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Effects of aureomycin and vitamin B12 used separately as feed supplements on resistance of chickens to Ascaridia galli (Schrank)
Effects of Aureomycin and Vitamin B12Used Separately as Feed Supplements on Resistance of Chickens to Ascaridia gdi (Schrank)’ M. F. Hansen,
Leo H. Petri2 and J. E. Ackert
Department of Zoology, Kansas State College, Manhattan, Kansas (Submitted
for publication,
10 April
1953)
Effects of aureomycin and vitamin Blz used in combination as a feed supplement on the resistance of chickens to the fowl ascarid, Ascaridia galli (Schrank), were investigated by Hansen, Xorris, and Ackert (1953). In the study the pertinent literature on diet and its relationship to host resistance to parasitism was presented. That study utilized a combination of aureomycin and vitamin B 123which was added to an all-plant protein basal ration complete with the necessary vitamins and minerals for good chick growth. The amount added gave a concentration of 0.9 g aureomycin and 0.9 mg vitamin Blz per 100 lb of basal ration. Chicks fed the supplemented ration showed a lower mortality and infection rate and harbored significantly fewer worms than did the chicks fed only the basal ration. Superior weight gains were made by those chicks fed the fortified diet. However, statistical treatment of weight gains of parasitized versus non-parasitized chicks fed only the basal ration showed no significant difference, whereas the difference in weight gains between the parasitized versus non-parasitized chicks fed the supplemented ration was significant. Accordingly, if poultrymen are to achieve maximum benefits in their flocks from feeds fortified with growth promoting substances, they must control ascarids in their flocks. The present study extends the work reported by Hansen et al. (ibid.) by establishing the roles of the supplements, aureomycin and vitamin Blz , used separately in the resistance of chicks to the fowl ascarid. 1 Contribution No. 250 from the Kansas Agricultural Experiment Station in the Department of Zoology and No. 293 from the Department of Zoology, Kansas State College. 2 Department of Biology, Wartburg College, Waverly, Iowa. 3 Aureomycin hydrochloride, vitamin Biz (Profactor B), and aureomycin-vitamin B12 (Aurofac) were supplied by the American Cyanamid Company, Lederle Laboratories Division, Pearl River, New York. 122
AUREOMYCIN, B12 AND RESISTANCE TO A. GALL1 MATERIALS
123
AND METHODS
The chicks used in this study were non-sexed White Plymouth Rocks purchased from an approved commercial hatchery. They were banded, weighed, and divided into experimental groups of very nearly equal weight according to the method described by Gardiner and Wehr (1950). In the first experiment six groups were established. In the second experiment eight groups were used because of the advisability of using a parasitized and non-parasitized group whose basal ration was supplemented with a combination of the antibiotic and the vitamin. The chicks were started on their experimental diets the day they were received and kept on their respective diets until the experiments were terminated 21 days subsequent to feeding half of the chicks embryonated eggs of A. galli. Weightsof individual chicks were taken each week. An all-plant protein basal ration, complete with the necessary vitamins and minerals for good chick growth, was obtained for use in the experiments from the Kansas State College Poultry Farm. This basal ration was modified so that four diets were established (Table I). Chicks in Groups 1 and 2 were fed only the basal ration. Those in Groups 3 and 4 received 0.9 g aureomycin hydrochloride per 100 lb of basal ration, and the chicks in Groups 5 and 6 received the basal ration which contained 0.9 mg vitamin Blz per 100 lb of feed. The chicks in Groups 7 and 8 received a combination of aureomycin (0.9 g/100 lb feed) and vitamin 1312(0.9 mg/lOO lb feed). St 14 days of age the chicks in Groups 2,4,6, and 8 were given 100 i 10 embryonsted eggs of A. galli per OSand were sacrificed 21 days subsequently. The worms were recovered from the intestine of each infected chick by the method used in a previous study (Hansen et al., i&d). The numbers of worms and the length of each worm were recorded. Measurements were made with the aid of a view-camera and a Dietzgen Map Measure Tool. RESULTS
The combined results of two experiments are recorded in Table I. The type of diet as well as the presence of ascarids influenced the mortality rates, and the t,ype of diet also influenced the infection rates among the chicks in the various groups. The most deaths occurred among the parasitized chicks fed only the basal ration (Group 2). No deaths were recorded among the chicks fed the supplemented basal ration, irrespective of whether they were parasitized. The highest incidence of infection was recorded for the chicks in Group 2; the lowest incidence of infection occurred among the chicks in Group 6. No laboratory diagnoses were made to ascertain the cause of death among the chicks in Group 2; however, the data indicated that ascariasis was a contributing factor. The data on mortality and incidence of infection showed that the supplements, whether used independently or in combination with one another, afforded some protection. The greatest pro-
124
M.
The Efects
F.
HANSEN,
L.
H.
PETRI
AND
TABLE I Basal Rationa Aureomycin and VitaminBlz Supplements of an All-Plant
Experimental groups
Basal Basal + ascarid eggs Aureomycin Aureomycin $ ascarid eggs Blz Blz + ascarid eggs Aurofac Aurofac + ascarid eggs
J. E.
ACKERT
Protein
and Various Combinations on Fowl Ascariasis
Chicks
WOlT!lS
-No. mrt.AV.90b fected Av. inAv. wt. % gain (pm) :Ilwd-1:
Feed fficiency
Av. No er chic
k’ 4vi3h
1.3 3.7
-
64.5
286.0
2.3 2.3
-
77
2.9
9.22
81 80
0.0 0.0
47.5
308.4 299.7
2.3 2.3
1.1
7.05
80 79
0.0 0.0
26.5
296.4 301.9
2.4 2.3
1.2
14.62
19 19
0.0 0.0
31.0
366.8 336.0
2.3 2.5
0.8
10.80
77
-
289.6
-
of
-
-
’ Basal ration fed to all 8 groups of chicks. ’ Baaed upon deaths occurring among chicks subsequent to feeding A. g&i eggs.
tection against infection with A. galli was given by the vitamin B12 supplement. Diet and the presence of ascarids influenced weight gains made by the chicks in the different experimental groups (Table I). Statistical analyses were made of the differences in weight gains made between the following categories of chicks in the various experimental groups; (1) parasitized versus non-parasitized controls, (2) non-parasitized, and (3) parasitized. The results of the analyses of the first category revealed significant differences only between Groups 7 and 8. Differences in weight gains made by the chicks in the second category showed that those chicks fed the aureomycin-vitamin Blz combined (Group 7) made weight gains superior to any of the other groups of chicks. With the exception of the weight gains made by the chicks in Group 1 versus Group 5, and Group 3 versus Group 5 all other combinations of experimental groups in this category showed statistically significant differences in gains in weight. Analyses of the weight gains of the various combinations of experimental groups in the third category, parasitized, revealed differences in all of the group combinations except Group 2 versus Group 4, and Group 4 versus Group 6. The analyses of the weight gains made by the various
AUREOMYCIN,
B12 AND
RESISTANCE
TO
A.
GALL1
125
experimental groups of chicks indicate that vitamin B~zand a combination of aureomycin-vitamin Blz were effective in modifying the growth retarding effects of the ascarid infection. However, the presence of ascarids among the chicks fed t,he aureomycin-vitamin B1, supplement significantly retarded their growth as compared with their non-parasitized controls fed the same supplement. There was very little difference in feed efficiency, as calculated on a chick-JJ-eekbasis, between the various diets used in the experiments (Table I). The feed efficiencies of 2.3 and 2.5 shown by the diets fed to the chicks in Groups 7 and 8, respectively, indicated a possible decrease in feed efficiency due to the ascarids harbored by t,he chicks in Group 8. However, the following factors must be kept in mind when drawing conclusions concerning the data presented on feed efficiency; (1) the data cover only a period of growth of the chicks up to five weeks of age, and (2) the basal ration purposely was made deficient in animal protein so as to eliminate that source of vitamin Bit , thus, these results are not to be compared strictly with those results obtained from commercial rations. It would appear to be worthwhile to investigate further t.he influence of parasitism on feed efficiency of diets containing growth promoting substances. An average number of 1.1, 1.2, and 0.8 worms per chick was recovered from Groups 4, 6, and 8, respectively. Statistical analyses revealed no significant differences between the numbers of worms recovered from these three groups of chicks. The chicks in Group 2 harbored an average of 2.9 worms per chick which proved to be a significantly larger number of worms than those obtained from any of the other parasitized groups. Thus, the aureomycin and/or vitamin B12affected the degree of parasitosis among the infected chicks. Some statistically significant differences in the average lengths of the worms recovered from the four parasitized groups were observed. The shortest worms, measuring an average of 7.05 mm, were recovered from Group 4. The difference in average length between the worms of Groups 2 and 4 was significant at the 1% level. The longest worms recovered, measuring an average of 14.62 mm, were from Group 6. The difference in lengths of these worms, as compared with the worm lengths obtained from any of the other parasitized groups, proved to be statistically significant. There were no statistically significant differences between the lengths of worms recovered from Groups 2 and 8. This result on worm lengths corroborates the previous findings of Hansen et al. (ibid.), who
126
M.
F.
HANSEN,
L.
H.
PETRI
AND
S. E.
ACKERT
likewise reported no differences in growth rates of worms recovered from chicks fed the basal ration or the ration supplemented with both aureomycin and vitamin Bi2 . DISCUSSION
At the present time, there is a tendency for poultrymen and farmers, often on professional advice, to ignore ascariasis in their flocks. Such ideas can very easily stem from the insidious nature of parasitosis. If no spectacular symptoms or great mortality rates occur among their parasitized flocks, it is very easy to come to the conclusion that this parasite should be of no concern. Small but significant retardations in the growth rate of parasitized chicks go unrecognized, thus, A. galli and other types of internal parasites exact an annual toll from poultrymen by retarding the growth rates of their chicks. Retarded growth rates mean that the farmer is unable to obtain optimum market weight in the shortest possible time on the least amount of feed. The results of this study and that, reported by Hansen et al. (ibid.) clearly indicate hole modern poultry nutrition, in conjunction with the use of antibiotics and vitamin supplements to stimulate growth, may serve to ameliorate the effects of parasitosis. However, these studies also have demonstrated the importance of t’he control of ascariasis, if masimum growth responses are to be gained from such fortified feeds. Aureomycin and vitamin I312, whether t)heir action is considered independently or in combination with each other, reduce t’he numbers of worms harbored by chicks. However, their separate effects on the vigor of the worms is different. hureomycin, at the level and with the type of basal ration used in this study, significantly rest’ricted t,he growth of the ascarids, whereas, vitamin Bl:! stimulated their growth. Growth stimulation of ascarids by vitamin B 12was noted by Sadun (1950). The presence of both aureomycin and vitamin B12 in t’he diet nullified their individual effects in that worms recovered from chicks fed the basal ration supplemented with the combination grew at, the same rate as those worms recovered from chicks fed only the basal ration. The vitamin B12 apparently restricts the numbers of parasites indirectly through increased host resistance, whereas, the aureomycin in addition t’o this indirect effect, conceivably could exert a direct action also. The worms in the presence of the aureomycin grew slowly thus indicating interference with their metabolism.
AUREOMYCIN, Bj2 AND RESISTANCE TO A. GALL1
127
SUMMARY 1. A total of 512 non-sexed White Rock chicks was divided into eight groups and all were fed an all-plant-protein basal diet. The ration for six of the groups was supplemented with aureomycin or vitamin BIZ , or a combination of both. Half of the chicks in each of the four diet groups were fed 100 f 10 embryonated eggs of A. galli in order to investigate the effects of the supplements in the diet on this fowl ascarid. 2. The highest mortality rate and incidence of infection occurred among the chicks fed only the basal ration, whereas, there were no deaths and a much lower incidence of infection among the chicks fed the supplemented basal ration. 3. The simultaneous use of aureomycin and vitamin BU significantly stimulated the growth of the chicks regardless of whether they were parasitized. However, in order to aid in obtaining additional growth responses from feeds fortified with these supplements, ascarids must be controlled. 4. Very small differences in feed efficiencies of the various diets was noted. There was some indication that ascariasis decreased the feed efficiency of the ration supplemented with a combination of aureomycin-vitamin B12 . 5. Whereas aureomycin and/or vitamin BIZ reduced the numbers of ascarids in the chicks, the aureomycin restricted the rate of growth of the ascarids and vitamin Blz stimulated their growth. When these supplements were used together their effects on the growth of the worms was nullified. REFERENCES GARDINER, J. L., AND WEHR, E. E. 1950. Selecting experimental groups of chicks by weight. Proc. Helminthol. Sot. Wash. D. C. 17, (l), 25-26. HANSEN, M. F., NORRIS, M. G., AND ACKERT, J. E. 1953. The influence of an all plant protein diet supplemented with aureomycin and vitamin Blj! on the resistance of chicks to Ascaridia galEi (Schrank). Poultry Sci. 32, (4),612417. SADUN, E.H.,KEITH,C. K., PANKEY, M.J., ANDToTTER,J.R.~~~O.T~~ influence of dietary pteroylglutamic acid and APA liver extract on the survival and growth of the nematode Ascaridia galli in chickens fed purified and natural diets. Am. J. Hyg. 61, 274-291.
Leo H. Petri2 and J. E. Ackert
Department of Zoology, Kansas State College, Manhattan, Kansas (Submitted
for publication,
10 April
1953)
Effects of aureomycin and vitamin Blz used in combination as a feed supplement on the resistance of chickens to the fowl ascarid, Ascaridia galli (Schrank), were investigated by Hansen, Xorris, and Ackert (1953). In the study the pertinent literature on diet and its relationship to host resistance to parasitism was presented. That study utilized a combination of aureomycin and vitamin B 123which was added to an all-plant protein basal ration complete with the necessary vitamins and minerals for good chick growth. The amount added gave a concentration of 0.9 g aureomycin and 0.9 mg vitamin Blz per 100 lb of basal ration. Chicks fed the supplemented ration showed a lower mortality and infection rate and harbored significantly fewer worms than did the chicks fed only the basal ration. Superior weight gains were made by those chicks fed the fortified diet. However, statistical treatment of weight gains of parasitized versus non-parasitized chicks fed only the basal ration showed no significant difference, whereas the difference in weight gains between the parasitized versus non-parasitized chicks fed the supplemented ration was significant. Accordingly, if poultrymen are to achieve maximum benefits in their flocks from feeds fortified with growth promoting substances, they must control ascarids in their flocks. The present study extends the work reported by Hansen et al. (ibid.) by establishing the roles of the supplements, aureomycin and vitamin Blz , used separately in the resistance of chicks to the fowl ascarid. 1 Contribution No. 250 from the Kansas Agricultural Experiment Station in the Department of Zoology and No. 293 from the Department of Zoology, Kansas State College. 2 Department of Biology, Wartburg College, Waverly, Iowa. 3 Aureomycin hydrochloride, vitamin Biz (Profactor B), and aureomycin-vitamin B12 (Aurofac) were supplied by the American Cyanamid Company, Lederle Laboratories Division, Pearl River, New York. 122
AUREOMYCIN, B12 AND RESISTANCE TO A. GALL1 MATERIALS
123
AND METHODS
The chicks used in this study were non-sexed White Plymouth Rocks purchased from an approved commercial hatchery. They were banded, weighed, and divided into experimental groups of very nearly equal weight according to the method described by Gardiner and Wehr (1950). In the first experiment six groups were established. In the second experiment eight groups were used because of the advisability of using a parasitized and non-parasitized group whose basal ration was supplemented with a combination of the antibiotic and the vitamin. The chicks were started on their experimental diets the day they were received and kept on their respective diets until the experiments were terminated 21 days subsequent to feeding half of the chicks embryonated eggs of A. galli. Weightsof individual chicks were taken each week. An all-plant protein basal ration, complete with the necessary vitamins and minerals for good chick growth, was obtained for use in the experiments from the Kansas State College Poultry Farm. This basal ration was modified so that four diets were established (Table I). Chicks in Groups 1 and 2 were fed only the basal ration. Those in Groups 3 and 4 received 0.9 g aureomycin hydrochloride per 100 lb of basal ration, and the chicks in Groups 5 and 6 received the basal ration which contained 0.9 mg vitamin Blz per 100 lb of feed. The chicks in Groups 7 and 8 received a combination of aureomycin (0.9 g/100 lb feed) and vitamin 1312(0.9 mg/lOO lb feed). St 14 days of age the chicks in Groups 2,4,6, and 8 were given 100 i 10 embryonsted eggs of A. galli per OSand were sacrificed 21 days subsequently. The worms were recovered from the intestine of each infected chick by the method used in a previous study (Hansen et al., i&d). The numbers of worms and the length of each worm were recorded. Measurements were made with the aid of a view-camera and a Dietzgen Map Measure Tool. RESULTS
The combined results of two experiments are recorded in Table I. The type of diet as well as the presence of ascarids influenced the mortality rates, and the t,ype of diet also influenced the infection rates among the chicks in the various groups. The most deaths occurred among the parasitized chicks fed only the basal ration (Group 2). No deaths were recorded among the chicks fed the supplemented basal ration, irrespective of whether they were parasitized. The highest incidence of infection was recorded for the chicks in Group 2; the lowest incidence of infection occurred among the chicks in Group 6. No laboratory diagnoses were made to ascertain the cause of death among the chicks in Group 2; however, the data indicated that ascariasis was a contributing factor. The data on mortality and incidence of infection showed that the supplements, whether used independently or in combination with one another, afforded some protection. The greatest pro-
124
M.
The Efects
F.
HANSEN,
L.
H.
PETRI
AND
TABLE I Basal Rationa Aureomycin and VitaminBlz Supplements of an All-Plant
Experimental groups
Basal Basal + ascarid eggs Aureomycin Aureomycin $ ascarid eggs Blz Blz + ascarid eggs Aurofac Aurofac + ascarid eggs
J. E.
ACKERT
Protein
and Various Combinations on Fowl Ascariasis
Chicks
WOlT!lS
-No. mrt.AV.90b fected Av. inAv. wt. % gain (pm) :Ilwd-1:
Feed fficiency
Av. No er chic
k’ 4vi3h
1.3 3.7
-
64.5
286.0
2.3 2.3
-
77
2.9
9.22
81 80
0.0 0.0
47.5
308.4 299.7
2.3 2.3
1.1
7.05
80 79
0.0 0.0
26.5
296.4 301.9
2.4 2.3
1.2
14.62
19 19
0.0 0.0
31.0
366.8 336.0
2.3 2.5
0.8
10.80
77
-
289.6
-
of
-
-
’ Basal ration fed to all 8 groups of chicks. ’ Baaed upon deaths occurring among chicks subsequent to feeding A. g&i eggs.
tection against infection with A. galli was given by the vitamin B12 supplement. Diet and the presence of ascarids influenced weight gains made by the chicks in the different experimental groups (Table I). Statistical analyses were made of the differences in weight gains made between the following categories of chicks in the various experimental groups; (1) parasitized versus non-parasitized controls, (2) non-parasitized, and (3) parasitized. The results of the analyses of the first category revealed significant differences only between Groups 7 and 8. Differences in weight gains made by the chicks in the second category showed that those chicks fed the aureomycin-vitamin Blz combined (Group 7) made weight gains superior to any of the other groups of chicks. With the exception of the weight gains made by the chicks in Group 1 versus Group 5, and Group 3 versus Group 5 all other combinations of experimental groups in this category showed statistically significant differences in gains in weight. Analyses of the weight gains of the various combinations of experimental groups in the third category, parasitized, revealed differences in all of the group combinations except Group 2 versus Group 4, and Group 4 versus Group 6. The analyses of the weight gains made by the various
AUREOMYCIN,
B12 AND
RESISTANCE
TO
A.
GALL1
125
experimental groups of chicks indicate that vitamin B~zand a combination of aureomycin-vitamin Blz were effective in modifying the growth retarding effects of the ascarid infection. However, the presence of ascarids among the chicks fed t,he aureomycin-vitamin B1, supplement significantly retarded their growth as compared with their non-parasitized controls fed the same supplement. There was very little difference in feed efficiency, as calculated on a chick-JJ-eekbasis, between the various diets used in the experiments (Table I). The feed efficiencies of 2.3 and 2.5 shown by the diets fed to the chicks in Groups 7 and 8, respectively, indicated a possible decrease in feed efficiency due to the ascarids harbored by t,he chicks in Group 8. However, the following factors must be kept in mind when drawing conclusions concerning the data presented on feed efficiency; (1) the data cover only a period of growth of the chicks up to five weeks of age, and (2) the basal ration purposely was made deficient in animal protein so as to eliminate that source of vitamin Bit , thus, these results are not to be compared strictly with those results obtained from commercial rations. It would appear to be worthwhile to investigate further t.he influence of parasitism on feed efficiency of diets containing growth promoting substances. An average number of 1.1, 1.2, and 0.8 worms per chick was recovered from Groups 4, 6, and 8, respectively. Statistical analyses revealed no significant differences between the numbers of worms recovered from these three groups of chicks. The chicks in Group 2 harbored an average of 2.9 worms per chick which proved to be a significantly larger number of worms than those obtained from any of the other parasitized groups. Thus, the aureomycin and/or vitamin B12affected the degree of parasitosis among the infected chicks. Some statistically significant differences in the average lengths of the worms recovered from the four parasitized groups were observed. The shortest worms, measuring an average of 7.05 mm, were recovered from Group 4. The difference in average length between the worms of Groups 2 and 4 was significant at the 1% level. The longest worms recovered, measuring an average of 14.62 mm, were from Group 6. The difference in lengths of these worms, as compared with the worm lengths obtained from any of the other parasitized groups, proved to be statistically significant. There were no statistically significant differences between the lengths of worms recovered from Groups 2 and 8. This result on worm lengths corroborates the previous findings of Hansen et al. (ibid.), who
126
M.
F.
HANSEN,
L.
H.
PETRI
AND
S. E.
ACKERT
likewise reported no differences in growth rates of worms recovered from chicks fed the basal ration or the ration supplemented with both aureomycin and vitamin Bi2 . DISCUSSION
At the present time, there is a tendency for poultrymen and farmers, often on professional advice, to ignore ascariasis in their flocks. Such ideas can very easily stem from the insidious nature of parasitosis. If no spectacular symptoms or great mortality rates occur among their parasitized flocks, it is very easy to come to the conclusion that this parasite should be of no concern. Small but significant retardations in the growth rate of parasitized chicks go unrecognized, thus, A. galli and other types of internal parasites exact an annual toll from poultrymen by retarding the growth rates of their chicks. Retarded growth rates mean that the farmer is unable to obtain optimum market weight in the shortest possible time on the least amount of feed. The results of this study and that, reported by Hansen et al. (ibid.) clearly indicate hole modern poultry nutrition, in conjunction with the use of antibiotics and vitamin supplements to stimulate growth, may serve to ameliorate the effects of parasitosis. However, these studies also have demonstrated the importance of t’he control of ascariasis, if masimum growth responses are to be gained from such fortified feeds. Aureomycin and vitamin I312, whether t)heir action is considered independently or in combination with each other, reduce t’he numbers of worms harbored by chicks. However, their separate effects on the vigor of the worms is different. hureomycin, at the level and with the type of basal ration used in this study, significantly rest’ricted t,he growth of the ascarids, whereas, vitamin Bl:! stimulated their growth. Growth stimulation of ascarids by vitamin B 12was noted by Sadun (1950). The presence of both aureomycin and vitamin B12 in t’he diet nullified their individual effects in that worms recovered from chicks fed the basal ration supplemented with the combination grew at, the same rate as those worms recovered from chicks fed only the basal ration. The vitamin B12 apparently restricts the numbers of parasites indirectly through increased host resistance, whereas, the aureomycin in addition t’o this indirect effect, conceivably could exert a direct action also. The worms in the presence of the aureomycin grew slowly thus indicating interference with their metabolism.
AUREOMYCIN, Bj2 AND RESISTANCE TO A. GALL1
127
SUMMARY 1. A total of 512 non-sexed White Rock chicks was divided into eight groups and all were fed an all-plant-protein basal diet. The ration for six of the groups was supplemented with aureomycin or vitamin BIZ , or a combination of both. Half of the chicks in each of the four diet groups were fed 100 f 10 embryonated eggs of A. galli in order to investigate the effects of the supplements in the diet on this fowl ascarid. 2. The highest mortality rate and incidence of infection occurred among the chicks fed only the basal ration, whereas, there were no deaths and a much lower incidence of infection among the chicks fed the supplemented basal ration. 3. The simultaneous use of aureomycin and vitamin BU significantly stimulated the growth of the chicks regardless of whether they were parasitized. However, in order to aid in obtaining additional growth responses from feeds fortified with these supplements, ascarids must be controlled. 4. Very small differences in feed efficiencies of the various diets was noted. There was some indication that ascariasis decreased the feed efficiency of the ration supplemented with a combination of aureomycin-vitamin B12 . 5. Whereas aureomycin and/or vitamin BIZ reduced the numbers of ascarids in the chicks, the aureomycin restricted the rate of growth of the ascarids and vitamin Blz stimulated their growth. When these supplements were used together their effects on the growth of the worms was nullified. REFERENCES GARDINER, J. L., AND WEHR, E. E. 1950. Selecting experimental groups of chicks by weight. Proc. Helminthol. Sot. Wash. D. C. 17, (l), 25-26. HANSEN, M. F., NORRIS, M. G., AND ACKERT, J. E. 1953. The influence of an all plant protein diet supplemented with aureomycin and vitamin Blj! on the resistance of chicks to Ascaridia galEi (Schrank). Poultry Sci. 32, (4),612417. SADUN, E.H.,KEITH,C. K., PANKEY, M.J., ANDToTTER,J.R.~~~O.T~~ influence of dietary pteroylglutamic acid and APA liver extract on the survival and growth of the nematode Ascaridia galli in chickens fed purified and natural diets. Am. J. Hyg. 61, 274-291.