ARSANILIC ACID AS A THERAPEUTIC AND PROPHYLACTIC AGENT FOR HEMORRHAGIC DYSENTERY

Transcription

1 ARSANILIC ACID AS A THERAPEUTIC AND PROPHYLACTIC AGENT FOR HEMORRHAGIC DYSENTERY I. D. SMITH, E. M. KIGGINS, H. S. PERDUE, J. C. HOLPER AND D. V. FROST 1 EMORRHAGIC dysentery--long an H enigma to the swine grower, veterinarian, and research worker--still exacts heavy financial losses. Doyle (1959) gives a complete description of the disease complex. It is essentially a catarrhal enteritis involving the cecum and the colon, characterized by the passage of mucus and blood. The stomach may be hyperemic. Generally there is little or no febrile response. In contrast, pigs suffering from a Salmonella choleraesuis infection have little blood in the stools. In the latter the entire intestinal tract is often involved, including the small intestine, and there is usually a marked febrile response. Sodium arsanilate added to the drinking water has been shown to be an effective therapeutic agent for hemorrhagic dysentery (Boley et al., 1951 ; Langham et al., 1952 ; Rosoff and Abel, 1953). Preliminary reports (Patrias 1952, 1953) have indicated a similar value for arsanilic acid when it is included in the feed. The positive effects of various arsonic acids in an experimental herd was ascribed by Carpenter (1951) and by Carpenter and Larson (1952) partly to control hemorrhagic dysentery. Lubbehusen (1956) has succinctly stated the case for a medicated feed service program. The addition of arsanilic acid to the feed provides a sure, and possibly more convenient, way of regulating the dosage rate as compared with the addition of sodium arsanilate to the drinking water. This is important when one considers the relatively narrow tolerance range of swine for arsanilic acid (Frost and Spruth, 1956). Furthermore, appetite is not as severely affected in pigs suffering from hemorrhagic dysentery as it is in some enteritic conditions. Thus, water medication is not obligatory. The purpose of this investigation was to test the effects of adding graded levels of 1 The authors are grateful to. K. M. Prinz for his aid in the necropsy of animals in one of the experiments. 2 Nutrition Research Department and Department of Infectious Disease. Abbott Laboratories, North Chicago, Illinois arsanilic acid to the feed of swine suffering with hemorrhagic dysentery. Experimental The basal diets used in all the experiments are given in table 1. Diet 1 contained 16% protein and was fed from the start of the experiments until the pigs weighed 100 to 125 lb., when Diet 2 containing 12% protein was used. The required amount of arsanilic acid (AA) was added as a 20% premix in soybean oil meal. 3 Sodium arsanilate (NaA) was provided in the form of tablets which contained 668 rag. of NaA, the sodium salt of AA. The addition of one tablet per gallon of water provided 175 ppm NaA, which is equivalent to 160 ppm AA. The tablets were dissolved in a small amount of warm water to insure their complete dissolution before adding them to the main water supply. The NaA was alternately provided for 5 days and then withdrawn for 2 days for the duration of the experiment. The animals prior to the initiation of the test had been vaccinated for cholera and erysipelas. Animals which died were necropsled with special attention being given to signs of gastroenteritis. Also smears and/or cultures were taken from the intestinal tract to determine the presence or absence of Vibrio coli. The data were analyzed by analysis of variance. Experiment I. Following an outbreak of hemorrhagic dysentery, 80 pigs weighing approximately 140 lb. were formed into outcome groups on the bases of their average daily gain during the preceding week, incidence of scouring and body weight. Animals were then allotted at random from these outcome groups to the following treatments: Basal (B), B plus 100 ppm AA, B plus 200 ppm AA, B plus 250 ppm AA, and B plus 175 ppm NaA in the drinking water. These treatments were replicated once. The pigs were weighed weekly and observed individually until they defecated to Pro-Gen, 20%, Abbott Laboratories, North Chicago, Illinois.

2 ARSANILIC ACID FOR HEMORRHAGIC DYSENTERY determine if they were or were not scouting. Feed consumption also was recorded. The experiment lasted 4 weeks. Experiment II. This study, like the previous one, was designed following an outbreak of hemorrhagic dysentery to study the therapeutic value of various dietary levels of arsanilic acid. In this experiment 97 pigs weighing approximately 75 lb. were placed on test using the same allotment procedure and treatments as those described for Experiment I, with the following exception. The animals which received the B plus 200 ppm AA and B plus 250 ppm AA received these diets for 4 weeks and then the basal diet alone for one week. This alternating procedure, 4 weeks' treatment and 1 week off the drug, TABLE 1. COMPOSITION OF BASAL DIETS '~ Percent Percent in diet in diet Ingredient no. 1 no. 2 Ground yellow corn Soybean oil meal Meat and bone scraps Dehydrated alfalfa meal Limestone Salt Vitamin and trace mineral mixture b IO I00.00'0 a Diet No. 1 fed until the pigs weighed between lb. and then Diet No. 2 was used. b Composition in grams per kg. choline chloride, 25.7; calcium-dl-pantothenate, 26.4; vitamin Ba2,.027; nicotinic acid, 24.5; riboflavin, 5.3; viosterol (1 x 106 I.U./gm.), 64; trace minerals (Calcium Carbonate Company, No. 244), 606; zinc oxide, 197." inert ingredients, was followed for the duration of the test, which lasted 11 weeks. Experiment III. To compare the effects of graded levels of arsanilic acid in the diet as prophylactic agents for hemorrhagic dysentery, 100 weanling pigs weighing between 40 to 50 lb. were used. The pigs were formed into outcome groups with reference to body weight, sex and breeding and then allotted at random from these groups to the experimental treatments. The treatments were as follows: Basal (B); B plus 100 ppm AA; B plus 200 ppm AA; B plus 250 ppm AA. Twenty pigs were assigned to each treatment with the exception of the basal which had 40 pigs divided between two lots containing 20 pigs each. This experiment was conducted on pasture in contrast to Experiments I and II, which were conducted on drylot. Half of the pigs from each treatment (i.e pigs) were orally challenged with a milk suspension of homogenized gastrointestinal tracts from pigs suffering with hemorrhagic dysentery, and from which viable Vibrio coli was isolated. The remaining half were exposed to the infection by housing them with the orally challenged animals. The milk suspension was prepared by homogenizing the entire gastrointestinal tracts and their contents from three pigs using a Waring Blendor. The homogenate was added to 15 gal. of milk, which was divided equally among the groups. Pigs were weighed weekly, feed consumption determined and the pens checked for the presence of bloody scours. Results and Discussion Experiment I. Table 2 contains a summary of the data for this experiment. Though all groups showed some improvement in average daily gain, the groups receiving AA had the highest values, followed by the group receiving NaA. Statistical analysis of the growth data showed the difference between the controls and groups receiving AA to be close to the 5% level of significance. There was essentially no difference in the gains made among the 3 different levels of AA. The data for feed efficiency also show an improvement for the treated groups with the group receiving 250 ppm AA showing most improvement. It is perhaps worthy of note here that no pigs which received AA or NaA were scouring at the end of the experiment, whereas two pigs were scouring in the control lot. A comparison of the average daily gains for the control lot at the start and end of the experiment suggests these animals recovered spontaneously from the disease. This agrees with the general concept that hemorrhagic dysentery is to a degree self-eliminating and cyclic in character. In further support of this contention is the fact that 24 pigs out of 120 in the group died from hemorrhagic dysentery prior to the start of this test. Only one pig died during the experiment. Experiment II. This experiment was similar to Experiment I, with the exception that the treatment duration of the two highest levels of AA was varied. Results are given in table 3. In this experiment the additions of AA at 200 or 250 ppm of the diet or 175 ppm of NaA in the water resulted in a significant increase in average daily gain (P<0.01). While the

3 770 SMITH, ET AL. TABLE 2. EFFECTS OF ARSANILIC ACID OR ITS SODIUM SALT AS THERAPEUTIC AGENTS FOR HEMORRHAGIC DYSENTERY, EXPERIMENT I Lot no. 3 and 12 1 and 9 6 and 8 5 and 7 4 and 11 Basal+100 Basal+200 Basal+250 Basal+175 ppm Treatment a Basal ppm of AA ppm of AA ppm of AA NaA in the water b No. of pigs Av. body wt., lb. Start End Av. daily gain, lb. Preexperimental c Experimental period Av. daily feed intake, lb Feed/lb. gain, lb Number scouring Start End Mortality a Duration of the experiment was 4 weeks. u Alternately provided for 5 days and withdrawn for 2 days during the duration of the experiment. 175 ppm of NaA equivalent to 160 ppm of AA. c Average daily gain for a 1-week period prior to the start of the experiment. effect of AA at 100 ppm was not as marked in this test as in Experiment I, there was still some response in average daily gain. There appeared to be above normal feed wastage during this test; thus the data for feed efficiency may be in error. The mortality rate in Experiment li is markedly greater than that for Experiment I. In Experiment I the animals were not started on therapy until several weeks after the initial symptoms of hemorrhagic dysentery were observed. In Experiment II they were started on test two days after the initial symptoms were observed. There were no death losses in the groups of pigs which received 250 ppm AA in the feed or 175 ppm NaA in the water; whereas there was a 30% mortality rate in the basal group, 25% in the group receiving 100 ppm AA, and 20% in the group receiving 200 ppm AA. Pigs were not checked individually for scours in this test, but rather the pens were checked each weigh day. The most profuse scouring occurred during the first 4 weeks of the experiment. The lots receiving either 175 ppm NaA in the water or 250 ppm AA in the feed showed the earliest remissions. However, during the remaining 7 weeks evidence of bloody scours was seen sporadically among all the treatment groups as well as the controls. Experiment III. The results of this test are presented in table 4. The method of infection, i.e. either by oral challenge or contact, TABLE 3. EFFECT OF ARSANILIC ACID GIVEN FOR VARIOUS TIME PERIODS OR ITS SODIUM SALT AS THERAPEUTIC AGENTS FOR HEMORRHAGIC DYSENTERY, EXPERIMENT II Lot no. 2 and 11 6 and 8 1 and 9 5 and 12 4 and 7 Basal+100 Basal+200 b Basal+250 b Basal+IT5 ppmc Treatments ~ Basal ppm of AA ppm of AA ppm of AA NaA in the water No. of pigs Av. body wt., lb. Start End Av. daily gain, lb. Preexperimental a Experimental period * 1.54 * 1.61 e Av. daily feed intake, lb. 4.0, Feed/lb. gain, lb Mortality a Experiment lasted for 11 weeks. b Alternately provided for 4 weeks and withdrawn for 1 week during the experiment. e Alternately provided for 5 days and withdrawn for 2 days during the experiment. 175 ppm NaA equivalent to 160 ppm AA. a Average daily gains far a 1-month period prior to the start of the experiment. Significantly greater than the basal lot and the basal +100 ppm AA (P<0.01). f Significantly greater than the basal lot (P~0.01).

4 ARSANILIC ACID FOR HEMORRHAGIC DYSENTERY 771 TABLE 4. THE USE OF ARSANILIC ACID AS A PROPHYLACTIC AGENT IN HEMORRHAGIC DYSENTERY, EXPERIMENT III Lot No Basal-~-100 Basal-k200 Basalt-250 Treatmenff Basal Basal ppm of AA ppm of AA ppm of AA Number of pigs Av. body wt., lb. Start End Av. daily gain, lb. Orally challenged Contact challenged Av Av. daily feed intake, lb Feed/lb. gain, lb Mortality a Experiment lasted for 11 weeks. did not appear to affect weight gains or mortality. For purposes of discussion the data for the two methods of infection are averaged. In this test the addition of 100 ppm AA to the diet did not increase weight gains or feed efficiency. Although dietary additions of 200 ppm or 250 ppm AA appeared to improve weight gains and feed efficiency, statistical analysis of the data did not show these differences to be significant (P>0.05). The mortality rate was lower in the two groups receiving 200 ppm AA or 250 ppm AA. The one fatality which occurred in the group receiving 250 ppm AA did not exhibit the typical pathology associated with hemorrhagic dysentery, nor was Vibrio coli found in smears taken from the gastrointestinal tract. On each weigh-day the lots were carefully observed for the presence or absence of scours. Some scouring was observed in all lots. But the greatest incidence of scours and the only bloody scours occurred in the control lots and in the lot receiving 100 ppm AA. Average feed consumption expressed as a percent of body weight is given in table 5. The data from all three experiments are presented. In Experiments I and III there was little difference between the groups. This is not considered an atypical finding in pigs suffering from dysentery. However, pigs suffering with enteritis in which there is a febrile response, such as in Salmonellosis, generally show marked depression in appetite. The results of Experiment II show some depression in feed intake for the control group, but among the remaining groups there was little difference. In comparing the feed consumption figures from all three experiments with values given by the NRC, it appears that overall feed consumption was slightly depressed. Weight gains for the lots receiving 200 ppm or 250 ppm AA, or 175 ppm NaA were, however, about average. Vibrio coli was isolated in all experiments from necropsied animals which showed gastrointestinal lesions typical of hemorrhagic dysentery. Early evidence for the etiological role of Vibrio coli in hemorrhagic dysentery was advanced by Doyle (1944). Subsequently, others have reported the presence of Vibrio coli in the intestinal tracts of pigs suffering from hemorrhagic dysentery (Boley et al., 1951; Carpenter and Larson, 1952; Deas, 1960; Langham et al., 1952; Roberts, 1956a). Doyle (1948) and Roberts (1956a, b) reported that feeding pure cultures of Vibrio coli, protected with gastric mucin, produced swine dysentery. Others have not produced the disease by feeding pure cultures but have succeeded in causing hemorrhagic dysentery when the gastrointestinal tracts of diseased pigs were fed to healthy ones (Boley et al., TABLE 5. AVERAGE DAILY FEED CONSUMPTION EXPRESSED AS A PERCENT OF BODY WEIGHT Basalq-100 Basalq-200 Basalq-250 Basal-l-IT5 ppm Treatment Basal ppm of AA ppm of AA ppm of AA NaA in the water Experiment I Experiment II Experiment III 4.21 ~ Average of two basal lots.

5 772 SMITH, ET AL A,,,::.:----,., i. \ / \ F- 1.5,f,/// 1.4 / / /..., i~j /,~ A D 1.3 / ~...rr / ; 1.2,.,./..".I," v,,.o e 0.9 \D',, b.,4 / /D A o.8 o\,,,~ i o.? \ o', ~ / /D 0.6 \D",, / / 0.5 \ -//D / CONTROL NI 0.4 ~ V / 0.01% ARSANILIC ACID ~ /~ 0.02% ARSANILIC ACID 0.1 ~ ~ 0.025"/o ARSANILIC ACID g 0 O. I ~ \/ % SODIUM ARSANILATE IN WATER D = DEATHS I I I I I I I I I I I I I 0 I I0 II WEEKS Figure 1. Average daily gain by weekly periods and time death occurred for pigs in Experiment II. Values represent the average daily gains for only those pigs surviving at each one-week interval. 1951; Deas, 1960; unpublished data, Kiggins, 1960). Reports by Carpenter and Larson (1952), Larson and Carpenter (1953), Doyle (1948), Deas (1960), and Roberts (personal communication, 1960) indicate that Vibrio coli is a normal inhabitant of the pig's colon. This suggests that some other factor plays a role in the etiology of hemorrhagic dysentery. A possible role for spirochetes has been suggested (Carpenter and Larson, 1952). It is also possible that a virus has an etiological role in this disease. In figure 1 the average daily gain by weekly periods for those pigs in Experiment II are given. This is typical of the type of response observed in all experiments. The graph suggests that the difference in weight gain among the groups, as reported in the tables, resulted from the therapeutic effect of AA or NaA early in the experiment. Illustrated, also, is the marked mortality in the control group and the group receiving 100 ppm AA and the absence of mortality in the groups receiving 250 ppm AA or 175 ppm NaA. Evidence presented in this paper indicates that untreated pigs, which survive the initial stages of hemorrhagic dysentery, appear to recover spontaneously. A possible role of arsanilic acid in the initial stages may be disease inhibition until the pig develops immunity. Certainly, in these experiments arsanilic acid appeared to have its most pronounced effect in the initial stages of the disease. The role of coccidiostats to suppress the disease, thus

6 ARSANILIC ACID FOR HEMORRHAGIC DYSENTERY 773 permitting chickens to develop immunity to coccidiosis, has long been recognized. Obviously more research is needed to determine if such factors are operational in swine hemorrhagic dysentery. Some investigators have observed evidence of toxicity in pigs fed arsanilic acid at 200 ppm of the diet from weaning to market (Frost et al., 1955; Notzold et al., 1956). It is noteworthy that in none of these experiments did any of the pigs exhibit signs of toxicity, even when fed arsanilic acid at 250 ppm of the diet for 11 weeks. Summary Data are presented from 3 experiments involving 277 pigs which were infected with hemorrhagic dysentery either through a natural outbreak or artificially. The treatment of this disease with 100 ppm arsanilic acid (AA), 200 ppm AA, or 250 ppm AA in the feed or 175 ppm sodium arsanilate (NaA) in the drinking water resulted in varying degrees of remission. In this series of tests 250 ppm AA in the feed or 175 ppm NaA in the water were the most effective in reducing the incidence of scours, lowering mortality, improving weight gains and improving feed efficiency. Feed consumption, while slightly lowered, was not sufficiently so as to preclude this medium as a route for medication. Literature Cited Boley, L. E., G. T. Woods, R. D. Hatch and R. Graham Studies on porcine enteritis II. Experimental therapy with sulfathalidine, sulfamethazine, sodium arsanilate and bacitracin in a natural outbreak of swine dysentery. Cornell Vet 41:231. Carpenter, L. E The effect of 3-nitro-4- hydroxy phenyl arsonic acid on the growth of swine. Arch. Biochem. Biophys. 32:181. Carpenter, L. E. and N. L. Larson Swine dysentery. Treatment with 4-nitro and 3-nitro-4- hydroxy phenyl arsonic acids and antibiotics. J. Animal Sci. 11:282. Deas, D. W Observations on swine dysentery and associated vibrios. Vet. Record 72:65. Doyle, L. P A vibrio associated with swine dysentery. Am. J. Vet. Res. 5:3. Doyle, L. P The etiology of swine dysentery. Am. J. Vet. Res. 9:50. Doyle, L. P Dysentery. In Diseases of Swine, (H. W. Dunne, ed.) Iowa State University Press, Ames, Iowa. Frost, D. V., L. R. Overby and H. C. Spruth Studies with arsanilic acid and related compounds. J. Agr. Food Chem. 3:235. Frost, D. V. and H. C. Spruth Arsenicals in Feeds. In Symposium on Medicated Feeds. Medical Encyclopedia, Inc., New York, New York. p Langham, R. F., R. Johnston, F. Tborp and J. Ritchie Swine dysentery. Michigan State College Vet. 12:71. Larson, N. L. and L. E. Carpenter Studies on swine dysentery. The Hormel Institute Annual Report p. 61. Lubbehusen, R. E Medicated feeds, some general comments. In Symposium on Medicated Feeds, (H. Welch and F. Marti-Ib~fiez, ed.). Medical Encyclopedia, Inc., New York, New York. p. 9. Notzold, R. A., D. E. Becker, F. B. Adamstone, S. W. Terrill and A. H. Jensen The tolerance of swine to dietary levels of P-aminophenylarsonic acid. J. Animal Sci. 15:1234 (Abstr.). Patrias, G The use of arsonic compounds in practical feeding tests. Feed Age 2:32. Patrias, G Role of arsonics in animal feed. Proc. A.F.M.A. Nutrition Council p. 16. Roberts, D. S. 1956a. Vibrionic dysentery in swine. The isolation of a vibrio from an outbreak in New South Wales. AUstralian Vet. J. 32:27. Roberts, D. S. 1956b. Studies on vibrionic ~tysentery in swine. Australian Vet. J. 32:114. Rosoff, I. S. and W. Abel Bacitracin: Its Use in control and treatment of swine enteritis. Vet. Med. 48:369.