The acute phase protein response to intramammary infection in water buffalo (Bubalus bubalis)

Acute phase proteins are a group of serum proteins that change their concentration in animals following infection, inflammation or stress. Serum amyloid A (SAA) and α1-acid glycoprotein (AGP) are regarded as acute phase proteins in bovine, and their concentrations increase in blood and milk from cows during mastitis. In this study we determined the concentration of SAA and AGP in serum and milk collected from healthy water buffaloes (Bubalus bubalis) and buffaloes with intramammary infection (IMI). The nucleotide sequences of SAA and AGP were determined by cDNA sequencing and showed homology of 9% and 95% respectively with bovine one. The concentration of SAA and AGP in serum (34 samples) or milk (134 samples) were analyzed by established immunologic methods utilizwed for bovine, after validation of the cross-reactivity of the antibodies included in the kit with the buffalo proteins. The concentration of serum and milk AGP was under the detection limit of the kit, and was therefore undetectable. SAA cut-off values were assumed to be 4.1mg/l in serum and 1.4 mg/l in milk as in bovine. Data collected showed that the concentration of serum from all of the buffaloes with IMI (17.8 mg/l ± 9.5 s.e., p<0.001). results in milk showed that in healthy buffaloes the protein was not detectable, but when IMI is present SAA was detectable in all samples with mean concentration of 4.1 mg/l ± 0.37 s.e. (p<0.001). In conclusion, SAA concentration below the detection limit were considered as good indicators of healthy udder quarters. A substantial variation in SAA concentration in milk and serum was observed in buffalos with bacterial infection. For this reason SAA can be considered as a good marker for early mastitis diagnoses.