Zinc source modulates zootechnical characteristics, intestinal features, humoral response, and paraoxonase (PON1) activity in broilers

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.

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

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

Effects of dietary zinc chloride hydroxide and zinc methionine on the immune system and blood profile of healthy adult horses and ponies

The effects of dietary zinc on the immune function of equines have not been evaluated in detail so far. In the present study, eight healthy adult ponies and two healthy adult horses were fed a diet supplemented with either zinc chloride hydroxide or zinc methionine in six feeding periods of four weeks each (according to maintenance zinc requirement, 120 mg zinc/kg dry matter, and 240 mg zinc/kg dry matter, for both dietary zinc supplements, respectively). All animals received the six diets, with increasing amounts of zinc chloride hydroxide in the feeding periods 1-3, and with increasing amounts of zinc methionine in the feeding periods 4-6. At the end of each feeding period, blood samples were collected for a blood profile and the measurement of selected immune variables. Increasing dietary zinc chloride hydroxide doses increased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the erythrocyte lysate, decreased the numbers of total leukocytes and granulocytes in the blood, and also decreased the interleukin-2 concentrations in the plasma of the animals. The dietary supplementation of increasing doses of zinc methionine enhanced the mitogen-stimulated proliferative activity of peripheral blood mononuclear cells, and decreased the glutathione concentrations in the erythrocyte concentrate and the glutathione peroxidase activity in the plasma of the animals. The percentage of blood monocytes with oxidative burst after in vitro stimulation with E. coli decreased with increasing dietary zinc concentrations, independently of the zinc compound used. The blood profile demonstrated effects of the zinc supplements on the red blood cells and the bilirubin metabolism of the horses and ponies, which require further investigation. Overall, high doses of dietary zinc modulate the equine immune system, for the most part also depending on the zinc compound used.

Dietary organic zinc and probiotic alleviate induced Eimeria tenella infection in Japanese quails model of coccidiosis

The current study was conducted to evaluate the impact of organic zinc (OZn) and probiotic on growth performance, oocysts number, and histological features of cecum of quails following Eimeria tenella challenge. A total of 480 Japanese quails were distributed into six treatments as follows: untreated uninfected; untreated infected; E. tenella challenge + amprolium; E. tenella challenge + OZn; E. tenella challenge + probiotic; and E. tenella challenge + OZn + probiotic. Except untreated uninfected, all groups were orally gavaged at day 8 with 5 × 10⁴ E. tenella sporulated oocysts. Supplementation of OZn + probiotic improved (P = 0.001) growth performance compared to the untreated infected group. Lesion score of intestine and mortality was lower (P < 0.01) in quails supplemented with OZn + probiotic. Moreover, oocysts per gram (OPG) and histological dimensions of cecum in challenged birds were alleviated in OZn + probiotic. The histological findings of quails supplemented with OZn + probiotic showed normal intestinal villi with gentle sloughed epithelium. We concluded that OZn + probiotic may be safely included in the diet of Japanese quails to control coccidiosis.

Dietary trace mineral pattern influences gut microbiota and intestinal health of broilers

Dietary trace minerals can impact gut flora, which can further affect intestinal health. However, the dietary balance pattern of trace minerals for the intestinal health of broilers needs to be explored. The present study was conducted to investigate the effect of the dietary pattern of Cu, Fe, Mn, Zn, and Se on the intestinal morphology, microbiota, short-chain fatty acid concentrations, antioxidant status, and the expression of tight junction proteins in broilers. A total of 240 1-d-old Arbor Acres male broilers were randomly assigned to one of five treatments with six replicate cages of eight birds per cage for each treatment. The birds were fed the corn-soybean meal basal diet supplemented with five combination patterns of trace minerals for 42 d. The dietary treatments were as follows: the inorganic sources were added to the diet based on the recommendations of the current National Research Council (NRC, T1) and Ministry of Agriculture of P.R. China (MAP) (T2) for broiler chicks, respectively; the inorganic sources were added to the diet at the levels based on our previous results of inorganic trace mineral requirements for broilers (T3); the organic sources were added to the diet at the levels considering the bioavailabilities of organic trace minerals for broilers described in our previous studies (T4); and the organic sources were added to the diet based on the recommendations of the current MAP for broiler chicks (T5). The results showed that broilers from T1 had lower (P < 0.05) crypt depth (CD), and a higher (P < 0.05) villus height: CD in duodenum on day 21 and lower CD (P < 0.05) in jejunum on day 42 than those from T3 and T4. Broilers from T1, T3, and T5 had a higher (P < 0.05) Shannon index in cecum on day 21 than those from T4. Broilers from T1 had a higher (P < 0.05) abundance of Lactobacillus in ileum on day 21 than those from T2 and T3. Broilers from T1, T2, and T5 had a higher (P < 0.05) valeric acid concentrations in cecum on day 42 than those from T3 and T4. In addition, Birds from T2 had higher (P < 0.05) Claudin-1 mRNA levels in jejunum on day 42 than those from T3 and T4. And birds from T3, T4, and T5 had a higher (P < 0.05) Occludin protein expression levels in duodenum on day 42 than those from T2. These results indicate that dietary pattern of Cu, Fe, Mn, Zn, and Se influenced gut flora and intestinal health of broilers, and the appropriate pattern of Cu, Fe, Mn, Zn, and Se in the diet for intestinal health of broilers would be Cu 12 mg, Fe 229 mg, Mn 81 mg, Zn 78 mg, and Se 0.24 mg/kg (1 to 21 d of age), and Cu 11 mg, Fe 193 mg, Mn 80 mg, Zn 73 mg, and Se 0.22 mg/kg (22 to 42 d of age), when the trace minerals as inorganic sources were added to diets according to the recommendations of the current NRC.

Nano Zinc Oxide Improves Performance, IGF-I mRNA Expression, Meat Quality, and Humeral Immune Response and Alleviates Oxidative Stress and NF-κB Immunohistochemistry of Broiler Chickens

A 35-day trial was set to explore the effects of different dietary zinc sources on growth, insulin-like growth factor I (IGF-I) mRNA expression, meat quality, immune response, antioxidant activity, and immunohistochemistry of nuclear factor kappa B (NF-κ7B) of broiler chickens. Ross 308 broiler chicks (n = 156) were randomly assigned into four experimental groups. The G1 received the basal control diet without zinc supplementation; the G2, G3, and G4 were supplemented with zinc oxide, zinc lysine, and nano zinc oxide, respectively, at a level of 40 mg Zn/kg diet. The data revealed that nano zinc oxide linearly improved the overall growth performance parameters. Nano zinc oxide linearly elevated (P < 0.001) mRNA expression of IGF-I followed by G3. The pH value of breast muscle in G4 shows a linearly decreasing value (P < 0.001). Also, the linearly highest expressible release volume percentage and lightness (L*) value with the lowest redness (a*) value (P < 0.05) were recorded in G4 and G3. A numerical increase in the total antibody titer was recorded on the 35^th day in the G3 and G4. A numerical elevation in the superoxide dismutase (SOD) and a numerical reduction in the serum malondialdehyde (MDA) were recorded in the G4. The section of the liver from G4 revealed significantly very low expression of NF-κB staining. It is concluded that nano zinc oxide is considered the more trending zinc source. It had no negative effects on the health status and can be used in broiler diet premix.

Effects of dietary supplementation of myco-fabricated zinc oxide nanoparticles on performance, histological changes, and tissues Zn concentration in broiler chicks

A five weeks biological experiment was planned to investigate the impacts of dietary supplementation with zinc oxide nanoparticles (ZnONPs) synthesized by the endophytic fungus Alternaria tenuissima on productive performance, carcass traits, organ relative weights, serum biochemical parameters, histological alteration in some internal organs and concentration of this element in the serum, liver, thigh and breast muscle in broiler chicks. A total of 108 3-day-old commercial broiler chicks (Cobb 500) were individually weighed and equally distributed in a completely randomized design arrangement according to the dose of ZnONPs supplementation into 3 dietary experimental groups. There were 6 replications having 6 birds per replicate (n = 36/ treatment) for each treatment. The three experiential dietary treatments received corn-soybean meal-based diets enhanced with 0 (control), 40 and 60 mg/kg diet of ZnONPs respectively with feed and water were provided ad libitum consumption through 5 weeks life span. Present results indicated that after 5 weeks of feeding trial and as compared to control, the ZnONPs supplementation groups recorded higher body weight, improved feed consumption, feed conversion ratio and performance index. Serum biochemical analyses revealed that serum cholesterol, triglyceride, low density lipoprotein and uric acid decreased significantly, while high density lipoprotein and liver enzyme concentrations were increased significantly. Meanwhile, zinc accumulation in serum, liver and breast and thigh muscle were linearly increased with increasing zinc supplementation. It could be concluded that supplementation of ZnONPs to broiler diet at 40 or 60 mg/kg improved productive performance, birds' physiological status and the lower levels Zn (40 mg/kg diet) revealed promising results and can be used as an effective feed additive in broilers.

Zinc oxide nanoparticles induce dose-dependent toxicosis in broiler chickens reared in summer season

This research evaluates the effect of dietary zinc oxide nanoparticles' (ZnO NPs) supplementation on growth performance, immunity, oxidative antioxidative properties, and histopathological picture of broiler chicken reared in the summer season. A total of 224 1-day-old male Cobb chicks were randomly allocated to seven groups of dietary treatments (n = 32). Seven isocaloric and isonitrogenous diets were formulated. ZnO NPs were added to the basal diet at seven different levels, 0, 5, 10, 20, 40, 60, and 80 ppm/kg diet, respectively, for 35 days. Results indicated that live body weight (g) did not differ significantly (P > 0.05) between treatment groups, whereas compared to control, the 5 ppm ZnO NPs/kg diet recorded the highest live body weight at 21 and 35 days. No significant effects for the feed consumption (g/bird/period) and feed conversion ratio (g feed/g gain) among treated and control birds were observed. Hematological and immunological variables showed significant (P ≤ 0.05) dose-dependent modulations by ZnO NP supplementation. Significant (P ≤ 0.05) differences were observed in the phagocytic activity, phagocytic index, and IgM and IgG between the treatment groups, with the 5 and 10 ppm ZnO NPs/kg diet recording the best values, followed by the 20 ppm ZnO NPs/kg diet. Different supplementations had nonsignificant effects on the digestibility of nutrients (P ≤ 0.05). Histopathological pictures of the kidney, liver, and lymphoid organs, ultrastructural examination of muscle tissues, and expression of inflammatory cytokines showed dose-dependent morphological and structural changes. In conclusion, the ZnO NP supplementation in broiler diet to eliminate the heat stress hazards in summer season is recommended in dose level of not more than 10 ppm/kg diet.

Tomato pomace waste as safe feed additive for poultry health and production – a review

Tomato cultivation and industrial processing produce a considerable amount of tomato pomace, peels, and seeds, which are difficult to handle. These by-products contain a variety of minerals and bioactive substances, and may thus be further valorized, generating additional revenue for processing plants while also decreasing environmental issues caused by their buildup. The inclusion of tomato pomace in poultry feed has been shown to produce promising effects in poultry growth and health, however the results are largely inconsistent. Literature has documented improvement in growth, egg production and quality, immunological and antioxidant effects in poultry. This review has complied the impacts of tomato pomace on the growth and health indices of poultry.

Potential Applications of Moringa oleifera in Poultry Health and Production as Alternative to Antibiotics: A Review

Because of developing bacterial resistance and increased public awareness of health and food safety problems, the use of antibiotics as growth promoters in the chicken industry has been outlawed. This problem has spurred the poultry industry and sector to explore for safe antibiotic alternatives and to focus on developing better long-term feed management solutions in order to improve chicken health and growth. As a result, phytogenics have developed as natural antibiotic alternatives, with a lot of potential in the poultry industry. Moringa oleifera has gotten a lot of attention from researchers in the recent past as a natural product with a lot of health advantages for poultry. Moringa is known for its antimicrobial, antioxidant, anti-inflammatory, and hypocholesterolemic properties, as well as its capacity to activate digestive enzymes in the stomach, owing to the presence of hundreds of essential ingredients. The potential influence of M. oleifera as a natural feed supplement on overall gut health, nutritional digestibility, blood biochemical profile, antioxidant benefits, antibacterial potential, and immunological response is emphasized in this review.

Effects of Dietary Zinc Sources on Growth Performance and Gut Health of Weaned Piglets

The present study aimed to investigate the effects of dietary zinc sources on the growth performance and gut health of weaned piglets. In total, 96 Duroc × Landrace × Yorkshire (DLY) weaned piglets with an initial average body weight of 8.81±0.42kg were divided into four groups, with six replicates per treatment and four pigs per replicate. The dietary treatment groups were as follows: (1) control group, basal diet; (2) zinc sulphate (ZnSO4) group, basal diet +100mg/kg ZnSO4; (3) glycine zinc (Gly-Zn) group, basal diet +100mg/kg Gly-Zn and (4) zinc lactate group, and basal diet +100mg/kg zinc lactate. The whole trial lasted for 28days. Decreased F/G was noted in the Gly-Zn and zinc lactate groups (p<0.05). The zinc lactate group had a lower diarrhea rate than the control group (p<0.05). Moreover, the ZnSO4, Gly-Zn, and zinc lactate groups had significantly higher apparent total tract digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude ash, and zinc than the control group (p<0.05). The Gly-Zn and zinc lactate groups had higher jejunal villus height and a higher villus height:crypt depth ratio than the control group (p<0.05). In addition, the ZnSO4, Gly-Zn and zinc lactate groups had a significantly lower mRNA expression level of jejunal ZRT/IRT-like protein 4 (ZIP4) and higher mRNA expression level of jejunal interleukin-1β (IL-1β) than the control group (p<0.05). The mRNA expression level of jejunal zinc transporter 2 (ZNT2) was higher and that of jejunal Bcl-2-associated X protein (Bax) was lower in the Gly-Zn and zinc lactate groups than in the control group (p<0.05). Moreover, the zinc lactate group had a higher count of Lactobacillus spp. in the cecal digesta and higher mRNA expression levels of jejunal occludin and mucin 2 (MUC2) than the control group (p<0.05). In conclusion, dietary supplementation with 100mg/kg ZnSO4, Gly-Zn, or zinc lactate could improve the growth performance and gut barrier function of weaned piglets. Dietary supplementation with organic zinc, particularly zinc lactate, had the best effect.

Supplementation with an Inorganic Zinc Source in the Metalloproteomic Profile of Royal Jelly in Apis mellifera L

This study aimed to evaluate the quality of royal jelly produced by honeybees Apis mellifera supplemented with different concentrations of inorganic zinc (zinc sulfate monohydrate-0, 25, 50, and 75 ppm). Two-dimensional electrophoresis for the fractionation of royal jelly proteins was performed, and the zinc level was quantified by the flame atomic absorption spectrometry (FAAS) technique. Proteins were identified by electrospray ionization mass spectrometry (ESI MS MS). Analysis of variance followed by the Tukey test (P < 0.05) was used. Supplementation with the mineral zinc positively affected the quantification of proteins for treatments 50 and 75 ppm. However, all treatments independent of zinc concentrations showed fewer protein spots when compared to the control. All zinc-containing proteins were classified as major royal jelly proteins (MRJPs). The exposure of nursing bees to the mineral zinc in its inorganic form reduced the expression of six different MRJPs involved in larval and glands development of nursing bees (MRJP1, MRJP2, MRJP3, MRJP5, and MRJP7), however promoted an increase in the expression of royal jelly proteins involved in defense systems (MRJP8 and MRJP9). The results demonstrate that vital proteins and metabolic processes are impaired in nursing bees exposed to the mineral zinc in its inorganic form in all doses used affecting nutrition and maintenance of colonies.

Recent Advances in Understanding the Influence of Zinc, Copper, and Manganese on the Gastrointestinal Environment of Pigs and Poultry

Simple Summary

Pigs and poultry, similar to humans, need regular consumption of zinc, copper, and manganese for normal functioning. To ensure adequate dietary intake, and prevent deficiency, their diets are supplemented with sufficient, often excessive, levels of these minerals or even at higher levels, which have been associated with improvements in their health and/or growth. However, if provided in excess, mineral quantities beyond those required are simply excreted from the animal, which is associated with negative consequences for the environment and even the development of antimicrobial resistance. Therefore, it is of great interest to better understand the dynamics of zinc, copper, and manganese in the intestine of pigs and poultry following consumption of supplemented diets, and how the requirements and benefits related to these minerals can be optimized and negative impacts minimized. The intestine of pigs and poultry contains vast numbers of microorganisms, notably bacteria, that continually interact with, and influence, their host. This review explores the influence of zinc, copper, and manganese on these interactions and how novel forms of these minerals have the potential to maximize their delivery and benefits, while limiting any negative consequences.

Abstract

Zinc, copper, and manganese are prominent essential trace (or micro) minerals, being required in small, but adequate, amounts by pigs and poultry for normal biological functioning. Feed is a source of trace minerals for pigs and poultry but variable bioavailability in typical feed ingredients means that supplementation with low-cost oxides and sulphates has become common practice. Such trace mineral supplementation often provides significant ‘safety margins’, while copper and zinc have been supplemented at supra-nutritional (or pharmacological) levels to improve health and/or growth performance. Regulatory mechanisms ensure that much of this oversupply is excreted by the host into the environment, which can be toxic to plants and microorganisms or promote antimicrobial resistance in microbes, and thus supplying trace minerals more precisely to pigs and poultry is necessary. The gastrointestinal tract is thus central to the maintenance of trace mineral homeostasis and the provision of supra-nutritional or pharmacological levels is associated with modification of the gut environment, such as the microbiome. This review, therefore, considers recent advances in understanding the influence of zinc, copper, and manganese on the gastrointestinal environment of pigs and poultry, including more novel, alternative sources seeking to maintain supra-nutritional benefits with minimal environmental impact.

Protective Effect of Grape (Vitis vinifera) Seed Powder and Zinc-Glycine Complex on Growth Traits and Gut Health of Broilers Following Eimeria tenella Challenge

The current study was conducted to evaluate the impact of grape (Vitis vinifera) seed powder and zinc-glycine complex on growth parameters and cecal health of broiler following Eimeria tenella challenge. A total of 250 day-old male broilers (Hubbard) were distributed into five treatments as follows: I-negative control (basal diet); II-positive control (E. tenella challenge); III-group infected + Amprolium; IV-group coccidial infection + organic zinc (OZ) at 50 ppm + grape seed powder (GSP) at 2.5 g/kg; V-coccidial infection + organic zinc (OZ) at 50 ppm + grape seed powder (GSP) at 5.0 g/kg. From findings, a lower (p < 0.05) feed intake was noted for positive control compared to the other treatment groups. Conversely, higher (p < 0.05) body weight, dressing percentage, and feed conversion ratio were observed in infected + Amprolium, GSP2.5 + OZ50, and GSP5 + OZ50 treatments in comparison to the positive control. Moreover, the positive control showed severe cecal lesions of thickness and hemorrhages with mild congestion. The lesion scores decreased (p < 0.05) in GSP and OZ treated groups compared to the positive control. Significant (p < 0.05) lower oocyst per gram of feces was found in infected + Amprolium, GSP2.5 + OZ50, and GSP5 + OZ50 in comparison to positive control. Supplementing diet with GSP and OZ at both levels showed restoration of intense sloughing of villi. From the present findings, it can be concluded that OZ and grape seed powder positively ameliorated the growth performance, lesion score, and oocysts shedding in broilers infected with E. tenella.

Paraoxonase Role in Human Neurodegenerative Diseases

The human body has biological redox systems capable of preventing or mitigating the damage caused by increased oxidative stress throughout life. One of them are the paraoxonase (PON) enzymes. The PONs genetic cluster is made up of three members (PON1, PON2, PON3) that share a structural homology, located adjacent to chromosome seven. The most studied enzyme is PON1, which is associated with high density lipoprotein (HDL), having paraoxonase, arylesterase and lactonase activities. Due to these characteristics, the enzyme PON1 has been associated with the development of neurodegenerative diseases. Here we update the knowledge about the association of PON enzymes and their polymorphisms and the development of multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD).

Effect of zeolite supplementation on the dynamics of some trace elements and pigmentation of rumen in growing lambs

A study was conducted to investigate the effect of feeding complete feed as total mixed ration (TMR) with two levels of zeolite on copper (Cu), iron (Fe), and zinc (Zn) status and rumen color of growing Naemi lambs. Twenty-four growing lambs (25 ± 2.1 kg body weight) were individually kept in separate pens with ad libitum feed and water. The lambs were randomly distributed to three treatments as follow: control, TMR diet only; T1, TMR with 1% zeolite daily; T2, TMR with 2% zeolite daily. The trial was lasted for 56 days. Four lambs from each treatment were slaughtered and tissue (liver, kidney, meat, and rumen tissues) and rumen fluid samples were collected. A significantly (P < 0.05) high concentration of Fe was found in T2 in blood and rumen fluid samples of lambs supplemented with zeolite. In the meat tissue, significantly (P < 0.05) high concentration of Zn was found in the treatment groups compared with the control, while Cu concentration decreased significantly (P < 0.05) in T1. In addition, rumen dark color was reduced in the zeolite-supplemented groups. We concluded that supplementation of zeolite at the rate of 1 or 2% did not appear to have any adverse effects on the blood profile of trace elements. Moreover, under these two levels of zeolite, discoloration of the rumen was significantly reduced in response to the supplementation of zeolite.