Effect of Zinc Sulfate and Zinc Glycine Chelate on Concentrations of Acute Phase Proteins in Chicken Serum and Liver Tissue

Proteome and Peptidome Changes and Zn Concentration in Chicken after In Ovo Stimulation with a Multi-Strain Probiotic and Zn-Gly Chelate: Preliminary Research

The aim of the study was to determine differences in the proteome and peptidome and zinc concentrations in the serum and tissues of chickens supplemented with a multi-strain probiotic and/or zinc glycine chelate in ovo. A total of 1400 fertilized broiler eggs (Ross × Ross 708) were divided into four groups: a control and experimental groups injected with a multi-strain probiotic, with zinc glycine chelate, and with the multi-strain probiotic and zinc glycine chelate. The proteome and peptidome were analyzed using SDS-PAGE and MALDI-TOF MS, and the zinc concentration was determined by flame atomic absorption spectrometry. We showed that in ovo supplementation with zinc glycine chelate increased the Zn concentration in the serum and yolk sac at 12 h post-hatch. The results of SDS-PAGE and western blot confirmed the presence of Cu/Zn SOD in the liver and in the small and large intestines at 12 h and at 7 days after hatching in all groups. Analysis of the MALDI-TOF MS spectra of chicken tissues showed in all experimental groups the expression of proteins and peptides that regulate immune response, metabolic processes, growth, development, and reproduction.

Zinc glycine chelate ameliorates DSS-induced intestinal barrier dysfunction via attenuating TLR4/NF-κB pathway in meat ducks

BACKGROUND

Zinc glycine chelate (Zn-Gly) has anti-inflammation and growth-promoting properties; however, the mechanism of Zn-Gly contribution to gut barrier function in Cherry Valley ducks during intestinal inflammation is unknown. Three-hundred 1-day-old ducks were divided into 5 groups (6 replicates and 10 ducks per replicate) in a completely randomized design: the control and dextran sulfate sodium (DSS) groups were fed a corn-soybean meal basal diet, and experimental groups received supplements of 70, 120 or 170 mg/kg Zn in form of Zn-Gly. The DSS and treatment groups were given 2 mL of 0.45 g/mL DSS daily during d 15-21, and the control group received normal saline. The experiment lasted 21 d.

RESULTS

Compared with DSS group, 70, 120 and 170 mg/kg Zn significantly increased body weight (BW), villus height and the ratio of villus to crypt, and significantly decreased the crypt depth of jejunum at 21 d. The number of goblet cells in jejunal villi in the Zn-Gly group was significantly increased by periodic acid-Schiff staining. Compared with control, the content of intestinal permeability marker D-lactic acid (D-LA) and fluxes of fluorescein isothiocyanate (FITC-D) in plasma of DSS group significantly increased, and 170 mg/kg Zn supplementation significantly decreased the D-LA content and FITC-D fluxes. Compared with control, contents of plasma, jejunum endotoxin and jejunum pro-inflammatory factors IL-1β, IL-6 and TNF-α were significantly increased in DSS group, and were significantly decreased by 170 mg/kg Zn supplementation. Dietary Zn significantly increased the contents of anti-inflammatory factors IL-10, IL-22 and sIgA and IgG in jejunum. Real-time PCR and Western blot results showed that 170 mg/kg Zn supplementation significantly increased mRNA expression levels of CLDN-1 and expression of OCLN protein in jejunum, and decreased gene and protein expression of CLDN-2 compared with DSS group. The 120 mg/kg Zn significantly promoted the expressions of IL-22 and IgA. Dietary Zn-Gly supplementation significantly decreased pro-inflammatory genes IL-8 and TNF-α expression levels and TNF-α protein expression in jejunum. Additionally, Zn significantly reduced the gene and protein expression of TLR4, MYD88 and NF-κB p65.

CONCLUSIONS

Zn-Gly improved duck BW and alleviated intestinal injury by regulating intestinal morphology, barrier function and gut inflammation-related signal pathways TLR4/MYD88/NF-κB p65.

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.

Effect of Two Particle Sizes of Nano Zinc Oxide on Growth Performance, Immune Function, Digestive Tract Morphology, and Intestinal Microbiota Composition in Broilers

The effects of dietary supplementation with two particle sizes of nano zinc oxide (ZnO) on growth performance, immune function, intestinal morphology, and the gut microbiome were determined in a 42-day broiler chicken feeding experiment. A total of 75 one-day-old Arbor Acres broilers were randomized and divided into three groups with five replicates of five chicks each, including the conventional ZnO group (NC), the nano-ZnO group with an average particle size of 82 nm (ZNPL), and the nano-ZnO group with an average particle size of 21 nm (ZNPS). Each group was supplemented with 40 mg/kg of ZnO or nano-ZnO. Our results revealed that birds in the ZNPS group had a higher average daily gain and a lower feed-to-gain ratio than those in the NC group. ZNPS significantly increased the thymus index and spleen index, as well as the levels of serum metallothionein (MT), superoxide dismutase (SOD), and lysozyme (LZM). The ZNPS treatments reduced interleukin (IL)-1β and tumor necrosis factor-alpha (TNF-α) levels and increased IL-2 and interferon (IFN)-γ levels compared to that in the NC group. Additionally, compared with the birds in the NC group, those in the nano-ZnO group had a higher villus height to crypt depth ratio of the duodenum, jejunum, and ileum. Bacteroides increased in the ZNPS group at the genus level. Further, unidentified_Lachnospiraceae, Blautia, Lachnoclostridium, unidentified_Erysipelotrichaceae, and Intestinimonas were significantly increased in the ZNPL group. In conclusion, nano-ZnO improved the growth performance, promoted the development of immune organs, increased nonspecific immunity, improved the villus height to crypt depth ratio of the small intestine, and enriched the abundance of beneficial bacteria. Notably, the smaller particle size (21 nm) of nano-ZnO exhibited a more potent effect.

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.

Efficacy of hepatoprotectors in prophylaxis of hepatosis of laying hens

Hepatoses of laying hens are quite common in poultry farms as a result of improper practices of poultry maintenance consisting in excessive number of protein feeds for provision of high productivity. The objective of the study was preventive efficacy of Gep-A-Stress hepatoprotectors (carnitine hydrochloride, D L methionine, sorbitol, choline chloride, magnesium sulfate heptahydrate) and Hepasan VS (L-carnitine hydrochloride, sorbitol, choline chloride, magnesium sulfate hepahydrate, betaine hydrochloride, L-arginin) against hepatosis of laying hens. To determine the efficacy of Hep-A-Stres and Hepasan-VS hepatoprotectors during production tests (n = 4,500), we monitored the parameters of survival rate (the final number of individuals as percentage of the initial number) and egg productivity of laying hens. We determined that after 30 days of using the hepatoprotectors, the content of overall protein in blood serum of laying hens of the first and the second experimental groups decreased by 21.4% and 18.9% compared with the parameters prior to providing the hepatoprotectors and by 26.3% and 23.3% compared with the control group after receiving the drug. The urea contents in blood serum increased by 19.0% and 10.5%. Compared with the control, the activity of alanine aminotransferase decreased by 43.7% and 24.1% in the first experimental group and by 23.4% and 14.9% in the second. The activity of aspartate aminotransferase in blood serum of the experimental groups decreased by 10.7%. The cholesterol concentration decreased by 50% and 58.3%. The content of triaglycerols decreased by 24.1% and 8.9% respectively. The concentrations of high-density lipoproteins after 30 days of the experiment decreased by 33.3% and 77.8% respectively, the content of low-density lipoproteins decreased by 61.3% and 40.4% and 42.3%. Population maintenance equaled respectively 97.1%, 98.3% and 98.1%. At the end of the experiment, the egg productivity of laying hens of the first and second groups increased by 4% and 3.6% compared with the control. Therefore, intake of the hepaprotectors by laying hens stimulated their metabolism, positively influenced the blood parameters, survival and egg productivity. The conducted studies confirm the benefits of using hepatoprotectors for the prohylaxis of hepatosis of hens.

Effect of Supplementation of Zinc-Methionine on Egg Production, Semen Quality, Reproductive Hormones, and Hatchability in Broiler Breeders

A biological study was conducted to explore the effect of zinc-methionine (Zn-Met) supplementation on productive, reproductive, and immunological response in broiler breeders. Adult healthy 45-week breeder males (192) and females (288) were used in a completely randomized design. Birds were randomly divided into four treatments consisting of six replicates and fed basal diet (control, 40 mg/kg), basal diet supplemented with Zn-Met 20 (T1), 40 (T2), and 60 mg/kg (T3). There was no effect (P > 0.05) on body weight and feed consumption among the breeders due to the supplementation of organic Zn. The T3 group had significantly (P < 0.05) higher semen volume, sperm motility, concentration, and live sperm count. The seminal plasma calcium and alkaline phosphatase activity were higher (P < 0.05), and total cholesterol and aspartate transaminase levels were low in the T3 group. Birds fed with additional supplementation of Zn (60 mg/kg) had improved both cellular and humoral immunity. Throughout the experimental period, the hen day egg production was comparable (P > 0.05) among the experimental groups. Organic Zn-supplemented group showed significant difference in both the internal and external egg qualities-albumen, yolk index, and shell thickness. The higher dose of organic Zn-fed groups had a significant difference in estrogen and progesterone concentration, and the highest testosterone concentration was observed in the T2 group. Supplementary organic Zn had a significant effect on the concentration of Zn and Cu in the seminal plasma. Serum Zn and Cu concentration was significantly increased due to the supplementation of organic zinc in both male and female breeders. The fertility and hatchability percentage were higher (P < 0.05) in the T2 group. It could be concluded that the additional supplementation of organic Zn (zinc-methionine) at 40 mg/kg to the basal diet improved the reproductive performance in broiler breeders.

Effects of Bacillus subtilis, butyrate, mannan-oligosaccharide, and naked oat (ß-glucans) on growth performance, serum parameters, and gut health of broiler chickens

Four nonantibiotic alternative growth promoters for broiler chickens were evaluated. Ross 308 chicks were fed a control diet (mainly corn and soybean meal) or a diet supplemented with a probiotic (Bacillus subtilis Gallipro DSM 17299), encapsulated butyric acid (Novyrate C), mannan-oligosaccharide (Actigen MOS) or formulated with 20% naked oat (starter diet) and 30% naked oat (grower and finisher). The study was carried out as a complete random blocked design with 10 pens for each diet, 45 birds per pen. Compared to the control, the naked oat diet improved the average daily gain by 16% during the starter phase (up to d 10). The probiotic did so during the grower phase as did butyric acid in the finisher phase (up to d 34). For the experiment overall, the probiotic decreased average daily gain slightly. The best improvement in feed conversion ratio was obtained in the butyrate group (5%). No significant treatment effect on crop pH or on mortality was observed. The naked oat diet gave a slightly lower cecum pH on d 34. The MOS supplement decreased jejunal mass on d 34 and increased villus length (34%) and villus height/crypt depth ratio (32%) measured on d 10. Naked oat, butyric acid and MOS diets all reduced serum endotoxin levels. The probiotic increased serum C-reactive protein. All noncontrol diets reduced serum malondialdehyde. The naked oat diet reduced d 34 litter pH by about 0.3. Some effects of the proposed non-antibiotic growth promoters have been observed and could contribute to livestock performance. Their exact modes of action remained to be defined.

Associations Between Serum Zinc Levels and Alanine Aminotransferase Elevation in Adults

Recent findings showed that zinc might be linked to alanine aminotransferase (ALT) elevation. This analysis aimed to explore the association between serum zinc levels and ALT elevation in adults. Data on serum zinc and ALT levels from adults aged 20 years and older who participated in the 2011-2016 National Health and Nutrition Examination Surveys were analyzed (N = 4138). Individuals with excessive alcohol consumption and hepatitis B or C infection were excluded. ALT elevation was defined as any value above normal of ALT (> 33 IU/L for males and > 25 IU/L for females). The multivariate logistic model and restricted cubic splines were adopted to assess the non-linear relationship. In a fully adjusted model, the odds ratio and 95% confidence interval of ALT elevation for quartile 4 (Q4) vs. quartile 1 (Q1) of serum zinc levels were 1.68 and 1.29-2.20 (per quartile: 1.20 (1.10-1.31)). In subgroup analysis, the association between serum zinc levels and ALT elevation was found in females (Q4 vs Q1: 1.95 (1.20-3.15)), obese individuals (Q4 vs Q1: 1.80 (1.19-2.74)), and young adults (Q4 vs Q1: 1.72 (1.09-2.72)), while the association was not evident in males, non-obese individuals, and adults older than 50 years old. A linear dose-response relationship between serum zinc levels and ALT elevation was found (P_{for non-linearity} = 0.77). In conclusion, serum zinc was positively associated with ALT elevation in adults, and the association was mainly observed in females, obese individuals, and young adults.

Effects of different concentration of organic and inorganic trace minerals (zinc, selenium, and chromium) supplementation on expression of chTLR4 gene and humoral immune response in broilers

BACKGROUND AND AIM

Poultry production is the fastest-growing livestock sector in developing countries. In the poultry diet, trace minerals (zinc [Zn], selenium [Se], and chromium [Cr]) are normally administered in the inorganic form which has been traditionally considered as the most cost-effective and easily available but organic forms of these trace minerals have a higher bioavailability, lower dietary inclusion and cause less environmental pollution as compared to inorganic form. This study aimed to investigate the effect of different concentrations of organic and inorganic forms of trace minerals (Zn, Se, and Cr) supplementation (0-35 days) on expression of chTLR4gene and humoral immune response in broilers.

MATERIALS AND METHODS

A total of 216 broilers were randomly divided into 12 groups and each group divided into three replicates consisting of six broilers each. T1 (R1, R2, and R3) group was kept as control. T2, T3, and T4 (R1, R2, and R3) groups were supplemented with inorganic form of Zn at 40 mg/kg of feed, organic form of Zn at 40 mg/kg of feed, and 50% organic form of Zn at 20 mg/kg of feed, respectively. T5, T6, and T7 (R1, R2, and R3) groups were supplemented with inorganic form of Se at 0.3 mg/kg of feed, organic form of Se at 0.3 mg/kg of feed, and 50% organic form of Se at 0.15 mg/kg of feed, respectively. T8, T9, and T10 (R1, R2, and R3) groups were supplemented with inorganic form of Cr at 2 mg/kg of feed, organic form of Cr at 2 mg/kg of feed, and 50% organic form of Cr at 1 mg/kg of feed, respectively. T11 and T12 (R1, R2, and R3) groups were supplemented with a combination of all three minerals from inorganic and organic forms, respectively.

RESULTS

Reverse transcriptase-polymerase chain reaction gene expression analysis revealed that in bursa of Fabricius, maximum upregulation of chTLR4 (3.0214 fold) was observed in T6 group, and in spleen, maximum upregulation of chTLR4 (3.2140 fold) was observed in T3 group as compared to control group. On day 35, the maximum plasma immunoglobulin G concentration was observed in organic trace minerals (OTMs) supplemented, whereas the minimum concentration was recorded in control group. On day 28 and 35, the overall mean heterophil:lymphocyte ratio showed a significant difference (p<0.05) between control and OTM supplemented groups. A significantly higher immune organ weight (spleen and bursa of Fabricius) was recorded in OTM supplemented group as compared to control and other supplemented group.

CONCLUSION

Supplementation of organic form of Zn, Se, and Cr either alone or in combination increase humoral immune response and upregulation of chTLR4 gene expression in bursa and spleen indicates a beneficial effect of OTM in augmentation of immune system in broilers.

Zinc in Dog Nutrition, Health and Disease: A Review

Simple Summary

This work compiles the current state of knowledge regarding zinc requirements of healthy dogs and biomarkers of zinc status. To ensure an adequate zinc status, it is important to know the zinc content of foods and their bioavailability to assess the need and the ideal supplementation strategy regarding levels and sources of additives in complete dog foods. As zinc is required for enzymatic, structural, and regulatory functions in the animal body, its nutritional status has been associated with several pathologies that may be due to, or exacerbated by, a deficit of dietary zinc supply.

Abstract

Zinc is an essential trace element, required for enzymatic, structural, and regulatory functions. As body reserves are scarce, an adequate zinc status relies on proper dietary supply and efficient homeostasis. Several biomarkers have been proposed that enable the detection of poor zinc status, but more sensitive and specific ones are needed to detect marginal deficiencies. The zinc content of commercial dry dog foods has great variability, with a more frequent non-compliance with the maximum authorized limit than with the nutritional requirement. The bioavailability of dietary zinc also plays a crucial role in ensuring an adequate zinc status. Despite controversial results, organic zinc sources have been considered more bioavailable than inorganic sources, albeit the zinc source effect is more evident after a restriction period of dietary zinc. Many disorders have been associated with inadequate zinc status, not being clear whether the occurrence of the disease is the consequence or the cause. This review presents data on zinc requirements and biomarkers for zinc status, that can be applied for the development of supplementation strategies of zinc in complete pet foods. Moreover, it provides an understanding of the role zinc plays in the health of dogs, and how altered zinc status affects diseases in dogs.

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

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

The Hepatoprotective Effects of Zinc Glycine on Liver Injury in Meat Duck Through Alleviating Hepatic Lipid Deposition and Inflammation

Dietary zinc status was recently approved to exert a powerful influence on liver health, and zinc deficiency results in hepatic injury caused by fat deposition, inflammation, and oxidant stress, but the effect of zinc on hepatic lipid metabolism and liver injury in meat duck has not been well defined. To determine the hepatoprotective effects of graded zinc glycine in meat ducks. A total of 384 1-day-old male meat ducks were subjected to 5 weeks feeding program with three experimental diets: (1) low-zinc diet, (2) adequate-zinc diet, and (3) high-zinc diet. Blood and liver samples were collected for biochemical analysis, gene expression analysis, and histopathological study. Diet with low zinc increased hepatic lipid content and triglyceride concentration. Meat ducks fed low-zinc diet exhibited considerably increased serum alanine aminotransferase (ALT) activity than birds fed other diets among all groups (P < 0.05). Low zinc administration also notably induced hepatocyte apoptosis and stimulated hepatic inflammatory gene expression. Adequate or high zinc supplementation increased hepatic zinc level, reduced hepatic lipid deposition and hepatosomatic indices through suppressing the expression of lipogenic genes including fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) (P < 0.05), and upregulated the mRNA expression of both fatty acid secretion and β-oxidation, including carnitine palmitoyltransferase 1a (Cpt1a), peroxisome proliferator-activated receptor (PPAR)α, and apolipoprotein B (ApoB) (P < 0.05). Dietary zinc addition also declined hepatic mRNA expression of interleukin (IL)-1β and IL-6 (P < 0.05). Furthermore, diets with adequate or high zinc significantly decreased serum ALT activity and hepatocyte apoptosis. These data revealed that supplementing adequate- or high-zinc glycine efficiently protects liver injury by attenuating lipid deposition and hepatic inflammation.

Effect of Zinc Source and Exogenous Enzymes Supplementation on Zinc Status in Dogs Fed High Phytate Diets

Zinc is an essential element, a cofactor of many enzymes, and performs catalytic, structural and regulatory functions. Once in the gastrointestinal tract, zinc can interact with food constituents. Phytic acid, the major phosphorus storage in plants, limits zinc availability from animal feeds due to the formation of insoluble complexes with phytates. This study tested the effect of supplemental zinc source (zinc sulfate and a chelate zinc proteinate) and the addition of exogenous enzymes from a solid-state fermentation product of Aspergillus niger to a high phytate diet. The study was designed according to three Latin Squares 4 × 4 with a 2 × 2 factorial arrangement of treatments, with four periods, four diets, and 12 young adult Beagles. Periods lasted 5 weeks each. Diets were supplemented with 75 mg/kg of zinc sulfate (IZ) or zinc proteinate (OZ), and without or with 200 mg/kg of exogenous enzymes (IZ+, OZ+). Results showed that zinc proteinate increased the bioavailability of phosphorus, yet the zinc biomarkers remained unaffected by the zinc source, with the exception of lymphocyte subsets that benefit from zinc proteinate. The use of exogenous enzymes did not affect zinc availability nor nutrient and energy digestibility.

Effects of dietary zinc source on the metabolic and immunological response to lipopolysaccharide in lactating Holstein dairy cows

The objectives of this study were to evaluate the effects of replacing 40 mg/kg of Zn from Zn sulfate (control; CON) with Zn AA complex (AvZn) on metabolism and immunological responses following an intravenous lipopolysaccharide (LPS) challenge in lactating cows. Cows were randomly assigned to 1 of 4 treatments: (1) pair-fed (PF) control (PF-CON; 5 mL of saline; n = 5), (2) PF AvZn (PF-AvZn; 5 mL of saline; n = 5), (3) LPS euglycemic clamp control (LPS-CON; 0.375 μg of LPS/kg of BW; n = 5), and (4) LPS euglycemic clamp AvZn (LPS-AvZn; 0.375 μg of LPS/kg of BW; n = 5). Cows were enrolled in 3 experimental periods (P). During period 1 (3 d), cows received their respective dietary treatments and baseline data were obtained. During period 2 (P2; 2 d), a 12-h LPS euglycemic clamp was conducted or cows were PF to their respective dietary counterparts. During period 3 (P3; 3 d), cows received their dietary treatment and consumed feed ad libitum. Mild hyperthermia (1°C) was observed in LPS cows at 3 h postbolus. Throughout P2, the rectal temperature of LPS-AvZn cows was decreased (0.3°C) relative to LPS-CON cows. Administrating LPS decreased dry matter intake (47%) during P2, and by experimental design the pattern was similar in PF cohorts. During P3, dry matter intake from LPS cows remained decreased (15%) relative to PF cows. Milk yield from LPS cows decreased (54%) during P2 relative to PF cows, but it was similar during P3. During P2, somatic cell count increased 3-fold in LPS cows relative to PF controls. Dietary AvZn tended to decrease somatic cell count (70%) during P3 relative to LPS-CON cows. Insulin increased 7-fold in LPS cows at 12 h postbolus and remained increased (4-fold) for the duration of P2. Circulating glucagon from LPS cows increased (65%) during P2, and supplementing AvZn blunted the increase (30% relative to LPS-CON). During P2, circulating cortisol increased 7-fold post-LPS infusion relative to PF cows, and supplementing AvZn decreased cortisol (58%) from 6 to 48 h postbolus relative to LPS-CON cows. Administrating LPS increased circulating LPS-binding protein and serum amyloid A (3- and 9-fold, respectively) relative to PF cows. Compared with LPS-CON, LPS-AvZn cows had increased circulating serum amyloid A (38%) 24 h postbolus. The 12-h total glucose deficit was 36 and 1,606 g for the PF and LPS treatments, respectively, but was not influenced by Zn source. In summary, replacing a portion of the Zn sulfate with Zn AA complex appeared to reduce the inflammatory response but had no effect on the glucose deficit.