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Effect of Selenium and Vitamin E on the Development of Immunity to Coccidiosis in Chickens1
Effect of Selenium and Vitamin E on the Development of Immunity to Coccidiosis in Chickens1 G. L. COLNAGO,2 L. S. JENSEN, 3 and P. L. LONG Department of Poultry Science, University of Georgia, Athens, Georgia 30602 (Received for publication August 23, 1983)
1984 Poultry Science 63:1136-1143 INTRODUCTION
The vertebrates have basically two lines of defense against infectant microorganisms. These consist of specific or immune response (humoral and cellular) and a nonspecific system, which provides broad, generalized types of protection not directed specifically against microorganisms. The nutritional status of an animal has a significant effect on host defense mechanisms. Selenium (Se) and vitamin E have been shown to play a major role in the development and maintenance of the defense systems (Tengerdy et al, 1973; Spallholz et al, 1973; Heinzerling et al, 1974a,b; Larsen and Tollersrud, 1981; Marsh et al, 1981; 1982). Selenium at levels above the .1 ppm generally accepted as nutritionally adequate enhanced the primary immune response in mice
1 Supported by State and Hatch funds allocated to the Georgia Agricultural Experiment Stations of the University of Georgia. 2 On leave from the Faculty of Veterinary-University Federal Fluminense, Brazil and partially supported by a scholarship from the Coordenadoria de Aperfeicoamento de Pessoal de Nivel Superior (CAPES). 3 To whom correspondence should be addressed.
to sheep erythrocytes (Spallholz et al, 1973). Nutritional deficiencies of vitamin E, or Se, or both impaired immune function, as measured by the humoral response to sheep erythrocytes in young chicks (Marsh et al, 1981). Deficiencies of vitamin E and Se in chicks depressed bursa weight, reduced the overall number of lymphocytes found in the primary lymphoid organs and spleen, and resulted in destructive histological changes within these tissues (Marsh et al, 1982). Tengerdy et al. (1972) reported that chicks and hens fed a diet supplemented with 130 mg vitamin E/kg of feed had a significantly increased immune response as measured by the antibody plaque forming cell test or by hemagglutination that chickens fed a diet without the vitamin E supplement. Dietary supplementation with 250 and 300 mg of vitamin E/kg of diet increased protection in chicks against a moderate E. colt infection (Heinzerling et al, 1974a). The majority, of studies report enhanced immune response due to dietary Se and vitamin E supplementation using sheep erythrocytes as antigen. Therefore, studies were conducted to determine if dietary supplementation of a cornsoybean meal diet with Se or vitamin E would enhance the immune response of chickens to coccidiosis using performance, judged by body
1136
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ABSTRACT Six experiments were conducted using broiler chickens to study the effect of selenium (Se) or vitamin E supplementation of a corn-soybean meal diet on the immune response to coccidiosis. Immunized chickens fed diets supplemented with .25 ppm Se or 100 IU vitamin F./kg of diet had increased body weight gain and feed intake and a tendency for lower feed conversion ratio than chickens fed unsupplemented diet after a challenge with 150,000 oocysts of Eimeria tenella. In two experiments, chickens fed .25 and .50 ppm of Se and immunized against E. tenella had higher body weight gain and a tendency for higher feed intake and lower feed conversion ratio than unsupplemented chickens when challenged with 150,000 oocysts of E. tenella. Except for a reduction on cecal lesion scores and blood packed cell volume in Experiments 1 and 4, respectively, no dietary effect was observed on cecal lesion score or blood packed cell volume of immunized chickens. Dietary supplementation with selenium or vitamin E reduced mortality and increased body weight gain of nonimmunized chickens infected with E. tenella in three of four experiments. These studies suggest that immunization of chickens against coccidiosis is enhanced by Se or vitamin E supplementation. (Key words: chicken, coccidia, coccidiosis, Eimeria, Eimeria tenella, Eimeria maxima, immunity, selenium, vitamin E)
IMMUNITY TO COCCIDIOSIS
weight gain and feed conversion as measurements.
1137
TABLE 2. Analysis of the selenium (Se) content of the diets (ppm) Experiment n u m b :r
MATERIALS AND METHODS
TABLE 1. Composition of the basal diet Ingredients Yellow corn Soybean meal (48.5% p rotein) Poultry fat Dicalcium p h o s p h a t e Limestone Salt DL-Methionine Vitamin m i x 1 Trace mineral m i x 2 Calculated composition Crude protein, % Metabolizable energy, kcal/kg Calcium, % Phosphorus, available, %
(%) 53.50 37.50 5.00 1.63 1.37 .50 .20 .25 .05 22.9 3200 .95 .44
'Provides per kilogram of diet; vitamin A, 11,000 IU; vitamin D 3 , 1,100 ICU; riboflavin, 4.4 mg; Ca pantothenate, 12.0 mg; nicotinic acid, 44.0 mg: choline chloride, 220.0 mg; vitamin B 1 2 , 6.6 Mg: vitamin B 6 , 2.2 mg; menadione, .1 mg (as MSBC) folic acid, .55 mg; D-biotin, .11 mg; thiamine, 2.2 mg (as thiamine mononitrate). 'Provides as parts per million of diet; manganese, 60; zinc, 50; iron, 30; copper, 5; iodine, 1.05.
1
2
3
4
5 and 6
Basal + .1 p p m Se + .25 p p m Se + .50 p p m Se + 1.0 p p m Se
.09
.11
.08
.31
.37
.33
.09 .17 .31
.09 .18 .32 .57
.97
Chickens that died between 4 and 8 days postinoculation were reported as mortality due to coccidial infection (dead chickens were not examined for specific lesions of coccidiosis). Body weight gain, feed intake, and feed conversion ratio were determined for the period from the inoculation to 6 days postinoculation. For the determination of body weight gain, only chickens alive at 6 days postinoculation were used. From 6 chickens per treatment, blood samples were taken by heart puncture, using a heparinized syringe, for blood packed cell volume (PCV) determination by the microhematocrit method (Johnson, 1955) at 6 days postinoculation. These chickens were killed by cervical dislocation and intestinal lesion scores were graded zero to four on an arbitrary scale in the manner described by Johnson and Reid (1970). The data generated by these studies were analyzed using the general linear models procedure of the Statistical Analysis System (SAS, 1979) in conjunction with the Duncan separation of means options to locate significant (P«.05) differences between more than two means. Student's t test of SAS was used to locate differences between two means. Arc sine transformation was used on all of the percentage data analyzed. RESULTS
The body weight of chickens at the day of challenge is shown in Table 3. No effect was observed of Se or vitamin E supplementation of the basal diet on body weight at the day of challenge with coccidia. Also no effect of the immunization programs on body weight at the day of challenge was observed. Experiment 1. Immunized chickens performed better, independent of dietary treatment, than nonimmunized chickens when
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Day-old male broiler chicks of the Hubbard strain were housed in electrically heated battery brooders with feed and water supplied ad libitum. Four groups of 8 chicks per group were randomly allocated per treatment in all experiments except in Experiment 1 (a preliminary experiment) when a group of 10 chicks per treatment was used. Composition of the basal diet, which contained no supplementary Se, vitamin E,. or antioxidants is shown in Table 1. Sodium selenite served as the source of supplemental Se and DL-alphatocopheryl acetate of vitamin E. Diets were analyzed for their Se content (Table 2) by the fluorometric method of Whetter and Ullrey (1978). Coccidial immunization and challenge of chickens were produced by oral inoculation with a water suspension of sporulated oocysts. Chickens were challenged with 150,000 oocysts of E. tenella at 32, 25, 22, 25, and 25 days of age in Experiments 1, 2, 3, 4, and 5, respectively, and with 50,000 oocysts of E. maxima at 22 days of age in Experiment 6.
Diets
1138
COLNAGO ET AL. TABLE 3. Body weight at the day of challenge1 Treatments
Diets
__ +
Experiment number2 1
2
3
4
1006 991
697 666
581 611
998 1022
702 683
613 604
710 726 720 704 729 718
+
+ +
-
5
6
717 727 710
578 609 592
697 686
591 595
723 713
+
-
1017 958
+
767 675
607 604
'Chickens were challenged at 32, 25, 22, 25, 25, and 22 days of age in Experiments 1, 2, 3, 4, 5, and i respectively. 2
No significant differences (P<.05) observed.
exposed to a challenge infection (Table 4). Nonimmunized chickens fed Se or vitamin E-supplemented diets and infected with E. tenella had lower mortality than chickens fed the basal diet. Nonimmunized, challenged chickens fed the vitamin E-supplemented diet had higher body weight gain, and those fed the
Se-supplemented diet had higher blood PCV than chickens fed the basal diet. No dietary effect was observed on cecal lesions of nonimmunized infected chickens. Immunized chickens fed dietary Se or vitamin E had higher body weight gain and lower cecal lesion scores than chickens fed the basal diet when exposed
TABLE 4. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 1) Inocu]lations 1
Diets
Immunization
Challenge
+
+ +
30.0 0
Body weight2 gain, g/chick
99b, B
+
+ +
Blood packed cell volume, %
+
+ +
24.6a,A
19.4b,A 25.7a,A
26.4a-A
Cecal lesion scores
+
+ +
3.2 a ,A 1.3b,A
3.2 a ,A .3b,B
3.2 a ,A .3b,B
Parameters Mortality, %
Basal
a c
255 ,
14.5b,B
+ .25 p p m Se 0 0
+ 100 IU of vitamin E/kg 0 0
193b,AB
198b, A
29oa,B
328a>A
18.4b,AB
' ' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1
Immunization was produced by one dose of 50,000 oocysts of E. tenella per chick at 14 days of age.
2
Body weight gain from the inoculation until 6 days postinoculation (32 to 38 days of age).
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Basal Basal + .1 p p m selenium (Se) + .1 p p m Se + .25 p p m Se + .25 p p m Se + .50 p p m Se + 1.0 p p m Se + 1.0 p p m Se + 100 IU, vitamin E/kg + 100 IU vitamin E/kg
Immunization
IMMUNITY TO COCCIDIOSIS
independent of the dietary treatment (Table 6). No significant difference was observed in mortality, blood PCV, and cecal lesion scores due to either diets or immunization. A tendency for lower mortality due to E. tenella infection in chickens fed diets supplemented with Se or vitamin E was observed in both immunized and nonimmunized chickens. Selenium and vitamin E supplementation increased body weight gain of both immunized and nonimmunized chickens infected with E. tenella. Feed intake of chickens fed diets with either Se or vitamin E was higher than that of chickens fed the basal diet. No dietary effect was observed on feed conversion ratio in either immunized or nonimmunized chickens, but immunized chickens had significantly better feed conversion ratios. Experiment 4. In general, immunized chickens performed better than nonimmunized chickens when challenged with E. tenella (Table 7). Nonimmunized, challenged chickens fed .1 or .25 ppm of Se had higher mortality than chickens fed the basal or 1.0 ppm of Se diets. No dietary effect on body weight gain, feed intake, feed conversion ratio, and blood PCV
TABLE 5. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 2) Inocu!lations 1
Diets
Immunization
Challenge
+
+ +
Body weight gain,2 g/chick
+ +
199b,B
247b,A
+
265a3
293a,A
Feed intake, 2 g/chick
+ +
488a.A 511a.A
507b,A
+
Feed conversion2
+
+ +
Blood packed cell volume, %
+
+ +
18.5M 26.1a.A
2i.6b,AB a
Cecal lesion scores
+
+ +
3.6 a > A l.lb.A
2.4a,AB 2.0a.A
Parameters Mortality, %
Basal 27.5a.A' 0^
2.40b'B 1.93 a .A
+ .25 p p m Se
+ 100 IU of vitamin E/kg
3.0a3 0a
564a.B
lO.9a.AB 0a 248b,A 2743.B 512a.A 527a.AB
2.06a.A 1.93a.A
25.1 .A
2.27b>B i:92a.A 25.5a.A 25.0a.A 15
a,B
I
9a,A
' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age. 2
Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
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to a challenge infection. No dietary effect on blood PCV of immunized chickens was observed due to E, tenella infection. Experiment 2. Immunized chickens performed better, independently of the dietary treatment, than nonimmunized chickens when exposed to a challenge infection (Table 5). Nonimmunized, challenged chickens fed the Se-supplemented diet had significantly lower mortality and feed conversion than chickens fed the basal diet. Vitamin E supplementation of nonimmunized infected chickens resulted in significantly higher blood PCV and lower cecal lesion scores than that observed in chickens fed the basal diet. Nonimmunized, infected chickens fed the Se- or vitamin E-supplemented diets had significantly higher body weight gain than chickens fed the basal diet. Immunized chickens fed Se had significantly higher body weight gain and feed intake than chickens fed the basal diet. No dietary effect was observed in feed conversion, blood PCV, and cecal lesion scores of immunized chickens. Experiment 3. In general, immunized chickens performed better than nonimmunized chickens when exposed to a challenge infection
1139
COLNAGO ET AL.
1140
TABLE 6. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 3) Inocu lations1
Diets
Immunization
Challenge
+
+ +
43.8 22.8
Body weight gain,3 g/chick
+ +
+
114D.B 212a,B
174b,A 236a-AB
149b, AB 250 a > A
Feed intake, 3 g/chick
+
+ +
402 b .A 431a3
438 a .A 446 a ,AB
472a,A
Feed conversion3
+
+
Blood packed cell volume, %
+
+ +
17.2 17.8
18.7 18.0
17.0 17.7
Cecal lesion scores2
+ +
3.5 3.3
3.3 3.0
3.7 3.2
Parameters Mortality, 2 %
+
7.09a-A 3.48 b .A
.25 ppm Se
+ 100 IU of vitamin E/kg 29.8 12.3
35.1 10.4
394b,A
5.13 a . A 2.99b,A
6.38 a .A 3.04b, A
' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1
Immunization was produced by one dose of 1,000 oocysts of E. tenella per chick at 12 days of age.
2
No significant differences (P<.05) observed.
3
Measurements taken from the inoculation until 6 days postinoculation (22 to 28 days of age).
was observed in nonimmunized, challenged chickens; however, the cecal lesion scores of chickens fed the diet with 1.0 ppm of Se were higher tJian those of chickens fed the basal, . 1 , or .25 ppm Se diets. Among immunized chickens a tendency for better body weight gain, feed intake, and feed conversion ratio was observed for chickens fed the Se-supplemented diets. The blood PCV of chickens fed the .25 or 1.0 ppm of Se were lower than the chickens fed basal or .1 ppm Se diets. The cecal lesions score of chickens fed .1 ppm Se were lower than those of chickens fed the basal or .25 ppm Se diets. Experiment 5. No mortality due to E. tenella infection was observed among immunized chickens (Table 8). Nonimmunized, challenged chickens had 12.9% of mortality (data not shown in Table 8). No significant difference due to -E. tenella infection was observed in body weight gain of immunized chickens fed the basal diet or the different levels of Se; however, immunized chickens fed the basal or .1 ppm Se diets had significantly lower body weight gain than chickens not infected (positive
control), while chickens fed the .25 or .50 ppm Se diets had similar body weight gain to noninfected chickens. Nonimmunized, challenged chickens had the lowest body weight gain, which was significantly lower than the noninfected (positive control) and immunized, challenged chickens. No difference in feed intake, feed conversion ratio, and blood PCV was observed between noninfected chickens and challenged chickens fed different levels of Se. Nonimmunized, challenged chickens had significantly lower feed intake and blood PCV and a higher feed conversion ratio than the other groups. Among immunized chickens, no Se effect was observed in cecal lesion scores. Experiment 6. No significant difference due to E. maxima infection was observed in body weight gain and feed conversion ratio of immunized chickens fed diets with different levels of Se (Table 9). Immunized chickens exposed to a challenge infection had similar body weight gain and feed conversion ratio to the noninfected chickens. No difference in feed intake was observed between immunized chickens receiving different levels of Se, but immunized,
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+
Basal
IMMUNITY TO COCCIDIOSIS
1141
TABLE 7. Effects of different levels of selenium (Se) on development of immunity to Eimeria tenella (Experiment 4) Inocul ations 2 zation
Challenge
A d d e d Se ( p p m ) 0
.10
.25 _ ,.
+
a
6.3 ,B 3.ia,A
a
20.3 ,A 0b,A
1.00
„^ 19.8a.A 3.1b,A
6.3a,B 0a,A
+
+
+ +
147a,A 20ia,A
121b>A 222a.A
130 b >A 228a.A
155b>A 223a,A
+
+ +
3 86a, A 423a>A
416a.A 435a,A
378b.A 437a,A
407a,A 436a,A
+
+
+
2.71a,A 2.24a.A
3.62b.A 2.16a.A
+
+
23.5a'A 22.5a,AB
21.2a,A 26.ia,A
20.6a.A 19.9a-B
+
+ +
2.8 a > B 3.0 a .A
2.8 a ,B 2.0a3
2.8a,B 3.2 a .A
+
2.90a.A l.94a,A
3.33b.A 2.06a'A
20.6a-A 19.5a,B
3.8b.A 2.7a,AB
abAB ' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age. 7
Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
challenged chickens fed the basal diet had significantly lower feed intake than chickens not infected. Intestinal lesion scores of nonimmunized, challenged chickens were higher than those of immunized, challenged chickens.
DISCUSSION It has been suggested that there are at least three stages of immunity to E. tenella; chickens may be immunized so that they are totally resistant to the parasite and no development occurs; chickens may become resistant to the degree where oocysts are discharged after a challenge but no lesions occur; or chickens may be resistant to the clinical effects of the disease despite having severe lesions (Long et al., 1980). Therefore, in our studies the term
immunization or immunized chickens refers to chickens that have been exposed to at least one oral inoculation with sporulated oocysts of the species of Eimeria studied. This treatment was aimed at producing partial immunity to coccidial infection in chickens given the unsupplemented diet. In most of our studies E. tenella was used to ascertain the effects of Se or vitamin E on the immune response of chickens to coccidiosis. Species of Eimeria differ in their immunogenicity (Rose, 1973). Rose and Long (1962) investigated the immunizing abilities of four different species of Eimeria in fowl and placed the test species in the following order of descending immunogenicity: E. maxima, E. acervulina, E. tenella, and E. necatrix. In Experiment 6, where the effects were studied
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+
1142
COLNAGO ET AL. TABLE 8. Effects of different levels of selenium (Se) on development of immunity to Eimeria tenella (Experiment 5) Inocuilations2
(added Se in ppm)
Immunization
Challenge
Body weight gain1
Feed conversion1
Feed intake 1
0 .1 .25 .5
_ —
—
+ + +
+
27.8 a 20.2 e 25.8 a b 26.0 a b 25.4 a b 27.6 a
0
3.8 a 1.2b 1.4b 2.0 b 1.4b
a
' ' c Means within a column with different letter superscripts are significantly different (P<.05). •Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
2 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age.
mechanisms of defense to a primary infection, and therefore improving the overall defense of chickens against coccidial infection. The mechanisms by which Se and vitamin E protect the animal against infection are not known. However, it has been shown that Se and vitamin E increase phagocytic activity in several species (Boyne and Arthur, 1979; Heinzerling et al, 1974b; Tengerdy and Brown, 1977; Likoff et al, 1981). Colnago et al. (1984) reported that Se supplementation of the diet given to chickens infected with coccidia resulted in changes to the peripheral leucocyte numbers at 6 and 11 days postinoculation. It was suggested that Se protects the leucocytes from self destruction during the phagocytic
of various levels of Se on the immunization of chickens against E, maxima, a highly immunogenic specie, no dietary effect was observed among immunized birds due to Se supplementation. This suggests that the effect of Se supplementation depends upon the species of Eimeria used. Dietary Se or vitamin E also reduced mortality and increased body weight gain (Experiments 1, 2, and 3) in nonimmunized chickens infected with E. tenella. These results are in accord witli those reported earlier (Jensen et al., 1978). The results of the present investigation suggest that Se or vitamin E not only enhances the immune response of immunized chickens but also appears to affect the
TABLE 9. Effects of different levels of selenium (Se) on development of immunity to Eimeria maxima (Experiment 6) Inocuilations2 (added Se in ppm)
Immunizations
Challenge
.1 .1
_ _
—
.1 .25 .5
+ + + +
Body weight gain1
Feed intake 1
Feed conversion1
Lesion scores
, ,,., ,
0
a
'
1 2
+ + + + +
a
261 168 b 223 a 253 a 237 a 245 a
465 a 407b 400° 454ab 411ab 431ab
1.79b 2.43 a 1.81 b 1.80b
0C
1.73D
0C
1.76b
1.4b
,c
Means within a column with different letter superscripts are significantly different (P<.05). Measurements taken from the inoculation until 6 days postinoculation (22 to 28 days of age). Immunization was produced by one dose of 50 oocysts of E. maxima per chick at 12 days of age.
3.6 a 1.2 bc 1.2bc
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491 368 b 475 a 466 a 467 a 487 a
234 b 222 b 257ab 247ab
+ + +
1.76a 5.49 b 2.03 a 2.09 a 1.82 a 1.96a
a
74c
+
+
279
a
Cecal lesion scores
(%)
(g/chi ck) .1 .1
Blood packed cell volume
IMMUNITY TO COCCIDIOSIS
Although the Se content of the basal diets used in our studies (Table 2) was very close to .1 ppm, which is generally accepted as nutritionally adequate for chickens, enhancement in the immune response of chickens to coccidiosis was observed due to dietary supplementation with Se. These results are in accord with previous studies (Tengerdy et al., 1972, 1973; Spallholz et al, 1973; Likoff et al, 1981) that suggested that the Se and vitamin E requirement for the full expression of the immune response is higher than the currently recommended levels. Our results also indicate that the reported enhancement of the immune response due to Se, vitamin E, or both evaluated by indirect methods (hemagglutination titers, plaque forming cells tests, etc.) may be of practical importance in improving immunization programs in the poultry industry. ACKNOWLEDGMENTS We are grateful to Joyce Johnson for technical assistance. REFERENCES Boyne, R., and J. R. Arthur, 1979. Alterations of neutrophil function in selenium deficient cattle. J. Comp. Pathol. 89:151-158. Colnago, G. L., L. S. Jensen, and P. L. Long, 1984. Effect of selenium on peripheral blood leucocytes of chickens infected with F.imeria. Poultry Sci. 6 3 : 8 9 6 - 9 0 3 . Heinzerling, R. H., C. F. Nockels, C. L. Quarles, and R. P. Tengerdy, 1974a. Protection of chicks against E. coli infection by dietary supplementation with vitamin E. Proc. Soc. Exp. Biol. Med. 146:279-283. Heinzerling, R. H., R. P. Tengerdy, L. L. Wick, and D. C. Lucker, 1974b. Vitamin E protects mice against Diplococcus pneumoniae type I infection. Infect Immun. 10:1292-1295.
Jensen, L. S., J. Johnson, and M. D. Ruff, 1978. Selenium status and response of broiler chicks to coccidial infection. Poultry Sci. 57:1147. (Abstr.) Johnson, P. M., 1955. Hematocrit values for the chick embryo at various age. Am. J. Physiol. 180: 361-362. Johnson, J., and W. M. Reid, 1970. Anticoccidial drugs: Lesion scoring techniques in battery and floor pen experiments with chickens. Exp. Parasitol. 28:30-36. Langweiler, M., R. D. Schultz, and B. E. Sheffy, 1981. Effect of vitamin E deficiency on the proliferative response of canine lymphocytes. Am. J. Vet. Res. 42:1681-1685. Larsen, H. J., and S. Tollersrud, 1981. Effect of dietary vitamin E and selenium on the phytohaemagglutinin response of pig lymphocytes. Res. Vet. Sci. 31:301-305. Likoff, R. O., D. R. Guptill, L. M. Lawrence, C. C. McKay, M. M. Mathias, C. F. Nockels, and R. P. Tengerdy, 1981. Vitamin E and aspirin depress prostaglandins in protection of chickens against E. coli infection. Am. J. Clin. Nutr. 35:245-251. Long, P. L., J. Johnson, and R. D. Wyatt, 1980. Eimeria tenella: Clinical effects in partially immune and susceptible chickens. Poultry Sci. 59:2221-2224. Marsh, J. A., R. R. Dietert, and G. F. Combs, Jr., 1981. Influence of dietary selenium and vitamin E on the humoral immune response of the chick. Proc. Soc. Exp. Biol. Med. 66:228-236. Marsh, J. A., R. R. Dietert, and G. F. Combs, Jr., 1982. Effects of dietary deficiencies of vitamin E and selenium on the primary lymphoid organs of the chick. Fed. Proc. 41:341. (Abstr.) Rose, M. E., and P. L. Long, 1962. Immunity to four species of Eimeria in fowl. Immunology 5: 79-92. Rose, M. E., 1973. Immunity. Pages 2 9 5 - 3 4 1 in The Coccidia: Eimeria, Isospora, Toxoplasma and Related Genera. D. M. Hammong and P. L. Long, ed. University Park, Baltimore, MD. Spallholz, J. E., J. L. Martin, M. L. Gerlach, and R. H. Heinzerling, 1973. Immunologic responses of mice fed diets supplemented with selenite selenium. Proc. Soc. Exp. Biol. Med. 143:685 — 689. Statistical Analysis System Institute, 1979. SAS User's Guide, ed. SAS Inst., Inc., Raleigh, NC. Tengerdy, R. P., Heinzerling, and C. F. Nockels, 1972. Effect of vitamin E on the immune response of hypoxic and normal chicks. Infect. Immun. 5:987-989. Tengerdy, R. P., R. H. Heinzerling, G. L. Brown, and M. M. Mathias, 1973. Enhancement of the humoral immune response by vitamin E. Int. Arch. Allergy 44:221-232. Tengerdy, R. P., and C. F. Nockels, 1975. Vitamin E or vitamin A protects chicks against E. coli infection. Poultry Sci. 54:1292-1296. Tengerdy, R. P., and J. C. Brown, 1977. Effect of vitamin E and A on humoral immunity and phagocytosis in £. coli infected chicken. Poultry Sci. 56:957-963. Whetter, P. A., and D. E. Ullrey, 1978. Improved fluorometric method for determining selenium. J. Assoc. Offic. Anal. Chem. 61:927-930.
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activity. Therefore, the leucocytes are retained at the site of infection, protecting the host against the pathogenic effects of the parasite. Selenium and vitamin E have also been shown to enhance the proliferative response of lymphocytes to mitogens (Langweiler et al, 1981; Larsen and Tollersrud, 1981) and antibody titers (Spallholz et al, 1973; Tengerdy and Nockels, 1975). Likoff et al. (1981) showed that supplementary vitamin E depressed prostaglandin levels in the immunopoietic organs of chickens. They suggested that the vitamin E enhancement of the immune response and the overall protection from infection is mediated through a reduction in synthesis of prostaglandins in infected chickens.
1143
1984 Poultry Science 63:1136-1143 INTRODUCTION
The vertebrates have basically two lines of defense against infectant microorganisms. These consist of specific or immune response (humoral and cellular) and a nonspecific system, which provides broad, generalized types of protection not directed specifically against microorganisms. The nutritional status of an animal has a significant effect on host defense mechanisms. Selenium (Se) and vitamin E have been shown to play a major role in the development and maintenance of the defense systems (Tengerdy et al, 1973; Spallholz et al, 1973; Heinzerling et al, 1974a,b; Larsen and Tollersrud, 1981; Marsh et al, 1981; 1982). Selenium at levels above the .1 ppm generally accepted as nutritionally adequate enhanced the primary immune response in mice
1 Supported by State and Hatch funds allocated to the Georgia Agricultural Experiment Stations of the University of Georgia. 2 On leave from the Faculty of Veterinary-University Federal Fluminense, Brazil and partially supported by a scholarship from the Coordenadoria de Aperfeicoamento de Pessoal de Nivel Superior (CAPES). 3 To whom correspondence should be addressed.
to sheep erythrocytes (Spallholz et al, 1973). Nutritional deficiencies of vitamin E, or Se, or both impaired immune function, as measured by the humoral response to sheep erythrocytes in young chicks (Marsh et al, 1981). Deficiencies of vitamin E and Se in chicks depressed bursa weight, reduced the overall number of lymphocytes found in the primary lymphoid organs and spleen, and resulted in destructive histological changes within these tissues (Marsh et al, 1982). Tengerdy et al. (1972) reported that chicks and hens fed a diet supplemented with 130 mg vitamin E/kg of feed had a significantly increased immune response as measured by the antibody plaque forming cell test or by hemagglutination that chickens fed a diet without the vitamin E supplement. Dietary supplementation with 250 and 300 mg of vitamin E/kg of diet increased protection in chicks against a moderate E. colt infection (Heinzerling et al, 1974a). The majority, of studies report enhanced immune response due to dietary Se and vitamin E supplementation using sheep erythrocytes as antigen. Therefore, studies were conducted to determine if dietary supplementation of a cornsoybean meal diet with Se or vitamin E would enhance the immune response of chickens to coccidiosis using performance, judged by body
1136
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ABSTRACT Six experiments were conducted using broiler chickens to study the effect of selenium (Se) or vitamin E supplementation of a corn-soybean meal diet on the immune response to coccidiosis. Immunized chickens fed diets supplemented with .25 ppm Se or 100 IU vitamin F./kg of diet had increased body weight gain and feed intake and a tendency for lower feed conversion ratio than chickens fed unsupplemented diet after a challenge with 150,000 oocysts of Eimeria tenella. In two experiments, chickens fed .25 and .50 ppm of Se and immunized against E. tenella had higher body weight gain and a tendency for higher feed intake and lower feed conversion ratio than unsupplemented chickens when challenged with 150,000 oocysts of E. tenella. Except for a reduction on cecal lesion scores and blood packed cell volume in Experiments 1 and 4, respectively, no dietary effect was observed on cecal lesion score or blood packed cell volume of immunized chickens. Dietary supplementation with selenium or vitamin E reduced mortality and increased body weight gain of nonimmunized chickens infected with E. tenella in three of four experiments. These studies suggest that immunization of chickens against coccidiosis is enhanced by Se or vitamin E supplementation. (Key words: chicken, coccidia, coccidiosis, Eimeria, Eimeria tenella, Eimeria maxima, immunity, selenium, vitamin E)
IMMUNITY TO COCCIDIOSIS
weight gain and feed conversion as measurements.
1137
TABLE 2. Analysis of the selenium (Se) content of the diets (ppm) Experiment n u m b :r
MATERIALS AND METHODS
TABLE 1. Composition of the basal diet Ingredients Yellow corn Soybean meal (48.5% p rotein) Poultry fat Dicalcium p h o s p h a t e Limestone Salt DL-Methionine Vitamin m i x 1 Trace mineral m i x 2 Calculated composition Crude protein, % Metabolizable energy, kcal/kg Calcium, % Phosphorus, available, %
(%) 53.50 37.50 5.00 1.63 1.37 .50 .20 .25 .05 22.9 3200 .95 .44
'Provides per kilogram of diet; vitamin A, 11,000 IU; vitamin D 3 , 1,100 ICU; riboflavin, 4.4 mg; Ca pantothenate, 12.0 mg; nicotinic acid, 44.0 mg: choline chloride, 220.0 mg; vitamin B 1 2 , 6.6 Mg: vitamin B 6 , 2.2 mg; menadione, .1 mg (as MSBC) folic acid, .55 mg; D-biotin, .11 mg; thiamine, 2.2 mg (as thiamine mononitrate). 'Provides as parts per million of diet; manganese, 60; zinc, 50; iron, 30; copper, 5; iodine, 1.05.
1
2
3
4
5 and 6
Basal + .1 p p m Se + .25 p p m Se + .50 p p m Se + 1.0 p p m Se
.09
.11
.08
.31
.37
.33
.09 .17 .31
.09 .18 .32 .57
.97
Chickens that died between 4 and 8 days postinoculation were reported as mortality due to coccidial infection (dead chickens were not examined for specific lesions of coccidiosis). Body weight gain, feed intake, and feed conversion ratio were determined for the period from the inoculation to 6 days postinoculation. For the determination of body weight gain, only chickens alive at 6 days postinoculation were used. From 6 chickens per treatment, blood samples were taken by heart puncture, using a heparinized syringe, for blood packed cell volume (PCV) determination by the microhematocrit method (Johnson, 1955) at 6 days postinoculation. These chickens were killed by cervical dislocation and intestinal lesion scores were graded zero to four on an arbitrary scale in the manner described by Johnson and Reid (1970). The data generated by these studies were analyzed using the general linear models procedure of the Statistical Analysis System (SAS, 1979) in conjunction with the Duncan separation of means options to locate significant (P«.05) differences between more than two means. Student's t test of SAS was used to locate differences between two means. Arc sine transformation was used on all of the percentage data analyzed. RESULTS
The body weight of chickens at the day of challenge is shown in Table 3. No effect was observed of Se or vitamin E supplementation of the basal diet on body weight at the day of challenge with coccidia. Also no effect of the immunization programs on body weight at the day of challenge was observed. Experiment 1. Immunized chickens performed better, independent of dietary treatment, than nonimmunized chickens when
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Day-old male broiler chicks of the Hubbard strain were housed in electrically heated battery brooders with feed and water supplied ad libitum. Four groups of 8 chicks per group were randomly allocated per treatment in all experiments except in Experiment 1 (a preliminary experiment) when a group of 10 chicks per treatment was used. Composition of the basal diet, which contained no supplementary Se, vitamin E,. or antioxidants is shown in Table 1. Sodium selenite served as the source of supplemental Se and DL-alphatocopheryl acetate of vitamin E. Diets were analyzed for their Se content (Table 2) by the fluorometric method of Whetter and Ullrey (1978). Coccidial immunization and challenge of chickens were produced by oral inoculation with a water suspension of sporulated oocysts. Chickens were challenged with 150,000 oocysts of E. tenella at 32, 25, 22, 25, and 25 days of age in Experiments 1, 2, 3, 4, and 5, respectively, and with 50,000 oocysts of E. maxima at 22 days of age in Experiment 6.
Diets
1138
COLNAGO ET AL. TABLE 3. Body weight at the day of challenge1 Treatments
Diets
__ +
Experiment number2 1
2
3
4
1006 991
697 666
581 611
998 1022
702 683
613 604
710 726 720 704 729 718
+
+ +
-
5
6
717 727 710
578 609 592
697 686
591 595
723 713
+
-
1017 958
+
767 675
607 604
'Chickens were challenged at 32, 25, 22, 25, 25, and 22 days of age in Experiments 1, 2, 3, 4, 5, and i respectively. 2
No significant differences (P<.05) observed.
exposed to a challenge infection (Table 4). Nonimmunized chickens fed Se or vitamin E-supplemented diets and infected with E. tenella had lower mortality than chickens fed the basal diet. Nonimmunized, challenged chickens fed the vitamin E-supplemented diet had higher body weight gain, and those fed the
Se-supplemented diet had higher blood PCV than chickens fed the basal diet. No dietary effect was observed on cecal lesions of nonimmunized infected chickens. Immunized chickens fed dietary Se or vitamin E had higher body weight gain and lower cecal lesion scores than chickens fed the basal diet when exposed
TABLE 4. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 1) Inocu]lations 1
Diets
Immunization
Challenge
+
+ +
30.0 0
Body weight2 gain, g/chick
99b, B
+
+ +
Blood packed cell volume, %
+
+ +
24.6a,A
19.4b,A 25.7a,A
26.4a-A
Cecal lesion scores
+
+ +
3.2 a ,A 1.3b,A
3.2 a ,A .3b,B
3.2 a ,A .3b,B
Parameters Mortality, %
Basal
a c
255 ,
14.5b,B
+ .25 p p m Se 0 0
+ 100 IU of vitamin E/kg 0 0
193b,AB
198b, A
29oa,B
328a>A
18.4b,AB
' ' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1
Immunization was produced by one dose of 50,000 oocysts of E. tenella per chick at 14 days of age.
2
Body weight gain from the inoculation until 6 days postinoculation (32 to 38 days of age).
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Basal Basal + .1 p p m selenium (Se) + .1 p p m Se + .25 p p m Se + .25 p p m Se + .50 p p m Se + 1.0 p p m Se + 1.0 p p m Se + 100 IU, vitamin E/kg + 100 IU vitamin E/kg
Immunization
IMMUNITY TO COCCIDIOSIS
independent of the dietary treatment (Table 6). No significant difference was observed in mortality, blood PCV, and cecal lesion scores due to either diets or immunization. A tendency for lower mortality due to E. tenella infection in chickens fed diets supplemented with Se or vitamin E was observed in both immunized and nonimmunized chickens. Selenium and vitamin E supplementation increased body weight gain of both immunized and nonimmunized chickens infected with E. tenella. Feed intake of chickens fed diets with either Se or vitamin E was higher than that of chickens fed the basal diet. No dietary effect was observed on feed conversion ratio in either immunized or nonimmunized chickens, but immunized chickens had significantly better feed conversion ratios. Experiment 4. In general, immunized chickens performed better than nonimmunized chickens when challenged with E. tenella (Table 7). Nonimmunized, challenged chickens fed .1 or .25 ppm of Se had higher mortality than chickens fed the basal or 1.0 ppm of Se diets. No dietary effect on body weight gain, feed intake, feed conversion ratio, and blood PCV
TABLE 5. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 2) Inocu!lations 1
Diets
Immunization
Challenge
+
+ +
Body weight gain,2 g/chick
+ +
199b,B
247b,A
+
265a3
293a,A
Feed intake, 2 g/chick
+ +
488a.A 511a.A
507b,A
+
Feed conversion2
+
+ +
Blood packed cell volume, %
+
+ +
18.5M 26.1a.A
2i.6b,AB a
Cecal lesion scores
+
+ +
3.6 a > A l.lb.A
2.4a,AB 2.0a.A
Parameters Mortality, %
Basal 27.5a.A' 0^
2.40b'B 1.93 a .A
+ .25 p p m Se
+ 100 IU of vitamin E/kg
3.0a3 0a
564a.B
lO.9a.AB 0a 248b,A 2743.B 512a.A 527a.AB
2.06a.A 1.93a.A
25.1 .A
2.27b>B i:92a.A 25.5a.A 25.0a.A 15
a,B
I
9a,A
' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age. 2
Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
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to a challenge infection. No dietary effect on blood PCV of immunized chickens was observed due to E, tenella infection. Experiment 2. Immunized chickens performed better, independently of the dietary treatment, than nonimmunized chickens when exposed to a challenge infection (Table 5). Nonimmunized, challenged chickens fed the Se-supplemented diet had significantly lower mortality and feed conversion than chickens fed the basal diet. Vitamin E supplementation of nonimmunized infected chickens resulted in significantly higher blood PCV and lower cecal lesion scores than that observed in chickens fed the basal diet. Nonimmunized, infected chickens fed the Se- or vitamin E-supplemented diets had significantly higher body weight gain than chickens fed the basal diet. Immunized chickens fed Se had significantly higher body weight gain and feed intake than chickens fed the basal diet. No dietary effect was observed in feed conversion, blood PCV, and cecal lesion scores of immunized chickens. Experiment 3. In general, immunized chickens performed better than nonimmunized chickens when exposed to a challenge infection
1139
COLNAGO ET AL.
1140
TABLE 6. Effects of selenium (Se) or vitamin E on development of immunity to Eimeria tenella (Experiment 3) Inocu lations1
Diets
Immunization
Challenge
+
+ +
43.8 22.8
Body weight gain,3 g/chick
+ +
+
114D.B 212a,B
174b,A 236a-AB
149b, AB 250 a > A
Feed intake, 3 g/chick
+
+ +
402 b .A 431a3
438 a .A 446 a ,AB
472a,A
Feed conversion3
+
+
Blood packed cell volume, %
+
+ +
17.2 17.8
18.7 18.0
17.0 17.7
Cecal lesion scores2
+ +
3.5 3.3
3.3 3.0
3.7 3.2
Parameters Mortality, 2 %
+
7.09a-A 3.48 b .A
.25 ppm Se
+ 100 IU of vitamin E/kg 29.8 12.3
35.1 10.4
394b,A
5.13 a . A 2.99b,A
6.38 a .A 3.04b, A
' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1
Immunization was produced by one dose of 1,000 oocysts of E. tenella per chick at 12 days of age.
2
No significant differences (P<.05) observed.
3
Measurements taken from the inoculation until 6 days postinoculation (22 to 28 days of age).
was observed in nonimmunized, challenged chickens; however, the cecal lesion scores of chickens fed the diet with 1.0 ppm of Se were higher tJian those of chickens fed the basal, . 1 , or .25 ppm Se diets. Among immunized chickens a tendency for better body weight gain, feed intake, and feed conversion ratio was observed for chickens fed the Se-supplemented diets. The blood PCV of chickens fed the .25 or 1.0 ppm of Se were lower than the chickens fed basal or .1 ppm Se diets. The cecal lesions score of chickens fed .1 ppm Se were lower than those of chickens fed the basal or .25 ppm Se diets. Experiment 5. No mortality due to E. tenella infection was observed among immunized chickens (Table 8). Nonimmunized, challenged chickens had 12.9% of mortality (data not shown in Table 8). No significant difference due to -E. tenella infection was observed in body weight gain of immunized chickens fed the basal diet or the different levels of Se; however, immunized chickens fed the basal or .1 ppm Se diets had significantly lower body weight gain than chickens not infected (positive
control), while chickens fed the .25 or .50 ppm Se diets had similar body weight gain to noninfected chickens. Nonimmunized, challenged chickens had the lowest body weight gain, which was significantly lower than the noninfected (positive control) and immunized, challenged chickens. No difference in feed intake, feed conversion ratio, and blood PCV was observed between noninfected chickens and challenged chickens fed different levels of Se. Nonimmunized, challenged chickens had significantly lower feed intake and blood PCV and a higher feed conversion ratio than the other groups. Among immunized chickens, no Se effect was observed in cecal lesion scores. Experiment 6. No significant difference due to E. maxima infection was observed in body weight gain and feed conversion ratio of immunized chickens fed diets with different levels of Se (Table 9). Immunized chickens exposed to a challenge infection had similar body weight gain and feed conversion ratio to the noninfected chickens. No difference in feed intake was observed between immunized chickens receiving different levels of Se, but immunized,
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+
Basal
IMMUNITY TO COCCIDIOSIS
1141
TABLE 7. Effects of different levels of selenium (Se) on development of immunity to Eimeria tenella (Experiment 4) Inocul ations 2 zation
Challenge
A d d e d Se ( p p m ) 0
.10
.25 _ ,.
+
a
6.3 ,B 3.ia,A
a
20.3 ,A 0b,A
1.00
„^ 19.8a.A 3.1b,A
6.3a,B 0a,A
+
+
+ +
147a,A 20ia,A
121b>A 222a.A
130 b >A 228a.A
155b>A 223a,A
+
+ +
3 86a, A 423a>A
416a.A 435a,A
378b.A 437a,A
407a,A 436a,A
+
+
+
2.71a,A 2.24a.A
3.62b.A 2.16a.A
+
+
23.5a'A 22.5a,AB
21.2a,A 26.ia,A
20.6a.A 19.9a-B
+
+ +
2.8 a > B 3.0 a .A
2.8 a ,B 2.0a3
2.8a,B 3.2 a .A
+
2.90a.A l.94a,A
3.33b.A 2.06a'A
20.6a-A 19.5a,B
3.8b.A 2.7a,AB
abAB ' ' ' Significant differences (P<.05) between immunization within each diet are represented by different lower case superscripts to the left of the slash. Differences between diets within immunization are represented by different capital superscripts to the right of the slash. 1 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age. 7
Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
challenged chickens fed the basal diet had significantly lower feed intake than chickens not infected. Intestinal lesion scores of nonimmunized, challenged chickens were higher than those of immunized, challenged chickens.
DISCUSSION It has been suggested that there are at least three stages of immunity to E. tenella; chickens may be immunized so that they are totally resistant to the parasite and no development occurs; chickens may become resistant to the degree where oocysts are discharged after a challenge but no lesions occur; or chickens may be resistant to the clinical effects of the disease despite having severe lesions (Long et al., 1980). Therefore, in our studies the term
immunization or immunized chickens refers to chickens that have been exposed to at least one oral inoculation with sporulated oocysts of the species of Eimeria studied. This treatment was aimed at producing partial immunity to coccidial infection in chickens given the unsupplemented diet. In most of our studies E. tenella was used to ascertain the effects of Se or vitamin E on the immune response of chickens to coccidiosis. Species of Eimeria differ in their immunogenicity (Rose, 1973). Rose and Long (1962) investigated the immunizing abilities of four different species of Eimeria in fowl and placed the test species in the following order of descending immunogenicity: E. maxima, E. acervulina, E. tenella, and E. necatrix. In Experiment 6, where the effects were studied
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+
1142
COLNAGO ET AL. TABLE 8. Effects of different levels of selenium (Se) on development of immunity to Eimeria tenella (Experiment 5) Inocuilations2
(added Se in ppm)
Immunization
Challenge
Body weight gain1
Feed conversion1
Feed intake 1
0 .1 .25 .5
_ —
—
+ + +
+
27.8 a 20.2 e 25.8 a b 26.0 a b 25.4 a b 27.6 a
0
3.8 a 1.2b 1.4b 2.0 b 1.4b
a
' ' c Means within a column with different letter superscripts are significantly different (P<.05). •Measurements taken from the inoculation until 6 days postinoculation (25 to 31 days of age).
2 Immunization was produced by three doses of 500 oocysts of E. tenella per chick on 7, 11, and 15 days of age.
mechanisms of defense to a primary infection, and therefore improving the overall defense of chickens against coccidial infection. The mechanisms by which Se and vitamin E protect the animal against infection are not known. However, it has been shown that Se and vitamin E increase phagocytic activity in several species (Boyne and Arthur, 1979; Heinzerling et al, 1974b; Tengerdy and Brown, 1977; Likoff et al, 1981). Colnago et al. (1984) reported that Se supplementation of the diet given to chickens infected with coccidia resulted in changes to the peripheral leucocyte numbers at 6 and 11 days postinoculation. It was suggested that Se protects the leucocytes from self destruction during the phagocytic
of various levels of Se on the immunization of chickens against E, maxima, a highly immunogenic specie, no dietary effect was observed among immunized birds due to Se supplementation. This suggests that the effect of Se supplementation depends upon the species of Eimeria used. Dietary Se or vitamin E also reduced mortality and increased body weight gain (Experiments 1, 2, and 3) in nonimmunized chickens infected with E. tenella. These results are in accord witli those reported earlier (Jensen et al., 1978). The results of the present investigation suggest that Se or vitamin E not only enhances the immune response of immunized chickens but also appears to affect the
TABLE 9. Effects of different levels of selenium (Se) on development of immunity to Eimeria maxima (Experiment 6) Inocuilations2 (added Se in ppm)
Immunizations
Challenge
.1 .1
_ _
—
.1 .25 .5
+ + + +
Body weight gain1
Feed intake 1
Feed conversion1
Lesion scores
, ,,., ,
0
a
'
1 2
+ + + + +
a
261 168 b 223 a 253 a 237 a 245 a
465 a 407b 400° 454ab 411ab 431ab
1.79b 2.43 a 1.81 b 1.80b
0C
1.73D
0C
1.76b
1.4b
,c
Means within a column with different letter superscripts are significantly different (P<.05). Measurements taken from the inoculation until 6 days postinoculation (22 to 28 days of age). Immunization was produced by one dose of 50 oocysts of E. maxima per chick at 12 days of age.
3.6 a 1.2 bc 1.2bc
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491 368 b 475 a 466 a 467 a 487 a
234 b 222 b 257ab 247ab
+ + +
1.76a 5.49 b 2.03 a 2.09 a 1.82 a 1.96a
a
74c
+
+
279
a
Cecal lesion scores
(%)
(g/chi ck) .1 .1
Blood packed cell volume
IMMUNITY TO COCCIDIOSIS
Although the Se content of the basal diets used in our studies (Table 2) was very close to .1 ppm, which is generally accepted as nutritionally adequate for chickens, enhancement in the immune response of chickens to coccidiosis was observed due to dietary supplementation with Se. These results are in accord with previous studies (Tengerdy et al., 1972, 1973; Spallholz et al, 1973; Likoff et al, 1981) that suggested that the Se and vitamin E requirement for the full expression of the immune response is higher than the currently recommended levels. Our results also indicate that the reported enhancement of the immune response due to Se, vitamin E, or both evaluated by indirect methods (hemagglutination titers, plaque forming cells tests, etc.) may be of practical importance in improving immunization programs in the poultry industry. ACKNOWLEDGMENTS We are grateful to Joyce Johnson for technical assistance. REFERENCES Boyne, R., and J. R. Arthur, 1979. Alterations of neutrophil function in selenium deficient cattle. J. Comp. Pathol. 89:151-158. Colnago, G. L., L. S. Jensen, and P. L. Long, 1984. Effect of selenium on peripheral blood leucocytes of chickens infected with F.imeria. Poultry Sci. 6 3 : 8 9 6 - 9 0 3 . Heinzerling, R. H., C. F. Nockels, C. L. Quarles, and R. P. Tengerdy, 1974a. Protection of chicks against E. coli infection by dietary supplementation with vitamin E. Proc. Soc. Exp. Biol. Med. 146:279-283. Heinzerling, R. H., R. P. Tengerdy, L. L. Wick, and D. C. Lucker, 1974b. Vitamin E protects mice against Diplococcus pneumoniae type I infection. Infect Immun. 10:1292-1295.
Jensen, L. S., J. Johnson, and M. D. Ruff, 1978. Selenium status and response of broiler chicks to coccidial infection. Poultry Sci. 57:1147. (Abstr.) Johnson, P. M., 1955. Hematocrit values for the chick embryo at various age. Am. J. Physiol. 180: 361-362. Johnson, J., and W. M. Reid, 1970. Anticoccidial drugs: Lesion scoring techniques in battery and floor pen experiments with chickens. Exp. Parasitol. 28:30-36. Langweiler, M., R. D. Schultz, and B. E. Sheffy, 1981. Effect of vitamin E deficiency on the proliferative response of canine lymphocytes. Am. J. Vet. Res. 42:1681-1685. Larsen, H. J., and S. Tollersrud, 1981. Effect of dietary vitamin E and selenium on the phytohaemagglutinin response of pig lymphocytes. Res. Vet. Sci. 31:301-305. Likoff, R. O., D. R. Guptill, L. M. Lawrence, C. C. McKay, M. M. Mathias, C. F. Nockels, and R. P. Tengerdy, 1981. Vitamin E and aspirin depress prostaglandins in protection of chickens against E. coli infection. Am. J. Clin. Nutr. 35:245-251. Long, P. L., J. Johnson, and R. D. Wyatt, 1980. Eimeria tenella: Clinical effects in partially immune and susceptible chickens. Poultry Sci. 59:2221-2224. Marsh, J. A., R. R. Dietert, and G. F. Combs, Jr., 1981. Influence of dietary selenium and vitamin E on the humoral immune response of the chick. Proc. Soc. Exp. Biol. Med. 66:228-236. Marsh, J. A., R. R. Dietert, and G. F. Combs, Jr., 1982. Effects of dietary deficiencies of vitamin E and selenium on the primary lymphoid organs of the chick. Fed. Proc. 41:341. (Abstr.) Rose, M. E., and P. L. Long, 1962. Immunity to four species of Eimeria in fowl. Immunology 5: 79-92. Rose, M. E., 1973. Immunity. Pages 2 9 5 - 3 4 1 in The Coccidia: Eimeria, Isospora, Toxoplasma and Related Genera. D. M. Hammong and P. L. Long, ed. University Park, Baltimore, MD. Spallholz, J. E., J. L. Martin, M. L. Gerlach, and R. H. Heinzerling, 1973. Immunologic responses of mice fed diets supplemented with selenite selenium. Proc. Soc. Exp. Biol. Med. 143:685 — 689. Statistical Analysis System Institute, 1979. SAS User's Guide, ed. SAS Inst., Inc., Raleigh, NC. Tengerdy, R. P., Heinzerling, and C. F. Nockels, 1972. Effect of vitamin E on the immune response of hypoxic and normal chicks. Infect. Immun. 5:987-989. Tengerdy, R. P., R. H. Heinzerling, G. L. Brown, and M. M. Mathias, 1973. Enhancement of the humoral immune response by vitamin E. Int. Arch. Allergy 44:221-232. Tengerdy, R. P., and C. F. Nockels, 1975. Vitamin E or vitamin A protects chicks against E. coli infection. Poultry Sci. 54:1292-1296. Tengerdy, R. P., and J. C. Brown, 1977. Effect of vitamin E and A on humoral immunity and phagocytosis in £. coli infected chicken. Poultry Sci. 56:957-963. Whetter, P. A., and D. E. Ullrey, 1978. Improved fluorometric method for determining selenium. J. Assoc. Offic. Anal. Chem. 61:927-930.
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activity. Therefore, the leucocytes are retained at the site of infection, protecting the host against the pathogenic effects of the parasite. Selenium and vitamin E have also been shown to enhance the proliferative response of lymphocytes to mitogens (Langweiler et al, 1981; Larsen and Tollersrud, 1981) and antibody titers (Spallholz et al, 1973; Tengerdy and Nockels, 1975). Likoff et al. (1981) showed that supplementary vitamin E depressed prostaglandin levels in the immunopoietic organs of chickens. They suggested that the vitamin E enhancement of the immune response and the overall protection from infection is mediated through a reduction in synthesis of prostaglandins in infected chickens.
1143