Comparison of red meat versus high carbohydrate diet using the gilt biomedical model: Body composition

Abstract Text: The objective of this study was to determine differences in body composition, blood chemistry, and insulin receptor density of adipocyte and muscle fibers associated with a high calorie, high glycemic diet.  Yorkshire x Duroc x Hampshire gilts (N = 21) born over a five-day period from a common sire were fed ad libitum a low lysine diet (Lys < 0.45%) to promote hyperphagia and adiposity. Upon reaching 3 cm subcutaneous backfat (10BF; 10/11th rib interface), dietary treatments were allocated across BW and BF to either a ground beef (GB; n = 5) or control (CON; n = 5) treatment. The GB diet was 99.9% cooked ground beef (65:35 lean:fat) plus 0.1% calcium carbonate while CON comprised 83% ground corn, 10% distillers dried grains plus solubles, and 5% soybean meal. Both rations met NRC requirements for gilts of this size and weight. Intake and orts were recorded daily. Body weights (BW) and blood draws were collected on d0, 28, 56, and 84. Gilts were humanely euthanized on d85 for tissue collections and body composition analysis. One gilt was removed from the GB due to foot infection.  The CON gilts gained 0.77 while GB gilts gained 0.61. kg/d (P = 0.02). Estimated kilocalorie consumption/d was less (P = 0.01) for CON (14,322 kcals/d) versus GB (17,896 kcals/d) from d 35 to 84. The percentage change of 10BF and BW from d0 were calculated as [(d28, 56 or 84 – d0)/d0] and evaluated as repeated measure for the interaction of treatment by day.  The GB gilts had a greater percent change in BW (P = 0.002) and 10BF (P < 0.02). Control gilts had more (P = 0.04) perirenal fat than GB (5.05 vs. 5.50 Kg, respectively). No differences were observed (P ≥ 0.25) for adrenal, liver, or spleen weights, however the hearts of the CON gilts tended (P = 0.08) to be heavier compared to the GB gilts.  Gilts in the GB treatment consumed 1.25 times more caloric energy than CON and gained less body fat.

Keywords: Gilts, body composition, biomedical