Physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed supplement

OBJECTIVE: This study explored the physico-chemical properties of late-incubation egg amniotic fluid and a potential in ovo feed (IOF) supplement. METHODS: Amniotic fluid was collected from broiler breeders (Ross 308, 51 weeks and Cobb 500, 35 weeks) on day 17 after incubation. A mixture of high-quality soy protein supplement – Hamlet Protein AviStart (HPA) was serially diluted in MilliQ water to obtain solutions ranging from 150 to 9.375 mg/mL. The mixtures were heat-treated (0, 30, 60 minutes) in a waterbath (80°C) and then centrifuged to obtain supernatants. The amniotic fluid and HPA supernatants were analysed for their physico-chemical properties. RESULTS: Only viscosity and K(+) were significantly (p<0.05) different in both strains. Of all essential amino acids, leucine and lysine were in the highest concentration in both strains. The osmolality, viscosity and pCO(2) of the supernatants decreased (p<0.05) with decreasing HPA concentration. Heat treatment significantly (p<0.05) affected osmolality, pH, and pCO(2), of the supernatants. The interactions between HPA concentration and heat treatment were significant with regards to osmolality (p<0.01), pH (p<0.01), pCO(2) (p<0.05), glucose (p<0.05), lactate (p<0.01) and acid-base status (p<0.01) of HPA solutions. The Ca(2+), K(+), glucose, and lactate increased with increasing concentration of HPA solution. The protein content of HPA solutions decreased (p<0.05) with reduced HPA solution concentrations. The supernatant from 150 mg/mL HPA solution was richest in glutamic acid, aspartic acid, arginine and lysine. Amino acids concentrations were reduced (p<0.05) with each serial dilution but increased with longer heating. CONCLUSION: The values obtained in the primary solution (highest concentration) are close to the profiles of high-protein ingredients. This supplement, as a solution, hence, may be suitable for use as an IOF supplement and should be tested for this potential.