Date Full Report Received06/09/2015
Date Abstract Report Received06/09/2015
Funded ByNational Pork Board
The effect of diet on physiological and chemical balance was assessed when mature, obese gilts were fed either a high fat ground beef (GB) or a high carbohydrate corn/soybean diet (CON). A pool of 21 crossbred gilts was provided ad libitum access to a low lysine diet to promote over-eating and adiposity. The first 10 gilts to reach 3 cm of back fat (BF) were randomly assigned to either the GB or CON diet. Five gilts were assigned to the GB diet, which consisted of fully cooked 65:35 lean:fat ground beef top dressed with calcium carbonate (0.1%). Five gilts were also assigned to the CON diet which was made up of 70.6% ground corn, 15% vegetable oil, 8.5% dried distillers grains with solubles (DDGS) and 4.25% soybean meal. Body weight and blood draws were done on day 0, 28, 56 and 84. Back fat thickness and loin muscle area were determined via ultrasound every 28 days. Blood analysis and blood lipid panel was conducted. Gilts were humanely euthanized on day 85 for tissue collections and body composition analysis. There were no significant differences between treatments seen when using qPCR analysis for expression of IR in the longissimus, gracilis, 10th rib backfat, or liver (P = 0.43, 0.2, 0.13, and 0.19, respectively). Tagged (immunofluorescence) insulin receptor (IR) density was not different across treatment for muscle of posture (longissimus thoracis) or subcutaneous fat collected adjacent the first thoracic vertebra. However, fluoresced IR density of GB gracilis muscle was superior to CON (P = 0.04) suggesting greater insulin sensitivity for this muscle of locomotion. More research is necessary involving the physiological response to food or combinations of food to determine if the obesity trend can be attributed to the increase in carbohydrate consumption and if red meat can play a role in reversing tissue-specific down-regulation of insulin receptors.