Muscle fat composition of pheasants (<Emphasis Type="Italic">Phasianus colchicus)</Emphasis>, wild ducks (<Emphasis Type="Italic">Anas platyrhynchos</Emphasis>) and black coots (<Emphasis Type="Italic">Fulica atra</Emphasis>)

The aim of this investigation was to characterise the fatty acid composition within intramuscular fat (IMF) of two muscles (breast and thigh) from 28 pheasants, ten wild ducks and 27 black coots from Slovakia. A high variability for all single fatty acids (FA) and the total fat concentration in muscles of wild birds was identified. Black coots deposited the highest fat in breast muscle whereas wild ducks and pheasants accumulated more lipids in thigh muscle. In general, the content of polyunsaturated fatty acids (PUFA) of the IMF in wild bird muscles was high, and the saturated FA concentration was lower compared with muscles of domestic farm animals. The ratio between PUFA and saturated fatty acids (PSQ) ranked between 0.6 and 1.2, and the ratio of n-6/n-3 fatty acid was favourably low in black coot and wild pheasants (3.2 and 2.9, respectively). Farmed pheasants had increased IMF and more saturated and n-6 fatty acids deposited in thigh muscle but not in breast muscle.     

Does the chicken genotype ‘Géline de Touraine’ have specific carcass and meat characteristics?

The aim of this study was to determine the specific characteristics of carcass and meat from an old French chicken breed, the ‘Géline de Touraine’ (GT), characterised by a very slow-growing rate and usually slaughtered at 120 days of age. For this purpose, we compared the GT with an experimental crossbreed (EC) exhibiting the same growth rate, and with a ‘Label rouge’ (LR) genotype usually slaughtered at 84 days of age. A total of 250 males and 250 females per genotype were reared by separating sexes and genotypes. The growth performances were recorded. At 84 days of age, 80 birds per sex and per genotype were slaughtered. The frequency of clawing and pecking injuries on the carcass was noted. We also measured the skin colour and the thickness of wing membrane. The relative percentages of carcass, breast, thigh + drumstick, abdominal fat, testis or ovary to body weight were determined. On breast and thigh muscles the ultimate pH (pHu) and colour were measured. The juice loss after 3 days’ storage at +4°C and after cooking at 85°C, and the shear force value of Warner–Bratzler were only measured on breast muscles. At 120 days of age, we repeated the same measurements but only on EC and GT genotypes in order to compare birds at the same age or at the respective slaughter age for each production. Whatever the slaughter age, the body weight of males was always higher than that of the females but the carcass yield was similar for both sexes. The females had higher breast yield and carcass fatness but lower thigh + drumstick yield than the males. The yellowness of skin and meat was higher for the females than for the males while the contrary was observed for the redness of the meat. The breast meat of the females also had higher cooking loss than that of the males. GT and EC birds exhibited a higher occurrence of carcass defects and a higher pHu in meat than LR birds. The GT chickens were characterised by a lower breast yield, a higher fattiness and an earlier sexual maturity than the other genotypes, which could confer typical sensorial attributes to their meat. Finally, the EC chickens exhibited a skin and a meat more coloured than the other genotypes, particularly for yellowness, a character which could be under genetic control.     

Influence of carcass suspension on meat quality of Charolais heifers from two sustainable feeding regimes

This study investigated the effects of pelvic suspension on the meat quality of M. longissimus dorsi, M. semimembranosus and M. adductor from 35 heifers with at least 75% Charolais breeding. Two-thirds of the heifers were slaughtered directly from pasture at 18 months of age and one-third was finished indoors and slaughtered at 22 months. After slaughter and electrical stimulation one side of each carcass was re-suspended by either the achilles tendon or the pelvic bone. Longissimus muscles were aged 7 or 14 days and were then evaluated for drip loss, colour, shear force and sensory analysis. As compared to 18-month-old heifers, 22-month-old heifers were heavier, more muscular and fatter (P < 0.05). Intramuscular fat content increased with slaughter age (P < 0.003). Pelvic suspension reduced longissimus peak force values, total energy, pH and thawing losses (P < 0.05) in heifers slaughtered at 18 months. Semimembranosus showed the largest response to pelvic suspension with significantly lower peak force and total energy values. Finishing for 4 months did not affect longissimus shear forces. Achilles-suspended samples had lower shear force values after 14 v. 7 days of ageing. Pelvic-suspended samples aged 7 days were, however, just as tender as those aged 14 days. Sensory analysis of longissimus samples aged 14 days showed that samples from pelvic-suspended sides had higher tenderness, lower bite resistance, more meaty taste and less visible marbling compared with samples from achilles-suspended carcasses.     

Mitochondrial respiratory and antioxidative enzyme activities in broiler meat in relation to age and gender of the animals

Colour is an important quality parameter of broiler meat influencing the consumer buying behaviour. The alterations of the colour after slaughter are related to the oxidative status of the tissue. This in turn is influenced by an interaction between the mitochondria and the antioxidative enzymes. In this study, breast muscles were collected from hens and cocks of a commercial line slaughtered at the ages of 28 and 41 day. Analysis of the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) was performed with samples obtained 20 min and 48 h after slaughter (post mortem, p.m.), whereas the mitochondrial respiratory activity was analysed in permeabilised breast muscle fibres collected 20 min p.m. The carcass characteristics of breast muscle and leg weight as well as breast yield were significantly higher, and the leg yields lower, in the 41-day-old broiler. The 28-day-old hens and cocks had comparable carcass characteristics (P > 0.05), whereas 41-day-old cocks had significantly higher carcass, breast and leg weight in comparison to the hens. The pH20 min p.m. and the L*48 h p.m. were significantly higher, and the a* and b* values of the 20 min and 48 h p.m. samples as well as the drip loss were significantly lower in the 41-day-old broiler. Mitochondrial respiratory rates were comparable (P > 0.05) between the 28- and 41-day-old cocks and hens. The same result could be found with regard to the activities of the SOD, GPx and GR except for lower activities of the SOD20 min p.m. and higher of the GR48 h min p.m. in the 41-day-old broiler. The concentrations of thiobarbituric acid-reactive substances were generally higher in the breast muscles of the 41-day-old broiler. Assorting the data according to their mean pH20 min p.m. indicates a positive influence of higher pH values (>6.34) on the mitochondrial function, whereas a low pH20 min p.m. results in tendentially and significantly higher activities of the antioxidative enzymes and drip loss values. These results indicate a relation between the meat quality and the oxidative metabolism as well as antioxidative capacity of the meat.     

The Influence of Naringin or Hesperidin Dietary Supplementation on Broiler Meat Quality and Oxidative Stability

An experiment was conducted to examine the effects of supplementing broiler feed with hesperidin or naringin, on growth performance, carcass characteristics, breast meat quality and the oxidative stability of breast and thigh meat. Two hundred and forty 1-day-old Ross 308 broiler chickens were randomly assigned to 6 groups. One of the groups served as a control (C) and was given commercial basal diets, whereas the other five groups were given the same diets further supplemented with naringin at 0.75 g/kg (N1), naringin at 1.5 g/kg (N2), hesperidin at 0.75 g/kg (E1), hesperidin at 1.5 g/kg (E2) and a-tocopheryl acetate at 0.2 g/kg (E). At 42 days of age, 10 chickens per treatment group were slaughtered for meat quality and oxidative stability assessment. No significant differences were observed among groups in final body weight, carcass weight and internal organs weights (P>0.05) apart from liver that decreased linearly with increased levels of naringin (P-linear<0.05). Regarding the breast meat quality parameters, only redness (a*) value was higher in E1 and N1 group compared to VE group (P<0.05), while all the others i.e. shear values (N/mm²), pH₂₄, cooking loss (%) and L* and b* color parameters were not significantly different among groups (P>0.05). Measurement of lipid oxidation values showed that after hesperidin and naringin dietary supplementation, malondialdehyde values decreased in tissue samples in a dose depended manner (P-linear<0.05). In conclusion, hesperidin and naringin, positively influence meat antioxidative properties without negative implications on growth performance and meat quality characteristics in poultry, thus appearing as important additives for both the consumer and the industry.     

Influence of keeping pheasants in captivity vs. nature on the biological value of meat and its use in human nutrition

The life of game birds (pheasants) in nature is coupled with a number of difficulties in all seasons of the year. This refers to finding food, breeding, laying eggs, raising the young, fleeing from their natural enemies and lack of protection from unfavorable climatic conditions. The pheasants that live in captivity--aviaries for pheasants--do not have such difficulties--they are fed regularly by quality feed for pheasants, they are protected from bad weather and natural enemies. Our research was aimed at determining the biological value of meat of pheasants grown in the two different settings--in captivity and in nature. The highest weight achieved wild pheasant males (1232.4 +/- 147.36 g). The differences between tested pheasant groups were statistically very high significant (P < 0.001). The differences between groups related to breast weight and tights with drumsticks weight were statistically very high significant (P < 0.001). Between breast parts (%) and legs parts (%) were notified very high (P < 0.001) i.e. high (P = 0.002) differences. The highest weight breast muscles and tights with drumsticks had wild pheasants (282.6 +/- 63.53 g i.e. 206.2 +/- 37.88g). Wilde pheasants had lower part (%) and lighter (g) skin with subcutaneous fatty tissue on breasts. Female pheasants cultivated on both ways had higher skin part (%) and subcutaneous fatty tissue in tights with drumsticks. Related to chemical composition of breast muscles is established statistically significant differences (P < 0.001 i.s. P = 0.040)) in part of Ca (%) and P (%). In wild pheasant tights with drumsticks muscles established statistically very significant (P < 0.001) higher part of moisture, protein and Ca, i.e. statistically very high significant (P < 0.001) lower part of fat and energetic value. Research results indicate that the quality of meat of pheasants grown in nature has higher biological value than the meat of pheasants kept in aviaries, which means it has advantages in human nutrition.     

Implications of white striping and wooden breast abnormalities on quality traits of raw and marinated chicken meat

One of the consequences of intense genetic selection for growth of poultry is the recent appearance of abnormalities in chicken breast muscles, such as white striping (characterised by superficial white striations) and wooden breast (characterised by pale and bulged areas with substantial hardness). The aim of this study was to evaluate the quality traits of chicken fillets affected by white striping and wooden breast abnormalities. In two replications, 192 fillets were divided into the following four classes: normal (n=48; absence of any visual defects), white striping (n=48, presence of white striations), wooden breast (n=48; diffusely presence of hardened areas) and white striping/wooden breast (n=48; fillets affected by both abnormalities). Morphology, raw meat texture and technological properties were assessed in both unprocessed (pH, colour, drip loss, cooking loss and cooked meat shear force) and marinated meat (marinade uptake, purge loss, cooking loss and cooked meat shear force). Fillets affected by white striping, wooden breast or both abnormalities exhibited higher breast weights compared with normal fillets (305.5, 298.7, 318.3 and 244.7 g, respectively; P<0.001). Wooden breast, either alone or in combination with white striping, was associated with a significant (P<0.001) increase of fillet thickness in the caudal area and raw meat hardness compared with both normal and the white striping abnormality, for which there was no difference. Overall, the occurrence of the individual and combined white striping and wooden breast abnormalities resulted in substantial reduction in the quality of breast meat, although these abnormalities are associated with distinct characteristics. Wooden breast fillets showed lower marinade uptake and higher cooking losses than white-striped fillets for both unprocessed and marinated meats. On the other hand, white-striped fillets showed a moderate decline in marinade and cooking yield. Fillets affected by both abnormalities had the highest (P<0.001) ultimate pH values. In contrast, the effects on colour of raw and cooked meat, drip loss, purge loss and cooked meat shear force were negligible or relatively low and of little practical importance. Thus, the presence of white striping and wooden breast abnormalities impair not only breast meat appearance but also the quality of both raw and marinated meats mainly by reducing water holding/binding abilities.     

Genetic parameters of meat technological quality traits in a grand-parental commercial line of turkey

Genetic parameters for meat quality traits and their relationships with body weight and breast development were estimated for a total of 420 male turkeys using REML. The birds were slaughtered in a commercial plant and the traits measured included pH at 20 min (pH₂₀) and 24 h post-mortem (pHu) and colour of the breast and thigh meat. The heritabilities of the rate and the extent of the pH fall in the breast muscle were estimated at h² = 0.21 ± 0.04 and h² = 0.16 ± 0.04, respectively. Heritabilities ranging from 0.10 to 0.32 were obtained for the colour indicators in the breast muscle. A marked negative genetic correlation (r_g = -0.80 ± 0.10) was found between pH₂₀ and lightness (L*) of breast meat, both traits corresponding to PSE indicators. The pH₂₀ in the thigh muscle had a moderate heritability (h² = 0.20 ± 0.07) and was partially genetically related to pH₂₀ in the breast muscle (r_g = 0.45 ± 0.17). Body weight and breast yield were positively correlated with both initial and ultimate pH and negatively with the lightness of breast meat.     

Influence of slaughter age and carcass suspension on meat quality in Angus heifers

This study investigated the effects of pelvic suspension and slaughter age on longissimus thoracis et lumborum (LTL) from 40 heifers with at least 75% Angus breeding. A total of 20 heifers were slaughtered directly from pasture at 18 months of age, and carcass sides were hung either by the Achilles tendon or the pelvic bone. The other 20 heifers were assigned to an additional winter housing period and slaughtered at 22 months of age; carcass sides were hung only by Achilles suspension. All carcasses were electrically stimulated and assessed according to the EUROP carcass classification system. In addition, the LTL muscles were aged for 7 or 14 days before meat quality was evaluated for intramuscular fat (IMF), drip loss, colour, shear force, compression and sensory analysis. The 22-month-old heifers were heavier, fatter and had more IMF than 18-month-old heifers. Conformation scores (muscling) did not differ between the two slaughter groups. Pelvic suspension reduced both between- and within-animal variation for peak force, total energy and compression peak force. For the 18-month-old heifers, pelvic suspension also decreased peak force, total energy and compression variables for the LTL muscles from both ageing periods, whereas Achilles-suspended samples had lower shear force values only at day 14. Sensory analysis showed that pelvic-suspended sides had greater tenderness, lower bite resistance, less threadiness, higher juiciness and meat flavour and less visible marbling than meat from Achilles-suspended sides. Pelvic-suspended sides at 18 months of age were similar in peak force and total energy values to the 22-month-old heifers. The importance of ageing the Achilles-suspended sides was more obvious for samples from 18-month-old heifers than from the 22-month-old animals. The correlations between the different instrumental measurements and sensory tenderness were considerably higher for carcasses suspended by the Achilles tendon (r = −0.55 to 0.20) than for those hung by the pelvic bone (r = −0.25 to 0.19). More correlations between sensory-evaluated tenderness and shear variables were significant after 7 days (n = 6) of ageing than after 14 days (n = 4) of ageing. This study clearly shows the benefits of pelvic suspension, which reduces the need for additional feeding after pasture.     

Effect of power, pedal rate, and force on average muscle fiber conduction velocity during cycling.

Muscle fiber conduction velocity (MFCV) provides indications on motor unit recruitment strategies due to the relation between conduction velocity and fiber diameter. The aim of this study was to investigate MFCV of thigh muscles during cycling at varying power outputs, pedal rates, and external forces. Twelve healthy male participants aged between 19 and 30 yr cycled on an electronically braked ergometer at 45, 60, 90, and 120 rpm. For each pedal rate, subjects performed two exercise intensities, one at an external power output corresponding to the previously determined lactate threshold (100% LT) and the other at half of this power output (50% LT). Surface electromyogram signals were detected during cycling from vastus lateralis and medialis muscles with linear adhesive arrays of eight electrodes. In both muscles, MFCV was higher at 100% LT compared with 50% LT for all average pedal rates except 120 rpm (mean +/- SE, 4.98 +/- 0.19 vs. 4.49 +/- 0.18 m/s; P < 0.001). In all conditions, MFVC increased with increasing instantaneous knee angular speed (from 4.14 +/- 0.16 to 5.08 +/- 0.13 m/s in the range of instantaneous angular speeds investigated; P < 0.001). When MFCV was compared at the same external force production (i.e., 90 rpm/100% LT vs. 45 rpm/50% LT, and 120 rpm/100% LT vs. 60 rpm/50% LT), MFCV was higher at the faster pedal rate (5.02 +/- 0.17 vs. 4.64 +/- 0.12 m/s, and 4.92 +/- 0.19 vs. 4.49 +/- 0.11 m/s, respectively; P < 0.05) due to the increase in inertial power required to accelerate the limbs. It was concluded that, during repetitive dynamic movements, MFCV increases with the external force developed, instantaneous knee angular speed, and average pedal rate, indicating progressive recruitment of large, high conduction velocity motor units with increasing muscle force.     

Effect of fast-, medium- and slow-growing strains on meat quality of chickens reared under the organic farming method

The characteristics of meat quality, chemical and fatty acid composition, from fast-growing (FG) and medium-growing (MG) meat-type and slow-growing (SG) egg-type chickens reared under organic conditions were compared. Three-hundred and sixty 1-day-old male chicks, equally divided into three experimental groups represented by strains (FG: Cobb 700, MG: Naked neck Kabir and SG: Brown Classic Lohman) were housed into three poultry houses with outdoor pasture availability of 10 m(2)/bird located in the same Research Centre of the University of Perugia. All the birds were fed ad libitum the same diets formulated according to the European Union (EU) Regulations by using organic raw materials. Birds from the FG and MG groups were raised until 81 days, whereas birds from the SG group were raised until 96 days in order to achieve an acceptable market live weight. SG birds showed significantly (P < 0.01) higher breast meat drip and cook losses, Allo-Kramer shear values and collagen content. In comparison with FG and SG, MG exhibited a higher breast meat pH (5.86% v. 5.79% and 5.78%, respectively; P < 0.01) and a lower lightness (54.88% v. 57.81% and 56.98%, respectively; P < 0.05). Genotype dramatically affected the lipid content as well as the fatty acid composition of both breast and thigh meat. SG exhibited the lowest content of lipid, both in breast and in thigh meat, the lowest proportions of monounsaturated fatty acids (MUFA) and the highest proportions of polyunsaturated fatty acids (PUFA). The total n-3 PUFA of SG breast meat was double that of FG meat and intermediate with respect to MG birds (8.07% v. 4.07% v. 5.14% total fatty acids; P < 0.01). The fatty acid composition of thigh meat is similar to that of breast meat, but the differences among genotypes are less pronounced. Total saturated fatty acids were not affected by the genotype. In conclusion, meat functional properties of FG and MG strains appeared much more attractive both for industry and consumer (lower drip and cook losses and higher tenderness), whereas from a nutritional point of view, meat from SG appeared healthier (less fat and higher content of n-3 PUFA) and thus might better fit with the consumer's expectations of organic products.     

Effect of Oral Zinc Supplementation on the Thiol Oxido-Reductive Index and Thiol-Related Enzymes in Seminal Plasma and Spermatozoa of Iraqi Asthenospermic Patients

Despite increasing evidence indicating the essential involvement of selenium (Se) on growth performance, antioxidant capacity, and meat quality of commercial broilers, the effects of different Se sources on local Chinese Subei chickens is unclear. A total of 360 50-day-old male chickens were individually weighed and randomly allocated to four treatment groups. Chickens in each of the four groups were fed diets supplemented with 0.3 mg Se/kg as sodium Se (SS), Se-enriched yeast (SY), selenomethionine (Met-Se), or nano red element Se (Nano-Se) for 40 days. At the end of the experiment, one bird of approximately average weight from each cage was selected and slaughtered, and blood and breast muscles samples were collected. The results showed that there was no significant difference in feed intake, body weight gain, or feed to gain ratio among treatments (P > 0.05). Dietary SY, Met-Se, and Nano-Se supplementation increased the activity of glutathione peroxidase in serum and breast muscles and decreased the concentration of malondialdehyde in serum and carbonyl in breast muscles compared with the SS group (P < 0.05). Moreover, SY, Met-Se, and Nano-Se supplementation increased pH_45min, total protein solubility, and myofibrillar protein solubility, as well as decreased the shear force value compared with the SS group (P < 0.05). In addition, birds in the SY and Met-Se groups exhibited lower cooking loss compared with the SS group (P < 0.05). In conclusion, organic Se and Nano-Se supplementation resulted in an improvement of antioxidant capacity and meat quality in local Chinese Subei chickens relative to inorganic Se.     

Genetic trend estimates of meat quality traits in a male broiler line

The present research was conducted to estimate the genetic trends for meat quality traits in a male broiler line. The traits analyzed were initial pH, pH at 6 h after slaughter, final pH, initial range of falling pH, final range of falling pH, lightness, redness, yellowness, weep loss, drip loss, shrink loss, and shear force. The number of observations varied between 618 and 2125 for each trait. Genetic values were obtained by restricted maximum likelihood, and the numerator relationship matrix had 107,154 animals. The genetic trends were estimated by regression of the broiler average genetic values with respect to unit of time (generations), and the average genetic trend was estimated by regression coefficients. Generally, for the traits analyzed, small genetic trends were obtained, except for drip loss and shear force, which were higher. The small magnitude of the trends found could be a consequence of the absence of selection for meat quality traits in the line analyzed. The estimates of genetic trends obtained were an indication of an improvement in the meat quality traits in the line analyzed, except for drip loss.     

白腹锦鸡机体营养成分的分析与探讨

本文报道笼养和野生白腹锦鸡机体营养成分及其差异。分析表明,笼养的比野生种营养成分含量高的有:腿肌蛋白质高11％,胸肌、腿肌、全血的氨基酸分别高2.64％,1.39％和4.68％,胸肌、腿肌和肝脏的碳水化合物分别高0.076％、0.092％和3.962％,胸肌和腿肌的维生素A分别高188.63和84.09 I.U.,胸肌和腿肌的维生素D分别高47.2和12.8 I.U.。但是胸肌蛋白质含量笼养的比野生的低26％。     

Effect of white striping on turkey breast meat quality

In the past decades, the intense selection practices carried out in order to develop fast growing and high breast-yield turkey hybrids profoundly modified the muscle physiology leading to the development of growth-related alterations and muscular abnormalities. White striations of variable thickness have been particularly observed on the ventral surface of Pectoralis major muscle belonging from heavy male turkeys since several years. However, although the effects of white striping (WS) have been extensively studied on broilers, this condition was not considered as a main quality issue by both turkey producers and meat industry. Thus, this study aimed at evaluating whether the occurrence of WS in heavy male turkeys affects the quality traits and technological properties of meat to the same extent previously observed for broilers. In two replications, 72 Pectoralis major muscles were classified as: normal (NORM), moderate WS (MOD) and severe WS (SEV) cases. The whole muscle was weighed and cut in order to assess colour, ultimate pH, water holding (drip and cooking losses) and binding (marinade uptake) capacities, NMR relaxation properties, shear force as well as proximate composition of meat. The Pectoralis major muscles affected by WS (both moderate and severe cases) exhibited a one-fifth increased weight in comparison with their NORM counterpart. However, the occurrence of WS only partially affected the proximate composition of the meat. In detail, although moisture, collagen and protein contents did not differ among the groups, if compared with NORM, higher lipid levels were found in SEV muscles, whereas MOD had intermediate values. On the other hand, both MOD and SEV exhibited lower ash content. Despite these variations in proximate composition, both water holding and binding capacities of turkey breast meat were not affected by WS. Indeed, quality traits of raw (pH, colour, cooking losses and shear force) and marinated (uptake, cooking losses and shear force) meat as well as water distribution within the muscle tissue did not differ between NORM and WS cases. Overall, if compared with broilers, WS only marginally affected quality traits of turkey breast meat. It might thus be hypothesised a diverse specie-specific physiological response to the pressure in muscle tissue induced by the selection in turkeys that, although analogously led to the occurrence of WS, results in limited effects on meat quality.     

Effects of Supplemental Copper on the Serum Lipid Profile,Meat Quality,and Carcass Composition of Goat Kids

To evaluate the effects of copper (Cu) supplementation on the serum lipid profile, meat quality, and carcass composition of goat kids, thirty-five 3–4-month-old Jian Yang big-eared goat kids (BW 20.3?±?0.6 kg) were randomly assigned to one of seven dietary Cu treatments (n?=?5/treatment). The dietary Cu concentrations were: (1) control (no supplemental Cu), (2) 20 mg, (3) 40 mg, (4) 80 mg, (5) 160 mg, (6) 320 mg, and (7) 640 mg of supplemental Cu/kg dry matter (DM). Copper was supplemented as CuSO₄.5H₂O (25.2 % Cu). The goats were fed a high-concentrate basal diet with the different concentrations of supplemental Cu/kg DM for 96 days. The serum lipid profile was determined on day 51 and day 96. Meat quality and carcass composition of longissimus dorsi muscle were measured after the goats were slaughtered at 96 days. Serum total cholesterol, triglycerides, high density lipoprotein-cholesterol (HDL-C), and low density lipoprotein-cholesterol (LDL-C) were not affected by treatment (P?>?0.18). No differences were observed in drip loss, cooking loss, a* (redness/greenness) and b* (yellowness/blueness) values (P?>?0.17); however, the 24-h pH value (linear; P?=?0.0009) and L* (brightness) value (linear; P?=?0.0128) decreased, and shear force increased (linear; P?=?0.0005) as Cu supplementation increased. The intramuscular fat (%) increased (linear; P?=?0.001) as supplemental Cu increased. No differences (P?>?0.21) in the moisture, crude protein, and ash (%) were observed. Results of this study indicate that supplemental Cu does not modify the serum lipid profile; however, it can impact intramuscular fat content and the meat quality of goat kids.     

The relationship of pork longissimus muscle pH to mitochondrial respiratory activities,meat quality and muscle structure

The way the pH falls post-slaughter has an impact on meat quality. Pork longissimus muscles (n=48) were sorted in fast- (FG) (n=15) and normal glycolysing (NG) (n=33) muscles according to the post-slaughter pH 45 min values (FG<6.0; NG>6.0). FG muscles (5.84±0.04) compared with NG muscles (6.27±0.04) were accompanied with higher temperature, electrical conductivity, lightness and yellowness, and reduced grill loss and shear force values (P<0.05), but there were no pH-dependent changes of the drip loss and redness results. FG muscles had higher (P<0.05) percentages of fast-twitch glycolytic and lower proportions of fast-twitch oxidative and slow-twitch oxidative (P<0.05) muscle fibres. The study confirms the relationship of pH value to meat quality and muscle fibre characteristics also showing that pH values have no impact on intrinsic mitochondrial respiratory function.     

Combined effect of divergent selection for breast muscle ultimate pH and dietary amino acids on chicken performance,physical activity and meat quality

Responses to changes in dietary Lys and other essential amino acid (AA) concentrations were evaluated in 480 male and female broilers originating from two lines divergently selected for high (pHu+) or low (pHu−) ultimate pH (pHu) of breast muscle. The two genetic lines were fed with two grower isoenergetic diets differing in both true digestible Lys (control=10.2 g/kg and experimental=7.0 g/kg) and amounts of other essential AA calculated in relation to Lys, which were sufficient for the control diet or in excess for the experimental diet. There were six repetitions per treatment. Birds were weighed individually at days 0, 21, 28 and 43. Feed consumption was recorded per pen and feed conversion was calculated over the growing period. The physical activity and walking ability of broilers were recorded during the whole rearing period. Breast and leg yield, and abdominal fat percentage were measured at 43 days of age, as were pHu, color, drip and cooking loss, Warner–Bratzler shear force, and curing-cooking yield of the breast Pectoralis major and pHu of the thigh Sartorius muscle. Divergent selection greatly affected most breast meat quality traits without significantly changing growth rate or feed efficiency. When subjected to a variation in dietary intake of AA, birds from the two genotypes responded in a similar way in terms of animal’s growth, feed efficiency, body composition and meat quality traits. Although line and diet did not affect physical or feeding activities of the broilers, a significant effect of line-by-diet interaction was observed on gait score. Contrary to the pHu− birds, the walking ability of pHu+ birds was impaired when fed the control diet that favored growth and breast muscle development and limited storage of carbohydrate in muscle.     

Quantifying the Elastic Property of Nine Thigh Muscles Using Magnetic Resonance Elastography

BackgroundPathologies of the muscles can manifest different physiological and functional changes. To adapt treatment, it is necessary to characterize the elastic property (shear modulus) of single muscles. Previous studies have used magnetic resonance elastography (MRE), a technique based on MRI technology, to analyze the mechanical behavior of healthy and pathological muscles. The purpose of this study was to develop protocols using MRE to determine the shear modulus of nine thigh muscles at rest.MethodsTwenty-nine healthy volunteers (mean age = 26 ± 3.41 years) with no muscle abnormalities underwent MRE tests (1.5 T MRI). Five MRE protocols were developed to quantify the shear moduli of the nine following thigh muscles at rest: rectus femoris (RF), vastus medialis (VM), vastus intermedius (VI), vastus lateralis (VL), sartorius (Sr), gracilis (Gr), semimembranosus (SM), semitendinosus (ST), and biceps (BC). In addition, the shear modulus of the subcutaneous adipose tissue was analyzed.ResultsThe gracilis, sartorius, and semitendinosus muscles revealed a significantly higher shear modulus (μ_{_Gr} = 6.15 ± 0.45 kPa, μ_{_ Sr} = 5.15 ± 0.19 kPa, and μ_{_ ST} = 5.32 ± 0.10 kPa, respectively) compared to other tissues (from μ_{_ RF} = 3.91 ± 0.16 kPa to μ_{_VI} = 4.23 ± 0.25 kPa). Subcutaneous adipose tissue had the lowest value (μ_{_adipose tissue} = 3.04 ± 0.12 kPa) of all the tissues tested.ConclusionThe different elasticities measured between the tissues may be due to variations in the muscles'' physiological and architectural compositions. Thus, the present protocol could be applied to injured muscles to identify their behavior of elastic property. Previous studies on muscle pathology found that quantification of the shear modulus could be used as a clinical protocol to identify pathological muscles and to follow-up effects of treatments and therapies. These data could also be used for modelling purposes.     

Threshold for shivering in aerobic and anaerobic muscles in bantam cocks and incubating hens

Summary Electromyographic activity (EMG) from the musculus pectoralis (breast muscle), m. iliotibialis (thigh muscle) and m. gastrocnemius (leg muscle), cloacal temperature (Tb) and O₂ consumption were measured in bantam cocks (Gallus domesticus) exposed to different ambient temperatures (Ta). The same parameters were measured in bantam hens incubating eggs artificially thermoregulated to 40° and 25°C (Te).EMG activity appeared in thigh and leg muscles at Ta below 32°C (Tsh). This temperature probably represents the thermoneutral temperature (TNT) of the cock. EMG activity in breast muscles appeared at Ta below 20°C, or 4°C below the lower critical temperature (Tc).All muscles were quiet when the hen incubated 40°C egg at Ta=Tsh. When Te was abruptly changed to 25°C, EMG activity in the iliotibialis muscle appared 3 min before the activity in the pectoralis muscle. Tb dropped from 41.2° to 40.6°C in 14 min. When Te was returned to 40°C, the EMG activity in the pectoralis muscle disappeared almost at once, while the iliotibialis muscle was active until Tb returned to normal.Aerobic muscles seem to be responsible for shivering thermogenesis between Tc and Tsh, while anaerobic muscles are recruited at lower Ta or when the heat loss during incubation becomes severe.Abbreviations EMG electromyography - Ta ambient temperature - Tb cloacal temperature - Tc lower critical temperature - Te egg temperature - TNT thermoneutral temperature - Tsh shivering threshold temperature