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D H Baker

Publications and source records attributed to D H Baker.

At least 109 records · Page 6Linked to original sources
PubMed1994

Dietary L-homoarginine has no lysine bioactivity in chicks.

A chick growth assay was conducted to investigate the effect of dietary L-homoarginine supplementation on performance of chicks fed a Lys-deficient corn-feather meal diet. Weight gain, feed intake, and feed efficiency increased linearly (P < .01) as Lys was added at .1 and .2% from feed-grade L-Lys.HCl. Adding homoarginine at .2% resulted in less (P < .05) weight gain and feed intake than observed in chicks fed the unsupplemented basal diet. These data suggest that dietary homoarginine had no Lys bioactivity, but may also have antagonized Lys utilization from the basal diet.

Animals↗
PubMed1994

Limiting order of amino acids in corn and soybean meal for growth of the chick.

Several experiments were conducted with crossbred chicks during the period 8 to 22 d posthatching to establish the limiting order of amino acids (AA) in corn and dehulled soybean meal (SBM) and in a corn-SBM mixture. Cecectomized adult cockerels were used to determine true AA digestibilities in both corn and SBM, and AA fortification levels were based upon bringing digestible AA levels to their ideal levels (expressed as a percentage of CP). Ideal ratios (percentage of lysine) used were Lys, 100; sulfur AA (SAA), 72; Arg, 105; Val, 77; Thr, 67; Trp, 16; Ile, 67; His, 37; Phe+Tyr, 105; and Leu, 111. Diets were fed at 10% CP, but they contained corn or SBM in amounts that would just meet the ideal concentration of the AA in greatest excess (Leu for corn; Phe for SBM). Thus, the corn diets contained only 5.6% CP from corn whereas the SBM diets contained only 8.0% CP from SBM. Diets were adjusted to 10% CP from AA additions, with glutamate varying as necessary. The limiting order of AA in corn was 1) Lys, 2) Thr, 3) Trp, 4) Arg, Ile, and Val, 5) Met+cystine, 6) Phe+Tyr, and 7) His. In SBM, the limiting order was 1)Met+cystine, 2) Thr, 3) Lys and Val, 4) nonspecific amino nitrogen, and 5) His. The order of limiting AA in the corn-SBM mixture was 1) Met, 2) Thr, 3) Lys, 4) Val, 5) Arg, and 6) Trp.

Amino Acids↗
PubMed1993

Effects of exercise training on diet-induced lipogenic enzymes and body composition in rats.

It is well known that a carbohydrate-rich diet promotes lipogenesis via induction of hepatic lipogenic enzymes, whereas chronic physical exercise reduces body fat. The purpose of this study was to investigate whether exercise training can decrease diet-induced hepatic lipogenic enzymes and total body fat composition. Female Sprague-Dawley rats were randomly divided into exercise trained (T) and sedentary (S) groups. Training was performed on a treadmill for 8 weeks for up to 25 m/minute, 15% grade for 90 minutes/day, 5 days/week. The T and S groups were further divided into four dietary treatments. Fifty percent of the calories for each diet were from a basal ingredient and the other 50% were from either cornstarch (C), glucose (G), fructose (Fr), or fat (Fa). T significantly decreased body fat and increased body water content in all dietary groups (p < 0.01), but had no effect on body weight. Fr rats had significantly heavier liver weight than did the remaining groups. Activities of hepatic fatty acid synthase, ATP-citrate lyase (CL), malic enzyme (ME), pyruvate kinase, and glucose-6-phosphate dehydrogenase were significantly higher in Fr and lower in Fa compared with C and G. Training significantly increased activities of CL and ME in Fa, but had little effect on these enzymes in other groups. These data suggest that the fat-reducing effect of conventional exercise training is elicited by regulatory mechanisms other than by a reduction of hepatic lipogenic enzymes.

Acetyl-CoA Carboxylase↗
PubMed1993

Quantitative efficacy of niacin sources for chicks: nicotinic acid, nicotinamide, NAD and tryptophan.

A niacin-deficient diet based upon corn and casein was used to establish growth-promoting efficacy of various sources of niacin activity. In the presence of excess dietary nicotinamide, chicks fed the corn-casein diet achieved maximal weight gain when 100 mg/kg of L-tryptophan was supplemented. The basal diet for efficacy studies therefore contained 100 mg/kg of added tryptophan and no supplemental nicotinic acid. Weight gain in the linear response surface of the growth curve proved to be a far better measure of niacin bioactivity than tissue accumulation of NAD(P). Slope-ratio growth efficacy studies indicated that excess dietary tryptophan was 1.94 +/- 0.14% as efficient as nicotinic acid in furnishing bioavailable niacin activity (52:1, wt:wt). Relative to nicotinic acid used as a standard (100%), nicotinamide bioactivity was 124%. Nicotinamide in NAD was utilized with an efficiency of 95% relative to nicotinamide per se.

Analysis of Variance↗
PubMed1993

Bioavailable level and source of cysteine determine protein quality of a commercial enteral product: adequacy of tryptophan but deficiency of cysteine for rats fed an enteral product prepared fresh or stored beyond shelf life.

Young rats were used in bioassays designed to assess the protein quality and tryptophan as well as cystine adequacy of the enteral product TwoCal-HN that was either freshly prepared or had been stored (nonrefrigerated) in a warehouse for 10 mo (i.e., beyond shelf life). Based upon supplementation studies, cystine was observed to be the first-limiting amino acid in both fresh and expired TwoCal-HN, and tryptophan was not second limiting. Protein efficiency ratio (PER) of expired, but not fresh, TwoCal-HN was lower than that of the casein control diet, but with cystine supplementation, PER of the TwoCal-HN products was equal to or greater than the PER of the casein control. With a diet containing 10 g protein/100 g that also contained energy-furnishing ingredients simulating TwoCal-HN, maximal growth enhancement occurred with a supplement of 1 g cystine/kg diet. Both glutathione and N-acetyl-L-cysteine were observed to be equivalent to an isomolar level of L-cystine in stimulating growth. Using a chemically defined amino acid diet that was singly deficient in tryptophan, bioavailability of tryptophan was determined for casein, fresh TwoCal-HN, expired TwoCal-HN and D-tryptophan. Slope-ratio bioefficacy values relative to L-tryptophan (weight gain regressed on supplemental tryptophan intake) indicated that none of the experimental sources of tryptophan had bioavailabilities different from 100%. The results indicated that tryptophan did not deteriorate, as measured analytically or biologically, as a result of storing TwoCal-HN beyond shelf life.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Menadione nicotinamide bisulfite is a bioactive source of vitamin K and niacin activity for chicks.

Young chicks were fed a vitamin K-deficient soybean concentrate basal diet containing graded levels of menadione from menadione nicotinamide bisulfite (MNB) or menadione dimethyl-pyrimidinol bisulfite (MPB) to assess prothrombin time as a function of menadione intake. Prothrombin time decreased linearly as menadione dose increased from 0 to 400 micrograms/kg. Multiple linear regression slope-ratio calculations indicated that both sources of menadione were of equal potency. To assess niacin bioactivity of MNB, graded doses of nicotinamide (0 to 5 mg/kg) from MNB or nicotinamide were added to a niacin-deficient diet based upon corn, corn gluten meal and vitamin-free casein. Weight gain increased linearly as a function of nicotinamide dose, and multiple linear regression analysis of weight gain as a function of supplemental nicotinamide intake revealed no significant differences in slope between the two sources of nicotinamide. Using excess doses, MNB was compared with MPB in acute (single crop intubation) or chronic (fed in the diet for 14 d) toxicity trials. With a single menadione dose of 1600 mg/kg body wt, weight gain in the subsequent 14-d period was reduced by MNB but not by MPB. Mortality rates of 25 and 17% occurred for MPB and MNB, respectively, at this dose level. Doses lower than 1600 mg/kg body wt caused neither morbidity nor mortality. When provided in the diet for a 14-d feeding period, menadione doses of 3000 mg/kg diet from MNB reduced gain, feed intake, gain:feed ratio and blood hemoglobin concentration. Menadione doses of 6000 mg/kg diet were required to produce morbidity of this type when MPB was fed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1993

Biological efficacy of copper in chicken bile.

Newly hatched chicks were fed a Cu-deficient casein-soybean concentrate diet (0.56 mg Cu/kg) during an 8-d pretest period, after which they were fed experimental diets containing graded levels of added Cu from CuSO4.5H2O during a 15-d assay period. Following the Cu-depletion period, gall bladder Cu concentration decreased from 645 nmol/g dry matter at hatching to 60 nmol/g dry matter at d 8 posthatching; liver Cu concentration decreased during the same period from 255 to 225 nmol/g dry matter. During the subsequent 15-d repletion period, a sevenfold linear increase in gall bladder Cu occurred as Cu was supplemented up to 2 mg Cu/kg, after which it declined gradually in birds fed graded doses between 2 and 16 mg Cu/kg. Liver Cu also increased linearly as Cu was supplemented up to 2 mg/kg; when chicks were fed between 2 and 16 mg/kg of supplemental Cu, liver Cu concentration remained constant. Bile obtained from chicks fed 800 mg Cu/kg diet for 22 d was freeze-dried, analyzed and found to contain 3.05 mumol Cu/g dry matter. When 8-d-old Cu-depleted chicks were fed graded levels of supplemental Cu (0, 0.5 and 1.0 mg Cu/kg) from CuSO4.5H2O, bile Cu concentration increased linearly from 10.5 to 102.7 mumol/L. Bile Cu did not increase when freeze-dried bile (1.0 mg Cu/kg diet) was supplemented. When 0.5 mg Cu/kg from CuSO4.5H2O was supplemented in combination with 0.5 mg Cu/kg from freeze-dried bile, bile Cu concentration was less than one-half the level present in chicks fed 0.5 mg Cu/kg from CuSO4.5H2O alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Bioavailability of zinc in ground beef.

Based on zinc uptake in chick tibia, Zn bioavailability in cooked ground beef was equal to that of Zn in an inorganic standard (ZnSO4), whether Zn supplements were added to a soy-concentrate diet containing phytate or to a phytate-free egg-white diet. With both diet types, total tibia Zn was a linear (P < .01) function of supplemental Zn intake from ZnSO4, but the slope of the linear regression line was twice as great for the egg-white diet as for the soy-concentrate diet that contained phytate. At 10 mg/kg of supplemental Zn, freeze-dried ground beef produced the same tibia Zn concentration (and total Zn content) as that obtained with ZnSO4. The results suggest that the relative bioavailability of Zn in cooked ground beef is as great as that in ZnSO4, whether consumed in diets with or in those without phytate.

Animals↗
PubMed1993

Growth and plasma zinc responses of young pigs fed pharmacologic levels of zinc.

Three trials were conducted to evaluate high levels of Zn addition from various Zn sources on growth performance and plasma Zn responses of 8-kg pigs. Zinc supplements were added to 20% CP starting diets (125 mg of Zn/kg) containing antibiotics. Trial 1 was done to evaluate plasma Zn responses of pigs fed three different feed-grade Zn sources: ZnO where supplemental Zn levels were 0, 250, 500, 1,000, 3,000, and 5,000 mg/kg; ZnSO4 at 1,500 or 2,500 mg of Zn/kg; and a zinc-lysine complex (Zn-Lys) at 1,500 or 2,500 mg of Zn/kg. Plasma Zn concentration as a function of supplemental Zn intake was fitted to a broken-line for ZnO data and to simple linear models for ZnSO4 and Zn-Lys data. For ZnO, plasma Zn did not increase until concentrations > 1,000 mg Zn/kg were fed. Above this level, plasma Zn increased linearly (P < .01) for all three sources of Zn, although slopes of the ZnO and Zn-Lys response curves were 56% (P < .05) and 110%, respectively, of the ZnSO4 slopes. In Trial 2, five diets were fed: basal, 3,000 and 5,000 mg of Zn/kg from ZnO, and 3,000 and 5,000 mg of Zn/kg from ZnSO4. Daily gain and daily feed intake were increased (P < .05) by ZnO addition, regardless of level, whereas ZnSO4 addition increased these performance indices only at the 3,000 mg of Zn/kg level of supplementation. Plasma Zn responses to ZnSO4 addition were almost double those of ZnO addition.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Tryptophan requirement of pigs in the weight category 10 to 20 kilograms.

Experiments were conducted to determine the tryptophan (Trp) requirement of 10- to 20-kg pigs. A Trp-deficient experimental diet (.11% total Trp, 18% CP, 3,320 kcal of ME/kg) was composed of corn, feather meal, corn gluten meal, soybean meal, and dried whey. True digestibility of Trp in the experimental diet was 70% (.077% digestible Trp) as established in a digestibility assay that involved cecectomized, adult cockerels (Exp. 1). An initial pig study (Exp. 2) verified that the experimental basal diet, when fortified with sufficient L-Trp, was capable of producing growth rate and feed efficiency similar to that of pigs fed a conventional corn-soybean meal-dried whey diet (18% CP, 3,320 kcal of ME/kg). In Exp. 3, crossbred pigs with an average BW of 10.9 kg were fed the Trp-deficient basal diet supplemented with 0, .015, .030, .045, .060, and .075% L-Trp. In Exp. 4, crossbred pigs that averaged 9.5 kg were fed the basal diet fortified with .030, .045, .060, and .075% L-Trp. By examining the data from Exp. 3 and 4 together, the digestible Trp requirement for maximum daily weight gain was estimated to be .14% of the diet. Assuming an 88% true digestibility of Trp in commercial diets based on corn and soybean meal (calculated from published data), the total Trp required in practice would be .16% (.89% of the dietary protein).

Animal Feed↗
PubMed1993

Nutritional evaluation of copper-lysine and zinc-lysine complexes for chicks.

Three chick experiments were conducted to evaluate two mineral-Lys complexed products, Cu-Lys and Zn-Lys. Relative bioavailability of Lys, Cu, and Zn were assessed separately using diets specifically deficient in each of these nutrients and by employing criteria that respond in a straight-line fashion to supplementation with the nutrient in question. Common-intercept multiple linear regression (slope-ratio) of weight gain, bile Cu concentration, and total tibia Zn regressed on supplemental intake of Lys, Cu, and Zn, respectively, were used to assess bioavailability values relative to the standards (i.e., L-Lys.HCl, CuSO4.5H2O, and ZnSO4.H2O). Lysine bioavailability of Cu-Lys and Zn-Lys were estimated as 89 and 109%, respectively, which were not different (P > .05) from 100%. Relative bioavailability of Cu in Cu-Lys and Zn in Zn-Lys were estimated as 120 and 106%, respectively. These values were not different (P > .05) from the standards, i.e., CuSO4.5H2O for Cu and ZnSO4.H2O for Zn.

Animals↗
PubMed1993

Effects of sex, heat stress, body weight, and genetic strain on the dietary lysine requirement of broiler chicks.

Experiments were carried out to investigate the effects of sex, heat stress (37 C), body weight (heavy and light within strain), and strain of chicks on the dietary lysine requirement of chicks during 8 to 22 days posthatching. A lysine-deficient basal diet (.64% total lysine, 23% CP, 3,200 kcal ME(n)/kg) containing corn, feather meal, and soybean meal was supplemented with graded levels of L-lysine.HCl to produce growth response curves. The lysine-deficient diet contained .52% true digestible lysine as determined with a precision-fed cecectomized adult cockerel assay (Experiment 1). Hubbard x Hubbard chicks were used in Experiment 2 and New Hampshire x Columbian crossbred chicks were used in Experiments 3 and 4. Experiment 2 compared lysine requirements of male and female chicks. Weight gains between sexes were similar when diets were deficient in lysine, but males grew faster than females when lysine-adequate diets were fed. Male chicks required a higher level of dietary lysine than females for both maximal weight gain and feed efficiency. Also, regardless of sex, the lysine requirement (percentage of diet) for maximal feed efficiency was higher than that for maximal weight gain. In Experiment 3, heat stress reduced weight gain and feed intake of both males and females by about 22%, and it increased the lysine requirement of female but not male chicks. In Experiment 4, light and heavy chicks were selected from male and female populations. Heavy and light chicks exhibited the same dietary lysine requirement for maximal growth. However, the lysine requirement for maximal feed efficiency was higher for heavy birds than for light birds.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Effects of excess methionine or lysine for broilers fed a corn-soybean meal diet.

Three experiments were conducted to examine the consequences of over-supplementing DL-Met or L-Lys (as L-Lys.HCl) in diets for chicks fed a corn-soybean meal diet (23% CP, 3,200 kcal MEn/kg, .2% supplemental Met) during 1 to 3 wk posthatching. New Hampshire x Columbian male chicks were used in Experiments 1 and 2 and Hubbard x Hubbard males were employed in Experiment 3. The basal diet was supplemented with .5, 1.0, 2.0, or 4.0% DL-Met, or .4, .8, 1.6, or 3.2% L-Lys in Experiment 1. Weight gain, feed intake, and feed efficiency decreased linearly at supplemental levels of DL-Met between 1.0 and 4.0%. Weight gain of chicks fed diets with supplemental L-Lys levels greater than 1.6% was less than that of chicks fed the basal diet, but feed efficiency was not significantly affected. Adding K2CO3 to the diets containing 1.6 or 3.2% added L-Lys did not improve performance. Experiment 2 evaluated the effect of 1) adding 1.0% Gly or 1.0% L-Thr to the diet supplemented with 2.0% DL-Met; and 2) adding NaHCO3 to the high-Lys diets in order to buffer the excess chloride provided by L-Lys.HCl. Addition of these amino acids or buffer ameliorated but did not totally correct the negative effects of excess Met or Lys. Experiment 3 examined the tolerance of commercial broilers to supplemental DL-Met or L-Lys levels of .5 or 1.0%. Weight gain and feed efficiency were not affected by these excesses, but feed intake was reduced at the 1.0% level of inclusion of either amino acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1993

Bioavailability of copper in analytical-grade and feed-grade inorganic copper sources when fed to provide copper at levels below the chick's requirement.

Young chicks were fed a casein-soy protein concentrate basal diet (.56 mg Cu/kg) containing graded levels of added Cu (0, .5, 1.0 mg/kg) from analytical-grade (AG) CuSO4.5H2O, Cu2O, CuO, CuCO3.Cu(OH)2, CuCl, and also from feed-grade (FG) CuSO4.5H2O and FG-CuO. Weight gain, hematocrit, hemoglobin, plasma Cu, liver Cu, gall bladder (bile) Cu, and tendon lysine were assessed to determine whether dose-dependent Cu responses would occur. Gall bladder Cu concentration as well as total Cu content of the gall bladder were found to be linear functions of supplemental Cu intake. Common-intercept multiple linear regression (slope-ratio) of bile Cu concentration regressed on supplemental Cu intake indicated Cu bioavailability values (relative to the standard, AG-CuSO4.5H2O, set at 100%) of 97.9% for AG-Cu2O, 93.5% for FG-CuSO4.5H2O, and 112.9% for AG-CuCO3.Cu(OH)2. These values were not different (P > .05) from 100%. Relative bioavailability of Cu in AG-CuCl was 142.5%, which was different (P < .05) from the standard. Both AG-CuO and FG-CuO gave Cu bioavailability estimates not different (P > .05) from zero. The results indicate that when Cu levels are fed below the chick's requirement, bile Cu concentration is a sensitive indicator of net gut absorption of Cu.

Animal Feed↗
PubMed1993

Estimates of copper bioavailability from liver of different animal species and from feed ingredients derived from plants and animals.

Bile Cu accumulation in Cu-depleted chicks fed Cu concentrations between .56 and 1.56 mg/kg was used to estimate Cu bioavailability in several feed ingredients from both plant and animal sources, including liver from different species. Liver from slaughtered animals is rich in minerals and vitamins and is a significant source of Cu in canned pet foods. Liver from different species, however, was found to vary widely in Cu bioavailability (relative to CuSO4.5H2O, which was set at 100%). The bioavailability of Cu in freeze-dried (FD) chicken liver and poultry by-product meal was 116 and 97%, respectively, but that in FD pork liver was not different from zero. Relative bioavailability of Cu in FD beef, sheep, and turkey liver was 82, 113, and 83%, respectively. Copper in FD liver from the rat, a species that does not possess a gall bladder, was 21% bioavailable. Copper in the feed ingredients from plants: corn gluten meal, dehulled soybean meal, cottonseed meal, peanut hulls, and soy mill run was 48, 38, 41, 44, and 47% bioavailable, respectively. In addition, when the fibrous ingredients peanut hulls or soy mill run were added to the basal diet containing .5 mg Cu/kg from CuSO4.5H2O, Cu bioavailability in CuSO4.5H2O was reduced. The results of this study demonstrate a wide variation in Cu bioavailability among feed ingredients originating from plants and animals.

Analysis of Variance↗
PubMed1993

Nutritional evaluation of a copper-methionine complex for chicks.

Three chick experiments were conducted to evaluate a new Cu complex product, Cu-Met. Relative bioavailability of Cu was assessed with two bioassay systems, one employing bile Cu concentration as the criterion at Cu-deficient levels and another employing liver Cu concentration at Cu-excess levels. Relative bioavailability of Met was assessed separately. Common-intercept multiple linear regression (slope-ratio) of bile Cu concentration or liver Cu concentration regressed on supplemental Cu intake was used to assess Cu bioavailability relative to the standard, analytical-grade CuSO4.5H2O, which was set at 100%. In addition, Cu-Lys and CuCl (compounds previously evaluated by bile Cu concentration) were evaluated by the liver Cu accumulation method. Relative bioavailability of Cu in Cu-Met was estimated as 96% by the bile Cu assay and 88% by the liver Cu assay, which were not different (P > .05) from 100%. The liver Cu assay estimated that relative Cu bioavailabilities in Cu-Lys and CuCl of 114 and 145% (P < .05), respectively. These values were very close to those previously estimated by the bile Cu assay. Relative Met bioavailability of Cu-Met was 100% of the standard, i.e., feed-grade DL-Met.

Animal Feed↗
PubMed1992

Urinary excretion of taurine as a function of taurine intake: potential for estimating taurine bioavailability in the adult cat.

Urinary taurine excretion increases markedly when excess taurine is consumed. Experiments were designed to characterize this response in an attempt to develop an assay system for taurine bioavailability in common cat foods using an adult cat model. Initial studies investigated the time course of changes in urinary taurine excretion in response to alterations in taurine intake. The rate of urinary taurine excretion decreased rapidly when cats were switched from a casein diet supplemented with 0.2% crystalline taurine to a diet containing no supplemental taurine, reaching steady-state in 2 d. In contrast, urinary taurine excretion by cats switched from low to high taurine did not plateau until 6 to 7 d. Subsequently, cats (n = 18) were fed a casein diet containing graded levels of crystalline taurine (0, 0.025, 0.05, 0.10, 0.15 or 0.20%). After a 7-d adjustment period, urinary taurine excretion was quantified over a 5-d collection period and also by cystocentesis, and blood taurine levels were measured on d 6. Plasma taurine increased linearly (r = 0.88) as taurine intake increased, while whole-blood taurine increased asymptotically, reaching 95% of maximum concentration at a taurine intake of 93 mu mole/(kg body weight.d). The rate of urinary taurine excretion increased only slightly as taurine intakes increased to 96 mu mol/(kg body weight.d), but increased markedly (15-fold) thereafter. The same pattern was observed whether urinary taurine excretion was expressed as mu mole/(kg body weight.d) from total urine collection or as mu mole/g creatinine from cystocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗