Dietary nitrogen and calcium modulate bone metabolism in young goats

Elfers, Kristin; Liesegang, Annette; Wilkens, Mirja R.; Breves, Gerhard; Muscher-Banse, Alexandra S.

doi:10.1016/j.jsbmb.2015.11.007

Cited by 14 publications

(9 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, cAMP was measured as an indirect assessment for PTH response as it was done in human studies [ 34 ]. Increased cAMP plasma concentrations during dietary Ca reduction indicated a physiological response to temporarily diminished plasma Ca concentrations which probably occurred during this dietary intervention to stimulate renal calcitriol synthesis [ 35 ]. In contrast, cAMP concentrations in goats on dietary N reduction were not affected, indicating a missing increase in PTH secretion in response to diminished plasma Ca concentrations [ 35 ].…”

Section: Discussionmentioning

confidence: 99%

“…Increased cAMP plasma concentrations during dietary Ca reduction indicated a physiological response to temporarily diminished plasma Ca concentrations which probably occurred during this dietary intervention to stimulate renal calcitriol synthesis [ 35 ]. In contrast, cAMP concentrations in goats on dietary N reduction were not affected, indicating a missing increase in PTH secretion in response to diminished plasma Ca concentrations [ 35 ]. A potential modulator of CDH17 RNA expression in goats in the present study could be the Ca sensing receptor (CaR), which is also expressed in caprine intestinal epithelia [ 5 ].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Expression of Tight Junction Proteins and Cadherin 17 in the Small Intestine of Young Goats Offered a Reduced N and/or Ca Diet

et al. 2016

Self Cite

View full text Add to dashboard Cite

Diets fed to ruminants should contain nitrogen (N) as low as possible to reduce feed costs and environmental pollution. Though possessing effective N-recycling mechanisms to maintain the N supply for rumen microbial protein synthesis and hence protein supply for the host, an N reduction caused substantial changes in calcium (Ca) and phosphate homeostasis in young goats including decreased intestinal transepithelial Ca absorption as reported for monogastric species. In contrast to the transcellular component of transepithelial Ca transport, the paracellular route has not been investigated in young goats. Therefore, the aim of the present study was to characterise the effects of dietary N and/or Ca reduction on paracellular transport mechanisms in young goats. Electrophysiological properties of intestinal epithelia were investigated by Ussing chamber experiments. The expression of tight junction (TJ) and adherens junction (AJ) proteins in intestinal epithelia were examined on mRNA level by qPCR and on protein level by western blot analysis. Dietary N reduction led to a segment specific increase in tissue conductances in the proximal jejunum which might be linked to concomitantly decreased expression of cadherin 17 mRNA. Expression of occludin (OCLN) and zonula occludens protein 1 was increased in mid jejunal epithelia of N reduced fed goats on mRNA and partly on protein level. Reduced dietary Ca supply resulted in a segment specific increase in claudin 2 and claudin 12 expression and decreased the expression of OCLN which might have been mediated at least in part by calcitriol. These data show that dietary N as well as Ca reduction affected expression of TJ and AJ proteins in a segment specific manner in young goats and may thus be involved in modulation of paracellular Ca permeability.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Expression of Tight Junction Proteins and Cadherin 17 in the Small Intestine of Young Goats Offered a Reduced N and/or Ca Diet

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…In Table 1 we present data from balance studies carried out in different ruminant species to illustrate that Ca and P absorption and secretion out of and into different gastrointestinal segments as well as urinary excretion are influenced by age, lactation and type of diet. There is inconsistency in the contribution of the forestomach of ruminants to overall Ca absorption (Table 1), which can partly be explained with differences in the composition of rations as mineral homeostasis interferes with other dietary factors such as dietary cation-anion difference, Mg and CP supply (Goff, 2008;Muscher and Huber, 2010;Elfers et al, 2016a;Wilkens et al, 2018). Therefore, studies using a more mechanistic approach are an important tool to enhance our knowledge.…”

Section: Introductionmentioning

confidence: 99%

Review: Regulation of gastrointestinal and renal transport of calcium and phosphorus in ruminants

Wilkens¹,

Muscher-Banse²

2020

Animal

Self Cite

View full text Add to dashboard Cite

In comparison to monogastric animals, ruminants show some peculiarities in respect to the regulation of mineral homeostasis, which can be regarded as a concerted interplay between gastrointestinal absorption, renal excretion and bone mobilisation to maintain physiological Ca and phosphate (Pi) concentrations in serum. Intestinal absorption of Ca or Pi is mediated by two general mechanisms: paracellular, passive transport dominates when luminal Ca or Pi concentrations are high and transcellular. The contribution of active transport becomes more important when dietary Ca or Pi supply is restricted or the demand increased. Both pathways are modulated directly by dietary interventions, influenced by age and regulated by endocrine factors such as 1,25-dihydroxyvitamin D3. Similar transport processes are observed in the kidney. After filtration, Ca and Pi are resorbed along the nephron. However, as urinary Ca and Pi excretion is very low in ruminants, the regulation of these renal pathways differs from that described for monogastric species, too. Furthermore, salivary secretion, as part of endogenous Pi recycling, and bone mobilisation participate in the maintenance of Ca and Pi homeostasis in ruminants. Saliva contains large amounts of Pi for buffering rumen pH and to ensure optimal conditions for the rumen microbiome. The skeleton is a major reservoir of Ca and Pi to compensate for discrepancies between demand and uptake. But alterations of the regulation of mineral homeostasis induced by other dietary factors such as a low protein diet were observed in growing ruminants. In addition, metabolic changes, for example, at the onset of lactation have pronounced effects on gastrointestinal mineral transport processes in some ruminant species. As disturbances of mineral homeostasis do not only increase the risk of the animals to develop other diseases, but are also associated with protein and energy metabolism, further research is needed to improve our knowledge of its complex regulation.

show abstract

“…The PTH increases Ca absorption and simultaneously stimulates the excretion of P i in the kidney. Due to the lack of a suitable PTH assay for goats, cyclic adenosine monophosphate (cAMP) was measured (Elfers et al, 2016) as an indirect parameter for PTH as done in human studies (Kaminsky et al, 1970). As cAMP levels showed no modulation during this feeding regime (data not shown), it was assumed that the parathyroid glands were insensitive to reduced Ca levels during a solitary N-reduced diet in young goats.…”

Section: Discussionmentioning

confidence: 99%

Modulation of renal calcium and phosphate transporting proteins by dietary nitrogen and/or calcium in young goats1

Firmenich¹,

Elfers²,

Wilkens³

et al. 2018

Journal of Animal Science

View full text Add to dashboard Cite

In young goats, a reduction in dietary nitrogen (N) had an impact on mineral homeostasis although ruminants are able to recycle N effectively due to rumino-hepatic circulation. A solitary calcium (Ca) reduction stimulated calcitriol synthesis and Ca concentrations remained unchanged, whereas a dietary N reduction led to a decrease in calcitriol, which could not be prevented by a simultaneous reduction of N and Ca. In a previous study, it was shown that a reduced dietary N intake caused a decrease in intestinal Ca absorption due to a reduction of intestinal Ca transporting proteins. As no data on the potential role of the kidneys are available, it was the aim of the present study to evaluate whether an N- and/or Ca-reduced diet had an impact on renal Ca and phosphate (Pi) transporting protein expression in young goats. The animals were divided into 4 feeding groups, each receiving an adequate N and Ca supply, a reduced N supply, a reduced Ca supply, or a combined N and Ca reduction for 6 to 9 wk. The protein expression of the renal Ca channel transient receptor potential cation channel subfamily V member 5 (TRPV5) was diminished in N-reduced fed goats (P = 0.03), whereas in Ca restricted animals, the expression remained unaltered. The mRNA and protein expression of the Ca-binding protein calbindin-D28K (CaBPD28K) and the sodium-Ca exchanger 1 (NCX1) were significantly decreased due to the N-reduced feeding (mRNA, P = 0.003; P < 0.0001; protein, P = 0.002; P = 0.02), whereas dietary Ca reduction increased the CaBPD28K and NCX1 mRNA expression (P = 0.05; P = 0.01). The mRNA and protein expression of the parathyroid hormone receptor (PTHR) decreased due to the N-reduced feeding (P = 0.02; P = 0.03). These results confirm that a reduced dietary N intake led to decreased TRPV5, CaBPD28K, PTHR, and NCX1 expression levels, contributing to low levels of calcitriol and plasma Ca. In contrast to this, sodium-phosphate cotransporter type IIa expression and plasma Pi concentration were increased during dietary N reduction, thus indicating that Pi homeostasis is modulated in a calcitriol-independent manner. In conclusion, the modulation of Ca transporting proteins expression in the kidney is not able to prevent changes in mineral homeostasis in young goats receiving an N-reduced diet.

show abstract

Dietary nitrogen and calcium modulate bone metabolism in young goats

Cited by 14 publications

References 33 publications

Expression of Tight Junction Proteins and Cadherin 17 in the Small Intestine of Young Goats Offered a Reduced N and/or Ca Diet

Expression of Tight Junction Proteins and Cadherin 17 in the Small Intestine of Young Goats Offered a Reduced N and/or Ca Diet

Review: Regulation of gastrointestinal and renal transport of calcium and phosphorus in ruminants

Modulation of renal calcium and phosphate transporting proteins by dietary nitrogen and/or calcium in young goats1

Contact Info

Product

Resources

About