Estimation of the Relative Bioavailability of Several Zinc Sources for Broilers Fed a Conventional Corn-Soybean Meal Diet

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.

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.

Worldwide Research Trends for Chelates in Animal Science: A Bibliometric Analysis

The purpose of this study was to look at research trends in the application of CTM in animal nutrition in order to identify current and emerging challenges, as well as to examine the intellectual structure of the subject. The intellectual structure of CTM was examined using keyword and reference analysis. The research community includes all research and review articles published in journals indexed in the Web of Science database during the years 1990-2022. The results showed that the terms zinc, co-occurring 331 times, performance (324 times), and copper 216 (times) were the main and hotspots of research in the field of chelate. The data suggest that the most important keywords during the study period were zinc, copper, pig, bovine, metabolism, and bioavailability. The terms health, muscle, beef, trace elements, and dietary supplements represent emerging topics in CTM, as research began to focus on these areas during the years 2017-2022. The country with the greatest number of published articles was the United States of America. This bibliometric analysis showed that countries are focusing on the effects of CTM on the health and musculature of cattle through dietary supplementation with trace elements. According to the identified hot and emerging topics, this research can serve as a roadmap for a global comprehensive scientific plan and policy.

Potentials of Dietary Zinc Supplementation in Improving Growth Performance, Health Status, and Meat Quality of Broiler Chickens

The demand for chicken meat is on the rise, necessitating high level of production and efficient feed conversion which to a certain extent can be actualized by the use of specific trace minerals like zinc (Zn). Zn is a part of several enzymes involved in the metabolism of protein, fat, carbohydrates, and nucleic acids. In addition, Zn has antioxidant properties and is vital for hormone function, including growth, pancreatic, and sex hormones. Its deficiency in animals is characterized by poor fertility, decreased feed intake, poor growth, testicular atrophy, and weakened immunity. Nano-Zn sources have been shown to be more bioavailable than conventional zinc (organic and inorganic) sources. Zn from organic sources, on the other hand, has higher bioavailability than Zn from inorganic sources. Furthermore, Zn supplementation promotes growth, enhances antioxidant capacity, modulates the immunity, and improves health indices in broiler chickens. Published studies have demonstrated that Zn supplementation has the potential to improve carcass yield and meat quality in broilers with various research contradictions. However, a clear understanding of the role of Zn in broiler nutrition is still lacking, necessitating further research. As a result, the purpose of this review was to highlight the influence of Zn (organic or inorganic) supplementation on growth, blood characteristics, antioxidant status, immune responses, Zn tissue/fecal concentrations, intestinal villus histomorphology, and meat quality of broiler chickens as well as Zn bioavailability to understand the role of Zn in broiler nutrition, resolve contradictory research results, and identify knowledge gaps. Understanding the role of dietary Zn in broiler chicken nutrition and meat quality will avail important suggestion on policy advancements and sustainable use of Zn in the broiler chicken industry.

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.

A perspective review on the effect of different forms of zinc on poultry production of poultry with special reference to the hazardous effects of misuse

Zinc (Zn) is a unique micro-mineral because it is an essential component in many enzymes such as superoxide dismutase, carbonic anhydrase, and alkaline phosphatase, as well as being important for regulation of proteins and lipids metabolism, and sex hormones. This mineral is applied in poultry production in three forms; inorganic, organic, and nanoparticle form. The nano-form of Zn is preferable in application to other conventional forms with regard to absorption, bioavailability, and efficacy. Broilers fed on diets supplemented with Zn showed improvement of growth performance, carcass meat yield, and meat quality. In addition, Zn plays an important role in enhancing of both cellular and humeral immune responses, beside its antimicrobial and antioxidant activities. In laying hens, dietary addition of Zn improves the eggshell quality and the quantity of eggs. Moreover, Zn has a vital role in breeders in terms of improving the egg production, fertility, hatchability, embryonic development, and availability of the hatched chicks. Therefore, this review article is focused on the effects of using Zn on the performance and immunity of poultry, as well as its antimicrobial and antioxidant properties with special reference to the hazardous effects of the misusing of this mineral.

Intestinal digestibility of selected minerals, growth performance and meat quality in turkeys fed diets supplemented with different sources and levels of zinc

The aim of this study was to determine whether dietary supplementation with zinc oxide nanoparticales (NP-ZnO) as a substitute for the conventional ZnO affects the intestinal digestibility of selected minerals, growth performance and meat quality in turkeys. The replacement of ZnO with NP-ZnO had no effect on the intestinal digestibility of Zn, Cu, Fe and Ca, whereas the lowest dose of supplemental Zn reduced Zn digestibility. The applied inclusion levels and sources of Zn had no effect on the growth performance (except the feed intake) of turkeys, including liveability. No differences in the relative weights of the heart, spleen and bursa of Fabricius (except the liver), or the weights of the femur and tibia were found between the dietary treatments. Neither the dose nor the source of supplemental Zn influenced carcass dressing percentage or the share of breast, thigh and drumstick muscles in the carcass. In comparison with the highest and moderate doses of Zn, the lowest inclusion level of Zn contributed to increased yellowness of breast meat (P=0.005). The analyzed doses and sources of supplemental Zn exerted varied effects on the redox status of fresh and frozen breast meat. In conclusion, the growth performance of turkeys, carcass yield and composition as well as the redox status of fresh and frozen breast meat were generally similar, regardless of the dietary source and level of Zn. The beneficial effect of Zn addition at 100 mg/kg was improved Zn and Ca digestibility, and increased redness of breast meat.

Nano-sized Zinc in Broiler Chickens: Effects on Growth Performance, Zinc Concentration in Organs, and Intestinal Morphology

The effects of dietary supplementation of zinc (Zn) sources and concentrations were investigated on growth performance, absorption into tissues, fecal excretion, nutrient retention, and intestinal morphology in broilers fed a corn-soybean meal basal diet. A total of 525 one-day-old chicks (Ross 308) were assigned based on body weight to seven dietary treatments. There were five replicate pens for each treatment and 15 broilers per replicate pen. The dietary treatments included a basal diet (control, without supplementing Zn), and basal diet supplemented with Zn, as inorganic zinc sulfate (ZnS; 110 mg/kg); organic Zn-methionine (ZnM; 110 mg/kg); hot-melt extruded (HME) 25 zinc sulfate (27.5 mg/kg); HME50 zinc sulfate (55 mg/kg); HME75 zinc sulfate (82.5 mg/kg); or HME100 zinc sulfate (110 mg/kg) for 35 days in two phases (d 1-21, phase I and d 22-35, phase II). Bodyweight and feed efficiency of broiler chicks fed diets supplemented with increasing dietary concentrations of HME-Zn improved linearly during the study period (P<0.05). Compared to the control treatment, the ZnS, ZnM, and HME diets increased Zn concentrations in the serum and liver. Inorganic ZnS supply resulted in the highest Zn concentration in excreta. Increasing supplemented Zn content in diets as HME linearly increased Zn concentration in the excreta, serum, liver, and tibia. Broiler chicks fed diets supplemented with increasing concentrations of HME increased villus height (VH; linear and quadratic) of the jejunum and VH of the ileum (linear). Increasing concentrations of dietary Zn supplied as HME resulted in linearly enhanced dry matter, gross energy, and nitrogen retention of broilers on day 21. These results suggest that dietary HME-Zn at a lower level (55 ppm) shows the same growth performance as common ZnSO₄ at 110 ppm.

Effects of Replacing Inorganic with Respective Complexed Glycinate Minerals on Apparent Mineral Bioavailability and Deposition Rate in Tissues of Broiler Breeders

The study was conducted to evaluate the effects of replacing inorganic trace minerals (ITMs) with respective low-dose complexed glycinate minerals (CGMs) on their bioavailability and retention during peak laying period of broiler breeders. In this experiment, 648 ZhenNing broiler breeders (23 weeks old) were randomly allocated to four treatments with six replicates (27 birds/replicate) and fed for 14 weeks including 2 weeks adaptation period. The treatments were T1-ITM, commercially recommended levels of ITMs (Cu, Zn, Fe, and Mn sulphates); T2-MIX, half of the minerals were supplemented with ITMs and half with CGMs; T3-L-CGMs, minerals were supplemented with CGMs (50% level of T1); and T4-M-CGMs, minerals were supplemented with CGMs (70% level of T1). The results showed that birds fed on ITM had lower bioavailability of Fe, Mn, and Zn (P < 0.05) than those fed on L-CGMs, but the highest (P < 0.01) bioavailability of Cu was found in those fed on MIX. Mineral retention (in serum, muscle, bone, and tissues) was not affected by reducing supplementation levels of trace minerals up to 50% of ITMs, but Zn (in serum, liver, kidney, heart, and albumen) and Fe (in serum and the yolk) retention was negatively affected (P < 0.05). In conclusion, replacing dietary ITMs with low-dose complexed glycinate minerals increases the apparent bioavailability of Fe, Mn, and Zn without compromising the mineral retention rates in most of the tissues tested.

Effect of dietary zinc pectin oligosaccharides chelate on growth performance, enzyme activities, Zn accumulation, metallothionein concentration, and gene expression of Zn transporters in broiler chickens1

This study was to investigate the effect of zinc pectin oligosaccharides chelate (Zn-POS) on growth performance, serum enzyme activities, tissue zinc accumulation, metallothionein (MT) concentrations, and gene expression of zinc transporters (ZnT) in broilers. Five hundred forty 1-d-old Arbor Acres broiler chicks were randomly assigned to 5 dietary groups with 6 replicates of 18 birds per replicate. The diets were formulated with the same supplemental Zn level (80 mg/kg diet) but different amount of the Zn-POS: 0, 200, 400, 600, and 800 mg Zn-POS/kg diet. ZnSO4 was used to adjust to the desired amount of the Zn (80 mg/kg) in the Zn-POS diets. Broilers were fed with the experimental diets for 42 d including the starter (days 1 to 21) and grower (days 22 to 42) phases. Our results showed that dietary supplementation of Zn-POS linearly and quadratically increased (P < 0.05) the average daily gain and gain-to-feed ratio during 22 to 42 d and 1 to 42 d as well as body weight on day 42, whereas reduced (P < 0.05) the sum of mortality and lag abnormalities in broilers on day 42. Besides, serum alkaline phosphatase and copper-zinc superoxide dismutase activities increased (P < 0.05) linearly and quadratically in response to dietary Zn-POS supplemental level on day 42. Dietary Zn-POS supplementation increased Zn accumulation in serum (linear, P < 0.05), liver (linear, P < 0.05), and pancreas (linear and quadratic, P < 0.05). In addition, Zn-POS supplementation linearly and quadratically increased (P < 0.01, P < 0.05, respectively) MT concentrations in liver and pancreas of broilers. Pancreatic mRNA levels of MT, ZnT-1, and ZnT-2 increased (P < 0.05) linearly and quadratically, and the mRNA expression of metal response element-binding transcription factor-1 increased linearly (P < 0.05), in response to dietary Zn-POS supplementation. In conclusion, supplementation of Zn-POS in the diet increases Zn enrichment in the metabolic organs such as liver and pancreas and promotes productive performance in broilers.

Feed Additives Produced on the Basis of Organic Forms of Micronutrients as a Means of Biofortification of Food of Animal Origin

In recent years, there has been a steadily growing demand for animal protein. Consumer awareness is also growing every year, which is why breeders are obliged to provide animals with the best possible environmental conditions that will determine the productivity of animals and the quality of raw materials obtained from them. Today's consumer is looking for not only the highest quality food but also the one that will characterize health-promoting properties. Therefore, food is sought, which will be characterized by a favorable profile of fatty acids and a high content of biologically active ingredients, such as vitamins or minerals. One of the most effective methods of enriching food with these ingredients is their supplementation in feed. However, it should be remembered that the form in which such a component will be delivered is very important. High hopes are associated with the possibility of using organic forms of macro- and micronutrients, which are sometimes better absorbed than inorganic salts. The aim of the work was to collect and systematize knowledge related to the possibility of enriching food of animal origin with micronutrients using additional feed containing these ingredients in organic form.

Growth Performance, Mineral Digestibility, and Blood Characteristics of Ostriches Receiving Drinking Water Supplemented with Varying Levels of Chelated Trace Mineral Complex

The effects of water supplementation of chelated trace minerals (CTM, which is named Bonzaplex designed with chelate compounds technology) on growth performance, apparent total tract digestibility (ATTD) of minerals, and some blood metabolites, TM, and antioxidant enzyme values in African ostriches were investigated from 8 to 12 months of age. A total of 20 8-month-old ostriches (five birds in five replicate pens) was randomly allocated into one of the following four treatments: (1) control (basal diet + tap water), (2) low CTM (basal diet +100 mg/bird/day CTM powder in tap water), (3) medium CTM (basal diet +1 g/bird/day CTM powder in tap water), and (4) high CTM (basal diet +2 g/bird/day CTM powder in tap water). Compared with control, medium CTM improved (P < 0.05) daily weight gain and ATTD of phosphorous, zinc, and copper in 12-month-old ostriches. Furthermore, the feed conversion ratio was lower, and ATTD of magnesium was higher in the medium- and high-CTM groups than that in the control group (P < 0.05). At the end of the trial, ostriches receiving high-CTM treatment exhibited the lower (P < 0.05) serum triglyceride and very low-density lipoprotein cholesterol concentrations and higher copper levels compared to those of the control treatment. Supplementation of higher amounts of CTM (medium and high CTM) also increased the activity of serum superoxide dismutase (P < 0.05). No differences were detected for other blood parameters including glucose, total protein, albumin, cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, iron, magnesium, and glutathione peroxidase values. In conclusion, supplementation of CTM at the level of 1 g/bird/day to the drinking water can be recommended for improving growth performance, mineral absorption, and antioxidant status of ostriches fed diets containing the recommended levels of inorganic TM.

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 dietary zinc oxide nanoparticles on growth performance and antioxidative status in broilers

Broilers in four groups were fed a basal diet supplemented with 60 mg/kg zinc oxide (60-ZnO; control), or 20, 60, or 100 mg/kg ZnO nanoparticles (20-, 60-, and 100-nano-ZnO, respectively). Compared with the controls, after 14 days, birds in the 20- and 60-nano-ZnO groups had significantly greater weight gains and better feed conversion ratios. However, the body weight of birds in the 100-nano-ZnO group was dramatically reduced after 28 days. Relative to the control group, the total antioxidant capability (T-AOC) in serum and liver tissue was significantly higher in the 20-nano-ZnO group at all time points and also significantly higher in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues on days 21 and 28. Compared with the controls, the activity of copper-zinc superoxide dismutase (Cu-Zn-SOD) was significantly greater in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues after 21 days. Catalase activity in serum samples was significantly higher in the 20- and 60-nano-ZnO groups relative to the control and 100-nano-ZnO birds, but catalase activity in liver tissue was not affected by different nano-ZnO levels. Malondialdehyde content in serum and liver tissues was significantly reduced in the 20-, 60-, and 100-nano-ZnO groups compared with that in the control group at all time points except day 42. Taken together, our data indicate that appropriate concentration of dietary ZnO nanoparticles improves growth performance and antioxidative capabilities in broilers, and 20 mg/kg nano-ZnO is the optimal concentration.