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Effect of commercial transport in Spain on cattle welfare and meat quality.

The purpose of this work was to determine the effect of transport of cattle from the farm to the abattoir on the animal's welfare and post mortem meat quality (instrumental and sensorial). Thirty-nine commercial journeys were followed in Spain from July 2000 to July 2001 at varying distances from a local abattoir in the city of Zaragoza. Blood samples were taken at the farm and at sticking and meat pH24 was measured at 24 hours post-mortem. Samples from the M. longissimus dorsi thoracis were taken from 48 slaughter bulls and analysed in terms of instrumental and sensorial qualities. Cortisol, glucose, CPK, lactate and N:L ratio increased during transport compared to control values. Cortisol was higher after 1-2 h transport compared to journeys that were less than 1 h or more than 2 h long. In general the parameters indicated slightly more stressful conditions under winter conditions than in the summer. Meat tenderness measured by a Warner-Bratzler device demonstrated that there was no significant effect of either transport time or season. There was no significant change in pH24 or meat colour at 24 h with transport time. Transport time had a significant effect (p < 0.05) on overall liking and animals transported in summer had slightly more tender meat and higher overall liking.

Abattoirs↗

Carcass and meat quality characteristics and backfat fatty acid composition of swine as affected by the consumption of peanuts remaining in the field after harvest.

Carcass composition, meat quality characteristics and changes in backfat fatty acid composition of swine that were allowed to obtain part or all of their weight gain during the growing-finishing period from gleaning peanuts remaining in the field after harvest were evaluated. Thirty-six cross-bred pigs (18 barrows, 18 gilts) were allotted evenly among the following six treatments: 1) fed a corn-soybean meal-based diet (C) from 26 to 104 kg (CCC); 2) gleaned peanuts (P) from 26 to 102 kg (PPP); 3) C from 26 to 78 kg and P from 78 to 103 kg (CCP); 4) P from 26 to 55 kg and C from 55 to 105 kg (PCC); 5) C from 26 to 56 kg and P from 56 to 103 kg (CCP); 6) P from 26 to 79 kg and C from 79 to 106 kg (PPC). Carcasses from all treatment groups were similar in composition. Carcass fat of pigs in CPP, PPC and, in particular, PPP groups was softer than that from pigs in CCC, CCP and PCC groups. Ratio of unsaturated to saturated fatty acids in backfat increased in proportion to the amount of weight gained while pigs gleaned peanuts. Loins from pigs in the PPP and CPP treatment groups received lower marbling scores than those from the CCC group, but the fat content of the loin was not affected by treatment. No differences were detected between treatment groups in shear force values or sensory panel attributes of broiled loin chops, or in thiobarbituric acid values of vacuum packaged loin sections frozen for 4 mo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

Effects of increasing dietary niacin on growth performance and meat quality in finishing pigs reared in two different environments.

We conducted two experiments to determine the effects of added dietary niacin on growth performance and meat quality in finishing pigs. Pigs were blocked by weight and assigned to one of six dietary treatments in both experiments. Dietary treatments consisted of a corn-soybean meal-based control diet (no added niacin) or the control diet with 13, 28, 55, 110, or 550 mg/kg of added niacin. In Exp. 1, pigs were housed at the Kansas State University research from with two pigs per pen (six pens per treatment per sex). In Exp. 2, pigs were housed with 26 pigs per pen (four pens per treatment per sex) in a commercial research barn. In Exp. 1, 144 pigs (initially 51.2 kg) were fed diets in two phases (d 0 to 25 and 25 to 62) that were formulated to 1.00 and 0.75% lysine, respectively. In Exp. 2, 1,248 pigs (initially 35.9 kg) were fed diets in four phases (d 0 to 28, 29 to 56, 57 to 84, and 85 to 117), with corresponding total lysine concentrations of 1.25, 1.10, 0.90, and 0.65% lysine, respectively. Added fat (6.0%) was included in the first three phases. In Exp. 1, average daily feed intake tended (quadratic, P < 0.07) to increase then return to values similar to control pigs as dietary niacin increased. Longissimus muscle (LM) 24-h pH (longissimus of pigs fed added niacin) tended to increase (control vs niacin, P < 0.06) for pigs fed added niacin. In the commercial facility (Exp. 2), increasing added niacin improved gain:feed (quadratic, P < 0.01) and subjective color score, and ultimate pH (linear, P < 0.01). Added niacin also decreased (linear, P < 0.04) carcass shrink, L* values, and drip loss percentage. Results from these two studies show that 13 to 55 mg/kg added dietary niacin can be fed to pigs in a commercial environment to improve gain:feed. It also appears that pork quality, as measured by drip loss, pH, and color, may be improved by higher concentrations of added dietary niacin.

Animal Feed↗

Evaluation of recombinant porcine somatotropin on growth performance, carcass characteristics, meat quality, and muscle biochemical properties of Belgian Landrace pigs.

The dose related effects of recombinant porcine somatotropin (rpST) on growth, carcass characteristics, muscle properties, and meat quality were investigated in lean Belgian Landrace finishing pigs. Ninety-six pigs (48 barrows and 48 gilts) were injected daily with either vehicle, 1.5, 3, or 6 mg of rpST from 60 to 97.5 kg live weight. Each treatment group consisted of six pens of four pigs each (two of each sex). Pigs were given ad libitum access to a high-protein (20.4% CP) cereal-based diet. Administration of rpST increased (P less than .05) growth rate (16.3 to 25.4%) and improved (P less than .05) feed efficiency (16.9 to 29.4%). Feed consumption was reduced (12%; P less than .05) only in the 6 mg of rpST group. Liver, kidney, and heart weights were increased (P less than .05) in the 3 and 6 mg of rpST groups. Although the Belgian Landrace pigs are bred for superior carcass quality, rpST further improved (P less than .05) carcass composition at all dose levels as evidenced by a reduction (10 to 50%) in a number of subcutaneous fat depth measurements, an increase (10 to 20%) in longissimus muscle area, and an improvement in the lean cut:fat cut ratio. Rate of pH decline in the gluteus and longissimus muscles was similar, but rapid, in all groups (pH after 30 min = 5.74 to 5.94); the ultimate (24 or 72 h) pH was .15 to .2 pH units higher (P less than .05) in the pigs that received the 3 and 6 mg of rpST doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗

Reduction of stress-induced changes in meat quality with thermolysed brewer's yeast of high nucleotide content in pigs.

The effect exerted by a biogenic performance enhancer of high nucleotide content on meat quality in 20 Norwegian Landrace pigs (90 to 95 kg) was examined. The diet of the treated group was supplemented with the performance enhancer for the last 30 days of fattening. The stress effect was transport to the slaughterhouse and slaughter itself. Plasma creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) activities, glucose and cortisol concentrations, and muscle pH were determined. Serious stress damage was found in the cardiac and skeletal muscle, as indicated by the high CK (980 U/L), LDH (> 1600 U/L) and AST (67 U/L) activities in the untreated group; values were significantly lower in the experimental pigs (458, 468 and 17 U/L, respectively). There were no significant differences in glucose and cortisol concentrations between the two groups. In the control group the pH values were significantly lower and more muscle samples showed PSE character than in the treated group (75 and 30%, respectively).

Animals↗

Effect of conjugated linoleic acid on meat quality, lipid metabolism, and sensory characteristics of dry-cured hams from heavy pigs.

We investigated conjugated linoleic acid (CLA) supplementation administered to heavy pigs, assessing carcass characteristics, meat quality, and sensory characteristics of dry-cured (Parma) ham. Thirty-six pigs, averaging 97 kg BW, were assigned randomly to three feeding groups in which diets were supplemented with either 0, 0.25, or 0.5% (as-fed basis) of a CLA preparation containing 65% CLA isomers. All pigs were slaughtered at 172 kg BW. No (P > 0.05) differences were observed in dressing percentage, loin and ham weight, or pH and color of longissimus and semimembranosus muscle. Tenth-rib backfat thickness tended to be lower (P < 0.10) in carcasses from CLA-fed pigs. The oxidative stability of longissimus muscle was greater (P < 0.05) in pigs fed CLA than control, but only at the longer (300 min) oxidation time. Acetyl-CoA carboxylase activity in adipose tissue of CLA-fed pigs was less (P < 0.05) than that of pigs fed diets devoid of supplemental CLA. Composition of ham fat was markedly affected (P < 0.01) by dietary CLA, with higher saturated fatty acids, lower monounsaturated fatty acids, and higher CLA in the fat of CLA-fed pigs regardless of supplementation level. Although melting quality was improved (P < 0.05), most sensory characteristics and the chemical composition of dry-cured hams were not (P > 0.05) affected by incorporation of CLA. Results indicated that dietary CLA alters lipid metabolism, producing lower concentrations of monounsaturated fatty acids and increased concentrations of CLA isomers in the fat of heavy pigs. Moreover, supplementing diets with CLA produced only minimal improvements in Parma ham sensory traits and had no appreciable effects on fresh pork quality.

Adipose Tissue↗

Muscle metabolism and meat quality of Pectoralis from turkeys treated with postmortem electrical stimulation.

This experiment was conducted to evaluate the effects of electrical stimulation (ES) on muscle metabolism and breast meat quality in turkeys. Thirty-six turkey hens were either ES at the neck in a saline bath (570 V, 450 mA, AC, 60 Hz, 2 s on 1 s off for 10 pulses) or used as unstimulated controls. One breast fillet from all carcasses was harvested at 2 h postmortem. The opposite fillet was harvested from the ES carcasses at 8 h postmortem and from the unstimulated controls at either 8 or 24 h postmortem. All fillets were sampled at time of deboning for expressible moisture, pH, R-value, gravimetric fragmentation index (GFI), and sarcomere length. The remainder of the fillet and the samples for GFI and sarcomere length were aged on ice until 24 h postmortem. After aging, fillets were analyzed for cook loss and shear value. Color was measured at time of deboning and at 24 h postmortem. Electrical stimulation accelerated rigor mortis development as indicated by significantly lower pH values and higher R-values at 2 h postmortem when compared to control fillets. The pH and R-values of the 2-h ES treatment were not significantly different from the 8-h ES, 8-h controls, or the 24-h controls. Fillets from carcasses that were ES and deboned at 2 h had significantly longer sarcomeres than the 2-h controls; however, there were no significant differences between the 2-h ES and the 8-h ES treatments, 8-h controls, or the 24-h controls. Although ES accelerated muscle metabolism at 2 h postmortem, it had no effect on shear value, expressible moisture, cook loss, GFI, L*, or a* color values. These results suggest that this postmortem ES system would not benefit turkey processors.

Animals↗

Comparison of a Modified Atmosphere Stunning-Killing System to conventional electrical stunning and killing on selected broiler breast muscle rigor development and meat quality attributes.

Two experiments were conducted to compare the effects of a 70:30 argon:carbon dioxide Modified Atmosphere Stun-Kill (MASK) system to both a low voltage (LV) and a high current (HC) electrical stunning and conventional killing system on broiler breast rigor development and meat quality. In Experiment 1, the effects on breast muscle pH and meat tenderness of the MASK system and the LV system were compared. In Experiment 2, the MASK system was compared to both HC and LV stunning for pH, R-value, C.I.E. L*, a*, b*, cooked yield, and tenderness of broiler breast meat. In Experiment 1, there were no significant differences in breast muscle pH between LV and MASK, except at 24 h. Only at 5 h post-mortem did the MASK system result in significantly tougher breast meat. In Experiment 2, there were no significant differences between treatments in breast muscle color or cooked yield at any sampling time. The breast muscle from birds subjected to the HC stun had consistently higher pH values until 5 h post-mortem, at which time the breast meat from birds subjected to the MASK system had higher pH. R-value data showed a similar trend, with the HC stunned birds having the lower R-values until 5 h post-mortem. Breast meat tenderness values for the three treatments were significantly different only at 3 and 5 h post-mortem, when birds stunned with HC had the highest shear values. The MASK system did not exhibit any rigor accelerating benefits when compared to LV stunning and conventional killing, and only minimal rigor acceleration when compared to HC killing.

Abattoirs↗

Growth performance, dry matter and nitrogen digestibilities, serum profile, and carcass and meat quality of pigs with distinct genotypes.

We investigated the effect of distinct genotypes on growth performance, DM and N digestibilities, serum metabolite and hormonal profiles, and carcass and meat quality of pigs. Eight control-line and eight select-line pigs with an equal number of gilts and castrated males per genotype were chosen from the group of pigs subjected to selection for lean growth efficiency. Pigs were housed individually and allowed ad libitum access to common grower, finisher 1, and finisher 2 diets when they reached approximately 20, 50, and 80 kg, respectively, and water throughout the study. Although genotype had no effect on growth performance during the finisher 2 phase and overall, select-line pigs grew faster and more efficiently (P < 0.05) during the grower and finisher 1 phases than did control-line pigs. Dry matter and N digestibilities during the grower phase were lower (P < 0.05) in select-line pigs compared with control-line pigs. Select-line pigs had less ultrasound backfat (P < 0.05) at the end of the grower and finisher 2 phases. Serum urea N (P < 0.05) and leptin concentrations were lower in select-line pigs than in control-line pigs, but the effect of genotype on serum glucose, triglyceride, or insulin concentration was rather inconsistent. Select-line pigs had heavier heart (P < 0.05), liver (P = 0.08), and kidneys (P < 0.01), implying a higher metabolic activity. Less 10th-rib carcass backfat (P < 0.01) and a trend for larger carcass longissimus muscle area (P = 0.10) were reflected in the greater (P < 0.01) rate and efficiency of lean accretion in select-line pigs. Select-line pigs had lower subjective meat color (P < 0.01), marbling (P < 0.05), and firmness (P < 0.01) scores. Final serum leptin concentration was correlated positively with carcass backfat thickness (r = 0.73; P < 0.01) and negatively with overall feed intake (r = -0.77; P < 0.01). These results indicate that pigs with distinct genotypes exhibited differences in the growth rate, metabolite and hormonal profiles, and body composition. Further research is necessary to determine whether pigs with distinct genotypes respond differently to dietary manipulations, which would have an effect on developing optimal feeding strategies for efficient and sustainable pig production.

Adipose Tissue↗

Influence of dietary conjugated linoleic acid on growth, meat quality, lipogenesis, plasma leptin and physiological variables of lipid metabolism in rabbits.

We investigated the effects of conjugated linoleic acid (CLA) supplementation on growth, feed efficiency, carcass characteristics, meat quality, lipogenesis, and lipid metabolism in rabbits. One hundred forty-four New Zealand White rabbits, half males, half females, age 55 d, mean 1.8 kg BW, were randomly assigned to three weight- and sex-balanced feeding groups in which conventional pelleted diets were supplemented with 0, 0.25, or 0.5% of a CLA preparation. The CLA preparation contained 65% CLA isomers. Twelve rabbits (six males and six females from each group) were slaughtered at each of three slaughtering trials (2.5, 2.8, and 3.1 kg BW, or 76, 90, and 104 d of age). Conjugated linoleic acid supplementation did not influence growth performance (P > or = 0.05) or carcass characteristics but reduced perirenal fat at heavier slaughtering weights (P = 0.09 at 2.8 kg BW; P < 0.01 at 3.1 kg BW). Conjugated linoleic acid reduced acetyl-CoA-carboxylase (CBX) activity in liver (P < 0.05) and adipose tissues (P < 0.01) but did not influence malic enzyme (ME) or glucose-6-phosphate dehydrogenase activity. Significant differences were found between sex in interscapular fat (P < 0.05) for CBX, in perirenal (P < 0.01) and interscapular (P < 0.05) fat for ME, and a tendency (P = 0.070) in liver for glucose-6-phosphate dehydrogenase. The oxidative stability of longissimus lumborum muscle was increased at the higher level of supplementation (P < 0.05). Conjugated linoleic acid reduced (P < 0.05) triglycerides and total cholesterol in plasma with a trend to increased serum leptin (P = 0.06). Plasma triglycerides were higher in males than females (P < 0.01) and plasma leptin tended to be higher in females (2.57 vs. 2.13 ng/ml, P = 0.06). It is concluded that dietary CLA reduced carcass fat in rabbits slaughtered at 2.8 kg or above and altered lipid metabolism to produce lower concentrations of serum triglycerides and total cholesterol and higher concentrations of leptin.

Animal Feed↗

Economic values of optimum traits: the example of meat quality in pigs.

In this paper a method is outlined to derive marginal-income functions and to calculate economic values for traits with an intermediate optimum such as meat-quality traits. A normal distribution of the quality trait was assumed, but the method can be used for other distributions as well. The parameters necessary to use this method are distribution of the quality trait, population mean and the standard deviation of the quality trait, optimum range, and price differences between products within and outside the optimum range. Especially, the optimum range for the quality trait and the price differences to be used have to be derived from consumer and processing research. Some alternative methods that can be used for selection on quality traits, such as restricted selection index, desired-gains index, and indices based on a quadratic aggregate genotype, are discussed.

Animals↗

Genetic correlation between serum insulin-like growth factor-1 concentration and performance and meat quality traits in Duroc pigs.

This study was intended to examine whether serum IGF-I concentration is appropriate for use as a physiological predictor for genetic improvement of meat production and meat quality traits in pigs. Heritabilities and genetic correlations were estimated for these traits. The Duroc breed used in this study was selected for seven generations for average daily BW gain (DG) from 30 to 105 kg of BW, loin-eye muscle area (EM), backfat thickness (BF), and intramuscular fat (IMF) content. Serum IGF-I concentration of boars and gilts at the fourth generation of selection and that of boars, gilts, and barrows from the fifth to seventh generations of selection were measured at 8 wk (IGFI-8W) for 832 animals and again at the time they reached 105 kg of BW (IGFI-105KG) for 834 animals. A multivariate REML procedure was used to estimate genetic parameters with a model incorporating generation of selection, sex, common environmental effect of litter, and individual additive genetic effects. Heritability estimates for IGFI-8W and IGFI-105KG were 0.23 +/- 0.02 and 0.26 +/- 0.03, respectively. The estimates of common environmental effect for IGFI-8W and IGFI-105KG were 0.20 +/- 0.02 and 0.03 +/- 0.01, respectively. Positive genetic correlations were estimated between IGFI-8W and DG (0.26 +/- 0.08), EM (0.22 +/- 0.10), and IMF (0.32 +/- 0.10). Moreover, the positive genetic correlation between IGFI-105KG and EM was 0.42 +/- 0.08. These results indicate that serum IGF-I concentration at an early stage of growth was effective for prediction of IMF, but it was not a reliable physiological predictor of genetic merit of meat production traits.

Adipose Tissue↗

Effect of genotype, sex and rearing temperature on carcase and meat quality of guinea fowl.

1. The aim of our study was to analyse the effect of genotype (label and standard), sex and rearing temperature (simulating daily outdoor in the summer or winter) on the carcase and meat quality of guinea fowl. Using 20 animals per treatment, slaughtered at 96 d of age we measured the breast angle and the thickness of the skin on the wing membrane. Carcases were weighed and cut into parts according to a standardised procedure to determine the percentages of abdominal fat, breasts, wings and thighs with shanks. 2. At slaughter, standard guinea fowl were heavier than label guinea fowl and for both genotypes, the females were heavier than the males (+5.6%). The mean value of breast angle was 85 degrees. This value was significantly higher for the standard guinea fowls and for the females of both genotypes compared with males. Thus, female carcases, particularly standard females, were more compact. The skin was thicker for the standard guinea fowls (0.84 mm vs 0.77 mm) which could be due to more subcutaneous fat. 3. Carcase yield was higher for the males (68.7% vs 68.2%). The percentage of abdominal fat was higher for the standard guinea fowls (2.8% vs 2.4%) and for the females of both genotypes compared with males. The label guinea fowls had higher yields of breasts and thighs with shanks. For both lines, the breast and thigh meat of females was judged more tender and less stringy. 4. Low rearing temperature decreased growth performance but had no significant effect on carcase quality.

Abdomen↗

Impact of spontaneous exercise on performance, meat quality, and muscle fiber characteristics of growing/finishing pigs.

The objective of this experiment was to determine if increased space and exercise for finisher pigs (0.90 vs 9.45 m2/pig) affects performance, meat quality, or muscle fiber characteristics. Newsham barrows (n = 32, 4 pens/treatment) were placed in one of two space allocations: control space allowance (CONT) or in a long pen with increased space allowance (10x). Pigs were weighed every 28 d and feed intake/pen was calculated. Pigs were filmed for behavioral analysis on d 70 and 100 using video recorders to determine walking distances over a 24-h period. After a 5-h transport and 2-h rest period, pigs (approximately 115 kg) were slaughtered on the same day at a commercial facility. Muscle samples were obtained from the longissimus lumborum (LL) and semimembranosus (SM) muscles within 1 h postmortem for muscle fiber typing. Backfat thickness and pH decline were measured on the left side of each carcass. After 24-h chilling, a boneless loin was collected from each pig and stored at 2 degrees C until analyzed. On d 14 postmortem, loins were cut at the 10th rib for color evaluations, and chops were cut for Warner-Bratzler shear (WBS) force and sensory analysis. Histochemical staining methods were used for the detection of type I, IIA, and IIB/X muscle fiber types. There were no significant differences (P > 0.10) in live weight, ADG, ADFI, or G:F ratio of the two experimental groups evaluated. Pigs finished in 10x pens walked a greater (P < 0.01) distance over a 24-h period than pigs finished in the CONT pens. Pigs finished in the lOx pens were fatter (P < 0.05) at the last lumbar vertebra than pigs finished in the CONT pens, but no significant differences were found in loineye area, loin color, marbling scores, WBS, sensory panel scores, retail display measures, or muscle fiber type percentages. Expanded space allowance to increase exercise resulted in no improvements in pig performance, pork loin measures, or muscle characteristics.

Animal Husbandry↗

Endocrine, blood metabolite, and meat quality changes in goats as influenced by short-term, preslaughter stress.

The purpose of this study was to determine the effects of short-term, preslaughter stress on physiological responses and meat quality in goats of different age groups. The goats (n = 28) were classified into young (6 to 12 mo of age) and old (24 to 30 mo of age) groups, feed deprived overnight, and slaughtered at three different times (replicates). On each slaughter day, goats were either subjected to a 2-h transportation stressor (TS) or remained unstressed in holding pens (NS) before slaughter. Blood samples were collected via jugular venipuncture from TS and NS goats at 2, 1, and 0 h before slaughter. Muscle glycogen and pH were measured on samples from longissimus muscle (LM) collected at 15 min and 24 h postmortem, and instrumental measures of meat color were obtained on the LM after a 24-h chilling period at 4 degrees C. The TS goats had higher plasma cortisol (P < 0.01) and glucose (P < 0.05) concentrations than NS goats. The rates of increase in plasma cortisol, glucose, and nonesterified fatty acid concentrations were greater in TS than in NS goats (stressor treatment x blood sampling time, P < 0.01). Muscle glycogen concentrations were greater (P < 0.05) in NS than in TS goats and higher (P < 0.01) in old vs. young goats; however, pH measured at 15 min and 24 h postmortem was not (P > 0.05) influenced by stressor treatment. Water-holding capacity of meat was not (P > 0.05) influenced by stressor treatment. Older goats had lower (P < 0.01) L* values and greater (P < 0.01) a* and chroma values than the younger goats. The a* and chroma values of loin cuts from young goat carcasses were lower in the TS than NS treatment groups, but this effect was absent in the old goat carcasses (stressor treatment x age, P < 0.05). Cooking loss percentages and shear force values for loin chops aged for 7 d were not (P < 0.05) affected by stressor treatment; however, old goats produced tougher (P < 0.01) loin chops than young goats. These results indicate that short-term preslaughter transport can cause noticeable changes in stress responses and muscle metabolism in goats.

Age Factors↗

Influence of dietary vitamin E supplementation on "heavy" pig carcass characteristics, meat quality, and vitamin E status.

Crossbred "heavy" pigs (average weight 120 kg, slaughter weight above 160 kg) were supplemented with all-rac-alpha-tocopheryl acetate during the last 60 d of late finishing at doses of 25 (control), 50, 100, 200, or 300 mg/kg of diet. At the end of this period, the pigs were slaughtered. Carcass characteristics and the meat quality of pork chops from longissimus muscle (LM) at the last lumbar vertebra were evaluated on eight barrows from each dosage group. Alpha-tocopherol levels were determined in plasma during supplementation and in LM muscle after slaughter. Thiobarbituric acid reactive substances (TBARS) and drip loss were also evaluated in meat. Plasma alpha-tocopherol levels increased (P < .005) during supplementation in treated animals compared to controls, with a peak at 40 d. Alpha-tocopherol levels were higher (P < .05) in LM from pigs treated with 300 mg/kg than in controls (8.4 vs 5.6 microg/g). Dressing percentages correlated (P < .05) with the ratio of plasma alpha-tocopherol levels to the sum of cholesterol and triglycerides. Inhibition of TBARS during storage was related (P < .005) to vitamin E supplementation level, but drip losses in chops were not related to supplementation levels. We concluded that dietary vitamin E supplementation to heavy pigs during the last 60 d of finishing improves dressing percentage, reduces lipid oxidation, and increases the alpha-tocopherol concentration of tissues.

Animal Feed↗

Effects of yeast (Saccharomyces cerevisiae) cell components on growth performance, meat quality, and ileal mucosa development of broiler chicks.

An experiment was conducted with 240, 1-d-old, male broilers to investigate the effects of Saccharomyces cerevisiae (SC) cell components on the growth performance, meat quality, and ileal mucosa development. There were 4 dietary treatments, each consisting of 6 replicates. Whole yeast (WY), SC extract (YE), and SC cell wall (CW) were added at 0.5, 0.3, and 0.3%, respectively, to the control starter and finisher diets. From 0 to 3 wk of age, a lower feed/gain ratio (P < or = 0.05) was observed with CW, whereas the WY-fed birds at 4 to 5 wk of age showed a lower feed/gain ratio compared with the control. From 0 to 5 wk of age, WY and CW gave higher BW gains than did the control. The shear force of raw drumstick decreased in the WY treatment relative to the control, and YE and CW treatments were intermediate. The shear forces in cooked breast and drumstick in treatments WY and YE decreased when compared with the control. The amount of 2-thiobarbituric acid-reactive substances (TBARS) in the breast meats of WY, YE, and CW were lower than the control at 10 d of incubation. In raw drumstick meats, TBARS values were lower in treatments WY and YE than that of the control at 6 and 10 d of incubation. At 10 d of incubation, skins from YE and CW treatments had lower TBARS values than did the control. Villus height was greater in WY and CW compared with those in control and YE. No differences were found in crypt depth among the 4 treatments. The villus height/ crypt depth ratios in WY and CW were greater than those of the control and YE. It could be concluded that dietary yeast components, such as WY or CW supplementation improved growth performance. Meat tenderness could be improved by the WY or YE. Both YE and CW had oxidation-reducing effects. Yeast cell wall may improve ileal villus development.

Animals↗

Influence of environmental temperature on growth, muscle and adipose tissue metabolism, and meat quality in swine.

An experiment involving 32 individually housed, castrated male pigs was conducted to determine the effects of environmental temperature (12 degrees C = T12 or 28 degrees C = T28) on the performance, carcass characteristics, muscle and adipose tissue metabolism, and meat quality of pigs fed to achieve equal rates of weight gain between 8 and 92 kg live weight. The T12 pigs had less muscle (P less than .01) and more subcutaneous fat (P less than .01) in the ham than did T28 animals. Thyroids and adrenals were heavier (P less than .01) in T12 than in T28 pigs. Percentage of type I muscle fibers was higher (P less than .01) and fiber cross-sectional areas smaller (P less than .01) in semispinalis muscle (SS) of T12 pigs, whereas no effect of temperature was noticed in longissimus muscle (LD). Cold exposure induced a larger increase in oxidative metabolism in SS (+30 to 32%, P less than .001) than in LD (+14 to 17%, P less than .10) and an enhanced glycolytic metabolism in LD (P less than .05). Lipid concentration was higher in SS of T12 than in that of T28 pigs. Lipogenic enzyme activities and unsaturation of backfat were higher in T12 than in T28 pigs, whereas no effect of temperature was noticed in leaf fat. Cold treatment resulted in a faster postmortem pH decline (P less than .01), higher glycolytic potential (P less than .01), and lower ultimate pH (P less than .01) in LD. The results indicate that 12 degrees C vs 28 degrees C induced detrimental effects on growth, ham composition, and muscle and adipose tissue quality.

Adenosine Triphosphatases↗