Scientists studied how chickens’ bodies manage an important mineral called phosphorus as they grow older and begin laying eggs. They looked at two different chicken breeds and tested whether adding extra phosphorus to their food made a difference. The research found that as chickens aged, their bodies changed how they controlled phosphorus levels, and these changes were different depending on the chicken breed. Interestingly, adding more phosphorus to the diet didn’t seem to change how the chickens’ bodies responded. This study helps us understand how chickens naturally balance minerals in their bodies during different life stages.

The Quick Take

  • What they studied: How chickens’ bodies manage phosphorus (a mineral important for bones and egg production) as they get older and start laying eggs, and whether adding extra phosphorus to their food changes anything.
  • Who participated: Two different commercial chicken breeds (Lohmann Brown-Classic and LSL-Classic) at two different ages (15-week-old and 20-week-old chickens). Some chickens received extra phosphorus in their food, while others did not.
  • Key finding: As chickens aged, their bodies shifted how they controlled phosphorus levels. This shift was different between the two chicken breeds. Surprisingly, adding extra phosphorus to the food did not significantly change how the chickens’ bodies managed this mineral.
  • What it means for you: If you raise chickens or work in poultry farming, this suggests that the standard amount of phosphorus supplementation in chicken feed may be appropriate, and adding more may not provide additional benefits. However, this research is specific to chickens and doesn’t directly apply to human nutrition.

The Research Details

Researchers took two popular breeds of laying hens and divided them into groups. Some groups received standard chicken feed, while others received the same feed with extra phosphorus added. They studied the chickens at two different ages: 15 weeks old (before they started laying eggs) and 20 weeks old (after they started laying eggs). After four weeks on their assigned diets, the chickens were humanely euthanized, and scientists examined how certain genes and proteins related to phosphorus control were expressed in different organs like bones, liver, and kidneys. They used advanced laboratory techniques to measure these expressions and then looked for patterns and connections with other mineral-related measurements in the chickens’ blood.

Understanding how chickens naturally regulate phosphorus is important because phosphorus is essential for strong bones and proper egg production. By studying how different breeds and ages handle phosphorus, researchers can determine if current feeding practices are optimal. This could help farmers make better decisions about feed supplementation, potentially reducing unnecessary additives while maintaining chicken health and productivity.

This study examined actual biological samples from chickens using established laboratory methods (quantitative real-time PCR and western blotting), which are reliable techniques for measuring gene and protein expression. The researchers looked at multiple organs and made statistical comparisons between groups. However, the study focused specifically on chickens and the findings may not apply to other species or to humans. The exact number of chickens studied was not specified in the abstract, which limits our ability to fully assess the study’s statistical power.

What the Results Show

The most important finding was that age significantly affected how chickens’ bodies controlled phosphorus. Older chickens (24 weeks old) showed lower expression of a key regulatory protein called FGF23 in their bones but higher expression in their livers compared to younger chickens (19 weeks old). Another important protein called αKlotho showed higher expression in bones, liver, and kidneys of older chickens. These changes appeared to be connected to when chickens started laying eggs. The two chicken breeds also responded differently, with LSL hens showing higher αKlotho expression in their livers regardless of age or diet. Interestingly, the amount of phosphorus in the diet did not significantly change how these regulatory proteins were expressed, suggesting that the chickens’ bodies maintained phosphorus control similarly whether they received extra phosphorus or not.

The researchers found important connections between where these regulatory proteins were expressed and the actual phosphorus levels in the chickens’ blood. When FGF23 was highly expressed in bones, blood phosphorus levels tended to be higher. When FGF23 was highly expressed in the liver, blood phosphorus levels tended to be lower. These opposite patterns suggest that bones and livers may play different roles in controlling phosphorus. The study also found that bone FGF23 expression was negatively associated with calcitriol (an active form of vitamin D), meaning when one was high, the other tended to be low.

This research adds new information about how chickens control phosphorus, which has traditionally been thought to be regulated mainly by vitamin D and parathyroid hormone. The discovery that FGF23 and αKlotho play roles in chicken phosphorus regulation is relatively new, as these factors have been well-studied in mammals but less so in birds. The finding that dietary phosphorus supplementation doesn’t significantly affect these regulatory proteins challenges the common practice of routinely adding extra phosphorus to laying hen feed, suggesting that current standard feeding practices may already provide adequate phosphorus.

The study was conducted only in chickens, so the findings cannot be directly applied to humans or other animals. The exact sample size was not clearly stated, making it difficult to assess whether the study had enough chickens to detect all important differences. The study only looked at two chicken breeds, so results may not apply to all laying hen varieties. The research examined chickens at only two time points, so it’s unclear how phosphorus regulation changes gradually over time. Additionally, the study looked at gene and protein expression in specific organs but didn’t measure actual phosphorus absorption or utilization, which would provide a more complete picture of how the chickens’ bodies were actually using phosphorus.

The Bottom Line

For poultry farmers: Current standard phosphorus supplementation in laying hen feed appears to be adequate based on this research. Adding extra phosphorus beyond standard recommendations may not provide additional benefits. However, this is preliminary evidence, and farmers should consult with poultry nutritionists before making changes to feeding practices. Confidence level: Moderate (based on one study with limited sample size information).

Poultry farmers and feed manufacturers should pay attention to this research, as it suggests that current phosphorus supplementation practices may be appropriate. Poultry nutritionists and veterinarians may find this useful for making feeding recommendations. This research does not apply to human nutrition or health. Pet bird owners should not assume these findings apply to their birds, as the study focused on commercial laying hens.

The changes in how chickens’ bodies controlled phosphorus occurred gradually over the 4-week study period and appeared to be related to the natural aging process and the onset of egg-laying. Farmers would not expect to see immediate changes from adjusting phosphorus supplementation, as the body’s regulatory systems adapt gradually over weeks.

Want to Apply This Research?

  • If you manage a poultry operation, track weekly feed phosphorus levels and monitor egg production quality and quantity. Record any changes in shell quality, bone strength indicators (if applicable), or hen health metrics to see if current phosphorus levels are adequate.
  • Review your current feed supplementation practices. If you’re adding extra phosphorus beyond standard recommendations, consider whether this is necessary based on your hens’ performance. Consult with a poultry nutritionist to ensure your phosphorus levels match your specific flock’s needs rather than automatically supplementing.
  • Establish a baseline of your current phosphorus supplementation and track hen health, egg production, and egg quality over 8-12 weeks. Monitor for any changes in bone health (if you can assess this) and overall flock performance. Compare results before and after any adjustments to supplementation to determine what works best for your specific operation.

This research is specific to commercial laying hen breeds and does not apply to human nutrition or health. The findings suggest that current phosphorus supplementation practices in poultry feed may be adequate, but individual flock needs may vary. Poultry farmers should consult with veterinarians or poultry nutritionists before making significant changes to feed formulations. This study is preliminary research, and more studies are needed to fully understand phosphorus regulation in chickens. Always follow your local regulations and best practices for poultry care and nutrition.