Work published in Poultry Science describes the testing of a hypothesis that the in-ovo injection of biological buffers may reinforce the buffering capacity of albumen, thereby withstanding the increase in albumen pH during storage and improving hatchability and chick quality in long-term stored eggs.

Researchers based in Iran found that certain pre-storage in-ovo injections improved hatchability in eggs stored long-term.

A. Akhlaghi from Shiraz University in Iran and co-authors there and at Gorgan University of Agricultural Science and Natural Resources, University of Mohaghegh Ardabili and Sari Agricultural Sciences and Natural Resources University as well as Institute of Tropical Agriculture, University Putra Malaysia report that hatching eggs (n=2,420) were randomly assigned to 11 treatment groups (4 replicates of 55 eggs each).

On day 1, they were injected with distilled water, 25 or 50mM HEPES (H₂₅ and H₅₀), Bicine (B₂₅ and B₅₀), Tris (T₂₅ and T₅₀), and Bis-Tris-propane (BTP₂₅ and BTP₅₀) solutions or were not injected (intact: control; or pricked with a needle: N).

The eggs were then stored for 14 days, during which the egg internal characteristics were evaluated at 1, 2, 3, 4, 5, 8, and 13 days of storage (n=924 in total) and the remaining eggs (n=1,496) were incubated.

A decrease in albumen pH was found for H₂₅, H₅₀, B₅₀ and BTP₂₅ groups from two to five days post-injection. Eggs receiving H₂₅, H₅₀, and B₅₀ recorded a higher albumen index (at 13 days of storage) and Haugh unit (between 8 and 13 days of storage) than the control.

Akhlaghi comments that interestingly, the hatchability of fertile eggs was influenced by the treatment effect (P=0.0001) where the eggs receiving H₂₅ (88.3 per cent), H₅₀ (88.9 per cent), B₅₀ (88.4 per cent) and BTP₂₅ (87.6 per cent) recorded higher values than that of control (82.1 per cent), associated with a decreased early embryonic mortality rate (P<0.0001).

In-ovo injection of Tris buffer, however, profoundly decreased the hatchability (47.2 and 29.0 per cent for T25 and T50, respectively) and percentage of first-grade chicks (67.5 and 63.6 per cent for T25 and T50, respectively) compared with the control (90.1 per cent).

The researchers concluded that pre-storage in-ovo injection of H₂₅, H₅₀, B₅₀ and BTP₂₅ improved hatchability in long-term stored eggs in which a decreased albumen pH during the days two to five of storage period might be involved.

Reference

^{Akhlaghi, A., Y.J. Ahangari, S.R. Hashemi, B. Navidshad, Z.A. Pirsaraei, H. Deldar, M.R. Ebrahimi, M. Dadpasand, H. Atashi and J.B. Liang. 2013. Prestorage in ovo injection of biological buffers: An approach to improve hatchability in long-term stored eggs. Poult. Sci. 92(4):874-881. doi: 10.3382/ps.2012-02610}