Tolerance evaluation of overdosed dietary levels of 25-hydroxyvitamin D3 in growing piglets.

Forty-eight, cross-bred (GL × LW × P) piglets were used in a 42-day tolerance trial to assess the effects of feeding diets supplemented with vitamin D or increasing levels of 25-hydroxyvitamin D3 (25-OH-D3 ). Six-week-old piglets (24 castrate males, 24 females) were used. Two replicate groups of 6 piglets were randomized by weight and allocated to four dietary treatments. The control group (T1) was supplemented with 50 µg vitamin D3 /kg feed. The experimental groups received 25-OH-D3 at the recommended dose (T2: 50 µg/kg = 1x), at 250 µg/kg (T3: 5x) or at 500 µg/kg (T4: 10x) respectively. Feed intake and daily weight gain were measured weekly, and the animals were examined by a veterinarian daily. After 42 days, body mass, blood, urine, bone and tissue samples were analysed and a pathology examination conducted. Dietary treatments had no significant effect on final body mass or daily weight gain. The 25-OH-D3 plasma concentration in T1 was 17 ± 3 ng/ml (mean ± SD) while the respective values of the experimental groups were significantly increased in T2, T3 and T4. Tissue concentrations of 25-OH-D3 were higher in liver and muscle for T3 and T4 and in skin for T4 than in T1. However, neither gross pathology nor histology, nor blood and urine characteristics, nor bone parameters were affected by dietary treatments. Weight of organs as well as dry matter, ash and calcium content of kidneys remained unaffected by dietary 25-OH-D3 intake. Furthermore, no changes were observed for general indicators of health. The results of this study demonstrated that feeding piglets with 25-OH-D3 at 5 or 10 times the recommended level had no adverse effects on any of the biological parameters measured. It was concluded that 25-OH-D3 can be regarded as a supplement with a very high safety margin when used at the recommended level.

Safety profile of 1,25-dihydroxyvitamin D3 of herbal origin in broiler chicken.

INTRODUCTION: The safety of supplementing broiler feed with a standardised herbal extract, Solanum Glaucophyllum Standardised Leaves (SGSL) containing glycosylated 1a,25-dihydroxyvitamin D3 (1,25(OH)2D3) and standardised to contain 10 µg/g 1,25(OH)2D3 equivalent, was examined in two studies. In a first study, we examined the potential of SGSL to substitute vitamin D3 (VD3) and the tolerated dose range of SGSL when applied without concomitant VD3 by analyzing performance and blood chemical parameters after 14, 25 and 38 days on diets containing two doses of SGSL (1 and 10 g/kg feed) as source of 1,25(OH)2D3. In the second study, the no adverse effect level of SGSL was determined by analyzing the same parameters after 35 days on diets containing basic VD3 supply and in addition 0.2, 1.0, 2.0 and 4.0 g of SGSL/kg feed. We showed that SGSL was able to substitute VD3 in broilers as far as the performance parameters were concerned. Also, we found that the no adverse effect level is at least 4 g SGSL/kg feed when used with moderate doses of VD3. This is 20 times higher than the upper limit of the commercially recommended dose. We concluded that SGSL is a safe feed additive to use in broiler chicken.

INTRODUCTION: Dans la cadre de deux études, on a examiné la sécurité de l'extrait de plante standardisé Solanum Glaucophyllum Standardised Leaves (SGSL) comme complément alimentaire chez les poulets d'engraissement. Le SGSL contient de façon standardisée 10 µg/g de 1,25(OH)2D3 sous forme glycolysée. Dans la première étude, on a examiné le potentiel d'action en tant que remplaçant de la vitamine D3 (VD3) et le domaine de dose de SGSL toléré, ceci en ne donnant que du SGSL sans addition de VD3 . On a examiné la performance et les paramètres de chimie sanguine après 14, 25 et 38 jours d'affouragement de deux doses différentes (1 et 10 g/kg d'aliment) de SGSL comme source de 1,25(OH)2D3. Dans la seconde étude, on a recherché le No Adverse Effect Level sur la base des mêmes paramètres après 35 jours avec une alimentation contenant, outre une quantité modérée de VD3, 0.2, 1.0, 2.0 et 4.0 g de SGSL/kg. On a pu démontrer que le SGSL peut remplacer la vitamine D3 chez les poulets d'engraissement en ce qui concerne les performances étudiées. Le No Adverse Effect Level se situait aux environs d'au moins 4g de SGSL/kg d'aliment lorsqu'il était associé avec des quantités modérées de Vitamine D3. Cette dose est vingt fois supérieure à la dose maximale recommandée par le fabriquant. Nous en déduisons que le SGSL est un complément alimentaire sûr pour les poulets d'engraissement.

The efficacy of a standardised product from dried leaves of Solanum glaucophyllum as source of 1,25-dihydroxycholecalciferol for poultry.

1. Chemical characterisation of an extract of Solanum glaucophyllum (SG) leaves affirmed the predominant presence of 1,25-dihydroxycholecalciferol (1,25(OH)2D3) glycosides. The compound 1-(ß-D-glucopyranosyl)-1α,25-dihydroxycholecalciferol was isolated for the first time from a natural source. 2. Vitamin D activity of the extract was confirmed by the calcaemic properties shown in a quail eggshell bioassay. The results suggested a 1,25(OH)2D3 bioavailability of approximately 15%. 3. A broiler feeding experiment replicated in time was carried out with 6 treatments. A basic control diet containing 25 µg cholecalciferol/kg was supplemented with 2.5 and 5 µg free 1,25(OH)2D3/kg, with a product based on dried SG leaves (Panbonis) providing 10 µg of 1,25(OH)2D3-glycosides/kg, with two concentrations of an SG extract providing 8.8 and 37.8 µg of 1,25(OH)2D3-glycosides/kg. 4. Tibia breaking strength and stiffness were numerically greater in all treatment groups with free 1,25(OH)2D3 and with SG products compared to controls, though the overall treatment effects only had probabilities in the range of P = 0.07 to P = 0.1. Values for both characteristics increased progressively, with additions of synthetic 1,25(OH)2D3; values with the dried SG product were similar to those with 5 µg synthetic 1,25(OH)2D3/kg. 5. Plasma calcium was mildly elevated (P < 0.05) in treatment groups. The SG extract treatment containing 37.8 µg 1,25(OH)2D3/kg gave the highest plasma calcium concentration and lowest bodyweight, signs of marginal hypervitaminosis D. Plasma 1,25(OH)2D3 concentrations were in the normal range for all treatments. 6. Tibial dyschondroplasia occurred in only one replicate. The incidences were 31% in controls but considerably lower or zero with all other treatments. 7. Bioavailability of 1,25(OH)2D3 in the SG product seemed to be higher in broiler chickens than in Japanese quails. 8. It is concluded that the inclusion of the dried SG product as a source of vitamin D3 in broiler diets at a dietary concentration of 1 g/kg, providing 10 µg 1,25(OH)2D3/kg, is safe and efficacious.

Effect of low doses of dietary rare earth elements on growth performance of broilers.

The present study was designed to investigate effect of dietary rare earth elements (REE), including both organic and inorganic compounds, on growth performance of broilers. In experiment 1, a total of 180 male Ross broiler chicks were allocated to 72 pens with different assignment: four chicks per pen or individually. The following three treatment diets were applied: control, REE-chlorides at a dose of 40 mg/kg and REE-citrate at a dose of 70 mg/kg. Each treatment group had 24 pens containing both assignments (12 pens each). In experiment 2, a total of 72 male 3-day-old Ross broiler chicks were separated to four groups: control, REE-chlorides at a dose of 70 mg/kg and REE-citrate at doses of 70 mg/kg and 100 mg/kg. In experiment 1, dietary REE-citrate improved body weight gain during the overall period by 5.0% (p < 0.05) while the increase with REE-chloride was not significant. In experiment 2, growth effects (p < 0.05) were only found in the period from day 21 to slaughter with all REE forms, and feed conversion ratio was improved by 3.4% (p < 0.05) with REE-citrate. No significant effects of REE were found on chill weight, percentages of breast meat, thigh weight, drumstick weight and wing weight. Concentrations of La and Ce in the liver and muscles were very low, accounting for 0.11-0.76 and 0.02-0.30 mg/kg respectively. There was weak tendency for a dose-response relationship especially in the groups supplemented with REE-chlorides. The main blood serum biochemical parameters were not significantly affected by REE in the diets. The results suggest that dietary supplementation of low doses of REE-citrates might improve growth performance of broilers without affecting carcass composition and health of the broilers.

Glycerol phosphate shuttle in virus-transformed cells in culture.

The glycerol phosphate shuttle is shown not only to be present and functional in virus-transformed cells, but its level is higher than in normal cells in culture. The increased aerobic glycolysis that has been demonstrated for these cells after transformation, therefore, is not due to an impairment of hydrogen transfer pathways.

Prevention of osteoporosis after cardiac transplantation: a prospective, longitudinal, randomized, double-blind trial with calcitriol.

BACKGROUND: Accelerated bone loss is a well-recognized complication after cardiac transplantation (HTx) due to immunosuppressive therapy. The purpose of this prospective, longitudinal, randomized, placebo-controlled, double-blind study was to investigate the effect of calcitriol (1,25-dihydroxyvitamin D3) in the prevention of bone loss and fracture rate after HTx. METHODS: Basic therapy included 1000 mg of calcium daily and sex hormone replacement in hypogonadal patients. A total of 132 patients (111 male, 21 female; mean age: 51+/-10 years; 35+/-25 months after HTx) were randomized to 0.25 microg of calcitriol or placebo. Bone mineral density (BMD, g/cm2; T score, %) of the lumbar spine and x-rays for the assessment of vertebral fractures were performed at baseline and after 12, 24, and 36 months. Biochemical indexes of mineral metabolism were measured every 3 months. RESULTS: Overall BMD was significantly decreased after HTx (T score 87+/-13%). BMD increased continuously within the study period in the calcitriol group (1 year: 2.2+/-4.8%; 2 years: 3.9+/-5.4%; 3 years: 5.7+/-4.4%) as well as in the placebo group (1 year: 1.8+/-4.9%; 2 years: 3.7+/-6.5%; 3 years: 6.1+/-7.8%) without statistical difference between the groups. Fracture incidence was low during the study interval (1 year: 2.0%; 2 years: 3.4%; 3 years: 0%). Hypogonadism (20%) was associated with a lower BMD (78+/-12% vs. 88+/-12%; P<0.01) and a higher increase (35%) after hormone replacement in comparison to normogonadal patients. Increased intact parathyroid hormone and bone resorption markers decreased significantly during therapy. CONCLUSIONS: Calcium supplementation and sex hormone replacement in hypogonadism proved a sufficient long-term prevention therapy to improve decreased BMD and to prevent fractures after HTx. Besides immunosuppression, both concomitant hypogonadism and secondary hyperparathyroidism play a major role in the long-term bone loss and should therefore be monitored and treated adequately. Low-dose calcitriol demonstrated no significant extra benefit regarding BMD and fracture rate in the long-term period after HTx.

Interspecies comparison of rat and hamster alveolar macrophage antioxidative and oxidative capacity.

Generation of oxidants has been implicated in lung injury and disease caused by a variety of inhaled agents such as ozone, particles, and mineral fibers. Antioxidants in the pulmonary system presumably provide the initial defense against such oxidants. We designed the present study to assess the oxidative and antioxidative capacity of alveolar macrophages (AM) from rats and hamsters. These two laboratory animal species commonly used in biomedical research are well known for their disparate response to pulmonary irritants/toxicants. AM from CD rats and Syrian golden hamsters were obtained by bronchoalveolar lavage. We assessed AM antioxidant levels by measuring the catalase and superoxide dismutase (SOD) activity and the intracellular concentrations of total glutathione, ascorbic acid, and alpha-tocopherol. We determined the AM oxidative capacity by assessing the ability of AM to oxidize extracellular glutathione (GSH) and to release superoxide anions. There were no significant differences in the intracellular antioxidant levels, except for catalase activity that was significantly (p < 0.05) higher in hamster AM than in rat AM. However, AM oxidative capacity was markedly different between the two species studied. The amount of spontaneous and phorbol myristate acetate (PMA)-induced GSH oxidation was about 5-fold higher in rat AM than in hamster AM, whereas the PMA-induced superoxide anion release did not differ significantly between the two rodents. In summary, our data suggest that species variation exists between the oxidative capacity of rat and that of hamster AM. Whereas the oxidative capacity of hamster AM appears to be based mainly on the formation of reactive oxygen species, it is suggested that rat AM possess an additional oxidative system.

Body composition, bone mass and microstructural analysis in GH-transgenic mice reveals that skeletal changes are specific to bone compartment and gender.

Experimental and clinical studies suggest that high serum levels of growth hormone (GH) increase cortical but not trabecular bone. We studied body composition and bone structure in transgenic mice (MT-bGH) with systemic overexpression of GH. Body composition was examined with dual-energy X-ray absorptiometry (DXA), ashing, and chemical analysis, and the femora with DXA and micro computerized tomography. The absolute fat and bone tissue contents were significantly higher in GH transgenic mice vs controls (P < or = 0.05), but no significant difference was noted when normalizing the values to body weight. Male transgenics displayed no change in apparent (volumetric) femoral bone density, relative cortical area and trabecular bone volume fraction. Female transgenic mice demonstrated an increase in apparent femoral density and in trabecular bone volume fraction (+130%; P < or = 0.01). The mineralized tissue matrix density was decreased in male and female transgenic mice (P < or = 0.05). The results show that chronic GH excess affects trabecular bone in a gender-specific manner and that bone changes depend on the compartment investigated.

Carotene cleavage activity in bovine ovarian follicles.

Carotene cleavage activity has been demonstrated in bovine ovarian follicles by incubating cell-free homogenates from granulosa cells with 15, 15'-(14)C-beta-carotene. Enzyme activity was highly dependent on the quality of follicles studied. Highest cleavage activity was found in large, preovulatory follicles. The correlation between follicular fluid concentration of vitamin A and the conversion rate obtained with the corresponding enzyme preparations was significantly positive. No correlation, however, could be shown between cleavage activity and beta-carotene, alpha-tocopherol or cholesterol. The only form of vitamin A in follicular fluid of cattle was found to be retinol. The results support the hypothesis that a local conversion of beta-carotene into vitamin A in follicular structures is responsible for the increase of the intrafollicular concentration of vitamin A during follicular development.

Retention of cadmium in organs of the rat after a single dose of labeled cadmium-3-phytate.

Because of the low safety factor estimated for the normal content of Cd in human foods, it is important to establish the influence of food constituents such as phytate on the bioavailability of this toxic metal. We studied the retention of radioactive(109)Cd administered to rats as a chloride or a phytate in a single dose by stomach tube. The animals were fed either a normal rat chow containing 0.29% of phytate or a low phytate diet containing less than 0.1% phytate. Highly elevated levels of(109)Cd were found only in the animals that were supplied with(109)Cd as a chloride and had been fed the low phytate diet. In the animals supplied with(109)Cd as a phytate, which had also received the low phytate diet, the levels of(109)Cd in the intestine were as high as those in the group mentioned before, but the retentions in all other tissues resembled those of the respective groups fed the normal chow. The findings indicate that phytate is responsible for a considerable decrease in the intestinal absorption of Cd. Furthermore, it appears to exert an influence on the kinetics of Cd retention in the intestine.

Biological activity of 1 alpha,25-dihydroxyergocalciferol in rachitic chicks and in rats.

The bioactivity of chemically synthesized 1 alpha,25-dihydroxyergocalciferol (1,25(OH)2D2) was investigated in rachitic chicks and in vitamin D-deficient rats. In prophylactic and in curative chick assays 1,25(OH)2D2 is about 10 times less active than 1 alpha,25-dihydroxycholecalciferol (1,25(OH)2D3). Since in the same bioassay vitamin D2 is more than 80 times less active than vitamin D3, discrimination against vitamin D2 in chickens must occur at two points, before and after the formation of 1,25(OH)2D2. Receptor binding studies revealed that the chick duodenal receptor binds 1,25(OH)2D2 with the same capacity as 1,25(OH)2D3. In rats 1,25(OH)2D2 proved to have the same antirachitic activity as 1,25(OH)2D3 and might become of therapeutic interest for application in man and domestic animals if the expectations of lower toxicity are confirmed.

Biological activity of glycosides of vitamin D3 and 1 alpha-hydroxyvitamin D3.

For the first time, the biological activity of the newly synthesized glycosides of vitamin D3 and of 1 alpha(OH)D3 has been studied in rats, chickens, and Japanese quails. Glucosidation did not reduce the activity of vitamin D3. In chickens, vitamin D3 glucoside has an activity of 90% to 95% as compared to the aglycon. In rats vitamin D3 glucoside is equally active when given by intravenous or oral route. Glycosides of 1 alpha (OH)D3, however, show a lower activity in rats, chickens, and quails. 1 alpha (OH)D3 glucoside has about 10% activity of the free 1 alpha (OH)D3, while 1 alpha (OH)D3 cellobioside is without any activity in chickens. 1 alpha (OH)D3 glucoside might be of interest, due to its broader therapeutical dosage range.

Biological activity of the three mono-beta-D-glucopyranosides of 1,25-dihydroxycholecalciferol.

The biological activity of the three mono-beta-D-glucopyranosides (mono-glucosides) of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] synthesized chemically has been studied in chicks and Japanese quails. While the 1- and the 3-glucoside showed no or only little effect on serum calcium, bone weight, calcium binding protein (CaBP) or calcium deposition in the egg shell, the 25-glucoside was found to be more than half as active as the aglycone 1,25(OH)2D3. The bioactivity of this glucoside parallels a higher binding constant to the intestinal 1,25(OH)2D3 receptor compared to those of the two other glucosides.

Plasma transport and tissue distribution of [14C] beta-carotene and [3H]retinol administered orally to pigs.

The absorption, plasma transport, and tissue distribution of beta-carotene and vitamin A were studied in pigs after the oral administration of radiolabeled beta-carotene and retinol. Plasma radioactivity as well as retinol and beta-carotene were measured over a 24-h period, after which the pigs were killed. Plasma radioactivity increased within 4 h and 5 h for beta-carotene and retinol, respectively. The administration of radiolabeled retinol resulted in highest levels in the liver (83016 +/- 17614 dpm/g of tissue), followed by the kidney (5598 +/- 1309 dpm/g), the duodenum (2783 +/- 300 dpm/g), the colon (835 +/- 117 dpm/g), and the lung (756 +/- 68 dpm/g). Twenty-four hours after beta-carotene administration, tissue radioactivity distribution showed highest accumulation in the lung (22772 +/- 11997 dpm/g) and the liver (2328 +/- 694 dpm/g). The identification of the radioactive component 14C in the lung and colon indicated that the radioactivity was associated with beta-carotene only. This indicates that pigs may absorb intact beta-carotene. In other tissues such as liver, kidney, and intestine, only retinol-associated radioactivity was found after saponification of retinyl esters. The physiological importance of the unique accumulation of beta-carotene in lung tissue remains speculative.

Calcinogenic activity of vitamin D3 and vitamin D3 palmitate in rat and rabbit.

Experimental hypervitaminosis D was produced in rabbits by feeding 25,000 I.U. vitamin D3 or the corresponding amount of vitamin D3 palmitate per kg of diet. Hypercalcemia and hyperphosphatemia was accompanied by increased CaBP activity and reduced weight gain in the vitamin D3 group as well as in the vitamin D3 ester group. The degree of calcification in the aorta and in the kidney also was similar in both groups. Increasing the vitamin intake by giving 10,000 I.U. vitamin D3 or vitamin D3 palmitate per day resulted in earlier and more widespread calcific deposits. In rats, receiving 50,000 I.U. vitamins D3 or vitamin D3 palmitate per kg of diet, calcification in soft tissue was much less extensive than in rabbits. But again, no difference was seen between vitamin D3 and vitamin D3 palmitate. These results indicate, that vitamin D3 esters are not suitable as a less calcinogenic form of vitamin D3.

[Biochemical bone marrow markers and their significance in postmenopausal osteoporosis--a new method in the diagnosis of osteoporosis?]. / Biochemische Knochenmarker und deren Bedeutung bei der postmenopausalen Osteoporose--Eine neue Methode in der Osteoporosediagnostik?

This study analyzes the qualification of biochemical markers in the diagnosis of osteoporosis and evaluates the potential of a multiparametric classification of premenopausal and non-osteoporotic as well as osteoporotic postmenopausal women, which is based on biochemical marker profiles. For this evaluation data of 29 women in the age between 28-74 years were used. The classification of osteoporosis was done by the trabecular density of the lumbar spine using qCT-measurements. The biochemical markers of formation and resorption AP, bAP, OC, ucOC, PICP, PYD, DPD, NTX, BSP and vitamin K were analyzed on day 1 and 42 in all patients. For vitamin K we found significant distribution differences between non-osteoporotic and osteoporotic women (p<0.005). The crosslinks PYD and DPD showed weakly significant differences. All other parameters exhibited non-significant results. Vitamin K acted with a sensitivity of 64% and a specificity of 82%. The used multiparameter classification process improved sensitivity and specificity considerably. The parameter profiles of OC/PYD, vitamin K/PYD and vitamin K/bAP revealed the highest sensitivities with specificities of more than 82%.

[Occurrence of struma in cattle in the Czech Republic]. / Strumavorkommen bei Kälbern in der Tschechischen Republik.

In the years 1988 to 1995 among 1355 cattle examined in the frame of iodine deficiency studies in the Czech Republic 404 animals (30%) showed congenital struma. Clinical and postmortal findings are described. A monitoring of iodine content in milk showed lower values in herds with struma prevalence. The insufficient supply of iodine in these animals results from low iodine content of feed or from the goitrogenic influence of nitrate in drinking water or high content of crucifera in feed or other stress factors. An increased iodination of mineral mix in feed is highly recommended.

[Vitamin D3 poisoning--case report]. / Vitamin D3-Intoxikation--Fallbericht.

Over 650 pigs died within a couple hours in a fattening unit with approximately 3,000 fattening spaces. The pigs showed vomiting, dyspnea, kyphosis, sunken flanks, diarrhea, and polyuria. Another striking symptom of the pigs, besides the apathy, was the aphonia, due to the calcification of the vocal cords. An acute vitamin D3-intoxication was found to be the cause. The pathologic findings, especially the histologic detection of calcification processes of the soft tissues, lead to the suspect of an intoxication with a vitamin D-like substance. Between 39,000 and 196,000 IU/kg of vitamin D3 have been detected in a ready-to-use food mix. 8.8 million IU/kg of crystaline vitamin D3 were found in an open whey bag. An explanation how vitamin D came into the bag could not be clarified to this point.