Postmortem Aqueous Humor Analysis in Pigs as an Index of Antemortem Serum Biochemistry Profile and Diagnostic Aid in Animal Welfare

The present study aimed to assess whether postmortem analysis of aqueous humor in pigs can be used to estimate antemortem serum biochemical values. The experimental design used a control group to establish regression equations linking postmortem aqueous humor to antemortem serum biochemical values. These models enabled reconstruction of the physiological status in decomposed forensic cases associated with heatstroke and hypoxia in pigs that died following a ventilation system failure on a commercial farm, and assessment of physiological distress, cause of death, and potential intentional animal abuse. Concentrations of albumin (ALB), alkaline phosphatase (ALP), alanine aminotransferase (ALT), amylase (AMY), total bilirubin (TBIL), urea nitrogen (UN), creatinine (CRE), calcium (Ca), phosphate (PHOS), sodium (Na), potassium (K), glucose (GLU) and total protein (TP) were measured in aqueous humor and compared with serum samples obtained after slaughter of 30 pigs. Biochemical analyses were performed using a chemistry analyzer with commercial reagent rotors designed. Strong correlations were observed for Na, K and CRE concentrations and for ALT and UN activities between aqueous humor and serum, while TP, ALB, AMY, TBIL and Ca showed weaker associations. Notably, CRE and UN showed strong postmortem correlations with serum values in pigs, consistent with findings in cats and other species, highlighting their reliability as indicators of renal function. Electrolyte concentrations, particularly K and Na, followed consistent and well-recognized patterns described in both human and veterinary forensic studies, with K levels in pigs comparable to those observed in other domestic animals. The results indicate that postmortem aqueous humor analysis of CRE, Na, K, AST, and UN provides a reliable estimation of corresponding serum values in pigs, representing a useful diagnostic and forensic tool in the case of animal welfare.