Feeding Supplemental Vitamin D3 Improves Pork Longissimus Muscle Quality

Duroc-cross pigs (n = 25) were assigned to one of three experimental finishing diets containing 0 (CON), 40,000 (40), or 80,000 (80) IU supplemental vitamin D3/kg of feed to test the effects of vitamin D3 on pork quality traits. Experimental diets were fed for 44 or 51 days prior to slaughter and days on feed were blocked in the experimental design. While the concentration of vitamin D3 did not affect average daily gain (ADG; P= 0.08), a trend did exist for those receiving the highest concentration of vitamin supplementation to have a lower ADG (0.77 kg/day) compared to pigs fed either the 40 (0.88 kg/day) or CON (0.92 kg/day) diets. Diet did not affect (P > 0.10) fat thickness measured along the midline, 10th rib fat, longissumus (LD) cross-sectional area, or muscle score, but the pigs fed the 80 diet had lower (P > 0.003) hot carcass weights compared to pigs fed either CON or 40 diets. Longissimus pH in the diet main effect was higher (P < 0.05) for pigs on the 80 diet than those on the CON diet. Longissimus muscles from pigs fed either the 40 or 80 diet had lower (P < 0.05) L* values (less white) compared to those fed the CON diet. Trends existed (P > 0.10) for a* values to be higher for muscles taken from pigs fed the 80 diet compared to those fed the CON diet. Objective LD color scores were higher (P < 0.01) and firmness/wetness scores lower (P < 0.05) for pigs on the 80 diet as compared to those on the 40 or CON diets. Diet had no effect on Warner-Bratzler sheer force evaluation, percent cook loss or trained sensory panel evaluation for tenderness, juiciness and flavor. These data indicate that feeding supranutritional levels of vitamin D3 for at least 44 days improves pork color and pH, but may retard growth if fed at 80,000 IU/kg of feed.