Comparison of red meat versus high carbohydrate diet using the gilt biomedical model: Blood chemistry

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 are 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 slaughtered on d85 for tissue collections and body composition analysis. One gilt was removed from the GB due to foot infection. Blood analysis was conducted using an iSTAT point of care device (Abaxis, Inc.) which measured sodium, potassium, ion calcium, glucose, hematocrit, hemoglobin, pH, PCO₂, PO₂, TCO₂, HCO₃, base excess, and SO₂. Blood lipid panel was assayed for total cholesterol (CHOL), LDL, HDL, and Triglycerides. The GB gilts had a higher 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). The GB gilts had higher circulating LDL (P=0.015), CHOL (P=0.02), and glucose (P=0.04) and lower HCO₃ (P=0.023) and TCO₂ (P=0.018) than CON. Gilts from GB tended to have a higher LDL:CHO ratio (P=0.052) and HDL:LDL ratio (P=0.079), and lower sodium (P=0.107), PCO₂ (P=0.078), and base excess (P=0.087) than CON. Top, middle, and bottom heart ventricular thickness recorded on the right and left sides did not differ (P>0.10) across treatments. The lower adiposity of GB versus CON gilts over 84d did not result in blood lipid panel improvements as GB gilts recorded a higher circulating cholesterol concentration, however these levels were very low (GB=116.09 mg/dL vs. CON=91.04 mg/dL) relative to human biomedical standards.

Keywords: Gilts, Biomedical, Cholesterol