Fish oil-supplemented parenteral diets normalize splanchnic blood flow andimprove killing of translocated bacteria in a low-dose endotoxin rat model

Objective: Intestinal ischemia decreases barrier function of the gut and en hances translocation of bacteria and toxins, Several studies indicate that fish oil can modulate prostaglandin formation and thus, regional blood how and immune function. This study was performed to determine the effects of p arenteral diets with omega-3 fatty acids on microcirculation and barrier fu nction of the gut. Design: Prospective, randomized, controlled animal study. Setting: University laboratory. Subjects: A total of 64 male Sprague-Dawley CD rats. Interventions and Measurements: For 48 hrs, eight groups of eight rats each received total parenteral nutrition with four different types of lipids. T he source of fat in group L was soybean oil only and in group L-M a mixture of soybean oil and medium-chain triglycerides. In groups FO-20 and FO-40, 20% or 40%, respectively, of the soybean oil in group L-M was replaced by f ish oil. The other four groups received an additional continuous infusion o f endotoxin (0.1 mg/100 g body weight per day) for the last 24 hrs. Blood f low was measured with microspheres, and translocation was determined by mic robiological methods and instillation of radioactive-marked bacteria into t he gut. Main Results: In the animals without fish oil, the endotoxin application re duced the blood flow to the intestine similar to 25%. Animals with fish oil in their diets showed normal values. Translocation of gut bacteria was inc reased significantly in all endotoxin groups. However, less-viable bacteria could be detected in the animals with fish oil diets in their mesenteric l ymph nodes and livers. Conclusions: In this model, diets enriched with fish oil abolish the endoto xin-induced decrease of nutritive blood flow to the gut and ameliorate the bactericidal defense of the splanchnic region. The lower count of viable ba cteria in the fish oil groups is more related to an improved killing of tra nslocated bacteria than a reduction of the translocation rate.