Colostrum protein digestion in newborn lambs

Area of Science:

• Animal Science
• Biochemistry
• Digestive Physiology

Background:

• Colostrum is crucial for newborn lamb nutrition, providing essential proteins like immunoglobulins (IgG1).
• Understanding colostral protein digestion efficiency is vital for neonatal lamb development and health.

Purpose of the Study:

• To investigate the digestion efficiency of colostral proteins in newborn lambs.
• To compare the digestion and absorption of colostral proteins versus bovine milk proteins.

Main Methods:

• Nine newborn lambs were fed bovine colostrum, with comparisons to unfed lambs and milk-fed lambs.
• Digesta, gastrointestinal tissues, blood, and urine were analyzed for protein and peptide composition (IgG1, beta-lactoglobulin, alpha-lactalbumin, caseins) at set time points post-feeding.
• Abomasal emptying rates and amino acid availability were quantified.

Main Results:

• Lambs fed colostrum exhibited higher ingested protein amounts and faster abomasal emptying compared to milk-fed lambs.
• Alpha-lactalbumin was rapidly degraded, while beta-lactoglobulin and IgG1 showed lower sensitivity to proteases.
• Within 4 hours, 35% of dietary amino acids from colostrum were available for metabolism, versus 54% from milk, with IgG1 being a significant source in colostrum-fed lambs.

Conclusions:

• Colostral protein digestion in newborn lambs is selective, with varying sensitivities of different protein fractions to gastrointestinal proteases.
• While abomasal emptying is faster with colostrum, the overall amino acid availability within the initial hours is lower compared to milk, partly due to the slower digestion of immunoglobulins.
• These findings highlight the distinct nutritional dynamics of colostrum versus milk in early lamb development.