Zinc In Milk Research Articles

The effects of zinc supplementation on zinc, retinol and carotene levels in lactating Amazonian women

The effects of zinc supplementation on levels of zinc, retinol and carotene in serum and breast milk were investigated in a double blind controlled prospective study amongst 66 poor urban Amazonian mothers in 1981. The mothers predominantly breast-fed their infants for the first five months of life and took supplements from soon after birth. Milk retinol levels were already significantly higher in zinc supplemented (ZS) than non-zinc supplemented (NZS) mothers by one month post-partum, and by four months had risen significantly in the ZS mothers but fallen in NZS mothers. At four months post-partum, milk retinol levels of ZS mothers were near normal and double those of NZS mothers. The effect of zinc supplementation on these retinol levels was possibly associated with an increased absorption and utilization of dietary carotene, since milk carotene levels also increased in ZS mothers to levels three times those of NZS mothers at four months post-partum. This impact of zinc supplementation on maternal and breast milk vitamin A levels has not been shown previously and is of potential relevance where zinc and vitamin A deficiency are common.

Unconventional application of gold nanoclusters/Zn-MOF composite for fluorescence turn-on sensitive detection of zinc ion

Contrary to organic solvent-induced aggregation of Au nanoclusters (AuNCs), herein, we reported aggregation induced emission enhancement (AIEE) of AuNCs in an aqueous media through confinement of AuNCs by in situ formed Zn-MOF for detecting Zn2+. Glutathione capped AuNCs (GSH-AuNCs) was synthesized through reduction of Au3+ by glutathione. Zn2+ could significantly enhance the fluorescence of GSH-AuNCs upon addition of 2-methylimidazole, which was attributed to the formation of Zn-MOF. XRD and TEM were used to characterize the in situ formed Zn-MOF. Zn2+ induced aggregation was demonstrated by dynamic light scattering and TEM. The quantum yields (QYs) of AuNCs after aggregation induced by in situ formed Zn-MOF attained to 36.6%, which was nearly 9 times that of the sole AuNCs. On this basis, a fluorogenic sensor was reported for Zn2+ detection with a linear range from 12.3 nM to 24.6 μM and a detection limit of 6 nM (S/N = 3). The proposed sensor was successfully applied to assay the content of zinc in human serum, milk, water, and zinc sulfate syrup oral solution samples. The novel strategy proposed in this work may open a new window of interest in an unconventional application of gold nanoclusters/MOF nanoscale platform for metal ion detection and nutritional assessment of food.

The effects of a lipid-based nutrient supplement and antiretroviral therapy in a randomized controlled trial on iron, copper, and zinc in milk from HIV-infected Malawian mothers and associations with maternal and infant biomarkers.

We evaluated effects of antiretroviral (ARV) therapy and lipid‐based nutrient supplements (LNSs) on iron, copper, and zinc in milk of exclusively breastfeeding HIV‐infected Malawian mothers and their correlations with maternal and infant biomarkers. Human milk and blood at 2, 6, and 24 weeks post‐partum and blood during pregnancy (≤30 weeks gestation) were collected from 535 mothers/infant‐pairs in the Breastfeeding, Antiretrovirals, and Nutrition study. The participants received ARV, LNS, ARV and LNS, or no intervention from 0 to 28 weeks post‐partum. ARVs negatively affected copper and zinc milk concentrations, but only at 2 weeks, whereas LNS had no effect. Among all treatment groups, approximately 80–90% of copper and zinc and <50% of iron concentrations met the current adequate intake for infants at 2 weeks and only 1–19% at 24 weeks. Pregnancy haemoglobin was negatively correlated with milk iron at 2 and 6 weeks (r = −.18, p < .02 for both). The associations of the milk minerals with each other were the strongest correlations observed (r = .11–.47, p < .05 for all); none were found with infant biomarkers. At 2 weeks, moderately anaemic women produced milk higher in iron when ferritin was higher or TfR lower. At 6 weeks, higher maternal α‐1‐acid glycoprotein and C‐reactive protein were associated with higher milk minerals in mildly anaemic women. Infant TfR was lower when milk mineral concentrations were higher at 6 weeks and when mothers were moderately anaemic during pregnancy. ARV affects copper and zinc milk concentrations in early lactation, and maternal haemoglobin during pregnancy and lactation could influence the association between milk minerals and maternal and infant iron status and biomarkers of inflammation.

Determination of Microelements in Human Milk and Infant Formula Without Digestion by ICP-OES

The concentrations of zinc (Zn), iron (Fe) and copper (Cu) in both human milk and infant formula were determined using a new sample preparation method, by inductively coupled plasma - optical emission spectometry (ICP-OES) and flame atomic absorption spectrometry (FAAS). Human milk samples were diluted in ultrapure water. The infant formula of powder samples (suitable for an infant 1-6 months of age) and standard reference material (SRM-1849) were analyzed in parallel. The results have shown that FAAS method was more sensitive for Fe determination in human milk while ICP-OES was more sensitive for both Zn and Cu detection. The limit of quantification for both Zn and Cu was 5 μg L-1 and 10 μg L-1 for Fe and the recovery for Zn, Fe and Cu was ranged from 90% to 94%, 97% to 103% and 90% to 102%, respectively. Mean concentrations of Zn, Fe, and Cu in human milk samples were 5.35, 0.47 and 0.83 mg L-1, respectively while these values in infant formula were ranged from 3.52-4.75 mg L-1, 3.37-4.56 mg L-1 and 0.28-0.41 mg L-1, respectively. Despite the sample complexity, the proposed method using dilution of milk samples with water was simple, rapid, effective and accurate. ICP-OES was a better method for Zn determination while FAAS was a better method for Fe determination. In the case of Cu both methods were comparable.

Correlation between in vitro activity of milk leukocytes with milk constituents in high yielding crossbred cows

The relationship between the in vitro activity of milk leukocytes and milk constituents were studied in 48 high yielding clinically healthy crossbred cows. Milk somatic cell counts (SCC) was negatively correlated with milk lactose, total soid and solid not fat (SNF) content. Milk neutrophils were positively correlated with protein and Cu content and negatively correlated with fat content in milk. However milk lymphocytes were positively correlated with milk fat content and negatively correlated with protein content. Milk macrophages were positively correlated with milk SNF and total solid content. Milk lymphocyte blastogenic response (SI) was significantly positively correlated with milk protein, fat percentage and copper content and negatively correlated with milk lactose, milk total solids, SNF and zinc content. PI of milk neutrophils was positively correlated with zinc content and milk fat percentage and negatively correlated with milk total solid and SNF content. PI of milk macrophages was positively correlated with milk fat content. In the present investigation, immuno-potentiative role of various milk constituents such as milk protein, copper and zinc content on in vitro leukocyte activity was established.

The effect of the zinc concentration in breast milk on neonatal weight gain

The change in breast milk zinc (Zn) concentration in a feeding period during lactation may affect neonatal weight gain. The aim of this study was to determine how to change the Zn concentrations in breast milk during a feeding period in early and late lactation periods and identify the relationship between the differences in the Zn levels in breast milk during lactation and neonatal weight gain. Breast milk was collected in the early and late lactation periods with samples being obtained before (foremilk) and after (hindmilk) a feeding period. Then, we determined the Zn concentrations in the breast milk and measured the weight of the infants before and after the same feeding period. The study was composed of 37 newborns and their mothers. During the feeding period, the Zn concentrations in both the transitional and mature milk decreased significantly. During the lactation period, the Zn levels were markedly lower in only the hindmilk. The body weights of the infants both before and after feeding in the early lactation period were negatively correlated with the delta Zn concentration in the same period, but the delta body weights in the early lactation period were positively correlated with the Zn levels in the hindmilk in the same period. In addition, body weights before feeding in the late lactation period were also positively correlated with Zn levels in hindmilk in the early lactation period. This study suggests that the Zn concentrations in both the transitional and mature milk decreased, which suggests that changes in the Zn content of breast milk during lactation might play a role in the weight gain of healthy neonates.

THE EFFECT OF BLOOD AND MILK SERUM ZINC CONCENTRATION ON MILK SOMATIC CELL COUNT IN DAIRY COWS

The objective of this study was to evaluate the effect of blood and milk zinc concentration on somatic cell count and occurrence of subclinical mastitis cases. The study was performed on thirty Holstein cows approximate same body weight, ages 3 to 5 years, with equally milk production. Blood samples were taken after the morning milking from the caudal vein and milk from all four quarters was taken before morning milking. All samples of blood and milk were taken to determined zinc, using inductively coupled plasma mass spectrometry. 37.67% (11/30) cows have blood serum zinc concentration below 7µmol/l, and 63.33% or 19/30 cows have blood serum zinc concentration higher then 13µmol/l. Also 30% (9/30) cows have somatic cell count lower then 400.000/ml which indicate absence of subclinical mastitis, but 70% (21/30) cows have somatic cell count higher then 400.000/ml which indicate subclinical mastitis. Results indicate that cows with level of zinc in blood serum higher then 13 µmol/l have lower somatic cell count. Cows with lower zinc blood serum concentration then 7 µmol/l have high somatic cell count and high incidence of subclinical mastitis. According to results in this research there is no significant effect of milk serum zinc concentration on somatic cell count in dairy cows.

Minerals and Trace Elements in Human Breast Milk Are Associated with Guatemalan Infant Anthropometric Outcomes within the First 6 Months

Breast milk is the recommended source of nutrients for infant growth, but its adequacy to meet infants' mineral and trace element needs is unknown. We used breast-milk mineral and trace element concentrations of Guatemalan mothers at 3 lactation stages to estimate total daily intakes and to determine whether intakes were associated with early infant growth. In this cross-sectional study, breast-milk samples were collected from Mam-Mayan mothers during transitional (5-17 d, n = 56), early (18-46 d, n = 75), and established (4-6 mo, n = 103) lactation; z scores for weight (WAZ), length (LAZ), and head circumference (HCAZ) were measured. Concentrations of 11 minerals (calcium, potassium, magnesium, sodium, copper, iron, manganese, rubidium, selenium, strontium, and zinc) were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). WHO equations were used to calculate the estimated energy requirement, which was divided by the energy density of breast milk to estimate daily milk volume, and this number was multiplied by breast-milk mineral concentrations to estimate intakes. Principal component analyses identified clusters of minerals; principal components (PCs) were used in regression analyses for anthropometric outcomes. Estimated breast-milk intakes during established lactation were insufficient to compensate for the lower milk sodium, copper, manganese, and zinc concentrations in male infants and the lower sodium, iron and manganese concentrations in female infants. Estimated intakes of calcium, magnesium, potassium, sodium, and selenium were below the Institute of Medicine Adequate Intake for both sexes at all 3 stages of lactation. In early lactation, multiple linear regressions showed that PC1 (calcium, magnesium, potassium, rubidium, and strontium intakes) was positively associated with WAZ, LAZ, and HCAZ. In established lactation, the same PC with sodium added was positively associated with all 3 anthropometric outcomes; a second PC (PC2: zinc, copper, and selenium intakes) was associated with WAZ and LAZ but not HCAZ. Breast milk may be inadequate in selected minerals and trace elements where higher estimated intakes were associated with greater infant growth.

Zinc, lead, and cadmium levels in serum and milk of lactating women in Ibadan, Nigeria.

Zinc (Zn) is known to interact with lead (Pb) and cadmium (Cd) reversing their toxicity and reducing their concentrations. However, lactating women are at high risk of developing Zn deficiency, which may result in Pb and Cd intoxication or increased exposure of breast-fed infants to Pb and Cd from breast milk. The aim of this study was to determine Zn, Pb, and Cd concentrations and examine their relationship in serum and breast milk of lactating women in Ibadan, Nigeria. Ninety-two lactating women were recruited into this study. Anthropometric measurements were assessed by standard methods while serum and breast milk concentrations of Zn, Pb, and Cd were assessed by atomic absorption spectrophotometry. Data analyzed statistically by Student's t test, Pearson's correlation coefficient, and a multiple regression model were significant at p < 0.05. Zn deficiency was observed in 12 (17.1%) of lactating women. Breast milk levels of Zn, Pb, and Cd were significantly higher than their levels in serum, whereas the ratios Zn:Pb and Zn:Cd in milk were significantly less than serum ratios. Significant negative correlation was observed between milk Pb and serum Zn:Pb while milk Cd correlated positively with milk Zn. Significant positive correlations were observed between serum Zn and serum Zn:Pb, serum Zn and serum Zn:Cd, as well as serum Zn:Cd and serum Zn:Pb. Serum Cd and serum Zn were significantly negatively related. Significant negative correlations between serum Pb and serum Zn:Pb as well as milk Zn:Pb. Serum Cd and serum Zn:Pb as well as serum Zn:Cd correlated negatively. Milk Cd and Zn/Cd positively related with milk Pb while milk Zn was a negatively related with milk Pb in a multiple regression model ( R2 = 0.333; p = 0.023). Breast milk may be contaminated by toxic metals. However, Zn supplementation in deficient mothers may protect maternal and infant health.

Concentration of Zinc and Copper in Milk and Some Reproductive Aspects During Hot and Cold Seasons of Klebi Ewes Reared in South Egypt

Concentration of Zinc and Copper in Milk and Some Reproductive Aspects During Hot and Cold Seasons of Klebi Ewes Reared in South Egypt

Novel mutations in SLC30A2 involved in the pathogenesis of transient neonatal zinc deficiency

Infants are vulnerable to zinc deficiency. Thus, abnormally low breast milk zinc levels cause transient neonatal zinc deficiency (TNZD) in breast-fed infants. TNZD has been considered to be rare because of a paucity of citations in the published literature. However, recent studies of affected mothers identified four missense mutations in the solute carrier family 30 member 2 gene (SLC30A2), which encodes the zinc transporter, ZnT2. Genetic analyses of SLC30A2/ZnT2 in three Japanese mothers secreting low-zinc milk (whose infants developed TNZD) were performed. The effects of identified mutations were examined in a cell-based assay. Furthermore, 31 single-nucleotide polymorphisms (SNPs) in SLC30A2/ZnT2 were evaluated for their potential involvement in low-zinc levels in milk. Each mother had a different novel heterozygous mutation in SLC30A2/ZnT2. One mutation reduced splicing efficiency of the SLC30A2/ZnT2 transcript, and all ZnT2 mutants were defective in zinc transport and were unstable in cells. Moreover, four SNPs caused a significant loss of zinc-transport activity, similar to that in disease-causing ZnT2 mutants. Our results indicate that many SLC30A2/ZnT2 mutations cause or potentially cause TNZD. Genetic information concerning TNZD pathogenesis is limited, and our results suggest that the TNZD frequency may be higher than previously thought.

A Quantitative Analysis of Chromium and Zinc in Water and Raw Milk in Chittagong, Bangladesh

The concentration of selected heavy metals (chromium and zinc) was detected and estimated in water and raw milk collected from Chittagong City of Bangladesh. A total of 25 water samples and 20 raw milk samples were collected from different farms situated in 10 locations of Chittagong, Bangladesh. Chromium content in water was obtained in the range from 0.2 µg/L to 13 µg/L. The highest level of chromium content in water was 13.068 µg/L. The content of chromium in raw milk was obtained in the range from 2 µg/L to 17 µg/L. The highest level of chromium in milk was 17.062 µg/L. Chromium concentrations in water and milk were below the maximum allowed limit. The concentration of zinc in water was in the range from 0.01 mg/L to 1 mg/L. The highest level of zinc in water was 1.024 mg/L. The concentration of zinc in raw milk was in the range from 0.6 mg/L to 0.9 mg/L. The highest concentration of zinc in water was 1.024 mg/L which is around the toxicological guidance value of zinc.

Association of Maternal Diet With Zinc, Copper, and Iron Concentrations in Transitional Human Milk Produced by Korean Mothers.

The aims of this study were to evaluate zinc, copper, and iron concentrations in the transitory milk of Korean lactating mothers and to investigate the relationship between these concentrations and maternal diet. Human milk samples were collected between 5 and 15 days postpartum from 96 healthy, lactating mothers in postpartum care centers in Seoul, Korea. Dietary intake during lactation was determined based on a 3-day dietary record. The mean zinc, copper, and iron concentrations in the human milk samples collected were 3.88 ± 1.74 mg/L, 0.69 ± 0.25 mg/L, and 5.85 ± 8.53 mg/L, respectively. The mothers who consumed alcoholic beverages during pregnancy had tended to have lower concentrations of zinc and copper, as well as significantly lower concentrations of iron, in their milk (p < 0.047). In contrast, the mothers who took daily supplements had much higher iron concentrations in their milk (p = 0.002). Dietary intakes of zinc, copper, and iron during lactation did not affect the concentrations of zinc, copper, and iron in the milk samples analyzed. Intakes of vitamin C, selenium, and iodine were associated with the concentration of copper in the milk samples analyzed, and consumption of food categorized as 'meat and meat products' was positively associated with the concentration of zinc. Consumption of rice was the top contributor to the concentrations of all three minerals. In conclusion, associations between maternal diet and nutrient concentrations in transitory human milk can provide useful information, particularly in regard to infant growth.

Essential Role for Zinc Transporter 2 (ZnT2)-mediated Zinc Transport in Mammary Gland Development and Function during Lactation

The zinc transporter ZnT2 (SLC30A2) imports zinc into vesicles in secreting mammary epithelial cells (MECs) and is critical for zinc efflux into milk during lactation. Recent studies show that ZnT2 also imports zinc into mitochondria and is expressed in the non-lactating mammary gland and non-secreting MECs, highlighting the importance of ZnT2 in general mammary gland biology. In this study we used nulliparous and lactating ZnT2-null mice and characterized the consequences on mammary gland development, function during lactation, and milk composition. We found that ZnT2 was primarily expressed in MECs and to a limited extent in macrophages in the nulliparous mammary gland and loss of ZnT2 impaired mammary expansion during development. Secondly, we found that lactating ZnT2-null mice had substantial defects in mammary gland architecture and MEC function during secretion, including fewer, condensed and disorganized alveoli, impaired Stat5 activation, and unpolarized MECs. Loss of ZnT2 led to reduced milk volume and milk containing less protein, fat, and lactose compared with wild-type littermates, implicating ZnT2 in the regulation of mammary differentiation and optimal milk production during lactation. Together, these results demonstrate that ZnT2-mediated zinc transport is critical for mammary gland function, suggesting that defects in ZnT2 not only reduce milk zinc concentration but may compromise breast health and increase the risk for lactation insufficiency in lactating women.

Zinc and Copper Concentrations in Breast Milk During the First Nine Months of Lactation: A Longitudinal Study

A wide variation in the composition of breast milk has been reported from various countries. The aim of this study was to evaluate zinc (Zn) and copper (Cu) concentrations in the breast milk of lactating mothers as a function of lactation time and the relationship between these concentrations and the characteristics of mother–infant dyads. Mother–infant dyads were recruited immediately at the second week postpartum. Inclusion criteria were as follows: (1) gestational age ≥37 weeks; (2) birth weight ≥2500 g; and (3) no chronic illness in the infant or mother. Anthropometric measurements of …

A pilot study of synbiotic supplementation on breast milk mineral concentrations and growth of exclusively breast fed infants

Despite the crucial role of breast milk mineral contents for health and growth of the infants, they decrease with the duration of lactation. So, this pilot study aimed to determine the effects of synbiotic supplementation on breast milk mineral composition and infants’ growth. In this pilot, randomized, double-blind, placebo-controlled trial, 57 lactating mothers were randomly divided into two groups to receive a daily supplement of synbiotic (n=30) or a placebo (n=27) for 30 days. Breast milk zinc, copper, Iron, magnesium and, calcium concentrations were determined by flame atomic absorption spectrometry. Weight for age Z-score (WAZ) and height for age Z-score (HAZ) were assessed for infants. Dietary intake was collected from lactating women using the 24-h recall method. Data analyses were carried out using nutritionist IV, Epi Info and SPSS soft wares. Synbiotic supplementation led to an insignificant increase of the mean breast milk levels of zinc (from 2.44±0.65 to 2.55±0.55mgL−1), copper (from 0.35±0.24 to 0.40±0.26mgL−1), iron (from 0.28±0.42 to 0.31±0.38mgL−1), magnesium (from 17.14±1.35 to 17.17±1.09mgL−1), and calcium (from 189±25.3 to 189.9±21.7mgL−1); whilst in the placebo group, these variables decreased significantly (P=0.001). The observed changes between two groups were statistically significant (P<0.05). Although WAZ and HAZ of infants increased slightly in the supplemented group (from 1.19±0.79 to 1.20±0.69 and 0.36±0.86 to 0.37±0.85 respectively), these two parameters decreased in the placebo group which was significant only for WAZ (P=0.01). Moreover, no significant association was found between mineral intake and breast milk mineral contents. It seems, synbiotic supplementation may have positive effects on breast milk mineral contents.

Effect of Vitamin E and Zinc Supplementation on Milk Yield, Milk Composition, and Udder Health in Sahiwal Cows

Present study was conducted to assess the effect of vitamin E and zinc supplementation on milk yield, milk composition and udder health in Sahiwal cows. Thirty-two pregnant Sahiwal cows were selected at sixty days prepartum and divided into four groups namely control, T1, T2 and T3 of eight cows each. Cows under T1 were supplemented with Zn (60 ppm), while those under T2 were supplemented with vitamin E (1000IU); the cows under T3 were supplemented with a combination of vitamin E (1000 IU) and zinc (60 ppm) during day 60 prepartum to day 90 postpartum. After calving, milk yield of the experimental animals was recorded daily up to 120 days of lactation. Milk samples were collected fortnightly from all cows of all four groups for the estimation of milk composition (fat, protein, lactose and solid not fat), somatic cell count (SCC), and percentage of subclinical mastitis, vitamin E, and zinc. Dry matter intake (DMI), milk yield, and fat corrected milk were observed higher (P<0.05) in T3 than control, T1 and T2 groups. Milk composition did not differ significantly among the four groups. Somatic cell count and percentage of subclinical mastitis was significantly (P<0.05) lower in T3 in comparison to control, T1 and T2 groups. Milk vitamin E was higher (P<0.05) in vitamin E supplemented groups (T2 and T3) than non-supplemented groups (control and T1). Milk zinc was found higher (P<0.05) in zinc supplemented groups (T1 and T3) than non-supplemented groups (control and T2). In the present study, vitamin E and zinc supplementation to Sahiwal cows increased the milk yield, vitamin E, and zinc contents in milk, and reduced the somatic cell count and percentage of subclinical mastitis.

Maternal zinc status is associated with breast milk zinc concentration and zinc status in breastfed infants aged 4-6 months.

Breast milk provides adequate nutrients during the first 6 months of life. However, there are some reports of zinc deficiency in breastfed infants. This study was conducted to determine the prevalence of zinc deficiency in infants aged 4-6 months and the associated factors. Healthy infants aged 4-6 months and their mothers were enrolled. They were classified by feeding types as breastfed (BF), formula-fed (FF), and mixed groups (MF). Data collection included demographic data, perinatal data, given diets, and anthropometric measurement. Blood from infants and lactating mothers, and breast milk samples were collected to assess plasma and breast milk zinc concentrations. From 158 infants, the prevalence of zinc deficiency (plasma level below 10.7 mol/L) was 7.6%, and according to feeding groups 14.9%, 5.3%, and 2.9% in the BF, the FF, and the MF groups, respectively. Breastfed infants with zinc deficiency had significantly lower maternal zinc concentrations compared with those without zinc deficiency. There was a higher proportion of maternal zinc deficiency in zinc-deficient infants than those without zinc deficiency (66.7% vs 16.2%, p=0.02). There was a positive correlation between zinc concentrations in breast milk and plasma zinc concentrations of infants (r=0.62, p=0.01) and plasma zinc concentrations of lactating mothers (r=0.56, p=0.016). Using the regression analysis, infant zinc status was associated with maternal plasma zinc concentrations among breastfed infants. The results of this study suggest that breastfed infants aged 4-6 months may have a risk of zinc deficiency and that risk is associated with maternal zinc status and breast milk zinc concentrations.

Effect of Feeding Seaweed as Mineral Source on Mineral Metabolism, Blood and Milk Mineral Profile in Cows

Seaweeds are rich in minerals. The present experiment was designed to see the effect of replacing minerals and a part of concentrate mixture (CM) by seaweed in cows. Sahiwal cows (n = 12) were randomly blocked into three equal groups on the basis of milk yield (mean 8.39 L/day) and parity. Animals were offered concentrate mixtures along with wheat straw and green oat as total mixed ration (CM and roughages as 50:50; green oat and wheat straw as 60:40) for 126 days. Control animals (T1) were offered CM without mineral and salt premix; group T2 animals had 2 % mineral premix and 1 % salt in their CM while seaweed group (T3) had 20 % seaweed in their CM without additional mineral and salt. The results revealed no significant changes in plasma mineral profile and mineral metabolism except that of copper and zinc (P < 0.01) in the groups without mineral and salt (T1, T3). Milk mineral profile remained similar in all treatment groups except milk phosphorus, copper and zinc which were highest in T2 followed by T1 and T3. A clear trend was reflected in mineral metabolism and its status in blood and milk corresponding to that of dietary mineral composition. Thus, incorporation of brown seaweed in the diet of lactating Sahiwal cows (20 % in concentrate mixture) did not affect mineral metabolism and blood–milk mineral profiles, except copper and zinc; which need to be additionally supplemented in the diet.

Heavy metals and trace elements levels in milk and milk products

Milk and dairy products are an important food in the human diet. The present investigation was carried out to determine concentrations of lead, cadmium, zinc, copper and iron in milk and dairy products and evaluate the potential health risks of metals to humans via consumption of milk and dairy products. A total of 77 samples of milk and dairy products (22 raw milk, 20 kareish cheese, 21 butter and 14 rice pudding) were collected from farms, individual farmers and dairy shops in Beni-Suef governorate, Egypt. Pb, Cd, Zn, Cu and Fe concentrations in milk and dairy products ranged from 0.044–0.751, 0.008–0.179, 0.888–18.316, 0.002–1.692 and 1.3208–45.6198 ppm respectively. Pb concentration in all samples exceeded the maximum permissible limit (0.02 mg/kg) established by codex standard. Pd and Cd intake through milk and dairy products consumption were 1.27 and 0.33 μg/kg bw/day, which represent 35.3 and 39.8 % of the tolerable daily intake. Dairy products are poor sources of iron, copper and zinc, and milk contributes little to the total iron and zinc intake. Target hazard quotient values of less than 1 indicate a relative absence of health risks associated with the consumption of milk and dairy products.