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Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 145 records · Page 8Linked to original sources
PubMed1991

Manganese and iron interrelationship in the chick.

Experiments were conducted to investigate the Mn-Fe interrelationship in the chick. Graded levels of Fe and two levels of Mn were added to a corn-soybean meal diet (157 mg Mn/kg; 372 mg Fe/kg) and to an Fe-deficient casein-dextrose diet containing 15.4 mg Mn/kg and 5.0 mg Fe/kg. Dietary Fe had little effect on the Mn status of the chick, regardless of the level of Fe supplementation. Conversely, Mn supplemented at 1,000 mg/kg reduced blood hemoglobin concentration, but only when the dietary Fe level was at or below the chick's requirement. Levels of supplemental Fe up to 2,500 mg/kg had no effect on performance of chicks fed the corn-soybean diet, but a supplemental level of 5,000 mg Fe/kg diet reduced both weight gain and bone ash concentration. These data suggest that the interaction between Mn and Fe in the chick is a unidirectional phenomenon, in which excess Mn impairs Fe utilization but excess Fe does not antagonize Mn.

Animals↗
PubMed1991

Research note: bioavailability of copper in cupric oxide, cuprous oxide, and in a copper-lysine complex.

Young chicks were used in a 2-wk feeding study to evaluate Cu bioavailability (relative to CuSO4.5H2O used as a reference standard) in analytical grade CuO, Cu2O, and in a feed-grade Cu-lysine complex. A basal corn and soybean meal diet was formulated to contain 290 mg Cu/kg, and graded levels (0, 75, and 150 mg/kg) of supplemental Cu were added from each Cu source. Based upon accumulation of Cu in the liver, Cu2O and Cu-lysine furnished Cu as efficiently as CuSO4.5H2O, but CuO provided no bioavailable Cu to the chicks.

Animals↗
PubMed1991

Research note: effect of excess lysine, methionine, threonine, or tryptophan on production performance of laying hens.

An experiment was conducted with laying hens to determine effects of feeding excesses of several individual amino acids in a practical layer diet. Single Comb White Leghorn hens, which were in peak production (31 wk of age), were assigned to one of five dietary treatments: a 16% CP corn and soybean meal positive control diet, or this diet fortified with 1% additional L-Lys, 1% additional DL-Met, 1% additional L-Thr, or 1% additional L-Trp. The diets were fed for ad libitum intake for 4 consecutive wk of production. For the entire production period, hen-day egg production, egg yield, and feed intake were not significantly different among any of the treatments. The study indicated that considerable tolerance exists in high-producing laying hens for individual excesses of the amino acids commonly used as supplements in poultry diets.

Analysis of Variance↗
PubMed1991

Partitioning of nutrients for growth and other metabolic functions: efficiency and priority considerations.

The raw materials for proteinaceous growth in the avian are amino acids supplied from protein ingestion and from body protein degradation. Maximal efficiency of utilization (i.e., retention) of absorbed nitrogen approximates 76%. This occurs when a well-balanced mixture of amino acids is ingested. The utilization efficiency of individual dietary amino acids varies around the 76% figure, with slow-turnover amino acids such as lysine being used more efficiently (80%) than fast-turnover amino acids such as isoleucine (61%). A paucity of information exists on metabolic priorities for amino acids at various levels of amino acid deficiency. It is clear, however, that dietary histidine is used with priority for protein synthesis before it is shunted toward carnosine or anserine biosynthesis. Likewise, cysteine use by chicks for growth has priority over cysteine use for glutathione (GSH) biosynthesis. With a cysteine-free diet containing the minimal methionine requirement for maximal growth, hepatic GSH is depressed and remains low and unchanged until about 30% of the growth need for cysteine is satisfied, at which point GSH begins accumulating rapidly. In rats, liver GSH begins accumulating rapidly even with very small doses of cysteine. This suggests that the metabolic priority for cysteine in rats is as great for GSH synthesis as it is for growth.

Amino Acids↗
PubMed1991

Lysine requirements of fast- and slow-growing broiler chicks.

Experiments were conducted to determine the lysine requirement of fast-growing (Hubbard x Hubbard) and slow-growing (New Hampshire x Columbian) broiler chicks during the period 8 to 21 days posthatching. A lysine-deficient diet (.51% digestible lysine; 23% CP; 3,200 kcal MEn/kg) based upon corn, feather meal, and soybean meal was supplemented with 10 graded increments of L-lysine.HCl to produce three- to fourfold responses in weight gain. Requirements for digestible lysine were determined to be not greater than 1.01% of the diet for maximal weight gain of both strains. Maximal gain:feed ratio was achieved in both strains at a digestible lysine level not greater than 1.21% of the diet. Daily feed consumption of the fast-growing strain was over twice that of the slow-growing strain, and the digestible lysine requirement for maximal feed efficiency was 675 mg/day for fast-growing chicks compared with 318 mg/day for slow-growing chicks. The portion of the weight gain comprised of protein was roughly the same in both strains. It is evident that the slow-growing crossbred broiler strain. Translating the digestible lysine requirement of 1.21% of the diet to practice, wherein a corn and soybean meal diet would be fed, results in a total lysine requirement of 1.41% of the diet (for maximal feed efficiency) during the broiler chick's 2nd and 3rd wk of life.

Animal Feed↗
PubMed1991

Histidine and tryptophan requirement of growing chicks.

Experiments were conducted to determine the His and Trp requirement of broiler chicks during the period 8 to 22 days posthatching. A His- or Trp-deficient diet (.32% total His; .18% total Trp; 25% CP; 3,200 kcal MEn/kg) based upon corn, feather meal, and soybean meal was supplemented with graded increments of either L-His.HCl.H2O or L-Trp to produce growth responses. Growth rate and feed efficiency of birds fed the fully fortified experimental diet were similar to those of birds fed a corn and soybean meal positive control diet (23% CP; 3,200 kcal MEn/kg). True digestibility of the protein blend (corn, feather meal, and soybean meal) used in the basal diet was 81.4% for His and 83.3% for Trp as established in precision-fed, cecectomized adult cockerels. Requirements for digestible His and Trp were determined to be not greater than .31% (1.24% of CP) and .20% (.80% of CP), respectively, for maximal weight gain and feed efficiency. Translating the requirement estimates to practice, wherein a 23% corn and soybean meal diet would be fed, results in a total His requirement of .32% and a total Trp requirement of .22% of the diet during the broiler chick's 2nd and 3rd wk of life.

Animal Feed↗
PubMed1990

L-2-oxothiazolidine-4-carboxylate as a cysteine precursor: efficacy for growth and hepatic glutathione synthesis in chicks and rats.

Chick and rat experiments were conducted to determine the efficacy of L-2-oxothiazolidine-4-carboxylate (OTC) as a cysteine (Cys) precursor for growth and hepatic glutathione (GSH) biosynthesis. Isosulfurous graded increments of OTC and Cys were added to Cys-free purified amino acid diets that were adequate in methionine. Curvilinear responses to both Cys and OTC for chicks and rats were obtained. Hepatic GSH accumulated in chicks only at dietary Cys levels above 0.10%. In rats, hepatic GSH increased linearly as dietary Cys content increased from deficient to adequate and from adequate to excessive. Utilization of OTC by chicks was as efficacious as isosulfurous levels of Cys for growth and hepatic GSH biosynthesis. In rats, OTC was slightly inferior to Cys for growth and hepatic GSH biosynthesis. Exponential regression slope-ratio growth efficacy values for OTC were 78.5% for chicks and 70.2% for rats; multiple linear regression slope-ratio GSH biosynthesis efficacy values were 80.3% for chicks and 83.7% for rats. It is concluded that orally administered OTC is active as a Cys precursor.

Administration, Oral↗
PubMed1990

Nutritive value of oat flour and oat bran.

Oat flour, the by-product resulting from commercial production of oat bran, was analyzed to contain 7.7% moisture, 11% CP, 6% crude fat, 8.8% NDF, 1.56% ash (.10% Ca, .23% P), 4,265 kcal/kg GE, .41% lysine, .36% threonine, .17% tryptophan, .21% methionine and .34% cystine. Chick bioassays revealed that lysine and threonine were the first- and second-limiting amino acids in oat flour. Slope-ratio protein quality assessment indicated that the protein quality of oat flour was similar to that of dehulled soybean meal. True ME (corrected for N retention, i.e., TMEn) of oat flour for adult cockerels was 3,726 kcal/kg. A P bioavailability assay with chicks indicated that the P in oat flour was 59.7% bioavailable relative to a KH2PO4 standard. Oat bran was analyzed to contain 9.7% moisture, 15% CP, 6.2% crude fat, 19.2% NDF, 2.33% ash (.12% Ca, .41% P), 4,316 kcal/kg GE, .59% lysine, .47% threonine, .18% tryptophan, .24% methionine and .44% cystine. Protein quality assessment in chicks indicated that the protein quality of oat bran was similar to that of dehulled soybean meal. True MEn of oat bran was found to be 3,449 kcal/kg. Of the .41% total phosphorus in oat bran, 42.2% was bioavailable, relative to the KH2PO4 standard.

Amino Acids↗
PubMed1990

Zinc bioavailability in feed-grade sources of zinc.

Chick bioassays were used to assess bioavailability of zinc (Zn) from inorganic Zn sources. A soy isolate-dextrose diet containing 13 mg Zn/kg diet was supplemented with feed-grade sources of ZnSO4.H2O (ZnSO4) or ZnO and fed for 2 wk after a 7-d Zn-depletion protest period. Bioavailability of Zn in ZnO relative to ZnSO4 (set at 100%) was determined by multiple regression slope-ratio methodology, using both growth and tibia Zn accumulation in chicks fed graded levels of ZnO and ZnSO4. Linear responses for gain and tibia Zn occurred at dietary Zn levels (ZnSO4.7H2O) between 13 mg/kg (basal) and 33 mg/kg (gain) or 53 mg/kg (total tibia Zn). Therefore, two bioavailability assays were conducted using supplemental Zn levels of 0, 7.5 and 15 mg/kg from each Zn source. When weight gain was regressed on supplemental Zn intake, bioavailability of Zn in ZnO was only 61.2% (P less than .01) that of ZnSO4. When total tibia Zn was regressed on supplemental Zn intake, bioavailability of Zn compared with ZnSO4 (set at 100.0%) was 44.1% (P less than .001) for ZnO. With chicks fed soy-based diets, bioavailability of Zn from ZnO was less than that of ZnSO4.

Animal Feed↗
PubMed1990

Phosphorus utilization in chicks fed hydrated sodium calcium aluminosilicate.

Two experiments were conducted to evaluate the effects of hydrated Na Ca aluminosilicate (HSCAS) on P utilization of young broiler chicks. Phosphorus-deficient corn-soybean meal diets containing .36% (.134% available) P and 1% Ca were fortified with 0, .05 and .10% P provided as KH2PO4 (22.8% P) or feed-grade dicalcium phosphate (18.9% P). Diets were available ad libitum to chicks receiving 0, .50 or 1.0% HSCAS during the period 8 to 22 d posthatching. Weight of tibia ash, percentage of tibia ash and bone-breaking force were regressed on supplemental P intake to assess P utilization in the absence or presence of HSCAS. Tibia parameters (ash weight, percentage of ash and bone-breaking force) responded linearly (P less than .01) to P supplementation. Regardless of P source (KH2PO4 or dicalcium phosphate), .5% or 1.0% HSCAS had no effect (P greater than .1) on P utilization. With no supplemental P, tibia parameters also were not affected (P greater than .05) by HSCAS. Phosphorus utilization from dicalcium phosphate was estimated to be 87% as efficient as that observed for KH2PO4. The results suggest that dietary HSCAS does not impair utilization of either phytate or inorganic P.

Aluminum Silicates↗
PubMed1990

Absorption and bioavailability of DL-methionine hydroxy analog compared to DL-methionine.

Intestinal absorption of crystalline DL-methionine (DL-MET) and DL-methionine hydroxy analog calcium (DL-HMA) were determined in a true-digestibility-balance assay using cecectomized (CEC) and sham-operated conventional (CONV) cockerels. The treatments consisted of fasted birds and birds crop-intubated (CI) with 30 g of a corn-soybean meal basal diet (16% CP) supplemented with 0, .2, or .4% of DL-MET or equimolar levels of DL-HMA. There was no detectable free D-MET or L-MET or HMA in the excreta of fasted birds or of those fed the unsupplemented basal diet. The intestinal absorption of DL-HMA was 95.9 +/- .8% (means +/- SE) for CEC and 98.8 +/- .8% for the CONV cockerels. The absorption of DL-MET was approximately 99.7 +/- .2% for the CEC and the CONV cockerels. In a second experiment procedures were developed for a bioavailability assessment by comparing the growth responses to CI and intraperitoneal-injected (IP) DL-MET or DL-HMA in chicks fed a crystalline-amino-acid diet deficient in methionine. Graded increments of pH-adjusted DL-MET or DL-HMA (in water solutions) were administered twice daily in a 7-day growth assay. Slope-ratio analysis indicated that bioavailability (+/- SE) of CI DL-HMA was 91.3 +/- 11.8% relative to the CI DL-MET on an equimolar basis. The bioavailability of CI DL-HMA was similar to that of IP DL-HMA, indicating that the intestinal absorption of DL-HMA was highly efficient.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1990

Manganese utilization in chicks as affected by excess calcium and phosphorus ingestion.

Three experiments were conducted to assess Mn utilization in the presence or absence of excess Ca and P from various sources. Supplements were added to a corn-soybean meal diet containing 1% Ca, .7% (.5% available) P and 37 mg of Mn per kg. Three percentages of supplemental Mn from MnSO4.H2O (0, 500, and 1,000 mg of Mn per kg) were used to construct a standard curve of tibia Mn regressed on the 14-day supplemental Mn intake (r averaged .96 for the three experiments). From this, the tibia Mn values obtained from chicks fed diets containing 1,000 mg of supplemental Mn per kg of diet plus 1% added Ca from various sources, were used to calculate bioavailable Mn via standard-curve methodology. In Experiment 1, analytical-grade (AG) CaCO3, feed-grade (FG) oyster shell and FG dicalcium phosphate decreased Mn utilization by 20, 15 and 53%, respectively, but FG limestone was without effect. Experiments 2 and 3 were conducted to determine how different combinations of Ca and P, as well as different cationic forms of P, affected Mn utilization. The results from these experiments indicated that feeding .88% of excess inorganic P, regardless of source and whether fed alone or in combination with excess Ca, reduced Mn utilization by 50 to 65%. Among the Ca sources, only oyster shell caused a reduction in Mn utilization. It is evident that excess dietary P is more antagonistic to Mn than is excess Ca.

Animals↗
PubMed1990

Effect of varying calcium and phosphorus level on manganese utilization.

Two experiments were conducted to evaluate the effect of varying levels of excess Ca and P on manganese (Mn) utilization. The criterion used to study the Mn-antagonizing effects of excess Ca and P was the regression of total tibia Mn on supplemental Mn intake. In Experiment 1, high supplemental levels of Mn were fed (0, 500, and 1,000 mg Mn per kg); in Experiment 2, lower Mn levels were fed (0, 50, and 100 mg Mn per kg). Supplements were added to a corn-soybean meal diet containing 1.1% Ca, .7% (.5% available) P, and 37 mg Mn per kg. In Experiment 1, a 3 x 3 x 3 factorial arrangement of treatments (four replicates) was used. Treatments were as follows: 0, .5, and 1.0% excess Ca as feed-grade ground limestone; 0, .4, and .8% excess P as KH2PO4; and 0, 500, and 1,000 mg Mn per kg as MnSO4.H2O. Total tibia Mn was depressed by P (P less than .0001) but not by Ca (P greater than .05). Compared with the standard (no added P), .4% P reduced Mn utilization by 22%, whereas .8% P reduced it by 38%. Manganese supplementation was found to ameliorate the growth-depressing effect of .8% supplemental P. Results of Experiment 2 agreed with the results in Experiment 1, providing evidence that bioavailability estimates obtained from experiments containing high levels of Mn can be extrapolated to diets containing lower levels. Results from Experiment 2 indicated that, relative to the standard (no added P), .22, .44 and .88% excess P reduced Mn utilization by 16, 22 and 31%, respectively.

Animals↗
PubMed1990

Riboflavin requirement of chicks fed purified amino acid and conventional corn-soybean meal diets.

Three experiments were conducted to determine the riboflavin requirement for maximal growth of young chicks. Graded levels of crystalline riboflavin were added to either riboflavin-free, purified amino acid diets or corn-soybean meal diets. Chick growth responses were obtained upon adding riboflavin to both diets. Chicks fed the purified diet required 1.8 mg of riboflavin per kg of diet, but those fed the corn-soybean meal diet required 2.63 mg of riboflavin per kg of diet. Retarded growth and leg paralysis, rather than curled-toe paralysis, were the predominant signs of riboflavin deficiency. Calculations suggested that riboflavin bioavailability in the corn-soybean meal diet was 59.1%.

Amino Acids, Essential↗
PubMed1990

Hydrated sodium calcium aluminosilicate: effects on zinc, manganese, vitamin A, and riboflavin utilization.

Three experiments were conducted to evaluate effects of hydrated sodium calcium aluminosilicate (HSCAS, a phyllosilicate) on Zn, Mn, vitamin A, and riboflavin utilization in young broiler chicks. In Experiment 1, addition of either .5% or 1.0% HSCAS to practical corn-soybean meal diets had no effect (P greater than .05) on total tibia Mn content or total liver vitamin A concentration. Total tibia Zn decreased slightly, but linearly (P less than .05), as level of HSCAS increased. Graded increments of riboflavin (0, .6 and 1.2 mg per kg of diet) were added to a riboflavin-free purified amino acid diet to assess riboflavin utilization as affected by HSCAS in Experiments 2 (.5% HSCAS) and 3 (1.0% HSCAS). Linear growth responses to riboflavin were obtained in the absence and presence of HSCAS. Common intercept multiple-linear regression indicated that riboflavin utilization was not affected (P greater than .05) by .5% or 1.0% HSCAS. The results suggest that .5% or 1.0% dietary HSCAS does not impair Mn, vitamin A, or riboflavin utilization, but that Zn utilization is reduced slightly as a result of HSCAS ingestion.

Aluminum Silicates↗
PubMed1989

Methionine requirement of the finishing pig.

Two pig experiments were conducted using a methionine (Met)-deficient feather meal-corn-soybean meal basal diet (13% CP; 3,400 kcal ME/kg diet, .126% Met, 456% cystine) supplemented with an amino acid mixture (lysine, tryptophan, histidine, threonine and phenylalanine) to determine the Met requirement of finishing pigs between 50 and 80 kg live weight. Using young chicks in a Met bioavailability growth assay and cecectomized adult cockerels in a Met digestibility assay, the Met-deficient basal diet was found to contain .115% bioavailable and .110% digestible Met. These results gave a bioavailability estimate (relative to DL-Met set at 100%) of 91.3 +/- 2.5% and a true digestibility estimate of 87.0 +/- 2.2% for Met in the basal pig diet. In Exp. 1, 21 crossbred pigs averaging 61 kg initially were individually fed diets containing .115, .165 or .215% bioavailable Met for 21 d. Average daily gain and gain:feed ratio increased quadratically (P less than .05) as level of Met increased. In Exp. 2, 30 crossbred pigs averaging 53 kg were individually fed diets containing .115, .135, .155, .175 or .195% bioavailable Met for 27 d. Daily gain and gain;feed ratio responded linearly (P less than .01) as Met level increased. Based on the results of Exp. 2, the bioavailable Met requirement of finishing pigs in the weight range 50 to 80 kg was estimated to be .182% of the diet. Assuming an 88% bioavailability of Met in commercial diets based on corn and soybean meal, the total Met level needed in practice would be .207%. If 55% of the finishing pig's sulfur amino acid need can be furnished by cystine, the total sulfur amino acid requirement would be .45% of the diet.

Analysis of Variance↗
PubMed1989

Amelioration of selenium toxicity by arsenicals and cysteine.

Young chicks exhibited a 61% reduction in weight gain when a corn-soybean meal diet was supplemented with 15 mg/kg Se provided as Na selenite. The same level of Se provided as selenomethionine depressed weight gain by 32%. Supplementing the high selenite diet with isoarsenous (14 mg/kg As) additions of As2O5, As2O3, phenylarsonic acid, phenylarsine oxide and roxarsone ameliorated the Se-induced growth depression: As2O5 almost totally restored growth rate; As2O3, phenylarsonic acid and phenylarsine oxide gave intermediate responses; and roxarsone gave only a small ameliorative growth response. Arsanilic acid was without effect in stimulating growth rate of selenite-intoxicated chicks. Dietary addition of .4% L-cysteine produced a growth response in selenite intoxicated chicks that was somewhat greater than that obtained with roxarsone; administering both roxarsone and cysteine corrected growth better than either compound given singly. Both roxarsone and As2O5 also effectively ameliorated the Se-toxicity growth depression caused by selenomethionine (15 mg Se/kg) supplementation, but cysteine showed no efficacy against morbidity caused by this form of Se. Liver Se concentration was elevated 10-fold by selenite and 25-fold by selenomethionine supplementation. The arsenic compounds had varying effects on liver Se, whereas cysteine tended to increase Se concentration. These findings suggest that both inorganic and organic arsenicals as well as cysteine ameliorate selenium toxicity by different mechanisms.

Animal Feed↗