[Physiology of intestinal absorption of phosphorus in animals].

The research shows that the digestion and absorption of inorganic phosphorus (P) in mammals happens primarily in the duodenum and jejunum, part of the small intestine, with variations in the absorption site for horses and ruminants. The study also mentions that key factors such as endocrine and nutritional elements influence this process and suggests further studies to help decrease the cost of phosphorus supplementation in farm animals.

Intestinal absorption of Phosphorus

• The researchers in this study discuss the absorption of inorganic phosphorus (P), a nutrient essential for the survival and health of organisms.
• The primary site of phosphorus absorption in most mammals (including humans) is found to be the duodenum and jejunum, two parts of the small intestine. However, variations are observed in specific species.
• In horses, some phosphorus absorption also happens from the large intestine. In ruminant animals, typically herbivores like cows and sheep, some absorption occurs in the forestomachs, which are the rumen, reticulum, and omasum sections of the stomach. These habitats have not been previously associated with nutrient absorption.

Structures Involved in Phosphorus Absorption

• The exact structural elements in the intestines, involved in the absorption process still remain to be definitively identified.
• The researchers speculate on a ‘phosphate-sodium carrier’ at the brush border of the enterocytes, the absorptive cells in the lining of the intestines and suggest future explorations in this regard.

Role of Endocrine and Nutritional Factors

• A key finding of the study is the influence of endocrine and nutritional factors on phosphorus absorption.
• Endocrine factors such as hormones like calcitriol and triiodothyronine, are found to modulate phosphorus absorption.
• Nutritional factors, specifically dietary minerals and the chemical form of phosphorus also play a role in this process.

Need for Further Research

• The research points to gaps in current understanding about phosphorus metabolism, specifically about the regulation of phosphorus secretion in saliva and its intestinal absorption, particularly in ruminants.
• This study also calls for better understanding of the organism’s adaptation to diets either high or low in phosphorus.
• Filling these knowledge gaps would potentially contribute to decreasing the cost of phosphorus supplementation in farm animals, an aspect of significant economic interests.