Estimation of the bioavailability of zinc and calcium from human,cow's,goat, and sheep milk by an in vitro method

The availability of zinc and calcium from human, cow's, goat, and sheep milk is evaluated by an in vitro method that involves a simulated human gastrointestinal digestion followed by measurement of dialyzability of zinc and calcium. Zinc availability of milk showed the highest value for human milk (15.0%) and the lowest for sheep milk (1.0%), in both whole and skim milk. Calcium availability of the different types of milk did not differ significantly and ranged between 18 and 23%. No significant differences in availability between whole and skim milk were found for both elements, except for zinc in cow's milk.     

Supplementation of suckling rats with cow's milk induces hyperphagia and higher visceral adiposity in females at adulthood,but not in males

In humans, complementary feeding should be started after 6 months-old; the introduction of any food or water before this time is considered early weaning, which is associated with health problems in adulthood. Cow's milk is a common food introduced to children less than 6 months that has inadequate nutritional composition mainly due to a worse casein: whey protein ratio compared to human milk. We hypothesized that suckling rats fed with cow's milk, rich in bioactive peptides, develop further metabolic dysfunctions. From postnatal day (PN) 14 to 20, Wistar rat pups were divided into 3 groups: rat milk (RM) – pups received rat milk orally in a syringe; cow's milk (CM), pups received cow's milk; CM with high protein (CM-H), CM with twice protein amount of rat milk. Pups were killed on PN21 and PN180. At PN21, CM males had lower visceral fat mass compared with other groups. Serum corticosterone was higher in CM-H males, despite no change in glucocorticoid metabolism in liver and visceral fat. At PN180, CM and CM-H females had greater fat depots and hyperphagia, although no alteration in leptinemia and leptin signaling in hypothalamus. CM-H females had a trend of hypoinsulinemia and significant decrease in HOMA-β, suggesting lower insulin secretion. Males from CM-H group had only lower total body protein mass. CM males had hypercorticosteronemia associated with lower expression of 11βHDS1 in visceral fat. In conclusion, early introduction of cow's milk in neonate rats leads to gender-dependent differences in metabolic and endocrine parameters in the short- and long-term.     

Detection of Toxoplasma gondii DNA in milk of dairy cows from southern Brazil

Consumption of unpasteurized cow's milk may be a transmission route for some pathogenic microorganisms, but there is little information about the risk of Toxoplasma gondii infection. Blood and milk samples were collected in a paired and random fashion from 106 dairy cows and bulk-tank milk samples were also collected from each of the six farms, in southern Brazil. Serum anti-T.gondii antibodies (IgG) were detected by an indirect fluorescent antibody test (IFAT) with a cutoff point of 1:64. Nested PCR targeting the ITS1 was performed on milk samples to detect the Sarcocystidae family, confirmed to be T.gondii by Sanger sequencing. The occurrence of anti-T.gondii antibodies in the herds was 14.1%, (15/106) with seropositive cows in all herds. Antibody titers in positive samples ranged from 64 to 128. T.gondii DNA was detected in 2.8% (03/106) of the milk samples. The ITS1 sequences generated in this study were ON809793 - ON809794 and the sequencing revealed 98–100% identity with T. gondii DNA sequences deposited in GenBank. All cows PCR positive for T.gondii in milk were negative for IgG antibodies in serum, suggesting that naturally infected cows may shed T. gondii in milk in the acute phase of infection. The results of this study demonstrate that T. gondii DNA may be detected in raw cow's milk, so the potential risks of lactogenic infection should be considered. The presence of T. gondii DNA in milk does not confirm that the protozoa are viable and infective, and further investigations into the role of cow's milk in the epidemiology of toxoplasmosis are needed.     

Significance of Milk pH in Newborn Infants

Bottle-fed infants do not gain weight as rapidly as breast-fed babies during the first week of life. This weight lag can be corrected by the addition of a small amount of alkali (sodium bicarbonate or trometamol) to the feeds. The alkali corrects the acidity of cow''s milk which now assumes some of the properties of human breast milk. It has a bacteriostatic effect on specific Escherichia coli in vitro, and in infants it produces a stool with a preponderance of lactobacilli over E. coli organisms. When alkali is removed from the milk there is a decrease in the weight of an infant and the stools contain excessive numbers of E. coli bacteria.A pH-corrected milk appears to be more physiological than unaltered cow''s milk and may provide some protection against gastroenteritis in early life. Its bacteriostatic effect on specific E. coli may be of practical significance in feed preparations where terminal sterilization and refrigeration are not available. The study was conducted during the week after birth, and no conclusions are derived for older infants. The long-term effects of trometamol are unknown. No recommendation can be given for the addition of sodium bicarbonate to milks containing a higher content of sodium.     

Milk Consumption and Cardiovascular Risk Factors in Older Chinese: The Guangzhou Biobank Cohort Study

Background

Dairy products consumption is increasingly common globally. Most of the evidence concerning dairy products comes from observational studies in western populations which are inevitably open to confounding. To triangulate the evidence concerning dairy products, we examined the associations of whole cow''s milk consumption with cardiovascular risk factors in a non-Western setting with a different pattern of milk consumption and cardiovascular diseases from Western populations.

Methods

We used multivariable censored linear or logistic regression to examine cross-sectionally the adjusted associations of whole cow''s milk consumption (none (n = 14892), 1–3/week (n = 2689) and 3+/week (n = 2754)) with cardiovascular risk factors in Chinese (≥50 years) in the Guangzhou Biobank Cohort Study.

Results

Whole cow''s milk consumption was negatively associated with systolic blood pressure (3+/week compared to none −2.56 mmHg, 95% confidence interval (CI) −3.63 to −1.49), diastolic blood pressure (−1.32 mmHg, 95% CI −1.87 to −0.77) and triglycerides (−0.06 mmol/L, 95% CI −0.11 to −0.002), but was positively associated with HDL-cholesterol (0.02 mmol/L,95% CI 0.01 to 0.04) and fasting glucose (0.08 mmol/L, 95% CI 0.01 to 0.16) adjusted for age, sex, phase of study, socio-economic position, lifestyle (smoking, alcohol use and physical activity) and adiposity, but had no obvious association with LDL-cholesterol or the presence of diabetes.

Conclusions

Whole cow''s milk consumption had heterogeneous associations with cardiovascular risk factors. Higher whole cow''s milk consumption was associated with lower levels of specific cardiovascular risk factors which might suggest risk factor specific biological pathways with different relations to blood pressure and lipids than glucose.     

Dynamic cooling strategy based on individual animal response mitigated heat stress in dairy cows

Technological progress enables individual cow's temperatures to be measured in real time, using a bolus sensor inserted into the rumen (reticulorumen). However, current cooling systems often work at a constant schedule based on the ambient temperature and not on monitoring the animal itself. This study hypothesized that tailoring the cooling management to the cow's thermal reaction can mitigate heat stress. We propose a dynamic cooling system based on in vivo temperature sensors (boluses). Thus, cooling can be activated as needed and is thus most efficacious. A total of 30 lactating cows were randomly assigned to one of two groups; the groups received two different evaporative cooling regimes. A control group received cooling sessions on a preset time-based schedule, the method commonly used in farms; and an experimental group, which received the sensor-based (SB) cooling regime. Sensor-based was changed weekly according to the cow's reaction, as reflected in the changes in body temperatures from the previous week, as measured by reticulorumen boluses. The two treatment groups of cows had similar milk yields (44.7 kg/d), but those in the experimental group had higher milk fat (3.65 vs 3.43%), higher milk protein (3.23 vs 3.13%), higher energy corrected milk (ECM, 42.84 vs 41.48 kg/d), higher fat corrected milk 4%; (42.76 vs 41.34 kg/d), and shorter heat stress duration (5.03 vs 9.46 h/day) comparing to the control. Dry matter intake was higher in the experimental group. Daily visits to the feed trough were less frequent, with each visit lasting longer. The sensor-based cooling regime may be an effective tool to detect and ease heat stress in high-producing dairy cows during transitional seasons when heat load can become severe in arid and semi-arid zones.     

Body fat of British and Dutch infants.

The fatty acids in the body fat of 41 British and 37 Dutch infants between birth and 1 year were determined. At birth linoleic acid contributed 1-3% of the total fatty acids of the body fat in infants in both countries. By one month its proportion in the fat of the Dutch infants was about 25% and by four months 32-37%; in the fat of the British infants it was never more than 3%. In the Dutch infants this large increase in the linoleic acid percentage was accompanied by a fall in the percentage contribution of others, particularly the saturated acids myristic, palmitic, and stearic. Infants born preterm showed changes in their fat after birth similar to those in fullterm infants. The difference between the composition of the fat of the infants in the two countries is attributed to the nature of the fat in the milk they received. Until recently most British infants who are not breast-fed have been given milks based on cow''s milk with only minor modifications. For the past 10 years many Dutch infants have been given a milk in which all the cow''s milk fat has been replaced by maize oil. Dutch infants also had a lower concentration of cholesterol in their serum than British infants, which was not unexpected. The results show that the triglycerides in the adipose tissue are profoundly influenced by the nature of the fat in the diet.     

Daughter dearest: Sex‐biased calcium in mother's milk among rhesus macaques

Mother's milk provides building blocks necessary for infant development and growth postnatally. Minerals in milk are particularly important for infant skeletal development and may reflect maternal characteristics that are associated with the capacity to synthesize milk and sex‐specific developmental priorities of the infant. Using a large sample of mother–infant dyads assigned to the outdoor breeding colony at the California National Primate Research Center (N=104), we investigated the relationship of milk calcium (Ca) and phosphorus (P) concentrations and the ratio of Ca/P to maternal and infant characteristics and to other milk variables. Ca and P are largely associated with casein micelles, and as expected, both Ca and P were positively correlated with protein concentrations in milk. Neither Ca nor P concentrations were associated with maternal parity. Mothers rearing daughters tended to produce higher mean Ca concentration in milk, and consequently a higher Ca/P ratio, than did mothers rearing sons, even though protein concentration was not elevated. These results suggest that the Ca/P ratio in rhesus milk may have been under separate selective pressure from protein content to facilitate the accelerated rate of skeletal calcification that has been observed in female Macaca mulatta infants. Am J Phys Anthropol 151:144–150, 2013. © 2013 Wiley Periodicals, Inc.     

Profile of Nucleosides and Nucleotides in Donkey’s Milk

Nucleotides play a crucial role to cellular functions; they can be obtained from the diet or through the nucleotide salvage pathway, however, in particular situations (occurring mainly in newborns) the metabolic demand of nucleotides exceeds the capacity of their synthesis. These molecules, are receiving attention from a nutraceutical point of view because of their potential direct role in regulating metabolism and infant body condition. Donkey's milk may be considered a good replacer for cow's milk in feeding children with severe Ig-E mediated cow's milk protein allergy, due to its high similarity with human milk. In this study, the presence of cytidine, uridine, CMP, UMP, guanosine, and adenosine, involved in numerous biochemical and physiological activities, were detected for the first time through a RP-HPLC method.     

Prevalence of anemia among James Bay Cree infants of northern Quebec

BACKGROUND: Anemia is common among First Nation infants in Canada, often as a result of iron deficiency, which places them at risk for psychomotor impairment. Prevalence data are unavailable, and the risk factors are unknown. This study assessed the prevalence of anemia and associated risk factors among 9-month-old Cree infants in northern Quebec. METHODS: Between January 1995 and October 1998, 6 of 9 Cree villages in the James Bay region adopted a screening protocol for anemia in 9-month-old infants. Cross-sectional data were obtained from medical charts. The data for babies of very low birth weight and those with fever or infection were excluded. Among the 386 babies whose hemoglobin concentration was known, the type of milk consumed at the time of screening was known for 354. Associations between hemoglobin concentration and mean cell volume at 9 months, and milk type and weight gain since birth were analysed. RESULTS: The mean hemoglobin concentration of the 386 infants was 114.1 (standard deviation [SD] 10.6) g/L. The prevalence of anemia was 31.9% (95% confidence interval [CI] 27.2%-36.7%) with a hemoglobin cutoff value of 110 g/L, 17.6% 95% CI 13.9%-21.7%) with a cutoff value of 105 g/L, and 7.8% (95% CI 5.3%-10.9%) with a cutoff value of 100 g/L. Babies exclusively fed formula at 9 months had a higher mean hemoglobin concentration (118.5 [SD 9.9] g/L) than those exclusively fed breast milk (109.9 [SD 10.0] g/L), cow''s milk (112.5 [SD 10.1] g/L) or more than one type of milk (112.0 [SD 10.8] g/L) (p < 0.05). Compared with formula, the odds ratio (OR) for anemia was 7.9 (95% CI 3.4-18.2) for breast milk, 5.0 (95% CI 2.0-12.7) for cow''s milk and 5.2 (95% CI 1.9-14.6) for mixed milks. Infants fed formula and those fed cow''s milk had significantly greater weight gains since birth, by 724 g and 624 g respectively, than breast-fed infants (p < 0.05). When milk type was controlled for, weight gain since birth was significantly associated with the presence of microcytic erythrocytes (OR comparing highest tertile of weight gain to lowest tertile 2.9, 95% CI 1.2-6.6). INTERPRETATION: Iron-deficiency anemia is highly prevalent among James Bay Cree infants. Measures to increase iron intake are required.     

Availability of calcium from skim milk, calcium sulfate and calcium carbonate for bone mineralization in pigs

Dairy products provide abundant, accessible calcium for humans, while some calcium sulfate-rich mineral waters could provide appreciable amounts of calcium. But there is little evidence that this calcium is as available as milk calcium for making bone. The availability of calcium was studied by monitoring bone parameters in 2-month-old pigs fed restricted amounts of calcium (70% RDA) for 2.5 months. The 3 main (> or = 50% Ca intake) Ca sources were either CaCO3 or CaSO4 or skim milk powder (29% of the diet). The bones of the pigs fed the "milk" diet had higher (P < 0.01) ash contents, breaking strength and density (DEXA) than those of the two others groups, in which the bone values were similar. Thus, the calcium provided by a diet containing milk appears to ensure better bone mineralization than do calcium salts included in a non-milk diet. The calcium restriction may have enhanced some milk properties to stimulate calcium absorption in these young, rapidly growing pigs.     

Genetic parameters for milk mineral content and acidity predicted by mid-infrared spectroscopy in Holstein–Friesian cows

The aim of the present study was to estimate genetic parameters for calcium (Ca), phosphorus (P) and titratable acidity (TA) in bovine milk predicted by mid-IR spectroscopy (MIRS). Data consisted of 2458 Italian Holstein−Friesian cows sampled once in 220 farms. Information per sample on protein and fat percentage, pH and somatic cell count, as well as test-day milk yield, was also available. (Co)variance components were estimated using univariate and bivariate animal linear mixed models. Fixed effects considered in the analyses were herd of sampling, parity, lactation stage and a two-way interaction between parity and lactation stage; an additive genetic and residual term were included in the models as random effects. Estimates of heritability for Ca, P and TA were 0.10, 0.12 and 0.26, respectively. Positive moderate to strong phenotypic correlations (0.33 to 0.82) existed between Ca, P and TA, whereas phenotypic weak to moderate correlations (0.00 to 0.45) existed between these traits with both milk quality and yield. Moderate to strong genetic correlations (0.28 to 0.92) existed between Ca, P and TA, and between these predicted traits with both fat and protein percentage (0.35 to 0.91). The existence of heritable genetic variation for Ca, P and TA, coupled with the potential to predict these components for routine cow milk testing, imply that genetic gain in these traits is indeed possible.     

Procedure for simultaneous phenotyping of genetic variants in cow's milk by isoelectric focusing*

A method is described which allows the simultaneous separation of all polymorphic protein fractions in cow's milk in one single run. The separation could be achieved by isoelectric focusing in ultrathin-layer polyacrylamide gels. The method is especially suitable for screening purposes because it combines low costs, high resolution and short separation time.     

Diffusibility of selenate, selenite, seleno-methionine, and seleno-cystine during simulated gastrointestinal digestion

The present study was undertaken to evaluate the in vitro availability of chemically varying forms of selenium (Se), supplemented in cow's milk. Two inorganic (selenite and selenate) and two organic (seleno-methionine [Se-Met] and seleno-cystine [Se-Cys]) Se sources were evaluated. The in vitro availability was estimated by the diffusibility of Se during simulated gastrointestinal digestion. First, the diffusibility was compared after adding a constant amount of Se as either selenate, selenite, seleno-methionine, or Se-Cys in milk samples. Se-Met and selenate were found to be significantly more diffusible than selenocystine and selenite under the simulated gastrointestinal conditions. The tendency for superior in vitro availability of selenate and Se-Met compared to selenite and Se-Cys was confirmed for a supplementation range of 5–40 ng/g of Se. This study suggests that the high diffusibility of selenate and Se-Met in a simulated gastrointestinal environment may contribute to their high absorption in vivo.     

Comparison of minerals in milk of four species

• 1.1. Milk samples of 4 ml or more were obtained from guinea pigs (Cavia porcellus), dairy cattle (Bos taurus), horses (Equus caballus) and humans (Homo sapiens). The milks were analysed for minerals including calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na) by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES).
• 2.2. Calcium was approximately twice as concentrated in guinea pig milk as in cows' milk, which was twice as much as the level in mares' milk, and this, in turn, was twice as concentrated as human milk.
• 3.3. The ratio of Ca to P in guinea pig milk was 1.66:1, while it was 1.24:1 in cows' milk, 1.56:1 in mares' milk and 2.07:1 in human milk.
• 4.4. Potassium was the most abundant mineral in the milks of cows, mares and humans, but not in guinea pig milk, and was much higher in cows' milk than in others.
• 5.5. Sodium was highest in guinea pig milk with cows' milk being a close second.
• 6.6. Magnesium was one-tenth as concentrated as Ca.

     

Protective Effect of Administration of Skim Milk on Exogenous and Endogenous Infection in Mice

In order to minimize the denaturation of proteins in milk, normal cow's milk was pasteurized at 61 C for 20 min. The protective effects of the thus prepared skim milk (low-heat skim milk) on exogenous and endogenous infection were examined as compared with conventional skim milk which was pasteurized at 121 C for 2 sec. The antibody titers to Listeria monocytogenes and Escherichia coli of low-heat skim milk were almost equal to that of raw milk, while no antibody was detected in the conventional skim milk. When mice were given low-heat skim milk or conventional skim milk, the incidence of the translocation of orally inoculated Listeria monocytogenes to the spleen was lower in the low-heat skim milk group than that in the conventional skim milk group. The life span of 7 Gy X-ray irradiated mice given low-heat skim milk was significantly prolonged in comparison to that of mice given conventional skim milk. However, there were no differences in the number of bacteria in the feces or IgA production by Peyer's patch cells between the two groups. These results suggest that antibodies in low-heat skim milk, which still have reactivity to exogenous or indigenous bacteria, may contribute to the protective effects against bacterial infection.     

Recovery of Rauscher Leukemia Virus from Large Volumes of Seeded Cow's Milk and from Infected Murine Spleens

Rauscher murine leukemia virus was used as an indicator agent to develop a methodology for the extraction and concentration of a theoretical leukemia virus from bovine milk and tissues. The indicator virus was seeded into cow''s milk or was recovered from infected murine spleens. The tissue homogenates and the defatted milk were processed in a B-XVI rotor of a Spinco L-4 ultracentrifuge at a flow rate of 3 liters/hr. The efficiency of Rauscher virus recovery was greatest when the rotor was used without a gradient. A loss of between 0.6 and 0.7 log of total infectious virus, as determined by the spleen assay method, resulted when the seeded milk and murine spleens were processed. The procedures developed are presently being used in transmission experiments in an attempt to induce leukemia in the bovine.     

Case-control study of risk of dehydrating diarrhoea in infants in vulnerable period after full weaning.

OBJECTIVES: To investigate risk factors for dehydrating diarrhoea in infants, with special interest in the weaning period. DESIGN: Case-control study. SETTING: Metropolitan area of Porto Alegre, Brazil. SUBJECTS: Cases were 192 children aged 0-23 months hospitalised with acute diarrhoea and moderate to severe dehydration. Controls were 192 children matched for age and neighbourhood who did not have diarrhoea in the previous week. MAIN OUTCOME MEASURES: Associations between dehydrating diarrhoea and child''s age, type of milk consumed, time since breast feeding stopped, and breast feeding status. RESULTS: In infants aged < 12 months the risk of dehydrating diarrhoea was significantly higher in the first 9 months of life (P < 0.001), and in those aged 12-23 months the risk was again greater in younger children (12-17 months) (P = 0.03). The type of milk consumed before start of diarrhoea episode was strongly associated with dehydration independent of socioeconomic, environmental, maternal reproductive, demographic, and health services factors. Compared with infants exclusively breast fed, bottle fed infants were at higher risk (odds ratio (95% confidence interval) for cow''s milk 6.0 (1.8 to 19.8), for formula milk 6.9 (1.4 to 33.3)). Compared with those still breast feeding, children who stopped in the previous two months were more likely to develop dehydrating diarrhoea (odds ratio 8.4 (2.4 to 29.6)). This risk decreased with time since breast feeding stopped. CONCLUSION: These results confirm the protective effect of breast feeding and suggest there is a vulnerable period soon after breast feeding is stopped, which may be of relevance for developing preventive strategies.     

Influence of maternal dietary calcium levels on milk zinc, calcium and phosphorus contents and milk production in rats

The aim of this study was to analyze zinc (Zn), calcium (Ca) and phosphorus (P) contents in milk and the lactational performance in rats fed different Ca levels. Female Wistar rats were fed during pregnancy and lactation with experimental diets containing 20% protein and high (0.90%, HCa), normal (0.60%, NCa) or low (0.20%, LCa) Ca levels. Milk samples were collected after 15 days to determine the milk mineral composition. Pup weight was recorded from birth to weaning (litter size: 6-8 pups) to determine weight gain and calculate milk production. At delivery there were no significant differences in the body weight of the pups between the groups, but at day 15, the LCa group showed lower values than both NCa and HCa groups (p<0.05). The weight gain of the LCa group was significantly lower than of the HCa and NCa groups, between delivery and day 5 (p<0.05). This reduced rate of weight gain led to the LCa group reaching weaning weight later than the other groups. Milk production (g/pup/day) was significantly lower when dams were fed the LCa than the NCa and HCa diets (p<0.05). There were no significant differences among the groups in milk Ca, P and Zn levels and Ca/P ratio. The body mineral composition of the pups at birth did not differ between the groups; at weaning, however, both LCa and HCa groups had lower element contents than the NCa group (p<0.05). In conclusion, dams fed with a diet containing low Ca levels produced smaller volumes of milk and their pups reached weaning weights later than the other groups. As the milk mineral composition was not affected, it can be hypothesized that in dams fed low dietary Ca, the smaller milk yield might have been a way of maintaining milk quality. High Ca levels affected neither pregnancy outcome nor lactational performance.     

Null mutation in the gene encoding plasma membrane Ca2+-ATPase isoform 2 impairs calcium transport into milk

The means by which calcium is transported into the milk produced by mammary glands is a poorly understood process. One hypothesis is that it occurs during exocytosis of secretory products via the Golgi pathway, consistent with the observation that the SPCA1 Ca2+-ATPase, which is expressed in the Golgi, is induced in lactating mammary tissue. However, massive up-regulation of the PMCA2bw plasma membrane Ca2+-ATPase also occurs during lactation and is more strongly correlated with increases in milk calcium, suggesting that calcium may be secreted directly via this pump. To examine the physiological role of PMCA2bw in lactation we compared lactating PMCA2-null mice to heterozygous and wild-type mice. Relative expression levels of individual milk proteins were unaffected by genotype. However, milk from PMCA2-null mice had 60% less calcium than milk from heterozygous and wild-type mice, the total milk protein concentration was lower, and an indirect measure of milk production (litter weights) suggested that the PMCA2-null mice produce significantly less milk. In contrast, lactose was higher in milk from PMCA2-null mice during early lactation, but by day 12 of lactation there were no differences in milk lactose between the three genotypes. These data demonstrate that the activity of PMCA2bw is required for secretion of much of the calcium in milk. This major secretory function represents a novel biological role for the plasma membrane Ca2+-ATPases, which are generally regarded as premier regulators of intracellular Ca2+.