Monitoring of biochemical profile and Serum Amyloid A in lactating jennies

In the last years, the assessment of specific acute phase proteins has been added to routine blood work (such as hematological and biochemical analysis) to support clinicians in the early recognition and differentiation of acute infection and inflammation from other more benign clinical disease. In horses, serum amyloid A (SAA) is an acute phase protein of the family apolipoproteins, mainly produced by the liver, that rapidly increases in response to inflammation [1]. Despite the increasing interest in donkeys reared for milk production and the high potential of SAA for the early diagnosis of inflammatory diseases in equids, no study investigated SAA concentrations in dairy donkeys. For the present study, 20 clinically healthy Ragusana jennies were divided into two groups: group A included jennies that foaled within 48 hours while group B included jennies at 30 days of lactation. On blood samples, a biochemical profile was performed including Potassium (K), Sodium (Na), Chloride (Cl), Calcium (Ca), Phosphorus (P), Calcium/Phosphorus ratio (Ca:P) blood urea nitrogen (BUN), γ-glutamiltrasferasi (GGT), glucose (Glu), creatinine (Cre), glutamic oxaloacetic transaminase (GOT), serum glutamic pyruvic transaminase (GPT), lactate dehydrogenase (LDH), Alkaline phosphatase (ALP), cholesterol (Chol), triglyceride (Trig), creatine kinase ( CK), total bilirubin (tBil), direct bilirubin (dBil), indirect bilirubin (iBil), total protein (TP), albumin (Alb), globulins (G) Albumin/Globulin ratio (Alb:G). SAA levels have also been assessed by a solid phase sandwich enzyme-linked immunosorbent assay (ELISA). Student’s T-test was performed to evaluate significant differences in biochemical profile and SAA between Group A and B. All jennies delivered at term (mean gestation length 355±19 days), by spontaneous eutocic parturition, healthy viable foals. Statistical analysis revealed significant higher values of SAA (p<0.001), Chol (p=0.035), tBil (p=0.001), dBil (p=0.002) and iBil (p=0.001), and lower Alp (p=0.011) in group A compared with group B. The modifications of biochemical profile observed in jennies during the early post-partum are similar to changes observed in periparturient mares [2,3]. The evidence of higher SAA in jennies after foaling expressed the stress associated with delivery, event that might lead to disturbances in the systemic homeostasis of mare and the occurrence of perinatal disorders [3]. Several studies confirm that regular assessment of serum SAA level carried out within the broadly understood prophylaxis can be a sensitive index of disturbances in the internal homeostasis of the body, especially in the absence of clinical symptoms. This is of particular importance in dairy jennies as the early recognition of pathological conditions during the first post-partum and the early lactation period can have direct effects both on milk production and on donkey foal survival. Based on obtained results, future studies about possible correlation between CBC and SAA during peripartum in jennies could be of interest. [1] Long A, Nolen-Walston R. Equine Inflammatory Markers in the Twenty-First Century: A Focus on Serum Amyloid A, Vet Clin Equine 36:147–160, 2020. [2] Bazzano et al. Metabolic Profile of Broodmares During Late Pregnancy and Early Post-Partum, Reprod Dom Anim, doi: 10.1111/rda.12411, 2014. [3] Krakovski et al. The Level of Prolactin, Serum Amyloid A, and Selected Biochemical Markers in Mares Before and After Parturition and Foal Heat, J Equine Vet Sci, 84:102854, 2020.