Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 181 records · Page 10Linked to original sources

PubMed1987

Amelioration of ethionine toxicity in the chick.

Several chick bioassays were conducted to evaluate means of ameliorating ethionine toxicity. Supplementing a corn-soy diet marginally deficient in sulfur amino acids (methionine + cystine) with .075% D,L-ethionine reduced weight gain in 8-day-old chicks by 70% compared to gains of unsupplemented controls. Dietary addition of .50% DL-methionine prevented reduction in weight gain and feed intake resulting from ethionine supplementation whereas feeding supplemental L-cystine was without effect. Supplementation of the ethionine-containing diet with either choline or betaine ameliorated the growth depression, although neither compound was able to completely overcome the toxic effects of ethionine. Dietary ethionine did not affect plasma levels of free methionine or cystine but did increase plasma free glycine 6-fold. Dietary addition of .50% DL-methionine caused normalization of plasma glycine levels whereas it elevated plasma methionine concentration. Although results suggested the possibility of ethionine-induced serine or threonine deficiency, dietary additions of .75% L-serine or .75% L-threonine failed to improve chick weight gain. These studies suggest that ethionine, in addition to affecting transsulfuration and transmethylation activity may exert specific effects on certain amino acids in tissue pools.

Amino Acids↗

PubMed1987

Efficacy of a manganese-protein chelate compared with that of manganese sulfate for chicks.

Based on bone manganese (Mn) accumulation during a 14-day feeding period. Mn bioavailability in a Mn-proteinate product was judged to be not significantly different than that provided by MnSO4.H2O. Bone and bile Mn concentrations were reduced markedly when 10% wheat bran was added to a phytate and fiber-free casein-dextrose diet that contained 1,000 mg/kg supplemental Mn from either MnSO4.H2O or the Mn-proteinate.

Animals↗

PubMed1987

Lysine and sulfur amino acid utilization in Eimeria acervulina-infected chicks as affected by narasin.

The effects of supplemental narasin (80 mg/kg) on several dietary factors were investigated in chicks infected with Eimeria acervulina. In Trial 1, chicks were fed a lysine-deficient corn-corn gluten meal diet containing graded increments of crystalline L-lysine.HCl with or without narasin. Supplemental narasin increased weight gain and feed efficiency at all lysine levels fed. Based upon slope-ratio methodology, efficiency of L-lysine utilization was virtually the same in both narasin-fed and control chicks. Trials 2 and 3 evaluated the effect of narasin on methionine utilization in crossbred chicks fed a methionine-deficient soy-feather meal diet supplemented with graded levels of DL-methionine. Narasin supplementation increased weight gain, feed efficiency, and utilization of supplemental methionine in chicks infected with E. acervulina (Trial 2), but had no effect on any of the performance parameters in uninfected chicks (Trial 3). The effects of dietary protein level and source and dietary electrolyte balance on the narasin response of commercial broiler chicks infected with E. acervulina were studied in Trials 4 and 5, respectively. In Trial 4, narasin supplementation increased performance in all cases, and protein source or level had no effect on the narasin response. In Trial 5, rate and efficiency of gain were improved as the electrolyte balance (meq Na + K-Cl/kg diet) increased from 100 to 250, with no further improvement being observed from 250 to 350 meq. Supplemental narasin improved performance and no interaction between electrolyte balance and narasin was observed.

Animals↗

PubMed1987

Interactive effects of monensin, roxarsone, and copper in young chickens infected with Eimeria tenella or a combination of E: tenella and E. acervulina.

Experiments were conducted with crossbred male chicks to evaluate the interactions among roxarsone (50 mg/kg), monensin (121 mg/kg), and copper sulfate (100 mg/kg) as treatments for experimental Eimeria tenella and E. acervulina infections. When diets containing monensin, roxarsone, or a combination of both were offered to chicks for 15 min or 1, 3, 5, or 8 days prior to E. tenella challenge (5 X 10(4) sporulated oocysts), monensin fed for 15 min or roxarsone fed for 1 day prior to challenge prevented morbidity. A mixed infection of E. tenella and E. acervulina (5 X 10(4) and 4 X 10(5) sporulated oocysts, respectively) reduced gain and gain:feed conversion ratios and caused severe duodenal and cecal lesions at Day 6 of the experiment. Infected chicks gained faster when diets were supplemented with either monensin or roxarsone, but monensin produced a larger response than roxarsone. The mixed infection decreased shank pigmentation, with amelioration activity evident from monensin but not from roxarsone. Lesion scores at Day 6 indicated markedly reduced lesions in the duodenum due to monensin but not due to roxarsone; likewise, reductions in cecal lesions occurred in birds fed roxarsone but less so in birds fed monensin. Lesion scores showed little evidence of additivity due to monensin and roxarsone. In general, copper sulfate exerted no independent or interactive effect on any of the parameters evaluated. In a subsequent experiment, the effect of feeding roxarsone in combination with the biological reducing agent, cysteine, was evaluated in E. tenella-infected chicks. Rate and efficiency of gain were improved and lesion scores were reduced by supplementary roxarsone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Extraperitoneal approach for aortoiliac reconstruction of the abdominal aorta.

The extraperitoneal approach is not usually used for reconstruction of the abdominal aorta; however, herein we have made an attempt to influence vascular surgeons to modify this practice. The results in 200 patients approached extraperitoneally have been compared with those of 70 patients explored by the traditional transperitoneal route. The expeditious technique of extraperitoneal exploration described results in significantly less postoperative morbidity due to the pulmonary complications of atelectasis and pneumonia. Intestinal ileus is uniformly brief, and rarely requires nasogastric suction. Patients explored extraperitoneally have demonstrably less pain and were discharged from the hospital sooner. Furthermore, prosthetic graft patency and mortality were comparable in both groups. Thus, the retroperitoneal approach should be the preferred method of aortoiliac reconstruction since the postoperative convalescence period is smoother and shorter.

Aged↗

PubMed1986

Problems and pitfalls in animal experiments designed to establish dietary requirements for essential nutrients.

Problems are encountered in nutrition research designed to establish nutrient requirements. A nutrient requirement must be defined in terms of a specific criterion of response for animals of a given age, weight, sex and body composition. The experimental diet employed must be carefully defined in terms of protein source and level, energy source and level and a multitude of biological availability factors, both negative (e.g., phytate and fiber) and positive (e.g., anabolic bioactivity). Also precursor materials may contribute nutrient bioactivity to the diet. Having considered these factors, the data obtained must be subjected to appropriate statistical methods that will allow objective rather than subjective estimation of the maxima or minima being sought (i.e., the "requirement").

Amino Acids↗

PubMed1986

Efficiency of manganese absorption in chicks fed corn-soy and casein diets.

Experiments were conducted with young chicks to quantify the absorption efficiency of manganese (Mn) using tibia Mn uptake as the response criterion. Chicks in experiment 1 were fed a corn-soybean meal diet and either injected intraperitoneally or crop intubated twice daily with three levels of inorganic Mn provided as MnSO4 X H2O. After 14 d, chicks were killed, and intact tibias were removed to facilitate calculation of bone Mn concentration. Excellent straight-line fits (bone Mn concentration as a function of Mn administered) allowed estimation of gut absorption efficiency of Mn by slope-ratio methodology. Absorption efficiency of Mn was calculated to be 1.71% for chicks fed the corn-soy diet. Identical methodology was employed in experiment 2 wherein chicks were fed a phytate- and fiber-free casein-dextrose diet. An absorption efficiency of 2.40% was estimated for chicks fed this diet. Hence, absorption efficiency of inorganic Mn was 40% greater in chicks fed the purified diet than in those fed the conventional corn-soy diet.

Animal Feed↗

PubMed1986

"Missing" femoral condyle: an unusual sequela to neonatal osteomyelitis and septic arthritis.

Growth deformities of the distal femur and unusual gait disturbances were observed in four girls who had had neonatal osteomyelitis and septic arthritis. In each case apparent absence or hypoplasia of one of the femoral condyles, as seen on plain radiographs, was associated with marked genu varum or genu valgum. Arthrography showed the apparently missing condyle to be present in a cartilaginous form, with preservation of the articular surfaces. Based on these findings, surgical treatment was limited to corrective osteotomy.

Arthritis, Infectious↗

PubMed1986

Toxic effects of supplemental copper and roxarsone when fed alone or in combination to young pigs.

Three experiments were conducted to investigate the roxarsone (3-nitro-4-hydroxyphenylarsonic acid) X copper (Cu) interaction in weanling pigs. Supplemental roxarsone at 400 mg/kg diet decreased rate and efficiency of weight gain and caused visible neurological signs of toxicosis. Copper addition (CuSO4 X 5H2O) at a level of 650 mg Cu/kg diet likewise decreased weight gain and feed efficiency, and it also increased hepatic Cu deposition. The combination of these growth-depressing dosages of roxarsone and Cu resulted in a far greater reduction in gain and efficiency of feed utilization than was the case when either compound was fed alone. A growth-promoting dosage of Cu (250 mg/kg) increased weight gain by 32% in one experiment but showed no efficacy in alleviating the growth-depression resulting from feeding 400 mg/kg roxarsone. A roxarsone dosage of 100 mg/kg increased gain and feed efficiency. Surprisingly, the decreased weight gain in pigs fed 650 mg/kg Cu was ameliorated by feeding 100 mg/kg roxarsone concomitantly. This level of roxarsone also reduced liver Cu concentration substantially. It thus appears that the nature of the roxarsone X Cu interaction is dependent on the dose of each compound administered. Moreover, low-dose roxarsone administration appears to ameliorate Cu toxicity, but low-dose Cu feeding does not show efficacy against roxarsone toxicity.

Animals↗

PubMed1986

Manganese utilization in the chick: effects of corn, soybean meal, fish meal, wheat bran, and rice bran on tissue uptake of manganese.

Experiments were conducted with young chicks to investigate the effect of various feed ingredients on manganese (Mn) bioavailability. Crossbred chicks were fed a Mn-deficient casein-dextrose diet supplemented with corn, soybean meal (SBM), fish meal (FM), wheat bran (WB), or rice bran (RB). Although these feed ingredients contain significant quantities of Mn, dietary addition of all five ingredients consistently depressed Mn deposition in key tissues (bone, gallbladder, and pancreas) of chicks fed excess inorganic Mn (1000 mg/kg provided as MnSO4 . H2O). Corn, SBM, FM, and WB also reduced tissue Mn levels at the chick's minimal dietary Mn requirement (14 mg/kg) when fed a casein-dextrose diet. In fact, as little as 1.0% WB, 2.5% FM, and 5.0% of a corn-SBM combination were capable of markedly reducing tissue Mn concentrations. Rice bran, however, appeared to provide bioavailable Mn when added to diets containing a level of Mn at or below the chick's requirement.

Animal Feed↗

PubMed1986

Long-term effects of corn, soybean meal, wheat bran, and fish meal on manganese utilization in the chick.

A 7-week assay was conducted to investigate the long-term effects of several natural feed ingredients on Mn utilization. Chicks were fed a Mn-deficient casein-dextrose diet supplemented with fish meal, wheat bran, or a corn-soybean meal mixture. Although these feed ingredients contain significant quantities of Mn, they actually depressed performance and reduced the Mn concentration in key tissues when dietary Mn was near the chick's minimal requirement. At deficient levels of dietary Mn, fish meal also had detrimental effects on those parameters, and it increased the severity of perosis as well.

Animal Feed↗

PubMed1986

Further investigation of the dietary protein and monensin level interrelationship in broiler chicks: influence of Eimeria acervulina infection, increased dietary protein, and level of feed intake.

Three experiments were conducted to evaluate the influence of several dietary factors on the monensin response in commercial broiler chicks fed corn-soybean meal diets varying in crude protein (CP). All experiments were conducted between 8 and 22 days posthatching. Trial 1 had a 2 X 2 X 2 factorial design wherein diets containing 16 or 24% CP and 0 or 121 mg/kg monensin were fed in the presence and absence of Eimeria acervulina infection. The monensin-induced growth depression was greater at 16% CP than at 24% CP. Coccidial infection had no effect on the monensin X protein level interaction. Monensin supplementation markedly improved performance of chicks infected with E. acervulina. Trial 2 was conducted to determine if the monensin-induced depression in performance caused by feeding a high level of monensin (140 mg/kg) could be moderated by feeding a high protein diet. Monensin supplementation reduced growth rate 18 and 10% in chicks fed 20 and 24% CP, respectively. Increasing CP to 28% alleviated the adverse effects of monensin on weight gain. Pair-feeding was used in Trial 3 to determine the extent to which the monensin-induced growth depression observed in chicks fed low protein diets was due to reduced feed intake. As expected, reducing the dietary CP from 24 to 16% resulted in a marked increase in the growth depression caused by 121 mg/kg monensin. Pair-feeding indicated that most of monensin's adverse effects in low protein diets could be attributed to its anorexic properties.

Animals↗

PubMed1986

Utilization of isomers and analogs of amino acids and other sulfur-containing compounds.

Rats and chicks obtain little or no bioefficacy from the D-isomers of lysine, threonine, arginine, histidine and cystine. D-isomers of the branched-chain amino acids, i.e., leucine, isoleucine and valine (LEU, ILE, VAL) are utilized relatively well by chicks but poorly by rats. D-tryptophan is utilized efficiently by rats and pigs, but inefficiently by chicks, poults, mice and humans. The D-forms of phenylalanine (PHE), tyrosine and methionine (MET) are utilized well by both rats and chicks. Keto and hydroxy analogs of LEU, ILE, VAL, PHE and MET are utilized by both rats and chicks. The L-isomer of the alpha-hydroxy analogs of ILE and PHE has bioactivity while the D-isomer has no bioactivity. D-OH-LEU and D-OH-VAL have bioactivity, but they are less efficacious than their corresponding L-OH analogs. D-OH-MET is a more efficient precursor of L-MET than is L-OH-MET. In general, alpha-keto analogs of LEU, ILE, VAL, PHE and MET are utilized no more efficiently than the active isomeric form of the alpha-OH analogs of these amino acids. The alpha-OH and alpha-keto analogs of ILE are utilized relatively efficiently when used to replace only a portion of L-ILE in a purified amino acid diet for either rats or chicks; utilization of L-ILE analogs is poor, however, when all of the dietary L-ILE is replaced by analog material. In addition to MET and cyst(e)ine, many other dietary sulfur compounds must be considered when dealing with sulfur amino acid bioactivity. Glutathione, taurine, N-acetyl-MET, lanthionine and inorganic sulfate all have sulfur amino acid bioactivity under certain circumstances. Likewise, both oral and endogenous carnosine have histidine bioactivity, and purines, pyrimidines and urea have dispensable amino acid biosynthetic activity.

Amino Acids↗

PubMed1985

Transmethylation of homocysteine to methionine: efficiency in the rat and chick.

Experiments were conducted with young chicks and rats to quantify the efficacy of L-homocysteine as a methionine precursor. Linear growth responses were obtained to both L-methionine and L-homocysteine when added to a methionine-deficient intact-protein diet containing a plethora of cystine. Slope-ratio multiple regression methodology indicated L-homocysteine to be 64.5% as efficacious as L-methionine in rats and 62.5% as efficacious in chicks. Plasma-free methionine also increased linearly as graded levels of either L-methionine or L-homocysteine were added to the diet of rats. At higher dosages of L-homocysteine, betaine, but not choline, showed some efficacy in enhancing the conversion of homocysteine to methionine. In the linear response surface of the growth curve, however, supplemental betaine was without effect on L-homocysteine bioefficacy, as was also the case for supplemental sarcosine and N5-methyltetrahydrofolic acid.

Animals↗

PubMed1985

Antagonism of arginine by excess dietary lysine in the growing dog.

Experiments were conducted with growing English Pointer puppies to examine the effects of ingesting excess lysine. A purified crystalline amino acid basal diet containing 0.40% L-arginine (the arginine requirement for maximal weight gain) and 0.91% L-lysine was fed in all assays. All diets were kept isonitrogenous by the addition of diammonium citrate, and lysine was supplied as L-lysine acetate. Both weight gain and gain/feed were reduced in the presence of 4% excess dietary lysine. However, 1 and 2% excess supplemental lysine had no effect on performance. In a second experiment, a growth response to supplemental arginine was obtained in the presence, but not in the absence, of a growth-depressing level of lysine (4%). Therefore, lysine appeared to depress growth by antagonizing arginine. The mechanism of the lysine-arginine antagonism was examined in a third experiment. Classic signs of arginine deficiency: orotic aciduria, depressed urea formation, hyperammonemia, a reduction in weight gain, and emesis were observed in puppies consuming excess lysine but not in their pair-fed controls. Excess lysine ingestion neither inhibited nor induced liver arginase, but it did result in a generalized amino aciduria early in the experiment. In addition, lysine did not appear to affect arginine absorption. Therefore, the mechanism behind the lysine-arginine antagonism in the dog remains to be elucidated.

Amino Acids↗

PubMed1985

Reduction of liver copper concentration by the organic arsenical, 3-nitro-4-hydroxyphenylarsonic acid.

The interaction between 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) and Cu was studied in a series of experiments with crossbred, broiler-type chicks. A fully fortified corn-soybean meal diet was fed in all assays. While roxarsone caused a marked reduction in liver Cu concentration, arsanilic acid (4-aminophenylarsonic acid), As2O3 and As2O5 were without effect. When structural analogs of roxarsone were studied, it was found that o-nitrophenol and 3-nitro-4-hydroxybenzoic acid also had no effect on liver Cu concentration in birds fed a high level of Cu. However, liver Co concentration was reduced by the addition of either o-nitrophenol or roxarsone to the diets of birds fed a high level of Co. It was concluded that arsenic per se had no effect on liver Cu accumulation or depletion, but that a chelate was probably formed between Cu or Co and the nitroso and hydroxyl groups of the ring portion of roxarsone. In addition to the reduction in liver Cu deposition, concentrations of Cu in the bile, brain, heart and pancreas of chicks were reduced by the addition of roxarsone to a high-Cu diet. Neither dietary nor intraperitoneally (ip) injected roxarsone had an effect on liver Cu concentration when Cu was injected ip. Therefore, both roxarsone and Cu had to be present in the diet for the liver Cu-lowering effect of roxarsone to be exerted. A further experiment was conducted with growing rats to determine the effect of roxarsone on Cu balance. Feeding roxarsone elevated Cu excretion in the urine but had no effect on Cu excretion in the feces.

Animals↗

PubMed1985

Feed additive studies with newly weaned pigs: efficacy of supplemental copper, antibiotics and organic acids.

Six experiments involving 706 newly weaned 28- to 32-d-old pigs were conducted to evaluate the efficacy of copper (Cu) sulfate (to provide 250 mg/kg Cu), antibiotic-sulfa combinations [chlortetracycline, 110 mg/kg + penicillin, 55 mg/kg + sulfamethazine, 110 mg/kg; i.e., Aureo-Sulfa-Penicillin (ASP) or tylosin, 110 mg/kg + sulfamethazine, 110 mg/kg; i.e., Tylosin-Sulfa (TS)] and anhydrous citric or fumaric acid (.75 to 1.5% of the diet). The basal experimental diet was a 19% crude protein (CP)-fortified corn-soybean meal diet (1.08% lysine) containing 7% dried whey and 3% fish meal. Marked and consistent gain and gain/feed responses occurred from the Cu supplement, particularly during the first week postweaning. The antibiotic-sulfa combinations were less efficacious than Cu during the 1-wk postweaning stress period. During either the 1- or 3-wk growth periods, ASP and TS showed additivity with Cu in promoting rate and efficiency of weight gain. Liver Cu was increased by Cu addition to the diet, but neither ASP nor TS affected Cu deposition in the liver. In a factorial experiment involving 17% (1.01% lysine) or 20% CP (1.23% lysine) corn-soybean meal diets containing either no dried whey or an addition of 25% whey, Cu supplementation elicited marked improvements in rate and efficiency of weight gain, particularly in diets without added whey. Likewise, whey addition improved pig performance, especially when added to the diets containing no supplemental Cu.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

A comparison of methods for organ-weight data adjustment in chicks.

An experiment was conducted with 168 Arbor Acre X Peterson unsexed, crossbred broiler chicks to compare methods of expressing organ-weight data and to assess changes in organ weights and physiological parameters as body weight (97 to 791 g) and age (5 to 26 days) increased. Actual wet weight of liver, heart, intestine, spleen, and pancreas and percent bone ash increased (P less than .01) as age and body weight increased. Tibia length-to-width ratio decreased (P less than .01) as age and body weight increased. Blood hemoglobin, hematocrit, and plasma protein were not affected (P greater than .1) by age or by body weight. Liver, heart, and intestinal weight decreased (P less than .01) and spleen weight increased (P less than .01) as body weight and age increased when these tissue weights were expressed as percent of body weight. Liver weight adjusted for body weight by covariance analysis, however, remained constant; adjusted heart and intestinal weights decreased (P less than .01), and adjusted spleen weights increased (P less than .01) with increasing age and body weight. The covariate, body weight, was not significant (P greater than .1) for pancreas weight, tibia length-to-width ratio, and percent bone ash. Except for spleen, adjustment by covariance analysis more effectively reduced variation due to body weight than did expression as percent of body weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗