116 - The Effects of Dietary Phenylalanine on Gastric Emptying, Macronutrient Metabolism and Feed Intake in Healthy Adult Cats

Abstract: Phenylalanine (Phe) consumption may delay gastric emptying (GE) and feed intake. Two studies were conducted using a 2*2 latin square design with 12 healthy male cats to evaluate effects of 1) dietary Phe (PHE, 44mg/kg-BW) compared with an isonitrogenous amount of alanine (ALA, 23.7 mg/kg-BW) on feed intake, and 2) PHE and ALA on GE and GE rate (GER). In study 1, cats were given PHE or ALA 15 minutes before 120% of their daily food and intake was measured. Treatment, day, and their interaction were evaluated using PROC GLIMMIX in SAS. Treatment did not affect rate of food consumption (p >0.05). For study 2, cats were provided PHE or ALA 15 minutes before receiving 100% of their daily food intake for 3 days. On d4, cats received PHE or ALA and subsequently received [1-¹³C] octanoic acid (5mg/kg BW) on 10g of feed before being fed 50% of their daily food intake. Breath samples were collected to measure ¹³CO₂ enrichment for 12 hours post-meal using indirect calorimetry. Data from cats that returned to baseline enrichment were evaluated for total AUC (GE) and time to peak enrichment (GER). The effect of treatment, body condition score (lean vs. overweight), and their interaction were evaluated using PROC GLIMMIX in SAS. Cats receiving PHE had later peaks (445±71 min) in ¹³CO₂ enrichment (p< 0.05) than cats receiving ALA (244±71 min) but had similar total GE (p >0.10). Obese cats tended (P=0.09) to have greater total GE than lean cats, regardless of treatment. Lean cats on PHE had slower (p< 0.05) emptying rates than lean cats on ALA, but both were similar to obese cats (p >0.05). Overall, Phe did not reduce feed intake or total GE but did delay GE and thus reduced GER. A longer study is warranted to understand whether PHE can control food intake in cats.