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Biomedical subjects

I R Sibbald

Publications and source records attributed to I R Sibbald.

34 records · Page 2Linked to original sources
PubMed1981

Metabolic plus endogenous energy and nitrogen losses of adult cockerels: the correction used in the bioassay for true metabolizable energy.

Three experiments were made with adult White Leghorn cockerels to measure the effect of indigestible organic matter on the metabolic fecal and endogenous urinary energy and nitrogen losses. When a cellulose:carboxymethyl cellulose mixture was placed in the crops of fasted birds the energy excreted during the subsequent 24 and 48 hr was greater than, but proportional to, the energy input. The linear regression coefficients were not different (P greater than .05) from unity, indicating that the metabolic and endogenous energy output neither increased nor decreased when cellulose was administered. This finding was confirmed when graded levels of sawdust were fed in place of cellulose. It is concluded that the use of a fasted bird to measure the metabolic and endogenous energy loss, as in the bioassay for true metabolizable energy, is valid and the changes induced by the nature or quantity of dietary fiber are insignificant. Nitrogen excretion was not affected by the feeding of cellulose or sawdust. Excretion increased with the duration of starvation but the difference diminished as the bird aged and became heavier. Nitrogen losses varied greatly among birds but tended to be characteristic of a bird within an experiment.

Animal Feed↗
PubMed1980

The effect of the basal diet on the utilization of fat as a source of true metabolizable energy, lipid, and fatty acids.

An experiment was made to investigate the effect of diet composition on the utilization of beef tallow by adult cockerels. The birds were starved for 24 hr and then force-fed 1 of 3 basal diets (30 g) supplemented with 0, 1.5, 3.0, or 4.5 g of beef tallow. Excreta voided in the subsequent 24 hr was collected. True metabolizable energy (TME) and lipid availability values were measured. The TME value of tallow differed between basal diets and with the level of tallow input. A corn basal permitted greater TME values than a wheat basal but a supplement of soybean lecithins made the wheat basal as effective as the corn basal. Linoleic acid and phospholipid concentrations in the diet appeared to influence tallow utilization. The basic procedures of the TME bioassay permitted measurement of total lipid and fatty acid availability data. Lipid availability paralleled the TME data. Total lipid utilization ranged from 78 to 93% while the utilization of individual fatty acids varied both between acids and within acids between dietary treatments. Unsaturated fatty acids were well utilized (85 to 96%) while saturated acids were less well utilized (57 to 90%), particularly at high levels of input.

Animals↗
PubMed1980

True metabolizable energy values for poultry of commercial diets measured by bioassay and predicted from chemical data.

Data describing 419 commercial poultry feeds and 41 mixtures of feedingstuffs were used to develop multiple linear regression equations for predicting the true metabolizable energy (TME) values of mixed feeds. Equations using the three-variable combinations "ether extract, crude fiber, ash" and "ether extract, crude protein, NFE" were equally useful as predictors of TME, explaining about 80% of the variation. The combination "ether extract, crude protein, carbohydrate", used in published equations for predicting apparent metabolizable energy, explained only about 60% of the variation. Equations with four or more variables were not significantly better than the three-variable equations. The commercial data were split into three groups. Equations developed on the separate groups were consistent. The equations are recommended for use with mixed feeds whose parameters fall within the ranges of the values observed in the experiment.

Animal Nutritional Physiological Phenomena↗
PubMed1980

The effects of dietary cellulose and sand on the combined metabolic plus endogenous energy and amino acid outputs of adult cockerels.

Two experiments were made with adult, Leghorn cockerels to measure the effects of inert materials on metabolic plus endogenous (M+E) excretions. In the first experiment birds starved for 24 hr were force-fed 25 g of either a laying hen diet (OHR) or corn supplemented with 0, 1, 2, 3, or 4 g of cellulose. Excreta voided were collected quantitatively during the two 24 hr periods postfeeding. A group of 4 birds was maintained unfed. Diets and excreta were assayed for amino acids (AA) and gross energy (GE). Supplemental cellulose had no effects on AA excretion nor on the availabilities of the AA within the OHR and corn. All AA, in the form of feed residues, were excreted within 24 hr of feeding. During the period 24 to 48 hr postfeeding the OHR fed birds excreted more AA than did the corn fed birds, probably because they were less depleted in protein. The AA excretions of the unfed birds decreased with the duration of starvation. The true available AA values for the diets were calculated using a series of three corrections for M+E AA outputs. The true metabolizable energy (TME) values of the OHR and corn were unchanged by the cellulose which indicates that the cellulose contained no available energy and had no effect on the availability of the energy within the OHR and corn. It also demonstrated that the cellulose did not change the M+E energy excretion. The second experiment was a 4 X 4 factorial with four diets: nil, corn, wheat, oats (25 g/bird), and four levels of sand: 0, 1, 2, 3 g/bird. The birds were starved for 24 hr prior to feeding and excreta were collected quantitatively during the two 24 hr periods postfeeding. Feeding sand to the birds had no effect on their GE outputs but it was noted that little sand was voided within 48 hr postfeeding. The TME values were determined for the grains. A number of significant differences were observed but there was no evidence that the sand altered the TME values. It was therefore concluded that the sand had no effect on the M+E energy excretion of the assay birds. It is concluded that supplemental cellulose had no effect on the AA excretion of adult Leghorn cockerels. Neither cellulose nor sand, in the levels fed, altered M+E energy excretion. Neither diluent appeared to alter the utilization of the materials with which they were fed.

Amino Acids↗
PubMed1980

Gut clearance and true metabolizable energy value of dehydrated alfalfa supplemented with sodium chloride.

Dehydrated alfalfa (30 g), supplemented with .00, .15, .30, .45, or .60 g of sodium chloride, was force-fed to starved adult White Leghorn cockerels. The rate of clearance of alfalfa residues was not affected by the supplemental salt; there was a high level of variability between birds within treatment groups. The true metabolizable energy value of the alfalfa was unchanged by the salt.

Animals↗
PubMed1980

Variability in metabolic plus endogenous energy losses of adult cockerels and in the true metabolizable energy values and rates of passage of dehydrated alfalfa.

An experiment with four groups of 12 adult cockerels allowed true metabolizable energy (TME) to be estimated in several ways. The birds were alternately fed one of two samples of dehydrated alfalfa meal or starved to serve as a negative control for the measurement of metabolic and endogenous energy loss (FEm + UEe). Each bird was fed twice and served as a control twice. The correction for FEm + UEe, therefore, could be estimated from the same bird, at a different period, or from a different bird at the same period. The FEm + UEe was largely characteristic of the bird. The correlation of the first observation with the second observation for each bird was .744 (44 DF). Variation in body weight did little to explain variation in FEm + UEe (r = .069, 90 DF). The most precise TME estimates were obtained by using each bird as its own negative control. A group mean value for FEm + UEe was somewhat inferior but the decrease in precision may be offset by reduced time and cost. The TME values provided additional evidence that the FEm + UEe output is characteristic of the bird. Although some birds consistently voided alfalfa residues more slowly than other birds, the pattern was not sufficiently consistent between birds to be significant.

Animals↗
PubMed1980

The passage of oat and other feed residues through the adult cockerel.

Three experiments were made with adult White Leghorn cockerels to study the passage of feed residues through the alimentary canal. The birds were starved for 24 hr and then force-fed known quantities of feedingstuffs. Excreta were collected quantitatively at 2 hr intervals during the light periods, dried, and weighed. In the first two experiments the birds received 12 hr of light daily while in the third experiment continuous light was used. Residues of oats fed at levels ranging from 6 to 30 g/bird appeared in the excreta within 2 hr and continued to be voided for 52 hr. The rate and duration of residue output were functions of residue input; this was true for, wheat, fish meal, and dehydrated alfalfa as well as oats. For practical purposes the clearance times were substantially less than 52 hr for most of the inputs studied.

Animals↗
PubMed1979

Passage of feed through the adult rooster.

Five experiments were made to measure the time required for feed residues to clear the alimentary canal. The cumulative production of excreta dry matter was the primary criterion of measurement although attempts were made to adopt a stained particle technique. The latter was confounded by the production of metabolic and endogenous wastes. When full-fed adult roosters were taken off feed the residues within their alimentary canals were voided within 24 hr. Subsequent experiments involved placing known quantities of feed in the crops of starved roosters and measuring excreta production. Finely ground corn, wheat, oats, and barley (30 g) cleared the alimentary canal in 24 hr. The amount of wheat or wheat bran (10, 20, 30 g) placed in the crop affected the rate of passage but clearance was completed within 24 hr. A confounding factor was that the production of metabolic and endogenous waste decreased with the degree of starvation which was a function of feed input. Corrections based on the excreta production of negative control birds were not wholly satisfactory. The rate of excreta production was affected by the duration of starvation prior to the feeding of coarsely ground corn, soybean meal, and meat meal. The time of feeding also had a small effect. However, neither variable was of practical importance. It was found that while corn and soybean meal resideus cleared the alimentary canal in 24 hr meat meal required about 30 hr. Alfalfa, fish meal, and wheat fed as pellets produced more excreta than when fed as meals. Pellets appeared to have the faster rate of passage through the alimentary canal. Both alfalfa and fish meal required more than 24 hr to pass through the birds.

Animal Feed↗
PubMed1978

The metabolic and endogenous energy losses of adult roosters.

The metabolic plus endogenous energy losses of 300 adult, White Leghorn roosters during a 24 hr period, following 24 hr of starvation, were measured. The losses ranged from 2.37 to 6.93, with a mean of 4.46, kcal/kg body weight/24 hr. Multiple regression analysis showed that only 23% of the variation in the loss/bird/24 hr was explained by differences in body weight and weight change. The measurements were made during 38 experiments spread over 3 years but there was no evidence of any relationship between the year or time of year and magnitude of the energy loss.

Animals↗
PubMed1977

The effect of dietary phosphorus level and strain of bird on the apparent metabolizable energy content of a laying hen diet.

An experiment was made in which laying hen diets containing four different levels of dicalcium were each fed to two replicate groups of 10 strains of S.C.W.L. hens. The apparent metabolizable energy (A.M.E.) values of the diets were measured. There was a small but significant (P less than 0.01) linear increase in the dietary A.M.E. value associated with decreasing levels of phosphorus. The A.M.E. values did not differ between strains of birds (P greater than 0.05) and there was no phosphorus level x strain interaction (P greater than 0.05).

Animal Feed↗
PubMed1976

A bioassay for true metabolizable energy in feedingstuffs.

In 12 experiments with S.C.W.L. roosters it was shown that for each of 12 feedingstuffs there was a linear relationship between feed input and the amount of energy voided as excreta. In the 24 h. period, following 21 hr. of starvation, roosters receiving no feed excreted 4.07 kcal./kg. of body weight. When dextrose was fed the energy voided as excreta did not increase with dextrose input; consequently, the true metabolizable energy (T.M.E.) value of dextrose is its gross energy value. The T.M.E. values were not affected by the level of feed input and appeared to be additive. A simple, rapid assay for T.M.E. was developed, based on gross energy assays of the test feed and of excreta voided over 24 hr. by roosters force fed the test feed and other starved over the same period.

Animal Feed↗
PubMed1976

The effect of the duration of starvation of the assay bird on true metabolizable energy values.

An experiment was made with adult, S.C.W.L. roosters to measure the effect of the duration of the starvation period, prior to force feeding, on the true metabolizable energy (T.M.E.) value of a laying hen diet. Lengthening the starvation period from 24 to 96 hr., by 24 hr. intervals, had no significant effect on the T.M.E. value. The excretion of metabolic fecal + endogenous urinary energy per day tended to decrease with the duration of starvation. It is therefore, essential that the duration of the starvation period is identical for control and force fed birds. It is also essential that the duration of the experimental period is identical for both groups of birds.

Animals↗
PubMed1976

The responses of chicks to ammonium, calcium, magnesium, potassium and sodium sulphates and to ammonium and potassium carbonates.

The responses of chicks of 14 days of age to increasing levels of dietary anions and cations were investigated in two experiments. Major reductions in weight gains per chick and in gain:feed ratios were observed in chicks as levels of dietary sulphate, with ammonium or potassium cations, were increased from 0 through 5 g. per 100 g. diet. Sodium sulphate had a similar but smaller effect. Calcium and magnesium sulphates increased weight gains and gain:feed ratios at low levels of dietary inclusion. The relative effect of anion and cation were studied in the second experiment. Potassium carbonate reduced weight gains and gain:feed ratio to a greater degree than potassium sulphate; however the higher dietary levels of ammonium carbonate had little effect on chick growth responses in contrast to the major reductions obtained in response to ammonium sulphate. There were no differences between responses of strains of chicks within experiments. None of the salts were lethal at the levels fed.

Ammonium Sulfate↗
PubMed1975

Variation in the metabolizable energy values of diets and dietary components fed to adult roosters.

Two experiments were conducted to measure the variability of the M.E. values of diets and dietary ingredients fed to adult S.C.W.L. roosters. The first experiment was concerned with the variability between birds and days, the acclimatization to dietary change and the effect of the nitrogen correction. The standard error of the mean dietary M.E. value appropriate to an individual bird on one day was found to be 0.073 kcal./g. Increasing the number of days of excreta collection reduced this value slightly faster than did increasing the number of birds. The results suggest that the dietary acclimatization period should be at least 48 hr. The nitrogen correction was very small and of doubtful value. The second experiment comprised 5 bioassays in each of which 6 different samples of grain were fed at 3 levels of dietary inclusion (25, 50 and 75%) to birds drawn from the population used in the first experiment. The standard error of the mean dietary M.E. value was in agreement with the earlier value. The variance of ingredient M.E. values increased as the level of dietary inclusion decreased. Standard deviations of the mean M.E. value of an ingredient predicted from the data of the first experiment were in agreement with actual values observed in the second experiment. It is concluded that the adult rooster is suitable for use in bioassays designed to measure the M.E. values of diets and ingredients.

Acclimatization↗
PubMed1975

The effect of level of feed intake on metabolizable energy values measured with adult roosters.

Two experiments were made with S.C.W.L. roosters to test the hypothesis that the apparent M.E. value of a feedingstuff is affected by the level of intake. In the first experiment the birds were starved for 18 hr. and then fed varying amounts of whole wheat. Excreta voided during the 24 hr. experimental period was collected quantitatively and assayed for gross energy. Energy voided as excreta increased in a linear manner as the intake of wheat increased. The apparent M.E. value also varied with wheat consumption according to the equation M.E. (kcal./g.) = 3.17X - 8.5/X where: 3.17 kcal./g. is the true M.E. value of the wheat; 8.5 kcal. represents the sum of the metabolic fecal and endogenous urinary energy losses; and X is the weight of wheat consumed (g). A supplementary observation was that the metabolic fecal and endogenous nitrogen excretion of the roosters was 144 mg./kg./24 hr. In the second experiment corn oil was placed in the crops of starved roosters and the energy voided as excreta in 24 hr. was measured. The true M.E. value of the corn oil was 9.40 kcal./g. but the apparent value varied with intake. It is therefore concluded that the original hypothesis is correct. The findings of these experiments may explain some of the reported variations in M.E. data. A new approach to the assay for M.E. is proposed.

Animal Feed↗