Ensure plus liquid diet

Male Long-Evans rats (n=71) (250–300 g; Harlan Laboratories, Indianapolis, Indiana, USA) were individually housed and maintained on a 12/12 hour light/dark cycle (lights off at 18:00 hours) at 25°C and 50%–60% humidity. All procedures for animal use were approved by the University of Cincinnati Institutional Animal Care and Use Committee. Before surgery, rats were given ad libitum access to water and a high-fat diet (4.54 kcal/g; 41% fat; Research Diets, New Brunswick, New Jersey, USA) previously documented to produce metabolic impairments.12 (link) After 8 weeks on the high-fat diet, rats were assigned to one of five surgical groups (sham, JIB, 30 cm PJD, 42 cm PJD or RYGB) that were matched for fat tissue mass. At 3 days pre-operatively, the high-fat diet was temporarily replaced with Ensure Plus liquid diet (1.41 kcal/g; 29% fat) (Abbott Nutrition, Columbus, Ohio, USA) for 7 days after which the rats were returned to the same high-fat diet as before. Subcutaneous injections of Metacam (0.25 mg/100 g body weight (BW) once daily for 4 days), gentamicin (0.8 mg/100 g BW on the day of surgery), Buprenex (0.3 mL 2X per day for 5 days), and warm saline (10 and 5 mL 2X per day for days 0–3 and 4–5, respectively) were given to all post-operative rats. On the day of surgery, rats were anesthetized under isoflurane and pre-treated with analgesics and gentamicin as above.

The HFD was replaced with Ensure Plus liquid diet (1.41 kcal/g, 29% fat; Abbott Nutrition, Columbus, OH) 24 h prior to surgery. A liquid diet was continued for 120 h and then replaced with an HFD. Subcutaneous injections of Metacam (0.25 mg/100 g BW once daily for 4 days), gentamicin (0.8 mg/100 g BW on the day of surgery), Buprenex (0.3 mL 2 times per day for 5 days), and warm saline (10 and 5 mL 2 times per day for days 0–3 and 4–5, respectively) were given to all postoperative rats.