Fecal Ca Research Articles

Effect of Inorganic Sulfate and Sulfur Amino Acids on Bone Mineralization in Broilers

Two experiments with a factorial arrangement of treatments were conducted to determine the effect of inorganic sulfate and sulfur amino acids (SAA) levels on bone mineralization and Ca excretion in broilers from 1 to 21 days of age. Experiment 1 included two levels of Ca (.6 and 1.0%), two sulfate sources [copper sulfate (CuSO4·5H2 O), and potassium sulfate (K2 S4 O)], and three sulfate levels (.024, .034, and .044%). Experiment 2 included two Ca levels (.6 and 1.0%), two CP levels (18 and 22%), and three SAA levels (.93, 1.23, and 1.53%). Body weight gain, feed:gain, feed consumption, and tibia variables were measured in both experiments. In Experiment 2, Ca retention was also assessed. In Experiment 1, birds fed potassium sulfate and .6% Ca gained significantly more weight than birds fed copper sulfate and 1.0% Ca, respectively. As sulfate level increased, tibia ash percentage increased and decreased linearly in birds fed copper sulfate and potassium sulfate, respectively (P < .012). In Experiment 2, birds fed 1.0% Ca, .93% SAA, and 22% CP performed better than the birds receiving the other levels. A low Ca level (.6%) was more detrimental for bone mineralization in birds fed 22% CP compared with birds fed 18% CP. There was no effect of SAA on tibia ash and Ca percentages. Fecal Ca excretion decreased linearly with SAA level (P < .01). The results suggest that inorganic sulfate from the potassium salt may adversely affect Ca deposition in bone. However, SAA supplementation up to 65% in excess of the requirement in starter broiler diets did not affect bone mineralization.

Effect of Cadmium on Bone Calcium and 45Ca in Nonpregnant Mice on a Calcium-Deficient Diet: Evidence of Direct Effect of Cadmium on Bone

To clarify the mechanism of the effect of Cd on bone, virgin female mice with 45Ca prelabeled skeletons (15 μCi/mouse) were exposed to a Ca-deficient diet (0.002%) containing 0, 5, or 25 ppm Cd or 25 ppm Pb for 32 days. During the first 72 hr, the 0 ppm controls showed a 2.5-fold decrease in fecal 45Ca excretion (decreased bone resorption), a 12-fold decrease in total fecal stable Ca, a 5-fold decrease in endogenous fecal Ca excretion, and a significant elevation in both serum 45Ca (108%) and specific activity (92%) due to the Ca-deficient diet. In contrast, Cd immediately and significantly increased fecal 45Ca excretion (55%), total fecal stable Ca (13%), endogenous fecal Ca excretion (32%), as well as serum 45Ca (15%) and specific activity (17%) (25 ppm Cd vs 0 ppm), supporting the hypothesis of an early, direct effect of Cd on bone. Overall, during 32 days, Cd at 25 ppm induced a 60% increase in fecal 45Ca excretion compared to 0 ppm controls, providing a sensitive measure of the Cd-induced increase in bone resorption. In contrast, the effect of Cd was too small to cause a statistically significant 45Ca loss from the right femur and lumbar vertebrae, but a significant 45Ca loss (up to −13%) was seen for the remaining skeleton (25 ppm vs 0 ppm group). In addition, Cd at 25 ppm induced small but statistically significant decreases in ash weight (−12%), ashweight to dry weight (−5%), Ca/dry (−7%), and Ca/ash (−2%) in the right femur and significant decreases in ash/dry (−7%) and Ca/dry (−12%) in the lumbar vertebrae compared with the controls. Our present study supports the hypothesis that Cd at 25 ppm had a significant direct effect on bone, with no effect at 5 ppm Cd or 25 ppm Pb, and no appearance of the extreme demineralization characteristic of Itai-Itai disease, although mice were exposed to a Ca-deficient diet for 32 days. Our results from this and earlier studies support the view that chronic Cd exposure along with nutritional deficiency contributed to the pathogenesis of Itai-Itai disease among multiparous, postmenopausal women in Japan.

Biochemical changes and essential metals concentration in lead-intoxicated rats pre-exposed to ethanol

The effects of chronic lead exposure on some hematopoietic and hepatic biochemical indices and urine, feces, and tissue essential metal concentration were investigated in rats pre-exposed to different doses of ethanol. Exposure to ethanol (0.5, 1.0, and 2.0 g/kg intraperitoneally, once daily) for 4 weeks produced an inhibition of blood δ-aminolevulinic acid dehydratase (ALAD) activity and a decrease in hepatic glutathione (GSH) concentration. Ethanol ingestion also produced a dose-dependent elevation of hepatic lipid peroxidation. Blood and hepatic calcium and hepatic magnesium contents decreased and urinary Ca and fecal Ca and Mg contents increased significantly following 4-week exposure to ethanol (2 g/kg). Lead administration (10 mg/kg, orally) for 4 weeks in ethanol pre-exposed (2 g/kg) animals produced a more pronounced inhibition of blood ALAD and elevation of urinary δ-aminolevulinic acid (ALA) excretion and hepatic GSH contents. Hepatic GSH contents decreased and hepatic lipid peroxidation increased significantly in rats given lead and pre-exposed to ethanol (2 g/kg). A more pronounced depletion of blood Ca and Mg and hepatic Mg was observed along with significant elevation of urinary Mg and fecal Ca excretion in animals administered lead and pre-exposed to ethanol (2 g/kg). The results suggest that nutritional deficiencies, particularly depletion of body Ca and Mg levels, play an important role in increasing susceptibility to lead intoxication in the rat.

Dual Tracer Stable Isotopic Assessment of Calcium Absorption and Endogenous Fecal Excretion in Low Birth Weight Infants

Using a dual tracer (44Ca orally and 46Ca i.v.) stable isotope technique, true dietary Ca absorption, endogenous fecal Ca excretion, and net Ca retention were measured in 12 low birth weight (1426 +/- 260 g) infants fed a high Ca-containing formula. Endogenous fecal Ca excretion averaged 7.2 +/- 4.1% of intake, and exceeded 10% of intake in three infants. Net Ca retention, 103 +/- 38 mg/kg/d, was consistent with previous studies of Ca retention obtained using mass balance techniques and correlated closely (r = 0.98, p less than 0.001) with true Ca absorption but not with endogenous fecal excretion (r = -0.40, p = 0.19). Although endogenous fecal excretion may represent a significant source of Ca loss for some low birth weight infants, these data suggest that net Ca retention in low birth weight infants fed a high Ca-containing formula is primarily determined by the total dietary Ca absorbed.

COMPARISON OF FORAGE DIGESTION BY CATTLE AND HORSES

Two trials compared digestion of Saskatchewan-grown hays by cattle and horses. In the first study, Altai wildrye (Leysum angustus Trin.), smooth bromegrass (Bromus inermus Leyss.), crested wheatgrass (Agropyron cristatum L.), Kentucky bluegrass (Poa pratensis L.), oat hay (Avena sativa L.) and reed canarygrass (Phalaris arundinaceae L.) hays were fed to six beef steers and six crossbred geldings. The second study compared alfalfa hay (Medicago sativa L.) to dehydrated alfalfa pellets. Voluntary dry matter intake (VDMI) of hay by cattle was related to neutral detergent fiber content (R2 = 0.66). No single nutrient reliably predicted VDMI by horses. Cattle and horses had the highest VDMI for bromegrass hay in trial 1. Cattle had similar intakes of dehydrated alfalfa pellets and alfalfa hay, but horses ate 17% more (P &lt; 0.05) hay than pellets. Cattle digested 28–82% more (P &lt; 0.05) fiber from grass hays than horses which may account for their higher dry matter (DM) digestion of these hays. Cattle and horses utilized legume feeds similarly. Energy intakes of all animals exceeded maintenance except for cattle fed reed canarygrass hay. True crude protein digestibility and metabolic fecal protein of forage-fed cattle and horses were estimated at 83.4 and 80.3%, and 2.67 and 2.17 g 100 g−1 DM intake, respectively. Horses had higher true digestibilities of Ca (75%) than P (33%) but cattle digested more P (76%) than Ca (32%). Endogenous fecal Ca excretion for cattle and horses were assessed at 6.5 and 22.1 mg kg−1 body weight (BW), respectively, while endogenous fecal P excretions were 13.3 and 10.2 mg kg−1 BW, respectively. Key words: Horse, cattle, legume, grass, crude protein, fiber

Effect of sodium and potassium level on the absorption of magnesium and other macrominerals in sheep

Three mature Suffolk × halfbred wethers were utilized to study the effect of dietary sodium (Na) and potassium (K) level on the absorption of magnesium (Mg), Na, K, calcium (Ca) and phosphorus (P). The sheep were surgically equipped with a rumen fistula and re-entrant cannulae in the proximal duodenum and terminal ileum. Six semi-purified diets were prepared with three levels of sodium and two levels of potassium and constant levels of other elements in all six diets. Mg absorption before the small intestine decreased with increased K and a negative correlation was found between K intake and net Mg absorption before the small intestine. The addition of K to the diet increased fecal Mg, and decreased urinary Mg excretion and apparent absorption of Mg. Increasing K levels in the diet decreased the plasma Mg concentration and there was a negative correlation between K intake and plasma Mg concentration. A significant negative correlation between net Mg absorption before the small intestine and rumen pH was found. The level of Na per se in the diet was not an important factor affecting Mg metabolism but the Na/K ratios in feed and rumen liquor were. Supplementation of K, increased the urinary and fecal Ca excretion while Na in the diet increased the concentration of blood plasma P. No other changes in Ca or P metabolism were observed. K level in the diet depresses Mg absorption and Na can be used in high K diets to counteract the effects of K on Mg absorption.

Bone growth and calcium balance during simulated weightlessness in the rat

Rats, age 28 days, experiencing tail suspension in modified metabolic cages for 1, 2, and 3 wk were compared with littermate controls. Food and water consumption, urinary and fecal Ca excretion, and serum Ca were measured; hearts, fore- and hindlimb bones, skulls, and mandibles were removed for determination of wet, dry, and ash weights and Ca concentration and for histological examination. Weight gain and Ca intake and excretion were the same for both groups; both displayed net Ca gain. Suspended rats had significantly lower wet, dry, and ash weights of femora and tibiae. Dry weights of the humeri and radii/ulnae were moderately higher, and the skull and mandible dry and ash weights were significantly higher in suspended than in control rats. Cortical thickness of the femur, but not humerus, was less in suspended rats. The data are consistent with the hypothesis that bone growth is influenced by the cardiovascular changes associated with tail suspension.

Measurement of Calcium and Phosphorus Fluxes During Lactation in the Rat

Novel, two-compartment metabolic cages for rats were constructed to examine Ca and P fluxes during lactation. Four consecutive balance studies of 4 d each were performed in lactating rats and nonlactating controls. Lactating rats had dramatically higher intestinal absorptions of Ca and P resulting from both increased food consumption and elevated fractional absorptions of these elements. Urinary Ca excretion was reduced during lactation whereas urinary P excretion was unchanged. Endogenous fecal Ca excretion (determined by infusing 45Ca and dividing fecal 45Ca content by urinary 45Ca specific activity) was similar in lactating and nonlactating rats. In a separate study, pup retention of ingested Ca averaged 96%. Therefore, the difference in pup carcass Ca content between d 1 and 17 of age is assumed to equal 96% of the Ca transfer rate into milk. Similar calculations were applied to P. Milk transfer rates were determined to be 126 and 99 mg/d for Ca and P, respectively. These calculations indicate that 19% of the Ca transferred to milk was derived from the maternal skeleton with the maternal diet supplying the remaining Ca. This study provides the first comprehensive analysis of the alterations in Ca and P fluxes that occur during lactation in the rat.

Effect of phosphorus on endogenous calcium losses during total parenteral nutrition

Intravenous phosphorus can reduce urinary calcium losses in patients receiving total parenteral nutrition (TPN). We investigated the effect of intravenous P on urinary and fecal Ca loss in intravenously fed normal and thyroparathyroidectomized (TPTX) rats to assess the role of parathyroid hormone (PTH) and endogenous fecal Ca losses. Doubling the intravenous P load during TPN decreased urinary Ca losses by 54% (0.299 vs 0.137 mmol/d) in intact rats and by 43% (0.514 vs 0.294 mmol/d) in TPTX rats. Increased P load in normal rats had no effect on urinary cyclic AMP excretion, serum Ca, serum P, serum 1,25-dihydroxycholecalciferol, or endogenous fecal Ca losses. These observations suggest that the hypocalciuric effect of P during TPN is independent of PTH and is not caused by a repartitioning of obligatory Ca losses from the renal to the intestinal route.

Effects of dietary phosphorus, soil ingestion and dietary intake level on performance, phosphorus utilization and serum and alimentary tract mineral concentrations in lambs.

Two experiments were conducted with lambs fed concentrate-based diets to study the effects of dietary P and soil ingestion on performance, P utilization and mineral composition of serum and alimentary tract contents. In Exp. 1, 20 wether lambs were fed diets for 21 d in a 2 X 2 factorial arrangement of treatments with .2 or .3% total dietary P and O or 9% added Florida Ultisol (highly weathered soil with high P-fixation capacity) containing 4,600 and 6,400 mg/kg total Al and Fe, respectively. True P absorption increased (P less than .05) from 30 to 42% and from 37 to 54% when soil was added to the basal and high P diets, respectively. In Exp. 2, 24 wether lambs were assigned randomly to a 2 X 2 X 2 factorial arrangement of treatments. Lambs were fed during a 70-d period using diets described previously on either a restricted or an ad libitum basis. Soil increased Fe concentration in ruminal fluid (P less than .05) and ash percentage (P less than .001) in ruminal solids and feces. Aluminum concentration in ruminal solids and feces and Fe in ruminal solids were increased (P less than .001) by soil addition, whereas concentrations of Ca, Mg, P, Zn, Cu and Mn in ruminal solids and feces were decreased (P less than .01) by soil addition. There were time X P interactions on serum inorganic P (P less than .01) and Mg (P less than .05) concentrations. Although high in P-fixing capacity, soil fed to lambs in these experiments improved P utilization. Lambs appeared to be able to adapt to changes in intake of dietary minerals in soil, possibly through adaptation of ruminal microflora or a redistribution of body mineral pools.

Growth, liver composition, and calcium balance of rats fed sorghum supplemented with two levels of beans.

A 35-day experimental study consisting of 28-day growth and 7-day calcium (CA) balance periods was conducted to assess the effects of fibre and N ratios on growth and Ca balance of rats. Growth and Ca balance of rats (45 80 g) fed mixtures of cooked (CS) and uncooked (RS) sorghum and dehulled (DB) and undehulled (UB) bean were studied. The diets contained 10% protein. Casein served as the control protein. The control group ate more food except for the group fed the CS:DU (60:40) diets (P less than 0.05) had higher values for all parameters tested than the test groups. There were increases in food and Ca intakes, fecal Ca, weight gain, protein efficiency ration (PER), liver weight and composition except for the low moisture value for the CS:DS (60:40) group when N ratios were changed from 80:20 to 60:40. These results appear to indicate that fiber and N ratio had significant effects on growth liver composition and calcium balance of the rats.

Calcium Metabolism in Children Recovering from Severe Protein‐Energy Malnutrition

SummaryTwenty preschool children with severe edematous protein‐energy malnutrition (PEM) were studied during the first 45 days of recovery. All children received 4 g/kg/day of protein and 150 kcal/kg/day of energy from a milk‐based recovery formula, providing 130–140 mg/kg/ day of calcium (Ca). Children were randomized to two treatment groups, one receiving intact milk formula and the other a lactose‐free preparation. Both groups showed a high efficiency of intestinal calcium absorption, sustained even after the normalization of weight for height and lean body mass. The presence or absence of lactose in the diet did not affect intestinal calcium absorption, and increased stool volume in the early period of recovery in the children receiving intact milk was not associated with higher fecal Ca losses. Urinary Ca excretion was within the range reported for healthy children under a normal diet. These results suggest that therapeutic amounts of calcium should be delivered to children with PEM well beyond the normalization of body weight and lean body mass.

Mineral absorption in relation to nutritional ecology of reindeer

This paper addresses the way which absorption of minerals relate to nutritional ecology and mineral conservation processes. A latin square designed experiment was used to assess the effects of diet on mineral (Ca, Mg, K, Na) absorption processes in reindeer (Rangifer tarandus L.). Three male calves were fed 3 different diets: concentrate with 25% grass meal (RF-71), lichens, and a mixed diet of lichens and RF-71. Two other male calves were fed the lichen or mixed diet, supplemented with 4 g Ca/day. Ca supplementation significantly increased fecal Ca excretion, reduced the excretion of K and Mg, but had no significant effect on Na excretion. Rates of intake and fecal exretion of Ca, Mg and K were highly correlated (P&amp;lt;0.001), while no correlations were found for Na. Negative digestibilities of Ca, Mg and K, and a positive Na digestibility were noted for the lichen diet. For the other diets, all minerals were in positive digestibility, and Ca supplements increased the digestibility of all minerals. Digesta from different sections of the alimentary tract were collected after termination of the experiment. Alimentary pools of Ca and K were equal for animals fed lichen or RF-71, whereas the Na pool was largest on the lichen diet and the Mg pool largest on the RF-71 diet. Rumen turnover time (rumen mineral pool size/daily mineral intake) was consistently less than 3 days for Ca and Mg, but was 22 and 82 days for Na on the RF-71 and lichen diets respectively. Estimates of mineral exchange in various parts of the tract showed that the intestines play and important role in scavanging endogenously secreted minerals. Results are discussed with respect to mineral binding by lichens and the possible role of natural mineral supplements in the nutritional ecology of reindeer.

Effect of rice hemicellulose and microcrystalline α-cellulose on selected minerals in the blood and feces of rats

The effects of purified, water-soluble hemicellulose from rice bran, and of microcrystalline α-cellulose, Alphacel, on Cu, Zn, Fe, Ca, Mg and Mn levels in blood and feces of rats were studied. Three groups of five rats were fed for 14 days on standard casein-based diets containing 3 % (w/w) rice hemicellulose or 3 % (w/w) Alphacel ; rats fed on a fiber-free diet served as the control group. Rat feces showed an increased content in all of the minerals when the diet was supplemented with rice hemicellulose or Alphacel. With the exception of Mn, which showed greater fecal excretion when the diet was supplemented with hemicellulose, the remaining minerals showed higher fecal mineral excretion when the diet was supplemented with Alphacel. Separation of the feces into water-soluble and insoluble fractions revealed that greater amounts of minerals were present in the insoluble fraction than in the water-soluble fraction. Blood from rats fed with the hemicellulose diet showed a decrease in Ca, Mg and Fe and essentially no change in Mn, Cu and Zn. Blood from Alphacel-fed rats showed an increase in Ca, Fe and Zn, a decrease in Mg and no change in Mn and Cu, compared with the control diet.

A role for the intestine in the bone disease of juvenile X-linked hypophosphatemic mice: malabsorption of calcium and reduced skeletal mineralization.

Low duodenal vitamin D-dependent calcium-binding protein has been reported in juvenile Hyp mice. Levels of this protein improved in adult Hyp mice. This led to the search for possible abnormal intestinal calcium absorption in juvenile Hyp mice and for evidence that calcium malabsorption, if present, would exacerbate the bone disease. A balance study was performed in 10 sets of normal and Hyp male mice at 5 and 12 weeks of age. Twelve-week-old Hyp mice had balances (24-h intake minus excretion) of Ca, P, Mg, Na, and K that were not significantly different from those of 12-week-old normal mice. However, 5-week-old Hyp mice had a significantly lower balance of Ca with higher fecal Ca and lower urinary Ca. No balance was also lower due to higher fecal Na. The balances of P, Mg, and K were not significantly affected in young Hyp mice. Growth and mineralization of the femur were compared in normal and heterozygous female Hyp mice from 3.5-46 weeks of age. The femora of Hyp mice gained ash weight at a rate comparable to that for normal mice, except for a lag between 3.5 and 7 weeks. There was life-long hypophosphatemia and elevated plasma alkaline phosphatase. It was concluded that the period of low levels of duodenal vitamin D-dependent calcium-binding protein was associated with low intestinal absorption and low skeletal mineralization. This dysfunction of the intestine in juvenile, rapidly growing Hyp mice may exacerbate the bone disease.

Calcium Status of the Growing Rat as Affected by Diet Acidity from Ammonium Chloride, Phosphate and Protein

Two trials of 4 and 8 weeks' duration were conducted on 64 male Long-Evans growing rats to study effect(s) of diet protein (20 and 40%), phosphate source (less or more acidic) and NH4Cl (none or 1% in water) on Ca status and acid-base balance. Treatments were arranged in a 2 × 2 × 2 factorial plan in four randomized blocks. All diets were equal in Ca (0.52%) and P (0.41%). Criteria were blood pH and bicarbonate, plasma hydroxyproline and Ca, urinary cAMP and Ca, fecal Ca, and mineral analyses and gravimetric measurement of femurs. Blood pH was lowered due to NH4Cl ingestion at 4 weeks (7.11 and 7.22, P < 0.05) and 8 weeks (7.27 and 7.36, P < 0.02). Protein level and phosphate source influenced blood bicarbonate. With the ingestion of more acid there were increases in urinary cAMP and Ca. Fecal Ca increased twofold with more acid. Femur specific gravity was higher with the less acidic phosphate source. In conclusion, acid phosphate, NH4Cl and protein influenced blood pH and loss of Ca via urine and feces with a resultant lowered bone density. The less acidic phosphate source reduced or prevented a lowered bone density.

Effects of Sodium Bicarbonate and 1,25-Dihydroxy-cholecalciferol on Calcium and Phosphorus Balances in the Rat

Metabolic balance studies were undertaken to determine whether sodium bicarbonate (NaHCO3) supplements (4.5 mmol/day) altered 7-day cumulative calcium (Ca) phosphorus (P) balances in growing rats consuming either a basal diet providing 0.6% Ca and 0.3% P, or this diet plus 1,25-dihydroxycholecalciferol [40 ng 1,25(OH)2D3/day]. Feeding bicarbonate lowered urinary Ca but raised fecal Ca so that Ca balance became less positive. However, 1,25(OH)2D3 increased net absorption of Ca and P to the same degree when given to control rats and rats consuming bicarbonate. Nevertheless, bicarbonate-fed rats had lower net Ca absorption than controls, even when treated with high doses of 1,25(OH)2D3. Changes in net Ca absorption induced by bicarbonate may occur at a point in the gut distal to the duodenum since duodenal 45Ca absorption was not decreased by bicarbonate feeding. The present results show that bicarbonate consumption depressed net Ca absorption in the rat. The effect appears to be independent of changes in 1,25(OH)2D3 metabolism because it is manifest in animals receiving high doses of 1,25(OH)2D3, which stimulate alimentary Ca absorption maximally, and because bicarbonate-fed rats are able to respond normally to exogenous 1,25(OH)2D3 by increasing their net absorption of Ca and P. In view of this demonstration that NaHCO3 supplements elevate fecal Ca loss in the rat, it is suggested that studies should be undertaken to determine whether bicarbonate exerts similar adverse effects on Ca balance in humans.

The long-term effects of pancreatectomy on the Ca metabolism of the rat.

The Ca metabolism of pancreatectomized (PX) rats was investigated three months after surgery. Most PX animals were in negative Ca balance because of increased endogenous fecal Ca excretion and reduced true Ca absorption. Significant increases were also observed in bone Ca resorption rates, hydroxyproline excretion and size of osteocyte lacunae. Inverse correlations between the rates of bone Ca resorption and Ca balance were observed in the PX and control groups. Significantly, both correlations were found to fit the same function. It was concluded that parathyroid hormone secretion and its metabolic expression were not impaired by pancreatectomy. The coupling between bone Ca accretion and resorption was absent in PX animals: high resorption rates were found associated with normal or decreased accretion rates. These latter rates, in combination with the negative Ca balance, explain the reduction in the skeletal Ca mass.

Absorption and secretion of calcium and phosphorus in the alimentary tract of lambs infected with daily doses of Trichostrongylus colubriformis or Ostertagia circumcincta larvae

The flows of endogenous and exogenous calcium and phosphorus in the digesta at the abomasum, ileum and in the faeces were measured in growing lambs infected daily with 3000 T. colubriformis larvae (TC), 5000 O. circumcincta larvae or no larvae. The lambs were given 0·70 or 1·0 kg per day of a pelleted diet and the flow rates were measured by reference to soluble and particulate radioactive markers. The fraction of Ca and P in digesta of endogenous origin was measured by the method of isotope dilution involving a single intravenous dose of 45Ca or 32P. Ostertagia circumcincta infection was without effect on the absorption and secretion of Ca and P in the digestive tract, other than producing a small but significant increase in the endogenous faecal Ca excretion. There was, however, a striking increase in the flow of digesta at the abomasum, the DM and Na content of which was consistent with an increased secretion from the mucustype cells in the abomasal mucosa. The extra digesta was absorbed in the small intestine. Trichostrongylus colubriformis infections reduced the absorption of exogenous P by about 30 per cent and increased losses of endogenous P due to the action of worms on the mucosa of the small intestine. The net effect of this was to induce a P deficiency in TC lambs, leading to a reduced flow of salivary P and a reduction in the plasma concentrations of P. The effect of TC on Ca metabolism was limited to an increase in endogenous faecal excretion.

Intestinal and renal loss of infused minerals in patients with severe short bowel syndrome

Intestinal and renal loss of infused calcium, magnesium, and zinc were studied in eight patients on permanent partial parenteral nutrition because of extensive bowel resection by comparing two 4-day infusion periods, one with Ca/Mg/Zn supplied (B) and one without (A). Dietary intake and parenteral supply of other nutrients were constant. In period B the daily supply of 9 to 11.3 mmol Ca, 10 mmol Mg, and 70 to 200 mumol Zn was infused over a 4-h period during which S-Ca increased by 8%, S-Mg by 37%, and S-Zn by 60%. During Ca/Mg/Zn infusion renal Ca excretion increased with 81% of the amount of Ca infused. Mg loss with 63% of infused Mg, and Zn loss with 8% of infused Zn. Increased fecal loss of Ca and Mg occurred in patients with functioning colon, but not in patients with jejunostomy. Fecal Zn increased in both groups. Increased fecal Ca presumably reflected impaired absorption of dietary Ca, since endogenous fecal Ca loss was unchanged. The kidneys represented main excretory route for infused Ca and Mg and the gastrointestinal tract was the main excretory route for infused Zn. The majority of patients had a net retention of infused Ca (16%), Mg (27%), and Zn (61%).