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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Measurement of lipids in chicken carcass dry matter.

Three procedures were used to measure the lipid fraction of chicken carcass dry matter. The resulting data were evaluated by calculating carcass residuals (carcass dry matter-protein-ash-lipid) and by application of multiple linear regression to estimate the energy values of carcass fat and protein. Petroleum ether extraction led to carcass residuals of about 5% and an estimated energy value of protein that was larger than previous estimates. Chloroform:methanol (2:1) extraction gave a negative residual (-6.5%) and a very low predicted energy value for protein. However, when the chloroform:methanol extract was corrected for crude protein content, the residual was approximately 1.0% of the dry matter, and the energy estimates were similar to those obtained previously. The importance of conducting analytical analyses in duplicate is illustrated.

The excreta energy and nitrogen losses of adult cockerels during a fast.

Sixteen adult Single Comb White Leghorn (SCWL) cockerels were fasted for 48 hr and then placed on an experiment during which they were fasted for an additional 11 days; water was freely available. Excreta energy (FE + UE), excreta nitrogen (FN + UN), and excreta energy corrected to zero nitrogen balance (FEn + UEn) losses were measured at 24-hr intervals as were body weights (BW) and weight losses (delta BW). One bird died on the second day of the experiment. There were significant differences (P less than .01) in excreta losses among birds and days. The day effect was curvilinear and decreasing, with the largest day-to-day changes tending to occur early in the experiment. The BW, delta BW, and ambient temperature had little effect on the losses with the exception of (FN + UN) which varied in part with BW. The regression of FE + UE on FN + UN, after adjusting for birds and days, yielded a slope estimate of 33.54 +/- 5.12 kJ/g (8.02 +/- 1.22 kcal/g) of nitrogen which is not different (P greater than .05) from values commonly used to corrected bio-available energy values to zero nitrogen balance.

Changes in the body weights and the final carcass compositions of adult cockerels fed less than their maintenance requirements.

Seventy-two adult Single Comb White Leghorn (SCWL) cockerels of each of two strains were fasted for 48 hr. Twenty-four birds of each strain were killed and frozen. Eight birds of each strain were fasted for an additional 11 days and 4 birds of each strain received, by intubation, 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 g of a high energy feed daily for 10 days, after which they were fasted for 48 hr. Birds were weighed and their excreta were collected at 24-hr intervals. At the conclusion of the experiment, all birds were killed and their carcasses, together with those of the initial slaughter group (IS), were assayed for water, protein, fat, and ash. All experimental birds lost weight. The change in body weight (delta BW) decreased linearly as feed input increased. Solution of the derived regression equation provided a mean estimate of .355 MJ/BW.75 kg/day (.0848 Mcal/BW.75 kg) for the energy requirement to maintain body weight. The estimate fails to take account of changes in body composition, but correction for this was impractical because of the large among bird variation. For the fasted birds, the delta BW displayed a logarithmic-decay pattern over time. Carcass protein and water increased with feed input but carcass fat was independent of feed input. However, the proportions of the carcass constituents did not vary with feed input. The proportion of carcass protein was greater and of carcass fat less at the end of the experiment than in the IS birds.

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.

The bioavailability of supplementary lysine and its effect on the energy and nitrogen excretion of adult cockerels fed diets diluted with cellulose.

A basal diet formulated to be deficient in lysine was supplemented with five levels of L-lysine monohydrochloride and each of the resulting diets was diluted with six levels of cellulose. Each of the 30 diets was precision fed (30 g/bird) to adult cockerels which had been fasted for 24 hr, and excreta voided during the 48 hr following feeding were collected. Twelve fasted birds served as controls. Feed and excreta samples were assayed for lysine, energy, and nitrogen. The bioavailability of the natural lysine was 88.2 +/- 2.5% whereas that of the L-lysine HCl was approximately 92%, significantly (P less than .05) less than the 100% often assumed in lysine requirement studies. The supplemental lysine did not significantly affect (P greater than .05) estimates of bioavailable energy [true metabolizable energy (TME), TME corrected to zero nitrogen balance (TMEn)]. Cellulose dilution had no significant (P greater than .05) effect on either lysine or energy availability.

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.

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).

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.

The effects of precision feeding on the behavior of adult cockerels.

The behavior of 15 precision-fed (PF) cockerels was compared with that of 15 normal (N) and 15 fasted (F) birds. In the 10 min after feeding, the PF birds had a higher incidence of beak movements (P less than .01) than N and F birds. Five PF birds retracted their heads and necks, and 3 made regurgitation-like movements, but the effects were generally slight and fleeting. When a flock of 48 PF birds was observed more casually, only 2 birds showed abnormal behavior. The low incidence of conspicuous abnormal behavior, after precision feeding, in contrast to that reported by Wehner and Harrold (1982), is probably due to the shorter time required to administer the feed.

Effects of dietary fat level and lysine:energy ratio on energy utilization and tissue synthesis by broiler chicks.

An experiment was designed to estimate the effect of dietary fat (20 or 80 g/kg) on the responses of broiler chicks to changes in the ratios of bioavailable lysine (LB) to true metabolizable energy corrected to zero nitrogen balance (TMEn) in their diets. A comparative slaughter experiment used an initial slaughter group of 44 10-day-old male chicks; an additional 120 chicks from the same population were used in the 14-day experiment. Dietary treatments comprised two basal diets differing in fat content and formulated to have similar nutrient:TMEn ratios. Each basal diet was supplemented with four levels of lysine to provide four LB:TMEn ratios calculated, and subsequently found, to be the same in each basal diet series. Each of the eight diets was diluted with five levels of cellulose to ensure a range of intakes under ad libitum feeding. Three individually housed chicks were assigned to each of the 40 diets. Carcasses were assayed for water, nitrogen, lipids, ash, and gross energy; changes in these variables during the experiment were the response criteria. The fat content of the diet had no effect (P greater than .05) on the chick responses to LB:TMEn ratios. At a fixed energy intake the body weight gain, retained water, retained energy as protein and retained ash increased with the LB:TMEn ratio, with no conclusive evidence of a maximum response having been reached for any variable at an LB:TMEn ratio of .83 g/MJ. Retained energy was independent (P greater than .05) of the LB:TMEn ratio but the energy retained as neutral lipids tended to decrease as the ratio increased. The data support the view that the lysine requirement of the broiler chick varies according to the response criterion used in its assessment.