Effect of zinc source and picolinic acid on 65Zn uptake in an in vitro continuous-flow perfusion system for pig and poultry intestinal segments

The organic zinc with moderate chelation strength enhances the expression of related transporters in the jejunum and ileum of broilers

Our previous study demonstrated that the zinc (Zn) proteinate with moderate chelation strength (Zn-Prot M) enhanced the Zn absorption in the small intestine partially via increasing the expression of some Zn and amino acid transporters in the duodenum of broilers. However, it remains unknown whether the Zn-Prot M could also regulate the expression of related transporters in the jejunum and ileum of broilers in the above enhancement of Zn absorption. The present study was conducted to investigate the effect of the Zn-Prot M on the expression of related transporters in the jejunum and ileum of broilers compared to the Zn sulfate (ZnS). Zinc-deficient broilers (13-d-old) were fed with the Zn-unsupplemented basal diets (control) or the basal diets supplemented with 60 mg Zn/kg as ZnS or Zn-Prot M for 26 d. The results showed that in the jejunum, compared to the control, supplementation of the organic or inorganic Zn increased (P < 0.05) mRNA and protein expression of b^0,+-type amino acid transporter (rBAT), Zn transporter 10 (ZnT10), and peptide-transporter 1 (PepT1) mRNA expression and Zn transporter 7 (ZnT7) protein expression on d 28, while y+L-type amino transporter 2 (y+LAT2) mRNA and protein expression, and protein expression of ZnT7 and ZnT10 on 28 d and zrt-irt-like protein 3 (ZIP3) and zrt-irt-like protein 5 (ZIP5) on d 39 were higher (P < 0.05) for Zn-Prot M than for ZnS. In the ileum, Zn addition regardless of Zn source up-regulated (P < 0.05) mRNA expression of Zn transporter 9 (ZnT9) and ZIP3, ZIP5, and y+LAT2 protein expression on d 28, and PepT1 mRNA and protein expression, ZIP3 and y+LAT2 mRNA expression and ZnT10 protein expression on d 39. Furthermore, Zn transporter 4 (ZnT4) and ZnT9 mRNA expression and Zn transporter 1 (ZnT1) protein expression on d 28, and y+LAT2 mRNA expression and ZnT10 and PepT1 protein expression on d 39 were higher (P < 0.05) for Zn-Prot M than for ZnS. It was concluded that the Zn-Prot M enhanced the expression of the ZnT1, ZnT4, ZnT9, ZnT10, ZIP3, ZIP5, y+LAT2, and PepT1 in the jejunum or ileum of broilers compared to the ZnS.

Effect of Organic or Inorganic Mineral Premix in the Diet on Laying Performance of Aged Laying Hens and Eggshell Quality

In this study, we examined the effect of diets supplemented with organic and inorganic mineral premixes on the laying performance and eggshell quality of aged laying hens. A total of 600 68-week-old Hy-Line Brown laying hens were randomly assigned to 1 of 3 dietary treatments, repeated 5 times: Mash type basal diet, basal diet supplemented with an inorganic mineral premix (1.0 g/kg), and basal diet supplemented with an organic mineral premix (1.8 g/kg). The results showed that eggshell strength was higher (p < 0.01) in the inorganic mineral diet group than in the organic mineral and basal diet groups. Further, the levels of Fe and Mn in the liver were higher (p < 0.05) in the inorganic and organic mineral diet groups than in the basal diet group. The concentrations of Fe and Mg in the spleen were different (p < 0.05) among the treatment groups, with the highest levels reported in the organic mineral premix group. The concentrations of Cu, Zn, and Mn in the eggshell were different (p < 0.05) among the groups, with the highest levels reported in the inorganic and organic mineral premix diet groups. In conclusion, a diet containing organic mineral premix improved eggshell strength and had no detrimental effect on the laying performance of aged laying hens.

Organic zinc with moderate chelation strength enhances zinc absorption in the small intestine and expression of related transporters in the duodenum of broilers

Our previous study demonstrated that the absorption of zinc (Zn) from the organic Zn proteinate with moderate chelation strength was significantly higher than that of Zn from the inorganic Zn sulfate in the in situ ligated duodenal segment of broilers, but the underlying mechanisms are unknown. The present study aimed to determine the effect of organic Zn with moderate chelation strength and inorganic Zn on the Zn absorption in the small intestine and the expression of related transporters in the duodenum of broilers. The Zn-deficient broilers (13 days old) were fed with the Zn-unsupplemented basal diets (control) containing 25.72 and 25.64 mg Zn/kg by analysis or the basal diets supplemented with 60 mg Zn/kg as the Zn sulfate or the Zn proteinate with moderate chelation strength (Zn-Prot M) for 26 days. The results showed that the plasma Zn contents from the hepatic portal vein of broilers at 28 days and 39 days of age were increased (p < 0.05) by Zn addition and greater (p < 0.05) in the Zn-Prot M than in the Zn sulfate. On d 28, Zn addition upregulated (p < 0.05) mRNA expression of zinc transporter 1 (ZnT1), Zrt-irt-like protein 5 (ZIP5), y + L-type amino transporter 2 (y + LAT2) and b^0,+-type amino acid transporter (rBAT), zinc transporter 4 (ZnT4) protein expression, and zinc transporter 9 (ZnT9) mRNA and protein expression in the duodenum. Moreover, ZnT9 mRNA expression, ZnT4, ZIP5, and rBAT protein expression, zinc transporter 7 (ZnT7), and y + LAT2 mRNA and protein expression in the duodenum of broilers on 28 days were higher (p < 0.05) in the Zn-Prot M than in the Zn sulfate. On d 39, supplemental Zn increased (p < 0.05) peptide-transporter 1 (PepT1) mRNA expression and y + LAT2 protein expression, while the mRNA expression of ZnT7 and Zrt-irt-like protein 3 (ZIP3) were higher (p < 0.05) for the Zn-Prot M than for the Zn sulfate in the duodenum. It was concluded that the Zn-Prot M enhanced the Zn absorption in the small intestine partially via upregulating the expression of ZnT4, ZnT7, ZnT9, ZIP3, ZIP5, y + LAT2, and rBAT in the duodenum of broilers.

Organic zinc absorption by the intestine of broilers in vivo

In Expt 1, a Zn-unsupplemented basal diet (control) and the basal diet supplemented with one of four different Zn sources, including ZnSO4, Zn-amino acid chelate with a weak chelation strength (Zn-AA W), Zn-protein chelate with a moderate chelation strength (Zn-Pro M) and Zn-protein chelate with a strong chelation strength (Zn-Pro S) were fed to broiler chickens from days 14 to 28. On day 28, Zn content in plasma from the hepatic portal vein increased (P0·05) and Zn-AA W(P<0·04) were higher than those for ZnSO4. These findings indicate that organic Zn absorption (especially Zn-Pro S) in intact living broilers was more effective than that of inorganic Zn; organic Zn absorption in the ligated duodenal segment was a saturable carrier-mediated process similar to that of ZnSO4. Moreover, except for MT, there might be other Zn transporters involved in Zn absorption that are affected by different Zn sources.

Effects of Organic and Inorganic Forms of Manganese, Zinc, Copper, and Chromium on Bioavailability of These Minerals and Calcium in Late-Phase Laying Hens

In the present study, the effects of dietary supplementation of organic and inorganic Mn, Zn, Cu, and Cr mixtures using two different levels (80, 60, 5, and 0.15 mg/kg and 40, 30, 2.5, and 0.07 mg/kg, respectively) on the bioavailability of these trace minerals and Ca in late-phase laying hens were evaluated. Three hundred and sixty laying hens (Barred Rock) at 50 weeks of age were used, and the duration of study was 16 weeks. Each of the four dietary regimes was randomly assigned to six replicates, which included 15 hens each. Organic trace minerals were provided as methionine chelates; inorganic Mn, Zn, and Cr were provided as oxides; and Cu was provided as sulfate. The organic form significantly increased the concentrations of serum Mn, Zn, Cu, and Ca; egg Mn, Zn, Cu, and Cr; and eggshell Zn and Cr compared with the inorganic form. However, the form of trace minerals did not affect the concentrations of serum Cr and eggshell Mn, Cu, and Ca. High-level addition of trace minerals significantly increased serum Mn and Zn; egg Mn, Zn, Cu, and Cr; and eggshell Mn, Zn, and Cu concentrations compared with low-level addition but did not affect serum Cu, Cr, and Ca or eggshell Cr and Ca concentrations. While the organic form reduced the excretion of Mn, Zn, Cu, Cr, and Ca, the high-level supplement increased Mn, Zn, and Cu excretion. The addition level did not affect Cr and Ca excretion. These results demonstrate that dietary supplementation of an organic Mn, Zn, Cu, and Cr mixture increases the bioavailability of Mn, Zn, Cu, Cr, and Ca compared with inorganic sources and that a lower level of trace mineral supplementation results in lower mineral excretion, particularly in an organic form.

Effect of intravenously injected zinc on tissue zinc and metallothionein gene expression of broilers

1. The effect of intravenously injected zinc (Zn) on tissue Zn concentrations and pancreas metallothionein (MT) gene expression in broilers was investigated to detect differences in the tissue utilisation of Zn from different Zn sources. 2. A total of 432 male chickens were randomly allotted on d 22 post-hatch to one of nine treatments in a completely randomised design. Chickens were injected with either a 0.9% (w/v) NaCl solution (control) or a saline solution supplemented with Zn sulphate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M) or strong (Zn-Pro S) chelation strengths at two injected Zn dosages calculated according to two Zn absorbability levels (6 and 12%). 3. Bone and pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations increased on d 6 and 12 after Zn injections as the injected Zn dosages increased. Chickens injected with the Zn-Pro S had lower bone Zn concentration than those injected with the Zn-Pro M or Zn-AA W on d 6 after injections. However, no differences among Zn sources were observed in bone Zn concentration on d 12 after injections, pancreas Zn concentrations, pancreas MT mRNA levels and MT concentrations on both d 6 and d 12 after injections. 4. It was concluded that the injected Zn-Pro S was the least favourable for bone Zn utilisation of broilers. The pancreas Zn concentration and pancreas MT gene expressions might not be sensitive enough to detect differences in the tissue utilisation of injected Zn in broilers between organic and inorganic Zn sources or among organic Zn sources.

Effects of manganese source and calcium on manganese uptake by in vitro everted gut sacs of broilers' intestinal segments

Three experiments were conducted with everted gut sacs to investigate the effects of Mn source and Ca on Mn absorption in different intestinal segments of broilers. In Experiment 1, the Mn uptake by everted sacs of duodenum, jejunum, and ileum after different incubation times was compared to determine an optimum incubation time. In Experiment 2, 8 different Mn sources, including MnSO4, organic Mn sources (Mn-amino acid chelates, Mn-amino acids complexes with different complex strength), and mixtures of MnSO4 with Gly or Met were used to assess the effect of Mn source on Mn uptake. In Experiment 3, the effect of Ca in media on the uptake of Mn from MnSO4 and Mn-amino acids complexes was investigated. The uptake percentages of Mn by everted ileal sacs were significantly higher than those by duodenal and jejunal sacs. The uptake of Mn as Mn-Met chelate was significantly higher than that of Mn as Mn-Gly chelate. The uptake percentages of Mn as Mn-amino acid complex with moderate complex strength (Mn-AA A) and Mn-amino acid complex with strong complex strength (Mn-AA B) were significantly higher than that of Mn as MnSO4. The uptake of Mn as Mn-AA B by jejunal sacs was significantly higher than that of Mn as Mn-AA A in media containing high level of Ca. The uptake percentages of Mn at high Ca level were significantly higher than those at normal level. The results indicate that when incubated in vitro, ileum was the main site of Mn absorption for broilers. The absorption of Mn as organic sources were higher than that of Mn as inorganic Mn. The absorption of Mn as Mn-AA B with strong complex strength by jejunal sacs was higher than that of Mn as Mn-AA A with moderate complex strength in media containing high level of Ca. As a ligand, Met was more effective in facilitating Mn absorption than Gly. Furthermore, the transportation of Mn through intestinal cells was enhanced by adding Ca as CaCl2 to the buffer solutions.

Responses of broilers to dietary zinc concentrations and sources in relation to environmental implications

1. Since high concentrations of zinc are associated with reduced crop yields, environmental concerns are emerging regarding zinc accumulation in areas where poultry production is prevalent. This study investigates growth performance and zinc utilisation during the life cycle of broilers when diets were supplemented with various concentrations of zinc from two different sources. 2. A total of 740 Cobb 500 1-d-old male broiler chicks was randomly distributed into 88 battery cages. Excreta were collected over a 48-h period on d 10, 17, 24, 31, 38, and 45 to measure zinc excretion on a dry matter basis. 3. During the 45-d experimental period, broilers were given a maize-soybean meal basal diet (30 mg/kg zinc) supplemented with 0, 20, 40, and 80 mg/kg of zinc from zinc sulphate, Availa Zn amino acid complex, or an equal combination of zinc sulphate and Availa Zn amino acid complex. 4. Progressive additions of zinc to the basal diet significantly increased body weight gain of broilers, but did not affect feed conversion or mortality. Optimum body weight gain was achieved at 80 mg/kg supplemental zinc, which exceeds the NRC recommendations of 40 mg/kg. 5. During each excreta collection period, increased supplemental zinc concentrations significantly increased zinc excretion. However, the zinc source did not influence zinc utilisation. 6. As compared with zinc sulphate supplementation, the cumulative zinc excretion data indicate that adding zinc to the basal diet in the form of Availa Zn amino acid complex decreased zinc excretion.

Supplementation of a corn-soybean meal diet with manganese, copper, and zinc from organic or inorganic sources improves eggshell quality in aged laying hens

An experiment was conducted to evaluate the effects on eggshell quality of supplementing the diet of laying hens with a combination of Zn, Mn, and Cu from organic or inorganic sources. Three groups of hens, aged 32, 60, and 69 wk were fed a corn-soybean basal diet containing 32.6 mg/kg Zn, 24.7 mg/kg Mn, and 4.95 mg/kg Cu or a basal diet supplemented with 30-30-5 and 60-60-10 mg/kg of Zn, Mn, and Cu, respectively. Addition of Zn, Mn, and Cu in combination increased their concentrations in egg yolk and slightly decreased egg weight during some sampling from aged hens. The Zn, Cu, and Mn dietary supplementation did not affect the following measures of eggshell quality: percentage eggshell, eggshell index (shell weight per unit surface area), and eggshell stiffness. However, there was a small increase in elastic modulus of the eggs from one group of the older hens due to supplementation with Zn, Mn, and Cu. More consistently we observed improved breaking strength and fracture toughness (resistance to fracture) in the two oldest groups of hens at 1, 5, and 9 wk after introduction of the experimental diets. The effect was observed regardless of the source of trace elements.

Dietary factors influencing zinc absorption

Marginal zinc deficiency and suboptimal zinc status have been recognized in many groups of the population in both less developed and industrialized countries. Although the cause in some cases may be inadequate dietary intake of zinc, inhibitors of zinc absorption are most likely the most common causative factor. Phytate, which is present in staple foods like cereals, corn and rice, has a strong negative effect on zinc absorption from composite meals. Inositol hexaphosphates and pentaphosphates are the phytate forms that exert these negative effects, whereas the lower phosphates have no or little effect on zinc absorption. The removal or reduction of phytate by enzyme (phytase) treatment, precipitation methods, germination, fermentation or plant breeding/genetic engineering markedly improves zinc absorption. Iron can have a negative effect on zinc absorption, if given together in a supplement, whereas no effect is observed when the same amounts are present in a meal as fortificants. Cadmium, which is increasing in the environment, also inhibits zinc absorption. The amount of protein in a meal has a positive effect on zinc absorption, but individual proteins may act differently; e.g., casein has a modest inhibitory effect of zinc absorption compared with other protein sources. Amino acids, such as histidine and methionine, and other low-molecular-weight ions, such as EDTA and organic acids (e.g., citrate), are known to have a positive effect on zinc absorption and have been used for zinc supplements. Knowledge about dietary factors that inhibit zinc absorption and about ways to overcome or remove these factors is essential when designing strategies to improve the zinc nutrition of vulnerable groups.

The effects of dietary ligands on zinc uptake at the porcine intestinal brush-border membrane

Intestinal brush-border-membrane vesicles were prepared from the porcine small bowel by magnesium precipitation and differential centrifugation, and were functionally intact. The influence of dietary ligands on 65Zn uptake was determined using a 65Zn concentration of 5 microM, an incubation time of 1 min and a reaction temperature of 27 degrees, with a rapid filtration technique. At this low Zn concentration the addition of an excess of folate, histidine or glucose had no effect on Zn uptake. Addition of picolinate, citrate and phytate to the incubation medium significantly reduced Zn uptake at all concentrations of ligand examined. Any inhibitory effects of folic acid in vivo may thus be due to a mucosal rather than lumen interaction. Those ligands inhibiting absorption may have done so through the formation of Zn-ligand complexes, which are either insoluble, or which reduce the binding of Zn to its mucosal receptor. This in vitro model of Zn absorption is useful for comparing the effects of potential Zn-binding ligands in the diet.