Supplementation of glycerol or fructose via drinking water to enhance marbling deposition and meat quality of finishing cattle.

Thirty-six Angus-cross steers (667 ± 34.4 kg initial BW, 24.5 mo) were used to assess the impact of short-term glycerin or high-fructose corn syrup administration via drinking water on meat quality and marbling deposition. Steers blocked by BW (3 blocks) were assigned randomly to 1 of 3 drinking water treatments: 1) control (CON), 2) 4.3% crude glycerin (GLYC), or 3) 4.3% high-fructose corn syrup (HFCS) for the final 25 d before slaughter. Average daily gain was lower ( = 0.01) and final live weight was lower ( < 0.01) with HFCS administration compared with CON. Dry matter intake and water intake did not differ among treatments. Fat thickness, muscle depth, and intramuscular fat measured by ultrasound did not differ among treatments. Crude glycerin or HFCS via water supplementation did not alter HCW, dressing percentage, rib eye area, fat thickness, KPH, skeletal maturity, or marbling score. Longissimus muscle and subcutaneous fat color (L*, a*, and b*) were not affected by drinking water treatment. Total lipid content, total fatty acid content, and fatty acid composition of the LM did not differ among drinking water treatments. Supplementation of drinking water with GLYC or HFCS did not alter Warner-Bratzler shear force values or water-holding capacity (drip loss, cook shrink). Intramuscular mean adipocyte diameter was greater ( = 0.02) for steers offered HFCS compared with steers offered GLYC, with CON steers being intermediate. These differences in mean adipocyte size were related to changes in the adipocyte size distribution. There were greater proportions of small (20 to 30 μm) adipocytes in GLYC compared with HFCS and CON. In contrast, HFCS and CON had greater proportions of medium (40 to 50 μm) adipocytes than GLYC. The relative mRNA expression of lipogenic genes (acetyl Co-A carboxylase [ACC], fatty acid binding protein 4 [FABP4], fatty acid synthase [FASN], glycerol-3-phosphate acyltransferase [GPAT], retinol-binding protein 4 [RBP4], and stearoyl-CoA desaturase [SCD]), adipocyte differentiation genes (delta-like 1 homolog [DLK1]), and transcription factors (CCAAT/enhancer-binding protein α [C/EBPα], and PPARγ) was similar for GLYC and HFCS compared with CON. Longissimus glycogen and lactate concentrations and glycolytic potential were not affected by drinking water treatments. Overall, HFCS or GLYC supplementation via drinking water did not alter carcass or meat quality variables but did alter the size and distribution of intramuscular adipocytes. These results indicate that a longer supplementation time or a higher substrate level may be needed to obtain differences in meat quality.