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Biomedical subjects

H R Wilson

Publications and source records attributed to H R Wilson.

At least 163 records · Page 9Linked to original sources
PubMed1980

Protein and sulfur amino acid requirements of broiler breeder hens.

Two experiments were conducted with Cobb color-sexed broiler breeder hens to determine their protein and sulfur amino acid requirement. A daily intake between 400 and 478 mg of methionine and between 722 and 839 mg of total sulfur amino acids was necessary for maximum egg production, the latter in a diet of 13.07% protein. Slightly lower levels supported maximum body weights. Hens laying at the highest rate consumed 23.4 g of protein per day.

Amino Acids, Sulfur↗
PubMed1979

Further evidence for four mechanisms mediating vision at threshold: sensitivities to complex gratings and aperiodic stimuli.

It is now generally accepted that several mechanisms mediate contrast detection at threshold. Many attempts to measure the bandwidths of these mechanisms using subthreshold summation have yielded estimates suggesting very narrow frequency tuning. We have measured thresholds for three classes of stimuli: gratings containing two sinusoidal components, sums of "difference of Gaussian" (DOG) patterns, and square waves. The results of the subthreshold summation experiments with gratings are consistent with those of other studies. All of these thresholds can be predicted by a model requiring only four center-surround-type mechanisms at each retinal locus. These mechanisms have a full bandwidth at a half-height of about 1.75 octaves. Quantitative prediction of sensitivities depends critically upon spatial probability summation. It is this spatial nonlinearity that yields these somewhat conterintuitive results. The much narrower bandwidths inferred by others are due to the assumption of linearity used in their analyses.

Computers↗
PubMed1979

Response of hens to various dietary levels of tannic acid.

One-hundred-twenty Babcock B-300 ehns, 17 months of age, were placed one bird per cage with six replicates of five birds each per treatment. Four levels (0, 1, 2, and 4%) of technical grade tannic acid were added to a standard corn-soy layer diet. With the exception of feed comsumption during the second and third week, there were no significant differences for feed consumption, egg production, feed efficiency, fertility, or hatchability amond the control birds and those receiving tannic acid at the 1% level. The addition of tannic acid at levels of 2 and 4% resulted in significantly decreased feed consumption and egg production during the six-week experimental period. Fertility and hatchability were not significantly affected by dietary tannic acid.

Animals↗
PubMed1979

Hatchability of bobwhite quail eggs incubated in various temperature combinations.

Five experiments were conducted to compare the effects of various incubation temperature combinations on the hatchability of Bobwhite quail eggs. A starting incubation temperature of 40.6 C resulted in numerically lower hatchability. Incubation at 37.5 C resulted in a greater number of pipped, unhatched eggs, and a later, less uniform hatch. Temperatures during the hatching period (22 to 25 days of incubation) of 36.9 C and 38.1 C resulted in lower hatchability than the hatching temperature of 37.5 C.

Animals↗
PubMed1978

Human flicker sensitivity: two stages of retinal diffusion.

A well-known solution of the diffusion equation gives an exponential square-root function as the frequency response for a one-dimensional diffusion or transmission process. When two or more such processes are cascaded, the result is still an exponential square-root characteristic, but with a longer time constant. This seems to explain why flicker thresholds obey the Kelly-Veringa diffusion model at high frequencies, even though the psychophysically inferred diffusion process is much slower than the first stage of visual transduction measured by, for example, late receptor potentials. Two such stages in tandem are sufficient to account for the psychophysical data, because the psychophysical time constant is proportional to the square of the number of stages involved. In addition, the nonlinear behavior of flicker thresholds under intense light adaptation can be explained if the loss factor in the first stage is proportional to the amount of the photopigment bleached. Apparently the flicker thresholds are governed by first- and second-order retinal neurons.

Adaptation, Physiological↗
PubMed1978

The relationship of production status to serum calcium and phosphorus in hens.

The effect of production status on the serum levels of calcium and phosphorous of laying hens was examined. Commercial-type White Leghorn hens, 66 weeks of age, were selected on the basis of whether or not they had laid an egg each day during a two-day period. A five ml. blood sample was collected via anterior heart puncture from each of the selected hens and subjected to serum calcium and phosphorus analyses. Serum phosphorus varied significantly in relation to whether or not a bird laid an egg the day before and/or the day of blood collection. Except for birds which were reproductively inactive, serum calcium was less affected by production status than was serum phosphorus. It was hypothesized that the variations were related to the physiological changes in shell calcification activity, bone resorption and remineralization, intestinal absorption of minerals and muscular activity. It was suggested from the results that birds selected for serum mineral analyses should be of similar production status.

Animals↗
PubMed1978

The response of Bobwhite quail chicks to dietary ammonium and an antibiotic-vitamin supplement when fed B1 aflatoxin.

Dietary ammonium phosphate and a water soluble antibiotic-vitamin supplement were tested as possible means of preventing or minimizing the effects of aflatoxin in the diet of Bobwhite quail chicks. Aflatoxin (B1) was added to the diet at levels of 0, 0.4 and .8 ppm in Experiment 1 and 0, .8 and 1.2 ppm in Experiment 2. In addition, ammonium phosphate was included in the diet at levels of 0 or 1.46% and an antibiotic-vitamin supplement was added to the drinking water at 0 or 600 mg/liter. All treatments were given from 1 to 32 days of age in Experiment 1 and 1 to 28 days of age in Experiment 2. The addition of aflatoxin to the diet resulted in decreased body weight, feed consumption and percent tibia ash, increased mortality and increased feed required per unit of body weight. The addition of ammonia to the diet in the form of monoammonium phosphate did not alleviate the effects of aflatoxin. Water supplementation with an antibiotic-vitamin mixture improved weight and feed efficiency and decreased mortality of chicks receiving aflatoxin.

Aflatoxins↗
PubMed1977

Cyclic changes in serum phosphorus of laying hens.

Three trials were conducted to measure changes in the serum phosphorus level of laying hens over a 24-hour period. Sixty-three-week-old hens were selected for blood sampling according to the criteria that: 1. they laid an egg the day prior to and the day of blood collection and 2. the oviposition time on both days was 10 a.m. +/- 2 hours. Blood samples were obtained via heart puncture. Serum was collected by centrifugation, deproteinized and analyzed colorimetrically for phosphorus content. Sampling times were as follows: Trial 1--6 p.m., 12 midnight, 6 a.m. and 12 noon; Trial 2--6 a.m., 8 a.m., 10 a.m., 12 noon, 2 p.m., 4 p.m. and 6 p.m.; Trial 3--12 midnight, 4 a.m. and 7 a.m. Hens used in this study received natural and/or artifical light from 4:30 a.m. to 7:30 p.m. each day. Results indicated that serum phosphorus reached a peak of 6.08 mg.% at 7 a.m. At 8 a.m., the phosphorus level dropped to 4.88 mg.% and remained within 0.08 mg.% of this value until 12 noon. From 2 p.m. to 6 a.m. it gradually increased from 5.29 mg9% to 5.80 mg.%. Observed changes in serum phosphorus over time are related to changes in shell calcification, bone resorption and remineralization, and renal clearance.

Animals↗
PubMed1977

Feed consumption and protein efficiency by Bobwhite quail in response to dietary energy levels.

Two experiments were conducted to determine if Bobwhite quail chicks would adjust feed consumption according to energy intake from hatching to five weeks of age. Three starter diets, which were calculated to contain 2850, 3010 and 3170 Kcal. M.E./Kg., were fed throughout the five-week experiments. As energy was increased, the protein level was increased proportionally. Each treatment group consisted of four replicate pens containing 125 chicks each. Body weight at two and five weeks of age was not affected by treatment, except for a reduction at two weeks for birds on the 3170 Kcal./Kg. diet. There were no significant treatment effects on mortality. The feed consumed/bird/day decreased as dietary energy was increased. The calculated energy consumption/bird/day was 15.44, 15.31 and 14.79 Kcal., respectively, for the 2850, 3010 and 3170 Kcal. M.E./Kg diets during the five-week period. The energy and protein consumption per gram of body weight was slightly reduced at the high energy level indicating a more efficient use of energy and protein of the high energy diet. These data indicate that the Bobwhite quail adjusts feed intake according to the energy content of the diet.

Animal Feed↗
PubMed1977

Serum calcium and phosphorus levels in hens relative to the time of oviposition.

An experiment was conducted to examine the serum calcium and phosphorus level of hens in relation to time of oviposition. Sixty-eight-week-old hens were selected for blood sampling according to the criteria that: 1. they laid an egg the day prior to and the day of blood collection, and 2. the oviposition time on both days was 10 a.m. +/- 2 hours. Samples were taken at hourly intervals, from five hours before through two hours after, and again at four hours after oviposition and were analyzed for serum calcium and phosphorus. All birds received natural and/or artificial light from 4:30 a.m. to 7:30 p.m. each day. Results indicated that serum phosphorus increased from 6.46 to 6.82 mg.% during the period from five to three hours prior to oviposition. Between three and two hours before time of lay, it dropped to a level of 4.75 mg.%, where it remained (+/- 0.35 mg.%) for the remainder of the test period. Serum calcium did not change appreciably during the 10-hour test period. It was hypothesized that the serum phosphorus cycle of the hens is composed of two segments of approximately six and 18 hours duration. The segments were delineated on the basis of activities of bone resoprtion and remineralization and egg shell formation.

Animals↗