Lyophilization as an alternative for conservation of equine plasma as a source of immunoglobulin G for neonatal foals

Providing plasma with immunoglobulins is essential for the health of foals with failure of passive transfer of immunity. The use of lyophilized plasma (LP) offers a simple and affordable option in terms of transportation and storage. This study aimed to measure the concentrations of immunoglobulin G (IgG), total protein (TP), and total solids (TS) in fresh equine plasma before and after lyophilization. Plasma was collected from six healthy male horses. The samples underwent freeze-drying and were reconstituted in deionized water to their original volume. The concentrations of IgG in both fresh and reconstituted LP were determined by simple radial immunodiffusion and TS and TP concentrations measured using refractometry. Results indicated that the IgG concentration in fresh plasma (8.9 ± 3.2 g/L) was not different from LP (7.1 ± 2.2 g/L; P > 0.05). The TP concentration in fresh plasma was 6.6 ± 0.5 g/dL, which decreased to 5.7 ± 0.2 g/dL after lyophilization (P < 0.05). The TS of fresh plasma were 7.5 ± 0.8 %, and also lower in LP 6.3 ± 0.5 % (P < 0.05). The findings revealed that the lyophilization process preserves IgG concentration with small losses in TS and TP upon reconstitution. The research supports the potential of lyophilized equine plasma as a promising treatment option, with future efforts focused on optimizing the product, validating its efficacy and stability through clinical trials, and developing practical packaging solutions for use in the equine industry.