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Early Expression of Hereditary Deep Pectoral Myopathy in Turkeys Due to Forced Wing Exercise1
Early Expression of Hereditary Deep Pectoral Myopathy in Turkeys Due to Forced Wing Exercise1 J. A. HARPER, P. E. BERNIER, and L. L. THOMPSON-COWLEY Department of Poultry Science, Oregon State University, Corvallis, Oregon 97331 (Received for publication February 16, 1982)
1983 Poultry Science 62:2303-2308 INTRODUCTION Myopathy affecting the deep pectoral (supracoracoideus) muscle of turkeys was first reported by Dickinson et al. (1968). Harper et al. (1975) in later studies provided evidence indicating the defect is inherited as a polygenic recessive trait involving modifiers. Breeding age turkeys are mainly affected with a higher incidence in females than males. Muscle damage from localized hemorrhages led to the hypothesis that selection for increased muscle size in the modern turkey may have altered the vascular structure in relation to the muscle or skeleton to affect blood flow to the deep pectoral. The research mentioned, as well as that by Page and Fletcher (1975), reported a similar deep pectoral myopathy (DPM) in broiler-breeder chickens, thus lending further support to the belief that genetic selection for size and breast width is a factor in the origin of DPM. Pathological reports on DPM by Orr and Riddell (1977), Siller and Wight (1978), and Henrichs et al. (1979) clearly describe the salient focal ischemic features of the defect. These papers also discuss various aspects of environment and induced stress-causing factors in the development of DPM. Siller (1980)
1
Technical Paper No. 6245, Oregon Agricultural Experiment Station.
summarized recent investigations at the Poultry Research Center in Edinburgh and the discovery by Martindale et al. (1979) and Siller et al. (1979) that the exercised-stimulated deep pectoral muscle of heavy-type fowl increases in pressure within the fascial compartment by one-fifth more than in light-type birds. Increased pressure obstructs blood flow and results in strangulation ischemia and necrosis. Richardson et al. (1980) reported that 7-weekold broilers subjected to handling stress had a 5% incidence of DPM. Orr and Riddell (1977) and Siller et al. (1979) compared the defect to anterior tibial syndrome or "march gangrene" in man (Carter et al, 1949), which can be relieved by fasciotomy (Blandy and Fuller, 1957). Siller et al. (1979) devised a technique for slitting the fascia of the deep pectoral muscle on one side of the keel of experimental birds; then, following forced wing exercise (FWE), they showed that no ischemia occurred on the operated side, because pressure was relieved, whereas, in contrast, the muscle on the opposite side showed the typical DPM lesion. In genetically susceptible stock the late expression of the defect presents a selection problem to breeders. Attempts to find enzyme differences to identify carriers have been reported by Hollands et al. (1980, 1981) and Thompson-Cowley (1981). Other physiological measurements such as blood pressure (Thompson-Cowley, 1978) or biochemical cktermina-
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ABSTRACT In a deep pectoral myopathy selected (DPMS) line, forced wing exercise (FWE) at 20 weeks of age resulted in the same level of expressed deep pectoral myopathy (DPM) as seen in unexercised DPMS turkeys by 72 weeks of age. The FWE at 15 and 17 weeks of age in DPMS line females increased the incidence of DPM to 30 and 50% compared to 5% in unexercised controls. There is an apparent developmental age X exercise relationship in the expression of DPM. In varieties, lines, and crosses without a history of DPM, FWE does not induce the myopathy. Additional evidence confirms the modifier effect in the polygenic DPM defect. Body weight and breast width measurements in genetically susceptible turkeys were not closely or consistently associated with expression of the myopathy. The results suggest FWE of turkeys at 20 weeks of age or later as a method for detecting genetic carriers at prebreeding ages. (Key words: turkeys, myopathy, stress, body size, selection)
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HARPER ET AL.
MATERIALS AND METHODS
Deep Pectoral Myopathy Selected Line Turkeys. The DPMS line originated from two Medium White (MW) lines at the Oregon Agricultural Experiment Station (OAES) that were combined in 1970 (Harper et al, 1975), closely inbred, and selected over 11 years for increased incidence of the defect. During this period the incidence increased from 0 (males) and 2.5% (females) to 80% in males and 90% in females (Harper et al., 1981). Parental pedigreed stock were selected each year from early hatches and were about 40 weeks of age when provided artificial light on January 1. Because mean age in detecting the defect in the DPMS line is 48 ± 2 weeks, this late breeding age aided in selecting parents with the myopathy. Detection of Deep Pectoral Myopathy. The DPM was detected by breast palpation of the live bird. The accuracy of this method was previously determined on old toms and hens. In this previous study 40 old toms were examined for DPM at the Oregon Turkey Growers processing plant by slashing breasts of carcasses; of these, 17 were confirmed with the defect as compared to 18 by palpation at the OAES prior to shipping. Similarly, of 56 old hens slaughtered, there was complete agreement from observations at the OAES and the processing plant report showing 41 with DPM and 15 without. The error in detection by palpation versus breast slashing is approximately 1%.
Poults were brooded to 8 weeks of age in confinement, subsequently range reared, and then confined in groups of 10 in 3 X 3 m pens of a wire-sided pole house to 58 to 60 wks of age. Turkeys with undiagnosed DPM at this age were retained for observation up to 72 weeks of age. Turkeys were routinely weighed five or six times from 8 to 60 weeks of age and handled also at regular intervals for insemination. Rations were supplied to meet known nutritional requirements of the turkeys at varying ages and were similar for all birds most years. Forced Wing Exercise and Aspirin. Young turkeys of the DPMS line, used for determining effects of FWE and aspirin, were brooded together to 8 weeks. They were retained in brooding pens and half of the birds received supplementary aspirin at .4 g/kg in the grower ration until 28 weeks of age. At 20 weeks of age the turkeys were subdivided further, half with FWE and half without exercise treatments and either with or without aspirin. The exercise consisted of holding birds by the hocks and tilting them backwards, causing the wings to flap in an attempt to regain balance (Siller et al, 1979). Wing flaps were recorded for two 60-sec periods 1 hr apart or until wing movement ceased. Turkeys were examined by palpation to determine presence of DPM at 20, 24, and 28 weeks of age. Siller (1980) has illustrated the rapid and marked necrotic progress of DPM following FWE. Forced Wing Exercise in Variety Crosses. White and bronze poults from the same dam were obtained with semen from three Broad Breasted Bronze (BBB) lines, one with and two without a low-level DPM history, pooled with semen from DPMS line males to inseminate DPMS line females. The poults were brooded and reared together to 20 weeks of age, then divided into treatments with and without FWE. Body weight and breast width were measured at 20 and 24 weeks of age and pectoral muscles were palpated for atrophy. Forced Wing Exercise and Age. To determine exercise-induced DPM-age relationship, groups of 15- and 17-week-old DPMS line females were divided into forced exercise and unexercised groups. The experiment also included 17-weekold MW line females similarly treated. Data were obtained on body weight and breast width at 15 and 17 weeks of age, and the incidence of myopathy was recorded 4 weeks later. Forced Wing Exercise in Turkeys from Several Sources. Wild (W) (Merriam's), Large
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tion of lipoproteins in blood and fatty acids of erythrocyte membranes (Thompson-Cowley, 1981, 1982a), as well as the effects of exercise on enzyme analysis (Thompson-Cowley, 1981, 1982b), all provide limitations for identifying carriers. Since the research of Siller et al (1978/1979) demonstrated that DPM is a muscle compartment exercise-pressure related syndrome, it was possible with genetic stocks available at this station to clarify further the role of anatomy. Within a deep pectoral myopathy selected (DPMS) line, it was also possible to ascertain if aspirin, which has been implicated in reducing strokes in humans due to transient ischemia, might also have some effect on the incidence of DPM. This paper provides observations on the effect of FWE at different ages on expression of DPM; effect of aspirin; and comparison of varieties, lines, and crosses of turkeys with and without FWE.
DEEP PECTORAL MYOPATHY IN TURKEYS
RESULTS AND DISCUSSION Deep Pectoral Myopathy, Aspirin, and Forced Wing Exercise. At 20 weeks of age, none of the turkeys showed DPM upon palpa-
tion. When 24 and 28 weeks of age, young turkey hens of the DPMS line without FWE showed no marked difference in incidence of the defect, whether with or without dietary aspirin (Table 1). With FWE at 20 weeks of age the incidence of DPM observed at 24 and 28 weeks was 69.4 and 74.2% compared with 12.7 and 29.1% for turkeys without FWE. Exercised males receiving aspirin showed an incidence of 33.3% (5/15) of DPM at 24 weeks of age and those without aspirin 66.7% (10/15), while in the exercised females the trend in incidence of DPM was similar, although higher than for males. The incidence in exercised males receiving aspirin increased from 3 3.3 to 53.3% (8/15) between 24 and 28 weeks of age, while the incidence in the other three treatments remained at the same level after 24 weeks. From these limited data no conclusion can be reached as to the effect of aspirin on DPM. The Chi-square analyses of the data showed that significant differences (P<.05) (FWE-M, X = 26.47; M, X = 6.59; F, X = 19.95) were associated mainly with FWE.
TABLE 1. Effect of forced wing exercise (FWE) and dietary aspirin on incidence of deep pectoral (DPM) Treatment FWE1
Aspirin 2
Sex
DPM selected line, t u r k e y s
Incidence of DPM, age 24 wk
20 wk /
0 0
myopathy
1
28 wk
,, _
19 15
0 0
2 3
6 5
34
0
5
11
22 23
0 0
3 2
5 7
Total
45
0
5
12
Total and p e r c e n t
79
0
10(12.7%)
23 (29.1%)
15 15
0 0
10 14
10 14
30
0
24
24
15 17
0 0
5 14
8 14
Total
32
0
19
22
Total and p e r c e n t
62
0
4 3 (69.4%)
4 6 (74.2%)
0 0
M F
Total + +
0 0
+ +
0 0
M F
M F
Total + +
+
+
M F
Forced wing exercise at 20 weeks of age: two oO-sec wing-flap periods 1 hr part or until wing flaps ceased. Mean: 47.5 ± 3.4 sec, 59.7 ± 8.2 flaps. 2
Dietary level of .40 g/kg feed.
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White (LW), and MW from station stock were brooded and reared in similar environments to 20 weeks of age when stressed or not stressed by FWE. The MW line, introduced in 1973, was used in a selection study for semen traits and was also from the same strain source used in some of the original DPMS matings. Close inbreeding was avoided in subsequent MW line matings by following a pen rotational system. A DPM varying between 1.5 and 3% was observed in the MW line during the last six generations. The myopathy was also known to be present in the LW line. The LW male used within the LW line also served as the semen source for a cross made with Black (B) variety females. The B stock had been maintained for over 30 years without any evidence of DPM. Body weight was recorded at 8, 24, 28, and 32 weeks of age.
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HARPER ET AL.
TABLE 2. Effect of forced wing exercise (FWE) on incidence of deep pectoral myopathy in 20^week-old deep pectoral myopathy selected (DPMS) line and variety crosses of turkeys FWE exercise
Line1
0 0
DPMS DPMS
6 5
M F
+ +
DPMS DPMS
16 17
M F
39.4 + 7.4 39.4 ±6.3
+ +
BBB X DPMS BBBX DPMS
16 16
M F
48.6 ± 7.0 38.3 + 9.3
Turkeys (no .)
(sex)
Time
Flaps
(sec)
(no.)
Body weight, 20 wk
Breast width, 20 wk
Incidence of DPM, 24 wk
(kg)
(cm)
(%)
6.32 ± .37 4.49 ± .45
9.85 ± 1.47 10.31 ± .82
16.7 0
68.2 ± 9.9 67.9 ± 16.6
6.1- ± 1.2 4.0 ± .3
10.0 ± 2.9 9.0 ± 2.6
81.2 88.2
78.5 ± 20.0 68.2 + 15.3
8.3 ± 1.1 5.60 ± .5
11.3 ± 1.6 11.9 ± .80
0 6.2
See Table 1, footnote 1.
Forced Wing Exercise Within Line and Variety Crosses. Data in Table 2 show that at 24 weeks of age one of 16 exercised BBB x DPMS female progeny was myopathic, while all 16 FWE males were normal. By comparison, 16 DPMS exercised males and 17 DPMS females had an incidence of 81.2 and 88.2% myopathy. One of 11 unexercised DPMS line turkeys was observed with the defect. These and other observations (Harper et ah, 1975) indicate that progeny of DPM-free and DPMS line crosses do not exhibit the defect when stressed. Breast width was greater in BBB x DPMS progeny, and this suggests that breast muscle size is not the primary factor initiating DPM. Age and Forced Wing Exercise Effect. When 15- and 17-week-old DPMS line female turkeys
were exercised, they showed a lower myopathy incidence (Table 3) than previously observed with exercise at 20 weeks of age. The MW line females with and without exercise did not express DPM. Levels of 30 and 50% were observed at 19 and 21 weeks of age in the exercised DPMS line birds compared to 5% in the 19-week-old DPMS females without FWE. This suggests an age and development relationship associated with time of DPM expression. Breast width comparisons again showed this measurement as unrelated to the expression of DPM. Forced Wing Exercise in Turkeys from Several Sources. Results from FWE trials using different genetic sources of young turkeys showed W turkeys were free of DPM with or without exercise. One of 30 exercised MW line
TABLE 3. Effect of forced wing exercise on incidence of deep pectoral myopathy (DPM) in 15- and 11'-week-old control and DPMS line turkey females FWE 2 1
Treatment
Line
0 + 0 + +
DPMS DPMS MW MW DPMS
Age
Time
Flaps
Body weight
Breast width
Age
Incidence of DPM
(wk)
(sec)
(no.)
(kg)
(cm)
(wk)
(%)
7.9 7.5 8.7 8.7 9.4
19 19 21 21 21
5 30 0 0 50.0
15 15 17 17 17
42 ± 9.9
72 ± 24
48 ± 8.0 46 ± 8.6
83 ± 13.4 72 ± 13.7
2.0 1.9 3.0 2.9 3.1
± .4 ±.3 ± .5 ± .5 ±.4
± .7 ± .8 ±.5 ± .8 ± .7
1
Twenty females each deep pectoral myopathy selected (DPMS) and Medium White (MW) lines.
2
See Table 1, footnote 1.
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'BBB, Broad Breasted Bronze variety. 2
DEEP PECTORAL MYOPATHY IN TURKEYS
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TABLE 4. Body weight and conformation measurements of several lines of turkeys at 32 weeks of age Body Line 1
Year
Sex
Turkeys
weight
(no.)
(kg)
Breast width
(CITiy
40 24
1971 1981
F F
120 40
1975 1981
M M
40 40
1975 1981
F F
200 200
6.1 ± 6.3 ±
W
1981
M F
16 43
7.0 ± 4.8 ±
LW
1981
M F
4 9
17.5 ± 1.9 10.3 ± 1.2
LWX B
1981
M F
4 9
14.4 ± 1.3 8.9 ± 1.2
1
12.0 ± 1.6 11.5 ± .7
12.9 ± 1.6 12.9 + 1.6
17.8 ± 17.3 ±
.8 .6
16.8 ± 16.8 +
.9 .5
.3 .4
11.9 + 1.1 12.7 ± 1.0
14.7 ± 1.4 14.7 ± .5
13.5 ± 12.9+
.4 .4
11.2 ± 2.0 11.4 ± .7
13.7 ± 1.4 15.4 + 1.0
17.5 ± 2.7 17.6 ± .7
16.5 ± 1.9 16.2 + .4
.6 .6
13.1 + 13.2 ±
.9 .9
15.0 + 1.0 14.8 ± 1.1
12.9 + 1.3 13.3 + .5
.9 .5
7.2 ± 7.9 ±
.7 .9
17.1 ± 15.2 ±
.7 .5
18.7 ± 14.6 +
.7 .5
19.2 ± .7 18.0 + 1.2
20.9 ± 1.2 17.6 ± .9
19.4"+. 15.5 ±
.9 .5
11.4 + 1.6 14.2 + 1.0
21.1 ± 1.0 16.4 ± .9
20.2 ± 15.0 ±
.3 .8
5.8 ± 5.8 ±
DPMS, Deep pectoral myopathy selected; MW, Medium White: W, Wild; LW, Large White; and B, Black.
females developed DPM. This is close t o t h e level found for this line in prior generations. N o n e of t h e MW and LW line females w i t h o u t FWE were m y o p a t h i c ; however, 4 of 10 LW exercised birds developed t h e defect. Progeny from t h e LW X B did n o t show DPM w h e t h e r exercised or not. In a n o t h e r e x p e r i m e n t t h a t c o m p a r e d t h e DPMS X B cross, an incidence of 4 of 10 occurred by 52 weeks of age in t h e p u r e line and n o n e in a similar n u m b e r of cross progeny. Data in Table 4 s h o w t h a t b o d y weight and c o n f o r m a t i o n at 32 weeks of age changed very little in t h e DPMS line during 11 years. This was also observed for t h e MW line during six generations. T h e W t u r k e y s were lower in b o d y weight and smaller in breast width t h a n t h e o t h e r lines, b u t in p r o p o r t i o n t o b o d y size t h e y had m u c h longer keels and shanks. In contrast, t h e LW line had t h e largest b o d y size and breast w i d t h w h e n c o m p a r e d t o o t h e r lines, while t h e LW X B cross were intermediate t o domestic lines. Because t h e MW line t u r k e y s had a wider breast t h a n t h e DPMS line b u t showed only a low incidence of t h e defect, either with or w i t h o u t FWE, it is a p p a r e n t t h a t specific factors o t h e r t h a n breast width are involved w i t h t h e incidence of deep pectoral m y o p a t h y . If only breast w i d t h or size was t h e
primary cause, it w o u l d be e x p e c t e d t h a t all- wide-breasted t u r k e y s would develop t h e m y o p a t h y w h e n maintained u n d e r similar e n v i r o n m e n t and m a n a g e m e n t c o n d i t i o n s . Present d a t a indicate t h a t this is n o t t h e case a n d suggest further research is required t o define w h a t a n a t o m i c a l and physiological factors are involved. T h e expression of DPM in response t o FWE (Siller et al, 1979) within different g e n o t y p e s suggests FWE as a m e t h o d for early-age screening of t u r k e y breeding stock. REFERENCES Blandy, J. P., and R. Fuller, 1957. March gangrene. Ischaemic myositis of the leg muscles from exercise. J. Bone Jt. Surg. Br. Vol. 39B:679-693. Carter, A. B., R. L. Richards, and R. B. Zachary, 1949. The anterior tibial syndrome. Lancet 2:928-934. Dickinson, E. M., J. O. Stephens, and D. H. Heifer, 1968. A degenerative myopathy in turkeys. Page 7 in Proc. 17th Western Poultry Dis. Conf., Davis, CA. Harper, J. A., P. E. Bernier, D. H. Heifer, and J. A. Schmitz, 1975. Degenerative myopathy of the deep pectoral muscle in the turkey. J. Hered. 66:362-366. Harper, J. A., P. E. Bernier, and L. L. ThompsonCowley, 1981. Incidence of deep pectoral myopathy in turkeys due to breeding and altered expresion from forced exercise. Poultry Sci. 60:1776. (Abstr.)
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M M
MW
Shank length
,
1971 1981
DPMS
keel length
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HARPER ET AL. 24:1054-1059. Siller, W. G., 1980. Recent developments concerning Oregon disease. Turkeys 28:47—53. Siller, W. G., L. Martindale, and P.A.L. Wight, 1979. The prevention of experimental deep pectoral myopathy of the fowl by fasciotomy. Avian Pathol. 8:301-307. Siller, W. G„ and P.A.L. Wight, 1978. The pathology of deep pectoral myopathy of turkeys. Avian Pathol. 7:583-618. Siller, W. G., P.A.L. Wight, and L. Martindale. 1978/ 1979. Exercise-induced deep pectoral myopathy in broiler fowls and turkeys. Vet. Sci. Comm. 2:331-336. Thompson-Cowley, L., 1978. Blood pressure in turkeys afflicted with degenerative muscle disease. Proc. Oregon Acad. Sci. 14:35—36. Thompson-Cowley, L., 1981. Hemophysiology in the pathogenesis of deep pectoral myopathy in the turkey. Ph.D. thesis, Oregon State Univ., Corvallis, OR. Thompson-Cowley, L. L., M. J. Tripp, and J. A. Harper, 1982a. Turkey erythrocyte membrane fatty acids. Poultry Sci. 61:1555-1556. (Abstr.) Thompson-Cowley, L. L., M. J. Tripp, and J. A. Harper, 1982b. Enzyme levels and clearance times in relation to exercise and onset of Deep Pectoral Myopathy. Pages 24—26 in Proc. 31st Western Poultry Dis. Conf., Davis, CA.
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 13, 2015
Henrichs, K. J., J. M. Jones, C. L. Berry, and M. Swash, 1979. Pathogenesis of ischaemic pectoral myopathy in the domestic turkey. Br. Vet. J. 135:286-290. Hollands,' K. G., A. A. Grander, and J. S. Gavora, 1981. Induction by exercise of deep pectoral myopathy and associated changes in plasma creatine kinase levels in female turkeys. Poultry Sci. 60:1669. (Abstr.) Hollands, K. G., A. A. Grander, C. J. Williams, and J. S. Gavora, 1980. Plasma creatine kinase as an indicator of degenerative myopathy in live turkeys. Br. Poult. Sci. 21:161-170. Martindale, L., W. G. Siller, and P.A.L. Wight, 1979. Effects of subfascial pressure in experimental deep pectoral myopathy of the fowl. Avian Pathol. 8:425-436. Orr, J. P., and C. Riddell, 1977. Investigation of the vascular supply of the pectoral muscles of the domestic turkey and comparison of experimentally produced infarcts with naturally occurring deep pectoral myopathy. Am. J. Vet. Res. 38:1237-1242. Page, R. K., and O. J. Fletcher, 1975. Myopathy of the deep pectoral muscle in broiler breeder hens. Avian Dis. 19:814-821. Richardson, J. A., J. Burgener, R. W. Winterfield, and A. S. Dhillon, 1980. Deep pectoral myopathy in seven-week-old broiler chickens. Avian Dis.
1983 Poultry Science 62:2303-2308 INTRODUCTION Myopathy affecting the deep pectoral (supracoracoideus) muscle of turkeys was first reported by Dickinson et al. (1968). Harper et al. (1975) in later studies provided evidence indicating the defect is inherited as a polygenic recessive trait involving modifiers. Breeding age turkeys are mainly affected with a higher incidence in females than males. Muscle damage from localized hemorrhages led to the hypothesis that selection for increased muscle size in the modern turkey may have altered the vascular structure in relation to the muscle or skeleton to affect blood flow to the deep pectoral. The research mentioned, as well as that by Page and Fletcher (1975), reported a similar deep pectoral myopathy (DPM) in broiler-breeder chickens, thus lending further support to the belief that genetic selection for size and breast width is a factor in the origin of DPM. Pathological reports on DPM by Orr and Riddell (1977), Siller and Wight (1978), and Henrichs et al. (1979) clearly describe the salient focal ischemic features of the defect. These papers also discuss various aspects of environment and induced stress-causing factors in the development of DPM. Siller (1980)
1
Technical Paper No. 6245, Oregon Agricultural Experiment Station.
summarized recent investigations at the Poultry Research Center in Edinburgh and the discovery by Martindale et al. (1979) and Siller et al. (1979) that the exercised-stimulated deep pectoral muscle of heavy-type fowl increases in pressure within the fascial compartment by one-fifth more than in light-type birds. Increased pressure obstructs blood flow and results in strangulation ischemia and necrosis. Richardson et al. (1980) reported that 7-weekold broilers subjected to handling stress had a 5% incidence of DPM. Orr and Riddell (1977) and Siller et al. (1979) compared the defect to anterior tibial syndrome or "march gangrene" in man (Carter et al, 1949), which can be relieved by fasciotomy (Blandy and Fuller, 1957). Siller et al. (1979) devised a technique for slitting the fascia of the deep pectoral muscle on one side of the keel of experimental birds; then, following forced wing exercise (FWE), they showed that no ischemia occurred on the operated side, because pressure was relieved, whereas, in contrast, the muscle on the opposite side showed the typical DPM lesion. In genetically susceptible stock the late expression of the defect presents a selection problem to breeders. Attempts to find enzyme differences to identify carriers have been reported by Hollands et al. (1980, 1981) and Thompson-Cowley (1981). Other physiological measurements such as blood pressure (Thompson-Cowley, 1978) or biochemical cktermina-
2303
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 13, 2015
ABSTRACT In a deep pectoral myopathy selected (DPMS) line, forced wing exercise (FWE) at 20 weeks of age resulted in the same level of expressed deep pectoral myopathy (DPM) as seen in unexercised DPMS turkeys by 72 weeks of age. The FWE at 15 and 17 weeks of age in DPMS line females increased the incidence of DPM to 30 and 50% compared to 5% in unexercised controls. There is an apparent developmental age X exercise relationship in the expression of DPM. In varieties, lines, and crosses without a history of DPM, FWE does not induce the myopathy. Additional evidence confirms the modifier effect in the polygenic DPM defect. Body weight and breast width measurements in genetically susceptible turkeys were not closely or consistently associated with expression of the myopathy. The results suggest FWE of turkeys at 20 weeks of age or later as a method for detecting genetic carriers at prebreeding ages. (Key words: turkeys, myopathy, stress, body size, selection)
2304
HARPER ET AL.
MATERIALS AND METHODS
Deep Pectoral Myopathy Selected Line Turkeys. The DPMS line originated from two Medium White (MW) lines at the Oregon Agricultural Experiment Station (OAES) that were combined in 1970 (Harper et al, 1975), closely inbred, and selected over 11 years for increased incidence of the defect. During this period the incidence increased from 0 (males) and 2.5% (females) to 80% in males and 90% in females (Harper et al., 1981). Parental pedigreed stock were selected each year from early hatches and were about 40 weeks of age when provided artificial light on January 1. Because mean age in detecting the defect in the DPMS line is 48 ± 2 weeks, this late breeding age aided in selecting parents with the myopathy. Detection of Deep Pectoral Myopathy. The DPM was detected by breast palpation of the live bird. The accuracy of this method was previously determined on old toms and hens. In this previous study 40 old toms were examined for DPM at the Oregon Turkey Growers processing plant by slashing breasts of carcasses; of these, 17 were confirmed with the defect as compared to 18 by palpation at the OAES prior to shipping. Similarly, of 56 old hens slaughtered, there was complete agreement from observations at the OAES and the processing plant report showing 41 with DPM and 15 without. The error in detection by palpation versus breast slashing is approximately 1%.
Poults were brooded to 8 weeks of age in confinement, subsequently range reared, and then confined in groups of 10 in 3 X 3 m pens of a wire-sided pole house to 58 to 60 wks of age. Turkeys with undiagnosed DPM at this age were retained for observation up to 72 weeks of age. Turkeys were routinely weighed five or six times from 8 to 60 weeks of age and handled also at regular intervals for insemination. Rations were supplied to meet known nutritional requirements of the turkeys at varying ages and were similar for all birds most years. Forced Wing Exercise and Aspirin. Young turkeys of the DPMS line, used for determining effects of FWE and aspirin, were brooded together to 8 weeks. They were retained in brooding pens and half of the birds received supplementary aspirin at .4 g/kg in the grower ration until 28 weeks of age. At 20 weeks of age the turkeys were subdivided further, half with FWE and half without exercise treatments and either with or without aspirin. The exercise consisted of holding birds by the hocks and tilting them backwards, causing the wings to flap in an attempt to regain balance (Siller et al, 1979). Wing flaps were recorded for two 60-sec periods 1 hr apart or until wing movement ceased. Turkeys were examined by palpation to determine presence of DPM at 20, 24, and 28 weeks of age. Siller (1980) has illustrated the rapid and marked necrotic progress of DPM following FWE. Forced Wing Exercise in Variety Crosses. White and bronze poults from the same dam were obtained with semen from three Broad Breasted Bronze (BBB) lines, one with and two without a low-level DPM history, pooled with semen from DPMS line males to inseminate DPMS line females. The poults were brooded and reared together to 20 weeks of age, then divided into treatments with and without FWE. Body weight and breast width were measured at 20 and 24 weeks of age and pectoral muscles were palpated for atrophy. Forced Wing Exercise and Age. To determine exercise-induced DPM-age relationship, groups of 15- and 17-week-old DPMS line females were divided into forced exercise and unexercised groups. The experiment also included 17-weekold MW line females similarly treated. Data were obtained on body weight and breast width at 15 and 17 weeks of age, and the incidence of myopathy was recorded 4 weeks later. Forced Wing Exercise in Turkeys from Several Sources. Wild (W) (Merriam's), Large
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tion of lipoproteins in blood and fatty acids of erythrocyte membranes (Thompson-Cowley, 1981, 1982a), as well as the effects of exercise on enzyme analysis (Thompson-Cowley, 1981, 1982b), all provide limitations for identifying carriers. Since the research of Siller et al (1978/1979) demonstrated that DPM is a muscle compartment exercise-pressure related syndrome, it was possible with genetic stocks available at this station to clarify further the role of anatomy. Within a deep pectoral myopathy selected (DPMS) line, it was also possible to ascertain if aspirin, which has been implicated in reducing strokes in humans due to transient ischemia, might also have some effect on the incidence of DPM. This paper provides observations on the effect of FWE at different ages on expression of DPM; effect of aspirin; and comparison of varieties, lines, and crosses of turkeys with and without FWE.
DEEP PECTORAL MYOPATHY IN TURKEYS
RESULTS AND DISCUSSION Deep Pectoral Myopathy, Aspirin, and Forced Wing Exercise. At 20 weeks of age, none of the turkeys showed DPM upon palpa-
tion. When 24 and 28 weeks of age, young turkey hens of the DPMS line without FWE showed no marked difference in incidence of the defect, whether with or without dietary aspirin (Table 1). With FWE at 20 weeks of age the incidence of DPM observed at 24 and 28 weeks was 69.4 and 74.2% compared with 12.7 and 29.1% for turkeys without FWE. Exercised males receiving aspirin showed an incidence of 33.3% (5/15) of DPM at 24 weeks of age and those without aspirin 66.7% (10/15), while in the exercised females the trend in incidence of DPM was similar, although higher than for males. The incidence in exercised males receiving aspirin increased from 3 3.3 to 53.3% (8/15) between 24 and 28 weeks of age, while the incidence in the other three treatments remained at the same level after 24 weeks. From these limited data no conclusion can be reached as to the effect of aspirin on DPM. The Chi-square analyses of the data showed that significant differences (P<.05) (FWE-M, X = 26.47; M, X = 6.59; F, X = 19.95) were associated mainly with FWE.
TABLE 1. Effect of forced wing exercise (FWE) and dietary aspirin on incidence of deep pectoral (DPM) Treatment FWE1
Aspirin 2
Sex
DPM selected line, t u r k e y s
Incidence of DPM, age 24 wk
20 wk /
0 0
myopathy
1
28 wk
,, _
19 15
0 0
2 3
6 5
34
0
5
11
22 23
0 0
3 2
5 7
Total
45
0
5
12
Total and p e r c e n t
79
0
10(12.7%)
23 (29.1%)
15 15
0 0
10 14
10 14
30
0
24
24
15 17
0 0
5 14
8 14
Total
32
0
19
22
Total and p e r c e n t
62
0
4 3 (69.4%)
4 6 (74.2%)
0 0
M F
Total + +
0 0
+ +
0 0
M F
M F
Total + +
+
+
M F
Forced wing exercise at 20 weeks of age: two oO-sec wing-flap periods 1 hr part or until wing flaps ceased. Mean: 47.5 ± 3.4 sec, 59.7 ± 8.2 flaps. 2
Dietary level of .40 g/kg feed.
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White (LW), and MW from station stock were brooded and reared in similar environments to 20 weeks of age when stressed or not stressed by FWE. The MW line, introduced in 1973, was used in a selection study for semen traits and was also from the same strain source used in some of the original DPMS matings. Close inbreeding was avoided in subsequent MW line matings by following a pen rotational system. A DPM varying between 1.5 and 3% was observed in the MW line during the last six generations. The myopathy was also known to be present in the LW line. The LW male used within the LW line also served as the semen source for a cross made with Black (B) variety females. The B stock had been maintained for over 30 years without any evidence of DPM. Body weight was recorded at 8, 24, 28, and 32 weeks of age.
2305
2306
HARPER ET AL.
TABLE 2. Effect of forced wing exercise (FWE) on incidence of deep pectoral myopathy in 20^week-old deep pectoral myopathy selected (DPMS) line and variety crosses of turkeys FWE exercise
Line1
0 0
DPMS DPMS
6 5
M F
+ +
DPMS DPMS
16 17
M F
39.4 + 7.4 39.4 ±6.3
+ +
BBB X DPMS BBBX DPMS
16 16
M F
48.6 ± 7.0 38.3 + 9.3
Turkeys (no .)
(sex)
Time
Flaps
(sec)
(no.)
Body weight, 20 wk
Breast width, 20 wk
Incidence of DPM, 24 wk
(kg)
(cm)
(%)
6.32 ± .37 4.49 ± .45
9.85 ± 1.47 10.31 ± .82
16.7 0
68.2 ± 9.9 67.9 ± 16.6
6.1- ± 1.2 4.0 ± .3
10.0 ± 2.9 9.0 ± 2.6
81.2 88.2
78.5 ± 20.0 68.2 + 15.3
8.3 ± 1.1 5.60 ± .5
11.3 ± 1.6 11.9 ± .80
0 6.2
See Table 1, footnote 1.
Forced Wing Exercise Within Line and Variety Crosses. Data in Table 2 show that at 24 weeks of age one of 16 exercised BBB x DPMS female progeny was myopathic, while all 16 FWE males were normal. By comparison, 16 DPMS exercised males and 17 DPMS females had an incidence of 81.2 and 88.2% myopathy. One of 11 unexercised DPMS line turkeys was observed with the defect. These and other observations (Harper et ah, 1975) indicate that progeny of DPM-free and DPMS line crosses do not exhibit the defect when stressed. Breast width was greater in BBB x DPMS progeny, and this suggests that breast muscle size is not the primary factor initiating DPM. Age and Forced Wing Exercise Effect. When 15- and 17-week-old DPMS line female turkeys
were exercised, they showed a lower myopathy incidence (Table 3) than previously observed with exercise at 20 weeks of age. The MW line females with and without exercise did not express DPM. Levels of 30 and 50% were observed at 19 and 21 weeks of age in the exercised DPMS line birds compared to 5% in the 19-week-old DPMS females without FWE. This suggests an age and development relationship associated with time of DPM expression. Breast width comparisons again showed this measurement as unrelated to the expression of DPM. Forced Wing Exercise in Turkeys from Several Sources. Results from FWE trials using different genetic sources of young turkeys showed W turkeys were free of DPM with or without exercise. One of 30 exercised MW line
TABLE 3. Effect of forced wing exercise on incidence of deep pectoral myopathy (DPM) in 15- and 11'-week-old control and DPMS line turkey females FWE 2 1
Treatment
Line
0 + 0 + +
DPMS DPMS MW MW DPMS
Age
Time
Flaps
Body weight
Breast width
Age
Incidence of DPM
(wk)
(sec)
(no.)
(kg)
(cm)
(wk)
(%)
7.9 7.5 8.7 8.7 9.4
19 19 21 21 21
5 30 0 0 50.0
15 15 17 17 17
42 ± 9.9
72 ± 24
48 ± 8.0 46 ± 8.6
83 ± 13.4 72 ± 13.7
2.0 1.9 3.0 2.9 3.1
± .4 ±.3 ± .5 ± .5 ±.4
± .7 ± .8 ±.5 ± .8 ± .7
1
Twenty females each deep pectoral myopathy selected (DPMS) and Medium White (MW) lines.
2
See Table 1, footnote 1.
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'BBB, Broad Breasted Bronze variety. 2
DEEP PECTORAL MYOPATHY IN TURKEYS
2307
TABLE 4. Body weight and conformation measurements of several lines of turkeys at 32 weeks of age Body Line 1
Year
Sex
Turkeys
weight
(no.)
(kg)
Breast width
(CITiy
40 24
1971 1981
F F
120 40
1975 1981
M M
40 40
1975 1981
F F
200 200
6.1 ± 6.3 ±
W
1981
M F
16 43
7.0 ± 4.8 ±
LW
1981
M F
4 9
17.5 ± 1.9 10.3 ± 1.2
LWX B
1981
M F
4 9
14.4 ± 1.3 8.9 ± 1.2
1
12.0 ± 1.6 11.5 ± .7
12.9 ± 1.6 12.9 + 1.6
17.8 ± 17.3 ±
.8 .6
16.8 ± 16.8 +
.9 .5
.3 .4
11.9 + 1.1 12.7 ± 1.0
14.7 ± 1.4 14.7 ± .5
13.5 ± 12.9+
.4 .4
11.2 ± 2.0 11.4 ± .7
13.7 ± 1.4 15.4 + 1.0
17.5 ± 2.7 17.6 ± .7
16.5 ± 1.9 16.2 + .4
.6 .6
13.1 + 13.2 ±
.9 .9
15.0 + 1.0 14.8 ± 1.1
12.9 + 1.3 13.3 + .5
.9 .5
7.2 ± 7.9 ±
.7 .9
17.1 ± 15.2 ±
.7 .5
18.7 ± 14.6 +
.7 .5
19.2 ± .7 18.0 + 1.2
20.9 ± 1.2 17.6 ± .9
19.4"+. 15.5 ±
.9 .5
11.4 + 1.6 14.2 + 1.0
21.1 ± 1.0 16.4 ± .9
20.2 ± 15.0 ±
.3 .8
5.8 ± 5.8 ±
DPMS, Deep pectoral myopathy selected; MW, Medium White: W, Wild; LW, Large White; and B, Black.
females developed DPM. This is close t o t h e level found for this line in prior generations. N o n e of t h e MW and LW line females w i t h o u t FWE were m y o p a t h i c ; however, 4 of 10 LW exercised birds developed t h e defect. Progeny from t h e LW X B did n o t show DPM w h e t h e r exercised or not. In a n o t h e r e x p e r i m e n t t h a t c o m p a r e d t h e DPMS X B cross, an incidence of 4 of 10 occurred by 52 weeks of age in t h e p u r e line and n o n e in a similar n u m b e r of cross progeny. Data in Table 4 s h o w t h a t b o d y weight and c o n f o r m a t i o n at 32 weeks of age changed very little in t h e DPMS line during 11 years. This was also observed for t h e MW line during six generations. T h e W t u r k e y s were lower in b o d y weight and smaller in breast width t h a n t h e o t h e r lines, b u t in p r o p o r t i o n t o b o d y size t h e y had m u c h longer keels and shanks. In contrast, t h e LW line had t h e largest b o d y size and breast w i d t h w h e n c o m p a r e d t o o t h e r lines, while t h e LW X B cross were intermediate t o domestic lines. Because t h e MW line t u r k e y s had a wider breast t h a n t h e DPMS line b u t showed only a low incidence of t h e defect, either with or w i t h o u t FWE, it is a p p a r e n t t h a t specific factors o t h e r t h a n breast width are involved w i t h t h e incidence of deep pectoral m y o p a t h y . If only breast w i d t h or size was t h e
primary cause, it w o u l d be e x p e c t e d t h a t all- wide-breasted t u r k e y s would develop t h e m y o p a t h y w h e n maintained u n d e r similar e n v i r o n m e n t and m a n a g e m e n t c o n d i t i o n s . Present d a t a indicate t h a t this is n o t t h e case a n d suggest further research is required t o define w h a t a n a t o m i c a l and physiological factors are involved. T h e expression of DPM in response t o FWE (Siller et al, 1979) within different g e n o t y p e s suggests FWE as a m e t h o d for early-age screening of t u r k e y breeding stock. REFERENCES Blandy, J. P., and R. Fuller, 1957. March gangrene. Ischaemic myositis of the leg muscles from exercise. J. Bone Jt. Surg. Br. Vol. 39B:679-693. Carter, A. B., R. L. Richards, and R. B. Zachary, 1949. The anterior tibial syndrome. Lancet 2:928-934. Dickinson, E. M., J. O. Stephens, and D. H. Heifer, 1968. A degenerative myopathy in turkeys. Page 7 in Proc. 17th Western Poultry Dis. Conf., Davis, CA. Harper, J. A., P. E. Bernier, D. H. Heifer, and J. A. Schmitz, 1975. Degenerative myopathy of the deep pectoral muscle in the turkey. J. Hered. 66:362-366. Harper, J. A., P. E. Bernier, and L. L. ThompsonCowley, 1981. Incidence of deep pectoral myopathy in turkeys due to breeding and altered expresion from forced exercise. Poultry Sci. 60:1776. (Abstr.)
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M M
MW
Shank length
,
1971 1981
DPMS
keel length
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HARPER ET AL. 24:1054-1059. Siller, W. G., 1980. Recent developments concerning Oregon disease. Turkeys 28:47—53. Siller, W. G., L. Martindale, and P.A.L. Wight, 1979. The prevention of experimental deep pectoral myopathy of the fowl by fasciotomy. Avian Pathol. 8:301-307. Siller, W. G„ and P.A.L. Wight, 1978. The pathology of deep pectoral myopathy of turkeys. Avian Pathol. 7:583-618. Siller, W. G., P.A.L. Wight, and L. Martindale. 1978/ 1979. Exercise-induced deep pectoral myopathy in broiler fowls and turkeys. Vet. Sci. Comm. 2:331-336. Thompson-Cowley, L., 1978. Blood pressure in turkeys afflicted with degenerative muscle disease. Proc. Oregon Acad. Sci. 14:35—36. Thompson-Cowley, L., 1981. Hemophysiology in the pathogenesis of deep pectoral myopathy in the turkey. Ph.D. thesis, Oregon State Univ., Corvallis, OR. Thompson-Cowley, L. L., M. J. Tripp, and J. A. Harper, 1982a. Turkey erythrocyte membrane fatty acids. Poultry Sci. 61:1555-1556. (Abstr.) Thompson-Cowley, L. L., M. J. Tripp, and J. A. Harper, 1982b. Enzyme levels and clearance times in relation to exercise and onset of Deep Pectoral Myopathy. Pages 24—26 in Proc. 31st Western Poultry Dis. Conf., Davis, CA.
Downloaded from http://ps.oxfordjournals.org/ at New York University on June 13, 2015
Henrichs, K. J., J. M. Jones, C. L. Berry, and M. Swash, 1979. Pathogenesis of ischaemic pectoral myopathy in the domestic turkey. Br. Vet. J. 135:286-290. Hollands,' K. G., A. A. Grander, and J. S. Gavora, 1981. Induction by exercise of deep pectoral myopathy and associated changes in plasma creatine kinase levels in female turkeys. Poultry Sci. 60:1669. (Abstr.) Hollands, K. G., A. A. Grander, C. J. Williams, and J. S. Gavora, 1980. Plasma creatine kinase as an indicator of degenerative myopathy in live turkeys. Br. Poult. Sci. 21:161-170. Martindale, L., W. G. Siller, and P.A.L. Wight, 1979. Effects of subfascial pressure in experimental deep pectoral myopathy of the fowl. Avian Pathol. 8:425-436. Orr, J. P., and C. Riddell, 1977. Investigation of the vascular supply of the pectoral muscles of the domestic turkey and comparison of experimentally produced infarcts with naturally occurring deep pectoral myopathy. Am. J. Vet. Res. 38:1237-1242. Page, R. K., and O. J. Fletcher, 1975. Myopathy of the deep pectoral muscle in broiler breeder hens. Avian Dis. 19:814-821. Richardson, J. A., J. Burgener, R. W. Winterfield, and A. S. Dhillon, 1980. Deep pectoral myopathy in seven-week-old broiler chickens. Avian Dis.