Determination of dietary iron requirements by full expression of iron-containing cytochrome c oxidase in the heart of broilers from 22 to 42 d of age

Low protein diet influences mineral absorption and utilization in medium-growing yellow-feathered broilers from 1 to 30 days of age

Reduced-protein diet can save protein ingredients and reduce nitrogen (N) losses. However, the effect of low protein diet on the mineral uptake and utilization in broilers needs to be explored. The aim of this study was to investigate the effect of low-protein diet on the growth performance, N deposition, mineral contents in serum, tissues and excreta, and the activities and gene expression of related enzymes in tissues of medium-growing yellow-feathered broilers, so as to elucidate the relationship between dietary protein level and the absorption and utilization of minerals in broilers. A total of 72 1-d-old Spotted-Brown male broilers were randomly allotted to 1 of 2 treatments with 6 replicate cages of 6 birds per cage for each treatment. The dietary crude protein (CP) levels for the two treatments were 21 % (the control treatment) and 19 % (low protein treatment), respectively. The experimental period was 30 d. The results showed that no differences (P > 0.05) were detected in average daily gain, average daily feed intake and feed: gain ratio of broilers during 1 to 30 d between the two treatments. However, low protein intake increased (P < 0.05) N retention rate, serum P, Cu and Mn, and excreta Cu, Mn and Zn, and decreased (P < 0.05) liver P and excreta P. In addition, birds fed low protein diet had higher (P < 0.05) manganese superoxide dismutase, and total superoxide dismutase activities in liver, and total antioxidant capacity and malondialdehyde content in heart, and lower (P < 0.05) copper-zinc superoxide dismutase (CuZnSOD) and succinate dehydrogenase activities in liver and CuZnSOD mRNA level in heart. In conclusion, the reduction of dietary CP content from 21 % to 19 % improved N retention, the absorption of P, Cu and Mn, as well as the antioxidant ability of liver and heart, and influenced metabolic utilization of P, Cu, Zn, Fe and Mn in medium-growing yellow-feathered broilers from 1 to 30 d of age.

Dietary contribution of iron from limestone and dicalcium phosphate for broiler chickens

Iron is routinely supplemented in broiler feeds aiming to prevent dietary deficiencies. Limestone and phosphates are very rich in Fe; however, its contribution from these sources have not been thoroughly investigated with chickens. The present research was conducted to evaluate live performance and blood parameters of broilers when using limestone and dicalcium phosphate as sources of Fe. A total of 576 one-day-old male Cobb x Cobb 500 were allocated into a total of 72 battery cages, 6 treatments with 12 replication cages of 8 chicks at placement. Chicks were fed diets formulated with corn, soybean meal (SBM) with laboratory grade calcium carbonate and phosphoric acid (having traces of Fe). All chicks were fed a common prestarter without Fe supplementation (analyzed total 58.2 ± 2.4 mg/kg Fe) from placement to 7 d. Allocation of birds to dietary treatments was completely randomized on day 8. Treatments had increasing Fe derived from commercial limestone and dicalcium phosphate (analyzed Fe 7,218 and 4,783 mg/kg, respectively) progressively replacing calcium carbonate and phosphoric acid to provide graded increases in total Fe (analyzed Fe in the feeds were 57.6 ± 2.1, 92.0 ± 2.3, 124.1 ± 2.7, 159.3 ± 3.1, 187.2 ± 3.2, 223.7 ± 3.6 mg/kg, respectively). There were no effects of dietary Fe on live performance, hematocrit, and hemoglobin the end of the study on day 28 (P > 0.05). Increasing dietary Fe from commercial limestone and dicalcium phosphate led to a linear reduction in the percent ileal digestible Fe. However, linear increments in Fe retention, serum ferritin and liver Fe occurred when compared to feeds without Fe derived from limestone and phosphate dicalcium. It is concluded that Fe from limestone and dicalcium phosphate can be partially utilized by broiler chickens. It was estimated that the Fe retained from limestone and dicalcium phosphate is of 1.9%. Broilers fed corn-soy feeds (58.2 mg/kg Fe) do not require supplemental Fe.

Dietary copper requirement of broilers fed a corn-soybean meal diet during 22-42 d of age

This research was to assess the dietary copper (Cu) requirement of broiler chickens fed a practical corn-soybean meal diet during 22-42 d of age. A total of 288 numbered Arbor Acres male broilers at 22 d of age were randomly allotted 6 treatments with 8 replicate cages (6 broilers per cage) per treatment. Broilers were fed a Cu-unsupplemented corn-soybean meal basal diet (control, containing 7.36 mg Cu/kg) or the basal diet added with 3, 6, 9, 12, or 15 mg Cu/kg from CuSO4·5H2O for 21 d. Quadratic, asymptotic and broken-line models were fitted and the best fitted models were selected to determine dietary Cu requirements. The results revealed that the contents of Cu in serum and liver, mRNA expression levels of Cu- and zinc-containing superoxide dismutase (CuZnSOD) in liver and monoamine oxidase b (MAO B) in heart, as well as protein expression level of CuZnSOD in liver were affected (P < 0.05) by supplemental Cu levels, and the above indices varied linearly and quadratically (P < 0.05) with increasing Cu levels. Dietary Cu requirements assessed according to the best fitted broken-line models (P < 0.05) of the above indexes were 10.45-13.81 mg/kg. It was concluded that mRNA expression levels of CuZnSOD in liver and MAO B in heart, as well as liver CuZnSOD protein expression level were new specific sensitive biomarkers for estimating dietary Cu requirements, and the dietary Cu requirement was recommended to be 14 mg/kg to support Cu metabolic needs related to key Cu-containing enzymes in broilers fed the corn-soybean meal diet during 22-42 d of age, which was higher than the dietary Cu requirement (8 mg/kg) for broilers at the corresponding stage suggested by the Chinese Feeding Standard of Chicken.

The chemical characteristics of different sodium iron ethylenediaminetetraacetate sources and their relative bioavailabilities for broilers fed with a conventional corn-soybean meal diet

BACKGROUND

Our previous studies demonstrated that divalent organic iron (Fe) proteinate sources with higher complexation or chelation strengths as expressed by the greater quotient of formation (Qf) values displayed higher Fe bioavailabilities for broilers. Sodium iron ethylenediaminetetraacetate (NaFeEDTA) is a trivalent organic Fe source with the strongest chelating ligand EDTA. However, the bioavailability of Fe when administered as NaFeEDTA in broilers and other agricultural animals remains untested. Herein, the chemical characteristics of 12 NaFeEDTA products were determined. Of these, one feed grade NaFeEDTA (Qf = 2.07 × 108), one food grade NaFeEDTA (Qf = 3.31 × 108), and one Fe proteinate with an extremely strong chelation strength (Fe-Prot ES, Qf value = 8,590) were selected. Their bioavailabilities relative to Fe sulfate (FeSO4·7H2O) for broilers fed with a conventional corn-soybean meal diet were evaluated during d 1 to 21 by investigating the effects of the above Fe sources and added Fe levels on the growth performance, hematological indices, Fe contents, activities and gene expressions of Fe-containing enzymes in various tissues of broilers.

RESULTS

NaFeEDTA sources varied greatly in their chemical characteristics. Plasma Fe concentration (PI), transferrin saturation (TS), liver Fe content, succinate dehydrogenase (SDH) activities in liver, heart, and kidney, catalase (CAT) activity in liver, and SDH mRNA expressions in liver and kidney increased linearly (P < 0.05) with increasing levels of Fe supplementation. However, differences among Fe sources were detected (P < 0.05) only for PI, liver Fe content, CAT activity in liver, SDH activities in heart and kidney, and SDH mRNA expressions in liver and kidney. Based on slope ratios from multiple linear regressions of the above indices on daily dietary analyzed Fe intake, the average bioavailabilities of Fe-Prot ES, feed grade NaFeEDTA, and food grade NaFeEDTA relative to the inorganic FeSO4·7H2O (100%) for broilers were 139%, 155%, and 166%, respectively.

CONCLUSIONS

The bioavailabilities of organic Fe sources relative to FeSO4·7H2O were closely related to their Qf values, and NaFeEDTA sources with higher Qf values showed higher Fe bioavailabilities for broilers fed with a conventional corn-soybean meal diet.

Iron requirements of broiler chickens as affected by supplemental phytase

Iron is routinely supplemented in broiler feeds intending to prevent dietary deficiencies. The present research was conducted with the objective of assessing Fe requirements of broilers when fed supplemental phytase. A total of 1,280 1-d-old male Cobb × Cobb 500 were distributed in a 2 × 5 factorial arrangement (phytase-supplemented feeds × 5 graded increases of supplemental Fe) in 80 battery cages, eight replications of eight chicks each. The trial was replicated once. Chicks were fed a Fe-deficient diet without phytase (Fe analyzed at 31.30 ± 3.79 mg/kg) from placement to 7 d and then randomly distributed into battery cages with corresponding dieting treatments with or without phytase and graded increases of supplemental Fe. Feeds were formulated with corn and soybean meal (SBM), laboratory-grade calcium carbonate, and phosphoric acid; therefore, the vast majority of dietary Fe originated from corn and SBM (analyzed diet had 53.3 ± 1.41 mg/kg Fe). Phytase was added in excess to the producer recommendation of 1,000 FYT (4,452 ± 487 FYT/kg analyzed) such that phytate degradation was expected to be maximized. Supplemental Fe was from laboratory-grade ferrous sulfate heptahydrate (FeSO47H2O) which was increasingly added to the feeds (analyzed Fe in the supplemented feeds were: 53.3 ± 1.41, 65.5 ± 0.59, 77.2 ± 1.97, 87.6 ± 1.72, 97.7 ± 1.33 mg/kg). There were no interactions between phytase and dietary Fe for any response throughout the study (P > 0.05). Supplementing phytase had no effects on Fe intake or Fe excretion, as well as on hematocrit (Ht), hemoglobin (Hb), ferritin, Fe contents in the liver or thigh muscle color (P > 0.05). However, phytase-supplemented feeds produced better live performance as well as higher ileal digestible energy and Fe digestibility (P < 0.05). No effects were found for dietary Fe in live performance at day 28 (P > 0.05). On the other hand, increasing dietary Fe led to linear increases in Fe retention and excretion, Fe contents in livers, as well as Ht and Hb at 14 d (P < 0.05). Quadratic responses (P < 0.05) were observed for Hb at 21 d, serum ferritin on days 14, 21, and 28 (maximum responses were 83.3, 104.0, 91.9, and 88.3 mg/kg Fe, respectively). In conclusion, supplementing Fe adding to a total of 97.7 mg/kg dietary Fe did not affect live performance traits. However, the average of Fe-related blood parameters was maximized at 91.9 mg/kg dietary Fe. Supplementing phytase provided a significant increase in Fe digestibility.

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.

Effects of Dietary Supplementation with Iron in Breeding Pigeons on the Blood Iron Status, Tissue Iron Content, and Full Expression of Iron-Containing Enzymes of Squabs

This study was aimed at investigating the effects of diet iron levels on the blood iron status, tissue iron content, mRNA levels, and the activity of iron-containing enzymes in different tissues of squabs. A total of 120 pairs of healthy Silver Feather King parental pigeons with similar average body weight and egg production were randomly divided into 5 groups with 8 replicates and 3 pairs of pigeons per replicate. The five groups of breeding pigeons were fed an iron-unsupplemented basal diet and basal diet supplemented with 75, 150, 300, and 600 mg iron/kg, respectively. The diets were fed in the form of granular feed based on corn, soybean meal, wheat, and sorghum. A broken line model was used for regression analysis. The results showed that plasma iron (PI), serum ferritin, iron contents in crop milk and liver, liver catalase (CAT) activity, and heart succinate dehydrogenase (SDH) activity were affected by iron levels (P < 0.05). And PI, serum ferritin, iron content in crop milk, and heart SDH activity increased quadratically (P < 0.05), but the iron content and CAT activity in the liver decreased quadratically (P < 0.005) as dietary iron level increased. According to the broken-line model of serum ferritin fitting (P < 0.002), the optimal dietary iron level of breeding pigeons was estimated to be 193 mg/kg. In conclusion, serum ferritin is a sensitive index to evaluate the iron requirement of the breeding pigeon with two squabs, and the recommended iron supplemental level is 193 mg/kg.

Protective Effects of Resveratrol on Adolescent Social Isolation-Induced Anxiety-Like Behaviors via Modulating Nucleus Accumbens Spine Plasticity and Mitochondrial Function in Female Rats

Social isolation (SI) is a major risk factor for mood disorders in adolescents. The nucleus accumbens (NAc) is an important reward center implicated in psychiatric disorders. Resveratrol (RSV) is one of the most effective natural polyphenols with anti-anxiety and depression effects. However, little is known about the therapeutic effects and mechanisms of RSV on behavioral abnormality of adolescent social stress. Therefore, this study aimed to investigate the underlying mechanism of RSV on the amelioration of SI-induced behavioral abnormality. We found that SI induced anxiety-like behavior and social dysfunction in isolated female rats. Moreover, SI reduced mitochondrial number and ATP levels and increased thin spine density in the NAc. RNA sequencing results showed that SI changed the transcription pattern in the NAc, including 519 upregulated genes and 610 downregulated genes, especially those related to mitochondrial function. Importantly, RSV ameliorated behavioral and spine abnormalities induced by SI and increased NAc ATP levels and mitochondria number. Furthermore, RSV increased the activity of cytochrome C oxidase (COX) and upregulated mRNA levels of Cox5a, Cox6a1 and Cox7c. These results demonstrate that the modulation of spine plasticity and mitochondrial function in the NAc by RSV has a therapeutic effect on mood disorders induced by social isolation.

High Dietary Organic Iron Supplementation Decreases Growth Performance and Induces Oxidative Stress in Broilers

Although Iron (Fe) is an essential nutrient that plays a vital role in respiratory processes, excessive Fe in the diet can affect the health of broilers. We investigated the effects of diet supplemented with high levels of iron chelates with lysine and glutamic acid (Fe−LG) on the growth performance, serum biochemical parameters, antioxidant status, and duodenal mRNA expression of Fe transporters in broilers. A total of 800 1-day-old male Arbor Acres broilers were assigned to 5 groups, with 8 replicates each. Broilers were fed a corn−soybean meal basal diet or basal diets supplemented with 40, 80, 400, or 800 mg Fe/kg as Fe−LG for 6 weeks. The body weight (BW) was increased in the 80 mg Fe/kg treatment group, but decreased in the 800 mg Fe/kg treatment group on day 21. During days 1−21, compared with the control group, the supplementation of the 80 mg Fe/kg increased the average daily gain (ADG) and average daily feed intake (ADFI); however, the supplementation of the 800 mg Fe/kg group decreased the ADG and increased the FCR in broilers (p < 0.05). The heart, liver, spleen, and kidney indices were reduced in the 800 mg Fe/kg treatment group (p < 0.05). The supplementation of the 800 mg Fe/kg group increased the serum aspartate aminotransferase activity and the levels of creatinine and urea nitrogen on day 42 (p < 0.05). The broilers had considerably low liver total superoxide dismutase activity and total antioxidant capacity in the 800 mg Fe/kg treatment group (p < 0.05). Serum and liver Fe concentrations were elevated in the 400 and 800 mg Fe/kg treatment groups, but were not affected in the 40 and 80 mg Fe/kg treatment groups. The duodenal Fe transporters divalent metal transporter 1 (DMT1) and ferroportin 1 (FPN1) were downregulated in the Fe−LG treatment groups (p < 0.05). We conclude that a high dietary supplement of 800 mg Fe/kg in broilers leads to detrimental health effects, causing kidney function injury and liver oxidative stress.

Research Note: Metabolic utilization of iron from different iron sources in primary cultured hepatocytes of broiler embryos

The present study was carried out to evaluate the effects of iron (Fe) sources and levels on the Fe concentration and expressions of iron-containing enzymes or protein in primary cultured hepatocytes of broiler embryos. The hepatocytes were incubated with 0, 0.25 and 0.50 mmol/L added Fe from either Fe sulfate, or 1 of 3 organic Fe chelates with weak (Fe-Met W), moderate (Fe-Pro M), or extremely strong (Fe-Pro ES) chelation strengths for 24 h. The results showed that all supplemental Fe treatments had higher (P < 0.05) Fe concentration, succinate dehydrogenase (SDH), CAT and ferritin heavy chain 1 (FTH1) mRNA levels than those in the control group. The hepatocytes incubated with Fe-Prot ES had lower (P < 0.009) Fe concentration than those incubated with Fe sulfate, Fe-Met W or Fe-Prot M. The SDH mRNA level was lower (P < 0.05) in Fe sulfate and Fe-Prot ES groups than in Fe-Prot M group. In conclusion, the Fe from Fe-Prot ES was less utilizable than Fe from Fe sulfate, Fe-Met W or Fe-Pro M in primary cultured hepatocytes of broiler embryos.

Metabolic utilization of intravenously injected iron from different iron sources in target tissues of broiler chickens

No information is available regarding the utilization of iron (Fe) from different Fe sources at a target tissue level. To detect differences in Fe metabolic utilization among Fe sources, the effect of intravenously injected Fe on growth performance, hematological indices, tissue Fe concentrations and Fe-containing enzyme activities and gene expressions of Fe-containing enzymes or protein in broilers was investigated. On d 22 post-hatching, a total of 432 male chickens were randomly allotted to 1 of 9 treatments in a completely randomized design. Chickens were injected with either a 0.9% (wt/vol) NaCl solution (control) or a 0.9% NaCl solution supplemented with Fe sulphate or 1 of 3 organic Fe sources. The 3 organic Fe sources were Fe chelates with weak (Fe-MetW), moderate (Fe-ProtM) or extremely strong (Fe-ProtES) chelation strength. The 2 Fe dosages were calculated according to the Fe absorbabilities of 10% and 20% every 2 d for a duration of 20 d. Iron injection did not affect (P > 0.05) ADFI, ADG or FCR during either 1 to 10 d or 11 to 20 d after injections. Hematocrit and Fe concentrations in the liver and kidney on d 10 after Fe injections, and Fe concentrations in the liver or pancreas and ferritin heavy-chain (FTH1) protein expression level in the liver or spleen on d 20 after Fe injections increased (P ≤ 0.05) as injected Fe dosages increased. When the injected Fe level was high at 20% Fe absorbability, the chickens injected with Fe-ProtES had lower (P < 0.001) liver or kidney Fe concentrations and spleen FTH1 protein levels than those injected with Fe-MetW or Fe-ProtM on d 20 after injections. And they had lower (P < 0.05) liver cytochrome C oxidase mRNA levels on d 20 after injections than those injected with Fe-MetW or Fe sulphate. The results from this study indicate that intravenously injected Fe from Fe-ProtES was the least utilizable and functioned in the sensitive target tissue less effectively than Fe from Fe sulfate, Fe-MetW or Fe-ProtM.

Determination of dietary copper requirement by the monoamine oxidase activity in kidney of broilers from 1 to 21 d of age

The current dietary copper (Cu) requirement (8 mg/kg) of broilers is mainly based on growth, hemoglobin concentration, or hematocrit, which might not be the most sensitive indices to evaluate dietary Cu requirements of broilers. The present study was carried out to estimate dietary Cu requirements of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age using biochemical or molecular biomarkers. A total of 384 1-d-old Arbor Acres male broilers were randomly allocated to 1 of 6 treatments with 8 replicates and fed a Cu-unsupplemented corn-soybean meal basal diet containing 5.17 mg Cu/kg by analysis and the basal diet supplemented with 3, 6, 9, 12 or 15 mg Cu/kg as CuSO₄⋅5H₂O for 21 d. Regression analysis was performed to estimate the optimal dietary Cu level using the broken-line model. Dietary supplemental Cu level affected (P < 0.05) Cu contents in serum and liver and kidney monoamine oxidase (MAO) activity, but had no effects (P > 0.05) on the growth performance, Cu contents in heart, kidney, pancreas and spleen, Cu- and zinc-containing superoxide dismutase (CuZnSOD) activity and ceruloplasmin content in serum, CuZnSOD and cytochrome c oxidase (COX) activities and ceruloplasmin, CuZnSOD, MAO A, MAO B, COX4I1 and COX1 mRNA and protein expressions in the above tissues of broilers. As dietary supplemental Cu levels increased, Cu contents in serum and liver increased linearly (P < 0.05), but kidney MAO activity decreased linearly and quadratically (P < 0.05). The estimated dietary Cu requirement based on the fitted broken-line model (P = 0.035) of kidney MAO activity was 11.30 mg/kg. In conclusion, kidney MAO activity is a new and sensitive criterion to evaluate the dietary Cu requirement of broilers, and the dietary Cu requirement was 11.30 mg/kg for broilers fed the conventional corn-soybean meal diet from 1 to 21 d of age, which is higher than the current National Research Council (NRC) Cu requirement (8 mg/kg) of broilers.

Effects of Dietary Iron Concentration on Manganese Utilization in Broilers Fed with Manganese-Lysine Chelate-Supplemented Diet

Dietary iron (Fe) influences manganese (Mn) utilization in chickens fed with inorganic Mn-supplemented diet. This study aimed to determine if dietary Fe levels affect Mn utilization in broilers fed with organic Mn-supplemented diet. Nine hundred 8-day-old broilers were randomly assigned to 1 of 6 treatments in a 3 (Fe level) × 2 (Mn source) factorial arrangement after feeding Mn- and Fe-unsupplemented diets for 7 days. The broilers were fed the basal diets (approximately 28 mg Mn/kg and 60 mg Fe/kg) supplemented with 0, 80, or 160 mg/kg Fe (L-Fe, M-Fe, or H-Fe), and 100 mg/kg Mn from Mn sulfate (MnSO₄) or manganese-lysine chelate (MnLys) for 35 days. The H-Fe diet decreased (P < 0.05) body weight gain and feed intake as compared with L-Fe and M-Fe diets regardless of dietary Mn sources. Dietary Fe levels did not influence (P > 0.10) serum Mn concentration in MnLys-treated broilers, but serum Mn concentration decreased (P < 0.05) with dietary Fe increasing in MnSO₄-treated broilers. The Mn concentration in the duodenum and tibia decreased (P < 0.05) with increasing dietary Fe levels regardless of dietary Mn sources, and MnLys increased (P < 0.04) these indices as compared with MnSO₄. Dietary Fe levels did not significantly influence (P > 0.11) Mn concentration and activity and mRNA abundance of manganese-containing superoxide dismutase (MnSOD) in the heart of MnLys-treaded broilers, but the H-Fe diet decreased (P < 0.05) these indices in MnSO₄-treated broilers as compared with M-Fe and L-Fe diets. The L-Fe diet increased (P < 0.001) duodenal divalent metal transporter 1 mRNA abundance when compared with the M-Fe and H-Fe diets on day 42, regardless of dietary Mn sources. The M-Fe and H-Fe diets decreased (P < 0.001) duodenal ferroportin 1 (FPN1) mRNA level when compared with the L-Fe diet in MnSO₄-treated broilers, while dietary Fe levels did not significantly influence (P > 0.40) duodenal FPN1 mRNA abundance in MnLys-treated broilers. These results indicated dietary Fe levels decreased Mn utilization in MnSO₄-treated broilers, but did not influence Mn utilization in MnLys-treated broilers evaluated by Mn concentrations in the serum and heart, and the activity and mRNA expression of heart MnSOD.

Optimal dietary copper requirements and relative bioavailability for weanling pigs fed either copper proteinate or tribasic copper chloride

Background

The objective of this study was to determine the effects of supplementing Cu on growth performance, Cu metabolism and Cu-related enzyme activities of weanling pigs fed diets with two different Cu sources, and to estimate optimal Cu requirements and relative bioavailability from these two sources for pigs.

Methods

Weanling pigs were allocated to 14 treatments arranged factorially, including 6 added Cu levels (5, 10, 20, 40, 80, 160 mg/kg), and 2 mineral sources (tribasic Cu chloride, TBCC and copper proteinate, CuPro), as well as one negative control (0 mg/kg added Cu level) and one maximum allowed level treatment (200 mg/kg TBCC) for the entire 38-d experiment. Growth performance, mineral status and enzyme activities were measured at the end of this study.

Results

Increasing levels of Cu showed linear and quadratic responses (P < 0.01) for final BW, ADG and FCR regardless of the sources. Supplementation with TBCC (> 80 mg/kg) and CuPro (> 20 mg/kg) significantly decreased (P < 0.05) diarrhea incidence of weanling pigs. There were linear and quadratic increases (P < 0.01) in bile, hepatic, and intestinal Cu concentrations, fecal Cu contents, and plasma enzyme activities (alkaline phosphatase, ceruloplasmin, Cu, Zn-Superoxide dismutase (Cu/Zn SOD), and glutathione peroxidase), whereas plasma malondialdehyde decreased (P < 0.01) linearly and quadratically as dietary Cu level increased. Similarly, pigs fed CuPro absorbed and retained more Cu and excreted less Cu than those fed TBCC when supplemented 80 mg/kg and above. Optimal dietary Cu requirements for pigs from 28 to 66 d of age estimated based on fitted broken-line models (P < 0.05) of bile Cu, plasma Cu/Zn SOD and growth performance were 93-140 mg/kg from TBCC, and 63-98 mg/kg from CuPro accordingly. According to slope ratios from multiple linear regression, the bioavailability value of CuPro relative to TBCC (100%) was 156-263% (P < 0.01).

Conclusion

The findings indicated that Cu recommendation from current NRC (5-6 mg/kg) was not sufficient to meet the high requirement of weanling pigs. Cu from CuPro was significantly more bioavailable to weanling pigs than TBCC in stimulating growth and enzyme activities, decreasing diarrhea frequency and fecal Cu contents to the environment.

Effects of Dietary Iron on Manganese Utilization in Broilers Fed with Corn-Soybean Meal Diet

To investigate the effects of dietary iron (Fe) levels on manganese (Mn) utilization, 900 8-day-old broilers were randomly assigned to 1 of 6 treatments in a 3 (Fe level) × 2 (Mn level) factorial arrangement after feeding Mn- and Fe-unsupplemented diet for 7 days. The broilers were then fed with basal corn-soybean meal diets (approximately 28 mg Mn/kg and 60 mg Fe/kg) added with 0, 80, or 160 mg/kg Fe (L-Fe, M-Fe, or H-Fe), and 0 or 100 mg/kg Mn for 35 days. Body weight gain was lower for H-Fe broilers than that for L-Fe and M-Fe broilers. On day 42, H-Fe broilers had lower serum Mn concentration as compared with L-Fe and M-Fe broilers, and tibia Mn concentration decreased as dietary Fe increased. In Mn-supplemented broilers, liver Mn was lower in L-Fe and H-Fe treatments than that in M-Fe treatment. H-Fe treatment decreased Mn concentration and manganese-containing superoxide dismutase (MnSOD) activity in the heart when compared with L-Fe and M-Fe treatments. Dietary Fe did not significantly influence Mn concentrations in the liver and heart, and heart MnSOD activity in Mn-unsupplemented broilers. In the duodenum, L-Fe treatment decreased divalent metal transporter 1 (DMT1) mRNA abundance when compared with M-Fe and H-Fe treatments, and ferroportin 1 (FPN1) mRNA level was higher in M-Fe treatment than that in L-Fe and H-Fe treatments. These results suggested H-Fe diet decreased Mn status in broilers evaluated by Mn concentrations in serum and heart, and heart MnSOD activity. Dietary Fe influenced Mn absorption possibly through effects on duodenal DMT1 and FPN1 expression.

Nicotianamine-chelated iron positively affects iron status, intestinal morphology and microbial populations in vivo (Gallus gallus)

Wheat flour iron (Fe) fortification is mandatory in 75 countries worldwide yet many Fe fortificants, such as Fe-ethylenediaminetetraacetate (EDTA), result in unwanted sensory properties and/or gastrointestinal dysfunction and dysbiosis. Nicotianamine (NA) is a natural chelator of Fe, zinc (Zn) and other metals in higher plants and NA-chelated Fe is highly bioavailable in vitro. In graminaceous plants NA serves as the biosynthetic precursor to 2' -deoxymugineic acid (DMA), a related Fe chelator and enhancer of Fe bioavailability, and increased NA/DMA biosynthesis has proved an effective Fe biofortification strategy in several cereal crops. Here we utilized the chicken (Gallus gallus) model to investigate impacts of NA-chelated Fe on Fe status and gastrointestinal health when delivered to chickens through intraamniotic administration (short-term exposure) or over a period of six weeks as part of a biofortified wheat diet containing increased NA, Fe, Zn and DMA (long-term exposure). Striking similarities in host Fe status, intestinal functionality and gut microbiome were observed between the short-term and long-term treatments, suggesting that the effects were largely if not entirely due to consumption of NA-chelated Fe. These results provide strong support for wheat with increased NA-chelated Fe as an effective biofortification strategy and uncover novel impacts of NA-chelated Fe on gastrointestinal health and functionality.

Maternal manganese activates anti-apoptotic-related gene expressions via miR-1551 and miR-34c in embryonic hearts from maternal heat stress (Gallus gallus)

MicroRNAs (miRNAs) expressions are altered by maternal stresses and nutritional status. Our previous study has demonstrated that maternal manganese (Mn) addition could protect chick embryos against maternal heat stress via enhancing anti-apoptotic ability in embryonic hearts. The objective of this study was to investigate whether this protective effect could be achieved via miRNA mechanisms, and also be sustained in offspring broilers. A completely randomized design with a 2 (maternal normal and high temperatures: 21 and 32 °C) × 2 (maternal control basal diet and the basal diet + 120 mg Mn/kg) factorial arrangement of treatments was adopted. Totally 96 broiler breeder hens were allotted to 4 treatments with 6 replicates. Subsequently, 24 hatched chicks from each maternal treatment were divided into 6 replicates. Maternal supplemental 120 mg Mn/kg reduced the increased expressions of miR-1551 and miR-34c in hearts of offspring embryos but not broilers under maternal heat stress. B-cell CLL/lymphoma 2 (BCL2) and NF-κB-inducing kinase (NIK) genes related to anti-apoptotic ability were identified as direct targets for miR-1551 and miR-34c, respectively. Under maternal heat stress, maternal supplemental 120 mg Mn/kg activated target BCL2 expression and NIK-dependent NF-κB pathway via mediating miR-1551 and miR-34c expressions in hearts of offspring embryos rather than broilers.