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[Evaluation of the meat quality of game].

The carcasses of 140 roe deer, 129 wild boars, 81 red deer and 55 fallow deer were examined to determine meat quality with respect to the influence of typical hunting situations. After hunting, many carcasses had not been cooled, which significantly influenced meat-quality parameters. The pH-value, detected electrochemically, gave the most reliable results out of all the meat-quality parameters investigated. Determination of the pH-value with regard to the pH indexes ascertained for different points of measurement and types of game is helpful in properly judging the substantial quality of venison. Determination of electrical conductivity and water-holding capacity (Q) can be helpful in judging meat quality. The value of residual-blood content in judging substantial venison quality is, however, doubtful. The measurement of rapid glycolysis and the evaluation of rigor mortis are not appropriate for determining the substantial quality of venison.

Animals↗

Meat quality traits were unaffected by a quantitative trait locus affecting leg composition traits in Texel sheep.

A QTL affecting leg muscle and fat traits has been identified within the New Zealand Texel population. The QTL maps to a region on OAR 2 with a two-marker haplotype test established at markers BULGE20 and BM81124. These markers encompass the likely position of Growth Differentiation Factor 8 (GDF8). The pleiotropic effects of this QTL on meat quality traits are tested. Objective measures of meat quality including pH, color (L*, a*, and b*), and tenderness (as assessed by Warner-Bratzler shear force measurements) were assessed on longissimus and semi-membranosus muscles of 540 progeny from six Texel sires. Four of these sires were subsequently identified as segregating for leg muscle and fat traits. For these segregating sires, comparison of progeny that had inherited the favorable haplotype from their sire with those that had received the alternate haplotype revealed no significant differences in the meat quality traits assessed. This finding suggests that the muscling QTL does not have pleiotropic effects on meat quality. A general scan for meat quality QTL was carried out using genotype data for eight markers from FCB128 to RM356 flanking 122cM of OAR 2 using Haley-Knott regression. This analysis revealed two QTL for a single sire. A QTL detected in the region of Marker INRA40 for color L* mapped to a site close to the muscling QTL, but there was evidence to suggest it is at a distinct locus. The QTL in the region of Marker RM356 might map distal to Marker RM356, as no peak was observed. This QTL, which seems to affect pH, color a*, color b*, and Warner-Bratzler shear measurements, requires further characterization.

Animals↗

[The significance of meat quality in marketing].

Food quality in general and meat quality in particular are not only evaluated by means of objective quality traits but the entire production process is gaining more attention by the modern consumer. Due to this development quality programs were developed to define the majority of the processes in all production and marketing steps which are again linked by contracts. Not all of these items are quality relevant, but are concessions to ethic principles (animal welfare etc.). This is demonstrated by the example of Scharrel-pork production. The price differentiation at the pork market is still influenced predominantly by quantitative carcass traits. On the European market quality programs still are of minor significance. Premiums which are paid for high quality standards are more or less compensated by higher production costs and lower lean meat percentages, which must be expected in stress susceptible strains. The high efforts to establish quality programs, however, help to improve the quality level in general, and secure the market shares for local producers.

Abattoirs↗

Associations between gut microbiota on carcass traits and meat quality in Neijiang pigs, Yorkshire pigs, and their hybrids.

This study was designed as an exploratory analysis to compare carcass performance, meat quality traits, and gut microbiota of Neijiang pigs (NN), Yorkshire pigs (YY), and Yorkshire &#xd7; Neijiang hybrid pigs (YN), with the goal of generating testable hypotheses regarding potential links between gut microbial composition and production phenotypes. Compared with NN pigs, YN hybrids exhibited improved carcass performance while inheriting the favorable meat quality characteristics of Neijiang pigs. The results of 16S rRNA sequencing analysis showed that the relative abundance of the microbiota was similar to that of NN pigs. LDA effect size (LEfSe) results showed that Streptococcus, Treponema, probable_genus_10 and Fibrobacter were the differentially enriched taxa in YN pigs (p < 0.05). Correlation analysis was performed on carcass, meat quality and intestinal microbiota screened out by LEfSe. The results showed that Akkermansia tended to positively associate with body length and oblique length in YN pigs; Dialister correlated positively with dressing rate and pH45min; Treponema showed positive trends with a*45min and a*24h (p < 0.05). Finally, the correlation network model preliminarily mapped associations among production traits, gut microbiota, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways for exploratory screening. Nine core microbial taxa exhibited close correlations with phenotypic indicators, which implied that these microbes might modulate metabolic pathways to shape pig performance. Overall, hybrids inherited superior parental carcass and meat quality but harbored unique gut microbial communities relative to purebreds-these preliminary correlative observations generate new hypotheses that gut microbiota may contribute to heterosis-associated phenotypic advantages, which require further targeted validation.

Animals↗

Microbial sensor system for nondestructive evaluation of fish meat quality.

A microbial sensor system consisting of the bacterium (Alteromonas putrefaciens) immobilized within membranes, a flow cell, an oxygen electrode, peristaltic pumps, a buffer tank, a thermostatically controlled bath and a recorder, was constructed for the nondestructive quality evaluation of bluefin tuna. The chemical compounds on fish meat surfaces which are the indicators of fish meat quality were rapidly determined by using the proposed sensor system. Fish meat quality was determined from the rate of current decrease of the sensor. Good correlations were obtained between fish meat quality and sensor response. One assay could be completed within one minute.

Animals↗

Variation of chicken technological meat quality in relation to genotype and preslaughter stress conditions.

The present study was aimed at estimating the genetic variability between lines of breast and thigh meat quality (pH decline, color, drip loss, and curing-cooking yield) by comparing a slow-growing French label-type line (SGL) and a fast-growing standard line (FGL) of chickens exposed to different preslaughter stress conditions. The birds were slaughtered under optimal conditions or after exposure to 2 h of transport or acute-heat stress (2 h at 35 degrees C). Relationships between meat quality and stress sensitivity were investigated by measuring struggle during shackling and tonic immobility (TI) duration, 1 wk before slaughter, as an indicator of the basal level of fear of the birds. Although most of the meat quality indicators varied between the 2 lines, differences were muscle dependent. In concordance with a lower ultimate pH, curing-cooking yield of thigh meat was decreased for the FGL birds. In contrast, these birds had a higher curing-cooking yield and a lower drip loss of breast meat resulting from a less rapid pH decline in this muscle compared with SGL birds. Thigh meat characteristics were influenced by both preslaughter stresses, but no significant effects were detected for breast meat. The main effect of heat stress in thigh meat was a decrease of the ultimate pH and led to paler color and lower curing-cooking yield; opposite effects were obtained for transport. Breast meat was much more sensitive to physical activity of birds on the shackle line. Longer durations of wing flapping on the shackle line gave more rapid initial pH decline. Whatever the line, no relationship between TI duration and meat quality characteristics or activity was observed. The present study suggested that SGL birds could be at disadvantage due to more struggle during shackling and accelerated postmortem glycolysis, which is detrimental to the quality of breast meat.

Animals↗

The effect of selection for growth rate and slaughter age on carcass composition and meat quality traits in rabbits.

The effect of selection for growth rate on carcass and meat quality was assessed by comparing selected and control populations of rabbits measured at the same stage of maturity and slaughtered at 9 and 13 wk of age. Embryos belonging to Generation 7 were frozen, thawed, and implanted in does to produce the control group. The control group was formed from the offspring of the embryos belonging to the Generation 7. Selected animals belonging to Generation 18 (S) were compared with contemporary animals of the control group (C). Carcasses were dissected and measured according to World Rabbit Science Association recommended practices. When animals were compared at similar degrees of maturity, selection for growth rate did not produce a negative effect on carcass and meat quality. There was no increase in fat content of the carcass, and there was an improvement of the meat:bone ratio with selection, with a difference between C and S groups of -0.42. However, the carcasses of S animals have 1.45% lower water-holding capacity. Carcass quality changed markedly with animal age. Heavy rabbit carcasses had lower organ percents and a higher loin percent. Dissectible and i.m. fat content were higher in older rabbits, with older animals having 0.97 and 0.79% more dissectible and i.m. fat content, respectively. Meat quality traits improved with age of slaughter, although there was an increase in glycolytic metabolism. Results from this study indicate that selection for growth rate has little effect in carcass and meat quality when rabbits are measured at the same stage of maturity.

Age Factors↗

Recycled cafeteria food waste as a feed for swine: nutrient content digestibility, growth, and meat quality.

This project was undertaken to compare growth, meat quality, and diet digestibility when pigs were fed cafeteria food waste (FW) or a corn/soybean meal (CSM) diet. Cafeteria food waste (36 samples) fed in the growing and finishing experiment averaged 22.4% DM, 21.4% CP, 14.1% ADF, 27.2% ether extract, and 3.2% ash. The first experiment used 50 crossbred pigs randomly assigned to four diets. During the growing phase, pigs fed a CSM diet gained faster (P < .05) than pigs fed FW or FW plus energy supplements. However, the two groups fed FW plus energy supplements (at 25 or 50% of the intake of the CSM diet) gained faster (P < .05) than pigs fed FW alone (.61 and .65 kg/d, respectively, vs .46 kg/d). In the finishing phase, FW plus an energy supplement fed at 50% of the level of CSM intake resulted in gains that did not differ from those of pigs fed the CSM diet (.90 vs .99 kg/d; P > .05). A nutrient digestibility and nitrogen balance trial using eight growing barrows compared FW with the same CSM growing diet fed earlier. Dry matter digestibility was similar for the two diets (P > .05). However, CP digestibility was higher (P < .05) in the FW diet than in the CSM diet (88.2 vs 84.3%). Although the percentage of nitrogen retained was not different between FW and CSM diets (56.0 vs 55.2%; P > .05), the amount of nitrogen retained was greater for pigs fed the CSM diet (29.3 vs. 24.5 g/d; P < .05) because DMI was greater (1.7 vs 1.4 kg/d) for pigs fed CSM compared with FW. At the completion of the finishing experiment, six pigs were selected from both the CSM and FW diets and fed to finishing weight. The pigs were slaughtered, and the pork loins were removed for flavor and texture analysis. A consumer panel rated the meat quality from FW pigs as acceptable and overall flavor comparable to CSM pigs (P > .05). These results indicate that food waste has nutritive value and may be useful in swine diets.

Animal Feed↗

Meat quality evaluation of minimally aged broiler breast fillets from five commercial genetic strains.

A total of 1,040 birds from 5 common commercial genetic broiler strains were raised and processed to analyze the effect of strain and deboning time on meat quality. The birds were processed at either 6 or 7 wk of age in 4 replications each. Carcasses were deboned at either 2 or 4 h postmortem (PM; n = 52 birds per treatment). Carcass and breast weights were measured on each bird to calculate breast yield. Muscle pH was measured at time of deboning. Fillets deboned at 4 h PM were measured for length, width, and height to evaluate footprint analysis. At 24 h PM, fillets were weighed to calculate drip loss, and color (L*) was also measured. The fillets were then cooked to 76 degrees C, and cook loss was calculated. Fillets were then subjected to shear analysis using the Meullenet-Owens razor shear method where shear energy (N x mm) was calculated to evaluate tenderness. The strains in this study were chosen for differences in yield; therefore, as expected, breast yield was significantly different among strains. Variation in meat quality attributes existed among strains deboned at 2 h PM, but there was no consistent relationship between meat quality and breast yield. However, at 4 h PM, fewer differences among strains existed in meat quality characteristics (tenderness, water holding capacity, and pH). As expected, deboning at 2 h PM resulted in higher shear energy, higher muscle pH, and lower L* value compared with deboning at 4 h PM in all but one strain. However, water-holding capacity was not affected by deboning time at either age interval. Footprint analysis showed that most differences among strains were in heights measured at the fillet midpoint and caudal end. These results suggest that early deboning may affect meat quality of broiler strains differently, resulting in greater variation within the industry.

Aging↗

n-3 enrichment of chicken meat. 1. Use of very long-chain fatty acids in chicken diets and their influence on meat quality: fish oil.

We assessed the effect of a diet supplemented with fish oil (FO) on the performance, fatty acid (FA) composition, quality, and sensory traits of broiler meat. Diets enriched with 0, 2, or 4% FO plus tallow (T) up to 8% added fat (T1, T2, and T3, respectively) were given to the birds throughout a 38-d growth period. T3 was replaced by a mixture of FO, linseed oil (LO), and T (1, 3, and 4% respectively) for 1 wk (T4) or 2 wk (T5) before slaughter. Meat quality, taste, and FA profile were determined. Higher final weights were recorded for birds fed T3, although feed efficiency was not affected. Other performance or objective meat quality parameters did not show significant differences among treatments. High FO concentrations decreased the saturated and monoenoic FA contents in the thigh samples. The amount of polyunsaturated fatty acids (PUFA) increased when added to the diet (FO diets), mainly as long-chain n-3 FA [eicosapentaenoic fatty acid (EPA), docosapentaenoic fatty acid (DPA), and docosahexaenoic fatty acid (DHA)]. On the other hand, levels of total n-6 FA resulted in slight changes, mostly in linoleic acid (LA). By replacing the FO diet with the experimental mixture (T4, T5), the n-3 and n-6 FA contents increased, mainly in the form of linolenic acid and LA, respectively, only 1 wk later. After 1 wk of T4, the DHA levels in chicken decreased. Sensory panelists could not identify the meats from T4 and T5 as being different from the control diet (T1).

Animal Feed↗

Effect of dietary protein source and lysine:DE ratio on growth performance, meat quality, and body composition of growing-finishing pigs.

The effects of four protein sources (soybean meal, sunflower meal, pea, and fish meal as the main protein source) and three apparent ileally digestible Lys:DE ratios (0.50, 0.43, 0.36 and 0.42, 0.36, 0.30 g Lys/MJ DE for 30 to 60 kg BW and 60 to 105 kg BW, respectively) in pig diets on growing-finishing performance, and carcass and meat quality traits were investigated. Eight individually housed animals per treatment received the diets from 30 to 105 kg BW at a level of 3.0 times maintenance requirements of energy. The ileal digestibility of protein sources was determined in a previous digestibility experiment. Protein sources showed no differences in growth performance from 30 to 105 kg BW. From 30 to 60 kg BW soybean treatment had lowest performance. The protein sources had no effect on lean meat percentage, liver weight, or meat quality (intramuscular fat content, pH at 45 min and 24 h after slaughter, drip loss, and meat color measured 24 h and 4 d after slaughter). The experimental diets formulated on the basis of similar apparent ileal digestible lysine content resulted in similar body composition regardless of the protein source used (P > 0.05). Reducing the Lys:DE ratio from 0.50/0.43 to 0.36/0.30 (by about 28%) reduced BW gain by 119 g/d from 30 to 60 kg and by 151 g/d from 60 to 105 kg BW. The gain:feed ratio increased by 82 g/kg in the first phase and by 47 g/kg in the second phase for the highest Lys:DE treatment compared with the lowest. Reducing Lys:DE ratio did not modify meat quality traits. A high Lys:DE ratio was associated with a high lean meat percentage. Differences between the medium- and low-Lys:DE groups were not significant. Lowering the Lys:DE ratio increased (P < 0.05) crude fat and fatty tissue content and decreased (P < 0.05) protein and muscle content in the body. Ash content and bone volume were not affected by Lys:DE ratio (P > 0.05). The chemical composition of the carcass can be predicted with moderate accuracy (R2 = 0.39 to 0.58) using volumetric composition data of previously frozen carcasses. In conclusion, similar growth performance, carcass and meat quality, and body composition can be expected if diet formulation is based on the apparent ileally digestible amino acid contents of feedstuffs, independent of dietary protein sources. Diminishing Lys:DE ratios reduce growth performance but do not modify meat quality traits. The chemical composition of the carcass can be predicted with moderate accuracy using the volumetric composition of thawed carcasses.

Animal Feed↗

Effect of stunning current frequency on carcass downgrading and meat quality of turkey.

The objective of this study was to determine the effect of frequency of a 150 mA water-bath stunning current on turkey hen carcass and meat qualities. Fifty turkey hens were subjected to water-bath stunning with alternating current of various frequencies: 50 Hz (n = 12), 300 Hz (n = 14), 480 Hz (n = 12), and 600 Hz (n = 12); the duration of stunning was 4 s for each bird. Carcass defects such as engorged wing veins, red wing tips, and hemorrhages were recorded. Turkey meat quality traits (M. Pectoralis major) were assessed based on rigor mortis development, color, drip loss, cooking loss, tenderness, and cooking yield of cured products. The data showed that frequencies of 480 Hz and 600 Hz are associated with an increased rate of postmortem pH decline (during bleeding). This effect is most likely due to the occurrence of vigorous wing flapping during the first 3 min poststunning. Under the experimental conditions of the present work, the increase in rate of pH decline after stunning at 480 and 600 Hz did not induce carcass and meat quality defects. However, before any recommendation is given, the influence of stunning frequency on turkey meat quality needs to be evaluated under industrial conditions.

Adenosine Triphosphate↗

Effects of crating and transport on stress and meat quality characteristics in broilers.

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P < 0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P < 0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Analysis of Variance↗

Genetic parameter estimates of meat quality traits in Duroc pigs selected for average daily gain, longissimus muscle area, backfat thickness, and intramuscular fat content.

Using a multitrait animal model BLUP, selection was conducted over seven generations for growth rate (ADG), real-time ultrasound LM area (LMA), backfat thickness (BF), and intramuscular fat content (IMF) to develop a new line of purebred Duroc pigs with enhanced meat production and meat quality. This selection experiment examined 543 slaughtered pigs (394 barrows and 153 gilts) from the first to the seventh generation for meat quality traits. Further, electric impedance and collagen content of loin meat were measured from the fourth to sixth generation. The present study was intended to estimate genetic parameters of the correlated traits of tenderness (TEND), meat color (pork color standard: PCS; lightness = L*), drip loss (DL), cooking loss (CL), pH (PH), electric impedance (IMP), and collagen (COL) of the LM, and the genetic trends of these traits. Respective heritability estimates for IMF, TEND, DL, CL, PCS, L*, PH, IMP, and COL were 0.39, 0.45, 0.14, 0.09, 0.18, 0.16, 0.07, 0.22, and 0.23. Genetic correlations of IMF with ADG and BF were low and positive, but low and negative with LMA. Tenderness was correlated negatively with ADG (-0.44) and BF (-0.59), but positively correlated with LMA (0.32). The genetic correlation between LMA and DL was positive and high (0.64). The genetic correlations of TEND with IMF and COL were low (-0.09 and 0.26, respectively), but a moderate genetic correlation (0.43) between COL and IMF was estimated, suggesting related increases of IMF and connective tissue. Genetic correlations among meat quality traits suggested that when IMF increases, the water holding capacity improves. Genetic trends of meat quality traits showed increased IMF and lighter meat color.

Adipose Tissue↗

Genetics of osteochondral disease and its relationship with meat quality and quantity, growth, and feed conversion traits in pigs.

The main objective of this research was to estimate heritabilities of seven osteochondrosis (OC) lesions in station-tested pigs and their genetic and phenotypic correlations with four meat quality (MQ) traits, the percentage of premium cuts (PPC), daily weight gain (DWG), and feed conversion ratio (FCR). Observed OC lesions were on the head of humerus (HK), condylus medialis humeri (CMH), condylus lateralis humeri (CLH), radius and ulna proximal (RUP), distal epiphyseal cartilage of ulna (DEU), head of femur (FK), and condylus medialis femoris (CMF). Meat quality traits were i.m. fat (IMF), muscle pH at 1 h after slaughter (pH1), muscle pH at 30 h after slaughter (pH30), and light reflectance on muscle (H30). The data set comprised 2,710 animals, of which 1,291 animals had OC records. All traits were analyzed by multiple-trait linear mixed model, with the animal's genetic and common litter effects as random. Fixed effects in the model varied between traits. Each OC lesion was further analyzed by a univariate generalized linear mixed model or, equivalently, "threshold models," assuming logistic, probit (normal), and Poisson distributions of the underlying "liability" to the disease. For OC lesions, estimates of heritability were low on the original "incidence" scale (0.06 for HK to 0.16 for CLH) and moderate to high on the liability scale (0.08 to 0.42). Genetic correlations (r(g)) between OC lesions and most MQ traits and PPC were generally unfavorable. Significant r(g) were -0.44 for DWG-CMH, 0.31 for DWG-CMF, 0.40 for FCR-HK, 0.21 for PPC-CLH, 0.32 for PPC-RUP, 0.30 for PPC-CMF, -0.54 for pH1-CLH, 0.47 for pH1-DEU, -0.34 for pH30-CMH, 0.58 for pH30-DEU, -0.50 for H30-HK, -0.31 for H30-DEU, and 0.31 for H30-CMF. Genetic susceptibilities to some OC lesions within the front leg were positively related to each other (r(g) range = 0.57 to 0.69), but r(g) between front and hind leg OC lesions were mostly negative (range = -0.21 to -0.40). Estimated h2 was 0.60 for PPC, and ranged from 0.12 to 0.66 for MQ traits, 0.28 for DWG, and 0.42 for FCR. Genetic correlations among meat quality and quantity traits ranged from -0.66 to 0.37. This is the first study to report genetic and phenotypic correlations between OC lesions and several meat quality and quantity traits in pigs. These findings will be useful to pig industry, especially in designing breeding programs for robust pigs.

Aging↗

Effects of Sarcocystis miescheriana infection on carcass weight and meat quality of halothane-tested fattening pigs.

Ten halothane-positive pigs (Group A) and ten halothane-negative pigs (Group C) were each infected per os by 50,000 sporocysts of Sarcocystis miescheriana when they had reached a mean body weight of 36 kg. Twelve halothane-positive pigs (Group B) and ten halothane-negative pigs (Group D) served as non-infected controls. Thirteen weeks p.i. (post infection), the pigs were slaughtered and the carcass weights and the number of cystozoites in several muscles were determined. In addition, 11 parameters of meat quality were measured in Musculus longissimus dorsi (M.l.d.) and Musculus semimembranosus (M.s.): pH and temperature 30 min and 24 h p.m. (post mortem), electrical conductance 45 min, 60 min and 24 h p.m., colour brightness (FOP) and rigor values 30 min and 24 h p.m. Additionally, the AMP, ADP, ATP and lactate contents were determined in samples from the M.l.d. The mean carcass weights of the infected pigs (A: 79.9 +/- 6.9 kg; C: 76.3 +/- 11.6 kg) were lower than those of the pigs of the non-infected groups (B: 85.7 +/- 8.0 kg; D: 87.5 +/- 7.0 kg). The pH values at 24 h p.m. were significantly higher in the M.l.d. of infected pigs than in M.l.d. of non-infected pigs. Electrical conductance in the M.s. at 45 min p.m. was significantly higher in the halothane-negative infected pigs, but at 24 h p.m., the mean values of electrical conductance in the M.s. of the pigs of both infected groups were significantly lower than in the control groups. FOP values at 30 min p.m. were raised in the M.l.d. of the halothane-negative infected pigs, but at 24 h p.m., differences between infected and non-infected pigs could no longer be found. Mean rigor values were higher in the pigs of the infected groups at 24 h p.m., but the difference from the non-infected groups was not statistically significant. AMP was reduced only in the meat of halothane-positive infected pigs, while lactate was reduced in both infected groups. Using conventional methods for the determination of meat quality, the hypothesis of impaired meat quality in Sarcocystis-infected pigs could not be confirmed. The meat quality parameters investigated were, in part, better in infected pigs than in non-infected controls.

Adenosine Diphosphate↗

Investigation of a peroxisome proliferator-activated receptor gamma haplotype effect on meat quality and carcass traits in pigs.

Peroxisome proliferator-activated receptor gamma (PPARG) is a key transcription factor that controls adipocyte differentiation and fat deposition in mammals. The primary goal of this study was to investigate PPARG as a candidate gene for meat quality and carcass traits in swine. Part of the PPARG promoter, along with the most 5'-proximal exon of the gene, was amplified by PCR and subsequently screened for polymorphisms by sequencing. A Met59Val substitution was detected in the porcine PPARG gene along with four polymorphisms in the promoter region of the adipose-specific PPARG2. Three of these polymorphisms were chosen for genotyping and tested for association with meat quality, carcass and growth traits, according to the candidate gene approach. More than 1500 animals from different lines and populations were used in the study with records for meat quality and carcass traits. No convincing associations were found between the traits investigated and the PPARG genotypes. It does not appear that variation at the PPARG locus is affecting meat quality, carcass or growth traits in the pig populations studied.

Animals↗

Shackling of broilers: effects on stress responses and breast meat quality.

1. Experiments were conducted to study the welfare and meat quality effects of shackling. In experiment 1, broilers with or without leg problems were shackled (S) for 4 min on a moving line and blood sampled; or handled (H), returned to the crate and sampled after 4 min; or sampled immediately after removal from the crate (control, C). 2. Plasma corticosterone (CORT) concentrations, as measured by radioimmunoassay, were highest in S and lowest in C, while the H group was intermediate. Leg problems had no effect on CORT. 3. In experiment 2, tonic immobility (TI) was induced in broilers after 2 min inverted handling to determine fear responses. One week later, the birds were fasted, transported and then shackled on a moving shackle line for 0, 1, 3 or 4 min, then unshackled and blood sampled. Wing flapping during shackling was also quantified. 4. Shackling time did not influence CORT concentrations. There was a negative correlation (r = -0.714) between CORT and wing flapping duration in the 1 min shackling treatment. There was no relationship between TI and wing flapping or CORT. 5. In experiment 3, broilers were exposed to two food withdrawal (FW) times (food withdrawn overnight or during crating only) and held for 4 h prior to processing, shackled (0, 2 or 4 min shackling time, ST), and then killed by exsanguination. Blood samples were collected during the neck-cut. Pectoralis superficialis and Supracoracoideus samples were either collected after 15 min and individually quick frozen (IQF) in liquid nitrogen or collected at 4 h post mortem from carcases chilled on slush ice (COI). 6. CORT increased significantly with increased ST. There was a FW x ST interaction effect on the initial pH of fillets. ST influenced the b*, chroma and Hue values of the COI fillets. FW influenced the L* and Hue values of both IQF and COI fillets as well as the a* value of the COI fillets. 7. In summary, CORT increased with shackling time when birds were held after transport. FW and ST also influenced the colour of fillets, although it is not clear whether these changes are perceptible to the consumer. The duration of wing flapping during shackling did not appear to be related to fearfulness, although it was influenced by properties of the shackle line. We suggest that there be a maximum time lapse between shackling and stunning or killing of 2 min to minimise stress and meat quality changes.

Abattoirs↗