Turkey meat is the second most consumed poultry meat worldwide and represents an economic source of high-quality protein for human consumption. To fulfill the increasing demand for turkey meat, breeding companies have been selecting genetic lines with increased growth potential and breast muscle proportion. Moreover, the progressive shift towards further processed products has emphasized the need for higher standards in poultry meat to improve its technological characteristics and functional properties (i.e. water holding capacity). However, as observed for broiler chickens, a growing body of scientific evidence suggests that the intense selection for the above-mentioned traits could be associated with a greater occurrence of growth-related myopathies and abnormalities and, consequently, to increased downgrading rates and overall reduction of meat quality characteristics. In the past, muscle abnormalities such as deep pectoral myopathy, pale-soft-and-exudative (PSE)-like meat, and focal myopathy have been reported in turkey lines selected for increased growth rate. In addition, the presence of white striations in the superficial layer of Pectoralis major muscle, as well as the tendency of muscle fiber bundles to separate resulting in an altered breast muscle structure, have been detected in commercial turkey abattoirs. Furthermore, past investigations revealed the presence of another quality issue depicted by an overall toughening of the breast muscle. These meat abnormalities seem to macroscopically overlap the white-striping, spaghetti-meat and wooden breast conditions observed in pectoral muscle of fast-growing, high breast-yield chicken hybrids, respectively. Considering the high economic impact of these growth-related abnormalities in broilers, there is an increasing interest of the turkey industry in estimating the occurrence and the impact of these meat quality issues also in the modern turkey lines. Studies have been recently conducted to assess the effect of the genotype on the occurrence of these emerging growth-related defects and to evaluate how meat quality properties are affected by white-striping condition in turkeys, respectively. Therefore, this review aims to provide a critical overview of the current understanding regarding the growth-related abnormalities and their impact on meat quality in modern turkey hybrids with the hope that this information may improve the knowledge concerning their overall effect on poultry meat.
During the past few years, there has been an increasing prevalence of broiler breast muscle abnormalities, such as white striping (WS) and wooden breast conditions. More recently, a new muscular abnormality termed as spaghetti meat (SM) because of the altered structural integrity of the Pectoralis major muscle often associated with WS has emerged. Thus, this study aimed at evaluating the effects of WS and SM conditions, occurring alone or combined within the same P. major muscle, on meat quality traits and muscle histology. In two replications, 96 P. major muscles were classified into four classes: normal (N), WS, SM and WS/SM. The whole fillet was used for weight assessment and morphometric measurements, then each sample was cut in order to separate the superficial layer from the deep one and used to evaluate proximate composition, histological features, nuclear magnetic resonance relaxation times, functional properties and both myofibrillar and sarcoplasmic proteins profile. Fillets affected by WS and SM abnormalities exhibited higher weights and increased thickness and length. SM condition was associated with a relevant decrease in protein content coupled with a significant increase in moisture level, whereas fat content was affected only by the simultaneous presence of WS. Histological evaluations revealed that abnormal samples were characterized by several degenerative aspects that almost completely concerned the superficial layer of the fillets. White striped fillets exhibited necrosis and lysis of fibers, fibrosis, lipidosis, loss of cross striation and vacuolar degeneration. Moreover, SM samples were characterized by poor fiber uniformity and a progressive rarefaction of the endo- and peri-mysial connective tissue, whereas WS/SM fillets showed intermediate histological features. Nuclear magnetic resonance relaxation analysis revealed a higher proportion of extra-myofibrillar water in the superficial section of all the abnormal fillets, especially in SM samples, which consequently led to a reduction of the water holding capacity of meat. As for functional properties, abnormal fillets exhibited a lower protein solubility and higher ultimate pH values on both the superficial and deep sections. Although abnormal fillets exhibited higher yellowness values, no relevant effect on meat color was observed. The occurrence of WS and SM abnormalities led to increased carbonylation levels and more intense proteolytic processes. Overall, muscle abnormalities mainly affect the superficial layer of P. major muscle and particularly the occurrence of SM myopathy seems to implicate a more pronounced modification of meat quality traits than the mere presence of WS.
The Minimum Cost of a Nutritious Diet (MCNut) is the cost of a theoretical diet satisfying all nutrient requirements of a family at the lowest possible cost, based on availability, price, and nutrient content of local foods. A comparison with household expenditure shows the proportion of households that would be able to afford a nutritious diet.To explore using the Cost of Diet (CoD) tool for policy dialogue on food and nutrition security in Indonesia.From October 2011 to June 2012, market surveys collected data on food commodity availability and pricing in four provinces. Household composition and expenditure data were obtained from secondary data (SUSENAS 2010). Focus group discussions were conducted to better understand food consumption practices. Different types of fortified foods and distribution mechanisms were also modeled.Stark differences were found among the four areas: in Timor Tengah Selatan, only 25% of households could afford to meet the nutrient requirements, whereas in urban Surabaya, 80% could. The prevalence rates of underweight and stunting among children under 5 years of age in the four areas were inversely correlated with the proportion of households that could afford a nutritious diet. The highest reduction in the cost of the child's diet was achieved by modeling provision of fortified blended food through Social Safety Nets. Rice fortification, subsidized or at commercial price, can greatly improve nutrient affordability for households.The CoD analysis is a useful entry point for discussions on constraints on achieving adequate nutrition in different areas and on possible ways to improve nutrition, including the use of special foods and different distribution strategies.
It is generally held that the content of several free amino acids and dipeptides is closely related to the energy-supplying metabolism of skeletal muscles. Metabolic characteristics of muscles are involved in the variability of meat quality due to their ability to influence the patterns of energy metabolism not only in living animal but also during postmortem time. Within this context, this study aimed at establishing whether the concentration of histidine dipeptides can affect muscle postmortem metabolism, examining the glycolytic pathway of 3 chicken muscles (pectoralis major, extensor iliotibialis lateralis, and gastrocnemius internus as glycolytic, intermediate, and oxidative-type, respectively) selected based on their histidine dipeptides content and ultimate pH. Thus, a total of 8 carcasses were obtained from the same flock of broiler chickens (Ross 308 strain, females, 49 d of age, 2.8 kg body weight at slaughter) and selected immediately after evisceration from the line of a commercial processing plant. Meat samples of about 1 cm3 were excised from bone-in muscles at 15, 60, 120, and 1,440 min postmortem, instantly frozen in liquid nitrogen and used for the determination of pH, glycolytic metabolites, buffering capacity as well as histidine dipeptides content through 1H-NMR. Overall results suggest that glycolysis in leg muscles ceased already after 2 h postmortem, whereas in breast muscle continued until 24 h, when it exhibited significantly lower pH values (P < 0.05). However, considering its remarkable glycolytic potential, pectoralis major muscle should have exhibited a greater and faster acidification, suggesting that its higher (P < 0.05) histidine dipeptides' content might have prevented a potentially stronger acidification process. Accordingly, breast muscle also showed greater (P < 0.05) buffering ability in the pH range 6.0–7.0. Therefore, anserine and carnosine, being highly positively correlated with muscle's buffering capacity (P < 0.001), might play a role in regulating postmortem pH decline, thus exerting an effect on muscle metabolism during prerigor phase and the quality of the forthcoming meat. Overall results also suggest that total histidine dipeptides content along with muscular ultimate pH represent good indicators for the energy-supplying metabolism of chicken muscles.
The elevated ultimate pH (pHu) found in Wooden Breast (WB) meat suggests an altered muscular energetic status in WB but also could be related to a prematurely terminated post-mortem pH decline. The aim of this study was to explore the factors contributing to the elevated pHu and establish whether the occurrence of WB defect alters muscle post-mortem carbohydrate metabolism and determine if the contractile apparatus reflects such changes. A total of twenty-four carcasses from Ross 308 male chickens were obtained from a commercial producer and harvested using commercial processing procedures. Carcasses were categorized into unaffected (NORM) and WB groups (n=12 each) and samples were collected from cranial bone-in Pectoralis major (PM) muscles at 15 min and 24 h post-mortem for the determination of pH, glycolytic metabolites, adenonucleotides, buffering capacity, phosphofructokinase (PFK) activity, and in vitro pH decline. Twenty-four additional deboned PM samples (12 NORM and 12 WB) were collected from the same processing plant to assess muscle histology and sarcomere length at four different locations throughout the PM muscle. Data show that the reduced glycolytic potential of WB muscles only partially explains the higher (P<0.001) pHu of WB meat, as residual glycogen along with unaltered PFK activity suggest that neither glycogen nor a deficiency of PFK are responsible for arresting glycolysis prematurely. The dramatic reduction in ATP concentrations in the early post-mortem period suggests a defective ATP-generating pathway that might be responsible for the reduced pH decline in WB samples. Further, the addition of excess of ATPase extended post-mortem glycolysis of WB meat in an in vitro glycolytic system. WB-affected samples have longer (P<0.001) sarcomeres compared to NORM, indicating that the existence of compromised energy-generating pathways in myopathic muscles that may have had consequences on the muscle contraction and tension development, as in vivo, also during the post-mortem period. Considering the overall reduced glycolytic potential and the myodegenerative processes associated with WB condition, we speculate that the higher pHu of WB meat might be the outcome of a drastically impaired energy-generating pathway combined with a deficiency and/or a dysfunction of muscle ATPases, having consequences also on muscle fibers contraction degree.
