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PSE
Livestock Production Science, 7 (1980) 303--304
303
Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
Guest Editorial PSE
W. SYBESMA
L V.O. "Schoonoord", Zeist (The Netherlands)
Pale, Soft and Exudative meat has long been a defect in pork quality, especially in areas where pig breeding has developed to a rather high quality level. Apparently the selection for more meat has interfered with post-mortem muscle metabolism. Not only fresh meat qu_ality (appearance, appreciation by the consumer), but also the technological properties have required special attention. Many investigations in Europe and the U.S.A. have centered on this problem. Seminars in The Netherlands as early as 1968 and 1971 at Zeist and in 1976 at Wageningen, in the U.S.A. in 1972 at Madison and in Denmark in 1977 at Hindsgavl Castle dealt mainly with PSE and related aspects of pork quality. Beside the problem of the meat quality, it became increasingly apparent that the physiological condition of the animal was a determining factor. Especially heat, emotional excitement, anoxia, and exhaustion were held to be partly responsible not only for the presence of PSE, but also for quite substantial losses. The incidence of transport deaths in The Netherlands increased to 0.7% in 1970. Improved environmental conditions, in particular just before and during transport, but also in the slaughter-house, were able to alleviate the condition. A further important breakthrough was the discovery of genetic factors related to the aberration. In this issue quite different approaches are described, ranging from selection on meat colour after slaughter to selection on the halothane reaction of the piglet at 6 weeks of age. Improvements not only in the meat quality, but also in diminishing losses during the whole production process are reported. From these findings, too, strong evidence emergesthat the so-called modern stress susceptible meaty pigs produce non-acceptable meat. Porcine Stress Syndrome (PSS), Malignant Hyperthermia Syndrome (MHS), and Pale, Soft and Exudative (PSE) meat are all members of the same family. This issue of the journal deals in detail with testing methods on this socalled PSE syndrome in pigs and the mechanisms behind it. These tests are used for the improvement of pig production, economically and qualitatively. These publications originate mainly from papers presented at the Harrogate E.A.A.P. Annual Meeting in 1979. It is argued here again that the PSE problem is a side effect which arose in connection with selection for a better carcass and better food conversion. Lower fat deposition would be the expression of a more 0301--6226/80/0000--0000/$02.25 © 1980 Elsevier Scientific Publishing Company
304
katabolic metabolism in which a higher lipolytic rate of the fat tissue coincides with a predisposition towards a higher glycolytic rate in the muscle tissue. It seems to be logical that if PSE is the correlated response to selection, genetic factors will be involved which might also be used in solving this problem as stated before. In the articles a different approach towards the solution of the problem is presented. The results of the different lines of research provide quite a clear picture of the underlying mechanisms, and factors like the following emerge. (1) Aberrant mitochondrial function in the muscle seems to trigger the muscle stiffening seen during the halothane reaction. After slaughter a rapid muscle rigor results from this mitochondrial dysfunction. (2) The level of CPK values in blood samples taken after a certain amount of stress is related to the reaction of the muscle tissue to certain stimuli, b u t is also higher in PSE-prone pigs. (3) The H blood group system is related to meat colour because of the close linkage with the loci of the glycogen metabolic enzymes in one chromosome. As is known, the glycolytic rate post slaughter,determines the colour of the meat, especially in the PSE syndrome. (4) The pale meat colour is of course one of the indicators of PSE meat. All the factors specified can be used in a selection program. It is unique in animal breeding that simple tests like the halothane test are capable of detecting a predisposition (to PSE meat) even in the early life of the pig. Here it has been shown that testing with this method in different countries has the benefit of producing many comparable data in a short time. The CPK test also seems to be quite promising. The more laborious mitochondrial test on Ca efflux rate can be useful as a reference method. Furthermore, the colour of the meat expressed in the so-called KK index has been proved to be an effective selection parameter in Denmark. All the work presented here shows that the research in this field in Europe is quite promising. This research seems to be on its way -- partly due to very good co-operation and good interplay of critical researchers -- to the final solution of the PSE problem, i.e. a further improvement of pork production.
303
Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands
Guest Editorial PSE
W. SYBESMA
L V.O. "Schoonoord", Zeist (The Netherlands)
Pale, Soft and Exudative meat has long been a defect in pork quality, especially in areas where pig breeding has developed to a rather high quality level. Apparently the selection for more meat has interfered with post-mortem muscle metabolism. Not only fresh meat qu_ality (appearance, appreciation by the consumer), but also the technological properties have required special attention. Many investigations in Europe and the U.S.A. have centered on this problem. Seminars in The Netherlands as early as 1968 and 1971 at Zeist and in 1976 at Wageningen, in the U.S.A. in 1972 at Madison and in Denmark in 1977 at Hindsgavl Castle dealt mainly with PSE and related aspects of pork quality. Beside the problem of the meat quality, it became increasingly apparent that the physiological condition of the animal was a determining factor. Especially heat, emotional excitement, anoxia, and exhaustion were held to be partly responsible not only for the presence of PSE, but also for quite substantial losses. The incidence of transport deaths in The Netherlands increased to 0.7% in 1970. Improved environmental conditions, in particular just before and during transport, but also in the slaughter-house, were able to alleviate the condition. A further important breakthrough was the discovery of genetic factors related to the aberration. In this issue quite different approaches are described, ranging from selection on meat colour after slaughter to selection on the halothane reaction of the piglet at 6 weeks of age. Improvements not only in the meat quality, but also in diminishing losses during the whole production process are reported. From these findings, too, strong evidence emergesthat the so-called modern stress susceptible meaty pigs produce non-acceptable meat. Porcine Stress Syndrome (PSS), Malignant Hyperthermia Syndrome (MHS), and Pale, Soft and Exudative (PSE) meat are all members of the same family. This issue of the journal deals in detail with testing methods on this socalled PSE syndrome in pigs and the mechanisms behind it. These tests are used for the improvement of pig production, economically and qualitatively. These publications originate mainly from papers presented at the Harrogate E.A.A.P. Annual Meeting in 1979. It is argued here again that the PSE problem is a side effect which arose in connection with selection for a better carcass and better food conversion. Lower fat deposition would be the expression of a more 0301--6226/80/0000--0000/$02.25 © 1980 Elsevier Scientific Publishing Company
304
katabolic metabolism in which a higher lipolytic rate of the fat tissue coincides with a predisposition towards a higher glycolytic rate in the muscle tissue. It seems to be logical that if PSE is the correlated response to selection, genetic factors will be involved which might also be used in solving this problem as stated before. In the articles a different approach towards the solution of the problem is presented. The results of the different lines of research provide quite a clear picture of the underlying mechanisms, and factors like the following emerge. (1) Aberrant mitochondrial function in the muscle seems to trigger the muscle stiffening seen during the halothane reaction. After slaughter a rapid muscle rigor results from this mitochondrial dysfunction. (2) The level of CPK values in blood samples taken after a certain amount of stress is related to the reaction of the muscle tissue to certain stimuli, b u t is also higher in PSE-prone pigs. (3) The H blood group system is related to meat colour because of the close linkage with the loci of the glycogen metabolic enzymes in one chromosome. As is known, the glycolytic rate post slaughter,determines the colour of the meat, especially in the PSE syndrome. (4) The pale meat colour is of course one of the indicators of PSE meat. All the factors specified can be used in a selection program. It is unique in animal breeding that simple tests like the halothane test are capable of detecting a predisposition (to PSE meat) even in the early life of the pig. Here it has been shown that testing with this method in different countries has the benefit of producing many comparable data in a short time. The CPK test also seems to be quite promising. The more laborious mitochondrial test on Ca efflux rate can be useful as a reference method. Furthermore, the colour of the meat expressed in the so-called KK index has been proved to be an effective selection parameter in Denmark. All the work presented here shows that the research in this field in Europe is quite promising. This research seems to be on its way -- partly due to very good co-operation and good interplay of critical researchers -- to the final solution of the PSE problem, i.e. a further improvement of pork production.