Characterization of lyophilized equine colostrum

Abstract

Colostrum is the first milk secretion at birth and is indispensable for the equine newborn. In addition to being the only natural source of immunoglobulins (Igs) available, it has excellent nutritional importance in helping the gastrointestinal system's maturation. Thus, foals need to ingest maternal colostrum in the first hours of life to acquire immunity so that failure of passive transfer of immunity (FPTI) does not occur. The quality of the colostrum supplied to the animals must be evaluated, and innovation in its storage methods would greatly benefit management. Lyophilization is a differentiated process of dehydration that retains a large concentration of colostrum immunoglobulins. The only lyophilized colostrum for foals is based on bovine colostrum) This study aimed to compare the IgG concentration and the physicochemical characteristics of frozen equine colostrum after the lyophilization process. Thirty-one pregnant mares were used. Colostrum samples were collected manually from both mammary glands immediately after delivery. The udder was cleaned with 70% alcohol solution to avoid sample contamination. About 20 mL of colostrum were collected, and the first two jets were discarded. The IgG concentration of frozen and lyophilized colostrum was determined by the Simple Radial Immunodiffusion method (IDRS) and also, indirectly, by Brix refractometry. The samples' physical-chemical composition (pH, total protein (TP),fat, lactose, salts, total solids (TS), and density) was evaluated,and the lyophilized colostrum reconstitution test was performed. The ways of preserving colostrum were compared using a t-test at 5% probability. Pearson correlations were utilized between variables with Sisvar®, version 5.7 statistical software. No significant differences were seen in the measurements of IgG, fat, lactose, salts, TS, density, and pH before and after lyophilization. No difference was seen in the IgG concentration measured by IDRS (frozen 30.5 g/L vs lyophilized 28.5 g/L). A strong positive correlation was observed between colostrum density and IgG concentration by IDRS (r = 0.76) and between Brix and IgG concentration by IDRS (r= 0.77). In the reconstitution test, lyophilized colostrum was efficiently rehydrated in water, with total dilution, and remained stable. The results suggest that lyophilization can be an alternative for conservation of colostrum from mares, because it is a very efficient process for the retention of the physicochemical characteristics of the product, with no significant loss of IgG concentration. In addition, it is easy to reconstitute, can be preserved for a long period without the need for refrigeration and easily transported. This research should be expanded to make an innovative equine product available. This will facilitate the management of newborn foals and help to reduce the rates of failure of passive immunity transfer.