Major constituents, leptin, and non-protein nitrogen compounds in mares’ colostrum and milk.

This study investigates the concentration and changes in key substances found in mares’ colostrum and milk, focusing particularly on leptin and non-protein nitrogen compounds. Results suggest significant variations in major constituent levels between pre-suckle colostrum and later samples, with leptin highest in initial colostrum, reducing sharply after birth and more gradually thereafter. Mares’ milk, due to its constituents, may be considered a functional food.

Research Methodology and Observations

• The research was conducted using five Haflinger mares. Colostrum and milk were collected at specified intervals postpartum (0 hours pre-suckle, 6 hours post-suckle, and 12, 24, 48, 72, and 96 hours postpartum).
• Investigation of total solids, protein, fat, lactose, calculated gross energy content, leptin, and various non-protein nitrogen elements (urea, alpha-amino nitrogen, creatinine, and allantoin) was carried out on the collected samples.

Findings and Interpretation

• Significant variations were observed in the concentration of major components between pre-suckle colostrum and milk samples collected thereafter.
  • Leptin, a hormone commonly associated with body weight management, was found in the highest concentrations (9 ng x mL(-1) of immunoreactive human equivalent HE +/- 0.48 ng x mL(-1), SEM) in pre-suckle colostrum. It declined sharply 6 hours after childbirth and decreased more slowly henceforth.
  • Urea, another nitrogen compound, remained more or less constant around 5.0 mM.
  • Alpha-amino N concentrations were observed to increase over the period of observation, while concentrations of creatinine and allantoin, other non-protein nitrogen compounds, decreased.
• These shifts in constituent levels, particularly the high levels of leptin in pre-suckle colostrum, suggest that mares’ milk can be classified as a functional food. Functional foods are those that offer health benefits beyond basic nutrition, affecting the normal functions of the human body in a way that either improves general health, reduces the risk of disease, or enhances well-being.