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Biomedical subjects

E C Naber

Publications and source records attributed to E C Naber.

At least 19 recordsLinked to original sources
PubMed1993

Vitamin profiles of eggs as indicators of nutritional status in the laying hen: vitamin A study.

Laying hens were fed deficient diets, unsupplemented or supplemented with one, two, or four times the National Research Council requirement level of vitamin A for 27 wk. Vitamin A levels of egg yolk from hens fed the unsupplemented diet slowly declined but levels of vitamin A stabilized at 12 wk in the supplemented groups and were related to dietary level. Egg production of hens fed the unsupplemented diet declined significantly after 12 wk and egg yolk levels continued to decline to Week 27. Hatchability of eggs laid by the unsupplemented hens was significantly lower at Weeks 25 and 26 than hatchability for those hens receiving dietary vitamin A. Hen weight, egg weight, and shell thickness were not consistently changed by treatment. In a second experiment, hens were fed a diet with and without 9,000 IU vitamin A/kg of diet. With birds receiving the supplemented diet, egg yolk vitamin A levels were stable after 13 wk, whereas egg yolk levels from unsupplemented hens declined slowly. Egg production with the unsupplemented diet was significantly reduced after 16 wk but the magnitude of the reduction was less than that in the first experiment, although egg vitamin A levels were as low as those in the first experiment. Hatchability of eggs during Weeks 25 to 28 was greatly reduced. Egg weight, albumen score, and chick weight were not consistently altered by vitamin A status. Because declines in egg yolk vitamin A do not precede declines in egg production they are not useful to predict future vitamin A deficiency in laying hens.

Animals↗
PubMed1993

Vitamin profiles of eggs as indicators of nutritional status in the laying hen: riboflavin study.

Two experiments determined the effect of dietary riboflavin supplementation on egg yolk and albumen riboflavin concentrations, egg production, egg weight, shell thickness, hen weight, hatchability, incidence of clubbed down, and incidence of hemorrhagic embryos. In the first experiment, hens were fed rations containing 1.55, 2.20, 4.40, and 8.80 mg of riboflavin/kg of diet for 27 wk. Significant (P < .05) depressions in both yolk and albumen riboflavin concentrations were noted at the two lower riboflavin levels after 1 wk. Egg production, egg weight, hatchability, and hen weight were all significantly depressed by the two lower riboflavin levels later in the experiment when compared with the two higher levels. Results indicate that egg riboflavin concentrations are related to important production parameters that may be used to predict future dietary riboflavin inadequacies. In the second experiment, hens were fed either an unsupplemented diet or a riboflavin-adequate diet. Measurements of egg albumen riboflavin content, egg production, hatchability, and embryo abnormalities were made twice each week. Results showed depressed albumen riboflavin concentrations and hatchability and increased incidence of hemorrhagic embryos and clubbed down without changes in egg production during the 4- to 7-day period following feeding of the unsupplemented diet. These results show that low albumen riboflavin content immediately affect hatchability and embryonic development. The estimated minimum critical albumen riboflavin concentrations needed to support maximum reproductive function are between 1.9 and 2.9 micrograms of riboflavin/g of egg albumen. These critical values might be used to evaluate riboflavin status of laying and breeding flocks.

Animal Feed↗
PubMed1992

The effects of heat, water, acid, and alkali treatment of tomato cannery wastes on growth, metabolizable energy value, and nitrogen utilization of broiler chicks.

Two experiments were conducted to determine the effects of heat, water, acid, and alkali treatment of tomato pomace on gain, feed to gain ratio, nitrogen utilization, and ME of diets for broiler chicks. In Experiment 1, both treated and untreated tomato pomace was included in broiler diets at a 10 or 20% level. Results indicated that the level or antinutritional factors present in untreated tomato cannery waste did not appreciably depress any measured production parameter. Hence, it appeared that untreated tomato cannery wastes might be used as a feed ingredient in low-energy poultry diets (broiler breeder and laying hen recycling rations), ruminant diets, and as a protein source in regions of the world where such feed ingredients are scarce. The second experiment was designed to test the effect of alkali concentration and treatment time of tomato pomace on the performance of broiler chicks. Alkali treatment of tomato cannery wastes increased gain and decreased feed to gain ratios of broiler chicks over those of untreated tomato waste controls. Results indicated that the increased gain and decreased feed to gain ratios of the chicks were due in part to the acid neutralization phase of the alkali treatment. Alkali treatment apparently affects the tomato cannery wastes almost instantaneously, as differences among actual treatment times and concentrations were small. However, only the highest alkali treatment increased the pH of the tomato cannery waste above 7, suggesting that a true alkali treatment might cause additional improvements in gain and feed to gain ratio when fed to broiler chicks.

Animal Feed↗
PubMed1992

Vitamin profiles of eggs as indicators of nutritional status in the laying hen: vitamin B12 study.

Hens of a type used for egg production were fed a corn and soybean meal diet supplemented with no vitamin B12 or with vitamin B12 levels to provide one, two, or four times the National Research Council (1984) breeding hen requirement of 4 micrograms/kg diet for 27 wk. All hens were placed on a recovery diet containing one and one-half times the requirement level of vitamin B12 from Weeks 27 through 30. Egg yolk vitamin B12 concentrations were determined frequently by radioisotope dilution analysis. Egg production records were kept continuously, and eggshell thickness, egg weight, hatchability of eggs, and hen body weights were measured at selected times. Although egg yolk vitamin B12 concentrations were high at the outset, they decreased markedly in 2 wk from hens fed the two lowest dietary levels. After 12 wk on the diets, egg concentrations of vitamin B12 stabilized and were proportional to the amount of vitamin added to the diet. Egg concentrations of vitamin B12 between 1.3 and 2.6 micrograms/100 g yolk appeared to be needed to support maximum hatchability and egg weight. Egg production was reduced after 12 wk on the diets in the hens fed the two lowest vitamin B12 levels. As vitamin B12 level increased, shell thickness decreased and egg weight, hen weight, and hatchability increased. Maximum egg production, egg weight, hen weight, and hatchability were obtained when the diet contained 8.0 micrograms/kg of vitamin B12. Egg yolk vitamin B12 concentrations respond rapidly to dietary changes in the level of this vitamin and are indicative of the vitamin B12 status of the hen.

Animals↗
PubMed1989

Patterns of lipogenesis in laying hens fed a high fat diet containing safflower oil.

Lipogenesis by liver and ovarian tissue in vitro, incorporation of lipids synthesized de novo into the egg yolk in ovo, and the fatty acid composition of liver and yolk triglycerides were studied in laying hens fed a low fat control diet or 30% safflower oil diet for 3 wk. The study was conducted to determine if reduced triglyceride synthesis and the fatty acid composition of dietary fat could account for the changes in the fatty acid composition of liver and egg yolk triglyceride from safflower oil feeding. Triglyceride synthesis was reduced by safflower oil feeding. Relative distribution of labeled carbon into liver triglycerides and phospholipids was also reduced. In vivo incorporation of labeled carbon from [1-14C]acetate into egg yolk triglycerides and phospholipids closely paralleled that in liver slices, suggesting that the liver controls the pattern of lipid incorporation into yolk. The fatty acid composition of liver and yolk triglycerides was markedly altered by safflower oil feeding. The changes in fatty acid composition of yolk triglycerides could not be accounted for by the reduction in triglyceride synthesis and the fatty acid composition of safflower oil.

Acetates↗
PubMed1989

Prediction of carcass composition of turkeys by blood lipids.

Prediction of percentages of carcass fat or abdominal fat pad by blood plasma concentrations of triacylglycerides (TG) and nonesterified fatty acids (NEFA) was examined in growing turkeys fed diets low in fat. Both TG and NEFA were determined under ad libitum feeding and after overnight fasting conditions. Abdominal fat and blood plasma TG were significantly correlated (P less than or equal to .01). Males and females did not differ in NEFA concentration under ad libitum feeding, but males had higher concentrations of NEFA after overnight fasting (P less than or equal to .05). The concentration of NEFA was not correlated with abdominal fat (P greater than .05).

Abdomen↗
PubMed1988

Reproductive performance of hens fed field beans and potential relationships to vicine metabolism.

Field beans (faba beans, broad beans, horse beans, ackerbohnen, Vicia faba L.) depress weight of eggs when fed to laying hens. Vicine isolated from field beans has been shown to depress egg weight and hatchability when fed in large amounts. The present study was undertaken to determine the effect of using three varieties of field beans, varying in tannin and total vicines content, at 20% in breeder diets on reproductive performance of hens and associated vicine transfer from the diet to the egg. Data on egg production, feed consumption, egg weight, body weight, egg quality, hatchability, and hen blood chemistry were obtained. Direct spectrophotometric and high pressure liquid chromatographic (HPLC) analyses of field beans, egg albumen, and egg yolk were conducted. Performance of the hens was excellent on all production characteristics except that there was a nonsignificant reduction in egg weight, a significant reduction in egg shell thickness for hens fed all three types of field beans, and a highly significant reduction in hatchability of eggs from hens fed one but not the other two sources of field beans. The hatchability effect was not correlated with vicine or tannin content of the field beans and only traces of vicine were transferred to the egg by the hen from the diet. Although larger amounts of vicine depressed hatchability when injected into fertile eggs, the trace amounts found in eggs from feeding field beans did not account for the reduction in hatchability observed in this study. It is possible that the hydrolysis product of vicine, divicine or the analogous product from convicine, isouramil, or both, may be involved in toxicity, because these substances are known to be the cause of a hemolytic anemia in some humans that suffer from favism due to consumption of field beans.

Animal Feed↗
PubMed1987

Effects of pure capsaicinoids (capsaicin and dihydrocapsaicin) on plasma lipid and lipoprotein concentrations of turkey poults.

The effects of capsaicin and dihydrocapsaicin on blood lipid and lipoprotein concentrations were determined in two groups of turkeys. The first group was maintained on a cholesterol-free diet, while the second received a diet supplemented with 0.2% cholesterol. Daily administration of capsaicinoids occurred at a dose of 4 mg per animal. Neither drug had an effect on serum triglyceride concentrations in the animals receiving the cholesterol-free diet. However, total cholesterol, LDL-cholesterol and HDL-cholesterol concentrations were increased significantly, while VLDL cholesterol concentrations were decreased significantly by both drugs relative to controls. In the cholesterol-fed group triglycerides, total cholesterol and LDL-cholesterol decreased significantly with dihydrocapsaicin treatment. Both compounds reduced VLDL-cholesterol and increased HDL-cholesterol in the cholesterol-fed animals. Dihydrocapsaicin had a greater efficacy in producing beneficial anti-hyperlipidemic effects in the cholesterol-fed animals.

Administration, Oral↗
PubMed1986

Effect of dietary 7-ketocholesterol, pure, or oxidized cholesterol on hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, energy balance, egg cholesterol concentration, and 14C-acetate incorporation into yolk lipids of laying hens.

Experiments were conducted to study the effect of 7-ketocholesterol (7-k) in the presence or absence of pure cholesterol (PCH) or oxidized cholesterol (OCH) in diets of laying hens on reproductive performance and several parameters of cholesterol metabolism. In the first experiment, cholesterol synthesis and transport was examined by the in ovo incorporation of 14C-acetate into yolk triglycerides and cholesterol. Energy balances were also conducted. In the second experiment, hepatic 3 hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity was measured in vitro to evaluate potential cholesterol synthesis. In both experiments, reproductive performance and egg yolk cholesterol concentration were measured. Dietary PCH or OCH (.5%) significantly reduced relative acetate incorporation into yolk cholesterol, while 7-k (.025%) had no effect on carbon flow from acetate into egg cholesterol. While 7-k alone did not alter total yolk cholesterol concentration, it moderated the effect of PCH or OCH on increasing yolk cholesterol concentration. No consistent effects of dietary sterols on reproductive performance or energy balance were observed. Hepatic HMG CoA reductase activity was dramatically suppressed by feeding PCH or OCH and moderately suppressed by 7-k. In combination with PCH or OCH, 7-k did not further depress enzyme activity. The observations that 7-k alone depressed hepatic HMG-CoA reductase activity, without changing relative acetate incorporation into yolk cholesterol while limiting cholesterol deposition in egg yolk from PCH or OCH, is interpreted to mean that 7-k may stimulate sterol transport and excretion while limiting cholesterol synthesis.

Acetates↗
PubMed1985

Effect of cholesterol oxidation products on cholesterol metabolism in the laying hen.

Two experiments were conducted to determine the effect of purified cholesterol and oxidized cholesterol in the diet of the laying hen on egg production characteristics, in vitro - in ovo utilization of acetate for cholesterol biosynthesis, and the activity of hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase, the rate-limiting enzyme in biosynthesis of cholesterol. Previous work has demonstrated inhibition of cholesterol synthesis by cholesterol oxides in tissue culture cells but not in hepatic tissues of animals through dietary administration. Feeding .5% of either purified or oxidized cholesterol had no effect on egg production, egg weight, body weight, or diet consumption. In both experiments egg yolk cholesterol was significantly increased by both cholesterol sources, but eggs from hens fed oxidized cholesterol had lower cholesterol contents than those from hens fed purified cholesterol. Relative utilization of acetate for cholesterol biosynthesis was significantly reduced by feeding both cholesterol sources. Hepatic enzyme activity measured by production of mevalonic acid was significantly inhibited by feeding purified cholesterol. A further significant reduction in enzyme activity was observed when oxidized cholesterol was fed, indicating that dietary cholesterol oxides are much more potent than purified cholesterol in limiting the activity of the enzyme.

Acetates↗
PubMed1984

Relationship between dietary fiber and nutrient density and its effect on energy balance, egg yolk cholesterol and hen performance.

Two experiments were conducted to determine the effect of dietary fiber in rations of varying nutrient density on egg yolk cholesterol, energy balance and reproductive efficiency of laying hens. Initially, four diets arranged in a Latin square design were tested: low, medium and high nutrient density diets and a control diet. The energy-to-protein ratio was 171.8 kcal/% protein for all diets. Significant differences (P less than 0.01) were observed between diets for feed intake, feed efficiency and fecal output of the hens. Dietary differences in yolk cholesterol, egg production, egg weight, body weight change and energy balance were not significant, and hence unrelated to dietary fiber level. A significant negative correlation (P less than 0.01) was found between yolk cholesterol and egg production (r = -0.45) or egg energy output (r = -0.38). In addition, yolk cholesterol was positively correlated with body weight change (r = 0.23, P less than 0.01). In the second experiment, the possible relationship between level of feed intake, body weight change and yolk cholesterol was further investigated. Yolk cholesterol tended to increase when the laying pullets consumed more than 387 kcal ME/day or gained more than 100 g in body weight. When the energy intake was less than 340 kcal ME/day or the birds lost body weight, an increase in yolk cholesterol also was noted but was inversely related to feed intake or body weight change.

Analysis of Variance↗
PubMed1984

Effectiveness of low sodium diets for recycling of egg production type hens.

Egg type hens were recycled by the use of low sodium diet treatments compared to a conventional forced-molt procedure and an unrecycled control. Use of a low sodium diet containing .02 to .06% sodium for 6 weeks with reduction in daily photoperiod resulted in improvements in egg production, egg specific gravity, and albumen thickness similar to those of a forced-molt group in three separate experiments. Egg production was increased 11 to 13%, egg specific gravity was increased by .002 to .004, and albumen thickness was increased by 2 to 8 Haugh units over the 32-week posttreatment period for both treatments. Hens fed the low sodium diet for 3.5 or 4 weeks did not respond as favorably as hens fed this diet for 6 weeks. Eight weeks on the low sodium diet did not further improve performance. Results comparable to the forced-molt procedure were achieved with a decline in egg production at .03 to .07% sodium in the diet, a decline in feed intake at .03 to .07% sodium, a loss in body weight at .03 to .10% sodium, and an increase in molt score at .03 to .11% sodium during the experimental period. During the posttreatment period, results comparable to the forced-molt procedure were obtained for egg production increase at .03 to .08% sodium, for egg specific gravity increase at .03 to .12% sodium, and for egg albumen thickness increase at .03 to .12% dietary sodium. Mortality was unchanged.

Animal Feed↗
PubMed1983

Nutrient and drug effects on cholesterol metabolism in the laying hen.

The laying hen is a highly dynamic model for studies of cholesterol metabolism. Cholesterol biosynthesis takes place primarily in the liver where it is regulated by both diet and drugs. Ovarian cholesterol biosynthesis follows a pattern different from that in liver and is not influenced by dietary fat or cholesterol. The hen responds to high levels of dietary polyunsaturated fat by increasing cholesterol biosynthesis, egg cholesterol deposition, and fecal bile acid excretion. Dietary cholesterol curtails liver cholesterol biosynthesis and may or may not result in increased egg cholesterol deposition and/or increased fecal steroid excretion depending on the level of cholesterol intake. Dietary plant sterols and fiber may moderate egg cholesterol deposition but the conditions under which this takes place are not well defined. D-Thyroxin reduces blood cholesterol, increases blood sterol turnover, and increases egg cholesterol concentration. Triparanol and azasterols prevent desmosterol conversion to cholesterol with resultant appearance of both sterols in blood and eggs. Probucol moderates egg cholesterol deposition by reducing synthesis and/or transfer of the sterol to the egg. Implications for the use of the hen in cholesterol metabolism studies are discussed.

Animals↗
PubMed1982

Effect of probucol on reproductive performance, egg yolk cholesterol content, and lipid metabolism in the laying hen.

Egg production type chickens were given the drug Probucol in their diets to determine its effect on egg production characteristics, liver lipid metabolism, egg yolk lipid synthesis, and egg yolk cholesterol concentration. In none of the three trials conducted did Probucol feeding affect egg production or body weight. The drug reduced total liver lipogenesis as measured by incorporation of 14C-acetate by surviving liver slices. Relative incorporation of 14C-acetate into cholesterol by liver was increased by the drug. However, in ovo incorporation of 14C-acetate in total yolk lipids remains unchanged and relative incorporation into yolk cholesterol is reduced. As a result, egg yolk cholesterol content is reduced by 5% with the .10% dietary level of drug administration.

Animals↗
PubMed1977

A nutrient re-evaluation of shell eggs.

Most data on the nutrient composition of shell eggs were obtained before 1950. Since then, management systems for egg production and analytical methods for many components have changed. Freeze-dried whole egg, yolk and white samples were prepared from eggs obtained from a single source of 15 month old White Leghorns. The sample were packaged under nitrogen and held at -20 degrees C. until analyzed. Conversion factors are included for expressing the amount of each component on a per egg as well as a per 100 g. edible liquid basis. This re-evaluation of nutrient data included total solids, lipid, protein, cholesterol, ash, calories, amino acids, fatty acids, vitamins and minerals.

Amino Acids↗
PubMed1977

The impact of contamination by organochlorine insecticides on poultry nutrition and feeding.

Nutrient interactions with organochlorine insecticides have been described primarily for vitamin A and protein. Storage of liver vitamin A is reduced by DDT and dieldrin. Low protein diets protect rats from heptachlor toxicity, whereas the toxicity of DDT, dieldrin and lindane is reduced by increasing the quantity and quality of diet protein intake. Biological performance of poultry is adversely affected by 50 to 500 ppm of most of these compounds. Hatchability of eggs and survival of chicks from hens fed insecticides are usually the most sensitive parameters of toxicity. Higher levels of DDT decrease thyroid activity. While several insecticides reduce egg shell thickness in wild birds, such changes are not observed in poultry. Extensive low level contamination of poultry tissues and eggs results from the organochlorine insecticides, with the exception of methoxychlor where tissue residues are not a problem. Tissue and egg accumulation of residues is related to dose but quantitatively different for each organochlorine compound. Tissue withdrawal and excretion takes place slowly and most of the compounds are metabolized by liver hydroxylating enzymes to various derivatives that are also stored in the body. In one case (heptachlor epoxide), the oxidation product is more toxic than the body. In one case (heptachlor epoxide), the oxidation product is more toxic than the parent compound.

Agriculture↗
PubMed1976

The cholesterol problem, the egg and lipid metabolism in the laying hen.

There is little doubt that high blood serum lipid levels are related to a higher incidence of atherosclerotic disease in humans. Experimental evidence to date suggests that dietary intervention can reduce blood lipid levels in most cases and that some small reduction in occurrence of cardiovascular disease will probably result. On the other hand no reduction in total mortality has been demonstrated in the well constructed dietary studies. It appears that there is considerable variation in the human population with regard to their patterns of lipid metabolism. Some apparently regulate body production of cholesterol in response to dietary changes, others do not. Some seem to excrete excess sterols efficiently, while some do not. It seems likely, therefore, that dietary manipulation would be useful for those disposed by heredity and other conditions to accumulation of excessive sterols in the body. On the other hand drug control of cholesterol biosynthesis and/or sterol excretion may be more effective solutions to the problem of sterol accumulation. Irrespective of whether diet or drugs prove to be the best answer to control of sterol balance, these should be applied only to that segment of the population known to require such treatment. The egg is an important dietary source of cholesterol and as a result is used sparingly in low cholesterol diets. On the other hand normal egg consumption of two eggs per day does not appear to overload cholesterol balance in the healthy human adult since depression in cholesterol biosynthesis and increased sterol excretion will result. Investigation of the lipid metabolism of the laying hen has shown that most of the cholesterol found in the egg is synthesized in the liver where it is under both dietary and drug control. Most of the cholesterol deposited in egg yolk may be essential for embryonic development. Drugs that severely limit cholesterol biosynthesis probably also limit synthesis of adrenal and sex hormones and hence limit reproduction. Moderate depressions in lipogenesis achieved without feeding of large amounts of dietary fat may offer a means for moderating cholesterol deposition in eggs. On the other hand, it also seems clear that genetic selection could be used to moderate egg cholesterol concentration. In any event, a great deal more evidence from well constructed human diet studies will be needed before low cholesterol diets can be recommended to the general population as an aid to control of cholesterol balance and heart disease.

Animal Feed↗