Impact of Maternal Protein Restriction on Meat Quality and Fatty Acid Profile of Progeny

Carcass composition and meat quality attributes may be altered by developmental changes that occur in the fetus due to maternal nutrient restriction. The objective of this study was to evaluate the impact of metabolizable protein (MP) restriction in mid- and late-gestation on meat quality and fatty acid profile of progeny. One hundred eight primiparous Angus × Simmental heifers were blocked by BW, conception type (AI or natural service), and calf sex and allocated to 12 pens in a randomized complete block design with a 2 ´ 2 factorial structure including 2 stages of gestation (mid- and late-) and 2 levels of dietary protein (control [CON]; approximately 102% of MP requirements and restricted [R]; approximately 80% of MP requirements). Following weaning, calves were finished in a GrowSafe feeding system on a common diet and individual carcass data was collected. At harvest, 9-10-11 rib sections were removed for carcass composition analysis and strip loins were collected for fabrication of steaks at 3, 7, 14, and 21 days postmortem for tenderness evaluation. Raw steaks were weighed, cooked to 71°C, re-weighed, and cooled before removing cores for Warner-Bratzler shear force (WBSF) analysis. Additional steaks were analyzed to determine fatty acid (FA) percentage (% of total FA content). As previously reported, there were no differences in hot carcass weight, adjusted 12^th rib fat thickness, KPH, marbling score, or USDA quality grades (P > 0.05). The LM area was greater (P = 0.05) for progeny from dams that were restricted during late-gestation vs. CON (92.3 vs. 89.3 ± 1.09 cm²); however, means were similar (P > 0.05) when using HCW as a covariate. A mid- × late-gestation treatment interaction (P = 0.0008) for WBSF showed improved tenderness for progeny from dams on R and CON diets throughout gestation (R-R and CON-CON; mean 2.8 ± 0.08) vs. progeny from dams restricted in mid-gestation only (R-CON; mean 3.2 ± 0.08). Steak cook loss, percent ether, and carcass edible and inedible compositions were not different (P > 0.05) among treatments. Progeny from dams on the R treatment during mid-gestation produced steaks with greater (P = 0.05) percentage of polyunsaturated FA (4.6% ± 0.22) compared with progeny from dams on the CON diet in mid-gestation (4.0% ± 0.22). No differences (P > 0.05) in percent monounsaturated or saturated FA were observed. Differences in tenderness and FA profiles indicate MP restriction during mid- and late-gestation may influence progeny meat characteristics.