Comparison the Zn-Threonine, Zn-Methionine, and Zn Oxide on Performance, Egg Quality, Zn Bioavailability, and Zn Content in Egg and Excreta of Laying Hens

A Critical Perspective on Statistical Issues in Estimating Nutrient Bioavailability in Animal Bioassays

Assessing nutrients' relative bioavailability value (RBV) in poultry nutrition has been a prominent subject in the scientific literature for several decades. This method of nutritional evaluation is commonly used to appraise emerging sources of trace minerals and amino acid chelates. References outlining the method for estimating RBV have been available since the 1970s. However, a simplified approach to RBV estimation using the slope-ratio method without preceding statistical considerations to ensure validity and meet fundamental requirements may yield misleading conclusions. Using the slope-ratio method, which involves dividing the regression slope of the test ingredient by that of the reference, can cause uncertainties regarding statistical significance if the model's probability is reported without confidence intervals (CIs) for the RBV estimates. Despite longstanding criticism regarding the misinterpretation and improper use of statistical tests and CIs, these issues persist in estimating RBV using the slope-ratio method. An additional concern is that the misuse of the slope-ratio method and the application of inappropriate statistical analyses can lead to the underestimation of the RBV of nutrients in poultry species. This means that improper application of these methods can cause inaccurately low RBV values, affecting the assessment of nutrient effectiveness. This review addresses the potential pitfalls in peer-reviewed articles within this field, with a particular focus on zinc bioavailability through a reevaluation of RBV data in broilers, laying hens, and honeybees.

Comparison of different dietary levels of iron and zinc for the enrichment of eggs in laying hens

Zinc (Zn) and iron (Fe) are necessary for structural and metabolic functions of the body like, immune competence, physical growth, reproductive function, and neurobehavioral development. The deficiency of micronutrients is a severe public health distress in nearly all developing countries which leads to the syndrome of malnutrition mostly in children and women. The present study was conducted to compare the effect of different levels of Fe and Zn on feed intake (FI), feed conversion ratio (FCR), daily egg production, and Fe and Zn depositions in the egg yolk of laying hens. For this purpose, 80 commercial laying birds were allocated into four groups consisting of four replicates each (n = 5). The basal ration was provided to the control group (C) while three different levels (100, 200, and 300 mg/kg diet/element) of Fe and Zn (1:1) were provided to the FZ100, FZ200, and FZ300 groups, respectively. Overall FI, hen day egg production, and FCR were not affected (p > 0.05). The Fe and Zn content in egg yolk were significantly increased in the FZ300 group after 4 weeks of supplementation. The cost per egg produced in response to different levels of Fe and Zn supplementation was not affected however a numerical increase in cost/egg was found in the FZ300 group. In conclusion, Fe and Zn supplementation (300 mg/kg diet/element) significantly enhanced the egg Fe and Zn contents without adversely affecting production parameters including FI, egg production, and FCR of laying hens.

Evaluating the effect of optimal zinc amino-acid complex supplementation in laying pullets on performance and zinc retention

This study investigated the optimal dietary intake of zinc amino acid complex (Zn-AAC) for white-layer pullets, focusing on their productive performance, biochemical profile, organ biometry, and body zinc retention. The study involved 360 Dekalb White pullets (average weight: 433 ± 4.42 g) aged from 6 to 16 weeks and distributed into 6 treatments with 6 replications each. The Zn-AAC inclusion levels ranged from 5 to 75 mg kg-1. Zinc intake was modeled using a nonlinear equation, Y = ∝ *1- e-βX, where α is the maximum response, β is the rate at which the response approaches the maximum (P < 0.05). The Zn-AAC supplementation had significant effects on average daily gain (ADG), average daily feed intake (ADFI), and feed convention ratio (FCR) (P < 0.01). Optimal intake levels of Zn-AAC were estimated at 0.234, 0.340, and 0.315 mg bird-1 day-1 (5.42, 7.87, and 7.30 mg kg-1) for ADG, ADFI, and FCR, respectively. The Zn-AAC supplementation affected the Zn body retention in pullets (P < 0.01), with an optimal ingestion at 1.86 mg bird -1 day-1, corresponding to a dietary supplementation of 43.10 mg kg-1. Additionally, supplementation affected alkaline phosphatase (ALP) activity (P < 0.01) without significant changes in aspartate aminotransferase, albumin, and globulin levels. The optimal Zn-AAC intake level for ALP activity was 1.45 mg bird -1 day-1, corresponding to dietary supplementation of 33.60 mg kg-1. Based on Zn body retention, we recommend up to 1.86 mg bird -1 day-1 of Zn-AAC, which is equivalent to 43.10 mg kg-1.

Determining the optimal level and the effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period

BACKGROUND

Trace elements, such as zinc, magnesium and copper, are essential for improving the performance and health of broiler breeders and the development of chicken embryos. These elements are integral to various proteins involved in metabolism, hormone secretion and the immune system, necessitating their inclusion in small amounts in poultry diets.

OBJECTIVES

This study aimed to determine the optimal level and effect of different zinc sources on performance, egg quality and the immune system of laying hens at the end of the production period.

METHODS

The experiment involved 520 Lohmann LSL laying hens, aged 80 weeks, divided into 13 treatments with 5 replications and 8 birds per replication. The hens were fed diets supplemented with 40, 60 and 80 mg/kg of zinc from various sources: mineral zinc oxide, mineral zinc sulphate, organic zinc chelated with glycine and organic zinc chelated with an organic acid. Key parameters measured included body weight, egg weight and immune response.

RESULTS

The basal diet contained 63.58 mg/kg of zinc, with the requirement per the Lohmann LSL guideline being 80 mg/kg. Zinc supplementation significantly increased body weight in the second month, with 80 mg/kg being the optimal dose. Zinc oxide notably increased egg weight compared to the control. The hens utilized zinc from all sources, resulting in weight gain and improved parameters such as egg quality. Immune parameters were also positively influenced by zinc supplementation.

CONCLUSIONS

Zinc supplementation at appropriate levels enhances the performance and egg quality of laying hens, particularly at the end of the production period. It improves bioavailability, enriches eggs and mitigates age-related declines in productivity.

Comparative effects of dietary zinc nanoparticle and conventional zinc supplementation on broiler chickens: A meta-analysis

Background and Aim

Zinc (Zn) is important for various physiological processes in broiler chickens, including protein and carbohydrate metabolism, growth, and reproduction. The gastrointestinal absorption of Zn in broiler chickens was notably low. One approach that has been explored for enhancing the bioavailability of Zn is the development of Zn nanoparticles (NPs). Zn is required for various physiological processes in broiler chickens, including protein and carbohydrate metabolism, growth, and reproduction. Therefore, this study aimed to assess the impact of conventional Zn and Zn NPs on broiler chickens using a meta-analysis methodology.

Materials and Methods

A database was built from published literature to evaluate the effects of the addition of Zn NPs and conventional Zn on broiler chicken responses, including the following parameters: production performance; carcass cuts; visceral organ weight; lymphoid organ weight; nutrient digestibility; intestinal villi; mineral Zn, calcium, and phosphorus concentrations; hematology; blood parameters; immunoglobulin; and intestinal bacterial population. Various scientific platforms, including Scopus, Web of Science, PubMed Central, and Google Scholar, were used to search for peer-reviewed articles. A database was created from 25 studies that met the inclusion criteria. The data were then processed for a meta-analysis using a mixed-model methodology. Different types of Zn (NPs versus conventional) were considered fixed effects, different studies were treated as random effects, and p-values were used as model statistics.

Results

Across the parameters observed in this study, the use of Zn NPs was more efficient in Zn utilization than conventional Zn, as evidenced by the average dose of Zn NPs being much lower than that of conventional Zn (79.44 vs. 242.76 mg/kg) yet providing similar (p > 0.05) or even significantly better effects (p < 0.05) compared to conventional Zn usage.

Conclusion

This investigation revealed the beneficial influence of Zn NPs in broiler chickens compared to the conventional utilization of Zn through an all-encompassing meta-analysis. Moreover, Zn NPs have proven to be more effective in Zn utilization when juxtaposed with conventional Zn, as demonstrated by the significantly lower quantity of Zn NPs administered compared to conventional Zn, while yielding comparable or even superior outcomes compared to the traditional utilization of Zn. A limitation of this study is that the Zn NPs used were sourced from inorganic Zn NPs. Therefore, future research should focus on evaluating the efficiency of organic Zn NPs in broiler chicken feed.

Effects of Dietary Valine Chelated Zinc Supplementation on Growth Performance, Antioxidant Capacity, Immunity, and Intestine Health in Weaned Piglets

This study was conducted to investigate the effects of dietary valine chelated zinc (ZnVal) supplementation on growth performance, antioxidant capacity, immunity, and intestine health in weaned piglets. A total of 240 healthy 35-day-old weaned piglets (Duroc × Landrace × Yorkshire, average weight 10.70 ± 0.14 kg) were randomly divided into five groups with six replicate pens and eight piglets per pen. Dietary treatments were a corn-soybean meal basal diet supplemented with 0, 25, 50, 75, and 100 mg/kg ZnVal, respectively. The experiment lasted for 28 days. Results showed that average daily gain (ADG) was increased (P < 0.05) by ZnVal with 75-100 mg/kg supplementation on days 15-28 and with 50-100 mg/kg supplementation on days 1-28. Supplementation of 25-100 mg/kg ZnVal reduced (P < 0.01) the diarrhea rate of weaned piglets on days 1 to 14 and 1 to 28. Dietary supplementation with 25-100 mg/kg ZnVal increased (P < 0.05) copper/zinc-superoxide dismutase (Cu/Zn-SOD) and decreased malonaldehyde (MDA) activities in the serum on day 14 and 28. Supplementation of 25-100 mg/kg ZnVal increased (P < 0.05) glutathione peroxidase (GSH-Px) activity in serum on day 14. Additionally, the supplementation of 75 mg/kg ZnVal significantly increased the activity of superoxide dismutase (SOD) and Cu/Zn-SOD in the liver (P < 0.05). Furthermore, the supplementation of 25-100 mg/kg ZnVal significantly increased the total antioxidant capacity (T-AOC) in the liver (P < 0.05). Higher (P < 0.05) concentrations of IgG in the serum were measured from piglets supplemented with 75-100 mg/kg ZnVal on day 14 and dietary supplementation with 25-100 mg/kg ZnVal increased the level of immunoglobulin G (IgG) in serum on day 28 (P < 0.05). In addition, higher (P < 0.05) concentrations of immunoglobulin A (IgA) in the duodenum and ileum were measured from piglets supplemented with 75 mg/kg ZnVal and the supplementation of 25-100 mg/kg ZnVal also showed a higher (P < 0.05) concentration of immunoglobulin G (IgG) in duodenum. Supplementation of 50-100 mg/kg ZnVal increased the villus height and villus height/crypt depth of jejunum (P < 0.05). Moreover, dietary supplementation with 75-100 mg/kg ZnVal showed a higher (P < 0.05) concentration of zinc in the liver and supplementation of 50-100 mg/kg ZnVal increased (P < 0.05) the concentration of zinc in the heart, spleen, and kidney. In conclusion, the present research showed that supplementation of ZnVal improves growth performance by increasing antioxidant capacity and immunity and regulating intestinal morphology and the optimal inclusion level of ZnVal was 65~80 mg/kg.

Organic or Inorganic Zinc for Laying Hens? A Systematic Review and Meta-analysis of the Effects of Zinc Sources on Laying Performance, Egg Quality, and Zinc Excretion

The higher availability of zinc (Zn) from organic than inorganic sources is already established, but more assertive and cost-friendly protocols on the total replacement of inorganic with organic Zn sources for laying hens still need to be developed. Because some discrepancy in the effects of this replacement in laying hen diets is noticeable in the literature, the objective of this meta-analysis was to properly quantify the effect size of total replacing inorganic Zn with organic Zn in the diet of laying hens on their laying performance, egg quality, and Zn excretion. A total of 2340 results were retrieved from Pubmed, Scielo, Scopus, WOS, and Science Direct databases. Of these, 18 primary studies met all the eligibility criteria and were included in this meta-analysis. Overall, the replacement of inorganic Zn with organic Zn, regardless of other factors, improved (p < 0.01) egg production by 1.46%, eggshell thickness by 0.01 mm, and eggshell resistance by 0.11 kgf/cm2. Positive results of the same nutritional strategy on egg weight and Zn excretion were only observed at specific conditions, especially when organic Zn was supplemented alone in the feed, not combined with other organic minerals. Therefore, there is evidence in the literature that the total replacement of inorganic Zn with organic Zn improves egg production, eggshell thickness, and eggshell resistance. Factors such as hen age and genetics, organic Zn source, concentration of Zn in the feed, and the strategy of its supplementation have to be more carefully considered in protocols designed to address egg weight and Zn excretion by the hen.

Comparative effects of zinc hydroxy chloride, zinc sulfate, and zinc-methionine on egg quality and quantity traits in laying hens

The aim of this experiment was to evaluate the effect of different levels of zinc supplements on egg quality and quantity traits as well as egg enrichment with zinc in laying hens from 40 to 50 weeks of age. A total of 240 Hy-line laying hens were distributed among eight treatments and five replications (six birds per replication). The control group received no zinc diet, while the other treatments were supplemented with varying levels of zinc sulfate (80, 120, and 160 mg/kg) or zinc hydroxy chloride (50, 75, and 100 mg/kg). An additional group of zinc-methionine supplement at 124 mg/kg was also included. Results showed that different levels of zinc supplementation caused a significant improvement in eggshell resistance, eggshell percentage, feed conversion ratio, and Haugh unit compared to the control group. Adding organic and hydroxy sources of zinc significantly increased zinc contents in egg yolk, tibia bone, and blood. In addition, the treatments containing zinc supplements caused an increase in the antibody level against the Newcastle disease compared to the control (P < 0.05). Different levels and sources of zinc had no significant effect on eggshell thickness, specific gravity, and egg mass. Results showed that adding zinc in hydroxy chloride form at 100 mg/kg could improve performance indices, safety, and egg enrichment with zinc.

Effects of Different Levels of Dietary Zinc-Threonine and Zinc Oxide on the Zinc Bioavailability, Biological Characteristics and Performance of Honey Bees (Apis mellifera L.)

The experiment was conducted to investigate the effect of supplementary different levels of zinc-threonine (Zn-Thr) and zinc oxide (ZnO) on the Zn bioavailability, biological characteristics and performance of honey bees (Apis mellifera L.). The experiments were carried out with seven treatments in a completely randomized design with five replicates for each treatment. During the experiment, groups were fed a basal diet without extra zinc (10.4 mg Zn/kg diet), and it was used as the control diet and 3 levels of 20, 40, and 60 mg Zn/kg were added to the diet by ZnO and Zn-Thr sources. The results showed that different levels of organic Zn significantly increased Zn and Fe content in the carcass of caged bees compared to different levels of inorganic Zn and control groups. Also, honey bees fed with levels of 40 and 60 mg Zn/kg Zn-Thr supplementation significantly had lower Malondialdehyde (MDA) concentration and higher ash content, protein content, superoxide dismutase (SOD) activity in their tissues. In addition, they showed more life span, feed intake, population, brood rearing, and hive weight gain (p < 0.05). Totally, the results of the present experiments revealed that diets supplied with organic Zn compared to inorganic Zn play significant roles in the improvement of Zn bioavailability, biological characteristics, and performance in honey bees.

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.

In vitro investigation of monoglycerides and zinc glycinate: anti-inflammatory and epithelial barrier function

The objectives of this study were to investigate the in vitro immune-modulatory effects of monoglycerides and zinc glycinate with porcine alveolar macrophages (PAM) and their impact on epithelial barrier integrity using the intestinal porcine enterocyte cell line (IPEC-J2). Cell viability was assessed using a Vybrant MTT assay to determine the appropriate dose range of monoglyceride blend (C4, C8, and C10) and zinc glycinate. In experiment 1, IPEC-J2 cells (5 × 105 cells/mL) were seeded and treated with each compound (monoglycerides: 0, 25, 100, 250, 500, and 1,000 µg/mL; zinc glycinate: 0, 2, 5, 12.5, 25, and 50 µg/mL). Transepithelial electrical resistance (TEER) was measured by Ohm's law method at 0 h (before treatment) and at 24, 48, and 72 h posttreatment. In experiment 2, PAM were collected from 6 clinically healthy piglets (7 wk of age) and seeded at 106 cells/mL. After incubation, the cells were treated with each compound and/or lipopolysaccharide (LPS). The experimental design was a 2 × 6 factorial arrangement with 2 doses of LPS (0 or 1 μg/mL) and 6 doses of each compound (monoglycerides: 0, 50, 100, 250, 500, and 1,000 µg/mL; zinc glycinate: 0, 25, 50, 100, 250, and 500 µg/mL). Cell supernatants were collected to analyze the concentrations of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) by enzyme-linked immunosorbent assay kits. Data were analyzed by ANOVA using PROC MIXED of SAS with a randomized complete block design. IPEC-J2 cells treated with 250 or 1,000 μg/mL of monoglycerides, or 5 μg/mL of zinc glycinate had increased (P < 0.05) TEER values at 48 or 72 h posttreatment, compared with control. The LPS challenge increased (P < 0.05) the production of TNF-α and IL-1β from PAM. In the non-challenge group, 50 or 100 μg/mL of monoglycerides stimulated (P < 0.05) TNF-α and IL-1β production from PAMs. Treatment with 25 or 100 μg/mL of zinc glycinate also enhanced (P < 0.05) TNF-α production from PAM. In LPS-treated PAM, 1,000 μg/mL of monoglycerides increased (P < 0.05) IL-1β production, while zinc glycinate suppressed (P < 0.0001) the secretion of TNF-α and IL-1β at the doses of 100, 250, and 500 μg/mL. In conclusion, the results of this in vitro study indicate that monoglycerides positively affect the barrier function of the epithelium, while zinc glycinate may have strong immune regulatory benefits. Future animal studies will be required to verify their impacts on animal gut health, systemic immunity, and growth performance.

Meta-analysis of Zinc Supplementation on Laying Performance, Egg Quality Characteristics, and Blood Zinc Concentrations in Laying Hens

There are inconsistent results on the influence of zinc (Zn) supplementation levels on productive indices of laying hens. This study, therefore, uses meta-analysis to synthesis evidence on the effect of inclusion of Zn in chicken diets on performance, egg quality, and blood Zn status of laying hens. Eleven studies were identified and used to analyze the effect of diets with or without Zn supplementation on feed intake, feed conversion ratio (FCR), hen day egg production (HDEP), egg weight (EW), egg mass (EM), Haugh unit (HU) scores, eggshell thickness (EST), eggshell weight (ESW), and blood Zn concentrations in laying hens. Data extracted from the 11 studies included in the meta-analysis were pooled using a random-effects model and expressed as standardized mean differences (SMDs) at a 95% confidence interval (CI). Results indicate that dietary Zn supplementation reduced FCR (SMD =  - 0.50 g feed/g egg; 95% CI: - 0.68 to - 0.31) and increased HDEP (SMD = 0.33%; 95% CI: 0.18 to 0.48), EW (SMD = 0.14 g; 95% CI: 0.03 to 0.25) and EM (SMD = 0.58 g/hen/day; 95% CI: 0.22 to 0.95), HU (SMD = 0.64; 95% CI: 0.42 to 0.85), EST (SMD = 0.84 mm; 95% CI: 0.45 to 1.23), and plasma Zn concentration (SMD = 4.20 mg/dl; 95% CI: 2.99 to 5.40) compared with the controls. In contrast, feed intake and ESW were not significantly different from controls. Restricted subgroup analysis indicated that chosen moderators (age of hen, inclusion level, chicken breed/strain, and supplementation duration) influenced the results of this meta-analysis. There was evidence of significant heterogeneity, and meta-regression indicated that moderators explained most of the sources of heterogeneity. We conclude that dietary zinc supplementation had positive effect on feed conversion ratio, laying performance, aspects of egg quality traits, and blood zinc concentrations in laying hens. The findings from this meta-analysis will help in policy advancements and sustainable use of zinc in the egg production industry.

Effects of supplementation of inorganic trace elements with organic trace elements chelated with hydroxy methionine on laying performance, egg quality, blood micronutrients, antioxidant capacity and immune function of laying ducks

Introduction

This study aimed to investigate the effects of organic trace elements chelated with hydroxy methionine (OTE-HM) in diets, which substituted inorganic trace elements, on laying performance, egg quality, blood microelement content, antioxidant capacity and immune function of laying ducks.

Methods

A total of 300 healthy laying ducks at age of 30 wk were randomly divided into 5 treatments and 10 ducks per replicate. The treatments included a control group (CON) which was served with basal diet supplemented with 20 mg/kg Cu, 50 mg/kg Fe, 70 mg/kg Mn, and 70 mg/kg Zn in inorganic form, and 4 OTE-HM treated groups (OTE-HM25, OTE-HM50, OTE-HM75, OTE-HM100) which were served with basal diets supplemented with OTE-HM providing trace elements (combination of Cu, Fe, Mn, Zn) at 25%, 50%, 75% and 100% of the commercial levels, respectively.

Results

Results showed that substitution of inorganic trace elements with OTE-HM did not affect egg production, qualified egg rate, average egg weight, average daily egg mass, average daily feed intake, or feed per kg egg of laying ducks (P &gt; 0.05). Dietary with OTE-HM did not influence eggshell strength, eggshell thickness, egg shape index, eggshell ratio, yolk ratio, albumen ratio, albumen height, and Haugh unit of the sampled eggs of ducks (P &gt; 0.05), but increased the yolk color, compared with dietary with inorganic trace elements (P&lt; 0.01). Moreover, the blood content of Cu of the laying ducks was significantly increased by OTE-HM compared with that in CON (P&lt; 0.001), but the other elements in laying duck blood were not different among treatments (P &gt; 0.05). OTE-HM (75% and 100%) significantly increased serum activities of glutathione peroxidase and Cu-Zn superoxide dismutase, and decreased serum content of malonaldehyde of laying ducks compared with those in CON (P&lt; 0.05). OTE-HM (50%, 75%, and 100%) significantly increased the serum contents of immunoglobulin G and immunoglobulin A of laying ducks compared with those in CON (P&lt; 0.05).

Discussion

Collectively, replacing inorganic trace elements with 50% and 75% OTE-HM in diets did not influence the laying performance or egg quality, but improved trace element efficacy, antioxidant capacity and immune function of the laying ducks.

Manganese-methionine chelate improves antioxidant activity, immune system and egg manganese enrichment in the aged laying hens

BACKGROUND

It has been reported that supplementation of manganese (Mn) could alleviate the negative effects of age on egg quality in laying hens. However, limited information is available on compensatory ways in order to reduce the adverse effects of hen age on health and Mn deposition in the body.

OBJECTIVES

The objectives were to investigate the effect of organic and inorganic sources of Mn on antioxidant activity, immune system, liver enzymes, shell quality and Mn deposition in the tissues of older laying hens.

METHODS

A total of 250, 80-week-old Leghorn laying hens (w36) were allocated into five treatment groups with five replications in a completely randomised design. Treatments were control (without Mn supplementation), 100% Mn sulphate, 75% Mn sulphate + 25% organic Mn chelate, 50% Mn sulphate + 50% organic Mn chelate and 25% Mn sulphate + 75% organic Mn chelate.

RESULTS

The groups fed 50 and 75% organic Mn chelate exhibited the lowest feed conversion ratio, as well as the maximum laying percentage, and egg weight and mass. Except to those fed 75% Mn sulphate, the hens received Mn supplements either as organic or inorganic, had higher immunoglobulin G and M compared with the control (p < 0.05). A significant elevation in the values of superoxide dismutase was observed in the hens receiving 50 and 75% organic Mn chelate when compared with the other treatments. The ALP activity decreased with increasing organic Mn chelate. Mn supplementation, either as organic or inorganic, increased Mn deposition in bone, egg yolk and shell, serum and liver.

CONCLUSION

Dietary supplementation with 50-75% Mn-methionine has the potential to replace Mn-sulphate in laying hens' diet for improving eggshell quality, Mn deposition in the eggshell, antioxidant capacity and immune response, as well as improving laying performance, egg weight and feed conversion ratio.

Zinc supplementation improves antioxidant status, and organic zinc is more efficient than inorganic zinc in improving the bone strength of aged laying hens

Background

There have been some reports indicating that supplementation of zinc could alleviate the negative effects of age on egg quality in laying hens. However, information regarding these positive effects on health and zinc deposition in the body is limited.

Objectives

The aim of the present study was to investigate the effect of organic and inorganic sources of zinc on the antioxidant activity, bone strength, and zinc deposition in the tissues of older laying hens.

Methods

In a completely randomized design, 175 Leghorn laying hens (w36) aged 80 weeks were allocated into seven treatment groups and five replications: control (without zinc supplementation), zinc sulphate treatments (15, 30, and 45 mg/kg), and organic zinc treatments (15, 30, and 45 mg/kg).

Results

There was a significant increase in feed intake in the zinc sulphate and organic zinc treatments compared to the control treatment (p < 0.05). The egg mass in organic and sulphate zinc showed a significant increase. The feed conversion ratio was decreased significantly in the organic zinc treatments (p < 0.05). Both organic and sulphate zinc supplements enhanced serum superoxide dismutase activity as an antioxidant index (p < 0.05). The cortical thickness of the tibia was improved in laying hens receiving 30 mg/kg organic zinc. Supplementation of zinc could lead to an increase in zinc deposition in tissues, and organic zinc boosts bone strength.

Conclusion

Zinc supplementation can improve antioxidant activity, feed intake, and feed conversion ratio and enhance egg mass and optimal absorption of zinc in tissues. The use of 30 mg/kg organic zinc is recommended for improving the cortical thickness of the tibia in aged laying hens.

Effects of Zinc Methionine Hydroxy Analog Chelate on Laying Performance, Serum Hormone Levels, and Expression of Reproductive Axis Related Genes in Aged Broiler Breeders

Inorganic zinc (Zn) supplements are commonly used in poultry feeds, but their low utilization results in the increase of Zn excretion. Thus, to provide a new perspective for the substitution of inorganic Zn, a novel Zn methionine hydroxy analog chelate (Zn-MHA) was studied in the present study to evaluate its effects on laying performance, serum hormone indexes and reproductive axis-related genes in broilers breeders. A total of 480 Hubbard breeders (56-week-old) were fed a basal diet (containing 27.81 mg Zn/kg) without Zn addition for 2 weeks, and then allocated to 4 groups with 6 replicates (each replicate consisting of 10 cages and 2 breeders per cage) for 10 weeks. Four treatment diets given to broiler breeders included the basal diet added with 25, 50, and 75 mg/kg of Zn-MHA and 100 mg/kg of Zn sulfate (ZnSO₄). The laying rate, egg weight and feed conversation ratio increased in the 75 mg/kg Zn-MHA group compared to the ZnSO₄ group. The eggshell thickness was not decreased with the addition of 50 mg/kg and 75 mg/kg Zn-MHA in the diet compared to the 100 mg/kg ZnSO₄ group. There was a significant improvement in the reproductive performance of breeders in the 75 mg/kg Zn-MHA group, including the fertility and 1-day-old offspring weight. Besides, serum sex hormone levels including FSH and P₄ increased significantly in 75 mg/kg Zn-MHA group. No significant effect on the ovarian weight or the number of follicles in broiler breeders was observed by supplementing Zn-MHA. Compared to the 100 mg/kg ZnSO₄ group, dietary supplementation with 75 mg/kg of Zn-MHA showed an up-regulation of the FSHR mRNA in the granular layer of follicles. However, dietary supplementation of Zn-MHA had no effects on mRNA expressions of the ovarian LHR and PRLR genes. These findings reinforce the suggestion that Zn-MHA (75 mg/kg) could replace ZnSO₄ (100 mg/kg) as a Zn supplement in diet of broiler breeders, which resulted in better laying and reproduction performances by regulating the expression levels of reproductive axis related genes and serum hormone levels.

Natural Products of Plants and Animal Origin Improve Albumen Quality of Chicken Eggs

Albumen quality is recognized as one of the major yardsticks in measuring egg quality. The elasticity of thick albumen, a strong bond in the ovomucin-lysozyme complex, and excellent biological properties are indicators of high-quality albumen. The albumen quality prior to egg storage contribute to enhance egg’s shelf life and economic value. Evidence suggests that albumen quality can deteriorate due to changes in albumen structure, such as the degradation of β-ovomucin subunit and O-glyosidic bonds, the collapse of the ovomucin-lysozyme complex, and a decrease in albumen protein-protein interaction. Using organic minerals, natural plants and animal products with antioxidant and antimicrobial properties, high biological value, no residue effect and toxicity risk could improve albumen quality. These natural products (e.g., tea polyphenols, marigold extract, magnolol, essential oils, Upro (small peptide), yeast cell wall, Bacillus species, a purified amino acid from animal blood, and pumpkin seed meal) are bio-fortified into eggs, thus enhancing the biological and technological function of the albumen. Multiple strategies to meeting laying hens’ metabolic requirements and improvement in albumen quality are described in this review, including the use of amino acids, vitamins, minerals, essential oils, prebiotics, probiotics, organic trace elements, and phytogenic as feed additives. From this analysis, natural products can improve animal health and consequently albumen quality. Future research should focus on effects of these natural products in extending shelf life of the albumen during storage and at different storage conditions. Research in that direction may provide insight into albumen quality and its biological value in fresh and stored eggs.

Low Level of Dietary Organic Trace Elements Improve the Eggshell Strength, Trace Element Utilization, and Intestinal Function in Late-Phase Laying Hens

This study was conducted to evaluate the effects of organic trace elements (Cu, Fe, Zn, and Mn) on performance, egg quality, trace elements utilization, and intestinal function in late-phase laying hens. A total of 1,080 laying hens (Hy-line brown, 65 weeks old) were randomly assigned to four treatments with six replications of 45 layers each. The basal diet was prepared without adding exogenous trace elements. The control group was fed with a basal diet supplemented with 600 mg/kg of inorganic trace elements. The three treatment groups were fed basal diets supplemented with 300, 450, and 600 mg/kg organic trace elements (OTE300, 450, and 600), respectively. The results showed that there was no significant difference in growth performance among all treatments. However, OTE450 significantly improved the eggshell strength of laying hens (p &lt; 0.05), but had no significant effects on haugh unit, egg yolk weight, eggshell weight, and eggshell thickness, compared with other groups. Moreover, compared with the control group, OTE450 significantly increased the contents of copper, iron, and zinc in serum (p &lt; 0.05). Meanwhile, all of the trace elements had a lower deposition in the feces in organic trace elements groups (p &lt; 0.05). Histological analysis showed that the addition of organic trace elements could significantly improve the villus height and villus concealment ratio (p &lt; 0.05). In addition, the messenger RNA (mRNA) and protein expressions of divalent metal transporter 1 (DMT1), zinc transporter 1 (ZnT-1), and ferroportin 1 (FPN1) were the highest in the OTE450 group. In conclusion, OTE450 could improve egg quality, intestinal function, and trace element utilization efficiency. Thus, this study provides a theoretical basis for the application of low levels of organic trace elements in laying hens.

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

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

Effect of dietary supplementation of zinc proteinate on performance, egg quality, blood biochemical parameters, and egg zinc content in White Leghorn layers

A study was conducted to investigate the effects of zinc proteinate (Zn-P) on laying performance, egg quality, antioxidant indices, and egg zinc content in laying hens from 38 to 49 weeks of age. A total of 150 White Leghorn layers were randomly assigned to five treatments, each with six replicates with five birds per replication. Dietary treatments included a corn-soybean meal-based basal diet with no zinc addition and basal diet supplemented with Zn-P at 40, 80, 120, or 160 mg/kg of feed for 12 weeks. The analyzed zinc concentrations of the five diets were 29.5, 70.8, 110.2, 147.5, and 187.5 mg Zn/kg, respectively. Dietary Zn-P supplementation had no effect on feed intake and egg production. However, raising the zinc level improved egg weight (P < 0.01) and egg mass (P < 0.05) and lowered the feed conversion ratio (P < 0.05) during the later (46-49 weeks) period. The Zn-P supplementation also significantly (P < 0.05) increased Haugh units, egg shell strength, and shell thickness and had no influence on other egg quality parameters. Increasing zinc levels in the diet resulted in increase in egg zinc contents and serum zinc level. The serum triglyceride and LDL-cholesterol levels significantly decreased (P < 0.05) in Zn-P-supplemented groups. Supplementation of Zn-P significantly (P < 0.05) increased serum Cu-Zn-SOD activity and reduced MDA concentration. It could be concluded that dietary supplementation of higher levels of Zn-P, more than 80 mg/kg diet, significantly improved the egg zinc content, some egg quality traits, antioxidant activity, and serum zinc levels.

Low levels of organic compound trace elements improve the eggshell quality, antioxidant capacity, immune function, and mineral deposition of aged laying hens

In the egg production industry, trace elements are required as additional dietary supplements to play vital roles in performance and egg quality. Compared to inorganic microelements (ITs), appropriate dose of organic trace microelements (OTs) are environmentally friendly and sufficient to satisfy the needs of hens. In order to evaluate the extent to which low-dose OTs replace whole ITs, the effects of organic copper, zinc, manganese, and iron compound on the performance, eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens were investigated. A total of 1 080 57-week-old Jing Hong laying hens were assigned to five groups with six replicates of 36 layers each for an 8-week experimental period. The birds were fed either a basal diet (control treatment (CT)) or the basal diet supplemented with commercial levels of inorganic trace elements (IT 100%) or the equivalent organic trace elements at 20%, 30%, and 50% of the inorganic elements (OT 20%, OT 30%, and OT 50%, respectively). Results showed that compared with those in the CT treatment, feeding hens with inorganic or organic microelement diet had significant effects on the eggshell quality, antioxidant capacity, immune function, and mineral deposition of old laying hens (P < 0.05). The eggshell strength and ratio between OT 30%, OT 50%, and IT 100% were similar at weeks 4 and 8, and the eggshell thickness of these groups was also similar at weeks 6 and 8. At week 8, the eggshell colour in OT 50% was darker than that in IT 100%. The mineral content in the eggshells of OT 50% and IT 100% significantly increased (P < 0.001), with no significant difference in effective thickness, mammillary thickness, and mammillary knob width between groups. There were no differences in the malondialdehyde content, total antioxidant capacity, and total superoxide dismutase activity in serum between OT 30%, OT 50%, and IT100%. While the catalase activities, the interleukin-1β, interleukin-10, immunoglobulin G, and immunoglobulin M concentrations in serum were not significantly different between OT 50% and IT 100%. The mineral contents in the faeces of the organic groups were considerably reduced compared with those in IT 100% (P < 0.001). In conclusion, dietary supplementation with 30-50% organic compound microelements has the potential to replace 100% inorganic microelements in the hen industry for improving eggshell quality, mineral deposition in the eggshell, antioxidant capacity, and immune function, and reducing emissions to the environment without negative effects on laying performance.

Hydroxychloride trace elements improved eggshell quality partly by modulating uterus histological structure and inflammatory cytokines expression in aged laying hens

The objectives of this study were to investigate the effectiveness of dietary zinc, copper, and manganese hydroxychloride (HC) supplementation on performance, minerals deposition, serum parameters, eggshell ultrastructure, uterus histological structure, and inflammatory cytokines in aged hens. A total of 560 Hyline Brown layers at 62 wk of age were randomly allotted into 3 groups (CON, basal diet without extra minerals supplemented; Sulphate and HC, basal diet with sulphate or hydroxychloride zinc, copper, and manganese supplementation at levels of 80, 15, and 80 mg/kg, respectively). The trial lasted for 16 wk consisting of 4 wk depletion period and 12 wk testing period. The results indicated that dietary hydroxychloride trace elements increased egg weight (P < 0.05) when compared with CON group and improved average Haugh unit and albumen height (P < 0.05) when compared with Sulphate group from 70 to 73 wk. Trace element supplementation significantly increased eggshell strength, ceruloplasmin content in serum, and modified crystallographic structure of eggshell (P < 0.05) that included effective layer height, palisade height, mammillary layer width, and mammillary internal area ratio, but the results did not differ regarding the trace mineral sources used. Furthermore, hens fed with hydroxychloride trace element showed the highest mucosal fold height (P < 0.05) and epithelial height (P = 0.053) in eggshell gland, as well as mRNA expression of TNF-α (P < 0.05) and IL-22 (P = 0.094). It is concluded that supplementation of Zn, Cu, and Mn mixture modified eggshell quality partly through enhancing histological structure and immune responses of uterus. Hydroxychloride source of Zn, Cu, and Mn excelled sulphate in its beneficial effects for birds.

Comparison of Zinc Sulfate and Zinc Threonine Based on Zn Bioavailability and Performance of Broiler Chicks

The purpose of this study was to compare zinc sulfate and zinc threonine chelate based on Zn bioavailability and performance of broiler chicks. The study was conducted in a completely randomized design with 256 day-old Ross 308 chicks and eight treatments including control treatment (no zinc supplementation), three levels of zinc sulfate and zinc threonine chelate (40, 80, and 120 mg zinc per kg feed), and a common commercial chelate (Bioplex Zn®) supply 40 mg zinc per kg feed. The results of total period showed that threonine chelate group had the highest live weight compared with other treatments and lowest feed conversion ratio belonged to 80 and 120 ppm of zinc threonine chelate (p < 0.05). Zinc threonine chelate and commercial chelate treatments had the lowest cholesterol and LDL levels compared with other treatments (p < 0.05). Zinc chelate threonine which contains 80 and 120 ppm of zinc had the highest HDL and superoxide dismutase enzymes and the lowest heterophile to lymphocyte ratio compared with other treatments (p < 0.05). Relative bioavailability of zinc threonine to zinc sulfate based on body weight, feed conversion ratio, cholesterol, LDL, HDL, superoxide dismutase enzyme, ash, and zinc content in tibia were 418.75, 173.91, 131.38, 159.43, 278.63, 193.45, 156.46, and 117.65%, respectively. According to the results of broiler performance and other traits measured in this study, it seems that the use of 80 ppm of zinc threonine chelate in the broiler diet is recommended in comparison with zinc sulfate levels and other threonine chelate levels.

Zinc Supplementation Forms Influenced Zinc Absorption and Accumulation in Piglets

The study aimed at determining the effect of different zinc (Zn) supplementation forms on Zn accumulation, activities of Zn-containing enzymes, gene expression of metallothionein (MT), and Zn transporters in piglets. Eighteen piglets were randomly divided into three groups: (a) a basal diet supplemented with 150 mg/kg Zn from Zn methionine (Zn-Met) in the feed (Zn-Met group), (b) a basal diet supplemented with 150 mg/kg Zn from Zn sulfate (ZnSO₄) in the feed (ZnSO₄, _feed group), and (c) a basal diet supplemented with the same dose of Zn as in ZnSO4,_feed group but in water (ZnSO₄, _water group). The results showed that Zn-Met added in feed and ZnSO₄ dissolved in drinking water significantly improved (p < 0.05) the Zn concentration in liver and jejunum and the apparent digestibility of Zn in comparison with the ZnSO₄ added in feed. In addition, dietary Zn supplementation as Zn-Met significantly increased (p < 0.05) the activity of alkaline phosphatase (AKP) in the jejunum of piglets in comparison with the ZnSO₄, _feed group. Furthermore, the Zn-Met and ZnSO₄, _water groups showed an improved total superoxide dismutase activity (T-SOD) in the ileum as compared to the ZnSO₄, _feed group. Meanwhile, the qPCR and western blot results showed that Zn-Met and ZnSO₄ dissolved in drinking water increased the expression of MT in the jejunum in comparison with the ZnSO₄ added in the piglets' feed. However, different Zn supplementation forms had no effect on the mRNA expressions of Zip4 and ZnT1 transporters. In conclusion, Zn-Met added in feed and ZnSO₄ dissolved in drinking water had higher bioavailability in piglets.