PSIII-5 Confirmation of Passive Transfer of Anti-Endotoxin Igy in Neonatal Foals

Abstract

Abstract Passive immune transfer in a newborn foal is highly dependent upon the quality and concentration of immunoglobulins (Ig) in maternal colostrum, primarily IgG. Anti-endotoxin IgY derived from chicken egg yolks has been used in calves to reduce morbidity and mortality. Its use may provide additional pathogen-specific immune protection to neonatal foals, but passive transfer has not been confirmed. Therefore, the objective of this study was to quantify passive IgY transfer in neonatal foals given an egg-derived anti-endotoxin IgY supplement (Camas, Inc.) and identify effects on passive immunity. To test this, 5 neonatal foals were randomly divided into two treatment groups. Within 20 minutes after first nursing, the treated group (TRT; n = 3) was administered 40 g of the egg yolk supplement diluted in 50 mL water orally via syringe and the control group (CON; n = 2) was given isovolumetric water. At birth, physical measurements including BW, wither height (WH), hip height (HH), body length (BL), and heart girth (HG) circumference were recorded. Serum samples were collected prior to first nursing (h 0) and h 2, 6, 12, 24, 72, 168, 336 post treatment administration. Rectal temperature, heart rate, and respiration rate were recorded at all blood collection timepoints. Serum samples were analyzed for IgG, IgA, and IgY by commercial ELISA. Custom ELISA was used to identify endotoxin-specific IgY for Salmonella and E. coli at h 6. Western immunoblotting was used to confirm that passively transferred IgY was intact. Data were analyzed using PROC MIXED in SAS. Vital signs remained within normal, healthy ranges and physical measurements at birth were similar for all foals (P > 0.26). There was an effect of treatment (P = 0.05), time (P < 0.01), and treatment × time interaction (P < 0.01) for serum IgY concentrations where IgY was only detectable in TRT foals and peaked at h 6 and 12, decreasing thereafter to h 336. Concentrations of IgG and IgA increased from h 0 to 12 (P < 0.01); however, there were no effects of treatment nor treatment × time interactions (P > 0.24) for either Ig. Western immunoblotting confirmed that IgY was transferred intact and custom ELISA identified IgY specific against Salmonella and Escherichia coli. These results confirm the intact passive transfer of IgY in neonatal foals when given an IgY-infused egg yolk supplement with no negative impact on passive transfer of IgG and IgA from maternal colostrum.