Effect of level, source, and time of feeding prior to slaughter of supplementary dietary magnesium on pork quality

A total of 192 pigs were utilized in a 2×3×3 factorial arrangement with an additional control treatment. The treatments were: (1) magnesium level (1.6 vs. 3.2 g of magnesium pig^-1 day^-1); (2) magnesium source (sulfate vs. proprionate vs. proteinate); (3) feeding duration (5 vs. 2 vs. 1 day), and a control (no supplementary magnesium). Minolta L* values were lower (P≤0.05), indicating darker muscle color, for pigs supplemented with 1.6 g magnesium pig^-1 day^-1 compared to the controls while pigs on the 3.2 g magnesium level were intermediate between these two treatments. Animals on the 1 day treatment had a higher (P≤0.05) ultimate pH and lower (P≤0.05) Minolta L* compared to those on the 2 days and control treatments, while 5 days pigs were intermediate and had lower L* values compared to the controls. The sulfate and proteinate treatments produced pork with the lower (P≤0.05) Minolta L* values compared to the controls. Pigs fed the sulfate diet had a lower (P≤0.05) drip loss compared to those on the control treatment. Results from this study suggest that the lowest level (1.6 g magnesium pig^-1 day^-1) and the shortest time of supplementation (1 day) may be effective in improving pork color and water-holding capacity.