc levels (P < 0.05). Zinc supplementation increased the pH value at 24-h postmortem and the intramuscular fat (IMF) (P < 0.05), but decreased the lightness value, drip loss, and shear force in breast meat of ducks (P < 0.05). Increasing dietary zinc increased the activity of superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), catalase (CAT), and the content of glutathione (GSH), as well as decreased the malondialdehyde (MDA) level in breast muscle (P < 0.05). RT-qPCR analysis demonstrated that supplemental zinc notably enhanced the transcription of SOD, GPX, GR, CAT, and nuclear factor erythroid 2-related factor 2 (Nrf2) (P < 0.05). Meanwhile, zinc accumulation in plasma, breast muscle, liver, and tibia were linearly increased with increasing zinc supplementation (P < 0.05). These results indicated that zinc supplementation could improve carcass traits and meat quality and increase the activities and mRNA levels of antioxidant enzymes in breast muscle of Pekin duck. Base on broken-line regression analysis that 91.32 mg/kg of dietary zinc was suggested for optimal carcass traits, meat quality, antioxidant capacity, and zinc deposition of Pekin duck.

Effects of Phytase Supplementation to Diets with or without Zinc Addition on Growth Performance and Zinc Utilization of White Pekin Ducks

The effect of phytase and inorganic Zn supplementation was studied in 180 male White Pekin ducks (WPD) from 1 to 56 days of age. The birds were divided into four groups fed the same basal diet (containing 26 ppm of Zn from raw materials): the control group did not receive Zn supplementation; the second group was supplemented with 30 ppm of Zn oxide; and the third and fourth groups were fed the control and the 30 ppm diets, respectively, both supplemented with 500 U of E. coli phytase. Each group contained five replicates of nine ducks. The body weight and feed intake were recorded at 1, 28 and 56 days of age. At 56 days of age, five birds/group were used to measure feed digestibility and five other birds/group were slaughtered. Zn at 30 ppm increased the body weight gain (BWG, p < 0.01) and feed intake (p < 0.05) and improved the feed conversion (FCR, p < 0.05) of the growing ducks. The Zn retention and Zn level in the excreta increased (p < 0.01) due to Zn supplementation. The addition of phytase improved BWG (p < 0.01) and FCR (p < 0.05) of growing ducks. The use of phytase reduced (p < 0.01) the level of Zn in duck excreta. Phytase supplementation to the basal diet at 30 ppm seems to be adequate to meet Zn requirements for ducks without further Zn additions.

Effects of sources and concentrations of zinc on growth performance, nutrient digestibility, and fur quality of growing-furring female mink (Mustela vison)

A completely randomized 3 × 3 + 1 factorial experiment was conducted to evaluate the effects of sources and concentrations of Zn on growth performance, nutrient digestibility, serum biochemical endpoints, and fur quality in growing-furring female black mink. One hundred fifty healthy 15-wk-old female mink were randomly allocated to 10 dietary treatments ( = 15/group) for a 60-d trial. Animals in the control group were fed a basal diet, which consisted of mainly corn, soybean oil, meat and bone meal, and fish meal, with no Zn supplementation. Mink in the other 9 treatments were fed the basal diet supplemented with Zn from either zinc sulfate (ZnSO), zinc glycinate (ZnGly), or Zn pectin oligosaccharides (ZnPOS) at concentrations of either 100, 300, or 900 mg Zn/kg DM. The results showed that mink in the ZnPOS groups had higher ADG than those in the ZnSO groups (main effect, < 0.05). The addition of Zn reduced the G:F ( < 0.05). In addition, CP and crude fat digestibility were linearly increased with Zn supplementation ( < 0.05) and N retention tended to increase with Zn addition ( = 0.08). Dietary Zn supplementation increased the concentration of serum albumin and activity of alkaline phosphatase ( < 0.05). There was a linear effect of dietary Zn on the concentration of tibia Zn and pancreatic Zn ( < 0.05). For fur quality characteristics, the fur density and hair color of mink were improved by dietary Zn concentration ( < 0.05). Compared with ZnSO (100%), relative bioavailability values of ZnGly were 115 and 118%, based on tibia and pancreatic Zn, respectively, and relative bioavailability values of ZnPOS were 152 and 142%, respectively. In conclusion, this study demonstrates that Zn supplementation can promote growth and increase nutrient digestibility and fur quality and that ZnPOS is more bioavailable than ZnSO and ZnGly in growing-furring female mink.

Optimization of dietary zinc for egg production and antioxidant capacity in Chinese egg-laying ducks fed a diet based on corn-wheat bran and soybean meal

The aim of this study was to evaluate the effect of zinc supplementation on productive performance and antioxidant status in laying ducks. Five-hundred-four laying ducks were divided into 7 treatments, each containing 6 replicates of 12 ducks. The ducks were caged individually and fed a corn-soybean meal and wheat bran basal diet (37 mg Zn/kg) or the basal diet supplemented with 15, 30, 45, 60, 75, or 90 mg Zn/kg (as zinc sulfate). During the early laying period of 10 d (daily egg production <80%), egg production, daily egg mass, and FCR increased quadratically with increasing dietary Zn levels (P < 0.05). The highest egg production and daily egg weight were obtained when 30 or 45 mg Zn/kg diet was supplemented, with lowest FCR. Similarly, the highest egg production and daily egg mass were observed in the group supplemented with 30 or 45 mg Zn/kg during the peak laying period of the subsequent 120 d (daily egg production >80%). Average egg weight and feed intake did not differ among the groups of graded Zn supplementation.The egg quality was not affected by dietary Zn, including the egg shape index, Haugh unit, yolk color score, egg composition, and shell thickness. The activities of plasma activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) increased in a quadratic manner (P < 0.001) with increasing supplemental Zn. Plasma concentration of Zn increased quadratically (P < 0.05) as dietary Zn increased. The hepatic activity of Cu/Zn-SOD and GSH-PX increased quadratically (P < 0.05) with increasing dietary Zn. Plasma Zn concentrations were positively correlated with activities of T-SOD (P < 0.05), and positively with plasma Cu. Plasma concentration of reduced glutathione was correlated with plasma Cu. In conclusion, supplementation of Zn at 30 or 45 mg/kg to a corn-wheat bran and soybean basal diet may improve the productive performance and enhance the antioxidant capacity.

Effects of Different Sources and Levels of Zinc on Growth Performance, Nutrient Digestibility, and Fur Quality of Growing-Furring Male Mink (Mustela vison)

The objective of this study was to investigate the effects of different sources and levels of zinc (Zn) on growth performance, nutrient digestibility, serum biochemical parameters, and fur quality in growing-furring male mink. Animals in the control group were fed a basal diet with no Zn supplementation. Mink in the other nine treatments were fed the basal diet supplemented with Zn from either grade Zn sulfate (ZnSO₄·7H₂O), Zn glycinate (ZnGly), or Zn pectin oligosaccharides (ZnPOS) at concentrations of either 100, 300, or 900 mg Zn/kg dry matter. One hundred and fifty healthy 15-week-old male mink were randomly allocated to ten dietary treatments (n = 15/group) for a 60-day trial from mid-September to pelting in December. Mink in the Zn-POS groups had higher average daily gain than those in the control group (P < 0.05). Zn source slightly improved the feed/gain (P = 0.097). N retention was increased by Zn addition (P < 0.05). Mink supplemented with dietary Zn had higher (P < 0.05) pancreas Zn level than the control group. Fur length was greater (P < 0.05) in ZnGly and ZnPOS groups compared with the control. In addition, fur length and fur density increased (linear, P < 0.05) with Zn supplementation in the diet. In conclusion, our data show that dietary Zn addition improves growth performance by increasing nitrogen retention and fat digestibility in growing-furring mink and Z-POS is equally bioavailable to mink compared to ZnGly.

Effects of Maternal Zinc Glycine on Mortality, Zinc Concentration, and Antioxidant Status in a Developing Embryo and 1-Day-Old Chick

This study was conducted to investigate the effects of maternal zinc glycine (Zn-Gly) supplementation as an alternative for zinc sulfate (ZnSO₄) on mortality, zinc (Zn) concentration, and antioxidant status in a developing embryo and 1-day-old chick. Six hundred 39-week-old broiler breeders were randomly assigned to 6 treatments, each treatment including 5 replicates with 20 birds each. Six treatments received a basal diet (control, 24 mg Zn/kg diet) or a basal diet supplemented with ZnSO₄ (80 mg Zn/kg) or Zn-Gly (20, 40, 60, or 80 mg Zn/kg), respectively. The experiment lasted for 8 weeks after a 4-week pre-experiment with a basal diet. At the last week, 100 eggs per replicate were randomly collected for incubation. Compared with the control treatment, Zn supplementation decreased (P < 0.05) embryo mortalities of the late stage and the whole period, increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick, and improved (P < 0.05) antioxidant status in the embryo of d19 and 1-day-old chick. Compared with the ZnSO₄ treatment, 80 mg Zn/kg Zn-Gly treatment significantly decreased (P < 0.05) the late stage embryo mortality and increased (P < 0.05) liver Zn concentration in the embryo of d9, d19, and 1-day-old chick. The 80 mg Zn/kg Zn-Gly treatment significantly increased (P < 0.05) copper-zinc superoxide dismutase activity in d19 embryo and 1-day-old chick, total superoxide dismutase activity in 1-day-old chick, and copper-zinc superoxide dismutase messenger RNA (mRNA) abundance of d9 embryo and 1-day-old chick than that in ZnSO₄ treatment. The liver metallothionein concentration of the developing embryo and 1-day-old chick and its mRNA abundance of d19 embryo were also significantly increased (P < 0.05) in the 80 mg Zn/kg Zn-Gly treatment in comparison with ZnSO₄ treatment. In conclusion, maternal Zn supplementation decreased embryo mortalities of the late stage and the whole period by increasing liver Zn concentration and antioxidant status in d19 embryo and 1-day-old chick, and 80 mg Zn/kg from Zn-Gly treatment was the optimum choice.

The Effect of Inorganic or Organic Zinc on the Morphology of the Intestine in Broiler Chickens

This study compared the effect of dietary supplementation with an inorganic or organic zinc source on the gut morphology in the jejunum of broilers. One-day-old chickens were fed a basal diet (Control group: BD — 32 mg Zn.kg−1 DM), or the same BD supplemented with 30 mg or 70 mg of Zn per kg of DM in the form of ZnSO4.H2O (Group 1: 30 mg ZnSO4; Group 2: 70 mg ZnSO4), and 30 mg or 70 mg of Zn per kg of DM in the form of zinc chelate of glycine hydrate (Group 3: 30 mg Zn-Gly; Group 4: 70 mg Zn-Gly) for 40 days. The villus height was increased in the groups which received 30 mg ZnSO4 and 70 mg ZnSO4 and or 70 mg ZnSO4, as compared to the BD and 30 mg Zn-Gly. The villus surface was higher in all groups receiving the Zn supplements in comparison to the BD.

Effect of iron source on iron absorption and gene expression of iron transporters in the ligated duodenal loops of broilers

This experiment was conducted to investigate the effect of iron source on Fe absorption and the gene expression of divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) in the ligated duodenal loops of broilers. The in situ ligated duodenal loops from Fe-deficient broiler chicks (28-d-old) were perfused with Fe solutions containing 0 to 14.33 mmol Fe/L from 1 of the following: Fe sulfate (FeSO∙7HO), Fe methionine with weak chelation strength (Fe-Met W; chelation strength is expressed as quotient of formation [Q] value, Q = 1.37), Fe proteinate with moderate chelation strength (Fe-Prot M; Q = 43.6), and Fe proteinate with extremely strong chelation strength (Fe-Prot ES; Q = 8,590) for up to 30 min. The gene expression of DMT1 and FPN1 in the duodenal loops from the control group and the groups treated with 3.58 mmol Fe/L from 1 of 4 Fe sources was analyzed. The absorption kinetics of Fe from different Fe sources in the duodenum followed a saturated carrier-dependent transport process. The maximum transport rate (J) values in the duodenum were greater ( < 0.03) for Fe-Prot ES and Fe-Prot M than for Fe-Met W and FeSO∙7HO. The Fe perfusion inhibited ( < 0.05) the mRNA expression of but enhanced ( < 0.0008) the mRNA expression of in the duodenum and had no effect ( > 0.14) on the protein expression levels of the 2 transporters. These results indicated that organic Fe sources with greater Q values showed higher Fe absorption; however, all Fe sources followed the same saturated carrier-dependent transport process in the duodenum, and DMT1 and FPN1 might participate in Fe absorption in the duodenum of broilers regardless of Fe source.

Organic zinc absorption by the intestine of broilers in vivo

In Expt 1, a Zn-unsupplemented basal diet (control) and the basal diet supplemented with one of four different Zn sources, including ZnSO4, Zn-amino acid chelate with a weak chelation strength (Zn-AA W), Zn-protein chelate with a moderate chelation strength (Zn-Pro M) and Zn-protein chelate with a strong chelation strength (Zn-Pro S) were fed to broiler chickens from days 14 to 28. On day 28, Zn content in plasma from the hepatic portal vein increased (P0·05) and Zn-AA W(P<0·04) were higher than those for ZnSO4. These findings indicate that organic Zn absorption (especially Zn-Pro S) in intact living broilers was more effective than that of inorganic Zn; organic Zn absorption in the ligated duodenal segment was a saturable carrier-mediated process similar to that of ZnSO4. Moreover, except for MT, there might be other Zn transporters involved in Zn absorption that are affected by different Zn sources.

Kinetics of iron absorption by in situ ligated small intestinal loops of broilers involved in iron transporters

Two experiments were conducted with 28-d-old commercial male broilers to study the kinetics of iron (Fe) absorption and the effect of Fe treatment on divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) mRNA levels in in situ ligated segments from different small intestinal regions of broilers. In Exp. 1, we compared Fe absorption in 3 small intestinal segments at different post-perfusion time points after perfusion with 0.45 m of Fe as Fe sulfate (FeSO ∙ 7HO), and found that the Fe absorption in the duodenum at 30, 45, and 60 min was greater ( < 0.006) than that in the jejunum, and at 60 min, the Fe absorption in the duodenum was greater ( = 0.034) than that in the ileum. In addition, the Fe absorption at 30 min was more than 85.0% of the maximum absorption in each segment. In Exp. 2, a kinetic study of Fe absorption was performed with the duodenal, jejunal, and ileal loops perfused with solutions containing 0 (control), 0.11, 0.22, 0.45, 0.80, 1.79, or 3.58 m of Fe as FeSO 7HO. The Fe concentrations in perfusates were measured at 30 min after perfusion, and in the control group and the group treated with 0.45 m Fe as FeSO 7HO, the DMT1 and FPN1 mRNA levels in the ligated duodenum, jejunum, and ileum were analyzed. The kinetic curves of Fe absorption showed that Fe absorption in the duodenum and jejunum depended on a saturated carrier-mediated process. The maximum absorption rate in the duodenal segment was greater ( < 0.0001) than that in the jejunum (42.75 vs. 8.16 nmol × cm × min), and the Michaelis-Menten constant value was higher ( < 0.0001) in the duodenum than in the jejunum (6.16 vs. 1.31 m). In the ileum, however, the Fe absorption was a non-saturated diffusion process, and the diffusive constant was 3.54 × 10 cm × min. The DMT1 and FPN1 mRNA levels in the duodenum were greater ( < 0.0001) than those in the jejunum and ileum, and greater ( < 0.009) in the jejunum than in the ileum. No differences ( > 0.25) were detected in the DMT1 and FPN1 mRNA levels of the duodenum or jejunum and the DMT1 mRNA level of the ileum between the control and the 0.45 m Fe group, but Fe perfusion increased ( < 0.03) FPN1 mRNA level in the ileum. The above results indicate that the duodenum is the main site of Fe absorption in the small intestine of broilers, and Fe absorption in the duodenum and jejunum is a saturated carrier-mediated process, but a non-saturated diffusion process in the ileum.

Use of Zn concentration in the gastrointestinal tract as a measure of phytate susceptibility to the effect of phytase supplementation in broilers

Zinc (Zn) is the most vulnerable cation to complexation with phytate. An experiment was conducted to evaluate the potential of measurements of Zn concentration in the gastrointestinal tract as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers. Ross 308 broilers (n = 180) were fed one of 5 experimental diets with differing phytase activity levels, analyzed at 605, 1150, 1804, 3954, and 5925 U/kg. Broiler performance and Zn concentration, pH, and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum were analyzed at d 21 post hatch. Phytate susceptibility to phytase degradation was determined in vivo and in vitro by measuring total phytate-P hydrolyzed in the tract or in conditions that mimicked the tract, respectively. Phytase activity level had a significant (P < 0.05) impact on Zn concentration and phytate hydrolyzed in the gizzard and ileum, but not in the duodenum. Strong relationships were observed between the amount of phytate hydrolyzed and Zn concentration in the gizzard in birds fed the diets with 1804 U/kg or higher levels of phytase. Phytate and phytase effects could therefore potentially be evaluated by measuring Zn concentration in the gizzard. Susceptible phytate levels measured in vivo and in vitro were almost identical in the diet with phytase activity of 5925 U/kg, but in the diets with lower phytase activity levels the in vitro assay overestimated the amount of P released. There were strong relationships between in vivo susceptible phytate level and pH and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum and Zn concentration in the gizzard and ileum. This illustrates that phytate susceptibility directly effects mineral availability in the gastrointestinal tract. Measurements of Zn concentration in the gastrointestinal tract, particularly in the gizzard, can potentially be used as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers.

The Potential Impact of Animal Science Research on Global Maternal and Child Nutrition and Health: A Landscape Review

High among the challenges facing mankind as the world population rapidly expands toward 9 billion people by 2050 is the technological development and implementation of sustainable agriculture and food systems to supply abundant and wholesome nutrition. In many low-income societies, women and children are the most vulnerable to food insecurity, and it is unequivocal that quality nutrition during the first 1000 d of life postconception can be transformative in establishing a robust, lifelong developmental trajectory. With the desire to catalyze disruptive advancements in global maternal and child health, this landscape review was commissioned by the Bill & Melinda Gates Foundation to examine the nutritional and managerial practices used within the food-animal agricultural system that may have relevance to the challenges faced by global human health. The landscape was categorized into a framework spanning 1) preconception, 2) gestation and pregnancy, 3) lactation and suckling, and 4) postweaning and toddler phases. Twelve key findings are outlined, wherein research within the discipline of animal sciences stands to inform the global health community and in some cases identifies gaps in knowledge in which further research is merited. Notable among the findings were 1) the quantitative importance of essential fatty acid and amino acid nutrition in reproductive health, 2) the suggested application of the ideal protein concept for improving the amino acid nutrition of mothers and children, 3) the prospect of using dietary phytase to improve the bioavailability of trace minerals in plant and vegetable-based diets, and 4) nutritional interventions to mitigate environmental enteropathy. The desired outcome of this review was to identify potential interventions that may be worthy of consideration. Better appreciation of the close linkage between human health, medicine, and agriculture will identify opportunities that will enable faster and more efficient innovations in global maternal and child health.

Effects of feed supplementation with various zinc sources on mineral concentration and selected antioxidant indices in tissues and plasma of broiler chickens

The aim of this study was to compare the effects of organic dietary zinc (Zn) sources and zinc sulphate on mineral deposition, activity of total superoxide dismutase (SOD) and copper/zinc SOD in tissues of broiler chickens. The performance indicators and lipid peroxidation by measuring the contents of thiobarbituric acid reactive substances (TBARS) in tissues and plasma were also evaluated. Broilers were assigned to 4 treatment groups, each replicated × 6, with 9 birds per replicate. The control group was fed conventional basal diet (BD); the three other groups received identical BD supplemented with 120 mg Zn/kg in the form of zinc sulphate, zinc chelate of glycine hydrate (Zn-Gly), and zinc proteinate (Zn-Pro), respectively. After 5 weeks of dietary treatment, feed supplementation with Zn sulphate resulted in significantly higher average daily weight gain and final body weight, as well as improved feed conversion ratio compared to the Zn-Gly group. Intake of Zn-Pro significantly increased SOD activity (P < 0.05) in erythrocytes and lipid peroxidation (P < 0.01) in plasma. Activities of total SOD and Cu/Zn SOD in liver and kidney were not affected by Zn supplementation. Addition of Zn supplements to broiler diets did not influence concentrations of zinc, manganese and copper in plasma, liver, kidney or breast muscle, with the exception of Zn deposition in the liver being significantly higher (P < 0.05) in the Zn-Pro supplemented group. Results of our study show that organic zinc sources have effects comparable to inorganic zinc sulphate in broilers fed diets containing a higher Zn content.

Effects of supplemental zinc source and level on antioxidant ability and fat metabolism-related enzymes of broilers

The objective of the present study was to investigate the effects of dietary supplemental Zinc (Zn) source and level on antioxidant ability and fat metabolism-related enzymes of broilers. Dietary treatments included the Zn-unsupplemented corn-soybean meal basal diet (control) and basal diets supplemented with 60, 120, or 180 mg Zn/kg as Zn sulfate, Zn amino acid chelate with a weak chelation strength of 6.5 quotient of formation (Q_f) (11.93% Zn) (Zn-AA W), Zn proteinate with a moderate chelation strength of 30.7 Q_f (13.27% Zn) (Zn-Pro M), or Zn proteinate with an extremely strong chelation strength of 944.0 Q_f (18.61% Zn) (Zn-Pro S). The results showed that dietary supplemental Zn increased (P < 0.01) Zn contents in the liver, breast, and thigh muscles of broilers, and up-regulated mRNA expressions of copper and Zn containing superoxide dismutase (CuZnSOD) and metallothioneins (MT) in the liver (P < 0.01) and thigh muscle (P < 0.05), and also enhanced (P < 0.05) CuZnSOD activities in the breast and thigh muscles, which exerted antioxidant ability and a decreased malondialdehyde (MDA) level in the liver (P < 0.01) and breast and thigh muscles (P < 0.05) of broilers. Furthermore, supplemental Zn increased activities of malate dehydrogenase (MDH) and lipoprotein lipase (LPL) in the abdominal fat (P < 0.05), and fatty acid synthetase (FAS) and LPL in the liver (P < 0.01), which were accompanied with up-regulation (P < 0.01) of the mRNA expressions levels of these enzymes in the abdominal fat and liver of broilers. Dietary Zn source, and an interaction between Zn source and level, had no effects on any measurements. It is concluded that dietary Zn supplementation improved Zn status and resulted in promoting antioxidant ability and activities and gene expressions of fat metabolism-related enzymes of broilers regardless of Zn source and level, and the addition of 60 mg Zn/kg to the corn-soybean meal basal diet (a total dietary Zn of approximately 90 mg/kg) was appropriate for improving the above aspects of broilers.

Studies on different iron source absorption by in situ ligated intestinal loops of broilers

The objective of this study was to investigate the iron source absorption in the small intestine of broiler. In situ ligated intestinal loops of 70 birds were poured into one of seven solutions, including inorganic iron (FeSO4, Fe2(SO4)3), organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)), the mixtures (FeSO4 with glycine (Fe+Gly(II)), Fe2(SO4)3 with glycine (Fe+Gly(III)), and no Fe source (control). The total volume of 3-mL solution (containing 1 mg of elemental Fe) was injected into intestinal loops, and then 120-min incubation was performed. Compared with inorganic iron groups, in which higher FeSO4 absorption than Fe2(SO4)3 was observed, supplementation with organic Fe glycine chelate significantly increased the Fe concentration in the duodenum and jejunum (P < 0.05), however, decreased DMT1 and DcytB messenger RNA (mRNA) levels (P < 0.05). Organic Fe glycine chelate (Fe-Gly(II), Fe-Gly(III)) increased serum iron concentration (SI), compared with inorganic 3 valence iron groups (Fe2(SO4)3 and Fe+Gly(III)) (P < 0.05); moreover, lower TIBC value was observed for the chelate (P < 0.05); however, mixture of inorganic iron and glycine did not have a positive role at DMT1 and DcytB mRNA levels, SI and Fe concentrations in the small intestine. Those results indicated that the absorption of organic Fe glycine chelate was more effective than that of inorganic Fe, and the orders of iron absorption in the small intestine were: Fe-Gly(II), Fe-Gly(III) > FeSO4, Fe+Gly(II) > Fe2(SO4)3, Fe+Gly(III). Additionally, the simple mixture of inorganic iron and glycine could not increase Fe absorption, and the duodenum was the main site of Fe absorption in the intestines of broilers and the ileum absorbed iron rarely.

Maternal high-zinc diet attenuates intestinal inflammation by reducing DNA methylation and elevating H3K9 acetylation in the A20 promoter of offspring chicks

A20 is an anti-inflammatory protein that suppresses ubiquitin-dependent nuclear factor κB (NF-κB) signaling, which can be regulated by the microelement zinc (Zn). In mammals, Zn deficiency contributes to a decrease in A20 abundance, which impairs the gut mucosa barrier. However, it is unclear whether the epigenetic reprogramming of the A20 promoter is involved in enhanced Zn-induced intestinal immunity, especially in avian species. Herein, we show that maternal organic Zn exposure resulted in significantly improved intestinal morphological characteristics, increased mucin 2 (MUC2) abundance and secretory IgA (sIgA) production in progeny jejunums. Maternal and offspring Zn supplementation partially alleviated Zn-deficiency-induced inflammatory response, accompanied by repression of NF-κB signaling. Additionally, we observed DNA hypomethylation and histone H3 at lysine 9 (H3K9) hyperacetylation at the A20 promoter region and subsequent activated A20 expression in Zn-supplemented hens compared with control. Notably, maternal dietary organic Zn exposure exhibited greater attenuation of gut impairment, along with increased MUC2 expression and sIgA level, and decreased the abundance of TNF-α and A20 relative to the inorganic-Zn group. Furthermore, enhanced acetylated H3K9 and A20 transcription at day 14 was found in the offspring adequate dietary Zn group. Thus, A20 may be a novel inflammatory-suppressed factor of chick gut that is persistently promoted by dietary Zn supplementation via epigenetic modifications at A20 promoter.

Dietary manganese supplementation influences the expression of transporters involved in iron metabolism in chickens

To investigate the effects of dietary manganese (Mn) supplementation on iron (Fe) metabolism, a total of 480 50-week-old hens were fed the basal diet (control, 24.35 mg Mn/kg) without Mn supplementation for 6 weeks to reduce Mn storage in the body. Hens were then randomly assigned to one of three treatments, which included the control and control added with 60 or 300 mg Mn/kg diet (M-Mn or H-Mn). Duodenum, heart, liver, and tibia were collected in hens after 12-week feeding period. No significant differences were observed in egg production, feed/egg ratio, shell breaking strength, and shell thickness among different treatments. Compared with control or M-Mn, H-Mn decreased (P < 0.05) serum Fe concentration, while increased (P < 0.05) total Fe-binding capacity (TIBC). The Fe concentration decreased (P < 0.05) in duodenum, and tended to reduce (P < 0.10) in liver from control to M-Mn and to H-Mn; whereas, dietary Mn supplementation did not influence (P > 0.10) Fe concentration in the heart and tibia. In conjunction with reduced Fe retention, DMT1 mRNA expression decreased (P < 0.05) with dietary Mn concentration increasing in the duodenum and liver. Duodenal FPN1 mRNA level was higher (P < 0.05) in H-Mn group than that in control or M-Mn group, while hepatic FPN1 mRNA expression was lower (P < 0.05) in M-Mn or H-Mn group when compared with control. The results demonstrated that dietary Mn supplementation decreased Fe concentration in duodenum and liver of hens, which may be related to the alteration of DMT1 and FPN1 expression in these tissues.

Relative bioavailability of iron proteinate for broilers fed a casein-dextrose diet

An experiment was carried out to determine the bioavailability of organic Fe as Fe proteinate (Alltech, Nicholasville, KY) relative to inorganic Fe source (FeSO4•7H2O) for broiler chicks fed a casein-dextrose diet. A total of 448 1-d-old Arbor Acres commercial male broiler chicks were randomly allotted to 1 of 8 replicate cages (8 chicks per cage) for each of 7 treatments in a completely randomized design involving a 2 × 3 factorial arrangement of treatments with 2 Fe sources (Fe proteinate and Fe sulfate) and 3 levels of added Fe (10, 20, or 40 mg of Fe/kg) plus a Fe-unsupplemented control diet containing 4.56 mg of Fe/kg by analysis. Feed and distilled-deionized water were available ad libitum for an experimental phase of 14 d. At 14 d of age, blood samples were collected for testing hemoglobin (Hb) and hematocrit, and calculating total body Hb Fe, whereas liver and kidney samples were excised for Fe analyses. The results showed that ADG, ADFI, blood Hb, hematocrit, and total body Hb Fe and Fe concentrations in liver and kidney increased linearly (P < 0.0001), whereas mortality decreased linearly (P < 0.0001) as dietary Fe level increased. However, only blood Hb concentration and total body Hb Fe differed (P < 0.004) between the 2 Fe sources. Based on slope ratios from the multiple linear regression of Hb concentration and total body Hb Fe on daily intake of analyzed dietary Fe, the bioavailability of Fe proteinate relative to FeSO4•7H2O (100%) was 117 and 114%, respectively (P < 0.009). The results indicated that blood Hb concentration and total body Hb Fe were sensitive indices in reflecting differences in bioavailability among different Fe sources, and Fe proteinate was significantly more available to broilers than inorganic Fe sulfate in enhancing Hb concentration and total body Hb Fe.

Effect of intravenously injected zinc on tissue zinc and metallothionein gene expression of broilers

1. The effect of intravenously injected zinc (Zn) on tissue Zn concentrations and pancreas metallothionein (MT) gene expression in broilers was investigated to detect differences in the tissue utilisation of Zn from different Zn sources. 2. A total of 432 male chickens were randomly allotted on d 22 post-hatch to one of nine treatments in a completely randomised design. Chickens were injected with either a 0.9% (w/v) NaCl solution (control) or a saline solution supplemented with Zn sulphate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M) or strong (Zn-Pro S) chelation strengths at two injected Zn dosages calculated according to two Zn absorbability levels (6 and 12%). 3. Bone and pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations increased on d 6 and 12 after Zn injections as the injected Zn dosages increased. Chickens injected with the Zn-Pro S had lower bone Zn concentration than those injected with the Zn-Pro M or Zn-AA W on d 6 after injections. However, no differences among Zn sources were observed in bone Zn concentration on d 12 after injections, pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations on both d 6 and d 12 after injections. 4. It was concluded that the injected Zn-Pro S was the least favourable for bone Zn utilisation of broilers. The pancreas Zn concentration and pancreas MT gene expressions might not be sensitive enough to detect differences in the tissue utilisation of injected Zn in broilers between organic and inorganic Zn sources or among organic Zn sources.

Effect of zinc source on performance, zinc status, immune response, and rumen fermentation of lactating cows

Two experiments were conducted to examine the effect of zinc (Zn) source on the performance, Zn status, immune response, and rumen fermentation of lactating cows to find the most available Zn source for dairy production. In Experiment 1, a total of 30 multiparous Holstein cows were randomly allocated by body weight and milk yield to one of five treatments in a completely randomized design. Cows were fed a total mixed ration (TMR) with no Zn addition (containing 37.60 mg Zn/kg TMR by analysis), and the basal TMR supplemented with 40 mg Zn/kg TMR from either Zn sulfate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M), or strong (Zn-Pro S) chelation strengths, respectively for 55 days. In Experiment 2, the in vitro rumen fermentation method was used in a completely randomized design involving a 4 × 3 factorial arrangement of treatments. The four Zn sources were the same as those used in Experiment 1, and the three supplemental Zn levels in the rumen fluid were 0, 10, and 20 μg/mL, respectively. The feed intake, milk composition, and somatic cell count (SCC) were unaffected (P > 0.05) by treatments. However, the milk yield was increased (P < 0.05) by addition of Zn from both the Zn-AA W and Zn-Pro S. Plasma Zn level at the end of the experiment was increased (P < 0.05) by addition of Zn from all three organic sources. Serum antibody titers on day 21 after vaccination with foot and mouth disease (FMD) vaccine were increased (P < 0.05) by both supplemental Zn-AA W and Zn-Pro S. The organic Zn sources with different chelation strengths supplemented at the added Zn level of 10 μg/mL were more effective (P < 0.05) in improving the rumen fermentation than Zn sulfate, with the most effective being Zn-AA W. In conclusion, Zn source had no influence on the feed intake, milk composition, and SCC; however, both the Zn-AA W and Zn-Pro S were more effective than Zn-Pro M and Zn sulfate in enhancing the rumen fermentation, Zn status, and humoral immune response as well as improving milk yield of lactating cows. The improved milk production might be attributed to the improved rumen fermentation, Zn status, and immune function.

Dietary manganese modulates expression of the manganese-containing superoxide dismutase gene in chickens

To investigate the possible mechanism(s) by which dietary manganese (Mn) levels and sources modulate the expression of the manganese-containing superoxide dismutase (MnSOD) gene at both the transcriptional and translational levels, we used 432 8-d-old male broiler chicks in a 1 plus 4 × 2 design. Chickens were given either a diet without Mn supplementation [control (C)] or diets supplemented with 100 (optimal) or 200 (high) mg Mn/kg diet from inorganic Mn sulfate (I) or 3 organic complexes of Mn and amino acids with weak (W), moderate (M), or strong (S) chelation strength up to 21 d of age. Compared with C chicks, chicks fed Mn-supplemented diets had higher (P < 0.01) Mn concentrations, specificity protein 1 (Sp1) DNA-binding activities, MnSOD mRNA levels, MnSOD mRNA-binding protein (MnSOD-BP) RNA-binding activities, MnSOD protein concentrations, and MnSOD activities within heart tissue, but lower (P < 0.01) heart activating protein-2 (AP-2) DNA-binding activities. Chicks fed M diets had higher (P < 0.05) heart Mn concentrations, MnSOD mRNA levels, and MnSOD-BP RNA-binding activities compared with those fed the I and W diets and lower (P < 0.01) AP-2 DNA-binding activities than those fed other treatment diets. These results suggest that dietary Mn could modulate the expression of the MnSOD gene in broilers by altering Sp1 and AP-2 DNA-binding activities at the transcriptional level and enhancing MnSOD-BP RNA-binding activity at the translational level. Additionally, an organic Mn source with moderate chelation strength could be more effective than other Mn sources in activating MnSOD gene expression at both the transcriptional and translational levels.