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PubMed2005

Repeated handling of pigs during rearing. II. Effect of reactivity to humans on aggression during mixing and on meat quality.

The present study was designed to determine whether reactivity toward humans can be used to predict a pig's reactivity to the slaughter procedure as measured by postmortem muscle metabolism. Forty-two pigs were group-reared in six pens with straw-bedding. Pigs received regular positive (HI) or mildly negative (RC) handling training in a separate pen for 40 d before slaughter. Control pigs remained in their home pens throughout rearing. Pigs were slaughtered at a commercial packing plant, and half of each treatment group (HI, RC, or controls) was accompanied by the handler throughout mixing and transportation, as well as a portion of the lairage time and introduction to the holding pens situated before the slaughter room, whereas the other half was not accompanied by the handler. Muscle pH and temperature, objective color (L*, a*, and b* values), and drip loss were measured on the LM, biceps femoris, semimembranosus, and adductor femoris. Prior handling experience did not in itself influence ultimate meat quality (P > 0.37); however, the presence of the negative handler (RC pigs) at slaughter accelerated (P < 0.06) preslaughter glycogen breakdown in the LM. Fighting behavior during mixing explained between 13 and 32% of the variability of lightness (L* values) of the LM, biceps femoris, and semimembranosus. Visual contact with the handler at the start of the handling training and number of fights initiated explained between 31 and 42% of the variability in ultimate muscle pH. Latency to approaching the handler during human exposure tests explained 20% of the variability in initial muscle temperature of two muscles. Fighting behavior during mixing could be partly predicted from fighting during a food competition test conducted at the start of the rearing period. Results indicate that reactivity to humans and the tendency to fight determined, in part, meat quality in pigs of similar genetic and rearing backgrounds. These behavioral characteristics were, to some extent, determined early in life. Handling experience modified behavior toward the handler but correlations between behavioral characteristics and meat quality were not influenced by prior handling experience.

Aggression↗
PubMed2002

Analysis of associations of PIT1 genotypes with growth, meat quality and carcass composition traits in pigs.

PIT1 was chosen as a candidate gene to investigate its associations with growth, meat quality and carcass composition traits in the pig. PIT1 is known as the pituitary-specific activator of the growth hormone in several mammals. Furthermore, PIT1 is a positive regulatory factor of prolactin and thyroid-stimulating hormone beta. PIT1 is a member of the POU-domain family of genes and is located on porcine chromosome 13. Two informative three-generation families of the University of Hohenheim were used for the presented investigations. The families were based on crosses of the European Wild boar (W) x Pietrain (P) and Meishan (M) x Pietrain (P). Each family included 310 F(2) animals. A RsaI (PCR) RFLP described by Yu et al. (1994) was used for genotyping the animals. Altogether over 50 parameters of growth, meat quality, carcass composition and stress susceptibility were evaluated concerning their associations with RsaI PCR-RFLP. The statistical model of association analyses was used including fixed effects of sex, family, PIT1 genotypes and covariate age at slaughter. Taking the significance level of p < 0.05 as the basis, fourteen traits of growth and carcass composition were associated with PIT1 genotypes in family W x P. Results from this study suggest that there are contributions of PIT1 gene to variations in the analysed performance traits in pigs. The influence of PIT1 genotypes could not be confirmed under the supposition of a genome-wide test limit.

Animals↗
PubMed2005

Effect of endophyte type on carcass traits, meat quality, and fatty acid composition of beef cattle grazing tall fescue.

Fourteen Hereford steers were used to compare carcass traits, meat quality, and fatty acid composition of beef from cattle grazing tall fescue infected with either wild-type (E+; n = 6) or novel, nil ergot alkaloid (AR542; n = 8) endophyte for 209 d. Average daily gain, live weight, and HCW were greater (P < 0.05) for AR542 cattle than for E+. No differences in LM color or pH were observed between AR542 and E+. Steaks from E+ cattle tended (P = 0.10) to have higher L* and b* than those from AR542 cattle at 0 d of display. Ground beef from E+ cattle also had higher (P < 0.05) L* than AR542 cattle, with no differences in a* or b* at 0 d of display. Color changes during display did not differ for both steaks and ground beef from E+ and AR542. Lipid oxidation levels increased (P < 0.05) during simulated retail display, but they did not differ between endophyte treatments. Adipose tissues from E+ cattle had a higher (P < 0.05) percentage of SFA, and a lower (P < 0.05) percentage of MUFA than adipose from AR542 cattle. Ground beef and i.m. fat had higher (P < 0.05) concentrations of SFA, MUFA, and cis-9, trans-11 isomer of conjugated linoleic acid, and lower (P < 0.05) concentrations of PUFA and PUFA:SFA ratio than s.c. fat. The n-6:n-3 fatty acid ratio did not differ among fat depots. Ergot-alkaloids were detected in s.c. adipose tissues, and alkaloid concentration was greater (P < 0.05) for E+ than AR542. Warner-Bratzler shear force values did not differ between endophyte types, but it decreased (P < 0.01) across the postmortem aging period. Conversely, sensory panel evaluation detected greater (P < 0.01) chewiness and lower (P < 0.05) juiciness for AR542 than for E+ steaks aged for 14 d. Although grazing cattle on tall fescue pastures infected with nil ergot alkaloid endophyte improved cattle performance, these results suggest that endophyte type has minor effects on carcass traits and meat quality of pasture-fed beef. Moreover, finishing cattle on tall fescue pastures showed the potential to enhance the fatty acid profile of beef from a human health perspective. Alkaloid concentration was greater (P < 0.05) in s.c. fat from E+ than AR542 (2.81 vs. 0.92 ppb; fresh-tissue basis). This is the first published report demonstrating the presence of alkaloids in beef tissues.

Adipose Tissue↗
PubMed1997

Carcase and meat quality in broilers either killed with a gas mixture or stunned with an electric current under commercial processing conditions.

1. Carcase and meat quality were evaluated under commercial conditions in 400 broilers either killed with a mixture of 30% carbon dioxide and 60% argon in air or stunned with a 50 Hz AC with clipped sine wave. 2. Compared with electrical stunning, killing broilers with the gas mixture eliminated or substantially reduced the prevalence of carcase and meat quality defects. 3. The results also showed that killing broilers with a mixture of 30% carbon dioxide and 60% argon would enable filleting (deboning) to be performed at 4 h post mortem without adversely affecting the cook loss or texture of breast meat.

Abattoirs↗
PubMed2005

[Effects of FUT1 gene on meat quality and carcass traits in swine].

A total of 139 hybrid finishing pigs from Large White x Meishan were slaughtered at about 88kg body weight. Fourteen meat quality traits and 8 carcass traits were assayed for each pig. FUT1 gene was scored by PCR-RFLP. The values of meat pH and meat color for AA genotype pig were higher than those of AG genotype pig (P<0.05). Water holding capacity (WHC) of AA genotype pig was higher than that of AG genotype pig(91.02% VS 86.70%, P<0.05). Backfat at 6-7 vertebra (BV) and backfat at vertebra-lumbar (BVL) of AA genotype pig were lower than those of AG genotype pig 4.26 mm and 3.96 mm respectively (P<0.05). Meat factor of AA genotype pig was higher than that of AG genotype pig 3.31% (53.46% VS 50.15%, P<0.05). These results indicated that FUT1 gene had good genetic effects on pig meat quality and carcass traits.

Adipose Tissue↗
PubMed2026

Elucidating the evolution of meat quality, water distribution, microstructure, and protein structure during sous-vide and micro-pressure cooking.

This study investigated the evolution of eating quality (colour, texture and volatile flavour compounds), water status, microstructure and protein structure of pork meat under different cooking methods. The methods analysed included traditional cooking (TC: 10, 20, 30 and 40&#xa0;min, 100&#xa0;&#xb0;C), sous-vide cooking (SV: 1, 2, 3 and 4&#xa0;h, 60&#xa0;&#xb0;C) and micro-pressure cooking (MC: 10, 20, 30 and 40&#xa0;min, 120&#xa0;&#xb0;C). Across the three cooking processes, as cooking time increased, cooking loss, lightness, yellowness, P23, &#x3b2;-sheet, random coil and surface hydrophobicity of the meat samples increased. By contrast, redness, P22, hydrogen proton density, esters content, &#x3b1;-helix, &#x3b2;-turn and sulfhydryl group content decreased. Moreover, the Warner-Bratzler shear force (WBSF), adhesiveness, hardness, springiness, gumminess, chewiness, alcohols, aldehydes, ketones and fluorescence intensity of the meat samples, initially increased and then decreased as cooking progressed. SV resulted in higher water-holding capacity (WHC), improved redness and increased alcohol and ester levels, whereas MC produced softer meat and greater water mobility. Furthermore, MC enhanced the degree of microstructural damage and protein structural unfolding in the meat. MC requires less time to achieve textures and flavours similar to those obtained using the TC and SV methods. Thus, MC is an efficient cooking method for the catering industry to obtain desired meat quality rapidly.

Cooking↗
PubMed1997

A comparison of high current and low voltage electrical stunning systems on broiler breast rigor development and meat quality.

Experiments were conducted to compare the effects of a high current (HC) stunning system to a low voltage (LV) stunning system on broiler carcass and meat quality. A total of 360 broiler chickens were individually stunned using either 125 mA, 50 Hz, constant AC for 5 s (HC) or using 10.5 V, 500 Hz pulsed DC for 10 s (LV). Birds were individually weighted, killed by conventional neck cut, bled for 150 s, and reweighed to determine blood loss. Breast fillets (Pectoralis major) were removed from the carcass immediately after picking (0 h) or after aging for 24 h in a static ice-water slush. Breast muscle pH was determined at both 0 and 24 h. Raw breast meat color (CIELAB) and cooked breast meat Allo-Kramer shear values were determined on samples held at 2 C for 48 h. The LV stunning treatment significantly increased (P < 0.05) blood loss (4.0 vs 3.7%) and significantly reduced initial muscle pH (6.47 vs 6.67) when compared to the HC stunning treatment. There were no significant differences between the stunning systems for 24 h pH, raw breast color, and Allo-Kramer shear. High current stunning reduced initial blood loss and delayed early rigor development compared to the LV treatment, but appeared to have little effect on final meat quality.

Animals↗
PubMed1977

[Studies on the muscle meat quality of swine. 3. Significance of meat temperature with special reference to transport forms].

Pork temperatures of M. longissimus were recorded from 1,010 pigs transported in different ways 45 minutes post mortem, with the following results having been obtained: 1. Following conventional transport, pork values were significantly higher than they had been following container transport (37.8 degrees C or 36.8 degrees C). 2. Pork values were clearly influenced by driving into the slaughterhouse, high ambient temperatures, and additional environment-borne effects prevalent on the day of slaughter. Genetic configurations, transport, and rest periods, on the other hand, proved of minor importance. 3. Pork temperature was found to be unsuitable for any characterisation of pork quality, since only unimportant correlations existed with juice retention and colour brightness, and secured relationships were found to exist merely with the pH-value. 4. Changes in rectal temperature and respiratory frequency following conventional transport were slightly stronger than those following container transport. Both of them were normalised after one or two hours and are well suitable for an assessment of preceding transport stress.

Abattoirs↗
PubMed1998

Effects of regular moving and handling on the behavioral and physiological responses of pigs to preslaughter treatment and consequences for subsequent meat quality.

The effects of regular moving and handling during the finishing period on behavioral and physiological responses of pigs during preslaughter treatment and consequences for meat quality were studied. From the age of 10 wk onward, 144 pigs were housed in groups of four (two gilts and two castrates) and subjected to one of the following treatments. The Environment treatment allowed pigs to move freely for 8 min outside their home pen. Then the pigs were transported in a box for 2 min, and after which they were returned to their home pen. In the Handling treatment, an experimenter remained for 3 min in the pen, and whenever a pig made contact, it was gently stroked. The experimenter then walked for an additional 1 min, without attempting to pat or stroke any pigs but subsequently held each pig in a tight grip for about 5 s. This entire procedure was then repeated. A Control treatment was also included, in which the pigs were subjected to no treatment. The Environment and Handling treatments were applied twice a week at the age of 15, 17, 19, 21, and 23 wk. At 25 wk of age, pigs were transported to the abattoir. They were held unmixed in the truck and in lairage and were manually stunned. The stockmen needed significantly less time to move Environment pigs out of their pen and into the transport box. There were no differences between treatments in salivary cortisol concentrations before or after transport. Environment and Handling pigs had paler meat than Control pigs. Glycogen content at 1 h after death and water-holding capacity were lower in Environment pigs than in Control pigs, but this did not lead to a higher incidence of PSE meat. We conclude that the pigs that had experience with leaving their home pen and some of the transport conditions were much easier to handle at loading. Pigs that are easier to move are less likely to be subjected to rough handling, which implies improved welfare, and the workload for personnel at the time of marketing is reduced. Differences in meat quality due to treatment were slight.

Abattoirs↗
PubMed2006

Results of a whole-genome quantitative trait locus scan for growth, carcass composition and meat quality in a porcine four-way cross.

A whole-genome quantitative trait locus (QTL) scan for 31 phenotypes related to growth, carcass composition and meat quality was conducted using 1187 progeny of a commercial four-way cross. Animals were genotyped for 198 microsatellite markers that spanned the entire porcine genome. QTL analysis was conducted to extract information from paternal and maternal meioses separately using a rank-based nonparametric approach for half-sib designs. Nine QTL exceeded genome-wide significance: one QTL affecting growth (average daily gain on SSC1), two QTL influencing carcass composition (fatness on SSC3 and muscle mass on SSC15) and six QTL influencing meat quality (tenderness on SSC4 and SSC14; colour on SSC5, SSC6 and SSCX; and conductivity on SSC16). All but one of these coincided with previously reported QTL. In addition, we present evidence for 78 suggestive QTL with a combined false discovery rate of 40%.

Animals↗
PubMed2005

Carcass composition, bone mechanical properties, and meat quality traits in relation to growth rate in rabbits.

The objective of this study was to characterize correlated responses in carcass composition, bone mechanical properties, and meat quality indicators to divergent selection for growth rate. Rabbits from low (LOW) or high (HIGH) lines divergently selected over five generations on 63-d BW and a control group (CONT) were used. Rabbits were slaughtered at an average BW of 2,306 +/- 65 g, corresponding to 63, 58, or 52 d of age in LOW (n = 41), CONT (n = 43), and HIGH (n = 44) groups, respectively. Postweaning ADG and G:F increased (P < 0.001) in the order LOW < CONT < HIGH groups. The lengths of the tibia and femur in rabbit legs decreased (P < 0.001) with increasing growth rate. Tibia and femur bone intrinsic stiffness, as assessed by a three-point flexure test, followed the order (P < 0.001) of HIGH < CONT < LOW groups. At the same BW, HIGH rabbits and CONT rabbits showed many similarities for dressing percent, carcass composition, and color and chemical composition of muscles or meat parts. In contrast, carcass yield and the relative proportion of hind part were 3% greater (P < 0.01) in LOW rabbits than in CONT and HIGH rabbits. The meat-to-bone ratio in the hind leg was 11% greater (P < 0.001) in the LOW group compared with the CONT and HIGH groups. Yellow color index and moisture content in LM, a fast-twitch glycolytic muscle, were lower (P < 0.05) in LOW rabbits than in HIGH rabbits, but ultimate pH, WHC, and cooking loss did not differ between the two growth-selected lines. Ultimate pH in semitendinosus, a mixed slow- and fast-twitch oxidoglycolytic muscle, was less (P < 0.001) in HIGH rabbits than in CONT and LOW rabbits. However, lactate dehydrogenase and isocitrate dehydrogenase activities in this muscle (n = 21 per group), assessed at the time of slaughter as markers of glycolytic and oxidative capacities, respectively, did not differ among groups. Growth rate did not modify mean cross-sectional area and type frequency of myofibers in semitendinosus muscle. Finally, Warner-Bratzler shear force and total energy needed to achieve rupture did not differ among groups in semitendinosus muscle (n = 21 per group), whereas they were the least (P < 0.001) in LM (n = 128) from HIGH rabbits. Results from this study indicate that improvement of growth rate by selection has little effect in rabbit carcass and meat quality traits.

Animals↗
PubMed1999

Evaluation of the ovine callipyge locus: III. genotypic effects on meat quality traits.

A resource flock of 362 F2 lambs provided phenotypic and genotypic data to estimate effects of callipyge (CLPG) genotypes (NN, NC, CN, and CC) on meat quality traits. The mutant allele is represented as C, the normal allele(s) as N, and the paternal allele of a genotype is given first. Lambs of each genotype born in 1994 and 1995 were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age. Warner-Bratzler shear force and subjective evaluation of marbling were collected during both years from longissimus. Calpastatin activity was measured on longissimus from the 1994 group, and ELISA quantification of calpastatin protein was obtained from the 1995 group. Significant additive and paternal polar overdominance effects on meat quality traits were detected. This is in contrast to previous research that detected only polar overdominance effects on slaughter and carcass traits in this population. The magnitude of genotypic effects on shear force differed significantly between years; however, additive (P < .01), paternal polar overdominance (P < .001), and maternal dominance (P < .01) effects adjusted for variation in carcass weight were detected within each year. Shear force data adjusted to the mean slaughter age or carcass weight indicated that the means and variances of CN and CC genotypes were greater than values of NC and NN. Shear force values were greatest for CN and were intermediate for CC. The difference in shear force (adjusted for variation in slaughter age) between homozygous genotypes (additive effect) was supported by calpastatin activity data with 2-df F-tests of 3.66 (P < .05) and 11.84 (P < .001) at d 0 and 7 postmortem, respectively. Corresponding values for the paternal polar overdominance effects on calpastatin activity were 53.80 (P < .001) and 87.43 (P < .001). Calpastatin ELISA data (d 0, adjusted for slaughter age) exhibited a paternal polar overdominance effect exclusively with a 2-df F-test of 57.63 (P < .001). Additive and paternal polar overdominance effects on marbling adjusted for slaughter age had F-tests of 6.41 (P < .01) and 93.29 (P < .001), respectively. Consequences of increased longissimus shear force must be addressed if the advantages of CN lambs for dressing percentage and carcass composition are to be realized. Further research is needed to establish whether selection targeted at changing the background genome can mitigate the negative effects of the C allele on meat tenderness.

Animals↗
PubMed2005

Vitamin E supplementation, cereal feed type and consumer sensory perceptions of poultry meat quality.

Lipid oxidation leads to meat spoilage and has been reported to cause adverse changes in the flavour and texture of poultry meat. Vitamin E has been found to be effective in delaying lipid oxidation. The aim of this study was to determine whether the vitamin E supplementation of chicken feed influences the consumers' perception of the quality of chicken meat under normal display and storage conditions. Untrained consumers (n 32) evaluated cooked breast meat from chickens (both corn fed and wheat fed) supplemented with 75,250 or 500 mg/kg vitamin E and after storage at 4 degrees C for 4 and 7 d. Factorial analysis found an interaction between vitamin E treatment and storage day upon the perceived juiciness (P=0.023) and tenderness (P=0.041) of the chicken meat. Perceptions of quality relative to vitamin E level were more evident on day 4 than day 7. When the two cereal types were compared, the time-related sub-group effects were observed only in meat from corn-fed chickens supplemented with either 75 or 250 mg/kg, which was perceived to be juicier (P=0.018) and more tender (P=0.020) than that supplemented at the 500 mg/kg level. These results imply that the two lower concentrations of vitamin E have some advantages over 500 mg/kg, but for optimal consumer acceptance of corn-fed chicken meat, we suggest that 250 mg/kg vitamin E should be added to corn-fed poultry feed. There was no evidence to suggest any advantages in changing the current amount of vitamin E (75 mg/kg) used to rear wheat-fed birds.

Adult↗
PubMed2001

Acute heat stress-induced alterations in blood acid-base status and skeletal muscle membrane integrity in broiler chickens at two ages: implications for meat quality.

The effects of acute heat stress (AHS) on indices of respiratory thermoregulation and skeletal muscle damage (myopathy) were examined in broiler chickens at two ages (35 and 63 d of age); the relationships of these responses with changes in meat quality were assessed. Exposure to AHS significantly increased deep-body temperatures, panting-induced acid/base disturbances, and plasma creatine kinase (CK) activities, reflecting heat stress-induced myopathy (HSIM). The extent of the hyperthermia and disturbances in acid/base status and myopathy was significantly (P < 0.05) higher in the older birds. Consistent with AHS-induced alterations in thermoregulatory indices and muscle membrane integrity were changes in breast muscle glycolytic metabolism as indicated by lower muscle pH immediately postslaughter (pHi), increased water loss, and increased incidence of breast muscle hemorrhages. Values of pHi were lower and hemorrhage scores greater in the AHS birds at 63 d; drip losses were significantly higher in the 35-d-old birds. Exposure to AHS did not affect breast meat eating quality, although overall reductions in flavor attributes were observed in the older birds. We concluded that exposure to AHS induced disturbances in blood acid/base status and had a detrimental effect upon skeletal muscle membrane integrity. Muscle from broilers exhibited an increased sensitivity to AHS exposure with age. Alterations in antemortem blood acid/base status and muscle membrane integrity induced by AHS were associated (though not necessarily causally) with adverse effects upon breast meat quality. It is recommended that preslaughter exposure of broiler chickens to AHS should be avoided in order to reduce alterations in muscle metabolism and membrane integrity and undesirable meat characteristics.

Acid-Base Equilibrium↗
PubMed2003

Meat quality and transport stress of cattle.

This study evaluated the effect of transport time up to 14 hours and the effects of vehicle design on animal welfare, stress and meat quality. 18 transports (six short, medium and long) with a total of 486 animals (118 sample animals, heifers and bulls) were carried out on commercial vehicles in summer 2000 and winter 2001. Animal welfare and stress were evaluated by blood serum parameters, heart rate monitoring, behaviour recording and occurrence of carcass bruising. Meat quality was evaluated by post mortem muscle glycogen content, pH value, temperature, drip loss, colour and tenderness measurements. Heifers had lower heart rates than young bulls during loading (95 vs 114 beats per minute, bpm), whereas during transport, both had an average heart rate of 100 bpm, furthermore during unloading, heifers had higher heart rates than bulls (109 vs 100 bpm). Blood sampling during unloading could have marginally increased heart rates during the unloading procedure. Studied cattle had lower heart rates during medium and long distance transports compared with short transports. Monitoring of animal behaviour during transport showed that the former settled down faster than the latter. Single- and two-animal pens in medium and long distance vehicles prevented nervous and stressful movements of cattle, which were more prominent in large pens of short distance lorry. Present results suggest that larger pens of three or four animals could increase cattle stress during transport. Moreover during unloading, cattle loaded in single- or two-animals pens had significantly lower blood cortisol content than those loaded in larger groups of three or four animals (P < 0.01). The amount of severe carcass bruising was highest in animals transported over short times and loaded into groups of four cattle. Severe damages occurred most often on perianal and hipbone area of the carcass surface. Present results showed that muscle glycogen level was highest after long transport. These animals were fed more regularly from the last feeding up to stunning than medium or short distance animals. Animals in single-pens had the highest muscle glycogen level. Transport distance or number of animals in one pen had a minor effect on muscle pH values or temperatures during 24 hours post mortem (pm). Drip loss of the M. longissimus dorsi (LD) was highest after long transport, but animal number in one pen had no effect on drip loss. Colour of the LD muscle was independent on transport conditions. Light colour of three animal groups resulted from high amounts of heifers, which had lighter colour than bulls. All meat samples were quite tender. However, heifers had significantly tender meat than young bulls (P < 0.001). Higher amounts of heifers had the most tender meat after short transports. Mean DFD (dark, firm, dry) meat occurrence was 2.1% in this project, DFD frequency was lowest after short, then after long and highest after medium distance transports. Because of not evenly distributed numbers of bulls (low) and heifers (high) it was difficult to compare short and long distance transport effects.

Animal Welfare↗
PubMed2005

Comparison of bruises and mortality, stress parameters, and meat quality in manually and mechanically caught broilers.

A field trial was conducted to compare manual catching of broilers with a mechanical catching method. Both methods were compared with respect to the incidence of bruises and dead on arrival, stress parameters, and meat quality. Also the dynamics of corticosterone, glucose, and lactate were investigated on the day broilers were killed. The broilers originated from 8 commercial broiler farms; visits were made on the day of catching during spring and autumn of 2001. Broilers of one house were caught manually, and those of the second house were caught mechanically. Plasma samples were taken before catching started, 30 min after the start of catching, 30 min before the end of catching, and at exsanguination of broilers from the first- and last-loaded transport vehicles. Postmortem measurements of pH, temperature, and water-holding capacity were made. Mechanical catching was associated with higher DOA percentages than manual catching in spring, although the difference was not significant in autumn. Catching method did not influence the percentage of bruises or meat quality. Moreover, corticosterone levels indicated that both methods induced the same amount of stress. The dynamics of corticosterone, glucose, and lactate levels showed a similar pattern. Plasma levels increased at the start of catching, and they further increased during transport, shackling, and stunning. However during catching itself, no large changes were observed. Our findings indicated that attempts to reduce stress in broilers during the last day of life could better be focused on factors other than catching.

Abattoirs↗
PubMed2001

Muscle glycogen stores and meat quality as affected by strategic finishing feeding of slaughter pigs.

The aim of the present study was to investigate whether muscle glycogen stores in slaughter pigs could be decreased through strategic finishing feeding before slaughter. Moreover, preliminary meat quality traits were measured to see whether such a regulation of muscle glycogen stores affected ultimate pH, color, and tenderness in the meat. The strategic finishing feeding was carried out the last 3 wk prior to slaughter. Seven experimental groups with eight animals per group were fed diets low in digestible carbohydrates. A control group with four animals was fed a traditional grower-finishing diet. The muscle glycogen stores were reduced in longissimus muscle (LM) 11 to 26% at the time of slaughter in pigs that were fed the experimental diets compared with the control group. Meat quality measured as ultimate pH and color on LM muscle in half the pigs 24 h postmortem showed that ultimate pH in LM was not affected by the reduction in glycogen stores in the muscles from pigs fed any of the experimental diets. However, the meat from pigs fed the experimental diets was darker than the meat from pigs that were fed the control diet with two of the experimental diets, resulting in significantly lower L* values. Activities of key enzymes in the glycolytic pathway, glycogen phoshorylase a and b, phosphofructokinase, and the fatty acid oxidative pathway, beta-hydrozyacyl-CoA-dehydrogenase, were not affected by the strategic feeding. In contrast, the activity of the proteolytic enzyme calpain as well as its inhibitor calpastatin was influenced by the strategic feeding. Lower activity of mu-calpain and greater activity of calpastatin in the muscle samples from the strategically fed pigs indicate a lesser muscle protein degradation in the muscles compared with muscles of control animals. The present study showed that the muscle glycogen stores in slaughter pigs can be reduced at the time of slaughter through strategic finishing feeding with diets low in digestible carbohydrate without compromising growth rate.

3-Hydroxyacyl CoA Dehydrogenases↗