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Biomedical subjects

C R Douglas

Publications and source records attributed to C R Douglas.

15 recordsLinked to original sources
PubMed1990

An evaluation of a stepdown amino-acid feeding program for commercial pullets to 20 weeks of age.

Two experiments were conducted to study the use of a feeding program based on dietary amino-acid levels for commercial egg-production replacement pullets from 8 to 20 wk of age. HyLine W-36 pullets were used in Experiment 1; and HiSex White pullets were used in Experiment 2. All pullets were fed a starter diet calculated to contain 21% CP for the first 8 wk of age. From 8 to 20 wk of age, they were fed 10 series of diets calculated to provide various levels of TSAA, lysine (Lys), tryptophan (Trp), and arginine (Arg) at various ages. The levels of each of these amino acids were lowered every 2 weeks. The following levels of amino acids, based on calculated values suggested for corn and soybean meal, were found to be adequate from 8 to 20 wk, with linear reductions at biweekly intervals: .54 to .42% TSAA (.28 to .21% methionine), .64 to .48% lysine, .18 to .14% tryptophan, and .96 to .78% arginine.

Amino Acids↗
PubMed1989

Performance of Leghorn type hens fed two levels of energy and a synthetic estrogen during the growing period.

Feeding of an estrogen, dienestrol diacetate, at 352 mg/kg of diet to December-hatched White Leghorn type pullets, from 16 to 20 wk of age, caused onset of production to be delayed approximately 3 wk. The dietary dienestrol diacetate also resulted in increased body weights at 30 and 46 wk in one experiment. Hens receiving the estrogen laid significantly (P less than .05) heavier but fewer eggs during most of the production year than did those fed diets without the estrogenic compound. The addition of 2.2% fat to diets of pullets from 0 to 20 wk of age failed to influence their performance in the layer house.

Animal Feed↗
PubMed1987

Increased susceptibility of mice to MHV 3 infection induced by hypercholesterolemic diet: impairment of Kupffer cell function.

Nutritionally induced hypercholesterolemia in A/J mice causes susceptibility to Mouse Hepatitis type 3 (MHV 3), whereas normal A/J mice are fully resistant. A/J mice fed with a hypercholesterolemic diet for 15 to 60 days develop 5 to 7 days after MHV 3 infection an acute hepatitis which led to high levels of mortality. A direct relationship was found between the high levels of plasma and hepatic cholesterol and the mortality. In attempting to define the dietary-induced physiological changes which led to the loss of resistance, the Kupffer cells were shown to exhibit an impairment of functions in their ability to become activated by LPS in order to take up C3-coated IgM opsonized sheep red blood cells, C3(IgM)SRBC, or 3H-thymidine Escherichia coli, and the susceptibility to interferon (IFN) for the induction of an antiviral state. Peritoneal macrophages which were studied in comparison with the Kupffer cells showed no impaired functions. The findings presented here indicate an inhibition of host resistance, by nutritional hypercholesterolemia, of A/J mice to MHV 3 infection and that, at least one site of impairment occurs specifically at the stage of Kupffer cells function.

Animals↗
PubMed1986

Effect of mast cell stimulators or inhibitors on plasma lipids and aortic content of lipids, hexosamine and hydroxyproline in rats.

Twenty-one-day-old rats were treated with mast cell stimulators or inhibitors. Mast cell inhibition produced decrease of total cholesterol in plasma and aorta, while the stimulation led to an increase. Both stimulation and inhibition produced increased levels of plasma and aorta triglycerides, and decrease of aorta content of hexosamine, hydroxyproline and total protein; these same effects could be due to different release of specific mast cell mediators.

Animals↗
PubMed1986

Effects of mast cell inhibition on plasma and aortic content of lipids, hexosamine, and hydroxyproline in rats. Role of thyroid gland.

Twenty-one-day-old rats were treated with mast cell inhibitors for four weeks. Some of the rats were thyroidectomized in the beginning of the experiment. Mast cell impairment decreased plasma cholesterol and increased plasma triglyceride levels; in aorta, there was a decrease in total protein, hexosamine and hydroxyproline levels, while triglyceride concentration increased and total cholesterol did not change. In thyroidectomized rats, mast cell impairment led to decreased plasma cholesterol and aortic triglyceride content, increased aortic hexosamine and hydroxyproline levels and did not change plasma triglycerides, aortic total cholesterol and total protein content. It was concluded that some effects of mast cell inhibition on arterial wall metabolism are mediated through the thyroid gland.

Animals↗
PubMed1986

Biochemical observations on rat aorta: interaction of dietary protein and cholesterol.

1. The effect of cholesterol feeding during and after a period of protein malnutrition lasting 4 weeks was examined in the rat. Indices measured were plasma total cholesterol, triglycerides and protein levels, and aorta total cholesterol, triglycerides, hexosamine and hydroxyproline concentrations. 2. In both plasma and aorta, total cholesterol and triglycerides levels were higher in the low-protein diet group than in the standard-protein diet group, when cholesterol was supplied in both diets. 3. During the malnutrition period, cholesterol feeding led to a greater decrease in plasma protein than that promoted by the low-protein diet without cholesterol, while aorta hexosamine levels decreased to a lesser extent. 4. Cholesterol feeding with a standard-protein diet promoted a slight and temporary increase in aorta hydroxyproline levels, while a decrease in aorta hexosamine concentration was observed. Cholesterol feeding with the low-protein diet, on the other hand, also promoted a decrease in aorta hexosamine levels but to a lesser extent. 5. During the recovery period, cholesterol feeding impaired the return of plasma protein, aorta hexosamine and lipid levels to that of the control values. 6. These findings demonstrate that cholesterol feeding promotes different changes in aorta and plasma, depending on whether or not protein is supplied by the diet in adequate amounts. This point could be important in relation to the development of atherosclerosis during recovery from a period of malnutrition.

Animals↗
PubMed1986

Phosphorus requirement of commercial Leghorn pullets from 8 to 20 weeks.

Hisex White pullets, hatched in November, were used to study the influence of the amount of dietary phosphorus in practical grower diets during the 8 to 20-week growing period. Measurement were made on 20-week body weight, bone ash, and layer house performance. All chicks were fed a 21% protein starter diet through 8 weeks at which time they were randomized into eight treatment groups. Grower diets were changed at 8, 12, and 16 weeks at which time different dietary phosphorus percents were used. Percents of total phosphorus used were .60, .55, .50, .45, and .32 for 8 to 12 weeks and .31 for 13 to 20 weeks. Lowering the phosphorus to .32% at 8 weeks or .31% at 12 weeks significantly reduced 20-week body weight. Lowering total phosphorus to .31% at 16 weeks did not significantly affect 20-week body weight. Bone ash measured at 20 weeks was not significantly affected by feeding less phosphorus. Laying house mortality, egg production, egg weight, and egg specific gravity were not influenced by lowering phosphorus in grower diets.

Animals↗
PubMed1985

A step-down protein program for commercial pullets.

Three experiments were conducted to evaluate the protein requirement of commercial egg production pullets from 8 to 20 weeks of age. Hyline W-36 pullets were used in Experiments 1 and 3, and Hisex White pullets were used in Experiment 2. They were fed a 20% protein diet for the first 8 weeks. In Experiment 1, a diet containing 14% protein did not result in body weight at 16 weeks equal to that obtained from feeding a diet containing 17% protein. In Experiments 2 and 3, body weights of pullets fed a diet containing 17% protein from 8 to 10 weeks followed by 1% protein reduction biweekly thereafter (12% from 18 to 20 weeks) was equal to that obtained by feeding 18% for the entire period. Performance in the laying house for four 28-day periods was equal for the two treatment groups. Feeding diets with suboptimal protein from 8 to either 12 or 14 weeks of age resulted in reduced body weight. However, when 14% protein was fed for the remainder of the growing period, body weight was restored.

Age Factors↗
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↗
PubMed1976

Response of laying hens to a low salt diet.

Two experiments were conducted with commercial Leghorn-type hens in advance state of production (16 months of age) to determine response to a 16% protein, corn-soy diet with no added salt. There was an immediate and significant decline in feed consumption. Body weight decreased significantly. After 14 days, there were no ova in the rapidly maturing stage. The ovary may have been reduced in size but apparently was not regressed. Egg specific gravity was significantly reduced but egg weight was unaffected. Egg production dropped to 0% in 17-21 days. On the return of 0.25% salt to the diet, recovery as measured by production rate was initiated immediately with production reaching 79% in 16 days compared to a pre-experimental production of 68%.

Animals↗
PubMed1975

Reduction of aflatoxin effects of quail.

A natural occuring outbreak of aflatoxicosis was observed in Bobwhite quail chicks while on a brooding experiment. A slight reduction in effects was noted for birds which received Tylan in the water from 0-3 days and Terramycin from 0-35 days of age. No symptoms of aflatoxicosis were observed in birds which received a product (FloxAid) containing two antibiotics and eight vitamins from 0-14 days. It is postulated that the primary mode of protection was via the water soluble vitamin D content of the product with possibly some protection from vitamins A, E and K.

Aflatoxins↗
PubMed1975

Debeaking method for Bobwhite quail.

Four experiments were conducted to determine the suitability of various debeaking procedures for Bobwhite quail at hatching or at one week of age. Two experiments were conducted using a "precision" type debeaking method with the following treatments: control; debeaked at hatching with debeaker guide plate holes of 2.38 or 2.78 mm; debeaked at seven days of age using guide plate holes of 2.38, 2.78 or 3.18 mm. Two experiments tested a "touch-burn" method at hatching with the following treatments: control; burned 1/4 distance to nares; and burned 1/2 distance to nares. The "precision" type methods at hatching or seven days of aged reduced mortality from cannibalism; however, these methods were found to be relatively slow and difficult, and the birds lacked uniformity in beak and body size at five weeks of age. Burning 1/2 distance to nares was too severe, causing a reduction in body weight and poor feed efficiency. Burning 1/4 distanct to nares gave the most favorable results: growth and feed efficiency as good or better than controls, uniform birds and decreased cannibalism.

Animals↗