**Background:** The coefficient of fat absorption (CFA) has been the standard test for diagnosing exocrine pancreatic insufficiency (EPI) and evaluating pancreatic enzyme replacement therapy (PERT), but it quantifies fat remaining in stool rather than directly measuring lipolysis. CFA does not correlate with PERT dose, limiting its utility for dose-ranging studies. Long-chain polyunsaturated fatty acids (LCPUFAs) like docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) must be hydrolyzed by pancreatic lipase before absorption, and their plasma levels following ingestion could serve as a direct indicator of lipase activity and global fat absorption.
**Methods:** The study used an established EPI pig model (n=12 pigs, ~13.5 kg). Pigs were fed a high-fat diet (20% fat) and given a standardized omega-3 substrate challenge (six 2,000 mg softgels providing 3000 mg EPA and 1500 mg DHA). Blood samples were drawn at 0, 1, 2, 4, 6, 8, 12, and 24 hours. SNSP003 (a novel microbially-derived lipase) was tested at doses of 20 mg, 40 mg, 80 mg, and 120 mg lipase. Porcine pancrelipase (Kreon 25,000) was given at 50,000 lipase units per meal (~3,750 lipase units/kg/meal). Fatty acid analysis was performed using gas chromatography. Statistical analysis used Brown-Forsythe and Welch ANOVA for normally distributed data or Kruskall-Wallis test with uncorrected Dunn's test for non-normally distributed data.
**Key Results:** The absorption of omega-3 fats (DHA+EPA) was significantly increased following administration of 40, 80, and 120 mg SNSP003 lipase by 51% (p=0.02), 89% (p=0.001), and 64% (p=0.01), respectively, compared to no lipase, with Tmax at 4 hours. AUC24 for DHA+EPA increased by 83% (p=0.001) for 80 mg and 62% (p=0.01) for 120 mg. Cmax increased by 60% (p=0.009) for 80 mg, 45% (p=0.05) for 120 mg, and 40% (p=0.07) for 40 mg. When comparing the two highest SNSP003 doses to porcine pancrelipase, no significant differences were observed. Plasma DHA+EPA AUC24 increased by 126% (p=0.007) for 80 mg, 141% (p=0.09) for 120 mg, and 122% (p=0.027) for pancrelipase. For total long-chain fatty acids (C14:C24), AUC8 increased by 141% (p=0.001) for 80 mg and 133% (p=0.006) for 120 mg compared to no lipase. Cmax for total fatty acids increased by 128% (p=0.003) for 80 mg and 157% (p=0.013) for 120 mg. No significant differences were observed between SNSP003 doses and pancrelipase for total fatty acid absorption.
**Clinical Implications:** The omega-3 SACT successfully differentiated among different lipase doses in EPI pigs, demonstrating dose-response capability that CFA lacks. The test correlates with global fat lipolysis and absorption, as absorption of DHA and EPA reflected absorption of the full range of dietary fats. The pharmacokinetic-like profile (Tmax at 4 hours for omega-3s, 2 hours for total fats) provides detailed information about lipase activity timing. The authors suggest the omega-3 SACT could be paired with RBC omega-3 index for long-term assessment, analogous to blood glucose and hemoglobin A1c in diabetes. Limitations include small sample size (though effect size was large), use of EPI pig model rather than humans, and use of some ethyl ester omega-3s (not metabolized by pancreatic lipase). The authors recommend future studies in humans using pure DHA triglyceride as the substrate.