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Conjugated linoleic acid (CLA) was supplemented to crossbred growing-finishing barrows (n = 60) at 0.75% of the total diet. Pigs were randomly assigned to the CLA or control diets based on stress genotype (negative, carrier, or positive). Gain:feed was higher for CLA diet animals (350 g/kg feed) than for control diet animals (330 g/kg feed) independent of genotype (P [is less than] 0.05). No differences were observed for ADG for the diets (P = 0.71) or genotype classes (P = 0.40). Postmortem pH was lower (P [is less than] 0.01) by 3 h for CLA-supplemented pigs, with no differences in ultimate pH. No differences (P = 0.16) were observed for ultimate pH between the three genotypes. Conjugated linoleic acid-supplemented pigs exhibited less 10th rib fat depth (2.34 cm vs 2.84 cm) and last rib fat depth (2.46 cm vs 2.72 cm) than control pigs (P [is less than] 0.05). Loin muscle area (LMA) was not affected (P = 0.18) by CLA supplementation, but LMA was different (P [is less than] 0.02) for genotype; positive genotype carcasses had the largest LMA (45.02 [cm.sup.2]) and negative carcasses had the smallest LMA (36.44 [cm.sup.2]). Carrier carcasses were intermediate for LMA (40.76 [cm.sup.2]). Subjective scores for color were not affected (P = 0.98) by CLA but color was different (P [is less than] 0.01), with scores of 1.50, 2.40, and 3.1 for positive, carrier, and negative genotypes, respectively. Subjective marbling scores were increased (P [is less than] 0.03) in all genotypes with CLA supplementation. Subjective firmness scores were higher (P [is less than] 0.06) for CLA-supplemented pigs and were highly correlated (0.89) to marbling scores. The L(*) values were higher (P [is less than] 0.01) for stress-positive pigs at 24 h postmortem. Also, L* values were higher (P [is less than] 0.01) for CLA-fed pigs over 7 d of shelf storage. Sensory characteristics were not different with CLA supplementation for tenderness (P = 0.24), juiciness (P = 0.35), or flavor intensity (P = 0.14). This study showed that LMA was increased with stress-carrier and stress-positive genotypes, but lean color was negatively affected with the presence of the stress gene. Conjugated linoleic acid supplementation improves feed efficiency, decreases backfat, and improves pork quality attributes of marbling and firmness of the longissimus muscle. Furthermore, there is seemingly no interaction between the stress-genotype status of pigs and the subsequent effect of CLA on their growth and performance. Key Words: Linoleic Acid, Meat Quality, Pigs

The objective of this study was to determine whether feeding high doses of vitamin [D.sub.3] 7 d before slaughter would increase muscle [Ca.sup.++] levels and result in more tender loin chops. Market lambs (n = 4 callipyge and 4 normal in Exp. 1, and n = 16 calipyge and 16 normal in Exp. 2) were randomly and equally assigned to feeding groups based on callipyge genotype and experimental diet, (vitamin [D.sub.3] or control). Serum [Ca.sup.++], muscle [Ca.sup.++], Warner-Bratzler shear force, and troponin-T degradation data were analyzed. In Exp. 1, vitamin [D.sub.3] was supplemented at 1 or 2 x [10.sup.6] IU/d. The 2 [10.sup.6] IU dose resulted in the greatest serum [Ca.sup.++] reponse and was chosen for Exp. 2. In Exp. 2, serum [Ca.sup.++] concentration was higher (P [is less than] 0.05) for normal and callipyge lambs fed the vitamin [D.sub.3] diet than for the control diet fed lambs. Muscle [Ca.sup.++] concentrations, however, were not higher (P = 0.28) for the vitamin [D.sub.3]-fed lambs. Warner-Bratzler shear values were higher (P [is less than] 0.05) for callipyge than for normal lambs, but no differences were observed with vitamin [D.sub.3] supplementation. These data were supported by results from Western blot analysis of troponin-T degradation, in which no differences were observed for vitamin [D.sub.3] vs control diet lambs at 14 d postmortem. This experiment showed that feeding 2 x [10.sup.6] IU/d of vitamin [D.sub.3] to market lambs, callipyge or normal, raised serum [Ca.sup.++] concentration, but did not increase muscle [Ca.sup.++] concentration. This lack of response in muscle [Ca.sup.++] was likely the reason that no differences were observed for Warner-Bratzler shear force values or troponin-T degradation data between the vitamin [D.sub.3] and control loin chops. A higher dose of vitamin [D.sub.3] may be required to improve tenderness. Key Words: Sheep Breeds, Tenderness, Vitamin [D.sub.3]

Conjugated linoleic acid (CLA) is a collective term for positional and geometric isomers of linoleic acid. Dietary CLA has been shown to improve feed efficiency, decrease body fat, and increase lean tissue in laboratory animals. We hypothesized that CLA would improve performance and carcass composition and would be deposited in pork tissues. Diets of 40 crossbred pigs were supplemented with CLA to determine its effects on performance and carcass composition. Eight replications of five littermate barrows with an initial average weight of 26.3 kg were allotted at random to individual pens. Within replication dietary treatments containing 0, 0.12, 0.25, 0.5, or 1.0% CLA were assigned at random. Pigs were weighed and feed disappearance was determined at 14-d intervals. Average daily gain increased linearly as the level of CLA increased in the diet (P [is less than] 0.05). Average daily feed intake was not affected by the concentration of CLA in the diet. Therefore, a linear increase in gain:feed ratio (P [is less than] 0.05) was observed. Carcasses from animals fed control diets had greater 10th rib backfat than carcasses from animals fed CLA (P [is less than] 0.05). Ultrasound measurement and carcass measurements showed less fat depth over the loin eye at the 10th rib of pigs fed doses of CLA (P [is less than] 0.05) than that observed for control pigs. Belly hardness (firmness) increased linearly as the concentration of CLA in the diet increased when bellies were measured for firmness either lean side up (P [is less than] 0.001) or lean side down (P [is less than] 0.05). Loin dissection data demonstrated that CLA produced a quadratic treatment effect both for less intermuscular fat (P [is less than] 0.001) and less subcutaneous fat (P [is less than] 0.05) and a linear increase for bone (P [is less than] 0.05), although finished loin weight only tended to increase (P = 0.08). The CLA concentration increased in a linear relationship in both subcutaneous fat (P [is less than] 0.001) and lean tissue (P [is less than] 0.001). Dietary CLA was incorporated into pig tissues and had positive effects on performance and body composition. Key Words: Body Composition, Linoleic Acid, Pork

This study was designed to observe the effects of conjugated linoleic acid (CLA) supplementation on lean content of pork carcass primal cuts (hams, loins, and bellies) and to determine the ability of total body electrical conductivity (TOBEC) to predict lean content. A total of 64 crossbred growing-finishing barrows were placed on a control (soybean oil) or CLA (0.75%) diet at an average weight of 40 kg. Pigs were penned in pairs according to diet and stress genotype (negative, carrier, and positive) and slaughtered at 115 kg. Stress genotype was included because of known variations in lean content. Hams (IMPS 401A; n = 64), loins (IMPS 410; n = 24), and bellies (IMPS 408; n = 63) were fabricated from carcasses at 24 h postmortem and scanned 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 were skinned prior to scanning then subjected to a belly bar firmness test before dissection. Supplementation with CLA had no effect (P [is greater than] 0.05) on lean ham composition. Regression analysis was used for lean weight prediction using primal weight and PMA value as predictors. Lean content prediction of hams by TOBEC resulted in an [R.sup.2] of 0.80. Loins from CLA-supplemented pigs exhibited increased lean weight (P [is less than] 0.05) and PMA values (P [is less than] 0.05) compared to controls. Lean prediction of loins by TOBEC resulted in an [R.sup.2] of 0.66. Bellies from CLA-supplemented pigs had a higher percentage of moisture (P [is less than] 0.03) and protein (P [is less than] 0.01) and decreased percentage of lipid (P [is less than] 0.01). The [R.sup.2] values from the regression analysis predicting protein, moisture, protein + moisture, and fat-free soft tissue composition of the skinless bellies were 0.67, 0.68, 0.71, and 0.78, respectively. Key Words: Electrometric Methods, Linoleic Acid, Pork, Unsaturated Fatty Acids