Determination of daily dietary intake of chromium by duplicate diet sampling:In vitroavailability study

Effects of nanoparticle chromium mixed with γ-polyglutamic acid on the chromium bioavailability, growth performance, serum parameters and carcass traits of pigs

Because chromium is a mineral that is difficult to absorb, nanotechnology was used to produce nanoparticle trivalent chromium, which has a reduced particle size and increased surface area to increase chromium bioavailability. The aim of the present study was to investigate the effect of dietary supplementation nanoparticle trivalent chromium with or without γ-polyglutamic acid (γ-PGA) on the chromium bioavailability, growth performance, serum parameters and carcass traits of pigs. In Trial 1, eight growing pigs (Landrace × Yorkshire × Duroc; LYD) with an initial average weight of 51.3 ± 2.0 kg were used in a 4 × 4 Latin square design as the control group (without chromium supplements), the chromium picolinate group (CrPic), the nanoparticle chromium picolinate group (NanoCrPic) and the nanoparticle chromium picolinate mixed with γ-polyglutamic acid (NanoCrPic–PGA) group. Chromium was added at a level of 200 μg/kg to a basal diet containing 728 µg Cr/kg DM, using different forms of chromium, so as to evaluate the chromium bioavailability. The results of Trial 1 indicated that the bioavailability of the supplemented chromium was as follows: NanoCrPic–PGA > NanoCrPic > CrPic (P < 0.05). In Trial 2, 64 LYD growing pigs (average bodyweight 74.46 ± 3.9 kg) were randomly allotted to the same four dietary treatment groups as in Trial 1 and the same levels of chromium were added to the diet. Each group contained four pens and there were four pigs in each pen. The experimental results indicated that the gain:feed ratio in the NanoCrPic–PGA group was better than that in the NanoCrPic group (P < 0.001). The serum chromium concentrations in the NanoCrPic–PGA group were higher than in the control group (P < 0.05), the serum insulin concentration in the chromium supplementation groups was lower than that in the control group (P < 0.05), and blood glucose in the NanoCrPic group was lower than that in the control group (P < 0.05). The carcass traits were not affected by chromium supplementation. In conclusion, nanoparticle trivalent chromium, either alone or together with γ-PGA, improved chromium bioavailability and feeding effectiveness.

Charge-transfer interactions of Cr species with DNA

Interactions of Cr species with nucleic acids in living organisms depend strongly on Cr oxidation state and the environmental conditions. As the effects of these interactions range from benign to pre-mutagenic to carcinogenic, careful assessment of the hazard they pose to human health is necessary. We have investigated methods that would enable quantifying the DNA damage caused by Cr species under varying environmental conditions, including UV, O₂, and redox potential, using simple instrumental techniques which could be in future combined into a field-deployable instrumentation. We have employed electrochemical quartz crystal nanogravimetry (EQCN), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) to evaluate the extent of DNA damage expressed in terms of guanine oxidation yield (η) and changes in specific characteristics provided by these techniques. The effects of the interactions of Cr species with DNA were analyzed using a model calf thymus DNA (ctDNA) film on a gold electrode (Au@ctDNA) in different media, including: (i) Cr(VI), (ii) Cr(VI) reduced at -0.2V, (iii) Cr(III)+UV radiation+O₂, and Cr(III), obtaining the η values: 7.4±1.4, 1.5±0.4, 1.1±0.31%, and 0%, respectively, thus quantifying the hazard posed. The EIS measurements have enabled utilizing the decrease in charge-transfer resistance (R_ct) for ferri/ferrocyanide redox probe at an Au@ctDNA electrode to assess the oxidative ctDNA damage by Cr(VI) species. In this case, circular dichroism indicates an extensive damage to the ctDNA hydrogen bonding. On the other hand, Cr(III) species have not induced any damage to ctDNA, although the EQCN measurements show an electrostatic binding to DNA.

Effects of nanoparticle chromium on chromium absorbability, growth performance, blood parameters and carcass traits of pigs

The aim of this study was to investigate the effect of dietary supplementation of nanoparticle trivalent chromium on chromium absorbability, growth performance, blood parameters and carcass characteristics of pigs. In Trial 1, five growing pigs (Landrace × Yorkshire × Duroc) (initial average weight was 31.3 ± 2.0 kg) were used in a 5 × 5 Latin square design as the Control group (without supplement of chromium), the chromium chloride group (CrCl3), the chromium picolinate group (CrPic), the nanoparticle chromium chloride group (NanoCrCl3), and the nanoparticle chromium picolinate group (NanoCrPic). The pigs were adapted for 7 days, followed by a 5-day test period and a collection period. The chromium was added at a 200 μg/kg level to the diet using different chromium sources for evaluating the chromium absorbability. The results of Trial 1 indicated that there were no differences in feed components digestibility among the groups, but the absorbability of chromium in the NanoCrPic (27.5%) group was the highest, whereas that in the CrCl3 group was the lowest (4.91%). Moreover, the chromium source, nanoparticle size and interaction effects were observed between these two factors (P < 0.001). In Trial 2, 60 Landrace × Yorkshire × Duroc growing pigs (average bodyweight was 76.7 ± 4.5 kg) were randomly allotted to five dietary treatment groups as used in Trial 1, each group with four pens (three pigs/pen). The study was conducted for 60 days. Their growth performance, carcass and meat traits were also evaluated. Trial 2 results indicated that feed intake in the chromium-added groups was greater (P < 0.007) than that in the Control group. The average daily bodyweight gain in the chromium-added groups was greater than that in the Control group (P = 0.046). The serum non-esterified fatty acids level was lower (P < 0.0001) in the NanoCr groups. Serum chromium concentration was increased by dietary chromium supplementation, and the chromium source, nanoparticle size and their interaction effects (P < 0.001) were observed. The average back fat thickness in the CrPic and NanoCrPic groups was lower (P < 0.05) than that of the Control group. Meat chromium content was elevated by dietary chromium supplementation, particularly in the CrPic and NanoCrPic groups (P < 0.05). The chromium source, nanoparticle size and interaction effects between these two factors were observed in serum non-esterified fatty acids and chromium content. The muscle chromium content also affected by chromium source and displayed interaction of source and nanoparticle size. In conclusion, chromium supplementation could increase feed intake and average daily gain, serum and longissimus muscle chromium content, as well as reduce back fat thickness of pigs. In addition, nanoparticle organic trivalent chromium could increase chromium absorbability and decrease serum non-esterified fatty acids concentrations. Organic form was better than inorganic form in chromium absorbability, serum and longissimus muscle chromium content and average back fat thickness.

Melatonin administration in diabetes: regulation of plasma Cr, V, and Mg in young male Zucker diabetic fatty rats

The use of melatonin, a neurohormone present in plants, represents an exciting approach for the maintenance of optimum health conditions. Melatonin administration ameliorates glucose homeostasis in Zucker diabetic fatty (ZDF) rats. The objective of this study was to investigate the effects of melatonin in diabetes in relation to the levels and regulation of plasma chromium (Cr), vanadium (V), and magnesium (Mg) in Zucker diabetic fatty (ZDF) and Zucker lean (ZL) rats. At the age of 6 weeks, ZDF (n = 30) and ZL (n = 30) groups were each subdivided into three groups: control (C) (n = 10), vehicle-treated (V') (n = 10) and melatonin-treated (M) (10 mg kg(-1) per day; n = 10) groups for a 6 week period. After treatment, plasma mineral concentrations were measured by flame (Mg) and electrothermal (Cr and V) atomic absorption spectrometry. No significant differences were found between the C and V' groups (p > 0.05). Plasma Mg levels were significantly lower in C-ZDF vs. C-ZL rats, demonstrating the presence of hypomagnesemia in this diabetes mellitus model. Plasma V and Cr levels were significantly higher in M-ZDF vs. C-ZDF rats. Plasma Mg levels in ZDF rats were not affected by melatonin treatment (p > 0.05). Melatonin administration ameliorates the diabetic status of ZDF rats by enhancing plasma Cr and V concentrations. This appears to be the first report of a beneficial effect of melatonin treatment on plasma Cr and V regulation in ZDF rats.

The probiotic bacterial strain Lactobacillus fermentum D3 increases in vitro the bioavailability of Ca, P, and Zn in fermented goat milk

We determined calcium, magnesium, phosphorus and zinc levels in a total of 27 samples of commercial goat- and cow-milk fermented products and 9 samples of a goat-milk fermented product with addition of a probiotic bacterial strain, Lactobacillus fermentum D3, manufactured experimentally by our research group. Atomic absorption spectroscopy with flame atomization and UV/VIS spectrophotometry were used as analytic techniques. The results of an in vitro digestion process showed that the bioavailability of calcium, phosphorus, and zinc was significantly higher in our fermented milk containing the probiotic bacterial strain than it was in commercial goat-milk fermented products. Furthermore, our product showed a significantly higher bioavailability of calcium and zinc compared to goat- and cow-milk fermented products made with other microorganisms. We conclude that, in in vitro assays, strain D3 seems to increase the bioavailability of these minerals and that this new product may constitute a better source of bioavailable minerals compared to other products already on the market.

Chromium(VI) but not chromium(III) species decrease mitoxantrone affinity to DNA

Binding of mitoxantrone (MXT) to double-stranded DNA has been investigated as a model drug-DNA binding system to evaluate the effects of various forms of chromium on the binding properties. We have found that Cr(III), which binds strongly to DNA, does not affect the MXT affinity to DNA. In contrast, Cr(VI), in the form of chromate ions CrO(4)(2-), decreases the MXT affinity to DNA despite electrostatic repulsions with phosphate-deoxyribose chains of DNA. The MXT-DNA binding constant was found to decrease from (1.96 ± 0.005) × 10(5) to (0.77 ± 0.018) × 10(5) M(-1) for Cr(VI) concentration changing from 0 to 30 μM. The influence of Cr(VI) on MXT-DNA binding has been attributed to the oxidation of guanine residue, thus interrupting the intercalation of MXT into the DNA double helix at the preferential CpG intercalation site. This supposition is corroborated by the observed increase in the MXT binding site size from 2 bp (base pairs) to 4-6 bp in the presence of Cr(VI). The measurements of the MXT-DNA binding constant and the MXT binding site size on a DNA molecule have been carried out using spectroscopic, voltammetric, and nanogravimetric techniques, providing useful information on the mechanism of the interactions.

Dialysability of magnesium and calcium from hospital duplicate meals: influence exerted by other elements

Total and dialysable magnesium and calcium levels and corresponding dialysabilities were measured in duplicate meals (n = 108) during 36 consecutive days. The interaction exerted by other nutrients and energy on them was also performed. Total mean magnesium and calcium fractions of 113.9 +/- 98.3 and 337.2 +/- 278.9 mg/meal respectively, were found. The Mg and Ca levels supplied by meals are positively (p < 0.05) correlated with macronutrient contents (carbohydrates and proteins). The mean dialysable Mg and Ca fractions were 56.9 +/- 36.3 and 127.4 +/- 112.3 mg/meal (50.4 +/- 13.2 and 37.8 +/- 10.7% as dialysabilities, respectively). Total Mg and Ca levels are significantly correlated with corresponding element dialysabilities (p < 0.05). For both minerals, significant correlations between their total and dialysable fractions and between their dialysable level and dialysabilities were noted (p < 0.01). The mean Mg and Ca daily dietary intakes (DDI) were 341.7 +/- 68.0 and 1,011.6 +/- 424.4 mg/day, respectively. For Ca and Mg the existence of similarities in their behaviour in meals and absorptive processes has been found. Duplicate meals with raw vegetables are good sources of bioaccessible Mg. High Ca dialysability has been found in the analysed meals. The fish and products constitute a good source of bioaccessible Ca. Mg, Ca, zinc, and chromium levels enhanced significantly the Mg dialysability. The Ca dialysability rose significantly with dialysable Ca and chromium fractions (p < 0.05).

Iron dialyzability from hospital duplicate meals: daily intake

Both total and dialyzable iron levels and corresponding dialyzability were determined in 108 duplicate meals during 36 consecutive days. Total mean iron fraction of 5.90 +/- 4.97 mg was found in the meals. The iron supplied by the meals is directly and significantly (p < 0.05) correlated with macromicronutrient content (carbohydrates, fiber, and protein). The mean iron dialyzability (4.81 +/- 3.25%) was low and not significantly different among the three primary meals (breakfast, lunch, and dinner). Significant interactions of several minerals on iron levels were found (p < 0.05). Iron dialyzability was only statistically influenced by zinc dialyzability in meals (p < 0.05). The dialyzed iron fraction present in meals was significantly correlated with protein and ascorbic acid levels (p < 0.01). The mean iron daily dietary intake was 17.7 +/- 6.91 mg. The hospital meals provided enough iron. Foods of animal origin are primary sources of iron in diet.