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The Effect of Level of Feed Input on True Metabolizable Energy Values1
The Effect of Level of Feed Input on True Metabolizable Energy Values1 I. R. SIBBALD Animal Research Institute, Agriculture Canada, Central Experimental Farm, Ottawa, Ontario K1A 0C6 (Received for publication March 1, 1977) ABSTRACT An experiment was made in which the true metabolizable energy (T.M.E.) value of a diet was measured at levels of feed input ranging from 10 to 100 g. by 10 g. increments; there were 8 replications. At feed input levels above 40 g. per bird there was regurgitation which tended to increase in incidence and severity with the level of input. The standard errors of mean T.M.E. values decreased as the level of input increased from 10 to 30 g. per bird; at input levels above 60 g. the number of observations was reduced because regurgitated feed contaminated some excreta samples. The optimum level of feed input is approximately 40 g. when the assay bird is an adult S.C.W.L. rooster. Poultry Science 56:1662-1663, 1977 RESULTS AND DISCUSSION Twelve of the 80 force-fed birds regurgitated some feed. The amount ranged from one or two pellets to the entire amount placed in the crop. The incidence and severity of regurgitation tended to increase with the amount of feed administered. No regurgitation was observed among birds given 40 g., or less, of feed. The incidence of regurgitation is shown by the data of Table 1. The mean T.M.E. values for the diet at each level of feeding are displayed as means in Table 1. Data from birds which regurgitated were omitted from the calculations. Although the mean T.M.E. values ranged from 3.32 to 3.44 kcal./g. there was no clear trend to suggest that the level of feed input affected the ability of the bird to extract energy from the feed. The standard errors of the mean T.M.E. values decreased rapidly from 0.084 kcal./g. at the 10 g. level of feeding to 0.018 kcal./g. at the 30g. level of feeding. Increasing the feed input beyond 30 g. may have reduced the level of variation a little but at the high levels of input such effects were masked because the number of observations were reduced. If the excreta samples, contaminated with regurgitated feed, were assayed, and if the T.M.E. data were included in the calculations, then the standard errors associated with high levels of feed input would be greatly magnified.
MATERIALS AND METHODS The experiment was of a complete block design with 10 levels of a commercial, pelleted, 17% protein, turkey grower diet being fed to 8 replicated groups of adult, S.C.W.L. roosters. An additional 8 birds received no feed and served as the controls in the measurement of the metabolic fecal and endogenous urinary energy output. The assay for T.M.E. was similar to that described by Sibbald (1976) but the birds were starved for 24 hours prior to force feeding. The levels of feed input increased by 10 g. increments from 10 to 100 g. per bird. 1
tute.
Contribution number 685, Animal Research Insti-
It is concluded that as the level of feed input increases the standard error of a mean T.M.E. value decreases; however, at inputs above 40 g. per bird there is a risk of regurgitation. If a
1662
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INTRODUCTION The bioassay for true metabolizable energy (T.M.E.) involves the placement of known quantities of feed in the crops of adult roosters (Sibbald, 1976). During the development of the assay it was observed that large quantities of feed increased the incidence of regurgitation; however, it seemed probable that the effects of experimental errors would be inversely proportional to the amount of feed administered. A level of feed input approximately equal to one percent of body weight, 25 g. for an adult Single Comb White Leghorn (S.C.W.L.) rooster, was found to be satisfactory. The purpose of the present study was to measure the effect of the level of input on the T.M.E. value of a feed.
RESEARCH NOTE
1663
TABLE l.—The relationship between T.M.E. and the level of feed input
Level of feed input g./bird
Number of regurgitations
Number of T.M.E. observations
Mean T.M.E. value with standard error kcal,/g.
10 20 30 40 50 60 70 80 90 100
0 0 0 0 1 0 3 1 2 5
8 8 8 8 ~7 8 5 7 6 3
3.44 3.39 3.38 3.40 3.44 3.38 3.38 3.32 3.34 3.36
ACKNOWLEDGEMENT T h e a u t h o r is i n d e b t e d t o Mrs. S. T o b i n for her excellent technical assistance.
REFERENCE Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:970—974.
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small a m o u n t of feed is regurgitated and n o t n o t i c e d it will d i s t o r t t h e T.M.E. value. If t h e regurgitation is observed t h e excreta sample m u s t b e discarded. T o o b t a i n m a x i m u m precision in T.M.E. m e a s u r e m e n t s t h e feed i n p u t should be t h e largest a m o u n t which will n o t cause regurgitation. F o r a d u l t S.C.W.L. roosters t h e o p t i m u m feed i n t a k e is a p p r o x i m a t e l y 4 0 g. per bird.
±0.084 + 0.045 ±0.018 ± 0.022 ±0.008 ±0.012 ±0.015 ±0.020 ± 0.028 + 0.024
MATERIALS AND METHODS The experiment was of a complete block design with 10 levels of a commercial, pelleted, 17% protein, turkey grower diet being fed to 8 replicated groups of adult, S.C.W.L. roosters. An additional 8 birds received no feed and served as the controls in the measurement of the metabolic fecal and endogenous urinary energy output. The assay for T.M.E. was similar to that described by Sibbald (1976) but the birds were starved for 24 hours prior to force feeding. The levels of feed input increased by 10 g. increments from 10 to 100 g. per bird. 1
tute.
Contribution number 685, Animal Research Insti-
It is concluded that as the level of feed input increases the standard error of a mean T.M.E. value decreases; however, at inputs above 40 g. per bird there is a risk of regurgitation. If a
1662
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
INTRODUCTION The bioassay for true metabolizable energy (T.M.E.) involves the placement of known quantities of feed in the crops of adult roosters (Sibbald, 1976). During the development of the assay it was observed that large quantities of feed increased the incidence of regurgitation; however, it seemed probable that the effects of experimental errors would be inversely proportional to the amount of feed administered. A level of feed input approximately equal to one percent of body weight, 25 g. for an adult Single Comb White Leghorn (S.C.W.L.) rooster, was found to be satisfactory. The purpose of the present study was to measure the effect of the level of input on the T.M.E. value of a feed.
RESEARCH NOTE
1663
TABLE l.—The relationship between T.M.E. and the level of feed input
Level of feed input g./bird
Number of regurgitations
Number of T.M.E. observations
Mean T.M.E. value with standard error kcal,/g.
10 20 30 40 50 60 70 80 90 100
0 0 0 0 1 0 3 1 2 5
8 8 8 8 ~7 8 5 7 6 3
3.44 3.39 3.38 3.40 3.44 3.38 3.38 3.32 3.34 3.36
ACKNOWLEDGEMENT T h e a u t h o r is i n d e b t e d t o Mrs. S. T o b i n for her excellent technical assistance.
REFERENCE Sibbald, I. R., 1976. A bioassay for true metabolizable energy in feedingstuffs. Poultry Sci. 55:970—974.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
small a m o u n t of feed is regurgitated and n o t n o t i c e d it will d i s t o r t t h e T.M.E. value. If t h e regurgitation is observed t h e excreta sample m u s t b e discarded. T o o b t a i n m a x i m u m precision in T.M.E. m e a s u r e m e n t s t h e feed i n p u t should be t h e largest a m o u n t which will n o t cause regurgitation. F o r a d u l t S.C.W.L. roosters t h e o p t i m u m feed i n t a k e is a p p r o x i m a t e l y 4 0 g. per bird.
±0.084 + 0.045 ±0.018 ± 0.022 ±0.008 ±0.012 ±0.015 ±0.020 ± 0.028 + 0.024