Calcium-supplemented goat milk does not interfere with iron absorption in rats with anaemia induced by dietary iron depletion

The short-term effects of Ca-supplemented goat or cow milk on the nutritive utilization of Fe were evaluated in a metabolic balance study of rats with nutritional ferropenic anaemia (NFA). Control and Fe-deficient rats were fed for 14 d with goat or cow milk diets containing high-Ca content (10,000 mg/kg diet). The consumption of diets containing high levels of Ca for 14 d had no adverse effects on Fe absorption when the goat milk-based diet was provided, whereas for the cow milk-based diet, there was a significant fall in the apparent digestibility coefficient (ADC) of Fe. Moreover, the ADC and Fe retention/intake ratio (R/I) were higher in the anaemic rats fed the goat milk diet than among those fed the cow milk diet. These results suggest that despite a high dietary Ca content, goat milk minimizes Ca–Fe interactions and has no adverse effects on Fe absorption in rats with NFA.     

Effect of calcium-supplemented goat or cow milk on zinc status in rats with nutritional ferropenic anaemia

The effects of goat- or cow-milk-based diets, whether normal or supplemented with calcium (5 or 10 g kg^?1 Ca, respectively), on the nutritive utilization of Zn and its deposition in organs, were evaluated in rats with and without nutritional ferropenic anaemia (NFA). The digestive and metabolic utilization of Zn in anaemic and control groups was higher for rats on the goat milk diet than those on the cow milk diet. The most noteworthy result is that Ca supplementation in the diet improved Zn metabolism in all experimental groups, but especially in anaemic rats fed the goat milk diet. This fact is reflected in the higher levels of Zn deposition found with the goat milk diet. It appears that goat milk, especially when supplemented with Ca, had beneficial effects on nutritive utilization of Zn and Zn deposition in target organs in both control rats and, especially, rats with NFA.     

Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency

The effect of goat or cow milk-based diets, with either normal Fe content or an Fe overload, on bone turnover and the mineralization process was studied in control and anemic rats during chronic Fe repletion. One hundred eighty male Wistar rats were studied during a pre-experimental period of 40 d in which they were randomly divided into 2 groups, a control group receiving the AIN-93G diet with normal Fe content (45 mg/kg of diet) and the Fe-deficient group receiving the AIN-93G diet with low Fe content (5 mg/kg of diet) for 40 d. After the pre-experimental period, the rats were fed for 10, 30, or 50 d with goat or cow milk-based diets with a normal Fe content (45 mg/kg of diet) or an Fe overload (450 mg/kg of diet). In anemic rats, goat milk with normal Fe content increased levels of the biomarker of bone formation N-terminal propeptides of type I procollagen and diminished parathyroid hormone levels after only 10 d of supplying this diet, indicating the beginning of restoration of the bone demineralization induced by the anemia, which was not observed with cow milk. After 30 d of supplying the milk-based diets with normal Fe content or an Fe overload, biomarkers of bone formation and bone resorption were not different between control and anemic rats, indicating that the bone demineralization induced by the Fe-deficiency anemia had recovered, although the process of stabilization of bone turnover began earlier in the animals fed goat milk. In addition, a higher Ca deposit was observed in femur, which positively affects bone mineralization, as well as an increase of Fe in sternum, which indicates that the hematopoietic process essentially recovered earlier on the goat milk diet compared with the cow milk diet.     

Goat milk consumption protects DNA against damage induced by chronic iron overload in anaemic rats

The effect of cow or goat milk-based diets, either normal or Fe-overloaded, on DNA stability was studied in control and anaemic rats for 30 or 50 days of chronic Fe repletion. DNA damage was assessed using the alkaline comet assay. Background DNA damage in lymphocytes of peripheral blood was much lower in control and anaemic rats, given the normal or Fe-overloaded goat milk-based diet after 30 and 50 days versus cow milk-based diet. Chronic Fe-overload had no adverse effect on DNA stability in control and anaemic fed the goat milk-based diet versus the same diet with normal-Fe content at the end of the study. The quality of goat milk fat, together with the high levels of bioavailable Mg and Zn may be responsible for its protective effect on DNA of peripheral blood lymphocytes under the different experimental conditions, even during chronic Fe-overload.     

Calcium‐enriched goat milk,in comparison with similarly enriched cow milk,favours magnesium bioavailability in rats with nutritional ferropenic anaemia

BACKGROUND: The effects of dietary consumption of goat or cow milk, normal or enriched with calcium (Ca), on magnesium (Mg) bioavailability was evaluated in rats with nutritional ferropenic anaemia. Control and iron‐deficient rats were fed for 14 days with iron‐normal diets containing either normal (5000 mg kg^?1 diet) or high (10 000 mg kg^?1 diet) Ca content. RESULTS: The results shown that the goat milk diet gave the best results for digestive and metabolic utilization of Mg, both among the anaemic and the control group, with respect to the cow milk and standard diets. The most noteworthy result of Ca enrichment on the nutritive utilization of Mg is that it is less prejudicial in this respect when supplemented via goat milk than with cow milk or the standard diet. CONCLUSION: The results demonstrate the beneficial effects of the goat milk, normal or with double Ca, on the nutritional utilization of Mg; therefore the consumption of this type of milk for people with nutritional ferropenic anaemia can be recommended. Copyright © 2007 Society of Chemical Industry     

Beneficial effect of goat milk on nutritive utilization of iron and copper in malabsorption syndrome

The search for diets that improve the digestive and metabolic use of iron and copper in malabsorption syndrome led us to study goat milk for particular nutritional characteristics and compare it with cow milk, which is usually supplied. We studied the metabolism of iron and copper in transected rats (control) and in resected rats (resection of 50% of the distal small intestine). The diets used were the standard diet recommended by the American Institute of Nutrition and diets based on goat or cow milk. Intestinal resection reduced the apparent digestibility coefficient (ADC) of iron in the three diets tested. In the transected and resected rats, the ADC of iron was highest with the goat milk diet, followed by the standard diet and lowest with the cow milk diet. The ADC of copper was not affected by intestinal resection in the animals fed the goat milk diet, and was higher than that in the two groups of animals fed the other diets. Intestinal resection reduced the ADC of copper with the standard diet and the cow milk diet. When both groups of animals were fed the goat milk diet, the deposit of iron in the organs was greater than with those fed the cow milk diet and similar to that in those animals given the standard diet. The copper content in the kidneys was lower in the resected than in the transected animals, except in the case of those fed the goat milk diet, in which it was similar to that of the control (transected) rats. This study shows the beneficial effect of goat milk, with respect to cow milk, on the metabolism of iron and copper in control rats, especially those with malabsorption syndrome.     

Goat milk consumption modulates liver divalent metal transporter 1 (DMT1) expression and serum hepcidin during Fe repletion in Fe-deficiency anemia

Iron deficiency is the most prevalent micronutrient deficiency worldwide. In spite of the crucial role of hepatocyte divalent metal transporter 1 (DMT1) and hepcidin in Fe metabolism, to date, no studies have directly tested the role of these proteins in liver Fe metabolism during Fe repletion after induced Fe-deficiency anemia. Therefore, the aim of the current study was to assess the effect of goat or cow milk-based diets on Fe metabolism in one of the main body storage organs, the liver, during the course of Fe repletion with goat or cow milk-based diets in anemic rats. Animals were placed on a preexperimental period of 40 d, a control group receiving a normal-Fe diet and the Fe-deficient group receiving a low-Fe diet (5 mg of Fe/kg of diet). Rats were fed for 30 d with goat or cow milk-based diets with normal Fe content (45 mg of Fe/kg of diet). The hematological parameters, serum hepcidin, hepatosomatic index, liver Fe content, and liver DMT1 expression were determined. During the recovery of the anemia with milk-based diets, the restoration of liver Fe content and hematological parameters, especially with goat milk, increased the red blood cell count, favoring the oxygen supply and weight gain. Moreover, goat milk consumption potentiates liver DMT1 expression, enhancing Fe metabolism and storage. In addition, the increase in serum hepcidin in anemic rats observed in the current study also explains and supports the higher liver Fe content after supplying goat milk, because it blocks the liberation of Fe from hepatocytes, increasing its storage in liver.     

Dietary goat milk improves iron bioavailability in rats with induced ferropenic anaemia in comparison with cow milk

Using rats with induced iron (Fe)-deficiency anaemia, this study investigated the effects of diets based on goat milk (GM) or cow milk (CM) lyophilates on the nutritive utilization of Fe, its deposit in target organs and haematic parameters involved in Fe metabolism. GM improved Fe metabolism, especially in Fe-deficient rats, leading to a higher Fe content in the spleen, liver, sternum and femur in comparison with CM. After feeding the rats for 2 weeks with the different diets, the anaemia had decreased, especially with GM, as assessed by higher haemoglobin regeneration efficiency (HRE), serum Fe, red blood cells (RBC) and packed cellular volume (PCV) levels and lower platelet count. We conclude that dietary GM improves Fe bioavailability in both control and anaemic rats, increasing Fe deposits in target organs and favouring the recovery of haematological parameters after ferropenic nutritional anaemia.     

Effect of dietary inclusion of goat milk on the bioavailability of zinc and selenium in rats

The effects of dietary inclusion of freeze-dried goat and cow milk on the utilization of zinc and selenium, and on the metabolic fate of zinc, were studied in transected (control) and resected rats (resection of 50% of the distal small intestine). Intestinal resection reduced the apparent digestibility coefficient and zinc retention in the cow milk diet, whereas these biological indices were similar in transected (control) and resected rats with standard (without milk) and goat milk diets. The apparent digestibility coefficient and retention of selenium were not affected by intestinal resection in the animals fed with the three diets studied. In transected (control) and resected rats, the apparent digestibility coefficient and retention of zinc and selenium were higher for the goat milk diet than for the other two diets. Zinc deposits in the organs, expressed as microg/g dry weight were in order of decreasing concentrations: femur, testes, sternum, liver, kidney, heart, spleen, longissimus dorsi muscle and brain. Deposits were greatest with the goat milk diet, followed by the standard diet and were lowest for the rats given the cow milk diet, both for transected (control) and resected animals. We conclude that consumption of the goat milk diet produces a greater bioavailability of zinc and selenium and a greater deposit of zinc in key organs, for both the transected (control) and the resected rats, with respect to the standard diet and the cow milk diet.     

Bioavailability of iron in goat milk compared with cow milk fed to anemic rats

Bioavailabilities of iron from dehydrated whole and skim goat milk were investigated using iron-deficient rats. Hemoglobin regeneration efficiencies were determined as the percent conversion of dietary iron into hemoglobin. The respective hemoglobin regeneration efficiencies for groups fed whole goat milk, whole cow milk, skim goat milk, and skim cow milk were 50.6, 13.1, 26.0, and 13.0%, indicating that iron bioavailability of goat milk was greater than cow milk. However, rats fed each milk had negative net increases in hemoglobin concentrations, implying that the iron contents of each milk were not adequate. For animals consuming whole goat milk supplemented with ferrous sulfate, the slope relating hemoglobin iron gained versus iron intake was .95. Respective bioavailabilities relative to ferrous sulfate were 54, 14, 28, and 14% for the four sources of milk. Iron bioavailability of goat milk is superior to cow milk when fed to anemic rats.     

Study of nutritive utilization of protein and magnesium in rats with resection of the distal small intestine. Beneficial effect of goat milk

The search for diets to improve the nutritive utilization of protein and magnesium in malabsorption syndrome led us to study goat milk, because of its particular nutritional characteristics, and to compare it with cow milk, which is most commonly consumed. We studied the nutritive utilization of protein and magnesium in transected rats (control) and in rats with resection of 50% of the distal small intestine. The diets used were the standard diet recommended by the American Institute of Nutrition and diets based on lyophilized goat or cow milk. The consumption of goat milk produces better protein efficiency ratio and food conversion efficiency values, particularly in rats with intestinal resection, together with a higher nutritive utilization of protein. Magnesium apparent digestibility coefficient is not modified by intestinal resection in rats fed with goat milk-based diet, on the contrary to the standard and cow milk diets. Magnesium apparent digestibility coefficient is greater for the goat milk group, which is reflected in the greater quantity of this mineral stored in bone. These results demonstrate the beneficial effect of goat milk on the nutritive utilization of protein and on magnesium bioavailability, especially in animals with resection of the distal small intestine.     

Digestive utilization of goat and cow milk fat in malabsorption syndrome.

We studied the effects of goat and cow milk fat on the digestive utilization of this nutrient and on some of the biochemical parameters that are related to the metabolisim of lipids, using rats with a resection of 50% of the distal small intestine and control animals (transected). The fat content in all the diets was 10% but the lipid quality was varied: the standard diet was based on olive oil, while the other two diets included fat obtained from lyophilized goat milk and cow milk, respectively. The digestive utilization of the fat was lower in the resected animals than in the transected ones for all three diets studied. In both resected and transected animals. the apparent digestibility coefficient (ADC) of the fat was greater with the standard diet (olive oil) than with diets whose fat content was provided by goat or cow milk. The digestive utilization of the fat was greater in the transected and resected rats receiving a diet of goat's milk (rich in medium-chain triglycerides) than those given a cow-milk-based diet and more closely approached the values obtained for olive oil. The consumption of goat milk reduced levels of cholesterol while levels of triglycerides, HDL, GOT and GPT remained with in the normal ranges, for both transected and resected animals. The advantageous effect of goat milk on the metabolisim of lipids with respect to cow milk suggests that the former should be included in the diet in eases of malabsorption snydrome.     

Impact of goat milk powdered formulations on mineral absorption,peak bone mass and bone loss due to ovariectomy in rats

BACKGROUND: Goat milk is recognised as nutritious, with benefits to growth and skeletal development. The initial aim of this study was to investigate the effect of three different goat milk formulae—a whole milk, a skim milk and a goat milk growing‐up formula fortified with pre‐ and probiotics (Formula 1)—on mineral absorption and retention in rats. The effect of long‐term intake of the fortified formula diet on peak bone mass and post‐ovariectomy bone loss in rats was then investigated in a follow‐up study and was assessed by bone density dual‐energy X‐ray absorptiometry and biomechanical testing of bone ex vivo. RESULTS: Goat whole milk and fortified milk formulations improved calcium and phosphorus absorption and retention. Body composition analysis showed that rats fed the fortified diet had higher body calcium and phosphorus content. The fortified diet was then tested in a long‐term feeding trial. Rats fed the fortified diet from weaning had a higher peak bone mass than rats fed a soy protein control diet. Bone mineral content (BMC) and density (BMD) of the lumbar spine were higher in rats fed the fortified diet. After ovariectomy, all rats lost bone mass, but rats fed the fortified diet maintained significantly higher BMD and BMC values throughout the trial, though still lower than those of non‐ovariectomised control rats. The fortified diet increased bone strength. CONCLUSION: Goat milk specific nutrients supported by pre‐ and probiotics in Formula 1 may improve mineral status during growth and support attainment of peak bone mass. Copyright © 2008 Society of Chemical Industry     

True ileal amino acid digestibility of goat and cow milk infant formulas

Goat milk is used as an alternative to cow milk for the production of infant formulas. However, little is known about the protein quality and, specifically, about the digestible AA pattern of goat milk formulas compared with their cow milk counterparts. In this study, the true ileal AA digestibility of a goat milk infant formula was compared with a premium cow milk infant formula. The 3-wk-old piglet was used as a model for the 3-mo-old infant. Both milk formulas were prepared as described by the manufacturer, with titanium dioxide added as an indigestible marker. The formulas were fed to the piglets over a 2-wk trial period. Digesta from the terminal ileum were collected post euthanasia and analyzed for AA content, along with samples of the formulas. True AA digestibility was determined after correcting for endogenous AA loss at the terminal ileum of pigs fed an enzyme-hydrolyzed casein-based diet, followed by ultrafiltration (5,000 Da) of the digesta. Total urine and feces collection was also undertaken to determine the nitrogen retention from the diets. The true ileal AA digestibility was similar between the goat and cow milk infant formulas for all AA except Gly and Trp. There was no significant difference in the nitrogen retention of piglets fed the two different formulas. The goat milk infant formula and the premium cow milk infant formula were similar in terms of protein quality.     

Goat milk feeding causes an increase in biliary secretion of cholesterol and a decrease in plasma cholesterol levels in rats

The hypocholesterolemic effect of goat milk with respect to cow milk observed in a previous study led us to examine the influence of goat and cow milk in the diet on certain aspects of biliary physiology in normal rats. The fat content in all diets was 10% but the lipid quality was varied: the standard diet was based on virgin olive oil, and the other 2 diets included fat obtained from lyophilized cow milk and goat milk. We characterized the bile secretion, including biliary phospholipid, cholesterol, and bile acid outputs, the interrelation between bile acids and bile lipids, and the lithogenic index. The consumption of goat milk in the diet, compared with that of cow milk, caused an increase in the biliary secretion of cholesterol together with a decrease in plasma cholesterol concentration, whereas values for bile phospholipids, biliary acid concentrations, and the lithogenic index remained normal. Moreover, consumption of this type of milk decreased plasma triglyceride concentration and therefore had a positive effect, similar to that of olive oil (standard diet), on the lipid metabolism; hence, it may be recommended for consumption by the general population.     

Effects of prilled fatty acids and calcium salts of fatty acids on rumen fermentation, nutrient digestibilities, milk production, and milk composition

Lactating Holstein cows averaging 193 d postpartum and fitted with rumen cannulae were used in two experiments to investigate the effects of supplementing Ca salts of fatty acids or prilled fatty acids to the diet on fermentation in the rumen, apparent total tract nutrient digestibility, milk production, and milk composition. Cows were fed ad libitum total mixed diets consisting of 45% concentrate and 55% forage. Treatments in Experiment 1 were: 1) control, 2) control plus 680 g/cow per d of Ca salts of fatty acids, 3) control plus 680 g/cow per d of prilled fatty acids, or 4) control plus 907 g/cow per d of prilled fatty acids. Treatments in Experiment 2 were: 1) control, 2) control plus 553 g/cow per d of Ca salts of fatty acids, or 3) control plus 454 g/cow per d of prilled fatty acids. Data suggest that Ca salts of fatty acids and prilled fatty acids are inert in the rumen and do not greatly alter fermentation in the rumen, apparent total tract digestibilities of DM, organic matter, ADF, NDF, and CP, or milk composition when fed at recommended amounts of 3 to 4% of the DM intake. The fact that milk production was not increased in these experiments by feeding Ca salts of fatty acids and prilled fatty acids may be attributed to the use of medium to low producing cows that were past the peak of milk production. Additional experiments are needed to obtain information about feeding these sources of supplemental fat to high producing cows during the early stages of lactation.     

Consumption of caprine milk improves metabolism of calcium and phosphorus in rats with nutritional ferropenic anaemia

This study investigates the effects of consumption of dietary caprine and bovine milk on Ca and P bioavailability, their distribution in different target organs, and parathormone (PTH) and corticosterone levels in rats with induced nutritional ferropenic anaemia (NFA). NFA increased the absorption of Ca and P, while their deposition in the femur was significantly lower, resulting in a significant degree of bone demineralization. Furthermore, anaemia led to an increased concentration in PTH and corticosterone in serum. Dietary caprine milk had a beneficial effect on Ca and P bioavailability in NFA, increasing the digestive and metabolic utilization of these elements and their deposits in the corresponding target organs, especially in the femur, together with lower levels of serum PTH. The opposite effect was observed for bovine milk diet. The consumption of caprine milk appears able to restore, at least in part, the impaired Ca and P metabolism and bone demineralization observed in rats with NFA.     

The effect of formulated goats' milk on calcium bioavailability in male growing rats

BACKGROUND: There are two main proteins in milk; whey and casein. Casein contains casein phosphopeptides (CPP), which are released on digestion of the milk. These may increase calcium solubility by binding calcium in the small intestine. Thus increasing casein in the diet may help to stimulate bioavailability of calcium and increase bone density. The present study tested this hypothesis in growing male rats fed diets containing three different concentrations of casein from goat milk. RESULTS: Rats fed the diet containing no casein had significantly lower calcium absorption when compared to rats fed the diets that contained 80% and 57% of goat milk protein as casein; however, no significant difference was observed between rats fed diets with 80% and 57% casein. The varying amounts of casein had no effect on mineral uptake or retention in the femur. Biomechanical testing and mineral analysis of the femurs showed no differences between diet groups. The mechanism to explain this lack of retention remains unclear. CONCLUSION: The diets containing 80% and 57% of goat milk protein as casein delivered increased calcium absorption compared to the diet containing no casein, suggesting a minimum level of casein is needed to optimize calcium absorption from goat milk. Copyright © 2009 Society of Chemical Industry     

Supplementation of the diet of dairy cows with trehalose results in milk with low lipid peroxide and high antioxidant content

The objective of this study was to investigate the effect of dietary supplementation with the disaccharides trehalose and cellobiose on antioxidant activity in rumen fluid, blood, and milk of dairy cows. Nine Holstein dairy cows housed in a free-stall barn were divided into 3 groups, with each group receiving a different dietary treatment (a control diet, a 1% trehalose-supplemented diet, or a 1% cellobiose-supplemented diet) following a 3 × 3 Latin square design. Feed intake and milk production increased in cows receiving the trehalose-supplemented diet compared with those receiving the control and cellobiose-supplemented diets. The total protozoa numbers in the rumen fluid of cows fed trehalose- or cellobiose-supplemented diets were greater than those of the control group. The C18:0 and C18:1 fatty acid content was increased in the milk of cows fed the trehalose-supplemented diet compared with that of the control group, and the C18:3n-3 fatty acid content in the milk of cows fed the cellobiose-supplemented diet was less than that of the control group. Plasma biochemical parameters were unchanged among the different treatments. In rumen fluid, 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide dismutase activity were increased 2 h after feeding in cows receiving the cellobiose-supplemented diet compared with the control group, and the concentration of thiobarbituric acid reactive substances in the rumen fluid of cows fed the cellobiose-supplemented diet was decreased. In contrast, the values of these parameters measured in the milk of cows fed the cellobiose-supplemented diet were no different from those of control cows. Dietary supplementation with trehalose did, however, bring about an improvement of the oxidative status of milk and blood in these animals compared with controls. These results provide the first evidence supporting the use of dietary disaccharides to decrease lipid peroxide levels and increase the antioxidant content of dairy cow milk. The findings suggest that disaccharides, particularly trehalose, might be useful as supplements for reducing oxidative stress and improving the quality of milk for human consumption, as well as possibly impairing the processes that give rise to lipid oxidation odor in dairy cow milk.     

Mineral retention in three-week-old piglets fed goat and cow milk infant formulas

Goat milk and cow milk are commonly used in infant formula preparations and, as such, understanding the nutritional characteristics of infant formulas made from these milks is important. In this study, a goat milk infant formula was compared with an adapted (whey-enhanced) cow milk infant formula with respect to mineral absorption and deposition using the 3-wk-old piglet as a model for the 3-mo-old infant. Equal numbers of piglets (n = 8) were fed either the goat milk formula or the cow milk formula. The mineral composition of the prepared goat milk formula was higher than that of the prepared cow milk formula for most minerals, including calcium (75.1 vs. 56.7 mg/100 mL) but excluding iron, which was higher in the prepared cow milk formula (0.92 vs. 0.74 mg/100 mL). The amounts of calcium, phosphorus, and manganese absorbed by the piglets were significantly higher for the goat milk formula, whereas the amounts of zinc, iron, and magnesium absorbed were significantly higher for the cow milk formula. Apparent mineral absorption, relative to intake, was statistically higher in the cow milk formula for calcium and phosphorus, although the actual differences were very small (less than 1.3%). For copper, zinc, iron, and magnesium there was no significant difference between treatments in apparent mineral absorption, whereas for manganese, absorption was higher for the goat milk infant formula. The absolute mineral deposition was higher in piglets fed the goat milk formula for calcium, phosphorus, and manganese, whereas iron deposition was higher in the piglets fed cow milk formula. For all other minerals tested, there were no significant differences between treatments. The goat milk infant formula provided a pattern of mineral retention in the 3-wk-old piglet very similar to that of the adapted cow milk infant formula. The minor differences observed between the 2 appeared to be due to the different mineral contents of the 2 formulas.