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Nutritive Value of Dried Citrus Pulp and Its Effect on Milk Yield and Milk Composition of Lactating Ewes
Nutritive Value of Dried Citrus Pulp and Its Effect on Milk Yield and Milk Composition of Lactating Ewes KOSTAS FEGEROS, GEORGE ZERVAS, SPYRIDOULA STAMOULI, and ELENI APOSTOLAKI Department of Animal Nutrition Agricultural University of Athens 75 lera Odos GR-118 55, Athens, Greece ABSTRACT
that is used as a feedstuff for ruminants. The DCP is a mixture of peel, inside portions, and culled fruits of the citrus family (e.g., orange, lemons, and grapefruit) that has been dried to produce a coarse, flakey product (10). The nutrient content of DCP is influenced by several factors, including source of fruit and type of processing (3). The DCP is a pectin-rich bulky concentrate that is high in energy and low in CP (approximately 7%) and NDF (approximately 23%); some properties are similar to roughage and promote relatively high ruminal pH (10). The DCP has been fed successfully to dairy cattle (7, 11.27, 28), beef cattle (9,22, 23), and sheep (5, 15, 19). Digestibility of DCP has been determined (1, 19). Ammerman and Henry (3) indicated that >90% of the DCP fed to animals in the US is fed to lactating cows. However, research is not available on the value of DCP for milk yield of lactating ewes. Our objective was to study the nutritive value of DCP, its nutrient utilization in rations for sheep as a replacement for cereal grains, and its effect on milk yield.
In a digestibility experiment, six adult wethers of the Karagouniko breed were used to determine the nutritive value of dried cirrus pulp. The rations consisted of 800 g of hay and 75, 150, 225, 300, 375, and 450 g of citrus pulp. The apparent digestibilities of the DM, OM, CP, ether extract, crude fiber, and N-free extract for dried citrus pulp were 78.6, 87.2, 52.7, 82.0, 93.2, and 83.1%, respectively. Energy content was estimated to be 1.66 Mcal of NErjkg of DM. In a second experiment, 26 lactating ewes of the Karagouniko breed were used to study the nutrient utilization of dried citrus pulp for milk yield when citrus pulp was used as a replacement for cereal grains. The ewes were divided into two groups immediately postweaning and fed daily 700 g of alfalfa hay, 300 g of wheat straw, and 580 or 550 g of concentrates with or without 30% citrus pulp, respectively. The inclusion of citrus pulp in rations for ewes had no significant effect on milk yield and composition but decreased the C4 to Clo fatty acids. Citrus pulp is a valuable, high energy by-product that can partly replace cereal grains in sheep rations without adverse effect on milk yield or composition. (Key words: citrus pulp, milk yield, milk composition, nutritive value)
MATERIALS AND METHODS
Abbreviation key: DCP = dried citrus pulp. INTRODUCTION
Dried citrus pulp (DCP)is the main byproduct from the citrus-processing industry
The DCP was collected from a local citrus canning factory (Laconia, Sparti, Greece). The entire pulp, including seeds and peels of oranges, was dried after extraction of juice without depectinization and extraction of molasses. The first stage in processing of DCP was the addition of lime to reduce the hydrophilic nature of the DCP because of presence of pectins. Two experiments were conducted to study the nutritive value of DCP and its effect on milk yield and composition in lactating ewes. Digestibility Experiment
Received May 26, 1994. Accepted December 29, 1994.
1995 J Dairy Sci 78:1116-1121
Six 3-yr-old Karagouniko wethers, 55-kg mean BW, were used in a complete 6 x 6 Latin 1116
1117
NUTRITIVE VALUE OF DRIED CITRUS PULP
TABLE 1. Composition of rations for the digestibility experiment. Ration Ingredient
1
2
3
4
Hay Dried citrus pulp
800 75 5.6 2.0
800 150 11.2 2.0
800 225 16.8 2.0
5
6
800 375 28.0 2.0
800 450 33.6 2.0
Wd as fed) rn)Hp04
Vitamin and mineral premix'
800 300 22.4 2.0
lContained, per kilogram 150 g of Ca. 100 mg of P, 100 g of Na, 120 mg of CO, 170 mg of I, 3000 mg of Fe, 4000 mg of M a 4ooo mg of ZO. 35 mg of Se. 3.000,000 IU of retinol, 300,000 IU of cholecalciferol, and 10,000 mg of Qtocopherol.
square that was balanced for carry-over effects to determine apparent digestibility of nutrients in DCP. Wethers were housed in metabolism stalls and had free access to water. The rations were randomly assigned to the sheep and consisted of long-stem hay and DCP. The hay was made from perennial ryegrass (Loliurn perenne) and served as the roughage source at a constant 800 g/d per wether. The DCP was used at 75, 150, 225, 300, 375, and 450 gld per wether according to digestibility determination by difference (24). Hay and DCP were offered in the feeder at the same time, once daily. All rations were supplemented with (NH4)Hpo4 to keep the Ca:P ratio constant. Ingredients and their chemical composition are shown in Tables l and 2. Each experimental period consisted of an adaptation of 10 d, followed by 7 d for feces collection. Feed samples were collected at each feeding and composited for later analysis. No orts remained. During the collection period, feces also were collected and sampled according to procedures described by ZerVas et al. (29). The energy content of DCP was estimated by the equation of Van Es (26) in megacalories of NEL.
respectively, in order to have the same energy and CP intakes by both groups. The control ration consisted of maize, barley, wheat middlings, soybean meal, and minerals; concentrate with DCP contained 30% DCP as a replacement for part of maize, barley, soybean, and wheat middlings (Table 3). The soybean meal content of the concentrates differed in order to provide the same CP content for both rations. The chemical composition of roughages and concentrates is shown in Table 4. Water was offered for ad libitum intake. All ewes were fed individually, twice a day. The DCP used in this experiment was from the
Ewe Yield Experlment
MDF ADF
TABLE 2. Chemical composition of hay and dried citrus pulp (Dcp) used in the digestibility experiment. ~
91.3
DM,
-
Ash OM CP
crude fiber Ether extract N-FW extract
Twenty-six lactating ewes of the Karagouniko breed, 50-kg mean BW and 2 to ca 4 yr old, were divided into two groups, P balanced according to milk yield immediately Mg after weaning their lambs (42 d postpartum), and used in a crossover design. The ewes were Fe fed daily 700 g of alfalfa hay and 300 g of c u wheat straw plus 550 g of control concentrate za or 580 g of the concentrate containing DCP, Mn
DCP
Hay
Nutrient
90.4 (% of DM)
-
9.15 90.85 12.73 33.10 2.06 42.96
16.85 83.15 7.75 11.15 4.92 59.33 46.5 19.4 35.5 12.8 Cgncg of DM) 8.1 70.0 5.7 4.8 1.5 2.0 (m@g of DM) 358 170 I1 6.5 53 4.5 29 5.1
-
-
-
-
Journal of Dairy Science Vol. 78, No. 5, 1995
1118
FEGEROS ET AL.
TABLE 3. Composition of concentrates in the milk yield experiment. concentrate Ingredient
Control
DCP'
-(% as fed) Maize Barley Wheat middlings soybean mcal Dried citrus pulp CaCO3 N ) H p 0 4
salt
28 30 30 10
20 15 20 13
...
30
...
1
...
1
.5
.5
Vitamin and mineral ~ ~ m i x 2 .5
.5
lcontained 30% dried citrus pulp. Xontained, per kilogram, 150 g of GI,100 mg of P, 100 g of Na. 120 mg of CO, 170 mg of I. 3000 mg of Fe, 4OOO rng of Mn. 4OOO mg of Zn, 35 mg of Se, 3.000.000 IU of retinol, 300,000 IU of cholecalciferol, and 10,000 mg of a-tocopherol.
same batch as that used in the digestibility experiment. Ration selectivity did not occur, and no orts were left from alfalfa hay, straw, or concentrate after each feeding. The DM intake was 28.3 and 28.8 g k g of BW for the control and DCP rations, respectively (Table 5). Weights and body condition scores of ewes were determined at the beginning of each experimental period. No change occurred in BW or in body condition (scored approximately 2 on a five-point scale, where 1 = obese to 5 = thin) of the ewes from the start to the end of the experiment because the ration met exactly the requirements of the ewes (12). Experimental periods were 17 d. Ewes were milked twice daily, and milk weights were recorded at each milking for each experimental
period. Milk samples were collected at each milking for each collection week within each experimental period and composited on the basis of percentage volume (5%) for compositional analysis. Analyses
Samples of feedstuffs and feces were analyzed according to the Weende procedure (4). Milk fat, protein, and lactose contents were determined by infrared spectroscopy (MdkoScan 131; A / S N. Foss Electronic, Hillerd, Denmark) after adjustment by Gerber, Kjeldahl, and chloramine-T methods, respectively (2). Fatty acid concentrations were determined following preparation of fatty acid methyl esters according to the official method of the European Economic Community (8) and analyzed by chromatography (83108 PerkinElmer; Norwalk, CT). The column used was 2 m long and had 3.2 mm i.d. packed with W.HP chromosorb 10% EGSS-X (Supelco, Bellefonte, PA). Oven temperature was raised from 90 to 19O'C at a rate of 4"C/min, and carrier gas (N2) flow rate was 30 mumin. A simple ANOVA was used for digestion coefficients. All other data of milk study were subjected to least squares analysis, and significance was declared at P -c .05 (Duncan test) according to methods described by Steel and Tome (25). RESULTS AND DISCUSSION
The results for nutrient digestibility and energy content of DCP (Table 6) were quite
TABLE 4. Chemical composition of alfalfa hay, straw, and concentrates in the milk yield experiment. Concentrate
wheat
Nutrient
Alfalfa hay
StraW
Control
JXP'
DM, %
91.2
92.8
90.3
90.6
Ash OM CP Ether extract crude fiber N-Free extract
12.8 87.2 21.3 2.3 24.7 39.0
7.7 92.3 1.5 1.5 43.6 45.7
4.4 95.6 16.1 3.3 6.9 69.1
8.9 91.1 17.5 1.7 9.6 60.2
'Contained 30% dried citrus pulp.
Journal of Dairy Science Vol. 78, No. 5, 1995
1119
NUTRITIVE VALUE OF DRIED CITRUS PULP TABLE 5. Daily energy and nutrient intakes by ewe per treatment in the milk yield experiment.
TABLE 7. Effect of dried citrus pulp W P ) on milk yield and composition of dairy ewes in the milk yield study. Concentrate
Concentrate Control
Control DCP1
SEM
Effect
Milk yield, g/d
39 824
32
6% FCM. g/d
915
NSz NS NS NS NS
DCP' Ewes. no.
Energy per ewe, Mcal of h'EL/d
1.76 1.76 (g/d per ewe)
-
Nutrient DM CP Crude fiber Ether extract N-Free extract
-
1413 220 313 35 720
1441 232 330 26 693
Fat, % CP, % Lactose, %
7.04 5.36 4.68
39 784 894 7.27 5.32 4.64
30 .07
.04 .02
~~
l C o n m e d 30% DCP.
ZP > .05.
1Contained 30% dried citrus pulp.
similar to those previously reported (6, 18, 20), except for CP digestibility, which was lower in our experiment. The protein of DCP was not as digestible as that of corn, but the fiber was more digestible (5). The apparent digestibilities of DM, CP, ether extract, N-freeextract, and gross energy of diets containing up to 30% DCP were unaffected by the inclusion of DCP; the digestibility of crude fiber was significantly increased (13, 23). b o s l i et al. (16) characterized DCP as a high fiber concentrate having about 85% of the digestible energy of corn. The energy content of DCP was estimated to be 1.66 Mcal of N E L k g of DM (Table 6), which is lower than that reported by the NRC (21). This energy content may reflect the quality of the raw material, including source of fruit and type of processing (3).
TABLE 6. Digestibilities of hay and 30% dried citrus pulp @CP) and their energy content in the digestibility experiment. Nutrient
Hay
-X DM
OM CP Ether extract Crude fiber N-Free extract NEL
60.9 64.1 61.4 57.3 65.1 66.0
DCP SEM .9 .8 1.4 2.2 1.0 1.8
-
(%I X
SEM 78.6 1.5 87.2 2.8 52.7 1.7 82.0 2.3 93.2 2.6 83.1 2.8 (McavLg Of DM)
1.23
-
1.66
Table 5 shows the daily energy and nutrient intake by the ewes. Rations were isocaloric and isonitrogenous. The replacement of some grains, soybean meal, and wheat middlings by DCP at 30% of the concentrate or at 10% of the total ration DM did not significantly affect milk or FCM yields or fat, protein, and lactose contents of milk (Table 7). Research is lacking on the value of DCP for milk yield. Van Horn et al. (27) evaluated DCP as a replacement for ground corn at 8 or 43% of total ration. Milk yield was uninfluenced by amount of pulp; however, FCM yield and milk
on fatty acid TABLE 8. Effect of dried citrus pulp composition of milk fat of lactating ewes, milk study. ~~
Ration
Fatty acid Butyric Caproic caprylic Capric Lauric Myristic Palmitic Palmitoleic stearic Oleic Linoleic Linolenic
Control DCP1
SEM
Effect
3.45 2.78 2.48 7.55 4.62 11.97 27.93 3.88 8.45 22.20 3.64 .95
.13 .08 .10 .35 .19 1.30 .53 .14 .27 .5 1 .18
* ** *
-(%) 3.07 2.37 2.11 6.50 4.89 12.39 28.25 4.19 8.79 22.72 3.70 1.02
.04
*
NS2 NS NS NS NS NS NS NS
1Containcd 30% DCP.
ZP > .os. *P c .05. **P < .01. J o d of Dairy Science Vol. 78. No. 5, 1995
1120
FEGEROS ET AL.
fat percentage were greater with the hlgher concentration of DCP as a replacement for corn. Milk yield and composition did not differ when DCP was used to replace ear corn meal (17) or corn and barley (14) in dairy cow rations. Fatty acid composition of milk triglycerides was affected by DCP (Table 8). When DCP was fed, weight percentage (g/lOO g) of butyric, caproic, caprylic, and capric fatty acids decreased (P c .OS). The long-chain fatty acids were unaffected by treatment. In conclusion, DCP can be used effectively in concentrate rations fed to lactating sheep up to 10% of total DM. This feedstuff also has value as a fiber source. ACKNOWLEDGMENTS
The authors gratefully acknowledge the technical assistance of J. Vastardis, C. Grammaticakis, and E. Katsarou and express their thanks to Laconia Citrus Canning Factory, which provided the DCP. REFERENCES 1 Accardi, F.. G. Letto. M. L. Alicata, and P. Giaccone.
1976. Digestibility of orange and lemon dried pulps. Its nutritive value determination. Zootech. Nutr. Anim. 2:69. 2 American Public Health Association. 1960. Standard Methods for the Examination of Dairy Products. 11th ed. Am. Publ. Health Assoc., Washington, DC. 3 Ammennan, C. B. and P. R. Henry. 1991. Citrus and vegetable products for ruminant animals. Page 103 in Proc. Alternative Feeds for Dairy and Beef Cattle, St. Louis, MO. 4Association of Official Analytical Chemists Intemational. 1990. Official Methods of Analysis. Vol. I. 15th ed. AOAC, Arlington, VA. 5 Bhattacharya, A. N., and M. Harb. 1973. Dried citrus pulp as a grain replacement for Awassi lambs. J. Anim. Sci. 361175. 6 Boucque, C. V.. and L. 0. Fiems. 1988. Vegetable byproducts of agroindustrial origin. Livest. Prod. Sci. 19: 97. 7 Economidis, S. 1974. The effect of dried citrus pulp and grape marc on milk yield and milk composition of dairy cows. Tech. Paper No. 7. Agric. Res. Inst., Nicosia, Cyprus. 8 European Economic Community. 1977. Specific methods for methyl esters preparation of fatty acids with 4 or more C. EEC Reg. 72/77. Offic. Newspaper Eur.Econ. Commun. Jan. 15, 1977 No. N 12/11, Eur. Econ. Commun., Brussels, Belgium. Journal of Dairy Science Vol. 78, No. 5, 1995
9 Hadjipanagiotou. M., and A. Louca. 1976. A note on the value of dried citrus pulp and grape marc as barley replacement in calf fattening diets. Anim. Prod. 23: 129. 10 Harris,B. 1991. Value of high-fiber alternative feedstuffs as extenders of roughage sources. Page 138 in Roc. Alternative Feeds for Dairy and Beef Cattle, St. Louis, MO. 11 Hutton, K. 1987. Citrus pulp in formulated diets. Page 297 in Recent Advances in Animal Nutrition in AusM a . D. J. Faml, ed. Dep. Biochem. Microbiol. Nutr., Univ. New England, Armidale, New South Wales, Australia. 12Kalaisakis. P. 1982. Requirements for sheep and goats. Page 317 in Applied Animal Nutrition. P. Kalaisakis, ed. Dep. Anim. Nutr., Agric. Univ. Athens. Athens, Greece. 13Karalazos, A., D. Dotas, and I. Delidmacos. 1992. The effect of different levels of dried citrus pulp on the digestibility of sheep diets. Anim. Sci. Rev. 15:63. 14Lanza A. 1984. Dried citrus pulp in animal feeding. Page 189 in Developments in Food Science. Food Industries and the Environment. 15 Loggins, P. E.,C. B. Ammennan, J. E. Moore, and C. F. Simpson. 1966. Addition of long hay and sodium bicarbonate to pelleted and meal lamb diets high in citrus pulp. J. Anim. Sci. 25:263.(Abstr.) 16Loosli, J. K., E. E. Battley. W. P. Flatt, N. L. Jacobson, C. H. Noller, and M. Ronning. 1971. Nutrient Rqukrnents of Dairy Cattle. 4th rev. ed. Natl. Acad. Sci.. Washington, DC. 17Lucci. C.D.S., L. Velloso. N. Masotti, F. P. Renno, and M. Becker. 1975. Dried orange pulp compared with maize ear meal in concentrate mixtures for lactating cows. Rev. Fac. Med. Vet. Zootec. Univ. Sao Paolo 12:163. 18Martinez-Pascual, J., and J. Fernandez Carmona. 1980. Composition of citrus pulp. Anim. Feed Sci. Technol. 5:l. 19Martinez-Pascual, J., and J. Femandez Carmona. 1980. Citrus pulp in diets for fattening lambs. Anim. Feed Sci. Technol. 5:11. 20 Morgan, D. E.. and H.Trinder. 1980. The composition and nutritional value of some tropical and sub-tropical by-products. Page 91 in By-products and Waste in Animal Feeding. Occas. Publ. 3, 1980. E. R. Plrskov, ed. Br. Soc. Anim. Prod., Reading, England. 21 National Research Council. 1989. Nutrient Requirements of Dairy Cattle. 6th rev. ed. Natl. Acad. Sci., Washington, DC. 22 Pinzon. F. J.. and J. M. Wing. 1975. Effects of citrus pulp in high urea rations for steers. J. Dairy Sci. 59: 1100. 23 Schaibly, G. E., and J. M. Wing. 1974. Effect of roughage concentrate ratio on digestibility and rumen fermentation of corn silagetitrus pulp rations. J. h i m . Sci. 38:697. 24 Schneider. B. H., and W.Flatt. 1975. The Evaluation of Feeds Through Digestibility Experiments. Univ. Georgia Press. Athens.
NUTRITIVE VALUE OF DRIED CITRUS PULP 25Stee.l. R.C.D., and J. H. Tome. 1980. Principles and Procedures of Statistics: A Biometrical Approach. 2nd ed. McGraw-Hill Book Co., New York, NY. 26 Van Es, A.J.H. 1978. Feed evaluation for N&antS. Livest. Prod. Sci. 5:331. 27 Van Horn. H. H.,S. P. Marshall, C. J. Wilcox. P. F. Randel. and I. M.Wing. 1975. Complete rations for dairy cattle. 11. Evaluation of protein percent and
1121
quality and citrus pulp-corn substitutions. J. Dairy Sci. 58:1101.
28 Wing, J. M. 1974. Effect of physical form and amount of citrus pulp on utilization of complete feeds for dairy cattle. J. Dairy Sci. 58:63. 29Zervas. G., K. Feggeros. E. Karountzou. and G. Papadopoulos. 1990. Nutritive evaluation of whole cotton seed for sheep. Anim. Sci. Rev. 11:25.
Journal of Dairy Science Vol. 78, No. 5, 1995
that is used as a feedstuff for ruminants. The DCP is a mixture of peel, inside portions, and culled fruits of the citrus family (e.g., orange, lemons, and grapefruit) that has been dried to produce a coarse, flakey product (10). The nutrient content of DCP is influenced by several factors, including source of fruit and type of processing (3). The DCP is a pectin-rich bulky concentrate that is high in energy and low in CP (approximately 7%) and NDF (approximately 23%); some properties are similar to roughage and promote relatively high ruminal pH (10). The DCP has been fed successfully to dairy cattle (7, 11.27, 28), beef cattle (9,22, 23), and sheep (5, 15, 19). Digestibility of DCP has been determined (1, 19). Ammerman and Henry (3) indicated that >90% of the DCP fed to animals in the US is fed to lactating cows. However, research is not available on the value of DCP for milk yield of lactating ewes. Our objective was to study the nutritive value of DCP, its nutrient utilization in rations for sheep as a replacement for cereal grains, and its effect on milk yield.
In a digestibility experiment, six adult wethers of the Karagouniko breed were used to determine the nutritive value of dried cirrus pulp. The rations consisted of 800 g of hay and 75, 150, 225, 300, 375, and 450 g of citrus pulp. The apparent digestibilities of the DM, OM, CP, ether extract, crude fiber, and N-free extract for dried citrus pulp were 78.6, 87.2, 52.7, 82.0, 93.2, and 83.1%, respectively. Energy content was estimated to be 1.66 Mcal of NErjkg of DM. In a second experiment, 26 lactating ewes of the Karagouniko breed were used to study the nutrient utilization of dried citrus pulp for milk yield when citrus pulp was used as a replacement for cereal grains. The ewes were divided into two groups immediately postweaning and fed daily 700 g of alfalfa hay, 300 g of wheat straw, and 580 or 550 g of concentrates with or without 30% citrus pulp, respectively. The inclusion of citrus pulp in rations for ewes had no significant effect on milk yield and composition but decreased the C4 to Clo fatty acids. Citrus pulp is a valuable, high energy by-product that can partly replace cereal grains in sheep rations without adverse effect on milk yield or composition. (Key words: citrus pulp, milk yield, milk composition, nutritive value)
MATERIALS AND METHODS
Abbreviation key: DCP = dried citrus pulp. INTRODUCTION
Dried citrus pulp (DCP)is the main byproduct from the citrus-processing industry
The DCP was collected from a local citrus canning factory (Laconia, Sparti, Greece). The entire pulp, including seeds and peels of oranges, was dried after extraction of juice without depectinization and extraction of molasses. The first stage in processing of DCP was the addition of lime to reduce the hydrophilic nature of the DCP because of presence of pectins. Two experiments were conducted to study the nutritive value of DCP and its effect on milk yield and composition in lactating ewes. Digestibility Experiment
Received May 26, 1994. Accepted December 29, 1994.
1995 J Dairy Sci 78:1116-1121
Six 3-yr-old Karagouniko wethers, 55-kg mean BW, were used in a complete 6 x 6 Latin 1116
1117
NUTRITIVE VALUE OF DRIED CITRUS PULP
TABLE 1. Composition of rations for the digestibility experiment. Ration Ingredient
1
2
3
4
Hay Dried citrus pulp
800 75 5.6 2.0
800 150 11.2 2.0
800 225 16.8 2.0
5
6
800 375 28.0 2.0
800 450 33.6 2.0
Wd as fed) rn)Hp04
Vitamin and mineral premix'
800 300 22.4 2.0
lContained, per kilogram 150 g of Ca. 100 mg of P, 100 g of Na, 120 mg of CO, 170 mg of I, 3000 mg of Fe, 4000 mg of M a 4ooo mg of ZO. 35 mg of Se. 3.000,000 IU of retinol, 300,000 IU of cholecalciferol, and 10,000 mg of Qtocopherol.
square that was balanced for carry-over effects to determine apparent digestibility of nutrients in DCP. Wethers were housed in metabolism stalls and had free access to water. The rations were randomly assigned to the sheep and consisted of long-stem hay and DCP. The hay was made from perennial ryegrass (Loliurn perenne) and served as the roughage source at a constant 800 g/d per wether. The DCP was used at 75, 150, 225, 300, 375, and 450 gld per wether according to digestibility determination by difference (24). Hay and DCP were offered in the feeder at the same time, once daily. All rations were supplemented with (NH4)Hpo4 to keep the Ca:P ratio constant. Ingredients and their chemical composition are shown in Tables l and 2. Each experimental period consisted of an adaptation of 10 d, followed by 7 d for feces collection. Feed samples were collected at each feeding and composited for later analysis. No orts remained. During the collection period, feces also were collected and sampled according to procedures described by ZerVas et al. (29). The energy content of DCP was estimated by the equation of Van Es (26) in megacalories of NEL.
respectively, in order to have the same energy and CP intakes by both groups. The control ration consisted of maize, barley, wheat middlings, soybean meal, and minerals; concentrate with DCP contained 30% DCP as a replacement for part of maize, barley, soybean, and wheat middlings (Table 3). The soybean meal content of the concentrates differed in order to provide the same CP content for both rations. The chemical composition of roughages and concentrates is shown in Table 4. Water was offered for ad libitum intake. All ewes were fed individually, twice a day. The DCP used in this experiment was from the
Ewe Yield Experlment
MDF ADF
TABLE 2. Chemical composition of hay and dried citrus pulp (Dcp) used in the digestibility experiment. ~
91.3
DM,
-
Ash OM CP
crude fiber Ether extract N-FW extract
Twenty-six lactating ewes of the Karagouniko breed, 50-kg mean BW and 2 to ca 4 yr old, were divided into two groups, P balanced according to milk yield immediately Mg after weaning their lambs (42 d postpartum), and used in a crossover design. The ewes were Fe fed daily 700 g of alfalfa hay and 300 g of c u wheat straw plus 550 g of control concentrate za or 580 g of the concentrate containing DCP, Mn
DCP
Hay
Nutrient
90.4 (% of DM)
-
9.15 90.85 12.73 33.10 2.06 42.96
16.85 83.15 7.75 11.15 4.92 59.33 46.5 19.4 35.5 12.8 Cgncg of DM) 8.1 70.0 5.7 4.8 1.5 2.0 (m@g of DM) 358 170 I1 6.5 53 4.5 29 5.1
-
-
-
-
Journal of Dairy Science Vol. 78, No. 5, 1995
1118
FEGEROS ET AL.
TABLE 3. Composition of concentrates in the milk yield experiment. concentrate Ingredient
Control
DCP'
-(% as fed) Maize Barley Wheat middlings soybean mcal Dried citrus pulp CaCO3 N ) H p 0 4
salt
28 30 30 10
20 15 20 13
...
30
...
1
...
1
.5
.5
Vitamin and mineral ~ ~ m i x 2 .5
.5
lcontained 30% dried citrus pulp. Xontained, per kilogram, 150 g of GI,100 mg of P, 100 g of Na. 120 mg of CO, 170 mg of I. 3000 mg of Fe, 4OOO rng of Mn. 4OOO mg of Zn, 35 mg of Se, 3.000.000 IU of retinol, 300,000 IU of cholecalciferol, and 10,000 mg of a-tocopherol.
same batch as that used in the digestibility experiment. Ration selectivity did not occur, and no orts were left from alfalfa hay, straw, or concentrate after each feeding. The DM intake was 28.3 and 28.8 g k g of BW for the control and DCP rations, respectively (Table 5). Weights and body condition scores of ewes were determined at the beginning of each experimental period. No change occurred in BW or in body condition (scored approximately 2 on a five-point scale, where 1 = obese to 5 = thin) of the ewes from the start to the end of the experiment because the ration met exactly the requirements of the ewes (12). Experimental periods were 17 d. Ewes were milked twice daily, and milk weights were recorded at each milking for each experimental
period. Milk samples were collected at each milking for each collection week within each experimental period and composited on the basis of percentage volume (5%) for compositional analysis. Analyses
Samples of feedstuffs and feces were analyzed according to the Weende procedure (4). Milk fat, protein, and lactose contents were determined by infrared spectroscopy (MdkoScan 131; A / S N. Foss Electronic, Hillerd, Denmark) after adjustment by Gerber, Kjeldahl, and chloramine-T methods, respectively (2). Fatty acid concentrations were determined following preparation of fatty acid methyl esters according to the official method of the European Economic Community (8) and analyzed by chromatography (83108 PerkinElmer; Norwalk, CT). The column used was 2 m long and had 3.2 mm i.d. packed with W.HP chromosorb 10% EGSS-X (Supelco, Bellefonte, PA). Oven temperature was raised from 90 to 19O'C at a rate of 4"C/min, and carrier gas (N2) flow rate was 30 mumin. A simple ANOVA was used for digestion coefficients. All other data of milk study were subjected to least squares analysis, and significance was declared at P -c .05 (Duncan test) according to methods described by Steel and Tome (25). RESULTS AND DISCUSSION
The results for nutrient digestibility and energy content of DCP (Table 6) were quite
TABLE 4. Chemical composition of alfalfa hay, straw, and concentrates in the milk yield experiment. Concentrate
wheat
Nutrient
Alfalfa hay
StraW
Control
JXP'
DM, %
91.2
92.8
90.3
90.6
Ash OM CP Ether extract crude fiber N-Free extract
12.8 87.2 21.3 2.3 24.7 39.0
7.7 92.3 1.5 1.5 43.6 45.7
4.4 95.6 16.1 3.3 6.9 69.1
8.9 91.1 17.5 1.7 9.6 60.2
'Contained 30% dried citrus pulp.
Journal of Dairy Science Vol. 78, No. 5, 1995
1119
NUTRITIVE VALUE OF DRIED CITRUS PULP TABLE 5. Daily energy and nutrient intakes by ewe per treatment in the milk yield experiment.
TABLE 7. Effect of dried citrus pulp W P ) on milk yield and composition of dairy ewes in the milk yield study. Concentrate
Concentrate Control
Control DCP1
SEM
Effect
Milk yield, g/d
39 824
32
6% FCM. g/d
915
NSz NS NS NS NS
DCP' Ewes. no.
Energy per ewe, Mcal of h'EL/d
1.76 1.76 (g/d per ewe)
-
Nutrient DM CP Crude fiber Ether extract N-Free extract
-
1413 220 313 35 720
1441 232 330 26 693
Fat, % CP, % Lactose, %
7.04 5.36 4.68
39 784 894 7.27 5.32 4.64
30 .07
.04 .02
~~
l C o n m e d 30% DCP.
ZP > .05.
1Contained 30% dried citrus pulp.
similar to those previously reported (6, 18, 20), except for CP digestibility, which was lower in our experiment. The protein of DCP was not as digestible as that of corn, but the fiber was more digestible (5). The apparent digestibilities of DM, CP, ether extract, N-freeextract, and gross energy of diets containing up to 30% DCP were unaffected by the inclusion of DCP; the digestibility of crude fiber was significantly increased (13, 23). b o s l i et al. (16) characterized DCP as a high fiber concentrate having about 85% of the digestible energy of corn. The energy content of DCP was estimated to be 1.66 Mcal of N E L k g of DM (Table 6), which is lower than that reported by the NRC (21). This energy content may reflect the quality of the raw material, including source of fruit and type of processing (3).
TABLE 6. Digestibilities of hay and 30% dried citrus pulp @CP) and their energy content in the digestibility experiment. Nutrient
Hay
-X DM
OM CP Ether extract Crude fiber N-Free extract NEL
60.9 64.1 61.4 57.3 65.1 66.0
DCP SEM .9 .8 1.4 2.2 1.0 1.8
-
(%I X
SEM 78.6 1.5 87.2 2.8 52.7 1.7 82.0 2.3 93.2 2.6 83.1 2.8 (McavLg Of DM)
1.23
-
1.66
Table 5 shows the daily energy and nutrient intake by the ewes. Rations were isocaloric and isonitrogenous. The replacement of some grains, soybean meal, and wheat middlings by DCP at 30% of the concentrate or at 10% of the total ration DM did not significantly affect milk or FCM yields or fat, protein, and lactose contents of milk (Table 7). Research is lacking on the value of DCP for milk yield. Van Horn et al. (27) evaluated DCP as a replacement for ground corn at 8 or 43% of total ration. Milk yield was uninfluenced by amount of pulp; however, FCM yield and milk
on fatty acid TABLE 8. Effect of dried citrus pulp composition of milk fat of lactating ewes, milk study. ~~
Ration
Fatty acid Butyric Caproic caprylic Capric Lauric Myristic Palmitic Palmitoleic stearic Oleic Linoleic Linolenic
Control DCP1
SEM
Effect
3.45 2.78 2.48 7.55 4.62 11.97 27.93 3.88 8.45 22.20 3.64 .95
.13 .08 .10 .35 .19 1.30 .53 .14 .27 .5 1 .18
* ** *
-(%) 3.07 2.37 2.11 6.50 4.89 12.39 28.25 4.19 8.79 22.72 3.70 1.02
.04
*
NS2 NS NS NS NS NS NS NS
1Containcd 30% DCP.
ZP > .os. *P c .05. **P < .01. J o d of Dairy Science Vol. 78. No. 5, 1995
1120
FEGEROS ET AL.
fat percentage were greater with the hlgher concentration of DCP as a replacement for corn. Milk yield and composition did not differ when DCP was used to replace ear corn meal (17) or corn and barley (14) in dairy cow rations. Fatty acid composition of milk triglycerides was affected by DCP (Table 8). When DCP was fed, weight percentage (g/lOO g) of butyric, caproic, caprylic, and capric fatty acids decreased (P c .OS). The long-chain fatty acids were unaffected by treatment. In conclusion, DCP can be used effectively in concentrate rations fed to lactating sheep up to 10% of total DM. This feedstuff also has value as a fiber source. ACKNOWLEDGMENTS
The authors gratefully acknowledge the technical assistance of J. Vastardis, C. Grammaticakis, and E. Katsarou and express their thanks to Laconia Citrus Canning Factory, which provided the DCP. REFERENCES 1 Accardi, F.. G. Letto. M. L. Alicata, and P. Giaccone.
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9 Hadjipanagiotou. M., and A. Louca. 1976. A note on the value of dried citrus pulp and grape marc as barley replacement in calf fattening diets. Anim. Prod. 23: 129. 10 Harris,B. 1991. Value of high-fiber alternative feedstuffs as extenders of roughage sources. Page 138 in Roc. Alternative Feeds for Dairy and Beef Cattle, St. Louis, MO. 11 Hutton, K. 1987. Citrus pulp in formulated diets. Page 297 in Recent Advances in Animal Nutrition in AusM a . D. J. Faml, ed. Dep. Biochem. Microbiol. Nutr., Univ. New England, Armidale, New South Wales, Australia. 12Kalaisakis. P. 1982. Requirements for sheep and goats. Page 317 in Applied Animal Nutrition. P. Kalaisakis, ed. Dep. Anim. Nutr., Agric. Univ. Athens. Athens, Greece. 13Karalazos, A., D. Dotas, and I. Delidmacos. 1992. The effect of different levels of dried citrus pulp on the digestibility of sheep diets. Anim. Sci. Rev. 15:63. 14Lanza A. 1984. Dried citrus pulp in animal feeding. Page 189 in Developments in Food Science. Food Industries and the Environment. 15 Loggins, P. E.,C. B. Ammennan, J. E. Moore, and C. F. Simpson. 1966. Addition of long hay and sodium bicarbonate to pelleted and meal lamb diets high in citrus pulp. J. Anim. Sci. 25:263.(Abstr.) 16Loosli, J. K., E. E. Battley. W. P. Flatt, N. L. Jacobson, C. H. Noller, and M. Ronning. 1971. Nutrient Rqukrnents of Dairy Cattle. 4th rev. ed. Natl. Acad. Sci.. Washington, DC. 17Lucci. C.D.S., L. Velloso. N. Masotti, F. P. Renno, and M. Becker. 1975. Dried orange pulp compared with maize ear meal in concentrate mixtures for lactating cows. Rev. Fac. Med. Vet. Zootec. Univ. Sao Paolo 12:163. 18Martinez-Pascual, J., and J. Fernandez Carmona. 1980. Composition of citrus pulp. Anim. Feed Sci. Technol. 5:l. 19Martinez-Pascual, J., and J. Femandez Carmona. 1980. Citrus pulp in diets for fattening lambs. Anim. Feed Sci. Technol. 5:11. 20 Morgan, D. E.. and H.Trinder. 1980. The composition and nutritional value of some tropical and sub-tropical by-products. Page 91 in By-products and Waste in Animal Feeding. Occas. Publ. 3, 1980. E. R. Plrskov, ed. Br. Soc. Anim. Prod., Reading, England. 21 National Research Council. 1989. Nutrient Requirements of Dairy Cattle. 6th rev. ed. Natl. Acad. Sci., Washington, DC. 22 Pinzon. F. J.. and J. M. Wing. 1975. Effects of citrus pulp in high urea rations for steers. J. Dairy Sci. 59: 1100. 23 Schaibly, G. E., and J. M. Wing. 1974. Effect of roughage concentrate ratio on digestibility and rumen fermentation of corn silagetitrus pulp rations. J. h i m . Sci. 38:697. 24 Schneider. B. H., and W.Flatt. 1975. The Evaluation of Feeds Through Digestibility Experiments. Univ. Georgia Press. Athens.
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