Dietary supplementation of magnesium sulfate and sodium bicarbonate and its effect on pork quality during environmental stress

Market hogs (n = 160) were allotted to four dietary treatments to evaluate the effectiveness of magnesium sulfate (MgSO4) and sodium bicarbonate (NaHCO3) on improving pork quality during times of environmental stress. The experiment was conducted in four different months (Trial) to evaluate temperature as an environmental stressor. The dietary treatments were: 1) control 2) control + 3.2 g⁎pig-1⁎d-1 of MgSO4 for a minimum of 14 days prior to slaughter, 3) control + 1.5% NaHCO3 fed for 48 h prior to slaughter, and 4) control + 3.2 g⁎pig-1⁎d-1 MgSO4 + 1.5% NaHCO3. No differences (P > 0.05) in pork quality were found between dietary treatments. Live weight, carcass weight and dressing percentage did not differ (P > 0.05) by Trial whereas measures of pork quality (24 h pH, L, a, and b values, NPPC color scores, drip loss, and Warner Bratzler shear force [WBSF]) values were affected (P < 0.05) by Trial. Time in lairage increased (P < 0.05) dressing percentage and impacted (P < 0.05) initial loin pH, 24 h ham pH, ham a values, and WBSF. Although dietary treatment had no effect on pork quality, the month of the year when pigs were slaughtered played a relevant role in pork quality.