Growth, carcass, fiber type, and meat quality characteristics in Large White pigs with different live weights

Postmortem Metabolism and Pork Quality Development Are Affected by Electrical Stimulation across Three Genetic Lines

Variations in postmortem metabolism in muscle impact pork quality development. Curiously, some genetic lines are more refractile to adverse pork quality development than others and may regulate energy metabolism differently. The aim of this study was to challenge pork carcasses from different genetic populations with electrical stimulation (ES) to determine how postmortem metabolism varies with genetic line and explore control points that reside in glycolysis in dying muscle. Three genetic populations (GP) were subjected to ES (100 V or 200 V, 13 pulses, 2 s on/2 s off) at 15- or 25-min post-exsanguination, or no stimulation (NS). Genetic population affected relative muscle relative abundance of different myosin heavy chains, glycogen, G6P, and lactate concentrations. Genetic lines responded similarly to ES, but a comparison of ES treatment groups revealed a trend for an interaction between voltage, time of ES, and time postmortem. Higher voltage accelerated pH decline at 20 min up to 60 min postmortem. Trends in color and firmness scores and L* values were consistent with pH and metabolite data. These data show that genetic populations respond differently to postmortem perturbation by altering glycolytic flux and suggest differences in postmortem glycolysis may be partially responsible for differences in meat quality between genetic populations, though not entirely.

Dietary leucine and fish oil cooperatively regulate skeletal myofiber type transformation via the CaMKII signaling pathway of pigs

The study investigated the effects of dietary leucine (Leu) and fish oil (FO) on skeletal myofiber type transformations in pigs and their potential interactions. The results showed that Leu increased the content of Leu, upregulated myocyte enhancer factor-2C (MEF2C) and activated the CaMKII-AMPK/SIRT1-PGC-1α pathway in the longissimus dorsi (LD) muscle. FO increased adiponectin and fatty acid beta-oxidation of LD muscle. Activation of the adiponectin signaling pathway by FO further enhanced the CaMKII pathway and upregulated the expression of MEF2C. Moreover, we found that Leu increased cyclic AMP and caffeine, and FO increased linoleic acid and glutamine in muscle metabolites, which may be the cause of myofiber conversion. In conclusion, this study demonstrated that dietary Leu and FO co-regulated the transformation from glycolytic to oxidative skeletal myofiber type. It is hypothesized that there is an interaction between amino acids and polyunsaturated fatty acids, possibly via the CaMKII signaling pathway to upregulate MEF2 and mitochondrial biogenesis.

Potential Mechanism and Effects of Different Selenium Sources and Different Effective Microorganism Supplementation Levels on Growth Performance, Meat Quality, and Muscle Fiber Characteristics of Three-Yellow Chickens

A trial was conducted to investigate the effects of different Se sources, including sodium selenite (S-Se) and selenium yeast (Y-Se) and different effective microorganism (EM) addition levels on growth performance, meat quality, and muscle fiber characteristics of three-yellow chickens and its potential mechanism. A total of 400 birds were randomly distributed into 4 groups (S-Se, S-Se + EM, Y-Se, and Y-Se + EM groups) consisting of a 2 × 2 factorial arrangement. The main factors were the source of Se (I_Se = inorganic Se: 0.2 mg/kg S-Se; O_Se = organic Se: 0.2 mg/kg Y-Se) and the level of EM (H_EMB = high EM: 0.5% EM; Z_EMB = low EM: 0% EM). Each treatment had 5 replicates and each replicate consisted of 20 broiler chickens. The trial lasted for 70 days. The results showed that, in breast muscle, the broiler chickens fed O_Se source decreased the pH_24h, drip loss, shear force, perimeter, cross-sectional area, and diameter, but increased the a24h* and density compared with the broiler chickens fed I_Se source (p < 0.05); broiler chickens supplied with H_EMB level decreased the cross-sectional area and diameter, but increased the pH_24h, a24h,* and density compared with the broiler chickens supplied with Z_EMB level (p < 0.05). In thigh muscle, O_Se source and H_EMB level also could improve the meat quality and change muscle fiber characteristics of broiler chickens (p < 0.05). Meat quality was correlated with the muscle fiber characteristics (p < 0.05). O_Se source and H_EMB level could regulate the expression levels of muscle fiber-relative genes in the breast and thigh muscles (p < 0.05). In conclusion, O_Se source and H_EMB level could improve the meat quality of the breast and thigh muscles of three-yellow chickens by changing the muscle fiber characteristics, and they changed the muscle fiber characteristics by regulating the expression levels of muscle fiber-relative genes.

Effects of carcass weight increase on meat quality and sensory properties of pork loin

The objective of this study was to investigate the influence of increasing carcass weight (CW) on meat quality traits including meat color, water-holding capacity (WHC), tenderness, backfat thickness and intramuscular fat (IMF) content of pork loin. A total of 96 pork carcasses (48 LYD [Landrace × Yorkshire × Duroc] barrows and gilts) were selected at a commercial slaughterhouse. Each gender had commercial CW (≤ 90 kg), heavy CW (91-100 kg) and very heavy CW (> 100 kg) (16 carcasses from each CW group). Loin cuts (Longissimus lumborum) were excised to investigate meat color (CIE L*a*b*), drip loss, cooking loss, released water, Warner-Bratzler shear force (WBSF), and IMF content. Backfat thickness and IMF content of pork loin samples were significantly (p < 0.05) increased with increasing CW, although there was no significant difference in ultimate pH (pHu). CIE a* increased significantly (p < 0.05) with increasing CW, while there were no significant differences in CIE L* or CIE b* among CW groups. Although all WHC measures showed no significant differences among CW groups, WBSF increased significantly (p < 0.01) with increasing CW. Sensory flavor score was significantly increased while panel score for tenderness was decreased significantly (p < 0.001) with increasing CW. Consequently, CW had a positive correlation with flavor but negative correlation with tenderness. These results indicate that the increased IMF content improves flavor, juiciness and palatability, although tenderness deteriorates with increasing CW.

Effect of long-term dietary probiotic Lactobacillus reuteri 1 or antibiotics on meat quality, muscular amino acids and fatty acids in pigs

This study investigated effects of 175-d dietary treatment with Lactobacillus reuteri 1 (LR1) or antibiotics (olaquindox and aureomycin) on the longissimus thoracis (LT) of pigs. Results showed that antibiotics decreased pork quality by increasing drip loss, shear force, and altering myofiber characteristics including diameter, cross-sectional area and myosin heavy chain isoforms compared to LR1. Pigs fed antibiotics had lower muscle contents of free glutamic acid, inosinic acid, and higher glutamine compared to pigs fed the controls and LR1 diets (P ≤ .05). Furthermore, antibiotics decreased free isoleucine, leucine, methionine in LT compared to the control (P ≤ .05). Compared to antibiotics, LR1 likely improved protein synthesis by modulating expression of amino acid transport and ribosomal protein S6 kinase 1 (S6K1) genes, and altered fatty acid profile by regulating metabolic pathways. Overall, LR1 improved pork quality compared to antibiotics by decreasing drip loss and shear force, increasing inosinic acid and glutamic acid that may improve flavor, and altering muscle fiber characteristics.

The efficiency of pig breeding by maturity and bacon thickness at different selection intensities

Scientific and economic experience in the study of the comparative effectiveness of using simultaneous and sequential selection at its various intensities (75, 50 and 30% in boars and 30% in breeding sows) by early maturity and thickness of bacon, aimed at improving feeding and meat qualities, established that simultaneous selection by a set of characters is possible, because connections between them in either the positive or the negative direction have not been identified. However, when one of the traits during prolonged selection improves by an excessive amount, other non-breeding traits deteriorate. At the same time, simultaneous and sequential selection by the early maturity and thickness of the bacon makes it possible to select the same animals for further breeding, regardless of the intensity of the rejection. A different level of producers’ selection intensity (75, 50, 30%) and the same breeding sows (30%) in terms of early maturity and bacon thickness ensure an improvement in these characteristics by an unequal value during one generation.

Correlations of Sensory Quality Characteristics with Intramuscular Fat Content and Bundle Characteristics in Bovine Longissimus Thoracis Muscle

The aim of this study was to investigate the relation of sensory quality traits of cooked beef to fresh meat quality and histochemical characteristics, especially muscle bundle traits, in the longissimus thoracis muscle of Hanwoo steers. Cooking loss negatively correlated with softness, initial tenderness, chewiness, rate of breakdown (RB), and amount of perceptible residue (AR) after chewing (p<0.05), and drip loss showed negative correlation with RB and AR (p<0.05). All the attributes of tenderness exhibited negative correlation with the Warner-Bratzler shear force value (p<0.05). Marbling score and the intramuscular fat (IMF) content showed positive correlation with all the organoleptic characteristics, including tenderness attributes, juiciness, and flavor (p<0.05). Regarding histochemical characteristics, muscle fiber size did not have a significant correlation with all the sensory quality traits, although the area percentage of type I fiber was related with softness, initial tenderness, and chewiness (p<0.05). On the contrary, the characteristics of muscle bundle were related to all the sensory tenderness attributes (p<0.05), and the sensory tenderness increased with smaller muscle bundle size (p<0.05). These results suggest that the IMF content and bundle characteristics can be used as indicators for explaining the variations in sensory tenderness in well-marbled beef.

Correlation of Marbling Characteristics with Meat Quality and Histochemical Characteristics in Longissimus Thoracis Muscle from Hanwoo Steers

The objective of this study was to investigate the correlations of marbling characteristics, including marbling score, intramuscular fat (IMF) content, and fleck traits, with meat quality traits and histochemical characteristics of the longissimus thoracis muscle from Hanwoo steers. Marbling fleck characteristics, especially area, number, and fineness (F) index, measured by computerized image analysis were strongly correlated with marbling score and IMF content (p<0.05). However, coarseness (C) index and F/C ratio were somewhat limited relationships with marbling score. In contrast, the IMF content and the number of smaller white flecks increased with increasing lightness value (p<0.05). Moreover, beef with higher marbling scores showed lower cooking loss and Warner-Bratzler shear force value compared to beef with lower marbling scores (p<0.05). Regarding the muscle bundle traits, as number of bundle increased, number of marbling flecks increased (p<0.05), although most marbling characteristics did not have significant correlation with muscle fiber or bundle characteristics.

Characteristics of selected pork muscles 45 min and 24 h post mortem

The muscles of the pork topside – musculus adductor (AD) and m. semimembranosus (SM), and of the silverside – m. biceps femoris (BF) and m. semitendinosus (ST) were analysed and their properties compared with the m. longissimus thoracis (LT) and m. supraspinatus (SS) muscles. Colour (CIE L*a*b*), D/L-lactic acid content, and pH values were measured 45 min and 24 h post mortem. The basic chemical composition of muscles was analysed 24 h after slaughtering. A significant correlation (r = -0.61, P < 0.001) was found between the pH values and the level of lactic acid 45 min post mortem, though not 24 h after slaughter (r = -0.25, P > 0.05). The results confirmed that a direct comparison cannot be made between the fall in pH values in meat and the increase in the level of lactic acid. The lightness L* 24 h post mortem was higher (P < 0.05) in AD, BF, ST and LT muscles than those in samples measured 45 min after slaughter. The toughest muscle was biceps femoris, with a mean value of shear force of 90.5 N. The differences in shear force between the individual analysed muscles were significant (P < 0.05). There were significant differences in the intramuscular fat content between the topside and silverside muscles (P < 0.05). The results of the present study are of value to meat producers who might intend to substitute these parts of the leg with one another during the production, particularly in the case of whole-muscle meat products.

Effects of slaughter weight and growth rate on the longissimus muscle metabolic characteristics, and pork sensory quality in pigs of two sexes

A total of 119 pigs were used to investigate the effect of slaughter weight (107, 115, and 125 kg), growth rate (fast vs. slow), and sex (barrows vs. gilts) on the longissimus muscle biochemical and sensory traits. Increasing slaughter weight to 125 kg resulted in greater postmortem activity of calpastatin (P = 0.01), lactate dehydrogenase (P = 0.01), and citrate synthase (P = 0.02). Pork toughness and juiciness at 6 d were affected by the interaction slaughter weight × growth rate × sex, with pork being tougher (P = 0.04) and juicer (P = 0.03) in slow-growing gilts slaughtered at 125 and 115 kg, respectively. Flavour was scored higher (P = 0.03) in pork from gilts than from barrows. Overall, based on the slight and likely undetectable differences by the average consumer in the meat sensory traits, it can be concluded that slaughter weight can be increased to 125 kg without appreciable effect on the sensory properties.

Effects of persimmon peel supplementation on pork quality, palatability, fatty acid composition, and cholesterol level

BACKGROUND

The objectives of this study were to investigate the effects of persimmon peel (PPM) supplementation on carcass performance, pork quality, eating quality, fatty acid composition, and cholesterol concentration of the porcine longissimus dorsi muscle.

RESULTS

No adverse effects of PPM supplementation were observed on carcass and meat quality characteristics among the treatment groups (P > 0.05), whereas pork loins from pigs fed a diet supplemented with 0.9 % persimmon peel (T3) showed more tender meat than did pork loins from pigs fed a control diet (P < 0.01), even though no significant difference was observed between the control and T1 group. The T3 group had higher ratio of polyunsaturated fatty acids relative to saturated fatty acids (0.33 vs. 0.28, P < 0.05) and lower total cholesterol concentration (94.4 vs. 99.1 mg/g, P < 0.05) compared to the control group. Persimmon peel appeared to have beneficial effects on fatty acid composition and cholesterol concentration, probably leading to a hypocholesterolemic effect.

CONCLUSIONS

Animal diets fortified with persimmon peel represents an efficient and useful method for improving the nutritional quality of pork without impairing growth performance and eating quality properties.

Carcass Performance, Muscle Fiber, Meat Quality, and Sensory Quality Characteristics of Crossbred Pigs with Different Live Weights

In order to attain heavier live weight without impairing pork or sensory quality characteristics, carcass performance, muscle fiber, pork quality, and sensory quality characteristics were compared among the heavy weight (HW, average live weight of 130.5 kg), medium weight (MW, average weight of 111.1 kg), and light weight (LW, average weight of 96.3 kg) pigs at time of slaughter. The loin eye area was 1.47 times greater in the HW group compared to the LW group (64.0 and 43.5 cm(2), p<0.001), while carcass percent was similar between the HW and MW groups (p>0.05). This greater performance by the HW group compared to the LW group can be explained by a greater total number (1,436 vs. 1,188, ×10(3), p<0.001) and larger area (4,452 vs. 3,716 μm(2), p<0.001) of muscle fibers. No significant differences were observed in muscle pH45 min, lightness, drip loss, and shear force among the groups (p>0.05), and higher live weights did not influence sensory quality attributes, including tenderness, juiciness, and flavor. Therefore, these findings indicate that increased live weights in this study did not influence the technological and sensory quality characteristics. Moreover, muscles with a higher number of medium or large size fibers tend to exhibit good carcass performance without impairing meat and sensory quality characteristics.

Polymorphisms of the porcine cathepsins, growth hormone-releasing hormone and leptin receptor genes and their association with meat quality traits in Ukrainian Large White breed

Cathepsins, growth hormone-releasing hormone (GHRH) and leptin receptor (LEPR) genes have been receiving increasing attention as potential markers for meat quality and pig performance traits. This study investigated the allele variants in four cathepsin genes (CTSB, CTSK, CTSL, CTSS), GHRH and LEPR in pure-bred Ukrainian Large White pigs and evaluated effects of the allele variants on meat quality characteristics. The study was conducted on 72 pigs. Genotyping was performed using PCR-RFLP technique. Meat quality characteristics analysed were intramuscular fat content, tenderness, total water content, ultimate pH, crude protein and ashes. A medium level of heterozygosity values was established for GHRH and LEPR genes which corresponded to very high levels of informativeness indexes. Cathepsins CTSL, CTSB and CTSK had a low level of heterozygosity, and CTSS did not segregate in this breed. Association studies established that intramuscular fat content and tenderness were affected by the allele variance in GHRH and LEPR but not by CTSB and CTSL genes. The GHRH results could be particularly relevant for the production of lean prime cuts as the A allele is associated with both, a lower meat fat content and better tenderness values, which are two attributes highly regarded by consumers. Results of this study suggest that selective breeding towards GHRH/AA genotype would be particularly useful for improving meat quality characteristics in the production systems involving lean Large White lines, which typically have less than 2 % intramuscular fat content.

Skeletal muscle characterization of Japanese quail line selectively bred for lower body weight as an avian model of delayed muscle growth with hypoplasia

This study was designed to extensively characterize the skeletal muscle development in the low weight (LW) quail selected from random bred control (RBC) Japanese quail in order to provide a new avian model of impaired and delayed growth in physically normal animals. The LW line had smaller embryo and body weights than the RBC line in all age groups (P<0.05). During 3 to 42 d post-hatch, the LW line exhibited approximately 60% smaller weight of pectoralis major muscle (PM), mainly resulting from lower fiber numbers compared to the RBC line (P<0.05). During early post-hatch period when myotubes are still actively forming, the LW line showed impaired PM growth with prolonged expression of Pax7 and lower expression levels of MyoD, Myf-5, and myogenin (P<0.05), likely leading to impairment of myogenic differentiation and consequently, reduced muscle fiber formation. Additionally, the LW line had delayed transition of neonatal to adult myosin heavy chain isoform, suggesting delayed muscle maturation. This is further supported by the finding that the LW line continued to grow unlike the RBC line; difference in the percentages of PMW to body weights between both quail lines diminished with increasing age from 42 to 75 d post-hatch. This delayed muscle growth in the LW line is accompanied by higher levels of myogenin expression at 42 d (P<0.05), higher percentage of centered nuclei at 42 d (P<0.01), and greater rate of increase in fiber size between 42 and 75 d post-hatch (P<0.001) compared to the RBC line. Analysis of physiological, morphological, and developmental parameters during muscle development of the LW quail line provided a well-characterized avian model for future identification of the responsible genes and for studying mechanisms of hypoplasia and delayed muscle growth.

Muscle fiber characteristics of pectoralis major muscle as related to muscle mass in different Japanese quail lines

The objectives of this study were to investigate the muscle fiber characteristics of the pectoralis major muscle, and its relation to growth performance in the random bred control (RBC) and heavy weight (HW) Japanese quail lines at 42 days of age. The HW line had greater body (232.0 v. 100.2 g, P < 0.001) and pectoralis major muscle (19.0 v. 6.2 g, P < 0.001) weights than the RBC line. Color differences were observed between the superficial and deep regions of the pectoralis major muscle, with the superficial region showing a higher value of lightness than the deep region of the RBC or HW lines (P < 0.001). The percentage of the superficial region in the pectoralis major muscle was higher in the HW line compared with the RBC line (46.2% v. 38.0%, P = 0.017). There were no significant differences in the total fiber number in the superficial and deep regions between the two quail lines (P = 0.718). The HW quail line showed a larger mean fiber cross-sectional area (CSA; 375.5 v. 176.6 μm², P < 0.001) and type IIA fiber CSA (243.7 v. 131.9 μm², P < 0.001) than the RBC quail line. The HW line also had greater CSA percentage (60.2% v. 34.2%, P < 0.001) and number percentage (41.6% v. 14.2%, P < 0.001) of type IIB fibers, although there were no significant differences in type IIB fiber CSA between the RBC and HW lines (P = 0.219). Therefore, greater body and muscle weights of the HW line are caused by differences in muscle fiber characteristics, especially the proportion of type IIB fiber and the CSA of type IIA fiber, compared with the RBC line. The results of this study suggest that muscle fiber hypertrophy has more impact on body and muscle weights of the different quail lines than muscle fiber hyperplasia.