Effect of Selenium Supplementation on Blood Status and Milk,Urine, and Fecal Excretion in Pregnant and Lactating Camel

Ten pregnant female camels divided into two groups received, after a 2-week adaptation period, an oral selenium (Se) supplementation (0 and 2 mg, respectively) under sodium selenite form for 6 months from the three last months of gestation up to the three first months of lactation. Feed intake was assessed daily. Blood samples and body weight were taken on a biweekly basis, both in dams and their camel calves after parturition. Feces and urine samples were collected monthly and milk on a biweekly basis. The Se concentration in serum increased significantly in the supplemented group and was threefold higher than the concentration compared to the control group, respectively, 305.9 ± 103.3 and 109.3 ± 33.1 ng/mL. The selenium concentration increased in similar proportion in milk (86.4 ± 39.1 ng/mL in the control group vs 167.1 ± 97.3 ng/mL in treated group), in urine, and feces. The gluthathione peroxidase (GSH-Px) activity varied between 18.1 ± 8.7 IU/g hemoglobin (Hb) in control group and 47.5 ± 25.6 IU/g Hb in treated group but decreased after parturition in both groups. Vitamin E did not change significantly and was, on average, 1.17 ± 0.72 and 1.14 ± 0.89 ng/mL in the control and treated groups, respectively. Significant correlations were reported between serum Se, milk Se, GSH-Px, and fecal and urinary excretion or concentration. Blood values in camel calves were similar to those of the dams. The results seemed to confirm the sensitivity of camel to Se supplementation with an important increase of selenium in serum and milk.     

Longitudinal study of the dietary selenium intake of exclusively breast-fed infants during early lactation in Korea and Japan.

213 samples of human breast milk were collected from 51 healthy Korean women. Selenium content of the samples was determined by atomic absorption spectrometry with hydride generation. The selenium content of Korean milk decreased with increase of days after birth: The arithmetic mean of selenium content was higher in colostrum (< 4 days) 34 micrograms/kg (SD +/- 11, n = 44) than in transitional milk 21 micrograms/kg (SD +/- 8, n = 78) or in mature milk (> 10 days) 13 micrograms/kg (SD +/- 6, n = 91). The daily dietary selenium intake of 0-1 month aged Korean infants fed on breast milk is estimated to be around 10 micrograms per day (3 micrograms/kg body weight) regardless of days postpartum, resulting from the calculation of our selenium data and daily milk intake during early lactation. The same result on selenium intake for Japanese newborns, as well as Korean infants, is also estimated to be around 10 micrograms per day (3 micrograms/kg body weight) regardless of days postpartum.     

Mercury Concentration in Breast Milk and Infant Exposure Assessment During the First 90 Days of Lactation in a Midwestern Region of Brazil

Breast milk samples collected from 18 nursing mothers between the 15th and 90th day of lactation were digested in nitric acid in a microwave, and total mercury (THg) levels were quantified by atomic fluorescence spectrometry. Participants responded to a 24-h dietary recall questionnaire on the 74th and 76th day of lactation and to a Food Frequency Questionnaire querying the frequency of fish intake over the last 90 days. Usual intake was estimated using the PC-SIDE software package. A meal of fish was offered on the 75th day of lactation. Mothers’ individual mean THg levels ranged from <0.76 to 22.7 ng/mL during the period, and the mean level for all samples (n?=?142) was 6.47?±6.04 ng/mL. The multilevel mixed linear model used showed high heterogeneity of the mercury levels among the mothers, and THg levels did not change significantly over the period under study. However, a significant increase in THg levels was observed after the intervention with the fish meal. Exposure increased for most infants on the 90th day of lactation, with intakes exceeding the THg provisional tolerable weekly intake (PTWI) at least once during the period for 77.8 % of samples. Mothers consumed mostly food from the fat and grain groups, and a significant correlation was detected between consumption of food of these groups and breast milk THg levels (p?=?0.006 and 0.007). A significant correlation was also found between vegetable consumption and carbohydrate intake and THg levels in the samples (p?=?0.015 and 0.045, respectively). No correlation was found between mothers’ daily fish consumption frequency and THg levels. Although this study showed that mercury intake by infants during lactation may exceed the toxicologically safe exposure level (PTWI), we nevertheless believe that the benefits of lactation for both the mother and the infant outweigh the eventual risks that this exposure may represent.     

Sex, age, geographical location, smoking, and alcohol consumption influence serum selenium concentrations in the USA: third National Health and Nutrition Examination Survey, 1988-1994.

Selenium has been reported to reduce the risk for heart diseases and cancer. We examined the association of sex, age, geographical location, serum cotinine concentrations, a measure of smoking intensity, and alcohol consumption with serum selenium concentrations in the third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. Study sample consisted of 14,619 apparently healthy individuals (male: 7,102; female: 7,517) aged 14 to >90 years. Sex, age, geographical location, serum cotinine concentrations, and alcohol consumption significantly influenced serum selenium concentrations (P < 0.05). The mean (+/- standard error) serum selenium concentration in men (124.5 +/- 0.20 ng/mL) was significantly higher than in women (122.0 +/- 0.20 ng/mL) (P < 0.0001). Men in the 31-50 y age group had the highest mean serum selenium concentration. In the same age group, women had the lowest mean serum selenium concentration. In both sexes, participants living in the Midwest and West had significantly higher serum selenium concentrations than those living in South and Northeast geographical locations. Serum cotinine was negatively associated with serum selenium concentrations in both men (beta = -0.0108; P < 0.0001 for trend) and women (beta = -0.0097; P < 0.0001 for trend). Alcohol consumption is positively associated with serum selenium in women (beta = 0.0462; P = 0.0044 for trend) but not in men (beta = 0.0015; P = 0.8496 for trend). Although, sex, age, geographical location, smoking, and alcohol intake influenced serum selenium concentrations, clinically low serum selenium concentrations are not common in the USA.     

A physiological role of breast milk leptin in body weight control in developing infants

Objective: Leptin, a hormone that regulates food intake and energy metabolism, is present in breast milk. The aim of this study was to determine whether milk leptin concentration is correlated with maternal circulating leptin and BMI and with body weight gain of infants. Research Methods and Procedures: A group of 28 non‐obese women (BMI between 16.3 and 27.3 kg/m²) who breast‐fed their infants for at least 6 months and their infants were studied. Venous blood and milk samples were obtained from mothers at 1, 3, 6, and 9 months of lactation, and leptin concentration was determined. Infant body weight and height were followed until 2 years of age. Results: During the whole lactation period, milk leptin concentration correlated positively with maternal plasma leptin concentration and with maternal BMI. In addition, milk leptin concentration at 1 month of lactation was negatively correlated with infant BMI at 18 and 24 months of age. A better negative correlation was also found between log milk leptin concentration at 1 and at 3 months of lactation and infant BMI from 12 to 24 months of age. Discussion: We concluded that, in a group of non‐obese mothers, infant body weight during the first 2 years may be influenced by milk leptin concentration during the first stages of lactation. Thus, moderate milk‐borne maternal leptin appears to provide moderate protection to infants from an excess of weight gain. These results seem to point out that milk leptin is an important factor that could explain, at least partially, the major risk of obesity of formula‐fed infants with respect to breast‐fed infants.     

Human exposure to mycotoxins in Egypt

This investigation examined the exposure of Egyptian infants to Aflatoxin M₁ (AfM₁) and of lactating mothers to Aflatoxin B₁, using AfM₁ in human milk as a biomarker for exposure to AfB₁. The presence of ochratoxin A (OA) in human milk was also investigated to determine the levels of infants exposure to OA from human milk. The results indicated that AfM₁ was found in 66 (55 %) of 120 human milk samples with a mean of 0.3 ± 0.53 ng/mL (range 0.02 to 2.09 ng/mL). OA was found in 43 (35.8 %) of 120 human milk samples with a mean of 21.1 ± 13.7 ng/mL (range 5.07 to 45.01 ng/mL), which will cause a daily intake of OA from human milk exceeding the suggested tolerable dose of 5 ng/kg_-1 of OA body weight. On the other side AfM₁ was found in 25 % of blood samples (5 out of 20 samples), at a mean of 1.18 ng/mL, but it was detected only in one urine sample (1 out of 20 samples). OA was detected only in 2 out of 13 blood samples (15.4 %) with an average 3.67 ng/mL. Whereas OA was not detected in all analyzed urine samples.     

Plasma selenium levels in healthy blood bank donors in the central-eastern part of Belgium

Graphite furnace atomic absorption spectrometry, with Zeeman background correction and after improved matrix modification, was used to measure the plasma selenium content of healthy blood bank donors in the central part of Belgium.

The mean plasma selenium concentration of 80 men and 80 women was 79.7±4.4 ng/mL with a range of 55.0–117.4 ng/mL.

There was no gender difference observed. Plasma selenium level was significantly highest for the adult group, aged 45–64 years, compared to the others, except the young adults (18–24 years).

The mean plasma selenium concentration measured corresponded well with literature data for Belgium. The obtained values were found to be in the medium range, compared with recent literature values for the European countries.     

Human and bovine lactoferrins in the milk of recombinant human lactoferrin-transgenic dairy cows during lactation

Seven Friesian human lactoferrin (hLf)-transgenic primiparous dairy cows expressing recombinant hLf (rhLf) in their milk were included in the study. After calving, concentrations of rhLf and bovine LF (bLf) in the milk, somatic cell count and milk yield were determined. The concentration of rhLf was found to be constant, about 2.9 mg/mL, throughout the early lactation period of 3 months. The concentration of bLf in colostrum was higher after calving, but decreased rapidly during the first days of lactation. The mean concentration of bLf was 0.15 mg/mL, but concentrations varied between cows from 0.07 mg/mL to 0.26 mg/mL. Based on that, it may be possible to improve the non-specific host defence mechanism in the mammary gland of dairy cows by enhancing the content of rhLf in the milk.     

Effects of dietary crude protein concentration on animal performance and nitrogen utilisation efficiency at different stages of lactation in Holstein-Friesian dairy cows

Nitrogen (N) excretion from livestock production systems is of significant environmental concern; however, few studies have investigated the effect of dietary CP concentration on N utilisation efficiency at different stages of lactation, and the interaction between dietary CP levels and stages of lactation on N utilisation. Holstein-Friesian dairy cows (12 primiparous and 12 multiparous) used in the present study were selected from a larger group of cows involved in a whole-lactation study designed to examine the effect of dietary CP concentration on milk production and N excretion rates at different stages of lactation. The total diet CP concentrations evaluated were 114 (low CP), 144 (medium CP) and 173 (high CP) g/kg DM, with diets containing (g/kg DM) 550 concentrates, 270 grass silage and 180 maize silage. During early (70–80 days), mid- (150–160 days) and late (230–240 days) lactation, the same 24 animals were transferred from the main cow house to metabolism units for measurements of feed intake, milk production and faeces and urine outputs. Diet had no effect on BW, body condition score, or milk fat, protein or lactose concentration, but DM intake, milk yield and digestibilities of DM, energy and N increased with increasing diet CP concentration. The effect of diet on milk yield was largely due to differences between the low and medium CP diets. Increasing dietary CP concentration significantly increased urine N/N intake and urine N/manure N, and decreased faecal N/N intake, milk N/N intake and manure N/N intake. Although increasing dietary CP level significantly increased urine N/milk yield and manure N/milk yield, differences in these two variables between low and medium CP diets were not significant. There was no significant interaction between CP level and stage of lactation on any N utilisation variable, indicating that the effects of CP concentration on these variables were similar between stages of lactation. These results demonstrated that a decrease in dietary CP concentration from high (173 g/kg DM) to medium level (144 g/kg DM) may be appropriate for Holstein-Friesian dairy cow to maintain milk production efficiency, whilst reducing both urine N and manure N as a proportion of N intake or milk production.     

Association of dietary and serum selenium concentrations with glucose level and risk of diabetes mellitus: A cross sectional study of national health and nutrition examination survey, 1999-2006

BackgroundThe associations among dietary selenium intake, serum selenium concentration, plasma glucose and glycosylated hemoglobin levels, and diabetes risk remain controversial. This study aimed to evaluate these associations in adults from the United States.MethodsWe conducted a cross-sectional study of participants aged 18 years and older who participated in the National Health and Nutrition Examination Survey. Between 1999 and 2006, a total of 41,474 participants were initially included in this study. Multivariable linear or logistic regression analysis was used to investigate the association between dietary selenium intake and serum selenium concentrations, glucose level, and diabetes risk.ResultsThe average age of the participants was 30.32 ± 23.95 years, and 48.72 % were men. Their mean dietary selenium intake and mean serum selenium concentration were 98 ± 55 μg per day and 129 ± 22 ng/mL, respectively. Compared with t he lowest quartile of dietary selenium intake, the highest quartile was associated with elevated plasma glucose levels (β = 2.412, 95 % confidence interval [CI]: 0.420, 4.403, P = 0.018), glycosylated hemoglobin levels (β = 0.080, 95 % CI: 0.041, 0.119, P < 0.001), and diabetes risk (odds ratio [OR] = 2.139, 95 % CI: 1.763, 2.596, P < 0.001). Higher serum selenium was also associated with increased plasma glucose levels (β = 12.454, 95 % CI: 4.122, 20.786, P = 0.003) and glycosylated hemoglobin levels (β = 0.326, 95 % CI: 0.187, 0.465, P < 0.001). A generalized additive model with a spline curve suggested a nonlinear relationship between dietary selenium intake, serum selenium and glucose levels, and diabetes risk.ConclusionsDietary selenium intake and serum selenium were positively associated with elevated levels of plasma glucose and glycosylated hemoglobin, and the relationships were nonlinear. Additional selenium supplementation for patients with diabetes may not be recommended.     

Development of a sandwich ELISA assay for measuring bovine soluble type II IL-1 receptor (IL1R2) concentration in serum and milk

The IL1R is composed of two kinds of molecule, type I (IL1R I) and type II (IL1R2). IL1R1 contributes to IL-1 signaling, whereas the IL1R2 has no signaling property and acts as a decoy for IL-1. In this study, we developed a bovine IL1R2-specific sandwich ELISA to examine the sIL1R2 concentration in serum and milk from dairy cows. The concentration of colostral IL-1beta was examined to estimate the correlation to sIL1R2. The results showed that the sIL1R2 concentration in sera and milk changes with the stages of lactation. The serum sIL1R2 concentrations were 5.56+/-0.69 ng/ml (colostrum), 3.14+/-0.72 ng/ml (the early stage of lactation) and 5.76+/-1.25 ng/ml (the late stage of lactation). The milk sIL1R2 concentrations were 1.83+/-0.47 ng/ml (colostrum), 0.73+/-0.22 ng/ml (the early stage of lactation) and 2.92+/-0.56 ng/ml (the late stage of lactation). The concentrations of IL1R2 in sera and milk were significantly higher at the late stage of lactation and colostrum than that of the early stage of lactation. The reduction rates of sIL1R2 levels from the colostrum to the early stage of lactation were 43.6% (serum) and 61% (whey). IL-1beta was detected in all the colostrum (995.9+/-346.6 ng/ml). Significant correlation was observed between the levels of colostral IL-1beta and IL1R2 (r=0.75).     

Variations with Breed,Age, Season,Yield, Stage of Lactation and Herd in the Concentration of Urea in Bulk Milk and Individual Cow’s Milk

The concentration of urea in the milk of 510 dairy cows in 10 herds was determined at regular intervals for a year. The herds contained approximately equal numbers of Swedish Red and White, and Swedish Holstein cows. The mean ± sd concentration in the samples from individual cows was 5.32 ± 1.13 mmol/1, and the mean concentration in bulk milk was 5.39 ± 0.96 mmol/1. These values indicated that on average the herds were fed too much protein relative to their intake of energy throughout the year. Herd factors had a strong influence on the milk urea concentration. The concentration was lower during the first month of lactation than later in the lactation, and lower when the cows were housed during the winter than when they were grazing. There was a weak positive relationship between the daily milk yield and urea concentration, particularly during late lactation, but there was no relationship with either breed or age. Bulk milk urea was a reliable guide to the average urea concentration of a herd.     

Chromium intake and urinary chromium excretion of trauma patients

Glucose metabolism is altered after trauma and those factors that affect glucose metabolism often affect chromium (Cr) metabolism and excretion. To ascertain whether urinary Cr excretion is affected by the elevated serum glucose and other factors associated with trauma, the serum glucose and urinary Cr and Creatinine (Cre) excretion of seven severely traumatized patients were determined. The Cr concentration of intravenous (IV) fluids administered was determined and approximate Cr intake calculated. For all patients, urinary Cr concentration was high in the initial sample collected within 24 h of admission (10.3 ± 2.5 ng/mL, mean ± SEM) and decreased significantly (P < 0.05) by 42 h (2.0 ±0.6 ng/mL). The mean urinary Cr concentration 42 h following admission was 10 times greater than the urinary Cr concentration of normal, healthy subjects (0.2 ± 0.02 ng/mL). There was no significant change in urinary Cre concentration within 42 h of admission, therefore the ratio of urinary Cr to Cre (ng Cr:mg Cre) also decreased. Serum glucose concentration was elevated at admission (170 ± 18 mg/dL, mean ± SD) and decreased to 145 ± 10 mg/dL by 48 h post-admission. The intravenous fluids, dextrose and NaCl, were the lowest in Cr of the samples tested, range 0.02 to 0.20 ng/mL; lactated Ringer’s solution, with or without dextrose, contained 10-20 times more Cr and plasma protein fraction contained approximately 32 ng/mL. The mean calculated Cr intake for the first 24 h postadmission was 37.1 µg/d, significantly greater (P < 0.01) than intake from 24 to 48 h (0.12 µg/d) and 48-72 h (1.63 µg/d). The IV intake of Cr varied for trauma patients depending on fluids required during treatment, but for all patients the relatively high IV Cr intake was rapidly excreted in the urine. These data demonstrate that urinary Cr concentration is elevated several-fold within 24 h of trauma and that Cr contents of intravenous fluids administered in the days immediately following injury vary dramatically. The effects of trauma alone on Cr excretion are difficult to assess because of the variable intake of Cr from IV fluids.     

Selenium Distribution in Camel Blood and Organs After Different Level of Dietary Selenium Supplementation

Eight young female camels shared in four groups of two 2 years received a basal diet enriched respectively with 0, 2, 4, and 8 mg selenium under sodium selenite form for 64 days. Feed intake was assessed daily; blood samples were taken on weekly basis. One camel from each group was killed at the end of the experiment. Se concentration in serum was increased significantly in the supplemented groups with an average of 176.3 ± 18.0 ng/mL in the control group, 382.7 ± 107.6 in the group receiving 2 mg Se, 519.8 ± 168.4 in the group receiving 4 mg Se, and 533.4 ± 158.6 in the group receiving 8 mg Se daily. For glutathione peroxidase (GSH-Px) activity, the control group (51.0 IU/g Hb) and the group receiving 2 mg (50.5 IU/g Hb) were significantly different than groups receiving 4 and 8 mg (respectively, 65.9 and 76.1 IU/g Hb). No significant variation occurred for vitamin E (mean, 0.56 ± 0.23 ng/mL). Significant correlation between serum Se and GSH-Px was reported. Kidney was the richest organ in selenium followed by lung, spleen, and liver, but the increase in supplemented groups was more marked in liver and kidney. The hair seemed to be the best indicator of selenium intake in camel.     

Factors affecting the selenium intake of people in transbaikalian Russia

The selenium concentration in foods grown and consumed and in plasma, red blood cells, and toenails of people living in the district of Chita in the transbaikalian part of Russia were studied in August 1991. Preliminary results from the area have suggested low selenium intakes and the possible occurrence of cardiomyopathy (Keshan disease) in the population. A low selenium concentration in foods grown locally was found: mean selenium concentration in wheat grains was 1, 5, and 28 μg/kg, respectively, in three villages studied, that of oats was beween 3–6 μg/kg, and of cow's milk 10–27 μg/kg dry matter. The selenium concentration of bread was considerably higher, between 87–337 μg/kg dry wt, presumably because wheat imported from the US had been used for baking. Occasional samples of pork, beef, and mutton contained between 32–318 μg selenium/kg dry wt. Low selenium concentrations were observed in samples of soil and river water. The mean plasma selenium concentration of 52 persons was 1.02 μmol/L, including 33 children and 19 adult subjects. The selenium concentrations in red blood cells and toenails were 1.95 μmol/L and 0.61 mg/kg, respectively. No symptoms of heart disease caused by selenium deficiency were observed. It is concluded that the selenium status of people was fairly good thanks to the contribution to dietary intake of imported wheat with a high selenium content. As the selenium concentration was very low in foods grown in the area, the selenium intake of the population will be reduced to a very low level if only locally produced foods are consumed.     

Associations among SPARC mRNA expression in adipose tissue,serum SPARC concentration and metabolic parameters in Korean women

Objective: Secreted protein acidic and rich in cysteine (SPARC) is expressed in most tissues and is also secreted by adipocytes. The associations of SPARC mRNA expression in visceral adipose tissue (VAT), subcutaneous abdominal adipose tissue (SAT), serum SPARC concentration, and metabolic parameters in Korean women are investigated. Design and Methods: This is a cross‐sectional study. Fifty‐eight women were recruited, of whom 15 women who underwent bariatric surgery for morbid obesity (BMI mean ± SD: 40.2±5.7 kg/m²), 16 who underwent metabolic surgery for type 2 diabetes (BMI: 28.9±4.5 kg/m²), and, as a control group, 27 who underwent gynecological surgery (BMI: 22.7±2.4 kg/m²). Anthropometric variables, metabolic parameters, SPARC mRNA expression in adipose tissue, and serum SPARC concentration were measured. Results: In all subjects, SPARC mRNA expression was significantly higher in SAT than in VAT. Serum SPARC concentrations (mean ± SE) in morbidly obese subjects, subjects with type 2 diabetes, and normal weight subjects were 267.3±40.2 ng/mL, 130.4±33.0 ng/mL, and 53.1±2.8 ng/mL, respectively. SPARC mRNA in SAT was significantly correlated with BMI, whereas SPARC mRNA in VAT was significantly correlated with BMI and VAT area. Serum SPARC concentration was significantly correlated with BMI, waist circumference, total adipose tissue area, and SAT area. After BMI adjustment, serum SPARC concentration was significantly correlated with fasting insulin concentration and HOMA‐IR score. Multivariate regression analysis showed that BMI and HOMA‐IR were independently associated with serum SPARC concentration. Conclusions: Serum SPARC concentration is significantly correlated with obesity indices and might be influenced by insulin resistance. These findings suggest that SPARC may contribute to the metabolic dysregulation associated with obesity in humans.     

Environmental effects of nationwide selenium fertilization in Finland

To study the possible pollution of natural waters by selenium added to agricultural fertilizers, water selenium concentrations were determined in lakes and ground water pools during the year 1992, when the enrichment of fertilizers by selenium had continued for 8 yr. Water samples were preconcentrated by evaporating, and selenium concentrations were analyzed fluorometrically using the dye 2,3-diaminonaphthalene after wet digestion. In lake water samples from 13 lakes, no significant correlations were found between selenium and pH, chlorophyll A, total nitrogen, or phosphorus. Agriculturally affected and nonaffected lakes had no differences in their selenium concentrations. In the lakes that were surrounded by cultivated fields mean water selenium was 83.4 ng/L (range: 75.2–93.4 ng/L,n=9). Correspondingly, in lakes situated in forests without agricultural surroundings, mean water selenium concentration was 76.5 ng/L (range: 51.2–110 ng/L,n=3). Only one lake in the close vicinity of a coal power plant had a high water selenium concentration (mean 272 ng/L). In ground water samples, there was a big variation in selenium levels between different pools, the levels varying between 33 and 260 ng/L. This variation may partly be explained by different selenium concentrations of the bedrock and sediments. However, simultaneous increase of total nitrogen, phosphorus, and selenium levels in consecutive samples from some ground water pools indicates leaching of selenium from the fertilizers into the ground water in certain areas.     

Selenium levels in infant milk formula

Twenty-four brands of commercial infant milk formula were collected and analysed for selenium by inductively coupled plasma spectrometry with the hydride t-system after an acid digestion procedure. The mean selenium concentration was 49.0 ± 11.55 g l, with a range from 26-68 g l, resulting in an adequate daily selenium intake for infants aged from zero to six months consuming 0.75 l milk daily as set by the US National Research Council in 1989.     

Macronutrient, mineral and trace element composition of breast milk from Japanese women

The aim of the study was to determine the concentrations of macronutrients and the mineral and trace element composition in maternal milk of Japanese women. We collected human milk samples from mothers living throughout Japan from December 1998 to September 1999, and defined as group A the 1197 samples among them that met the following conditions: breast milk of mothers who were under 40 years old, not in the habit of smoking and/or using vitamin supplements, and whose babies showed no symptoms of atopy and whose birth weights were 2.5 kg or more. We then analyzed their contents individually. We also analyzed the amino acid and free amino acid composition of the breast milk of pooled samples from various lactation stages. Large differences were found to exist among the contents of individual human milk samples. The mean contents of each component were as follows: energy, 66.3+/-13.3 kcal/100 mL; solid matter, 12.46+/-1.56 g/100 mL; ash, 0.19+/-0.06 g/100 mL; total nitrogen, 0.19+/-0.04 g/100 mL; lipids, 3.46+/-1.49 g/100 mL; carbohydrates, 7.58+/-0.77 g/100 mL; lactose, 6.44+/-0.49 g/100 mL; pH, 6.5+/-0.3; osmotic pressure, 299+/-14 mOsm/kg.H2O; chloride, 35.9+/-16.2 mg/100 mL; sodium, 13.5+/-8.7 mg/100 mL; magnesium, 2.7+/-0.9 mg/100 mL; phosphorus, 15.0+/-3.8 mg/100 mL; potassium, 47.0+/-12.1 mg/100 mL; calcium, 25.0+/-7.1 mg/100 mL; chromium, 5.9+/-4.7 microg/100 mL; manganese, 1.1+/-2.3 microg/100mL; iron, 119+/-251 microg/100 mL; copper, 35+/-21 microg/100 mL; zinc, 145+/-135 microg/100 mL; and selenium, 1.7+/-0.6 microg/100 mL. The content of each component varied greatly as the duration of lactation increased. In conclusion, it appears to be necessary to evaluate individual differences of human milk in order to perform valid research regarding infant formula.     

Effect of Different Selenium Supplementation Levels on Selenium Status in Camel

Twelve female camels divided into three groups received, after a 2-week adaptation period, an oral Se supplementation (0, 2, and 4 mg, respectively) under sodium selenite form for 3 months. Feed intake was assessed daily, blood samples and body weight were taken on a weekly basis, and feces and urine samples were collected every 2 weeks up to 1 month after the end of the supplementation period. The Se concentration in serum was increased significantly in supplemented groups. The maximum level was observed in the period of supplementation in the camel receiving 4 mg (492.5 ng/mL), which was fourfold higher than the value at the beginning of the trial (126 to 138.5 ng/mL according to the groups). The selenium concentration increased significantly in urine and feces but to a lesser extent. A similar trend was observed with glutathione-peroxidase (GSH-Px) values varying between 8.4 and 96.5 IU/g Hb. However, no difference occurred between the two groups receiving 2 or 4 mg Se at the supplementation period. Vitamin E (mean 1.13 +/- 0.61 microg/mL with range 0.27-3.09) did not change significantly. Significant correlations were reported between serum Se, GSH-Px, fecal, and urinary excretion or concentration.