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Biomedical subjects

C W Carlson

Publications and source records attributed to C W Carlson.

At least 19 recordsLinked to original sources
PubMed2001

Direct observation of localized parallel electric fields in a space plasma.

We report direct measurements of parallel electric fields related to particle acceleration in a collisionless space plasma. The electric field is that of a monotonic potential ramp localized to approximately 10 debye lengths along the magnetic field. Electrons accelerated by the parallel electric field are accompanied by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes.

Journal Article↗
PubMed2000

Effect of dietary phosphorus, calcium, and phytase on performance of growing turkeys.

Female and male turkeys were fed 110, 73, 52, and 30% of the NRC (1994) nonphytate P (NPP) requirement without and with 500 phytase units (FTU)/kg during 4 to 14 or 16 wk of age, respectively. At 110% P (control; also 110% of NRC Ca), phytase was without effect. At 73% of NPP (100% Ca), without phytase, performance was similar to the control; with phytase, performance was equivalent, and in some stages, superior to the control. At 52% of NPP (90% Ca), performance was inferior without phytase and was variably similar or poorer than the control with phytase. At 30% NPP without phytase, poults gained poorly and showed a high incidence of leg disorder at 8 wk when they were removed from experiment; poults gained better with 80% NRC Ca compared with 110%. At 30% NPP with phytase, turkeys performed remarkably well, although suboptimally, at 80 or 110% NRC Ca. Phytase at 400, 300, and 200 FTU/kg with increasing age periods performed as well as 500 FTU/kg with 73% of NRC NPP (100% Ca) and 52% NRC NPP (90% Ca). These lower phytase levels were not as sufficient as 500 FTU/kg with 30% of NRC NPP; this inadequacy was more severe with higher dietary calcium. Phytase was effective in reducing dietary P requirements of growing turkeys when the NPP levels were below NRC (1994) requirements.

6-Phytase↗
PubMed2000

Limiting amino acids after methionine and lysine with growing turkeys fed low-protein diets.

The effectiveness of Thr and other amino acids (AA) replacing CP in Met- and Lys-adequate diets of Large White male turkeys was studied from 6 wk to market age. Experiment (EXP) 1 examined efficacy of Thr and an AA grouping in corn-soybean (CS) diets containing 82.8 and 77.0% of NRC CP and in corn-soybean-canola-meat (CSCM) diets containing 85.2 and 79.4% of NRC (1984) CP. Experiment 2 compared AA responses in CSCM diets containing 100, 92.5, 85, and 77.5% of NRC (1994) CP. Compared with control CP, 1) 92.5% of NRC CP supported maximum BW, and supplemental Thr or Trp was without effect; 2) 82.8 to 85.2% of NRC CP resulted in reduced BW and breast meat yield (BMY), and supplemental Thr or Trp was ineffective in reversing this reduction, and 3) 77 to 79% of NRC CP resulted in depressed BW and BMY. Supplemental Thr provided a substantial positive BW but no BMY response, whereas a combination of Thr, Ile, Val, Arg, and Trp completely returned BW and partially returned BMY to that of the normal CP control. Turkeys on CS and CSCM assay diet series supported BW responses to CP and AA similarly. We concluded that in low-CP diets containing Met and Lys to requirement, supplemental Thr resulted in improved BW, whereas Thr, Ile, Val, Trp, and Arg returned BW, but not BMY, to normal CP control.

Amino Acids↗
PubMed2000

Identification of limiting amino acids in methionine- and lysine-supplemented low-protein diets for turkeys.

Large White male turkeys were fed 100, 85, 70, or 60% of NRC (1994) CP during 7 to 28 d (Experiment (EXP) 1), 8 to 12 wk (EXP 2), and 16 to 20 wk (EXP 3) of age. Diets contained corn, soybean, canola, and meat meals and were supplemented with Met and Lys to requirement. The influence of supplementary amino acids (AA) was studied at each protein level. Turkeys fed 85% CP gained BW similarly to those fed 100% of NRC CP (control) during each age range. Supplemental Thr, Val, and Ile during 7 to 28 d or 8 to 12 wk, or Thr during 16 to 20 wk, did not result in positive BW gain response. For turkeys fed 70% CP, BW gain was depressed compared with the normal-CP control in each period. During 7 to 28 d and 8 to 12 wk of age, the combination of Thr, Ile, Val, Arg, and Trp to 100% of NRC reversed the BW depression; here only Thr, Ile, and Val were essential components of the response. The BW depression during 16 to 20 wk was reversed by the combination of Thr, Ile, Val, and Trp. For turkeys fed 60% of CP, BW gain was severely depressed. The combination of Thr, Ile, Val, Trp, and Arg resulted in nearly complete BW recovery during each age.

Aging↗
PubMed1995

Replacing protein in corn-soybean turkey diets with methionine and lysine.

The extent to which dietary protein can be minimized by using Met and Lys supplements for market turkeys has been investigated in three experiments involving 2,750 birds. Large White (Nicholas) male turkey poults were fed corn-soybean meal diets of varying protein level to supply Lys from 80 to 120 of NRC (1984) from day-old to 18 wk of age. Performance with diets of 90% NRC Lys was equal to that with diets of higher Lys, provided that SAA were at 100% of NRC. Up to .2% Lys.HCl could be substituted into the 100 or 90% of NRC diets with no depression in performance, suggesting that the other essential amino acids were present in adequate amounts. When turkeys were fed diets of 85% of NRC (1984) Lys, maximum growth and breast meat yield were obtained with supplemental SAA at 100% during 0 to 18 wk of age and Lys at 100% during 12 to 18 wk of age. The requirements for other amino acids were supplied by diets formulated to provide 85% of the Lys requirement from protein. These values were for turkeys subjected to 18 C during final growout; they were not adequate in warmer temperatures.

Animal Feed↗
PubMed1988

Use of sunflower seeds in grower diets for pullets and subsequent performance as affected by aureomycin and pelleting.

In two experiments the effects of unhulled sunflower seeds (USFS) were evaluated at levels of 19 and 38% in corn-based diets for pullets between 10 and 19 wk of age. As an additional treatment a .09%-lysine monohydrochloride supplement was added to the 38% USFS-containing diet in Experiment 2. Isonitrogenous grower diets made up of corn and soybean meal or largely oats served as control diets. During the productive phase, layers were fed a high oats diet as mash (both experiments) or in pelleted form (Experiment 2). One half of the hens in each study were fed layer diets containing Aureomycin at 100 g per ton for 1 wk during each 28-day period to monitor the effect on egg production. Treatments during the laying phase were superimposed on the previous growing phase treatments. Pullets fed the 38% USFS diet in Experiment 1 were significantly lighter (P less than .01) at 19 wk of age and reached 50% egg production 2 days later than those on the control corn-soy diet. However, subsequent overall laying performance for 14 28-day periods was not significantly affected by the growing treatments. Neither growth nor laying performance was influenced by the treatments imposed during the rearing period of the second experiment. The two supplies of USFS varied considerably in crude fiber (14.6 vs 25.8%) and ether extract components (42.4 vs. 29.0%, respectively). The discrepancy in growth response to USFS of the two experiments was possibly related to the difference in the ether extract portions of the oil seeds. Egg production rate was significantly increased by Aureomycin only when the diet was pelleted.

Animals↗
PubMed1986

Effect of copper with three levels of sulfur containing amino acids in diets for turkeys.

The effects of adding copper or methionine to low-protein practical diets for turkeys were studied in two experiments involving an initial total of 2,496 day-old tom poults. In Experiment 1, 0 or 120 ppm copper were added to diets providing about 75, 85, or 100% of the National Research Council (NRC, 1977) requirements for sulfur amino acids (SAA) as supplemented by DL-methionine. Experiment 2 involved four levels of copper (0, 60, 120, and 240 ppm) added to diets containing three levels of SAA (75, 100, or 125%, NRC, 1977). Sixty ppm of copper improved 8-week body weight, while the effects of 120 and 240 ppm copper were growth depressing but not beyond 8 weeks of age. Increasing the methionine content of the diets to the 100% level for SAA (1977) consistently improved weight gain of younger birds. The improved body weight from methionine additions for the older turkeys (16 to 24 weeks) however, was significant only in Experiment 1. Copper did not influence the methionine requirement in these experiments.

Animals↗
PubMed1985

Effects of cellulase from Trichoderma viride on nutrient utilization by broilers.

Studies were conducted to evaluate the effects of cellulase from Trichoderma viride in a diet for broilers containing high levels of wheat bran. Broiler-type, mixed-sex chicks were fed from 3 to 8 weeks of age. Wheat bran was added at 0, 10, and 20% levels. A fourth group received the 20% wheat bran plus the cellulase enzyme added at the level of .008%. A portion of the chicks was used in a digestibility study with chromic oxide as an indicator. The summarized data showed that cellulose treatment had a significant effect on reducing feed consumption (P less than .01) and an apparent effect in improving feed-to-gain ratio. Cellulase supplementation significantly improved the digestibility of cell wall components (P less than .01). Calcium, phosphorus, iron, zinc, and copper associated with cell walls were solubilized by cellulase. Iron balance was negative in the groups without cellulase; however, iron, which is bound by the bran, apparently was made available for absorption by cellulase.

Animals↗
PubMed1980

Appearance of D-alloisoleucine in the blood plasma of laying hens.

Two strains of laying chickens were used to investigate the effects of amino acid additions, including D-alloisoleucine, to a low protein corn-soy diet on plasma free amino acids and egg albumen amino acid composition. Intake of .1% D-alloisoleucine with the L-form in the mixture resulted in appearance of this compound in the plasma but not in egg albumen. The concentration of plasma valine was significantly increased when the amino acid (.2% D-L) was added to the 10% protein diet. Threonine and arginine additions did not increase the concentration of the respective amino acid in the plasma significantly. The amino acid composition of egg albumen remained unaffected by dietary supplementation. Production data along with amino acid composition of egg albumen showed that the laying hen reduces production rather than altering amino acid composition of egg albumen protein in its response to reduced uptake. No apparent strain differences were noted.

Animal Feed↗
PubMed1979

Evidence for a high molecular weight factor(s) in serum which increases alkaline phosphatase specific activity in HeLa.

HeLa (substrain Ho) grown in serum free medium showed an increase in the specific activity of alkaline phosphatase when fetal calf serum (10%) was added to the medium (9.7 nmoles/sec/mg protein to 86.8). Under the same conditions, eight intracellular enzymes showed no increase in activity. Similar results were obtained using a different serum or medium, and with a second strain of HeLa (substrain ATC). For a given set of growth conditions, the effect of serum was dependent on its concentration and required one or more culture generations to develop. The type of isozyme expressed did not change. Neither zinc nor a total serum lipid extract would substitute for serum. The enzyme expressed by HeLaHo was not induced by prednisolone, while that in HeLaATC was. However, for cells grown in excess prednisolone without serum, the specific activity was 25% of that found for cells grown with prednisolone and serum. Cortexolone, an antagonist of prednisolone, was without effect for HeLaHo grown in A3 medium with or without serum. The serum factor had the following characteristics. It was not lost on dialysis, treatment with DNase and RNase, or removal of lipoproteins. It was reduced after heating by 65% and after treatment with Pronase by 82%. The data are interpreted to indicate the presence of a factor (s) in serum, probably a protein, which is involved in stimulating alkaline phosphatase specific activity.

Alkaline Phosphatase↗
PubMed1978

Copper salts for growth stimulation and alleviation of aortic rupture losses in turkeys.

Approximately 4000 Large White, day-old turkey poults were used in a series of eight experiments to study the effects of dietary copper supplementation. The hens were grown to 15 or 16 weeks and toms to 24 weeks of age. Either copper as the oxide or sulfate (hydrate) at 120 ppm stimulated growth up to 10% with a concurrent reduction in feed requirement. Levels of 60 ppm were not adequate, whereas 240 ppm were not toxic. There was a greater response to copper in the presence of 4-nitrophenylarsonic acid (4-nitro) or with low protein diets. In two of the eight studies copper enhanced aortic elastin content. Incidence of aortic rupture was greater in the presence of 4-nitro and was reduced by one-half through copper supplementation. Liver copper was not altered by 60 or 120 ppm Cu; 240 ppm caused a significant increase.

Animals↗
PubMed1976

Fungus-fermented soybeans benefit the life cycle of Japanese quail (Coturnix coturnix japonica).

Feeding quail chicks diets containing soybeans fermented with two cultures of Aspergilli (A. oryzae N.R.R.L. 451 and A. oryzae N.R.R.L. 506) resulted in significantly superior weight gains (p less than 0.05) through a 4-week growth period and confirmed previous observations made with identical cultures in broiler studies. Subsequent hen-day egg production and egg size were changed little by diets containing fermented soybeans. The numerical increases in fertility and hatchability were not significant. Progeny also responded to the fermented soybean diets, some carry-over effects were evident.

Animal Feed↗
PubMed1975

Involvement of cytosol proteins in oleate activation of rabbit liver fructose-1,6-diphosphatase.

Dialyzed rabbit liver cytosol was specifically freed of endogenous fructose-1,6-diphosphatase by immunoadsorption on a column of Sepharose-immobilized anti-fructose-1,6-diphosphatase. This material increased the specific activity of homogeneous enzyme to the maximal rate observed with EDTA and shifted the pH optimum from 8.4 to 7.4. With oleate or other fatty acids as activators, the hydrolysis of fructose-1,6-diphosphatase by enzyme, at neutral pH, showed nonlinear initial rates dropping to lower linear rates. Cytosol activator acted synergistically with oleate both to increase neutral enzyme activity and to maintain the high initial catalytic rates. After sucrose density centrifugation or gel filtration, the cytosol had no effect by itself, but still potentiated oleate activation. The factor was destroyed by treatment with subtilisin or trypsin, but all attempts to identify a unique protein component in cytosol were unsuccessful. The presence of Na dodecyl-SOJ, deoxycholate, or urea did not improve the resolution of the factor, but these compounds did lower the K50 for activation by cytosol. Since fatty acids are the only unique compounds which have been isolated from cytosol which activated fructose-1,6-diphosphatase, it appears that soluble proteins can act as natural carriers for the fatty acids. This was supported by the fact that both dialyzed rabbit alpha-globulins and muscle phosphofructokinase also acted synergistically with oleate in a manner similar to cytosol. Phosphatidic acid and phosphatidylserine activated fructose-1,6-diphosphatase, and their action was synergistic with oleate. Glutathione (1 mM) activated the enzyme 5-fold at pH 7.3 and its effects were additive with oleate and cytosol or alpha-globulins.

Albumins↗