Concentration of sialyloligosaccharides in colostrum and milk from two Italian goat breeds

Milk oligosaccharides provide numerous important biological functions, such as prevention of pathogen binding to the intestinal epithelium and nutritive source for beneficial bacteria. Aim of this work was to study the oligosaccharides profile and content in colostrum and milk in two Italian goat breeds. Individual samples of colostrum and milk were obtained from 20 Maltese (M) and 15 Garganica goats (G). Each goat provided one sample at the following stages: Colostrum 0h (immediately after kidding); Colostrum 24h; early milk (day 7th) and mature milk (day 30th and 90th). The samples, from the morning milking, were immediately frozen at - 20°C. The most representative sialyc acids of goat milk, that are 3’-sialyllactose (3’SL), 6’- sialyllactose (6’SL) and disialyllactose (DSL) content (mg/L), were evaluated using HPAECPAD. Statistical analysis was carried out by one-way ANOVA (SAS 9.1.3). The differences among breeds were analysed by Duncan multiple range test. The results clearly showed a breed effect at each lactation stage on the oligosaccharides content. G breed showed in colostrum the highest content of 3’-SL both at 0h (253.9 vs. 201.3 mg/L) and 24h (328.5 vs. 249 mg/L) and the highest content of 6’-SL both at 0h (174.3 vs. 136.9 mg/L) and 24h (200.9 vs. 144.1 mg/L). DSL content was the highest at 0h (197.9 vs. 104.9), and the lowest one at 24h (126.4 vs. 228.1 mg/L). Also in early milk, G breed showed the highest content of 3’-SL and 6’-SL, but the lowest content of DSL (94.5 vs. 153.2 mg/L). The concentration of 3’-SL decreased significantly (P < 0.01) and progressively from Colostrum-24h to mature milk (90 d) in G breed, while in M breed decreased from Colostrum-24h to early milk (7 d) and after increased progressively in mature milk (30 and 90 d). The content of 6’-SL decreased progressively from colostrum-0h to 30 d and increased from 30 to 90 d in both breeds. The DSL content decreased progressively from Colostrum-0h to mature milk (90 d) in G breed; contrarily, in M breed it decreased from colostrum-24h to 30 d and after increased at 90 d. The content of sialyloligosaccharides significantly changed during lactation’s stages between the two goat breeds, where G breed showed meanly highest values. Considering the oligosaccharides profile, similar to human milk’s, goat milk may represent a chance for use in the infant milk formula.