Total body electrical conductivity (TOBEC) measurement of compositional differences in hams, loins, and bellies from conjugated linoleic acid (CLA)-fed stress-genotype pigs

This study was designed to observe the effects of conjugated linoleic acid (CLA) supplementation on lean content of pork carcass primal cuts (hams, lo ins, and bellies) and to determine the ability of total body electrical con ductivity (TOBEC) to predict lean content. A total of 64 crossbred growing- finishing barrows were placed on a control (soybean oil) or CLA (0.75%) die t at an average weight of 40 kg. Pigs were penned in pairs according to die t and stress genotype (negative, carrier, and positive) and slaughtered at 115 kg. Stress genotype was included because of known variations in lean co ntent. Hams (IMPS 401A; n = 64), loins (IMPS 410; n = 24), and bellies (IMP S 408; n = 63) were fabricated from carcasses at 24 h postmortem and scanne d for electromagnetic (EM) absorption by a MQ-25 EM scanner. Each wholesale cut was scanned in triplicate at 2.5 MHz to yield a peak mean average (PMA ) value then separated into lean, fat, bone, and skin components. Bellies w ere skinned prior to scanning then subjected to a belly bar firmness test b efore dissection Supplementation with CLA had no effect (P > 0.05) on lean ham composition. Regression analysis was used for lean weight prediction us ing primal weight and PMA value as predictors. Lean content Prediction of h ams by TOBEC resulted in an R-2 Of 0.80. Loins from CLA-supplemented pigs e xhibited increased lean weight (P < 0.05) and PMA values (P < 0.05) compare d to controls. Lean prediction of loins by TOBEC resulted in an R-2 of 0.66 . Bellies from CLA-supplemented pigs had a higher percentage of moisture (P < 0.03) arid protein (P < 0.01) and decreased percentage of lipid (P < 0.0 1). The R-2 values from the regression analysis predicting protein, moistur e, protein + moisture, and fat-free soft tissue composition of the skinless bellies were 0.67, 0.68, 0.71, and 0.78, respectively.