Closed-chamber transepidermal water loss measurement: microclimate, calibration and performance.

The importance of transepidermal water loss (TEWL) as a measure of the skin barrier is well recognized. Currently, the open-chamber method is dominant, but it is increasingly challenged by newer closed-chamber technologies. Whilst there is familiarity with open-chamber characteristics, there is uncertainty about the capabilities of the challengers. The main issues are related to how microclimate affects TEWL measurements. The aim of this paper is to provide a framework for understanding the effects of microclimate on TEWL measurement. Part of the problem is that TEWL measurement is indirect. TEWL is the diffusion of condensed water through the stratum corneum (SC), whereas TEWL methods measure water vapour flux in the air above the SC. This vapour flux depends on (i) the rate of supply of water to the skin surface and (ii) the rate of evaporation of water from the skin surface. Rate (i) is a skin property (TEWL), rate (ii) is a microclimate property. The controlling rate for the combined process is the lower of the above two rates. Therefore, TEWL instruments measure TEWL only when TEWL is the rate-limiting process. Another problem is that SC barrier property and SC hydration are affected by the microclimate adjacent to the skin surface. This is discussed insofar as it affects the measurement of TEWL. The conclusion is that such changes occur on a timescale that is long compared with TEWL measurement times. An important aspect of TEWL measurement is calibration. We present an analysis of the traditional wet-cup method and a new droplet method that is traceable and has been independently verified by a standards laboratory. Finally, we review performance indicators of commercial closed-chamber instruments with reference to open-chamber instruments. The main findings are that TEWL readings correlate well, but there are significant differences in the other aspects of performance.

Characterizing beef muscles with optical scattering and absorption coefficients in VIS-NIR region.

We developed a fiber optical probe to measure spatially resolved diffuse reflectance from beef samples in VIS-NIR bandwidth of 450-950nm. The optical scattering and absorption coefficients were obtained by fitting the measurements with diffuse equation. Beef absorption coefficients are related to the sample chemical compositions such as the concentration of myoglobin and its derivatives; while scattering coefficients depend on meat structural properties such as sarcomere length and collagen concentration. Structural properties are also key factors in determining beef tenderness, therefore we hypothesize that a correlation exists between optical scattering and cooked Warner-Bratzler shear (WBS) force. Thirty-two, unfrozen beef muscle samples obtained from different animals were used in the correlation study. We found a higher scattering coefficient was associated with a higher cooked WBS. A linear regression analysis showed that sample scattering coefficients were significantly (p<0.0001) correlated to the corresponding WBS with a coefficient of determination (R(2)) of 0.59.

The influence of creatine and a high glycemic carbohydrate on the growth performance and meat quality of market hogs fed ractopamine hydrochloride.

Crossbred barrows (n=128; 85±0.91kg) were randomly allotted to one of four dietary treatments. A pelleted corn-soybean diet containing 5ppm Paylean(®) (PAY) was tested against a negative control (NCON) diet formulated to meet or exceed the National Research Council's requirements for the growing pig, a pelleted corn-soybean diet containing 0.92% creatine and 2.75% dextrose (COMBO), and a pelleted corn-soybean diet containing a combination of 5ppm Paylean(®), 0.92% creatine, and 2.75% dextrose (PAYPLUS). No treatment differences were noted when comparing ADG (P=0.66) and hot carcass weight (P=0.75). Over the 27d test, barrows fed PAY and PAYPLUS produced loins with a larger (P<0.01) loin muscle area (LMA) than those fed NCON or COMBO diets. Barrows fed the NCON diet were fatter at the 10th-rib (P<0.01) than those animals fed the remaining dietary treatments. Dietary treatment did not affect the ultimate pH (P=0.87), Japanese color score (P=0.25) or Minolta L(∗) (P=0.61) and b(∗) (P=0.56) values of the loin. Loin chops from NCON, COMBO and PAYPLUS tended (P=0.07) to contain a higher intramuscular fat content than those from barrows fed PAY. Additionally, loin chops from the NCON and COMBO fed animals were more red (higher a(∗)-value) than those chops coming from animals fed the PAY diet (P<0.01).

Effects of post-mortem aging time and type of aging on palatability of low marbled beef loins.

The study objective was to evaluate the effect of post-mortem aging period (14 to 49days), dry vs. wet (D vs W) type of aging on the palatability of bone-in (BI) beef short loins (n=96) and boneless (BL) strip loins (n=96) possessing United States Department of Agriculture marbling scores between Slight and Small. Warner-Bratzler shear force (WBSF) scores decreased linearly over time (P=0.0001). WBSF was not influenced by aging method or loin type. Aged flavor was higher for DBL than for DBI with WBL and WBI intermediate. Dry aging strip loins increase aged flavor yet did not improve beefy flavor compared to wet aging. Based on objective data and panelist's scores for tenderness, juiciness and aged flavor, a boneless, 28days wet aged strip steak, cooked to 71°C would provide the best combination of eating satisfaction and value.

Stereochemical studies on medicinal agents. 21. Investigation of the role of conformational factors in the action of diphenylpropylamines. Synthesis and analgetic potency of 5-methylmethadone diastereomers.

The synthesis of racemic threo- and erythro-5-methylmethadone (3a and 3b, respectively) was carried out and the solution conformation of each isomer was investigated through pKa and NMR studies. The data indicate that 3a-HCl exists exclusively in an internally hydrogen-bonded conformation while the erythro isomer 3b-HCl is present as a mixture of conformations. The erythro racemate 3b was found to possess 5.4 times the analgetic potency of (+/-)-methadone in contrast to the threo racemate 3a which was inactive and devoid of antagonist activity. The fact that the inactive racemate 3a contains the 5S,6R stereoisomer, which combines the configurations found in the more active enantiomers of methadone and isomethadone, suggests that the chiral centers do not behave as independent units and that conformational factors are playing an important role in governing stereoselectivity. These results, when analyzed together with earlier reports, suggest that one of the pharmacophoric conformations of the diphenylpropylamine analgetics possesses an antiperiplanar-like disposition of the Ph2CCOEt and +NHMe2 groups.

Short- and long-term influence of perinatal dexamethasone treatment on swine growth.

The objective was to evaluate the effects of perinatal dexamethasone (Dex) treatment on postnatal growth in pigs. Experiment 1: 42 piglets were assigned according to birth weight and sex to receive either Dex (1 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1h of birth. Body weights were recorded weekly and at sacrifice (day 18). Birth weights (1.43 +/- 0.05 kg) did not differ between treatment groups (P > 0.19). At day 18, Dex pigs were heavier than Control pigs (5.46 +/- 0.24 and 4.45 +/- 0.26 kg, respectively). Serum IGF-1 was 17.3% higher in Dex pigs (P < 0.04) compared to Controls. For serum GH, there was a treatment x sex interaction (P < 0.04) with GH being 51% lower in Dex males compared to Control males, and no differences in females. Experiment 2: 71 pigs were assigned according to birth weight and sex to receive either Dex (2 mg/kg body weight) or sterile saline (Control; equivalent volume) i.m. within 1 h of birth. Body weights were recorded weekly until weaning (day 21) and then every 14th day until market weight. Birth weights (1.53 +/- 0.03 kg) did not differ (P > 0.35) between treatment groups or sexes. Dexamethasone increased growth from birth to market weight by 4.15%. Carcass weights were not different (P > 0.34) between Dex (89.9 +/- 1.17 kg) and Control pigs (88.6 +/- 1.36 kg). Overall, Dex enhanced growth in pigs from birth to market weight with minimal effects on carcass and meat quality.

Creatine monohydrate supplemented in swine finishing diets and fresh pork quality: I. A controlled laboratory experiment.

Creatine monohydrate (CMH) was fed during the final stage of growth to determine its effects on fresh pork quality. Twenty-four Duroc-sired market hogs (107 kg) were individually penned and fed a corn-soybean finishing diet containing 0.55% lysine with 2% added choice white grease. Treatments consisted of a control diet (control) tested against two durations of CMH-supplemented diets (25 g CMH x pig(-1) x d(-1)) fed for 5 (5 d) or 10 (10 d) d before slaughter. Eight pigs were used per treatment. Pigs were slaughtered on day 11 of treatment (118 kg). Postmortem pH was measured in the loin (10th rib) and ham semimembranosus at 45 min (pH1) and 24 h (pH2). At 24 h, Hunter L* values were taken at the 10th rib and the ham semimembranosus. At 48 h, drip loss was determined from the loin (8th rib) and semimembranosus. Percentage of moisture, crude fat, and crude protein were determined for loin (9th rib) and semimembranosus. Treatment 2 semimembranosus tended to have a higher pH1 (P = 0.083) and pH2 (P = 0.05) than controls. Although not statistically different, 10 d semimembranosus had the highest proportion of moisture and lowest CP:moisture ratio, suggesting greater myofiber hydration. No statistical differences were detected across treatments for loin pH1, pH2, CP:moisture, or drip loss. Loins and semimembranosus from 5 d pigs had a numerically higher proportion of chemically determined i.m. fat, suggesting optimal intramuscular creatine phosphate saturation may allow for more energy to be stored as i.m. fat. Standard deviations of ham L* value means for 5 d (SD = 2.53) and 10 d (SD = 2.05) were 26 and 48% lower than controls (SD = 3.95). Standard deviations of loin L* value for 5 d (SD = 2.53) and 10 d (SD = 2.53) were 51 and 64% lower than controls (SD = 1.86). These results suggest that CMH supplementation buffers early postmortem and ultimate pH decline in the semimembranosus, which may reduce 48-h moisture loss.

Bioelectrical impedance analysis for the prediction of fat-free mass in lambs and lamb carcasses.

Ninety-eight commercial crossbred lambs, average weight 55.1 kg (+/- 4.95), were used to evaluate bioelectrical impedance analysis (BIA) as a prediction method for fat-free tissue from live lambs and lamb carcasses. Lambs were transported to the abattoir, restricted from feed for 10 h, weighed (LWt), and measured for body resistance (Rs, ohms), body reactance (Xc, ohms), and distance between detector terminals (L, cm). Following slaughter, hot carcasses were weighed (HCWt; average 31.4 +/- 2.8 kg) and impedance measurements of Rs, Xc, and L were recorded from readings on the dorsal and lateral sides of the carcasses. Temperatures (average = 39.2 degrees C) were recorded. Carcasses were chilled for 24 h. Cold carcass weights (CWt; average 31.1 +/- 2.8 kg) and temperatures (average = 1.0 degrees C) were recorded and BIA measurements were repeated. Carcasses were split down the midline and right sides were ground three times and sampled for chemical analysis of fat, moisture, ash, and protein. Fat-free mass (FFM) was calculated as [Wt-(Wt x %Fat)]. Fat-free soft tissue (FFST) was calculated as the sum of carcass chemical protein and carcass water. Regression equations predicting fat-free tissue for the live lambs (FFMlive and FFSTlive), hot carcasses (FFMhot and FFSThot), and cold carcasses (FFMcold and FFSTcold) were developed. The independent variables LWt, Rs, and Xc accounted for 77.7% (residual mean square error [RMSE] = 1.97 kg) of the variation in FFMlive and 78.6% (RMSE = 1.78 kg) of the variability of FFSTlive.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromagnetic scanning of pork carcasses in an on-line industrial configuration.

The objective of this study was to test and validate electromagnetic scanning of whole pork carcasses in an on-line, integrated, industrial configuration. The electromagnetic (EM) scanner was installed in two pork processing facilities (Plant A and Plant B). Plant A was a small pork fabrication plant that further processed chilled pork carcasses. Carcasses were delivered to Plant A by refrigerated trucks. The amount of EM energy absorbed by the carcasses was recorded as they were conveyed through the EM field. A plot of the absorption units over time (EM scan curve) was used to obtain predictive variables for estimating carcass and primal cut composition. Forty-eight whole, chilled carcasses (Group A) were electromagnetically scanned and conveyed onto the fabrication line. The average percentage carcass lean for Group A was 49.1% (range = 36.5 to 59.5%). Right carcass sides were removed from the processing line, fabricated into primal cuts, and dissected into fat, lean, and bone. Prediction equations were developed from EM scans for weight of total dissected carcass lean (R2 = .830; root mean square error = 1.80 kg), percentage of carcass lean (R2 = .820; root mean square error = 2.29%), and weight of dissected ham, longissimus muscle, and shoulder lean. In Plant B, the electromagnetic scanner was installed at the end of a pork slaughter line to ensure carcass scanning at a consistent carcass temperature. Fifty whole, pre-rigor eviscerated carcasses (Group B) were electromagnetically scanned before entering the chill cooler where fat and loin tissue depths were obtained by an optical grading probe. The average percentage carcass lean for Group B was 46.7% (range = 30.1 to 57.3%). Prediction equations were developed from EM scans for weight of total dissected carcass lean (R2 = .904; root mean square error = 1.59 kg), percentage of carcass lean (R2 = .863; root mean square error = 2.05%), and weight of dissected ham, loin, and shoulder lean. Statistical equations developed for the prediction of dissected primal cut lean were superior from EM scans of Group B (prerigor) carcasses. Electromagnetic scanning proved more statistically efficient than optical probes for predicting weight of dissected carcass lean and percentage of carcass lean. Statistical comparison of EM scan equations from Groups A and B are not completely valid because two different populations of carcasses were tested at different times of the year. The results of this study show that EM scanning has the potential to accurately predict pork carcass composition in a fully automated, on-line industrial configuration.

Creatine monohydrate supplemented in swine finishing diets and fresh pork quality: III. Evaluating the cumulative effect of creatine monohydrate and alpha-lipoic acid.

The objective of this study was to evaluate short-duration supplementation of alpha-lipoic acid (ALA) and creatine monohydrate (CMH) to improve fresh pork quality. Forty-eight commercial hybrid barrows were blocked by BW and randomly allotted to one of four treatments: 1) no CMH or ALA; 2) supplementation of 24 g of CMH(-1) x pig(-1) x d(-1); 3) supplementation of 600 mg ALA(-1) x pig(-1) x d(-1); or 4) combined CMH and ALA supplements. Twelve pigs per treatment were individually penned with ad libitum access to water and a finishing diet. Treatments were hand-fed to individual pigs daily (divided into three equal doses) for 5 d before slaughter at 113 kg BW in two separate groups of 24 pigs each. Intramuscular pH was recorded at 45 min postmortem and again at 24 h in the ham semimembranosus (SM) and the longissimus muscle (LM) between the 10th and 11th rib. A Meatcheck (SFK Technology, Peosta, IA) conductivity probe was inserted in the same anatomical locations as pH measurement, providing an index value (PY) from 0 to 100 (a higher index value indicates more intact muscle cells and higher water-holding capacity). Color (L, a, b values) measurements were obtained at 24 h postmortem on the ham gluteus medius (GM), SM, and LM. Two 2.54-cm-thick loin chops were removed from the loin for determination of Warner-Bratzler shear force and glycolytic potential. The intact SM and the posterior portion of the boneless loin were vacuum-packaged and stored for 7 d to determine purge loss. Creatine-supplemented pigs had a higher (P = 0.03) PY value in the SM (66.67) at 45 min postmortem than either ALA, singularly (63.50), or in the combined CMH/ALA (62.27) treatments. (A higher PY index indicates superior water-holding capacity.) Lipoic acid supplementation resulted in the highest pH at 45 min (P = 0.029). These results justify further evaluation of the potential positive influence of supplementing alpha-lipoic acid to improve pork quality.

Creatine monohydrate supplemented in swine finishing diets and fresh pork quality: II. Commercial applications.

The objectives of this study were to determine the value of supplementing creatine monohydrate (CMH) in a complete swine finishing ration and determining its effects on meat quality. Crossbred barrows (n = 59) were allotted five pens per treatment with three pigs per pen. Dietary treatments, including 20 g CMH x pig(-1) x d(-1) fed for 5, 10, or 15 d before slaughter, were compared to control pigs that received no CMH. The basal diet was a corn-soybean meal finishing diet. At 123.5 kg, pigs were delivered to a commercial packing plant (80 km) and slaughtered according to industry practices. After a 24-h chill at 4 degrees C, right-side loins were collected from the fabrication line and vacuum-packaged for delivery to the University of Missouri Meat Lab. Hams were scanned for lean content by a primal cut electromagnetic scanner. After scanning, ham pH and light reflectance (L*, a*, b*) were obtained on the gluteus medius muscle. Loin pH and light reflectance were obtained at the 10/11th-rib juncture. The posterior section of the boneless loin was weighed, vacuum-packaged, and stored for 7 d at 1 degree C. After aging, light reflectance, weights, and Warner/Bratzler shear force measurements were taken. A linear trend (P = 0.071) was observed for ham 24-h L* values, and a cubic trend was observed for ultimate loin pH (P = 0.102). Hunter L* values of the longissimus possessed a negative linear contrast (P = 0.009) after aging, revealing that the loins of those animals treated for 10 and 15 d exhibit higher L* values. A cubic trend (P = 0.057) was shown for percentage of moisture lost as purge; 5- and 10-d treatments were intermediate to control and 15-d treatments. Warner/Bratzler shear force measurements for chops aged 7 d increased in a linear fashion (P = 0.024). This data suggests that 5-d supplementation of CMH before slaughter improves several pork quality attributes. However, it seems that supplementing CMH in swine diets for 10 or 15 d could reduce the quality of fresh pork.

Pork carcass composition derived from a neural network model of electromagnetic scans.

We used an advanced computer logic system (NETS 3.0) to decipher electromagnetic (EM) scans in lieu of traditional linear regression for estimation of pork carcass composition. Fifty EM scans of pork carcasses were obtained on-line (prerigor) at a swine slaughter facility. Right sides were cut into wholesale parts and dissected into fat, lean, and bone to obtain total dissected carcass and primal cut lean. In this study, the input layer consisted of 81 nodes (80-point EM scan curve and warm carcass weight), one hidden layer of 42 nodes, and an output layer consisting of one node, which were run separately for outputs of ham, loin, or shoulder lean. The hidden layer connected to the output of total lean contained 50 nodes. Thirty-five scans were used for training of the network. The new network was then tested with 15 previously unseen input/output pairs. Separate neural networks were developed for the estimation of dissected total carcass, ham, loin, and shoulder lean. The NETS configuration improved on linear regression equations for estimation of total carcass lean by .31 kg, ham lean by .284 kg, and shoulder lean by .148 kg. Our results show that advanced computer logic systems have the capacity to improve upon traditional linear regression equations for prediction of pork carcass composition.

Electromagnetic scanning to predict lamb carcass composition.

The electromagnetic scanner generates a constant, low-level electromagnetic field (2.5 MHz) within a large plexiglass tube. The amount of electromagnetic (EM) energy transferred (to the carcass) is highly related to lean tissue. A plot of the absorption units over distance can be used to assess the total mass of lean tissue and of the respective primal cuts. The difference in curve height between two points (D), peak phase absorption, and linear carcass measurements (pre-rigor, HCWT or post-rigor, CWT carcass weight, and carcass length, LENG) were used to predict total dissected lean (TOTLEAN), dissected leg lean (LEGLEAN), and percentage of dissected carcass lean (PERLEAN). Twenty-one pre-rigor and 22 post-rigor (24 h chill) lamb carcasses, average weight 26.8 (+/- 4.2 kg) and 26.4 (+/- 4.1 kg) kg, respectively, were evaluated from measurements of total body electrical conductivity (TOBEC). Two geometric orientations were tested for statistical accuracy in this study: A) each carcass entered the EM tunnel rear leg first, on its left lateral side, neck facing the right side of the tunnel; and B) each carcass entered the EM tunnel rear leg first, breast down, and neck up. Orientation A proved more statistically efficient for pre-rigor carcasses, and orientation B was more desirable for post-rigor carcasses. Multiple-regression models involving HCWT, LENG, and a single D measure accounted for 98.0 and 95.0%, respectively, of the total variation in pre-rigor carcass TOTLEAN and LEGLEAN in A.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of the antioxidant lipoic acid on beef longissimus bloom time.

The objective of this study was to evaluate the influence of lipoic acid (LA) on beef LM steak bloom time, as well-as to characterize bloom time in the CIE L*, a*, and b* color space over a 93-min period. Thirty-two Simmental steers were supplemented with LA for 21 d immediately before slaughter at levels of 0, 8, 16, or 24 mg of LA/kg BW (eight steers per treatment). Lipoic acid was mixed with liquid paraffin, allowed to solidify, prilled, and top-dressed over a standard finishing diet. Steers were slaughtered at the University of Missouri abattoir in four groups of eight (two steers per treatment) over a 2-wk period. After a 24-h chill at 4 degrees C, the right LM was removed from each carcass. One 2.54cm steak was removed from the anterior portion of the LM, and its color characteristics (CIE L*, a*, and b*) were measured immediately with a standardized spectrocolorimeter. Color measurements were taken every 3 min thereafter for a total of 93-min. Hue angle (true red) and chroma (color saturation) were calculated from the color measurements. Addition of LA to the diet had no effect on bloom time (P = 0.67). When treatment means were analyzed, the addition of 24 mg of LA/kg BW to the diet resulted in higher (lighter) L* values (P < 0.05) compared with other treatments, whereas the addition of 16 mg of LA/kg BW to the diet caused lower hue angles (more true red; P < 0.05) when compared with other treatments. Addition of LA to the diet did not affect a* (P = 0.13) and b* (P = 0.18) values or chroma (P = 0.62). In the absence of treatment effects, bloom times for all treatments were pooled, and L* values did not change (P > 0.05) during the 93-min bloom time; however, a* and chroma values increased for 9 min and plateaued after 12 min (P < 0.01). Similarly, b* values increased (P < 0.01) for the first 6 min, and after 9 min, no further increase in yellowness was detected. Bloom time had little effect on hue angle, which stabilized after 3 min. Supplementing steers with the antioxidant LA for 21 d had no effect on the bloom time of beef LM; however, higher levels of supplemental LA affected L* values and hue angles of beef.

Evaluation of electronic technology to assess lamb carcass composition.

Accurate price signals are essential for producers of American lamb to ensure production of uniformly lean animals. Development of carcass merit-pricing systems will require the use of objective technology for assessing carcass composition or lean distribution. The objective of this study was to evaluate electronic technologies for accurate determination of lamb carcass composition. Lambs (n = 106) were selected as a representation of U.S. market lambs that transcended geographic location, sex, breed, carcass weight, yield grade, and production system. The independent variables used to predict lamb composition varied with the technology. The electronic technologies tested included realtime ultrasound, optical reflectance probe, bioelectrical impedance analysis, and electromagnetic scanning (TOBEC). All technologies, except realtime ultrasound, were tested on warm (prerigor) carcasses and repeated after a 24-h chill. Longitudinal ultrasonic scans of fat and muscle tissue depth and grading probe fat depths were marginal predictors of proportional carcass yield. The TOBEC measurements often accounted for more variability associated with kilograms of dissected lean and percentage of carcass lean than did carcass weight. Equations from TOBEC measurements were the most accurate predictors of weight and percentage of dissected and fat-free lean. Bioelectrical impedance measurements of resistance and reactance combined with carcass weight were also good predictors of carcass composition. Prediction of carcass lean distribution by measures of TOBEC were the most accurate for prediction of leg lean. The implications of usefulness of these technologies will depend on the commitment of the U. S. sheep industry in development of a lamb price discovery system based on carcass composition.

Assessment of lamb carcass composition from live animal measurement of bioelectrical impedance or ultrasonic tissue depths.

Market weight lambs, average weight 52.5 kg (+/-6.1), were used to evaluate nontraditional live animal measurements as predictors of carcass composition. The sample population (n = 106) represented U.S. market lambs and transcended geographic location, breed, carcass weight, yield grade, and production system. Realtime ultrasonic (RU) measurements and bioelectrical impedance analysis (BIA) were used for development and evaluation of prediction equations for % boneless, closely trimmed primal cuts (BCTPC), weight or % of dissected lean tissue (TDL), and chemically derived weight or % fat-free lean (FFL). Longitudinal ultrasonic images were obtained parallel to the longissimus thoracis et lumborum (LTL), positioning the last costae in the center of the transducer head. Images were saved and fat and LTL depths were derived from printed images of the ultrasonic scans. Bioelectrical impedance analysis was administered via a four-terminal impedance plethysmograph operating at 800 microA at 50 kHz. Impedance measurements of whole-body resistance and reactance were recorded. Prediction equations including common linear measurements of live weight, heart girth, hindsaddle length, and shoulder height were also evaluated. All measurements were taken just before slaughter. Bioelectrical impedance measurements (as compared to RU and linear measurements) provided equations for %BCTPC, TDL, %TDL, FFL and %FFL with the highest R2 and lowest root mean square error. Even though BIA provided the best equations of the three methodologies tested, prediction of proportional yield (%BCTPC, %TDL, and %FFL) was marginal (R2 = .296, .551, and .551, respectively). Equations combining BIA, RU, and linear measurements greatly improved equations for prediction of proportional lean yield.

Creatine monohydrate supplementation and the quality of fresh pork in normal and halothane carrier pigs.

The objective of this research was to examine the impact of supplementation with creatine monohydrate (CMH) on the quality of various muscles from normal and heterozygous halothane carrier pigs. Twenty-nine crossbred pigs, 16 normal (NN) and 13 halothane carrier (Nn) genotypes, were supplemented with 0 or 25 g x pig(-1) x d(-1) of CMH for 5 d before slaughter. Supplemented pigs gained 2.26 kg more weight (P < 0.05) during 5 d of supplementation. There were trends (P < 0.10) toward higher objective marbling scores and lower cooking loss for supplemented pigs. The 45-min pH was 0.27 units higher (P < 0.05) for supplemented pigs in the semimembranosus; CMH supplementation did not influence (P > 0.05) drip loss or muscle composition. Supplementation with CMH also resulted in lower L* values in two ham muscles, semitendinosus (5.15 units) (P < 0.05) and semimembranosus (1.95 units) (P < 0.10) for Nn carcasses. Genotype had significant effects on most quality indicators, with Nn carcasses producing lower-quality lean as evidenced by less desirable subjective and objective color and higher drip losses. Genotype also affected the composition of several muscles, with the NN carcasses having more fat and less moisture.

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, 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 > 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 R2 of 0.80. Loins from CLA-supplemented pigs exhibited increased lean weight (P < 0.05) and PMA values (P < 0.05) compared to controls. Lean prediction of loins by TOBEC resulted in an R2 of 0.66. Bellies from CLA-supplemented pigs had a higher percentage of moisture (P < 0.03) and protein (P < 0.01) and decreased percentage of lipid (P < 0.01). The R2 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.

Serum concentrations of leptin in six genetic lines of swine and relationship with growth and carcass characteristics.

The objective of this study was to evaluate the relationship between serum concentrations of the hormone leptin with growth and carcass traits insix distinct breeds of pigs entered into the 2000 National Barrow Show Sire Progeny Test. Breeds evaluated were Berkshire (n = 131), Chester White (n = 33), Duroc (n = 40), Landrace (n = 23), Poland China (n = 26), and Yorkshire (n = 41). Serum samples were collected and assayed for concentrations of leptin at entry into test (On-Test Leptin) at 34 +/- 6.7 kg of live weight and again 24 h prior to harvest (Off-Test Leptin) at 111 +/- 3.1 kg of live weight. Carcass measurements taken included hot carcass weight, carcass length, backfat, longissimus muscle area (LMA), longissimus pH, Hunter L-value, chemically determined intramuscular fat (IMF), and subjective color, marbling, and firmness scores. Average daily gain, IMF percentages, and water-holding capacity (WHC) were also determined. On-Test Leptin concentrations were not different (P > 0.10) between swine breeds; however, Off-Test Leptin concentrations did differ (P < 0.001) across genotype. Berkshire had the greatest Off-Test Leptin concentrations (6.58 +/- 0.43 ng/mL), and Duroc and Yorkshire had the lowest (3.49 and 3.96 +/- 0.68 ng/mL; respectively). In addition, Off-Test Leptin concentrations were correlated with average daily gain (r = 0.29; P < 0.001), last-rib fat thickness (r = 0.48; P < 0.001), 10th rib backfat (r = 0.52; P < 0.001), LMA (r = -0.33; P < 0.001), percent fat-free carcass lean (r = -0.51; P < 0.001), and WHC (r = 0.15; P < 0.05). Off-Test Leptin concentrations also differed by gender, with barrows having greater (P < 0.001) serum concentrations of leptin than gilts (6.55 +/- 0.48 vs 3.35 +/- 0.44). Differences exist between breeds of pigs in a manner consistent with breed-specific traits for growth, leanness, and quality; thus, leptin may serve as a useful marker for selection or identification of specific growth and carcass traits.

Alternative pork carcass evaluation techniques: I. Differences in predictions of value.

Dissected and predicted wholesale and lean boneless values for 154 pork carcasses representing seven genotypes with substantial variation in carcass composition and percentage of lean were determined. Dissected carcass value was determined using a component pricing model, and four alternative models were specified to predict that value. The models included measurements from a ruler (RULER) and two carcass evaluation technologies, Hennessy probe (PROBE) and electromagnetic scanner (EMS1). A combination of the PROBE and EMS1 models (EMS2) was also used. For wholesale value, R2 were .40, .70, .59, and .74, and the RSD were 8.18, 5.77, 6.76, and 5.38 ($/100 kg of carcass value) for RULER, PROBE, EMS1, and EMS2, respectively. For lean boneless value, the R2 were .41, .73, .59, and .74, and the RSD were 8.34, 5.67, 6.99, and 5.51 ($/100 kg of carcass value) for RULER, PROBE, EMS1, and EMS2, respectively. The results indicate that a combination of probe and electromagnetic scanner measurements provided the best fit to dissected value.