Comparative Study of the Effects of Two Dietary Sources of Vitamin D on the Bone Metabolism,Welfare and Birth Progress of Sows Fed Protein- and Phosphorus-Reduced Diets

To investigate the influence of two dietary sources of vitamin D on the vitamin D status, bone metabolism, welfare and birth progress of gestating and lactating sows, forty-nine multiparous sows were randomly assigned to one of two diets: “CON” (n = 25; 50 g vitamin D3/kg feed) and “HYD” (n = 24; 50 g 25-hydroxycholecalciferol/kg feed). The basal diets were protein- and phosphorus-reduced. The trial started on day 3 ante insemination of the sows and ended with weaning of the piglets on day 28 postpartum. Dietary supplementation of 25-hydroxycholecalciferol resulted in improved maternal vitamin D status (p < 0.001), fewer gait changes (p < 0.01) and longer standing time after feeding (day 5 ante partum; p < 0.05) compared to vitamin D3. However, the bone markers CrossLaps and osteocalcin were not affected. Overall, the present results suggest that sows fed 25-hydroxycholecalciferol instead of vitamin D3 showed improved locomotion and stance strength. However, this outcome is probably not related to altered bone metabolism. The underlying mechanisms must be investigated in further studies

Differences in peripartal plasma parameters related to calcium homeostasis of dairy sheep and goats in comparison with cows

Recently it has been demonstrated that there are differences between sheep and goats in respect to adaptation to a calcium-restricted diet. It was the aim of the present study to evaluate whether species-specific peculiarities also occur when calcium homoeostasis is challenged by lactation. Therefore, we investigated the time courses of plasma parameters related to calcium homoeostasis (calcium, phosphate, calcitriol, the bone resorption marker CrossLaps® and the bone formation marker osteocalcin) during the transition period in multiparous animals of both species and compared the results to data from a former study carried out with dairy cows. As in cows, plasma calcium and the ratio of bone formation to bone resorption decreased at parturition in goats while plasma calcitriol increased. On day 10 post partum the bone parameters of goats reached prepartum values again, which was not the case in cows. Sheep were found to experience a challenge of calcium homoeostasis already 10d before parturition, reflected by a very low ratio of bone formation to bone resorption, which was not accompanied by an increase in plasma calcitriol. Additionally, sheep and goats which had been in milk for 3 months were sampled, dried-off and sampled again 6 weeks later. In dried-off animals there were no detectable differences in parameters of bone metabolism. In conclusion we could show that the contribution of bone mobilisation to the compensation for the enhanced calcium demand due to lactation differs between the three ruminant specie

Vitamin D metabolism in growing pigs: influence of UVB irradiation and dietary vitamin D supply on calcium homeostasis, its regulation and bone metabolism

GRUPO HERMANOSCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Dietary supplementation of 25‐hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review

25‐hydroxycholecalciferol (25‐OHD3) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25‐dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25‐OHD3 instead of vitamin D3 is considered to be more efficient as plasma concentrations of 25‐OHD3 are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D3 by 25‐OHD3, some experiments indicated that 25‐OHD3 might alter physiological processes when animals are challenged, for example, by a restricted mineral supply

Differences in peripartal plasma parameters related to calcium homeostasis of dairy sheep and goats in comparison with cows

Recently it has been demonstrated that there are differences between sheep and goats in respect to adaptation to a calcium-restricted diet. It was the aim of the present study to evaluate whether species-specific peculiarities also occur when calcium homoeostasis is challenged by lactation. Therefore, we investigated the time courses of plasma parameters related to calcium homoeostasis (calcium, phosphate, calcitriol, the bone resorption marker CrossLaps® and the bone formation marker osteocalcin) during the transition period in multiparous animals of both species and compared the results to data from a former study carried out with dairy cows. As in cows, plasma calcium and the ratio of bone formation to bone resorption decreased at parturition in goats while plasma calcitriol increased. On day 10 post partum the bone parameters of goats reached prepartum values again, which was not the case in cows. Sheep were found to experience a challenge of calcium homoeostasis already 10 d before parturition, reflected by a very low ratio of bone formation to bone resorption, which was not accompanied by an increase in plasma calcitriol. Additionally, sheep and goats which had been in milk for 3 months were sampled, dried-off and sampled again 6 weeks later. In dried-off animals there were no detectable differences in parameters of bone metabolism. In conclusion we could show that the contribution of bone mobilisation to the compensation for the enhanced calcium demand due to lactation differs between the three ruminant species.</jats:p

In contrast to sheep, goats adapt to dietary calcium restriction by increasing intestinal absorption of calcium

Many studies aimed at understanding calcium homeostasis in the cow use sheep or goats as ruminant models. However, the comparability of relevant homeostatic processes between ruminant species has not been assessed. Therefore, we investigated whether the mechanisms of maintaining calcium homeostasis are similar in different ruminant species. Dietary calcium of goats was restricted along with treatment with calcitriol in a similar protocol to that in a recent study with sheep. Plasma calcium and phosphate and parameters of bone metabolism were analysed. Gastrointestinal calcium transport was characterised in vitro in Ussing chambers. The expression of apical epithelial calcium channels, calbindin-D(9K), and the basolateral plasma membrane Ca(2+)-ATPase was determined by quantitative RT-PCR and Western blot analysis. In contrast to sheep, the goats were able to compensate for low dietary calcium supply by increasing active calcium absorption in the small intestine, especially in the jejunum. As in sheep, the observed ruminal calcium transport of goats was affected neither by the calcium restricted diet nor by the calcitriol treatment, thus indicating the presence of an alternative, vitamin D-independent mechanism of calcium transport in the forestomachs. These results demonstrate that mechanisms for maintaining calcium homeostasis differ significantly between ruminant species

Dietary nitrogen and calcium modulate bone metabolism in young goats

Ruminants, possessing the rumino-hepatic circulation, are thought to cope easily with reduced dietary nitrogen (N) supply which is of economic and environmental interest to diminish N output. Nevertheless, feeding an N reduced diet to young goats resulted in a decrease in calcitriol and calcium (Ca) plasma concentrations. Although a dietary Ca reduction alone stimulated calcitriol synthesis and plasma Ca concentrations were restored, in combination with a reduced N supply this stimulating effect was abolished. Based on the important role bone tissue plays in maintaining Ca homeostasis, aim of the present study was to determine effects of an N reduced diet with or without a concomitant Ca reduction on bone metabolism in young goats. A dietary N reduction alone resulted in a significant rise in plasma concentrations of bone resorption marker C-terminal telopeptide of type I collagen (CTX) and bone formation marker osteocalcin (OC), while reduced intake of Ca as well as the combination of both dietary interventions increased bone markers only slightly. Bone mineral content and bone mineral density of metatarsi were decreased by reduced N intake, while Ca and phosphorus (P) content of dried bones remained unaffected. In contrast, a dietary Ca reduction alone led to decreased Ca and P content of dried bones. From these data it can be concluded that a dietary N reduction alone or in combination with a reduced dietary Ca supply modulated bone metabolism in young goats

Blood leukocyte composition and function in periparturient ewes kept on different dietary magnesium supply

BACKGROUND: Transition period (TP) is characterised by physiological and metabolic changes contributing to immunodysregulation. Since knowledge about this period in sheep is scarce, we analysed changes in selected immune variables during the TP in ewes and whether dietary magnesium (Mg) supplementation could modulate these immune variables. Pregnant ewes (2nd and 3rd lactation) were divided into a control group (CONT, n = 9) and a Mg group (MAG, n = 10) supplemented with Mg oxide resulting in a daily Mg intake of approximately 0.30 and 0.38% (MAG) of dry matter during ante- (a.p.) and post-partum (p.p.) periods, respectively. Blood samples were collected between days (d) 30 a.p. and d 30 p.p.. Whole blood neutrophil phagocytic activity, monocyte subset (classical cM, intermediate intM, non-classical ncM) composition and the proliferative capacity of lymphocytes were determined flow cytometrically. At d 14 a.p., all ewes were vaccinated against Mycobacterium avium subsp. paratuberculosis (MAP). RESULTS: Both groups showed a sharp increase in the total leukocyte counts (TLC) and neutrophil counts (P &amp;lt; 0.0001), at d 1 p.p., while, monocytes and their subpopulations displayed the highest values at d 30 p.p. (P ≤ 0.05). At d 1 p.p. the neutrophil phagocytic activity was higher (P &amp;lt; 0.05) in MAG ewes. Throughout the TP, the proliferative response of CD4+ cells was significantly higher in the MAG group (P &amp;lt; 0.05). Ewes in both groups responded with an increase in the TLC, neutrophil numbers (P ≤ 0.05) and ncM (P &amp;lt; 0.001) 24 h post vaccination, whereas monocytes and cM dropped in numbers (P ≤ 0.05). Numbers of intM only increased in MAG ewes (P &amp;lt; 0.05), whereas lymphocyte numbers decreased (P &amp;lt; 0.01). Mg supplementation did not affect the significant increase in MAP-specific antibodies at d 7 and 21 post vaccination. Total Mg and Ca serum levels did not show any differences between the two groups. CONCLUSION: Whereas TP-associated fluctuations in blood leukocyte numbers are not influenced by Mg supplementation, neutrophil phagocytic activity, the proliferative capacity of CD4+ cells and the cellular response within 24 h after a vaccination are subject to modulation

Is the metabolism of 25-hydroxyvitamin D(3) age-dependent in dairy cows?

It has recently been demonstrated that prepartum administered 25-hydroxyvitamin D3 (25-OHD3) is a promising candidate to assist the maintenance of peripartal calcium homeostasis in dairy cows. Since the incidence of peripartal hypocalcemia and the reported beneficial effects of the treatment are both associated with the lactation number, we investigated pharmacokinetic aspects of 25-OHD3 related to the age of dairy cows. The daily oral administration of 3mg 25-OHD3 in rapeseed oil as well as a treatment with 4 and 6mg included in the feed during the last eight to ten days of gestation resulted in linear dosage- and age-dependent increases in plasma 25-OHD3. After parturition the administration was stopped and blood samples were taken to calculate the plasma half-life. Irrespective of the supplemented dosage, cows starting the 2nd lactation showed a significantly longer plasma half-life of 25-OHD3 than cows starting the 3rd or higher lactation. Age-dependent differences in the increase of plasma 25-OHD3 could already be found before parturition when calcium homeostasis was not yet significantly challenged. Additionally, no correlations between plasma half-life of 25-OHD3 and 1,25-dihydroxyvitamin D3, PTH or the bone resorption marker CrossLaps were observed after parturition. Thus we conclude that the influence of the lactation number on the pharmacokinetics of 25-OHD3 is related directly to the age of the cows. This article is part of a Special Issue entitled ´Vitamin D Workshop´.Fil: Wilkens, Mirja. University of Veterinary Medicine Hannover. Department of Physiology; AlemaniaFil: Cohrs, Imke. University of Veterinary Medicine Hannover. Department of Physiology; AlemaniaFil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires.. Facultad de Ciencias Veterinarias; ArgentinaFil: Fraser, David R.. University of Sydney. Faculty of Veterinary Science; AustraliaFil: Olszewski, Katharina. DSM Nutritional Products; SuizaFil: Schoeder, Bernd. University of Veterinary Medicine Hannover. Department of Physiology; AlemaniaFil: Breves, Gerhard. University of Veterinary Medicine Hannover. Department of Physiology; Alemani