Effects of Various Copper Sources and Concentrations on Performance, Skeletal Growth, and Mineral Content of Excreta in Broiler Chickens

The experiment was designed to study the effect of supplemental sources and concentrations of copper on the performance and development and mineralization of tibia bones in broiler chickens. A 42-day feeding experiment was conducted utilising three copper sources, including copper sulphate (CuS), copper chloride (CuCl), and copper propionate (CuP), each with four different concentrations, i.e. 8, 100, 150, and 200 mg/kg. The body weight gain with 200 mg Cu/kg food was noticeably higher during the first 4-6 weeks of age. Due to the interaction between Cu sources and levels, there was no significant change in the body weight gained. The feed intake during various growing phases did differ significantly neither the main effect nor the interaction between different copper sources and levels. A CuP-supplemented diet (200 mg/kg food) considerably (P ≤ 0.05) improved the feed conversion ratio between 4-6 and 0-6 weeks. At the end of the experiment, a total of 72 tibia bones, i.e. six for each treatment were collected. A metabolic trial was conducted to look into mineral retention in broiler chickens on the final 3 days of the trial (40-42 days). Increased tibia bone zinc (Zn) levels were seen with the addition of 8 mg Cu/kg of Cu chloride, 100 mg Cu/kg of Cu propionate, 8 mg Cu/kg of Cu sulphate, and 8 mg/kg of Cu propionate to the diet. At higher levels of Cu (150 and 200 mg/kg diet), there was a significantly (P ≤ 0.01) reduced tibia Zn content. Cu sulphate treatment group had higher (P ≤ 0.01) tibia Cu content (8 mg Cu/kg diet). Cu sulphate supplemented diet had a greater excreta Zn content (P ≤ 0.01) than Cu chloride supplemented diet, and Cu propionate supplemented diet had the lowest excreta Zn content. Excreta with a higher Fe concentration were found in diets supplemented with copper sulphate and copper chloride (P ≤ 0.05) than in diets supplied with copper propionate. Thus, it may be concluded that feeding dietary Cu concentrations up to 200 mg Cu/kg diet, regardless of the different sources, had no negative effects on bone morphometry and mineralization parameters with the exception of a decrease in the tibia's zinc content.

Effect of small peptide chelated iron on growth performance, immunity and intestinal health in weaned pigs

BACKGROUND

Small peptide chelated iron (SPCI), a novel iron supplementation in pig diets, owns growth-enhancing characteristics. Although a number of researches have been performed, there is no clear-cut evidence to show the exact relationship between the dose and effects of small peptide chelated minerals. Therefore, we investigated the effect of dietary supplementation of SPCI at different doses in the growth performance, immunity, and intestinal health in weaned pigs.

METHODS

Thirty weaned pigs were randomly assigned into five groups and feed with basal diet or the basal diet containing 50, 75, 100, or 125 mg/kg Fe as SPCI diets. The experiment lasted for 21 d and on day 22, blood samples were collected 1 h later. The tissue and intestinal mucosa samples were collected following.

RESULTS

Our results showed that the feed to gain ratio (F:G) decreased with different levels of SPCI addition (P < 0.05). The average daily gain (ADG) (P < 0.05) and digestibility of crude protein (P < 0.01) decreased with 125 mg/kg SPCI addition. With dietary different levels of SPCI addition, the serum concentrations of ferritin (quadratic, P < 0.001), transferrin (quadratic, P < 0.001), iron content in liver (quadratic, P < 0.05), gallbladder (quadratic, P < 0.01) and fecal (quadratic, P < 0.01) increased quadraticly. While the iron content in tibia (P < 0.01) increased by 100 mg/kg SPCI supplementation. Dietary 75 mg/kg SPCI addition increased the serum insulin-like growth factor I (IGF-I) (P < 0.01) and SPCI (75 ~ 100 mg/kg) addition also increased the serum content of IgA (P < 0.01). The serum concentrations of IgG (quadratic, P < 0.05) and IgM (quadratic, P < 0.01) increased quadraticly by different levels of SPCI supplementation. Moreover, different levels of SPCI supplementation decreased the serum concentration of D-lactic acid (P < 0.01). The serum glutathione peroxidase (GSH-Px) (P < 0.01) elevated but the malondialdehyde (MDA) (P < 0.05) decreased by 100 mg/kg SPCI addition. Interestingly, SPCI supplementation at 75 ~ 100 mg/kg improved the intestinal morphology and barrier function, as suggested by enhanced villus height (P < 0.01) and villus height/crypt depth (V/C) (P < 0.01) in duodenum, as well as jejunum epithelium tight-junction protein ZO-1 (P < 0.01). Moreover, SPCI supplementation at 75 ~ 100 mg/kg increased the activity of duodenal lactase (P < 0.01), jejunal sucrase (P < 0.01) and ileal maltase (P < 0.01). Importantly, the expression levels of divalent metal transporter-1(DMT1) decreased with different levels of SPCI addition (P < 0.01). In addition, dietary SPCI supplementation at 75 mg/kg elevated the expression levels of critical functional genes such as peptide transporter-1(PePT1) (P = 0.06) and zinc transporter 1 (ZnT1) (P < 0.01) in ileum. The expression levels of sodium/glucose co-transporter-1 (SGLT1) in ileum (quadratic, P < 0.05) increased quadraticly by different levels of SPCI addition and amino acid transporter-1 (CAT1) in jejunum(P < 0.05) also increased by 100 mg/kg SPCI addition.

CONCLUSIONS

Dietary SPCI supplementation at 75 ~ 100 mg/kg improved growth performance by elevated immunity and intestinal health.

The Effects of Nano and Micro Particle Size of Zinc Oxide on Performance, Fertility, Hatchability, and Egg Quality Characteristics in Laying Japanese Quail

The current trial was conducted by using the 288 Japanese quails to evaluate the effects of a zinc-deficient diet supplemented with nano and micro zinc oxide on performance, fertility, hatchability, and egg quality characteristics. In this experiment, birds were randomly allocated to 9 dietary treatments includes diets supplemented with nano or micro particles of zinc oxide (amount of ZnO supplement for each treatment) to supply 49, 74, 99, and 124 mg zinc per kilogram of diet in a factorial arrangement (2 × 4) and a control non supplemented diet (24 mg/kg) with four replicates of eight birds (six females and two males) in each pen. Birds were fed the experimental diets from 47 to 75 days of age and had free access to water and feed during the experimental period. Results showed that Zn supplementation, regardless of particle size, improved the eggshell thickness (P < 0.01). A significant (P < 0.05) interaction was observed between zinc level and ZnO particle size for Shell breaking strength. Quails fed diets supplement with ZnO showed significantly higher egg weight and eggshell surface (P < 0.05) as compared with birds fed a non-supplemented control diet. Results obtained here showed that supplementation of nano ZnO enhanced fertility considerably. Application of non-linear quadratic models showed that the maximum egg production percentage was achieved when 67 or 72 mg/kg of dietary zinc was supplied from nano and micro ZnO, respectively. This result indicated that nano ZnO could reduce the zinc requirement in laying Japanese quail.

The effects of supplemental levels of inorganic zinc, manganese and copper on growth performance in commercial broilers

Commercial broiler premixes provide trace minerals (TMs) such as Zinc (Zn), Manganese (Mn) and Copper (Cu) above the birds' requirements to maximise broiler performance. High inclusion levels of TM and their low absorption in the broiler's gastrointestinal tract have led to increased TM levels in their litter, raising concerns about TM's accumulation in the environment from poultry litter. A 35-day broiler trial was conducted at a broiler facility with 2 880-day-old Cobb 500 broiler males. The objective was to evaluate whether decreasing inorganic Zn, Mn and Cu levels in broiler diets would have a negative effect on broiler growth parameters such as BW, average daily gain, cumulative feed intake (FI) and feed conversion ratio (FCR). Consequently, these minerals were supplemented at 100%, 50%, 25%, and 0% of the Cobb standards. No significant difference in FI and FCR was observed between the treatments for the first 21 days, and there were no significant differences in BW between the positive control, negative control (NC), and 50% of Cobb recommended levels at day 35. However, BW for the NC was significantly higher than the 25% level. These results show that reducing TM levels in broiler diets below commercially recommended levels had no negative effect on broiler performance, with the subsequent economic benefits for producers.

Effects of dietary supplementation of iron as sulphates or glycine chelates on the productive performance and concentrations of acute-phase proteins and iron in the serum and liver tissues of broiler chickens

The aim of the study was to determine the effects of inorganic (ferrous sulfate [FeSO4] and FeSO4 + phytase [FeSO4+F]) and organic forms of iron (ferrous glycine chelate [FeGly], Fe-Gly + phytase [Fe-Gly+F]) on the concentrations of C-reactive protein (CRP), serum amyloid A (SA), alpha- 1-acid glycoprotein (α-AGP), haptoglobin (Hp), transferrin (TRF) and iron in the blood and liver tissue of poultry. Ross 308 roosters were used in this study. The acute-phase protein (AP) levels in the chicken serum and liver tissues were assayed using the double-antibody sandwich ELISA kits for chickens. The iron levels in serum and liver samples were measured using flame atomic absorption spectrophotometry. The results showed that the serum and hepatic iron concentration in the chickens receiving Fe-Gly and Fe-Gly-F were significantly higher than those in the control group and in the chickens receiving iron in the form of sulphates. Further, serum CRP and SA concentrations were lower in the chickens from the supplemented groups than in those from the control. The hepatic CRP concentration was higher in the supplemented groups than in the control group. The serum and hepatic TRF concentration were highest in the chickens receiving FeSO4 and FeSO4-F. The hepatic Hp concentration was higher in the chickens receiving organic forms of iron than in the control chickens, whereas the serum Hp concentrations were similar across the groups. The highest α-1-AGP concentration was found in the livers of the chickens receiving Fe- Gly and Fe-Gly-F. Taken together, these findings suggest that iron had the most beneficial effects for poultry in terms of health, performance and immunity when added to the feed in the form of glycine chelate.

Endogenous enzyme activities and tibia bone development of broiler chickens fed wheat-based diets supplemented with xylanase, β-glucanase and phytase

Objective

This study assessed the effect of different levels of xylanase, β-glucanase and phytase on intestinal enzyme activities and tibia bone development in broiler chickens fed wheat-based diets.

Methods

Twelve experimental diets were formulated using a 3×2×2 factorial design (three doses of phytase and two doses of both xylanase and β-glucanase) and offered to 648 day-old Ross 308 male chicks having 6 replicates groups with 9 birds per replicate and lasted for 35 days.

Results

An interaction between the enzymes products improved (p<0.01) the activity of chymotrypsin. Protein content at d 10 was highest (p<0.001) with addition of phytase while general proteolytic activity (GPA) (p<0.02) and lipase activity (p<0.001) were decreased. At d 24, there were improvements in protein content (p<0.01) and lipase (p<0.04) with supplementation of superdose phytase. Addition of superdose phytase decreased in chymotrypsin (p<0.02), trypsin (p<0.01) and GPA (p<0.001). The optimum dose of xylanase decreased the chymotrypsin activity (p = 0.05), while the GPA (p<0.001) was increased with the optimum level of β-glucanase. Superdose phytase supplementation at d 10 improved maltase (p = 0.05), sucrase (p<0.001) and alkaline phosphatase (p<0.001) activities in the jejunum while aminopeptidase activity was highest (p<0.005) with the low level of phytase. Protein content of jejunum mucosa was bigger (p<0.001) in birds fed superdose phytase while maltase activity (p<0.001) at d 24 was reduced by this treatment. Sucrase (p<0.04) and aminopeptidase activities (p<0.001) improved when diets supplemented with low levels of phytase. Tibia bone breaking strength was highest (p<0.04) with addition of low level of superdose phytase or optimum level of β-glucanase. Bone dry matter content decreased (p<0.04) when diets supplemented with phytase.

Conclusion

From the results obtained in this study, supplementation of superdose phytase was the most effective, however, the cost-benefit analysis of the use of such a dose needs to be evaluated.

Heme and Non-heme Iron on Growth Performances, Blood Parameters, Tissue Mineral Concentration, and Intestinal Morphology of Weanling Pigs

This experiment was conducted to evaluate the effects of heme and non-heme iron sources on growth performances, blood parameters, tissue mineral concentration, and intestinal morphology in weanling pigs. At 25 days of age, 32 newly weaned piglets (Duroc × Landrace × Yorkshire; 8.66 ± 0.59 kg) were allocated to one of the following dietary treatments: control group (basal diet with no extra iron addition), FeSO₄ group (basal diet + 100 mg Fe/kg as FeSO₄), Fe-Gly group (basal diet + 100 mg Fe/kg as Fe-Gly), and Heme group (basal diet + 100 mg Fe/kg as Heme). Each treatment had eight replicates and one pig per replicate. The experiment lasted for 28 days. The results showed that compared with basal diet, supplement with 100 mg/kg iron can increase ADG of the piglets, especially in the late experiment period (15~28 days). Heme significantly increased the a* value of longissimus dorsi muscle of piglets when compared with other iron sources (P < 0.05). The iron supplementations had no significant effect on hematological parameters, while Fe-Gly and heme increased pigs' serum iron content on day 28 when compared with FeSO₄ and basal diet (P < 0.05). The liver iron deposition in pigs fed Fe-Gly and heme was also higher than those fed FeSO₄ or basal diet (P < 0.05). Besides, diet supplement with iron significantly increased villus height (P < 0.05) in duodenum and it had tendency to increase villus height and crypt depth ratio in duodenum (P = 0.095). In conclusion, iron supplementation in diets can improve piglet's body iron state and intestinal development, but Fe-Gly and heme exhibited better bioavailability than traditional additive of FeSO₄.

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

The aim of the study was to determine how inorganic and organic forms of zinc affect the concentrations of C-reactive protein (CRP), serum amyloid A (SAA), alpha-1-acid glycoprotein (α-1-AGP), haptoglobin (Hp), and transferrin (TRF) in the blood and liver tissue of 450 1-day-old Ross 308 chicken. Four experimental groups received one the following: inorganic zinc (ZnSO4), a zinc phytase enzyme supplement (ZnSO4-F), organic zinc in combination with glycine (Zn-Gly), or organic zinc supplemented with phytase (Zn-Gly-F). The chicken serum and liver homogenates were assayed using an ELISA kit. The results of the study showed statistically significantly higher serum and liver concentration of SAA in the group of birds that received zinc sulfate in comparison to the group of birds receiving zinc in organic form. A statistically significantly higher serum concentration of CRP and α-1-AGP was also noted in the group receiving zinc sulfate as compared to the Zn-Gly group. Comparison of the serum concentration of TRF between the supplemented groups showed a statistically significant increase in this parameter in the Zn-Gly-F group as compared to the ZSO4-F group. The increase in the serum concentration of Hp in all groups in comparison to the control may indicate stimulation of local immune mechanisms. The results of this study showed an increase in the concentrations of APPs such as AGP and TRF following the administration of zinc glycine chelates, which may demonstrate their effect on metabolic processes in the liver and on immunocompetent cells that regulate the intensity of the immune response.

Effect of elevated dietary inorganic zinc on live performance, carcass yield, and quality of male and female broilers

This study evaluated the effects of elevated dietary inorganic zinc (Zn) on live performance, carcass and parts yield, and carcass and meat quality of broilers. A total of 288 d-old Ross 344 × 708 broilers were distributed among 3 dietary treatments with 12 replicate cages per treatment and raised sex-separate with 8 birds per cage. Birds were fed practical diets supplemented with either 0, 120, or 240 mg Zn/kg diet. Feed intake and body weight (BW) were measured and feed conversion ratio (FCR) was calculated. At 42 d, 3 birds per cage were processed to assess carcass and meat quality. Male BW at 42 d was increased (P ≤ 0.05) by 120 mg Zn/kg. The FCR to 42 d was also improved (P ≤ 0.05) for males supplemented with 120 mg Zn/kg as compared to 240 mg Zn/kg with the 0 mg Zn/kg diet intermediate. Dietary Zn had no effect on BW or FCR of females. Dietary Zn had no effect on carcass weight and parts yield but absolute weights of male, but not female, total breast and tenders were increased by 240 mg Zn/kg relative to 0 mg Zn/kg with 120 mg Zn/kg intermediate. Breast fillets cook yield and tenderness as well as color were not influenced by Zn in either sex. Supplementing 120 mg Zn/kg resulted in increased Zn in male breast muscle (P ≤ 0.01) whereas 240 mg Zn/kg reduced Zn in breast muscle of females. The 240 mg Zn/kg diet increased Zn in femurs (P ≤ 0.05) of males relative to the other diets. For females, Zn concentration in femurs was increased (P ≤ 0.05) by 240 mg Zn/kg relative to 120 mg Zn/kg with the non-supplemented birds intermediate.

Subsequent somatic axis and bone tissue metabolism responses to a low-zinc diet with or without phytase inclusion in broiler chickens

Zinc is required for normal bone development and cartilage formation. The purpose of this study was to assess the effect of with adding organic Zn (alone or phytase inclusion) at the reduced dose to growing male Ross 308 chickens on somatic axis and bone tissue metabolism. 200 one-day old broilers were divided into the negative control group fed diet without Zn or phytase inclusion, positive control group receiving Zn in the 100% of daily recommended dose from ZnO, and two experimental groups fed diet introduced Zn in 25% of daily recommendation as a glycine chelate (Zn-Gly) with or without phytase inclusion (500 FTU·kg-1). Supplemental organic Zn increased bone Zn and Mg content, serum IGF-1, growth hormone and leptin concentration. Additional phytase inclusion increased body weight gain, blood plasma Ca, Fe, Zn and osteocalcin concentration and tibia ash percentage when compared to the Zn-deprived control. Bone geometry, yield and ultimate strengths were enhanced in both organic Zn supplemented groups, and the overall mechanical strength parameters of bone were better in these groups than in the positive control group supplemented with standard dose of inorganic Zn. Also marked improvements in the thickness of articular and the growth plate cartilages as well as real bone volume and thickness of metaphyseal trabeculae were achieved in all broilers fed Zn-supplemented diet irrespective of phytase inclusion, however, the highest cancellous bone mass and the best trabecular structure were noted after ZnO supplementation. In concludion, although dietary organic Zn given to growing broilers in 25% of daily recommended dose improved general bone properties and mechanical strength, the obtained results do not allow to unambiguously state that organic Zn supplementation at this level, even after phytase inclusion, is sufficient for proper bone development.

Evaluation of trace mineral source and preharvest deletion of trace minerals from finishing diets on tissue mineral status in pigs

Objective

An experiment was conducted to evaluate dietary supplemental trace mineral source and deletion on mineral content in tissues.

Methods

Weanling crossbred pigs (n = 144; 72 barrows and 72 gilts; body weight [BW] = 7.4±1.05 kg) were used. A basal diet was prepared, and trace mineral premix containing either inorganic (ITM) or organic (OTM) trace minerals (Cu, Fe, Mn, and Zn) was added to the basal diet. Pigs were blocked by sex and BW and randomly allotted to 24 pens for a total of 6 pigs per pen, and fed a diet containing either ITM or OTM supplemented at the 1998 NRC requirement estimates for each of 5 BW phases (Phase I to V) from 7 to 120 kg. The trace mineral supplementation was deleted for 6, 4, 2, and 0 wk of Phase V; regarding nutrient adequacy during this phase, the indigenous dietary Fe and Mn was sufficient, Cu was marginal and Zn was deficient.

Results

At the end of Phase IV, Mn content (mg/kg on the dry matter basis) was greater (p<0.05) in heart (0.77 vs 0.68), kidney (6.32 vs 5.87), liver (9.46 vs 8.30), and longissimus dorsi (LD; 0.30 vs 0.23) of pigs fed OTM. The pigs fed OTM were greater (p<0.05) in LD Cu (2.12 vs 1.89) and Fe (21.75 vs 19.40) and metacarpal bone Zn (141.86 vs 130.05). At the end of Phase V, increased length of deletion period (from 0 to 6 wk) resulted in a decrease (linear, p<0.01) in liver Zn (196.5 to 121.8), metacarpal bone Zn (146.6 to 86.2) and an increase (linear, p<0.01) in heart Mn (0.70 to 1.08), liver Mn (7.74 to 12.96), and kidney Mn (5.58 to 7.56). The only mineral source by deletion period interaction (p<0.05) was observed in LD Zn.

Conclusion

The results demonstrated differential effects of mineral deletion on tissue mineral content depending on both mineral assessed and source of the mineral.

Effects of feed supplementation with glycine chelate and iron sulfate on selected parameters of cell-mediated immune response in broiler chickens

Because little is known about the impact of chelated (Fe-Gly, Fe-Gly+F) and inorganic (FeSO4, FeSO4+F) iron products on immune response parameters in broiler chickens, the objective of the study was to determine the effects of inorganic and organic forms of iron on selected parameters of the cell-mediated immune response in broiler chickens by assessing the percentage of CD3(+)CD4(+), CD3(+)CD8(+), CD25(+), and MHC Class II lymphocytes, as well as the CD4(+)/CD8(+) ratio and IL-2 concentration in the peripheral blood. The experiments were conducted using 50day-old Ross 308 roosters. The test material was peripheral blood. Flow cytometry was used to determine selected cell-mediated immune response parameters. The results obtained indicate that the use of iron chelates in the diet of broiler chickens may stimulate cellular defense mechanisms. As a result of the experiment an increase was observed in the percentage of Th1, mainly T CD4(+) and T CD8(+). It was also noted that application of chelated iron can increase production of T CD8(+) cytotoxic cells and IL-2, which promotes the body's natural response to developing inflammation. There were no changes in T CD4(+), T CD8(+), T CD25(+) or MHC II lymphocyte subpopulations in the chickens following application of the inorganic form of iron.

Comparison of 3 phytases on energy utilization of a nutritionally marginal wheat-soybean meal broiler diet

The net energy (NE) value may be a better measure than apparent metabolizable energy (ME) of the effect of supplemental phytase on energy utilization in broilers. The present study was conducted to assess the impact of 3 microbial phytases supplemented at an unconventionally high level (1,000 FTU/kg feed) on performance and NE of broilers using the indirect calorimetric method (IC). Four treatments included: 1) Control, formulated to be deficient in ME (12.35 MJ/kg in the starter diet; 12.56 MJ/kg in the grower diet), calcium (0.72% in the starter diet; 0.60% in the grower diet), and available phosphorus (0.25% in the starter diet; 0.20% in the grower diet); 2) control + intrinsically thermostable phytase A; 3) control + intrinsically thermostable phytase B; and 4) control + coated phytase C. A completely randomized design was employed. A total of 384 male broiler chicks were used, and each treatment had 6 replicates with 16 birds per replicate. The birds were reared until d 21 in floor pens with hardwood shavings. Thirty-two birds (8 birds per treatment) were randomly selected to determine heat production and NE (from 25-28 d) following a 3-d acclimatization in the respiratory chambers. Performance results at d 21 showed that supplementation with either of the 3 phytases improved body weight (P < 0.001) and feed intake (P < 0.05), and increased the relative weights of tibia ash (P < 0.05) and toe ash (P < 0.01). Phytases A and B increased the NE value of the diet (P < 0.05). It may be concluded that the negative effects imposed by calcium and available phosphorus down-specification can be compensated by phytase supplementation in general, and intrinsically thermostable phytases improve the ME and NE value. However, phytase did not reduce heat production, heat increment, or increase NE:ME in birds.

Effects of iron glycine chelate on growth, tissue mineral concentrations, fecal mineral excretion, and liver antioxidant enzyme activities in broilers

The study was conducted to determine the effects of iron glycine chelate (Fe-Gly) on growth, tissue mineral concentrations, fecal mineral excretion, and liver antioxidant enzyme activities in broilers. A total of 360 1-day-old commercial broilers (Ross × Ross) were randomly allotted to six dietary treatments with six replications of ten chicks per replicate. Broilers were fed a control diet with no Fe supplementation, while five other treatments consisted of 40, 80, 120, and 160 mg Fe/kg diets from Fe-Gly, and 160 mg Fe/kg from ferrous sulfate, respectively. After a 42-day feeding trial, the results showed that 120 and 160 mg Fe/kg as Fe-Gly improved the average daily gain (P < 0.05) and average daily feed intake (P < 0.05) of broilers (4-6 weeks). Addition with 120 and 160 mg Fe/kg from Fe-Gly and 160 mg Fe/kg from FeSO(4) increased Fe concentration in serum (P < 0.05), liver (P < 0.05), breast muscle (P < 0.05), tibia (P < 0.05), and feces (P < 0.01) at 21 and 42 days. There were linear responses to the addition of Fe-Gly from 0 to 160 mg/kg Fe on Fe concentration in serum (21 days, P = 0.005; 42 days, P = 0.001), liver (P = 0.001), breast muscle (P = 0.001), tibia (P = 0.001), and feces (21 days, P = 0.011; 42 days, P = 0.032). Liver Cu/Zn superoxide dismutase activities of chicks were increased by the addition of 80, 120, and 160 mg Fe/kg as Fe-Gly to diets at 42 days. There were no differences in liver catalase activities of chicks among the treatments (P > 0.05). This study indicates that addition with Fe-Gly could improve growth performance and iron tissue storage and improves the antioxidant status of broiler chickens.

Effects of organic zinc and phytase supplementation in a maize-soybean meal diet on the performance and tissue zinc content of broiler chicks

1. The purpose of this study was to investigate the effects of Bioplex Zn (a chelated zinc proteinate) and phytase supplementation in a maize-soybean meal diet on the performance and tissue zinc (Zn) content of broiler chicks. Treatment structure consisted of a 2 x 6 factorial arrangement with two inclusions of phytase (0 or 500 PU/kg) and 6 of Bioplex Zn providing 0, 2, 4, 8, 16 and 32 mg Zn/kg diet. A total of 864 chicks were randomly assigned to each of 12 dietary treatments with 6 replicate cages of 12 chicks. 2. Dietary inclusion of phytase increased feed intake, weight gain, plasma Zn content, tibia Zn content, tibia and ash weight. 3. Dietary supplementation of Bioplex Zn linearly increased feed intake, weight gain, gain to feed ratio, plasma Zn concentration, liver Zn concentration, tibia Zn content, tibia and ash weight. 4. An interactive effect of phytase and Bioplex Zn on feed intake, weight gain, tibia Zn concentration and tibia ash weight was found. 5. One slope, straight broken-line analysis of weight gain regressed on the supplemental Zn level provided as Bioplex Zn indicated that 12 mg/kg supplemental Zn without phytase and 7.4 mg/kg supplemental Zn with phytase were required for the optimal weight gain of chicks.