Serum tumor necrosis factor alpha concentrations and clinical abnormalities in colostrum-fed and colostrum-deprived neonatal foals given endotoxin.

This research investigated how an endotoxin, specifically lipopolysaccharide (LPS), influenced the concentration of a tumor necrosis factor (TNF alpha) in colostrum-fed (CF) and colostrum-deprived (CD) newborn foals. Results indicated that LPS infusion increased serum TNF alpha levels in all foals, with larger increases and longer presence in CD foals. Although all LPS-infused foals exhibited symptoms of endotoxemia, no significant difference was found between CF and CD foals in terms of a depression index measuring clinical abnormalities.

Experiment Setup

• The study included 23 foals that were either fed colostrum (11 foals) or deprived of it (8 foals). These foals, aged 2-3 days old, were given an infusion of lipopolysaccharide (LPS), a component of the cell wall of Gram-negative bacteria.
• LPS was delivered in a saline solution in a dose of 0.5 micrograms per kilogram of body weight. As a control group, four CF and two CD foals were given the saline solution without LPS.
• Before the infusion, the concentration of Immunoglobulin G (IgG), an antibody type, and the anti-LPS IgG(T) antibody titer were measured in each foal.
• Clinical abnormalities were assessed using a depression index.

Findings

• Through a cytotoxicity bioassay, researchers confirmed that the serum TNF alpha concentration could not be detected in any preinfusion samples or in those from foals given only saline solution.
• However, serum TNF alpha levels increased in all foals given LPS, peaking between 60-90 minutes after the infusion.
• When the data was adjusted to represent mean percentage of peak serum TNF alpha concentration, it was observed that this level persisted longer in CD foals as compared to CF foals.

Implications

• Regardless of whether they were fed colostrum or not, all foals given LPS showed signs of endotoxemia, a condition resulting from the presence of endotoxins in the blood.
• No significant difference was found in the mean depression index scores (clinical abnormality measure) of CF and CD foals. Therefore, the type of feeding did not seem to affect the clinical response to LPS infusion.
• This study provides insight into the relationship between endotoxin exposure, TNF alpha production, and associated clinical signs in neonatal animals, which may have implications for managing inflammatory responses in newborn animals.