Growth Hormone Secretion Patterns in German Landrace (DL) Fetuses and Piglets Compared to DL Piglets with Inherited 1,25-Dihydroxyvitamin D3 Deficiency.

The regulation of growth hormone (GH) release during prenatal development and during early postnatal life is not entirely clarified. In this study plasma GH concentrations in pigs with inherited pseudo vitamin D deficiency type I (PDDR-I), which regularly show growth retardation, were compared during ontogeny with unaffected pigs of the same breed (German Landrace, DL) as control. Plasma GH concentrations were measured in plasma of chronically catheterized fetuses (beginning on day 101 after mating or after artificial insemination) and in piglets (day 37 postpartum (p.p.)-day 42 p.p.) of both lines. A growth curve beginning at day 7 p.p. was recorded for both lines. The relative amount of GH receptor (GHR) mRNA in liver was quantified by competitive reverse transcription polymerase chain reaction in piglets at day 42 p.p. A trend for higher GH concentrations was observed in PDDR-I fetuses (p < 0.1). In PDDR-I piglets compared to DL piglets higher plasma GH values (p < 0.01), were observed despite lower body weight. The relative quantity of GHR mRNA in liver was not significantly different between the two lines. Piglets with an inherited defect of vitamin D synthesis showed higher GH concentrations. A hormonal imprinting by low 1,25(OH)2D3 could be one reason for our observations and should be analysed in detail in future.

Effects of pharmacological doses of Vitamin D3 on mineral balance and profiles of plasma Vitamin D3 metabolites in horses.

Metabolism and functions of Vitamin D in horses differ from those in humans, pigs and rats. In horses, calcidiol and calcitriol concentrations in blood plasma are remarkably low (<10 nmol L(-1); 20-40 pmol L(-1), respectively). When a toxic amount of Vitamin D(3) is administered, the responsiveness of calcium and calcitriol concentrations in blood plasma is much reduced compared to the other domestic animal species but inorganic phosphate (Pi) response is much more marked, leading to an increase of the Ca x Pi product. Also, soft tissue calcifications have been observed to develop in horses during Vitamin D(3) intoxication. It was suggested that the elevation of the Ca x Pi product may play a causative role in this calcification process. To test this assumption, two horses were treated with 40,000 IU kg(-1) of Vitamin D(3) whilst dietary uptake of Ca and Pi was restricted to prevent or to diminish the increase of the Ca x Pi product. Distribution, number and severity of calcification centres were considerably less in these horses than in the control animals of a previous experiment which had received the same amount of Vitamin D(3) but where Ca and Pi intake was not restricted. It appears from these findings that in horses, the increase of the Ca x Pi product in blood plasma during a Vitamin D intoxication contributes to the soft tissue calcifications. It is further concluded that in the event of a Vitamin D intoxication, it is recommended to restrict the Ca and Pi uptake immediately. The authors believe that this may help to prevent or at least diminish soft tissue calcifications which are often fatal to the horse due to nephrocalcinosis.

Dietary additions of lactose, casein and soy protein exerted only moderate effects on calcium homeostasis in calcitriol deficient piglets.

It has been reported from rats and mice that blood and bone calcium can be normalised in the absence of Vitamin D hormone or its receptor by dietary means. It was the aim of this study to test, whether a similar result can be obtained with pigs. Piglets with inherited calcitriol deficiency were fed with high calcium and Pi diets and supplemented with soy protein or casein and lactose or corn starch, which have been shown to normalise plasma and bone calcium in Vitamin D deficient rats and in mice. In the calcitriol deficient piglets none of the diets was capable to prevent the development of hypocalcemia. However, additions of lactose and soy protein improved somewhat plasma calcium (P < 0.001). Feeding of soy protein also had a significant positive effect on plasma phosphate concentration (P < 0.001). The study shows that in contrast to rats, calcitriol is essential for maintaining a normal plasma and bone calcium status. Responses of this type, when obtained with rats or mice can probably not directly be transferred to pigs and perhaps also not to humans.

[Concentrations of carnitine and further biochemical parameters in the blood serum of healthy dairy cows and cows with abomasal displacement (dislocatio abomasi) and puerperal disorders]. / Carnitinkonzentrationen und weitere biochemische Parameter im Blutserum von gesunden Milchkühen und Kühen mit Dislocatio abomasi sowie Puerperalstörungen.

It was the aim of this study to compare the concentrations of total (TC) and free L-carnitine (FC) in blood serum of different groups of lactating cows. The animals were allotted into three groups, a) control animals (N = 11), b) cows with abomasal displacement (AD) (N = 5) and c) cows with puerperal disorders (PD) (N = 5). TC and FC were measured with an radioenzymatic assay. Blood samples were collected from 5 to 0 d before parturition (a. p.) and from 0 to 28 d after parturition (p. p.). It was of interest to examine whether L-carnitine might be limiting under certain conditions of metabolic stress which are typical for high yielding lactating cows. Concentrations of TC and FC (mumol/l) in control cows before and after parturition were 10.0* and 8.6* and 6.0-8.9 and 3.7-4.9, respectively. The corresponding TC and FC values for cows with AD were 19.6* and 8.9* and 10.5-20.7 and 4.8-6.9, respectively. Cows with PD showed TC and FC concentrations a. p. and p. p. of 15.7* and 9.2* and 10.3-13.0 and 4.8-6.3, h other puerperal disorders PD respectively (* only one value). TC and FC concentrations in serum of normal cows were higher before than after parturition. Cows, which developed post partal puerperal disorders had a higher prepartum concentrations of TC and CE, on the other hand, serum concentrations of FC was lower. Post partum cows with metabolic disorders showed higher CE levels than control animals. Cows which developed DA had significantly higher concentrations of TC and CE in serum only on d 7 p.p. than animals with other PD. It appeared that increased fat mobilization was regularly associated with responsive increases of CE concentrations in blood serum.