Title: Citrus pulp for poultry litter and its subsequent feeding value for ruminants
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00027157/00001
 Material Information
Title: Citrus pulp for poultry litter and its subsequent feeding value for ruminants
Physical Description: Book
Publisher: University of Florida Agricultural Experiment Station
Publication Date: 1968
Copyright Date: 1968
 Record Information
Bibliographic ID: UF00027157
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aep0361 - LTUF
18367892 - OCLC
000929573 - AlephBibNum

Table of Contents
        Historic note
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida

Bulletin 724 (Technical)
April 1968

Citrus Pulp for Poultry Litter

and Its Subsequent

Feeding Value for Ruminants

R. H. Harms
Charles F. Simpson
P. W. Waldroup
C. B. Ammerman

Agricultural Experiment Stations
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
J. W. Sites, Dean for Research


Experiment 1: Materials Used for Poultry Litter ........ 3
Experimental Procedure......... -....----..-...........------... 4
Results and Discussion .......- .... ..--------------.... 5
Experiment 2: The Influence of Incorporating Various
Levels of Citrus By-Products into Broiler Feeds ...--------- 5
Experimental Procedure -..--...-...........------....... .------------- 6
Results and Discussion -........- -.......................- --.. 6
Experiment 3: Nutrient Digestibility of Poultry
Litter by Ruminants- .-----......--------............-...---. - 7
Experimental Procedure .... ...-...... -- - --.. ------------ 8
Results and Discussion .----..........-----------.------.-------- 9
Summary and Conclusions ----..... ----..- ----------.- 10
References -.. .-----...... ---------.---.. -.......---- ---------------- 11

Citrus Pulp for Poultry Litter and Its

Subsequent Feeding Value for Ruminants

R. H. Harms', Charles F. Simpson2, P. W. Waldroup3,
and C. B. Ammerman4

During the past few years it has been increasingly difficult to
obtain satisfactory litter for poultry houses. The situation has
resulted from increased production of poultry, and the demand
from other industries for materials used as a source of litter.
This has prompted research which has shown that many new
materials can be used as a source of litter.
Blount (1962) found that chicks reared on feather meal litter
had much improved body weights and feed conversion as com-
pared to chicks reared on wood shavings. This difference was
explained on the basis that chicks reared on the feather meal
litter were free from semi-impactions of the gizzard.
Trail (1963) compared feathers, coffee bean husks, hessian,
wood shavings, and dried grass as sources of litter for chicks.
He concluded that coffee husks and shavings were the best of the
five materials for use as poultry litter. He suggested that the
differences in performance of chicks reared on the five types of
litter might be due to the fact that the birds were eating more
of some litter than others.
Particle size appears to be an important consideration in
selecting a litter for broilers. Smith (1956) reported that corn
cobs were a good source of litter for growing broilers. However,
he found that corn cobs with a particle size less than 3/8 inch in
diameter were more suitable for litter than coarser materials.
The use of the coarser materials resulted in more breast blisters
in the broilers. Aho et al. (1955) found that wood chips were
satisfactory for poultry litter when they were 1 to 2 inches in
circumference, and were preferred to chips 3 to 4 inches in
Andrews and McPherson (1963) compared straw, sugar cane

'Nutritionist and Chairman, Department of Poultry Science
"Pathologist, Department of Veterinary Science
"Former Assistant Nutritionist, Present Address: Department of Animal
Science, University of Arkansas
'Associate Animal Nutritionist, Department of Animal Science


bagasse, wood shavings, rice hulls, ground flax, and clay for use
as poultry litter. These workers observed differences in litters
in regard to the "caking" in pens. The pens with the clay mate-
rial had practically no caking, while pens with sugar cane bagasse
had a very small amount of caking around the waterers. Oak
shavings, ground flax and rice hulls had caking over 50% to 75%
of the pen areas. The pens with straw or a mixture of rice hulls
plus straw had the caking condition over 75% to 100% of the
area. They concluded that straw does not have good physical
characteristics for litter; however, it does have good fertilizer
value. They further concluded that if litter conditions are con-
sidered important then perhaps litters other than straw would
serve equally as well. They reported that the cane bagasse had
good litter characteristics and was also high in fertilizer value.
The purpose of this study was to explore the possibility of
using dried citrus pulp as a litter for poultry houses after which
it would be used later for feeding ruminants.

Experimental Procedure
Citrus pulp was compared to kiln dried wood shavings as a
litter for a broiler house. Four pens in a broiler experimental
house, each with an area of 25 square feet, were assigned to each
litter. The depth of litter in all pens was approximately 2 inches
and required approximately 50 pounds of dried citrus pulp 'in
each pen.
Ten male and ten female day-old broiler type chicks were
placed in each pen. All chicks were fed a practical type broiler
feed which contained 22% protein, 2200 kilocalories of productive
energy per kilogram of feed, 1% calcium, and 0.65% phosphorus
(Diet 1, Table 1). A small amount of feed was placed on a filler
Table 1: Composition of Diets
Ingredients 1 2
Degerminated corn 56.70 12.74
Soybean meal 50% 34.00 38.50
Alfalfa meal 20% 3.00 3.00
Citrus pulp or citrus
seed meal ... 30.00
Corn oil 2.33 13.00
Ground limestone 1.00
Dicalcium phosphate 1.67 1.46
Iodized salt 0.40 0.40
Micro-ingredients1 0.90 0.90
'Supplied per kg of diet: 6600 I.U. vitamin A, 2200 I.C.U. vitamin Da. 2.2 mg menadione
sodium bisulfite, 4.4 mg riboflavin. 13.2 mg pantothenic acid, 500 mg iron, 1.98 mg copper,
200 mcg cobalt, 11 mg iodine, 99 meg zinc, 56 mg santoquin, 22 gms MnSO4, 39.6 mg niacin,
500 mg choline C1, and 22 mg vitamin Bi1.


flat for the first three days. For the remainder of the growing
period, a hanging tube feeder was used. Each pen contained an
automatic water fountain, and infra-red bulbs were used for
All chicks were individually weighed at four and eight weeks
of age. Feed consumption was also determined for each feeding
period, and feed efficiencies were calculated from these values.
The total litter in pens containing citrus pulp was weighed at
the beginning and end of the test in order to determine the net

Results and Discussion
Chicks reared on the citrus pulp litter had body weights and
feed efficiencies equivalent to chicks reared on the wood shavings
(Table 2). The litter in pens containing citrus pulp appeared to
be dry and in good condition with little caking or spoilage ob-
served. The weight of citrus pulp litter was almost doubled dur-
ing the eight week feeding trial with an average of 92 pounds
of litter at the end of the test. This represented a gain of 42
pounds during the feeding trial.
Table 2: Body weight and feed efficiency of broilers when reared on two dif-
ferent litters.
Body Weight Feed/Gain
Type of Litter 4 wk. 8 wk. 4 wk. 8 wk.
(gms) (Ibs)
Citrus pulp 438 1288 1.63 2.25
Wood shavings 435 1257 1.64 2.22

The results from this test indicate that citrus pulp could be
used as a litter for broiler chicks, without adversely affecting
their performance. Also, visual observations indicated that citrus
pulp was a satisfactory material for absorbing the moisture from
the droppings.
The litter from the pens containing citrus pulp was saved for
use in digestion trials reported in Experiment 3.

Mehrhof and Rusoff (1939) reported that levels of 10% to
20% of citrus meal in the diet of growing chickens resulted in
mortality rates ranging from 15% to 97%. Since it is possible
that chicks will eat a considerable amount of litter, it was thought
desirable to conduct experiments to determine if the feeding of


citrus meal produced by modern processing methods would re-
sult in the same rate of mortality as observed by Mehrhof and

Experimental Procedure
Trial 1: Eighty Vantress x White Rock broiler type chicks
were used in this experiment. At one day of age they were ran-
domized into eight groups, each containing five males and five
females. Each group was placed in a separate unit in an electric-
ally heated battery-brooder with raised wire screen floor.
Two basal diets were utilized (Table 1). The control diet was
similar to those used in commercial broiler production. The
second diet was formulated by replacing a portion of the corn
with 30 % citrus pulp. Corn oil was added to keep the diets ap-
proximately iso-caloric. Two additional diets were formulated
by blending these diets in proportions to obtain levels of 10 and
20% citrus pulp. Each diet was fed to replicate pens of chicks
from one day to four weeks of age. At the end of the feeding
period all birds were individually weighed.
Trial 2: The procedures in this experiment were the same
as those followed in Experiment 1, except that citrus seed meal
was substituted for citrus pulp in the experimental diets.

Results and Discussion
Trial 1: The incorporation of 10% citrus meal in the diet
did not result in a significant reduction of growth rate of chick-
ens (Table 3). However, the 20% level resulted in a significant
reduction in growth, and a further reduction in growth rate was
obtained when a level of 30 % citrus meal was fed. No mortality
occurred during the growing period, which indicated that levels
up to 30% of citrus meal in the diet were not toxic to growing
Table 3: Body Weight of Chicks Fed Various Levels of Citrus Pulp
Citrus Pulp
in Diet 4 Wk. Body Wt.'
(%) (gms)
0 467a
10 448a
20 387b
30 330c
1Means with different superscripts are significantly different according to Duncan's multiple
range test (1955).
Trial 2: A level of 5% citrus seed meal significantly re-
duced growth rate of chicks (Table 4). A further reduction in
growth rate was obtained with each increase in level of citrus


Table 4: Body Weight and Mortality of Chicks Fed Various Levels of Citrus
Seed Meal
Citrus Seed
Meal in Diet Body Weight' Mortality1
(%) (gms) (%)
0 433a 0a
5 350b Oa
10 310C Oa
20 214d 6.7a
30 168e 20.01
1Means with different superscripts are significantly different according to Duncan's multiple
range test (1955).
seed meal to a level of 30%. Feeding diets containing 10% or
less citrus meal resulted in no mortality of chicks. However,
when a level of 20% was fed, 6.7% of the chicks died. When
the level was increased to 30%, a significant level of mortality
was produced.
These data indicate that the citrus seed meal contains a
factor which is toxic to chicks when fed aLhigh levels. It is
indicated that in the processing method a separation of by-
products had been made since citrus seed meal was toxic and
the citrus pulp was not. Changes may have been made in their
production of citrus pulp since 1939, when citrus pulp was found
responsible for mortality in chicks (Mehrhof and Rusoff).
The birds that died in this experiment were emaciated result-
ing in reduced weight. Also a necropsy revealed splenic atrophy,
and there was histologic evidence of lymphoid depletion and '
hemorrhage in the spleen and also bone marrow hyperplasia.
This is in contrast to the observations by Mehrhof and Rusoff
(1939), where the toxicity of citrus meal resulted in ascitis (a
gelatinous fluid in the peritoneal cavity), mottled and sometimes
enlarged livers, enlargement of the gall bladder, and occasionally
sub-cutaneous edema.

The value of poultry litter as a source of nutrients for plants
has been known for many years. Eno (1962) has reviewed the
data relating to the value of poultry litter in plant nutrition,
and discussed various factors affecting such use.
Recently it has been reported that poultry litter may be an
acceptable feedstuff for animals, especially ruminants. Chance
(1965) summarized research relating to its value in ruminant

"A portion of this section previously published J. Agr. Food Chem. 14:279,


nutrition, and pointed out that the type of litter used would
S'\influence its value. Fuller (1965) reported that hydrolyzed
poultry manure was a good source of "unidentified factor" for
practical broiler feeds. Since dried citrus pulp is a feedstuff
of relatively high nutritive value (Ammerman et al, 1963; Pea-
cock & Kirk, 1959) it appeared that if it were to be used as
poultry litter, its feeding value could best be utilized by feeding
the litter to ruminants. Therefore, this experiment was con-
ducted to determine the digestibility of poultry litter containing
dried citrus pulp.

Experimental Procedure
The poultry litter used in this experiment was obtained from
chicks fed in Experiment 1. At the end of the eight-week feed-
ing period the litter was removed from the pens, dried to prevent
spoilage, and stored for the lamb feeding test.
A conventional digestibility and nitrogen balance study was
conducted using three yearling Florida native wethers averag-
ing 100 pounds in bodyweight. They were used in a three x
three latin square design having been randomly assigned to
treatment in period one. The preliminary feeding time prior
Sto fecal and urine collections was 21 days, and the collection
period was seven days. The animals were placed in metabolism
"crates two days before starting the collections. Two diets con-
Staining either 65% poultry litter (which included citrus pulp)
Sor citrus pulp were fed. A third diet, referred to as "Basal
Mixture," contained hay, corn meal, and soybean meal in a
similar proportion to that of the other two diets and was used
so that digestion coefficients could be calculated "by difference"
Table 5: Composition of Diets
Chicken Citrus Basal
Litter Pulp Mixture
Chicken litter 65.00 -
Dried citrus pulp -- 65.00
Bermudagrass hay (ground) 15.00 15.00 47.50
Corn meal 12.00 12.00 38.00
Soybean meal (50% protein) 3.00 3.00 9.50
Corn oil1 3.00 3.00 3.00
Salt, trace mineralized2 1.00 1.00 1.00
Defluorinated phosphate 1.00 1.00 1.00
Vitamins A, D, and E" + + +
1Santoquin added at 0.125% of total diet.
2The Carey Salt Co., Hutchinson, Kan. listed minimum analysis in per cent:
Fe 0.27, Mn 0.25, Cu 0.033, Co 0.01, Zn 0.005, I
"2000 I.U. vitamin A palmitate, 270 I.U. vitamin D: and 5 mg DL alpha-tocopherol added
per pound of diet.


for the poultry litter and citrus pulp. The animals were fed
800 grams of feed per head daily in two equal feedings. This
allowed either maintenance of body weight or slight gains by
all lambs during the experiment. Water was provided ad libitum.
All chemical determinations on feed, feces, and urine were made
by AOAC (1960) methods.

Results and Discussion
The poultry litter was higher in ash, considerably higher in
nitrogen similar if crude fiber, and lower in fat than the citrus
pulpjTable 6). These differences resulted in similar differences
in the composition of the mixed diets containing either 65%
poultry litter or dried citrus pulp. The poultry litter diet con--I
trained 20.6% crude protein compared with 9.2% protein for i
the citrus pulp diet.
Table 6: Nutrient Composition of Diets and Major Components'
Crude Ether Crude Free
Ash Protein Extract Fiber Extract

Chicken litter diet 8.9 20.6 4.6 13.3 52.6
Dried citrus pulp diet 6.1 9.2 5.8 13.3 65.6
Basal mixture 4.6 12.1 4.1 16.9 62.3
Chicken litter 9.5 26.5 3.0 11.8 49.2
Dried citrus pulp 5.5 8.1 3.9 11.4 71.1
1Expressed on the moisture-free basis.

The digestion coefficient for nitrogen was significantly higher
in the poultry litter diet; however, the digestibility of ether
extract was significantly higher in the citrus pulp diet (Table 7).,
Apparent digestibility for the other nutrients was similar for
the other two diets. The coefficients of digestibility for the
nutrients in either the citrus pulp portion of the diet or the
poultry litter portion as calculated "by difference" emphasized,
in particular, the greater digestibility of the nitrogen in the
Table 7: Average Digestion Coefficients for Lambs Fed Chicken Litter, Dried
Citrus Pulp, or the Basal Mixture1
Organic Crude' Ether' Crude'
Matter Protein Extract Fiber
Chicken litter diet 74.0a 79.la 79.2ab 56.5a
Dried citrus pulp diet 75.8a 51.3c 85.2a 59.6a
Basal mixture 61.8b 64.8b 74.4b 34.1b
Calculated by difference:
Chicken litter 80.7a 82.0a 85.6b 72.8a
Dried citrus pulp 83.3a 41.1b 101.4a 79.7a
'Each value represents an average of four determinations.
2Means with different superscripts are significantly different according to Duncan's multiple
range test (1955).


poultry litter. Total organic matter and crude fiber were similar
in digestibility for the two ingredients, and ether extract from
the citrus pulp was more digestible. The coefficients obtained
for citrus pulp were somewhat lower for nitrogen and higher
for ether extract and crude fiber than reported previously (Am-
merman and Arrington, 1961; Keener et al. 1957).
The nitrogen deposited in the litter primarily through drop-
pings was well utilized by the animals (Table 8). Even though
twice as much nitrogen was ingested daily from the poultry litter
than from citrus pulp, the amount of nitrogen excreted in the
feces was essentially the same (4.53 vs 4.30 grams). Since the
-protein requirement for the yearling wether is approximately
/0%o of the diet (National Research Council, 1964) and the
poultry litter contained 19.9%, it is not surprising that the
major portion of the apparently absorbed nitrogen from the
diet was eliminated through the urine. In spite of the urinary
loss the average net nitrogen retained daily by the animal con-
suming the poultry litter diet was 4.74 compared with 1.53
grams for the citrus pulp diet.

Table 8: Nitrogen Balance Data'
Chicken Citrus Basal
Nitrogen Litter Pulp Mixture
Intake, gram/day 21.90 8.90 18.03
In feces, gram/day2 4.53a 4.30a 4.63a
In urine, gram/day2 12.63a 3.07c 6.33b
Retained, grams/day2 4.74a 1.53b 2.07b
Retained, % 21.64a 17.19b 15.89b
Digested, grams/day2 17.37a 4.60c 8.40b
'Each value represents an average of three determinations.
2Means with different superscripts are significantly different according to Duncan's multiple
range test (1955).


One experiment conducted with broiler type chicks, from
one day of age to eight weeks, indicated that citrus pulp was
a satisfactory source of litter for floor pens. Growth rate of
broilers reared on citrus pulp was equal to that of those reared
on wood shavings. Visual observations of the litter indicated
that it was absorptive and served equally as well as wood shav-
ings for this purpose.
The litter from the pens containing the citrus pulp was fed
in digestibility trials to determine its value for feeding lambs.
Both nutrient digestibility and composition of the litter were
compared with that of citrus pulp. On a per cent composition


basis, nitrogen and ash of the combined droppings and citrus
pulp were greater than in the original pulp. When diets con-
taining either 65% poultry litter or 65% citrus pulp were fed
to lambs, the poultry litter had a significantly higher apparent
digestibility coefficient for crude protein and a lower digestibility
of ether extract than did the diet containing citrus pulp. Other
nutrients were of similar digestibility for the two diets. The
results suggest that dried citrus pulp can be used as a poultry
litter and subsequently fed to ruminant animals.
Two other experiments were conducted to determine whether
citrus by-products would be toxic to chicks if consumed in appre-
ciable amounts. Citrus pulp was fed in levels up to 30% of
the diet, and no mortality occurred. However, levels above 10%
of citrus seed meal resulted in an increased mortality of chicks.
The post-mortem examinations of the chicks revealed evidence
of splenic atrophy.
These data indicate that citrus pulp can be used as a satis- -
factory litter for poultry. The resulting material would be a
useful feedstuff for ruminants. However, when poultry litter
is to be used for feeding ruminants, it is essential that the,.
chickens not be given drugs that have not been given clear-
ance by the Food and Drug Administration for feeding to the


Aho, W. A., W. A. Junila and H. C. Whelden, Jr. 1955. Wood chips for
Poultry Litter. Poultry Sci. 34:1175.
Ammerman, C. B., and L. R. Arrington 1961. Re-evaluation of Citrus Pulp
as a Feed. Florida Nutrition Conference Proceedings, P. 20.
Ammerman, C. B., P. A. van Walleghem, A. Z. Palmer, J. W. Carpenter,
J. F. Hentges, and L. R. Arrington 1963. Comparative Feeding Value
of Dried Citrus Pulp and Ground Corn and Cob Meal for Fattening
Steers. Ani. Sci. Mimeo. Series No. AN64-8, Fla. Agr. Exp. Sta., Gaines-
Andrews, L. D., and B. N. McPherson 1963. Comparison of Different Types
of Materials for Broiler Litter. Poultry Sci. 42:249- 253.
A.O.A.C. Official Methods of Analysis, 9th. Ed. 1960. Association of Official
Agricultural Chemistry, Washington, D. C.
Blount, W. P. 1962. The Bird as an Experimental Animal. Proc. Nutrition
Soc. 21:53 60.
Chance, C. M. 1965. Maryland, Univ. Agr. Exp. Sta., College Park. Non-
protein Nitrogen and Poultry Litter in Ruminant Diets. Maryland Nu-
trition Conference Proceedings, P. 8.


Duncan, D. B. 1955. Multiple Range and Multiple F Tests. Biometrics 11:1.
Eno, C. F. 1966. Chicken Manure. Fla. Agr. Exp. Sta. Circ. S-140.
Fuller, Henry L. 1956. The Value of Poultry By-Products as a Source of
Protein and Unidentified Growth Factors in Broiler Rations. Poultry
Sci. 35:1143 1144.
Keener, H. A., N. F. Colovos, and R. B. Eckberg 1957. The Nutritive Value
of Dried Citrus Pulp for Dairy Cattle. New Hampshire Agr. Exp. Sta.
Bul. 438.
Mehrhof, N. R., and L. L. Rusoff 1939. Utilization of Citrus Meal for
Poultry. Proc. Seventh World's Poultry Congress, P. 209- 212.
N.R.C. 1964. Nutrient Requirements of Sheep. Publ. No. 1193. National
Research Council, Washington, D. C.
Peacock, F. M., and W. G. Kirk 1959. Comparative Feeding Value of Citrus
Pulp, Corn Seed Meal and Ground Snapped Corn for Fattening Steers
in Dry Lot. Fla. Agr. Exp. Sta. Bul. 616.
Smith, R. C. 1956. Kind of Litter and Breast Blister on Broilers. Poultry
Sci. 35:593 595.
Trail, J. C. M. 1963. Effect of Different Kinds of Litter on Growth and
Feed Efficiency in Chick Rearing. Poultry Sci. 43:169 172.


University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs