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Biomedical subjects

M D Ruff

Publications and source records attributed to M D Ruff.

98 records · Page 6Linked to original sources

Efficacy of arprinocid against coccidiosis of broilers in battery and floor-pen trials.

Medication of broilers with arprinocid [9-(2-chloro-6-fluorophenylmethyl)-9H-purine-6-amine] gave protection against the effects of coccidiosis in both battery and floor-pen trials. In battery trials, efficacy was tested on single-species inoculations of Eimeria acervulina, E. mivati, E. necatrix, E. maxima, E. Brunetti, and E. tenella. Two strains of each species recently recovered from the field, were tested separately. In floor-pen trials, all six species, both field and laboratory strains, were used as a mixed infection. In batteries, 60 and 70 ppm essentially eliminated coccidiosis-induced mortality and weight depression. Effects of 50 ppm on weight gain were variable. The effectiveness of different medication levels varied between strains within a species. In floor-pen trials, 40, 60, or 80 ppm was effective in controlling mortality and weight depression, and increasing feel-conversion ratios. All levels were significantly as effective as monensin in protecting against coccidiosis. With severe exposure to coccidia, 60 and 80 ppm gave significantly lower lesion socres than did 40 ppm of arprinocid or 120 ppm monensin.

Adenine↗

Changes in carotenoid and vitamin A levels in young turkeys infected with Eimeria meleagrimitis or E. adenoeides.

Changes in levels of plasma xanthophyll, plasma retinol, liver retinol, and liver retinylpalmitate in poults infected with Eimeria meleagrimitis or E. adenoeides were measured by high-performance liquid chromatography. Infection with either species significantly reduced total plasma carotenoids; the reduction was due largely to a decrease in xanthophyll to approximately 50% of control levels on the day of maximum effect. In addition, E. meleagrimitis infection decreased plasma retinol levels from 1.84 microgram/ml plasma (controls) to 1.00 microgram/ml plasma on day 6 postinoculation. Concomitantly, liver retinol levels fell from 0.23 microgram/mg protein (controls) to 0.15 microgram/mg protein, and liver retinylpalmitate levels fell from 0.74 microgram/mg protein (controls) to 0.44 microgram/mg protein. In contrast, Eimeria adenoeides infection caused little change in either plasma or liver retinol levels.

Animals↗

Influence of dietary aflatoxin on the severity of Eimeria acervulina infection in broiler chickens.

Broiler chicks (Hubbard x Hubbard) receiving 2.5 microgram of aflatoxin/g of diet and inoculated with sporulated oocysts of Eimeria acervulina gained significantly less weight than chicks receiving either aflatoxin or coccidia alone. Aflatoxin alone affected body weight more in females than males. Blood parameters, however, showed no sex-related differences to E. acervulina or aflatoxin. E. acervulina had no effect on packed cell volume, red cell number, or hemoglobin levels. Gross lesions in the intestine caused by the coccidia appeared the same with or without dietary aflatoxin. Either aflatoxin or E. acervulina alone reduced the plasma pigment. When both were present, depigmentation was greater with some strains of coccidia than with either alone. Aflatoxin alone reduced the plasma levels of cholesterol and protein. The effect of E. acervulina on cholesterol or protein, with or without aflatoxin, depended on the coccidial strain used.

Aflatoxins↗

Nutrient absorption and changes in blood plasma of stunted broilers.

Broilers were collected from three farms in which there was high mortality, stunting, and leg weakness characteristic of a condition referred to by various names, including infectious stunting, pale bird syndrome, malabsorption syndrome, and helicopter disease. Broilers were also collected from a fourth farm in which no birds showed the syndrome. Most but not all of the stunted broilers exhibited paleness, poor feather development, and broken feather shafts. Most lesions and abnormalities of the internal organs were of low frequency and not correlated with stunting. Bleaching of the pancreas, however, was found in 47% of the stunted broilers. Compared with normal-sized broilers from the same farms, the stunted broilers had increased plasma protein, decreased plasma pigment, and a sometimes increased liver glycogen level. The increase in protein was the result of increased levels of alpha, beta 1, gamma 1 and gamma 2 globulins. The levels of plasma glucose, body temperature, breast muscle moisture, packed cell volume, and intestinal pH were not affected in stunted broilers. Likewise, no difference could be demonstrated between stunted and normal broilers in the in vitro intestinal absorption of glucose or L-methionine.

Animals↗

Effect of aging on survival and pathogenicity of Eimeria acervulina and Eimeria acervulina and Eimeria tenella.

After 6 to 8 months of storage, cultures of sporulated Eimeria acervulina and E. tenella oocysts ahd a marked drop in the number of sporocysts that survived grinding, sporozoites that survived after excystation, and sporozoites that penetrated chick kidney cells in vitro. The rate of excystation was unaffected by storage of up to one year. In vivo pathogenicity, based on weight gain, lesion score, and plasma pigment, declined after 5 months of oocyst storage. The reduction in pathogenicity in vivo could be compensated for by adjusting the inoculation dosage to reflect the loss of infectivity seen in the in vitro test.

Animals↗

Effect of amprolium on production, sporulation, and infectivity of Eimeria oocysts.

Amprolium reduced the number of oocysts shed by Eimeria acervulina, E. maxima, E. necatrix, and a mixture of susceptible strains of E. tenella. Sporulation of oocysts from mediated chickens was reduced compared with that of oocysts from unmedicated chickens. Sporulation was reduced by levels of 0.0250% amprolium for E. acervulina and by levels of 0.0060% for E. maxima and the susceptible E. tenella. Not enough oocysts were recovered to measure sporulation of E. necatrix. Sporulation reduction was not affected by the method of administration of amprolium (feed or water), except with E. acervulina, for which fewer oocysts sporulated when 0.0120% amprolium was added in the drinking water than when 0.0125% amprolium was added to the feed. Conversely, amprolium medication had no effect on the sporulation of an amprolium-resistant E. tenella. When fed to unmedicated chickens, those oocysts from amprolium-medicated chickens that did sporulate were as infective as oocysts recovered from unmedicated chickens.

Amprolium↗

In vivo role of tumor necrosis-like factor in Eimeria tenella infection.

The effect of tumor necrosis-like factor (TNLF) on the pathogenesis of coccidiosis was investigated. Injection of crude chicken TNLF enhanced the weight loss caused by Eimeria tenella infection. Rabbit polyclonal antibody against recombinant human tumor necrosis factor-alpha (rhTNF) partially restored E. tenella-induced weight loss in SC chickens, but not in TK chickens. However, injection of chickens with chicken TNLF, rhTNF, and rabbit serum against rhTNF had no significant effect on cecal lesions. Both SC and TK chickens produced circulating TNLF following primary, but not secondary infection, and SC chickens showed higher level of TNLF production than TK chickens. Peripheral blood leukocyte-derived macrophages from SC and TK chickens produced a significant amount of TNLF compared to the preinfection condition when cocultured with sporozoites. In general, macrophages from SC chickens produced higher levels of TNLF than those from TK chickens. No significant difference was observed between primary and secondary infection. These results suggest that the excessive TNF production may be involved in weight loss caused by E. tenella infection in SC chickens.

Animals↗