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Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 235 records · Page 13Linked to original sources
PubMed1982

Roxarsone toxicity in the chick as influenced by dietary cysteine and copper and by experimental infection with Eimeria acervulina.

A series of experiments was conducted with crossbred chicks to determine the effects of L-cysteine, copper, and coccidiosis on roxarsone toxicity. Levels of roxarsone in excess of 50 mg/kg depressed performance and increased kidney arsenic concentration. L-cysteine x HCl x H2O (59%) increased rate and efficiency of gain when added to the basal diet, but depressed performance, increased kidney arsenic concentration, and enhanced mortality when added to diets containing toxic levels of roxarsone (200 mg/kg or higher). Moreover, excess copper (500 mg/kg) partially alleviated the gain/feed depression due to the combination of cysteine and roxarsone. Cysteine, in fact, increased feed efficiency in birds fed excess copper in the absence of roxarsone. Eimeria acervulina infection (duodenal coccidiosis) depressed gain and feed efficiency. The depression in feed efficiency was more severe in the presence of roxarsone (50 or 300 mg/kg). In the absence of coccidiosis, 50 mg/kg roxarsone slightly increased gain/feed ratio.

Animals↗
PubMed1982

Effect of dietary protein level and monensin on performance of chicks.

Four experiments were conducted to investigate a possible interaction between dietary protein level and monensin on growth performance of young chicks. Crossbred chicks (New Hampshire X Columbian) or commercial broiler chicks (Hubbard X Hubbard) were fed corn-soybean meal diets containing various protein levels with or without added monensin (160 or 121 mg/kg). Monensin had little or no effect on growth performance of crossbred chicks fed diets containing 24 or 20% protein. However, growth performance of chicks fed 16% protein diets was depressed 15 and 8% by 160 and 121 mg/kg monensin, respectively. With commercial broiler chicks a marked interaction was observed between dietary protein level and monensin. As dietary protein level decreased, the depression in performance from monensin increased. At 24.0, 21.5, 19.0, and 16.5% protein, weight gains at 4 weeks of age were depressed 20, 29, 35, and 45% by 160 mg/kg monensin and 7, 14, 19, and 28% by 121 mg/kg monensin, respectively. Linear regression analysis indicated that 121 mg/kg monensin depressed growth rate an additional 2.7% for each 1% reduction in dietary protein level. A large portion of the growth depression from monensin could be explained by reduced feed intake. The results of this study indicate that level of dietary protein has a profound effect on the magnitude of growth depression caused by addition of monensin to chick diets. Thus, deficient levels of dietary protein should be avoided when using this anticoccidial drug in broiler feeds.

Animal Feed↗
PubMed1982

Amino acid utilization as influenced by antibacterial and anticoccidial drugs.

Utilization of amino acids, sulfur-containing amino acid (SAA) in particular, is little affected by antibiotic and anticoccidial compounds. Coccidiosis (i.e., Eimeria acervulina infection) likewise seems to have little effect on SAA utilization. Copper sulfate, a commonly used antibacterial-antifungal compound (used at levels of 100-250 mg/kg diet), interacts with SAA. Hence, at upper levels of copper ingestion (i.e., 250 mg/kg and higher), copper binds SH compounds such as cysteine and reduced glutathione. Dietary SAA requirements are increased in both chicks and rats by dietary copper levels of 250 or 500 mg/kg. Hepatic copper deposition is enhanced by copper feeding and also by E. acervulina infection. These two effects, moreover, appear to be additive. The organic arsenic compound, roxarsone, interacts with SAA also, but in a different way. Thus, whereas added dietary cysteine partially ameliorates copper toxicity due to the binding of copper by cysteine-SH with subsequent excretion, roxarsone toxicity (i.e., 500 mg/kg diet) is exacerbated by supplemental cysteine.

Amino Acids↗
PubMed1981

Interaction between dietary protein/amino acid level and parasitic infection: morbidity in amino acid deficient or adequate chicks inoculated with Eimeria acervulina.

In a series of experiments designed to assess the chick's sulfur amino acid (SAA) requirement during acute coccidiosis, a striking and unexpected infection X SAA interaction was discovered. When chicks were fed diets severely deficient in SAA, Eimeria acervulina infection produced a marked growth response, while birds consuming SAA-adequate diets exhibited the expected severe growth depression when given the same dose of E. acervulina oocysts. Although the interaction was originally demonstrated in birds fed crystalline amino acid diets, it was subsequently demonstrated with intact protein diets as well. The interaction was also shown not to be unique to the SAA. Thus, lysine and E. acervulina interacted in the same manner. In fact, when birds were fed diets severely deficient in lysine, E. acervulina infection brought about a doubling of both rate and efficiency of weight gain. It was also established that the growth response to infection resulted from E. acervulina per se and not from any other component of the infective inoculum.

Amino Acids, Sulfur↗
PubMed1981

Utilization of the D-isomers of arginine and histidine by chicks and rats.

Young chicks and rats were fed crystalline amino acid diets deficient in either arginine or histidine, and the growth-promoting capacity of the D-isomers of these two amino acids was examined. D-arginine had no growth-promoting activity in either chicks or rats. D-histidine had minimal growth-promoting activity (about 20%) in chicks and no bio-activity in rats.

Animal Feed↗
PubMed1981

Kidney arginase activity in chicks fed diets containing deficient or excessive concentrations of lysine, arginine, histidine, or total nitrogen.

Three experiments were conducted with 1 to 2-week-old chicks fed purified crystalline amino acid diets. Kidney arginase activity increased substantially when total dietary nitrogen exceeded the dietary requirement for maximal chick weight gain. Single deficiencies of either histidine or lysine in nitrogen-adequate diets also resulted in marked increases in enzyme level. Arginine deficiency resulted in a slight increase in arginase activity, but the magnitude of the increase appeared to have little effect on efficiency of arginine utilization. Further, the response could be prevented by making lysine and arginine equally limiting. Increasing the lysine:arginine ratio to two in a nitrogen-deficient diet did not increase arginase activity. The same ratio in a arginine- and nitrogen-adequate diet resulted in a twofold increase in arginase activity accompanied by reductions in rate and efficiency of weight gain.

Amino Acids, Essential↗
PubMed1981

The effect of methionine or cysteine on cobalt toxicity in the chick.

Three experiments were conducted to investigate the interaction of cobalt with sulfur-containing amino acids in the chick. Fortified corn-soybean meal diets were fed and tissue concentrations of cobalt were assessed. In Experiment 1, three levels of cobalt (0, 250, and 500 microgram/g) were fed in the presence and absence of .50% supplemental DL-methionine. Dietary additions of cobalt depressed growth rate and caused cobalt accumulation in the liver and kidney. Supplemental methionine in excess of the requirement for maximal chick weight gains partially alleviated the depression in performance and decreased cobalt accumulation in the liver and kidney. Two levels of cobalt (0 and 500 microgram/g) were fed in the presence and absence of .59% supplemental L-cysteine.HCl.H2O (isosulfurous to .50% DL-methionine) in Experiment 2. Again, cobalt depressed performance and accumulated in the liver and kidney. The surfeit of cysteine increased weight gain and decreased cobalt accumulation in the liver but not in the kidney. In Experiment 3, two levels of cobalt (0 and 250 microgram/g) were fed in the presence and absence of two levels of excess DL-methionine (.50 and 1.0%) or two levels of excess cysteine.HCl.H2O (.59 and 1.18%). Multiple linear regression analysis of gain on sulfur consumed from methionine or cysteine indicated that cysteine was almost 6 times more efficacious than methionine in alleviating cobalt toxicity. In fact, cysteine supplemented at a level of 1.18% completely alleviated the growth depression caused by 250 microgram/g cobalt. Both methionine and cysteine reduced cobalt accumulation in the liver and kidney, but the liver was affected to a greater extent than the kidney.

Animals↗
PubMed1981

Eimeria acervulina infection in the chicken: a model system for estimating nutrient requirements during coccidiosis.

Eimeria maxima inoculations of 5 X 10(4) oocysts and E. acervulina inoculations of 2 X 10(5) to 4 X 10(5) oocysts were shown to depress growth by 15 to 20% in young chicks fed crystalline amino acid (CAA) diets. The intestinal lesions produced were typical of light to moderate coccidiosis. In one experiment, the performance of chicks fed monensin was increased in the presence, but not in the absence, of E. acervulina. Thus, monensin prevented the negative effects of E. acervulina on chick performance. This coccidiosis X monensin interaction was also indicative of an active coccidiosis infection. Severe E. acervulina infections were produced by inoculations of 1 X 10(6) or 2 X 10(6) oocysts. Under these conditions, gain was depressed by 30 to 40% and the intestinal lesions produced were indicative of severe coccidiosis. Also, E. acervulina infections were more severe in birds fed CAA diets than in birds fed corn-soybean meal diets. Trypsin incubation of the oocysts prior to inoculation had no significant effect on performance regardless of diet type. Based upon growth rate, intestinal lesions, and responses to anticoccidial drugs, it was clearly demonstrated that coccidiosis of varying severity cn be produced in birds fed CAA diets. In addition, it was observed that the CAA diet, with 24.58% amino acids, contained adequate levels of all indispensable nutrients, even during coccidiosis. This assures that the diet can be used effectively for nutrient requirement studies during coccidiosis.

Amino Acids↗
PubMed1981

Eimeria acervulina infection in the chicken: sulfur amino acid requirement of the chick during acute coccidiosis.

Five assays were conducted to determine whether Eimeria acervulina infection would alter the chick's sulfur amino acid (SAA) requirement. Chicks were housed in heated starter batteries with raised wire floors and fed completely purified crystalline amino acid diets. With light to moderate E. acervulina infection, data were somewhat inconclusive. In Assay 1, infected birds responded to levels of SAA above those required by healthy birds; but in two subsequent assays no difference in SAA requirements due to infection could be detected. Therefore, two additional assays were conducted in birds inoculated with a heavy dose of E. acervulina oocysts. In neither of these assays did E. acervulina infection show any indication of altering SAA utilization. When data from the five studies are viewed together, it is clear that E. acervulina infection did not increase the chick's SAA requirement.

Amino Acids, Sulfur↗
PubMed1981

Performance of healthy and Eimeria acervulina-infected chicks as influenced by anticoccidial drugs and source of dietary protein.

Four experiments were conducted to evaluate an alleged interaction between the anticoccidial drugs, monensin and lasalocid, and dietary protein source. Chicks were fed practical diets (approximately 24% crude protein) containing from 0 to 13% animal-source protein supplied by either a fish meal-meat and bone meal combination or by feather meal. Monensin (121 mg/kg) and lasalocid (125 mg/kg) were evaluated for anorexigenic activity in health birds and for growth-enhancement activity in E. acervulina-infected birds. Diet-by-coccidiostat interactions were not detected in any of these experiments. The addition of monensin or lasalocid depressed performance significantly in only one of the experiments, but the magnitude of depression was similar regardless of level of animal-source protein. Efficacy of the coccidiostats, as judged by performance of chicks infected with E. acervulina, was not altered by diet type.

Animals↗
PubMed1980

Acute lymphocytic leukemia masquerading as acute osteomyelitis. A report of two cases.

Two children each developed a focal destructive bone lesion accompanied by intermittent fever, swelling, tenderness and elevated ESR. Blood counts were normal; bone marrow aspiration showed acute leukemia. The bone lesions healed in both patients after anti-leukemic therapy. We suggest that the similar roentgenographic appearance of osteomyelitis, bone infarction and focal destructive lesions in leukemia probably reflects a common, basically ischemic process of bone.

Acute Disease↗
PubMed1980

Studies on the utilization of lysinoalanine and lanthionine.

Studies were conducted to determine the nutritional value of lysinoalanine for rats and chicks and the nutritional value of lanthionine for chicks. For each experiment, purified crystalline amino acid diets and crystalline lysinoalanine and lanthionine were employed. Results indicated that the lysine moiety of lysinoalanine is completely unavailable to the rat and only partially available to the chick. Of 10 rats fed lysinoalanine, seven developed nephrocytomegaly. The lanthionine studies indicated that the cysteine moiety of lanthionine is 32% available when fed as the racemic mixture and 52% available when fed as the L-DL-isomeric mixture. Thus, it appears that lysinoalanine formation in alkali-treated proteins results in a corresponding decrease in nutritionally available lysine. However, the lanthionine formed under similar conditions results in loss of only one-half of the corresponding level of nutritionally available cysteine.

Alanine↗
PubMed1980

Utilization of the D- and L-isomers of methionine and methionine hydroxy analogue as determined by chick bioassay.

Young chicks were fed sulfur-amino acid (SAA) deficient soy protein or crystalline amino acid diets to evaluate the relative efficacy of the D- and L-isomers of methionine and 2-hydroxy-4-(methylthiobutyrate)Ca (OH-methionine). With crystalline amino acid diets, D-OH-methionine ([alpha] D25 = +24.3) was decisively superior to L-OH-methionine ([alpha] D25 = -25.3) as a source of methionine activity. The D-isomer of OH-methionine was also much more toxic than the L-isomer as measured by magnitude of growth depression and severity of hemolytic anemia. DL-OH-methionine was intermediate in toxicity between the pure D- and L-isomers, but its efficacy for growth promotion was greater than what would have been predicted from its (equal) content of the two isomers. With methionine, the L-isomer was superior in growth-promoting efficacy to the D-isomer; DL-methionine, however, more nearly paralleled the response to L- than to D-methionine. In all cases where the crystalline amino acid diet was fed, regardless of isomeric form, methionine was vastly superior to OH-methionine as a source of SAA activity. With the soy-protein diet, on the other hand, differences in efficacy between methionine and OH-methionine were minimal, and isomeric form was of lesser consequence.

Amino Acids, Sulfur↗