Dietary Calcium and Phosphorus Amounts Affect Development and Tissue-Specific Stem Cell Characteristics in Neonatal Pigs

CAMKK2-AMPK axis endows dietary calcium and phosphorus levels with regulatory effects on lipid metabolism in weaned piglets

BACKGROUND

In the realm of swine production, optimizing body composition and reducing excessive fat accumulation is critical for enhancing both economic efficiency and meat quality. Despite the acknowledged impact of dietary calcium (Ca) and phosphorus (P) on lipid metabolism, the precise mechanisms behind their synergistic effects on fat metabolism remain elusive.

RESULTS

Research observations have shown a decreasing trend in the percentage of crude fat in carcasses with increased calcium and phosphorus content in feed. Concurrently, serum glucose concentrations significantly decreased, though differences in other lipid metabolism-related indicators were not significant across groups. Under conditions of low calcium and phosphorus, there is a significant suppression in the expression of FABPs, CD36 and PPARγ in the jejunum and ileum, leading to inhibited intestinal lipid absorption. Concurrently, this results in a marked increase in lipid accumulation in the liver. Conversely, higher levels of dietary calcium and phosphorus promoted intestinal lipid absorption and reduced liver lipid accumulation, with these changes being facilitated through the activation of the CAMKK2/AMPK signaling pathway by high-calcium-phosphorus diets. Additionally, the levels of calcium and phosphorus in the diet significantly altered the composition of liver lipids and the gut microbiota, increasing α-diversity and affecting the abundance of specific bacterial families related to lipid metabolism.

CONCLUSION

The evidence we provide indicates that the levels of calcium and phosphorus in the diet alter body fat content and lipid metabolism by modulating the response of the gut-liver axis to lipids. These effects are closely associated with the activation of the CAMKK2/AMPK signaling pathway.

mRNA Profiles of Porcine Parathyroid Glands Following Variable Phosphorus Supplies throughout Fetal and Postnatal Life

Knowledge of gene expression profiles reflecting functional features and specific responsiveness of parathyroid glands (PTGs) contributes to understanding mineral homeostasis and parathyroid function in healthy and diseased conditions. The study aims to reveal effector molecules driving the maintenance of phosphorus (P) homeostasis and parathyroid hormone (PTH) responsiveness to variable P supply throughout fetal and postnatal life. In this study, a long-term dietary intervention was performed by keeping pig offspring on distinct mineral P levels throughout fetal and postnatal life. Respective adaptation processes of P homeostasis were assessed in mRNA profiles of PTGs and serum minerals. RNA sequencing data and resulting molecular pathways of PTGs showed that the PTH abundance is very strictly controlled via e.g., PIN1, CaSR, MAfB, PLC and PKA signaling to regulate PTH expression, stability, and secretion. Additionally, the observed dietary effects on collagen expression indicate shifts in the ratio between connective tissue and parenchyma, thereby affecting cell-cell contacts as another line of PTH regulation. Taken together, the mRNA profiles of porcine PTGs reflect physiological responses in-vivo following variable dietary P supplies during fetal and postnatal life. The results serve to evaluate a long-term nutrition strategy with implications for improving the mineral balance in individuals with pathological disorders.