Centenary biographical note: James E. Ackert.
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History, 20th Century↗
Biomedical subjects
W M Reid
Publications and source records attributed to W M Reid.
Practical immunization of chickens against coccidiosis using an attenuated strain of Eimeria tenella.
Three floor-pen trials were conducted to compare two attenuated strains of Eimeria tenella (Wis-F-96 and Wis-F-125) with the strain of E. tenella used in a commercial planned immunization program (Coccivac). Broiler cockerels were started in floor pens on new pine shavings litter. Immunizing oocysts were administered in the drinking water during the first week with total dose per bird of 175 oocysts of the control strain (Coccivac); 175, 350, or 700 oocysts of the Wis-F-125; 350 oocysts of Wis-F-96; or no oocysts (non-seeded control). The control strain was more pathogenic than the Wis-F-125 or the Wis-F-96 strains as indicated by significantly higher lesion scores 17 days after initial exposure and by loss of two birds in the control strain exposed groups. Low lesion scores and no deaths due to coccidiosis characterized the use of the Wis-F-125 strain. Flock immunity, as determined by immunity challenge, was equivalent between the control strain and the higher dosages of Wis-F-125. The Wis-F-96 strain did not adequately immunize chickens in these experiments.
Animals↗
Anticoccidial activity of narasin in battery raised broiler chickens.
The anticoccidial activity of the ionophorus antibiotic narasin was tested against six species of coccidia (Eimeria acervulina, Eimeria mivati, Eimeria maxima, Eimeria necatrix, Eimeria brunetti, and Eimeria tenella) in battery-raised broilers. Feeding ration medicated with 60, 80, or 100 ppm narasin significantly improved weight gains during the periods of D 0 to D7 and D 0 to D 14 (D 0 = day of inoculation with sporulated oocysts), compared with the weight gains in corresponding inoculated groups fed unmedicated feed. A similar protective effect of the medication was seen with feed conversion ratios (feed consumed/bird weight) and coccidiosis-induced mortality. With most species studied, 40 and 60 ppm narasin was not as efficacious as 80 or 100 ppm. The maximum numerial improvement in weight gain and feed conversion ratio was with 80 ppm narasin. Gross intestinal lesion scores were reduced by medication compared with the scores in birds fed unmedicated feed. The overall trend was for a larger reduction in lesion score with higher drug levels. Narasin at 80 or 100 ppm was generally more effective in controlling individual or mixed species infections of coccidia than 99 ppm monensin.
Animals↗
Effects of anaerobic bacteria on Eimeria tenella infection in bacteria-free, monofloral, and conventional chickens.
Bacteria-free, monofloral, and conventional chicks were infected with Eimeria tenella. Monofloral chicks were established by inoculating birds in several gnotobiotic isolators with a single species of Escherichia coli or with one of three Bacteroides sp. isolates (No. 157, No. 202, or No. 366). Daily weights of individual birds were recorded for six days post-infection (PI). On Day 6 PI all birds were sacrificed and cecal lesions were scored. Conventional, infected birds lost weight on days 5 and 6 PI and showed severe lesions. Birds maintained as monofloral groups with isolates of Bacteroides sp. No. 157, No. 202 or E. coli showed equally severe lesions, but lost weight only on day 6 PI. Conventional, uninfected birds with no lesions, birds infected with Bacteroides sp. isolate No. 366 with mild lesions, and bacteria-free birds with mild to severe coccidial lesions all continued to gain weight on each day post-infection.
Animals↗
Monensin, Eimeria tenella infection, and effects on the bacterial populations in the ceca of gnotobiotic chickens.
Bacteria-free chicks in separate plastic film isolators were inoculated orally with single species of bacteria. Within an isolator, half the birds were fed unmedicated feed and half received feed containing 100 ppm monensin. With clostridium perfringens as the established species of monoflora, bacterial counts from the duodenum were 10(4) times lower and counts from the ceca were three times lower in monensin-fed birds compared to unmedicated birds. Infection with Eimeria tenella stimulated an eight-fold increase in the numbers of C. perfringens in the ceca of unmedicated birds but no increase in monensin-fed birds. With Bacteroides sp. or Streptococcus faecalis as monoflora, there was no difference in the cecal or duodenal populations between medicated and unmedicated birds uninfected with coccidia. In contrast to C. perfringens, populations of Bacteroides sp. and S. faecalis in the ceca decreased five to 100-fold in both medicated and unmedicated chicks after infection with E. tenella. Duodenal populations of C. perfringens, Bacteroides sp., and S. faecalis were unaffected by the coccidial infection.
Animals↗
Effect of the anticoccidial arprinocid on production, sporulation, and infectivity of Eimeria oocysts.
Medication of broilers with arprinocid [MK-302, 9-(2-chloro-6-fluorbenzyl adenine)] had 3 distinct effects on oocysts; (1) the number of oocysts produced was decreased, (2) fewer of the oocysts sporulated, and (3) those oocysts which did sporulate were less infective than those from unmedicated birds. The drug level necessary to prevent passage of oocysts depended on the species and strain of coccidia. To essentially eliminate oocyst production (less than 5% of controls) required medication with the following levels of arprinocid: 70 ppm with Eimeria maxima; 60 ppm with E. mivati, E. E. necatrix, and E. brunetti; and 50 ppm with E. tenella. With E. acervulina, oocysts were completely eliminated by 60 ppm of arprinocid with one field strain but were still numerous at 70 ppm with a second field strain. Oocysts recovered from birds on medication often failed to sporulate. No sporulation was seen at drug levels of 30 ppm or above with E. maxima and E. mivati. The level of arpinocid required to prevent sporulation with other species depended on the strain being studied, but varied from 30 ppm to 70 ppm. The oocysts of E. acervulina, E. mivati, E. tenella, and E. brunetti recovered from medicated birds that subsequently sporulated, were less infective when inoculated into susceptible birds, than oocysts from unmedicated birds. Oocysts from low medication level with E. necatrix (30 ppm) and E. maxima (10 ppm), once sporulated, were as infective as oocysts from unmedicated control birds, even though the numbers produced were less. No differences were detected in the time oocysts were produced between medicated and unmedicated birds infected with E. acervulina, E. maxima, E. brunetti, and E. tenella.
Adenine↗
Prevalence of Eimeria acervulina, Eimeria necatrix, Eimeria brunetti and Eimeria tenella in Georgia (USA) as demonstrated by immunity challenge techniques.
Eimeria acervulina, E. necatrix, E. brunetti and E. tenella were found to be widely distributed in north-east Georgia. 2. Using immunity challenge techniques 17 flocks from 12 to 72 weeks of age showed significantly lower lesion scores for the first three species compared with susceptible control flocks similarly challenged. Only one flock was found to be susceptible to E. tenella. No mortality occurred in the field flocks after challenge while 20 to 60% mortality occurred in the susceptible controls. 3. Partial immunity occurred more frequently in field flocks aged 28 weeks of age or less (62%) than in older flocks (30%). Lesion scores ranged from 0-1 to 2-2 with the former and 0-1 to 0-6 with the latter group. 4. A modification of the immunity challenge method was developed using lesion scores as the major criterion determining immunity. The method permits testing of four species infecting different parts of the digestive tract in one group of birds.
Animals↗
Effects of monensin-feeding regimens on flock immunity to coccidiosis.
Feed medication with monensin caused delays in development of immunity in two floor-pen experiments which simulated commercial broiler production. Development of immunity was retarded with the higher level of monensin (120 p.p.m.) but was progressively less delayed as the monensin level was decreased (100, 60 or 0 p.p.m.). Delay was greatest with Eimeria tenella, but also occured with intestinal species including E. acervulina, E. brunetti, E. maxima, E. mivati, and E. necatrix. Drug withdrawal permitted earlier development of immunity. Plans involving use of monensin on layer replacements which later will be maintained on the floor without medication should consider: 1) prevalence of infective oocyst exposure in the area, 2) the lowest possible level of drug required for protection, and 3) its use for the shortest possible period of time.
Administration, Oral↗
Effect of infectious bursal disease on the severity of Eimeria tenella infections in broiler chicks.
A study was initiated to determine whether prior exposure to infectious bursal disease virus (IBDV) influenced the susceptibility of young broiler chicks to Eimeria tentella infections. When one-day-old chicks infected with IBDV were subsequently challenged with E. tenella at 7 days of age, they suffered significantly higher mortality and lesion scores than their hatchmates which were not exposed to IBDV. Initial exposure to IBDV also had an effect on the development of E. tenella induced hemorrhaging. Hemorrhaging commenced late on the third day following E. tenella inoculation in chicks infected with both IBDV and E. tenella, while bleeding did not occur in the E. tenella alone group until late on the fourth day post-coccidial challenge. No significant differences in weight gains at 7 or 14 days after E. tenella infection were observed between chicks receiving the double infection and those given only E. tenella.
Animals↗
Anticoccidial activity of salinomycin in battery raised broiler chickens.
Infections with single species of Eimeria acervulina, E. mivati, E. maxima, E. tenella, E. necatrix, and E. brunetti, and the six species mixed, were utilized in three separate battery experiments to evaluate the anticoccidial efficacy of various levels of salinomycin (AHR-3096), a fermentation product of a strain of Streptomyces albus. At the 60 to 100 p.p.m. treatment levels, this compound showed significant anticoccidial activity for all parameters studied (mortality, weight gain, feed conversion, dropping scores, and lesion scores). The mortality due to coccidiosis was reduced to 0.1% in the medicated infected birds. Some activity, as measured by weight gain, was seen in the lower levels of salinomycin medication (12.5 to 50 p.p.m.), but other parameters, including mortality and lesion scores, indicated less activity than that seen with the higher treatment levels. At 100 p.p.m., there was no apparent effect on the compound on bird performance in uninfected control birds. Salinomycin at the 100 p.p.m. treatment level was statistically as effective as 121 p.p.m. monensin (reference anticoccidial) in controlling coccidiosis.
Animal Feed↗
Anticoccidial activity of salinomycin in floor-pen experiments with broilers.
The anticoccidial agent salinomycin (AHR-3096) was compared at various treatment levels (60 to 100 p.p.m.) in two experiments against unmedicated and either 100 or 121 p.p.m. monensin-medicated groups to evaluate its performance under floor-pen conditions. Various methods for the initial rearing of birds and coccidial exposure were employed to test the efficacy of salinomycin against severe, moderate, and mild coccidiosis. Salinomycin at all treatment levels showed definite anticoccidial activity resulting in improved weights, feed conversion ratios, lesion scores, and mortality compared with unmedicated controls. In pens with severe coccidiosis, this compound demonstrated a significant improvement in all parameters when compared with the corresponding unmedicated controls. Salinomycin-treated pens exposed to light coccidiosis usually had a numerical increase in the parameters over the unmedicated control groups. Statistical analysis of overall main effects on mortality, weight gain, and feed conversion ratio showed no significant differences between the activity of any level of salinomycin and monensin.
Animal Feed↗
Methyldopa-induced granulomatous hepatitis.
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Biopsy, Needle↗
Effects of high environmental temperatures on cecal coccidiosis.
Maintenance of broiler or White Leghorn cockerels in a high temperature (32 C.), high humidity (90%) environment for six days following artificial infection with Eimeria tenella significantly reduced coccidiosis severity as compared to birds similarly infected and maintained in an ambient environment averaging 24.5 C., and 62% humidity. Disease severity was determined by lesion scores, fecal scores, and hematocrit readings. The heavier broiler stock maintained body temperatures of 0.7-1.6 C. higher than those birds kept at ambient temperatures for the entire six days. Body temperatures of heat-treated Leghorn cockerels were 0.9 C. higher during the first 48 hours post-inoculation (P.I.), but similar to ambient temperature controls for the last four days. Elevated body temperatures during the first two days following inoculation impaired the survival and development of some parasites while shorter periods (24 hours) of heat treatment did not affect parasite survival.
Animals↗
Coccidiosis: effects of high environmental temperatures on anticoccidial protection.
In a series of nine experiments birds subjected to heat-stress showed decreases of 9 to 61 percent in feed intake. In only one of these experiments, involving E. acervulina and monensin, was there sufficient reduction of anticoccidial intake to partially nullify effects of drug protection. In this case, a 40 percent decrease in monensin intake resulted in significantly higher lesion scores (1.9 vs. 1.0) (P less than or equal to 0.05) in birds maintained at 32 C. for days 1 to 7 postinfection (P.I.) compared to controls maintained at 20C. No other failures due to heat stress occurred with this anticoccidial in three other trials with E. acervulina or or five trials involving E. tenella infection. In one experiment E. tenella coccidiosis (lesion scores 0.7 vs. 1.1) was more severe in the cool environment than in birds under heat-stress from 2 to 7 days P.I. Similarly, less severe lesions of E tenella (0.4 vs. 0.8) occurred during heat-stress (32 C) than in controls maintained at 11 C. in zoalene-fed and unmedicated control birds. No differences in lesion scores occurred in birds in hot versus cool room environments in two experiments involving sulfaquinoxaline or one with robenidene and E. tenella infection. E tenella lesions inunmedicated controls were significantly more severe in the cool than the hot environment in one experiment. Results from these experiments suggest that decreases in feed and anticoccidial intake during heat-stress could seldom be the cause of coccidiosis breaks under field conditions.
Animals↗
Efficacy of different feeding levels of monensin in the control of coccidiosis in broilers.
The feed level of monensin which gave maximal protection from coccidial infection in broilers reared in floor pens depended on the severity of the coccidial exposure and the criteria of infection studied. With indirect seeding of pens with coccidia (light coccidial exposure), 40 ppm was as efficacious as 100 ppm in improving weight gain, lesion score, and feed conversion. Statistical analysis with direct seeding (seeder birds; severe coccidial exposure) showed that feed levels of 84 and 102 ppm gave maximal improvement of weight gain and 4-week feed conversion, respectively. Further increasing the monensin level from 100 to 121 ppm did not improve weight gain and feed conversion at 8 weeks. Conversely, the relationship of plasma pigmentation and total lesion scores to monensin feed levels indicated that increasing the dosage of monensin from 100 to 121 ppm improved the performance of the broilers on the basis of these 2 infection indicators.
Administration, Oral↗
Detection and determination of sulfuric acid aerosol - difficulties in trapping.
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Aerosols↗
Progress in the control of coccidiosis with anticoccidials and planned immunization.
New anticoccidials continue to be introduced to the poultry industry on an average of about one every 2 years. Revised requirements have increased costs of discovery, development, and approval by the Food and Drug Administration to several million dollars for each product. Gross sales of anticoccidials are now estimated to be in excess of $30,000,000 annually. Anticoccidials are almost universally used in starter rations for meat-type birds being raised under floor-pen management. Protection is more important with these fast-growing birds than with egg-producing types where immunity and cage layer management modify demands for anticoccidials. Coccidiosis mortality has generally been eliminated by all 25 approved anticoccidials if properly used. Selection of specific anticoccidials is based on the ability of the anticoccidial to: (1) improve weights and (2) feed conversion, and (3) to suppress development of lesions. Costs of the product may influence decisions on which one to use. With some anticoccidials the rapid emergence of drug resistant strains has been the biggest problem. "Switching" among the 13 classes of anticoccidials and the so-called "shuttle program" are common methods used to avoid development of resistance. Preventive medication will probably continue to constitute the major method of coccidiosis control with meat-type poultry if attempts to develop economic cage-type management do not supplant current litter and floor-pen management. Immunity acquired through incidental or planned immunization is more important in control of coccidiosis with layer and breeder flocks raised in floor-pens. Some progress in development of avirulent immunogenic strains of different species of coccidia has been reported and further research efforts in this direction should be encouraged.
Administration, Oral↗
Anticoccidial activity of Lasalocid in control of moderate and severe coccidiosis.
The fermentation product lasalocid ("Antibiotic X-537A," Hoffmann-LaRoche) showed good anticoccidial activity when administered via feed at 50 or 75 ppm in a replicated floor-pen experiment. Lasalocid was compared with monensin (121 ppm) ("positive control") and also with unmedicated ("negative") controls in pens heavily seeded or indirectly seeded with eight species of coccidia (Eimeria acervulina, E. brunetti, E. hagani, E. maxima, E. mitati, E. necatrix, E. praecox, and E. tenella). Under severe coccidiosis exposure (litter seeded by infected birds) both anticoccidials permitted significantly increased weights, improved feed conversions, and reduced lesion scores. Shank depigmentation was numerically less in anticoccidial-treated birds than in unmedicated controls, though not significantly. Coccidiosis mortality (lesions or parasites demonstrated) was 10% in unmedicated controls. Lasaloic reduced this mortality significantly to 0.8% at 50 ppm and 0.4% at 75 ppm. No coccidiosis mortality occurred with monensin-fed birds. With moderate exposure (indirect seeding) both anticoccidials permitted significantly greater weight gains and less shank depigmentation than in unmedicated controls. In unmedicated pens severity of coccidiosis was significantly greater in the intentionally seeded pens than in indirectly seeded pens with all parameters except depigmentation. This design provided a practical procedure for testing anticoccidials in a single experiment against severe and moderate exposures to coccidiosis as are normal in broiler production.
Administration, Oral↗