Comparison of red meat versus high carbohydrate diet using the gilt biomedical model: liver and muscle energy use

Abstract Text: Twenty-one Yorkshire x Duroc x Hampshire gilts born over a five-day period and sired by a common boar were selected for use at approximately 90 d of age. Prior to being allotted to diets, gilts were housed in individual pens (1.22 x 2.44 m) in a thermo-neutral and environmentally controlled room. Gilts were fed a common lysine-deficient diet (Lys < 0.45%) once daily to promote hyperphagia and adiposity until they reached 3 cm subcutaneous backfat (BF; 10/11th rib interface). When the first gilts reached 3 cm of subcutaneous backfat by ultrasound they are allocated to either a ground beef (GB; n = 5) or control (CON; n = 5) diets. The GB 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. Gilts were humanely slaughtered on d 85 and tissues were collected. The liver was weighed and samples of liver and sternomandiubularis muscle were immediately collected for in vitro O₂ consumption analyses. Duplicate tissue samples (200 mg) were placed into test chambers containing 3 ml of buffer and a Clarke polariographic electrode and  O₂ consumption measured for 5 min. Liver mass (g and g/kg BW) did not differ (P = 0.52 and P = 0.27) between treatments. Oxygen consumption (µmol/min/g) in liver was greater (P = 0.04) in gilts fed the GB diet compared to CON. However, O₂ consumption (µmol/min/g) in muscle did not differ (P = 0.28) between the treatments. Feeding ground beef increased O₂ consumption of liver tissue, potentially because of the increased workload associated with the metabolism of excess dietary protein.

Keywords: Ground beef, liver, O₂ consumption