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Evaluation of Waste Activated Sludge (Citrus) as a Source of Xanthophyll Pigment for Laying Hens and Broilers1
Evaluation of Waste Activated Sludge (Citrus) as a Source of Xanthophyll Pigment for Laying Hens and Broilers1 D. M. JANKY, C. FRANCIS, B. L. DAMRON, and D. L. FLETCHER 2 Department of Poultry Science, University of Florida, Gainesville, Florida 32611 (Received for publication June 22, 1981)
1982 Poultry Science 61:468-477
INTRODUCTION
It has been generally accepted that the inclusion of xanthophyll-containing feedstuffs in the diet of laying hens and broilers is necessary for the production of normal appearance of egg yolks and broiler skin. The usual dietary sources of xanthophyll have been yellow corn and alfalfa meal; however, when a significantly greater degree of pigmentation has been desirable, as in egg yolks for noodle manufacture or very pigmented broilers for certain markets, the producer has turned to feedstuffs such as corn gluten meal and marigold petals for additional xanthophyll concentration. These feedstuffs have been relatively expensive for this purpose. Many pigmentation studies have been conducted using alternate xanthophyll sources which would be less expensive, since these sources would be considered by-products of another industry or could be produced more economically. Morgan and Woodroof (1927) and Brown (1938) observed that waste pimento peppers could be used to pigment egg yolks.
1 Florida Agricultural Experiment Stations Journal Series No. 3103. 2 Present address: Department of Poultry Science, University of Georgia, Athens, GA 30605.
Since all green plants contain xanthophyll, various researchers have fed plants such as seaweed (Jensen, 1963), lakeweed (Madiedo and Sunde, 1962), algae (Grau and Klein, 1957; Morehouse, 1961; Madiedo and Sunde, 1962; Nelson and Baptist, 1968), broccoli meal (Runnels et al, 1951), and kenaf tops (Fry et al., 1967). Feeding these types of materials resulted in some degree of pigmentation in egg yolks. Feeding such products as dried cow manure (Littlefield et al, 1973), anaerobic mud, lobster shells, and bacteria (Nelson and Baptist, 1968) has also resulted in pigmentation of egg yolks. Waste activated sludge (citrus) has been evaluated as a nutrient source for laying hens and broilers (Eldred et al, 1975) and found to increase pigmentation in egg yolks (Angalet et al., 1976). Waste activated sludge (citrus) is the resulting product from the treatment of citrus processing plant effluent. The purpose of this research was to determine the availability of waste activated sludge (citrus) xanthophyll to the laying hen and broilers and to determine its pigmenting efficiency in comparison to yellow corn. EXPERIMENTAL PROCEDURE Laying Hens. In each of two trials, conducted 90 days apart, 80 commercial-type
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ABSTRACT In each of two trials, Cobb color-sexed broilers and a commercial strain of White Leghorn hens were fed diets containing either waste activated sludge (citrus) or yellow corn as the pigment source. Diets were formulated to contain xanthophyll levels of .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg diet from either yellow corn or waste activated sludge (citrus). These xanthophyll levels were supplied by 2.5, 5.0, 7.5, and 10.0% citrus sludge, respectively. Broiler shanks and egg yolks were evaluated colorimetrically for pigmentation. The xanthophyll in citrus sludge was not deposited in either egg yolks or broiler shanks to the same extent as was the xanthophyll present in yellow corn at any of the dietary xanthophyll levels tested. In the broiler studies, it appeared that xanthophyll from citrus sludge was deposited in the shank skin only in extremely small amounts, while in the laying hen studies, there did appear to be sufficient deposition of citrus sludge xanthophyll to provide adequate pigmentation for table eggs. This was partly due to the "more red" xanthophylls from citrus sludge as compared to those obtained from yellow corn. (Key words: waste activated sludge (citrus), citrus, pigmentation, yolk color, shanks)
CITRUS SLUDGE AND PIGMENTATION
The data were analyzed using analysis of variance and standard error of the mean procedures with the Statistical Analysis Systems programs (Statistical Analysis System, 1972). Significant differences between treatment means were determined using Duncan's multiple range test (Steel and Torrie, 1960). Since there was a trial X treatment interaction, the data were analyzed and presented separately by trial. Broilers. In each of two trials conducted 90 days apart, 9 male and 9 female Cobb colorsexed chicks (day-old) were randomly distributed into 2.32 m 2 pens, providing a density of
.129 m 2 /bird. All birds were brooded (infrared) on peanut hull litter over concrete flooring. During the first 28 days, all birds were fed (ad libitum) a xanthophyll-free starter diet (Table 2). From 29 to 56 days of age, birds in two replicate pens were fed one of eight experimental finisher-type diets (ad libitum) (Table 2). These diets were formulated to contain the same xanthophyll levels from either yellow corn or citrus sludge that were fed to laying hens and previoiisly described. Bird weights were obtained at 29 and 56 days of age arid feed consumption monitored so that milligrams xanthophyll consumed per kilogram body weight could be calculated. Mortality was also monitored, but since it was negligible and not related to treatment, data are not presented. At 56 days of age, 5 males and 5 females from each pen were killed by cervical dislocation, and the right shank from each bird was removed at the hock. The shanks were chilled in ice-slush, drained, packaged in Cryovac® bags, and frozen (—18 C) for color analysis using the IDL Color Eye® as described by Fry et al. (1969). The Color Eye® values were changed to dominant wavelength (DWL) or hue, excitation purity (EP) or intensity, and luminosity (LUM) or brightness values using the computer program developed by Fry and Damron (1971). The data were analyzed as in the laying hen study previously described. Since there was a trial X treatment interaction, the data from each trial were analyzed and presented separately.
RESULTS AND DISCUSSION
Laying Hen (Trial I). Hen-day egg production averaged 70.7% for the 21-day experimental period and was quite variable; however, dietary xanthophyll intake per dozen eggs produced indicated that the birds ingested the same amount of xanthophyll pigment per dozen eggs at each dietary xanthophyll concentration when either citrus sludge or yellow corn was the pigment source except at the highest level of pigment in the diet (Table 3). At this high level, birds fed the diet containing citrus sludge consumed significantly more pigment per dozen eggs produced than birds fed the yellow corn diet containing the same xanthophyll concentration. The EP values, which have been used to estimate pigment concentration in the egg yolk, were significantly lower for eggs from hens fed citrus sludge than for eggs from
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White Leghorn hens (approximately 50 weeks of age) were fed a xanthophyll-free diet (Table 1) for 15 days to deplete all pigment from developing ova. Two replicate groups of five individually caged, pigment-depleted hens were fed (ad libitum) one of eight experimental diets (Table 1). Four of the experimental diets contained graded levels of citrus sludge (2.5, 5.0, 7.5, and 10.0%). These levels were chosen, since Eldred et al. (1975) had established that citrus sludge levels of less than 10% had no detrimental effect on laying hen performance or broiler growth. The xanthophyll content of the citrus sludge was analyzed at 37.4 mg/kg by the State Feed Laboratory (Division of Chemistry of the Florida Department of Agricultural and Consumer Services). Thus, the four citrus sludge diets (2.5, 5.0, 7.5, and 10.0% sludge) contained .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg of diet, respectively. The other four experimental diets contained yellow corn as the only source of xanthophyll and were formulated to contain .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg of diet. Hens were fed (ad libitum) the experimental diets for 21 days to insure maximum pigment deposition. Feed consumption and egg production were monitored during the 21-day experimental period to allow calculation of milligrams xanthophyll consumed per dozen eggs produced. Mortality was also monitored, but since it was negligible and not related to treatment, data are not presented. Following the 21-day experimental period, eggs were collected for 3 consecutive days from each pen, pooled, and analyzed, in duplicate, for yolk color (without dilution) using the IDL Color Eye® according to the procedure described by Fletcher et al. (1978). Egg yolks were also evaluated for color by a three-member panel with the Hoffman LaRoche Yolk Color Fan® used as a standard.
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37.35 32.67 19.00 6.88 2.25 .35 .50 1.00
70.02
19.00 6.88 2.25 .35 .50
1.00
Yellow corn
1.00
19.00 6.88 2.25 .35 .50
45.52 24.50
Yellow corn
7.50 16.77 6.78 2.42 .35 .50 1.88 .05 .50
\/o) 63.25
Citrus sludge (7.5%)
2.81 mg/kg
Supplied the following activities per kilogram of diet: 6,600 IU vitamin A, 2,200 ICU vitamin D 3 , 500 mg cholin pantothenic acid, 22 Mg vitamin B 1 2 , 125 mgethoxyquin, 20 mg zinc, 71 mg manganese, and 2.2 mg menadione sodium
Citrus sludge was analyzed to contain 22.4% protein, .45% phosphorus, 1.6% calcium, 800 kcal ME, and 37.4 mg xa
10.00 16.02 6.74 2.48 .35 .50 2.51 .07 .33
61.00
Citrus sludge (10%)
3.74 mg/kg
Pigment depletion diet fed for 15 days prior to the start of the experiment.
White corn Yellow corn Citrus sludgeb Soybean meal (50% protein) Limestone Dicalcium phosphate (18.5% P, 22.0% Ca) Iodized salt Microingredient mix c Animal fat DL-methionine Sand
Ingredient
Xanthophyllfree diet a
Dietary xanthophyll level
TABLE 1. Composition of layer diets formulated to contain equivalent graded levels of either yellow corn or citrus sludge (Trials 1 and 2)
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38.63 1.22 2.05 .40 .50 .09
2.12 .05
32.97
.40 .50 .11
1.17
.05
2.19
.99
31.53 23.41
61.62
Yellow corn
.05
4.94
.40 .50 .18
2.04
.67
10.00 35.46
45.76
Citrus sludge (10%)
3.74 mg/kg
.05
2.12
.40 .50 .09
38.63 1.22 2.05
37.39 17.55
Yellow corn
.05
4.24
.40 .50 .16
2.04
.80
7.50 36.25
48.06
Citrus sludge (7.5%)
2.81 mg/kg
Dietary xan thophyll level (m
Supplied the following activities per kilogram of diet: 6,600 IU vitamin A, 2,200 ICU vitamin D 3 , 2.2 mg menad vin, 13.2 mg pantothenic acid, 39.6 mg niacin, 499.4 mg choline chloride, 22 fig vitamin B 1 2 , .0125% ethoxyquin, 60 cobalt, 1.1 mg iodine, and 35 mg zinc.
Citrus sludge was analyzed to contain 22.4% protein, .45% phosphorus, 1.6% calcium, 800 kcal ME, and 37.4 mg xa
Fed from 29—56 days of age.
Fed from 1-28 days of age.
White corn Yellow corn Citrus sludge c Soybean meal (50% protein) Limestone Dicalcium phosphate (18.5% P, 22.0% Ca) Iodized salt Microingredient mixd DL-methionine Animal fat Amprol
Ingredient
Xanthophyllfree starter diet a
TABLE 2. Composition of broiler diets formulated to contain equivalent graded levels o either yellow corn or citrus sludge (Trials 1 and 2)
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JANKY ET AL.
472
citrus sludge than yolks from hens fed yellow corn. The DWL values, or actual color, of the egg yolks from hens fed citrus sludge or yellow corn at the same dietary xanthophyll level were not significantly different except at the lowest dietary level of xanthophyll (Table 4). At this level, yolks from hens fed the yellow corn diet were significantly more orange (higher DWL) than yolk from hens fed the citrus sludge diet. These data would intake, however, that the pigment in citrus sludge was a more orange hue than that provided by yellow corn, since less xanthophyll present (lower EP) from citrus sludge gave the same or higher DWL (hue) as yellow corn at all dietary xanthophyll concentrations. This was more clearly observed by comparing the DWL of yolks from hens fed yellow corn and the DWL of yolks from hens fed citrus sludge where EP (yolk xanthophyll concentration) was the same (Table 4). The EP value for yolks from hens fed the yellow corn diet at 1.87 mg xanthophyll per kilogram diet was statistically the same as the EP value of yolks from hens fed the citrus sludge diet at a dietary xanthophyll level of 3.74 mg/kg, indicating similar pigment concentration, but the DWL of the yolks from hens fed this citrus
TABLE 3. Calculated milligrams of xanthophyll consumed per dozen eggs produced3- for laying hens fed diets formulated to contain equivalent graded levels of xanthophyll from either yellow com or citrus sludge (Trials 1 and 2) Dietary pigment concentration
Pigment source Citrus sludge
Yellow corn (mg xanthophyll/doz eggs)
(mg xanthophyll/kg diet) Trial 1 .93 (2.5% sludge) 1.87 (5.0% sludge) 2.81 (7.5% sludge) 3.74 (10.0% sludge)
1.41 3.22 5.00 6.10
± .02 b + .04 ± .51 + .04
1.46 3.38 4.61 6.55
± .08 + .13 ± .08 ± .15*
Trial 2 .93 (2.5% sludge) 1.87 (5.0% sludge) 2.81 (7.5% sludge) 3.74 (10.0% sludge)
1.66 3.35 5.14 7.07
± .10 ± .21 ±.11 ± .41
1.64 3.93 5.45 6.99
± .02 ± .56 ± .28 + .49
Milligrams of xanthophyll consumed per dozen eggs produced were calculated from egg production and feed consumption data obtained over the 21 day experimental period. Standard error of the mean. *Mean for citrus sludge treatment is significantly different from the mean for the corresponding yellow corn diet (P<.05).
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hens fed yellow corn for each dietary xanthophyll level (Table 4). These data would indicate that even though consumption of xanthophyll per dozen eggs produced was the same, and, at one dietary xanthophyll level, significantly higher when citrus sludge was the pigment source, a significantly greater amount of xanthophyll from yellow corn was deposited in the egg yolk than that deposited from citrus sludge. This could have been due to any of several factors or combinations of factors: the xanthophylls in citrus sludge could have been more susceptible to oxidative deterioration than those in yellow corn; the xanthophyll component in citrus sludge may have included xanthophylls such as citranxanthin, which has a 50% vitamin A activity and thus is only 50% available as a pigmenting agent; or the xanthophylls in yellow corn may have been more biologically available than those in citrus sludge. As would be expected, as dietary xanthophyll concentration was increased, EP, or egg yolk xanthophyll concentration, also increased, regardless of xanthophyll source (Table 4). However, the plateau effect normally observed as dietary pigment concentration is increased (Fry and Harms, 1973) occurred at lower dietary xanthophyll levels in the egg yolks from hens fed the
4.0 b 5.3C 7.0 d 7.9 e
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge) 2.4 a 3.6 b 3.8 b 4.2b
1.7a 2.5 b 3.2 c d 3.7 d
Citrus sludge
573.4 b 574.0 C 574.9 d 575.3 e
573.5 b 574.2 c d 574. 4 de 574.9 f
Yellow corn
572.8* 573.5 b 574.0C 574.2 C
573.0* 573.9 C 574.6 e f 574.9 f
Citrus sludge
DWL (nm)
56.86 c 68.92 d 78.38 e 80.84 f
50.29 b c 62.01ef 66.43 f 73.358
Yellow corn
Co
h
Hoffman LaRoche Yolk Colour Fan®.
a,b,c,d,e,f Means within the same trial and measurement parameter followed by different small letters are significant
1.8a 3.0 b c 4.8ef 5.2 f
Yellow corn
Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
(mg xanthophyll/kg diet)
Dietary pigment concentration
Visual scores"
TABLE 4. Visual scores, dominant wavelength (DWL), excitation purity (EP), and luminosity from hens fed diets formulated to contain equivalent graded levels of xantho either yellow com or citrus sludge (Trials 1 and 2)
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474
JANKY ET AL.
The LUM and EP values followed the same general trends as seen in Trial 1, except that EP values overall were higher than those in Trial 1 while LUM values overall were lower (Table 4). This would be expected since milligrams xanthophyll consumed per dozen eggs was also higher than in Trial 1. The EP values increased even more dramatically for yolks from hens fed yellow corn as the pigment source as dietary xanthophyll level was increased in Trial 2; however, EP values for yolks from hens fed citrus sludge appeared to plateau at an even lower dietary xanthophyll level than was observed in Trial 1. This would account for the significant trial X treatment interaction. The storage of the citrus sludge for the extra 90
days which passed between trials might have allowed for further xanthophyll oxidation than had occurred in Trial 1. These data indicated that maximum deposition of xanthophyll from citrus sludge occurred at 7.5 to 10.0% citrus sludge in the diet. Visual scores for yolks from hens fed yellow corn were significantly higher than scores for yolks from hens fed citrus sludge at all comparable xanthophyll levels. This was the result of the increased EP values observed in this trial and previously discussed. The DWL values were significantly higher (more orange) for yolks from hens fed yellow corn than values obtained for yolks from hens fed citrus sludge at all comparable dietary xanthophyll levels (Table 4). This was due to the much higher pigment concentration in yolks from hens fed yellow corn. A comparison, as in Trial 1, of yolks from hens fed the two pigment sources with the same EP showed a significantly higher DWL (more orange) for yolks from hens fed citrus sludge as the pigment source. The data from the two trials indicated that citrus sludge could be used as a pigment source for egg yolks; however, it would appear that its use should be limited to the production of table eggs where only moderate to light pigmentation is required. For egg yolks used as the colorant in a further processed product such as egg noodles, citrus sludge would not be able to supply a sufficient concentration of xanthophyll in the yolk at reasonable levels of sludge in the diet of the hen. Broilers (Trial 1). Average weight gain (males and females combined) was 1074 g for the 28-day experimental period. Calculated values for milligrams xanthophyll consumed per kilogram body weight (from 29 to 56 days of age) were significantly higher for birds fed citrus sludge except at the lowest xanthophyll level in the diet (Table 5). Shank EP (pigment concentration) (Table 6), however, was significantly higher for birds receiving yellow corn as the pigment source at all dietary levels of xanthophyll. A significant increase in shank EP was also observed as dietary xanthophyll level was increased when yellow corn was the pigment source; however, there was no difference in EP of shanks from birds fed the citrus sludge pigment source as dietary xanthophyll level was increased (Table 6). These data indicated that only a very small amount of pigment, if any, was deposited into the skin from the citrus
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sludge diet was significantly more orange (higher) than the DWL for yolks from hens fed the yellow corn diet at the lower xanthophyll level. As expected, increasing the level of xanthophyll in the diet increased DWL, regardless of the pigment source fed (Table 4). The LUM values (brightness) tended to decrease as dietary pigment concentration was increased [more pigment (higher EP) equals darker color] ; however, there was no difference in LUM values for yolks from hens fed diets containing citrus sludge and yolks from hens fed yellow corn at the same dietary xanthophyll level (Table 4). Hoffman LaRoche Yolk Colour Fan® visual scores were significantly higher for yolks from hens fed yellow corn as a pigment source than yolks from hens fed citrus sludge at the two higher dietary xanthophyll levels (Table 4). At the two low dietary xanthophyll levels, there were no significant differences in visual scores for yolks from hens fed citrus sludge or yellow corn as the pigment source. These differences can be explained by the differences in EP (yolk xanthophyll concentration), since this portion of the Hoffman LaRoche Yolk Colour Fan® is more sensitive to EP changes than DWL changes (Fletcher et al, 1978). Laying Hens (Trial 2). Calculated dietary xanthophyll intake per dozen eggs produced was slightly higher compared to values obtained in Trial 1, due to a lower average henday egg production level of 65.0%, but was not significantly different between birds fed citrus sludge and birds fed yellow corn at any of the dietary xanthophyll levels tested (Table 3).
CITRUS SLUDGE AND PIGMENTATION
Shank LUM values did not significantly change as the dietary level of xanthophyll from either source was increased (Table 6). Also, there was no significant difference in LUM values of shanks from birds fed citrus sludge at any dietary xanthophyll level except 1.87 mg xanthophyll/kg diet (Table 6). At this level
of dietary xanthophyll, feeding citrus sludge produced significantly darker (lower LUM) shanks than did yellow corn. Broilers (Trial 2). Average weight gain (males and females combined) over the 28-day experimental period was 1301 g. Calculated values for milligrams xandiophyll consumed per kilogram body weight gain (29 to 56 days) for broilers fed either citrus sludge or yellow corn were not significantly different at any dietary xanthophyll level tested (Table 5). Shank EP values, however, from birds fed yellow corn increased significandy at each dietary xanthophyll level increase and were significantly higher than EP values for shanks from birds fed citrus sludge at comparable dietary xanthophyll levels (Table 6). Unlike Trial 1, shank EP values from birds fed citrus sludge did appear to increase slightly as dietary xanthophyll level was increased (Table 6). This would account for the significant treatment X trial interaction observed; however, since the significant differences observed in Trial 2 were so small, it was concluded that there was essentially no difference in xandiophyll deposition in broiler shanks between the two trials. As in Trial 1, shank DWL values were significandy lower for birds fed yellow corn than for
TABLE 5. Calculated milligrams of xanthophyll consumed per kilogram body weight3- for broilers (29 to 56 days of age) fed diets formulated to contain equivalent graded levels of xanthophyll from either yellow corn or citrus sludge (Trial?. 1 and 2) Dietary pigment concentration
Pigment source Yellow corn
Citrus sludge
(mg xanthophyll/kg body weight)
(mg xanthophyll/kg diet) Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
2.49 4.86 7.31 9.57
± ± ± ±
.08b .11 .14 .11
2.42 5.11 7.76 9.84
± .04 ± .07* ± .17* ± .07*
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
1.98 3.63 5.42 7.63
± ± ± ±
.08 .04 .03 .30
1.87 3.67 5.09 7.37
± ± ± ±
.15 .07 .53 .37
Milligrams of xanthophyll consumed per kilogram of body weight were calculated from feed consumption and body weight gain data obtained during the 29 to 56 day growth period. Standard error of the mean. *Mean for citrus sludge treatment is significantly different from tlie mean for the corresponding yellow corn diet(P<.05).
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sludge in the diet. This could have been due to the same reasons previously discussed for the lack of citrus sludge pigment deposition in the egg yolk. Shank DWL values were significantly lower from birds fed yellow corn than from birds fed citrus sludge, regardless of dietary xanthophyll level. This would indicate that shanks from birds fed citrus sludge were more red than those from birds fed yellow corn at the same dietary xanthophyll level. The high DWL values for shanks from broilers fed the citrus sludge diet appeared to result from a lack of pigment deposition (low EP), since color values obtained for these shanks were very similar to those which have been obtained for shanks from birds fed a xanthophyll-free diet (Francis, 1980, unpublished data). As pigment concentration in die diet was increased, there was essentially no change in DWL or shanks from birds fed either citrus sludge or yellow corn (Table 6).
475
578.0* 578.6b 578.3 ab 578.5 ab
578.6 bc 578.8cd 578.3 ab 577.9a
Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge) 579.4 e f
579.6f 579 2def 579,0cde
579.5 cd 579.8d 579.lc 579.6d
Citrus sludge
24.00c 27.58 d 31.79e 34.52f
24.11° 26.93c 31.33 d 34.74e
Yellow corn
EP (%)
Color values
20.8 22.5 22.6 23.5
22.3 23.2 22.0 22.6
Citru sludg
Means within a parameter and trial followed by different small letters are significantly different (P<.05).
(mg xanthophyll/kg diet)
Yellow corn
Dietary pigment concentration
DWL (nm)
TABLE 6. Dominant wavelength (DWL), excitation purity (EP)y and luminosity (LUM) for shank sa (29 to 56 days of age) formulated to contain equivalent graded levels of xanthop either yellow com or citrus sludge (Trial 1 and 2)
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CITRUS SLUDGE AND PIGMENTATION
ACKNOWLEDGMENT This research was supported by a grant (R-803997) from the Environmental Protection Agency, Food and Wood Products Branch, Industrial Environmental Research Laboratory, Cincinnati, OH 45268. The assistance of Harold Thompson, Project Officer, EPA, with equipment procurement, sludge dewatering, and the entire engineering phase of the study was a key factor in the project and deserves commendation. The cooperation of Citrus World, Inc., Lake Wales, Florida, and its Director of Research, M. W. Ratcliff, in providing the sludge, facilities, and technical and laboratory help is greatly appreciated. REFERENCES Angalet, S. A., J. L. Fry, B. L. Damron, and R. H. Harms, 1976. Evaluation of waste activated sludge (citrus) as a poultry feed ingredient. Poultry Sci. 55:1219-1225. Brown, W. L., 1938. The influence of pigments on the color of the egg yolks of fowls. J. Biol. Chem. 122:655-659. Eldred, A., B. L. Damron, and R. H. Harms, 1975. Evaluation of waste activated sludge (citrus) as a poultry feed ingredient. 1. Performance of
chicks, broilers, and laying hens. Nutr. Rep. Int. 14(2):139-145. Fletcher, D. L., R. H. Harms, and D. M. Janky, 1978. Yolk color characteristics, xanthophyll availability and a model system for predicting egg yolk color using 0-apo-8'-carotenal and canthaxanthin. Poultry Sci. 57:624-629. Fry, J. L., E. M. Ahmed, G. M. Herrick, and R. H. Harms, 1969. A reflectance method of determining skin and shank pigmentation. Poultry Sci. 48:1127-1129. Fry, J. L., and B. L. Damron, 1971. Computer calculation of poultry and egg pigmentation data. FoodTechnol. 2 5 : 4 4 - 4 5 . Fry, J. L., and R. H. Harms, 1975. Yolk color, candled egg grade and xanthophyll availability from dietary natural pigmenting ingredients. Poultry Sci. 54:1094-1101. Fry, J. L., G. M. Herrick, and R. H. Harms, 1967. Yolk pigmenting value of dried kenaf tops. Q. J. Florida Acad. Sci. 3O(4):295-30O. Grau, C. R., and N. W. Klein, 1957. Sewage-grown algae as a feedstuff for chicks. Poultry Sci. 36: 1046-1051. Jensen, A., 1963. The effect of seaweed carotenoids on egg yolk coloration. Poultry Sci. 4 2 : 9 1 2 916. Littlefield, L. H., J. K. Bietner, and O. E. Goff, 1973. The effect of feeding laying hens various levels of cow manure on the pigmentation of egg yolks. Poultry Sci. 5 2 : 1 7 9 - 1 8 1 . Madiedo, C , and M. L. Sunde, 1962. The effect of algae, dried lakeweed, alfalfa meal, and ethoxyquin on yolk color. Poultry Sci. 41:1660. (Abstr.) Morehouse, A. L., 1961. Dried algae meal as a source of xanthophyll for egg yolk pigmentation. Poultry Sci. 40:1432. Morgan, W. A., and J. G. Woodroof, 1927. Waste pimento pepper for color in egg yolks. Georgia Exp. Sta. Bull. 147. Nelson, T. S., and J. N. Baptist, 1968. Feed pigments. 2. The influence of feeding single and combined sources of red and yellow pigment on egg yolk color. Poultry Sci. 4 7 : 9 2 4 - 9 3 1 . Runnels, T. D., E. F. Waller, E. G. Kelly, and S. Krulick, 1951. Growth promotion and pigmentation properties of dehydrated broccoli leaf meal in a practical broiler diet. Poultry Sci. 30: 930. (Abstr.) Statistical Analysis System, 1972. A user's guide to the statistical analysis system. SAS Inst., Raleigh, NC. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, NY.
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birds fed citrus sludge at all dietary xanthophyll levels tested (Table 6). In this trial, however, shank DWL for birds fed yellow corn appeared to decfease as dietary xanthophyll level was increased (Table 6). This was expected, since the addition of yellow pigment from yellow corn should overshadow the color of a completely pigment-free shank. There were no significant differences in shank LUM values as dietary xanthophyll level was increased or between dietary pigment sources (Table 6). From the data obtained in Trials 1 and 2 with broilers, it was concluded that the xanthophyll component of citrus sludge was not deposited at an efficient level in broiler skin, regardless of the level fed.
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1982 Poultry Science 61:468-477
INTRODUCTION
It has been generally accepted that the inclusion of xanthophyll-containing feedstuffs in the diet of laying hens and broilers is necessary for the production of normal appearance of egg yolks and broiler skin. The usual dietary sources of xanthophyll have been yellow corn and alfalfa meal; however, when a significantly greater degree of pigmentation has been desirable, as in egg yolks for noodle manufacture or very pigmented broilers for certain markets, the producer has turned to feedstuffs such as corn gluten meal and marigold petals for additional xanthophyll concentration. These feedstuffs have been relatively expensive for this purpose. Many pigmentation studies have been conducted using alternate xanthophyll sources which would be less expensive, since these sources would be considered by-products of another industry or could be produced more economically. Morgan and Woodroof (1927) and Brown (1938) observed that waste pimento peppers could be used to pigment egg yolks.
1 Florida Agricultural Experiment Stations Journal Series No. 3103. 2 Present address: Department of Poultry Science, University of Georgia, Athens, GA 30605.
Since all green plants contain xanthophyll, various researchers have fed plants such as seaweed (Jensen, 1963), lakeweed (Madiedo and Sunde, 1962), algae (Grau and Klein, 1957; Morehouse, 1961; Madiedo and Sunde, 1962; Nelson and Baptist, 1968), broccoli meal (Runnels et al, 1951), and kenaf tops (Fry et al., 1967). Feeding these types of materials resulted in some degree of pigmentation in egg yolks. Feeding such products as dried cow manure (Littlefield et al, 1973), anaerobic mud, lobster shells, and bacteria (Nelson and Baptist, 1968) has also resulted in pigmentation of egg yolks. Waste activated sludge (citrus) has been evaluated as a nutrient source for laying hens and broilers (Eldred et al, 1975) and found to increase pigmentation in egg yolks (Angalet et al., 1976). Waste activated sludge (citrus) is the resulting product from the treatment of citrus processing plant effluent. The purpose of this research was to determine the availability of waste activated sludge (citrus) xanthophyll to the laying hen and broilers and to determine its pigmenting efficiency in comparison to yellow corn. EXPERIMENTAL PROCEDURE Laying Hens. In each of two trials, conducted 90 days apart, 80 commercial-type
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ABSTRACT In each of two trials, Cobb color-sexed broilers and a commercial strain of White Leghorn hens were fed diets containing either waste activated sludge (citrus) or yellow corn as the pigment source. Diets were formulated to contain xanthophyll levels of .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg diet from either yellow corn or waste activated sludge (citrus). These xanthophyll levels were supplied by 2.5, 5.0, 7.5, and 10.0% citrus sludge, respectively. Broiler shanks and egg yolks were evaluated colorimetrically for pigmentation. The xanthophyll in citrus sludge was not deposited in either egg yolks or broiler shanks to the same extent as was the xanthophyll present in yellow corn at any of the dietary xanthophyll levels tested. In the broiler studies, it appeared that xanthophyll from citrus sludge was deposited in the shank skin only in extremely small amounts, while in the laying hen studies, there did appear to be sufficient deposition of citrus sludge xanthophyll to provide adequate pigmentation for table eggs. This was partly due to the "more red" xanthophylls from citrus sludge as compared to those obtained from yellow corn. (Key words: waste activated sludge (citrus), citrus, pigmentation, yolk color, shanks)
CITRUS SLUDGE AND PIGMENTATION
The data were analyzed using analysis of variance and standard error of the mean procedures with the Statistical Analysis Systems programs (Statistical Analysis System, 1972). Significant differences between treatment means were determined using Duncan's multiple range test (Steel and Torrie, 1960). Since there was a trial X treatment interaction, the data were analyzed and presented separately by trial. Broilers. In each of two trials conducted 90 days apart, 9 male and 9 female Cobb colorsexed chicks (day-old) were randomly distributed into 2.32 m 2 pens, providing a density of
.129 m 2 /bird. All birds were brooded (infrared) on peanut hull litter over concrete flooring. During the first 28 days, all birds were fed (ad libitum) a xanthophyll-free starter diet (Table 2). From 29 to 56 days of age, birds in two replicate pens were fed one of eight experimental finisher-type diets (ad libitum) (Table 2). These diets were formulated to contain the same xanthophyll levels from either yellow corn or citrus sludge that were fed to laying hens and previoiisly described. Bird weights were obtained at 29 and 56 days of age arid feed consumption monitored so that milligrams xanthophyll consumed per kilogram body weight could be calculated. Mortality was also monitored, but since it was negligible and not related to treatment, data are not presented. At 56 days of age, 5 males and 5 females from each pen were killed by cervical dislocation, and the right shank from each bird was removed at the hock. The shanks were chilled in ice-slush, drained, packaged in Cryovac® bags, and frozen (—18 C) for color analysis using the IDL Color Eye® as described by Fry et al. (1969). The Color Eye® values were changed to dominant wavelength (DWL) or hue, excitation purity (EP) or intensity, and luminosity (LUM) or brightness values using the computer program developed by Fry and Damron (1971). The data were analyzed as in the laying hen study previously described. Since there was a trial X treatment interaction, the data from each trial were analyzed and presented separately.
RESULTS AND DISCUSSION
Laying Hen (Trial I). Hen-day egg production averaged 70.7% for the 21-day experimental period and was quite variable; however, dietary xanthophyll intake per dozen eggs produced indicated that the birds ingested the same amount of xanthophyll pigment per dozen eggs at each dietary xanthophyll concentration when either citrus sludge or yellow corn was the pigment source except at the highest level of pigment in the diet (Table 3). At this high level, birds fed the diet containing citrus sludge consumed significantly more pigment per dozen eggs produced than birds fed the yellow corn diet containing the same xanthophyll concentration. The EP values, which have been used to estimate pigment concentration in the egg yolk, were significantly lower for eggs from hens fed citrus sludge than for eggs from
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White Leghorn hens (approximately 50 weeks of age) were fed a xanthophyll-free diet (Table 1) for 15 days to deplete all pigment from developing ova. Two replicate groups of five individually caged, pigment-depleted hens were fed (ad libitum) one of eight experimental diets (Table 1). Four of the experimental diets contained graded levels of citrus sludge (2.5, 5.0, 7.5, and 10.0%). These levels were chosen, since Eldred et al. (1975) had established that citrus sludge levels of less than 10% had no detrimental effect on laying hen performance or broiler growth. The xanthophyll content of the citrus sludge was analyzed at 37.4 mg/kg by the State Feed Laboratory (Division of Chemistry of the Florida Department of Agricultural and Consumer Services). Thus, the four citrus sludge diets (2.5, 5.0, 7.5, and 10.0% sludge) contained .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg of diet, respectively. The other four experimental diets contained yellow corn as the only source of xanthophyll and were formulated to contain .93, 1.87, 2.81, and 3.74 mg xanthophyll/kg of diet. Hens were fed (ad libitum) the experimental diets for 21 days to insure maximum pigment deposition. Feed consumption and egg production were monitored during the 21-day experimental period to allow calculation of milligrams xanthophyll consumed per dozen eggs produced. Mortality was also monitored, but since it was negligible and not related to treatment, data are not presented. Following the 21-day experimental period, eggs were collected for 3 consecutive days from each pen, pooled, and analyzed, in duplicate, for yolk color (without dilution) using the IDL Color Eye® according to the procedure described by Fletcher et al. (1978). Egg yolks were also evaluated for color by a three-member panel with the Hoffman LaRoche Yolk Color Fan® used as a standard.
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37.35 32.67 19.00 6.88 2.25 .35 .50 1.00
70.02
19.00 6.88 2.25 .35 .50
1.00
Yellow corn
1.00
19.00 6.88 2.25 .35 .50
45.52 24.50
Yellow corn
7.50 16.77 6.78 2.42 .35 .50 1.88 .05 .50
\/o) 63.25
Citrus sludge (7.5%)
2.81 mg/kg
Supplied the following activities per kilogram of diet: 6,600 IU vitamin A, 2,200 ICU vitamin D 3 , 500 mg cholin pantothenic acid, 22 Mg vitamin B 1 2 , 125 mgethoxyquin, 20 mg zinc, 71 mg manganese, and 2.2 mg menadione sodium
Citrus sludge was analyzed to contain 22.4% protein, .45% phosphorus, 1.6% calcium, 800 kcal ME, and 37.4 mg xa
10.00 16.02 6.74 2.48 .35 .50 2.51 .07 .33
61.00
Citrus sludge (10%)
3.74 mg/kg
Pigment depletion diet fed for 15 days prior to the start of the experiment.
White corn Yellow corn Citrus sludgeb Soybean meal (50% protein) Limestone Dicalcium phosphate (18.5% P, 22.0% Ca) Iodized salt Microingredient mix c Animal fat DL-methionine Sand
Ingredient
Xanthophyllfree diet a
Dietary xanthophyll level
TABLE 1. Composition of layer diets formulated to contain equivalent graded levels of either yellow corn or citrus sludge (Trials 1 and 2)
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38.63 1.22 2.05 .40 .50 .09
2.12 .05
32.97
.40 .50 .11
1.17
.05
2.19
.99
31.53 23.41
61.62
Yellow corn
.05
4.94
.40 .50 .18
2.04
.67
10.00 35.46
45.76
Citrus sludge (10%)
3.74 mg/kg
.05
2.12
.40 .50 .09
38.63 1.22 2.05
37.39 17.55
Yellow corn
.05
4.24
.40 .50 .16
2.04
.80
7.50 36.25
48.06
Citrus sludge (7.5%)
2.81 mg/kg
Dietary xan thophyll level (m
Supplied the following activities per kilogram of diet: 6,600 IU vitamin A, 2,200 ICU vitamin D 3 , 2.2 mg menad vin, 13.2 mg pantothenic acid, 39.6 mg niacin, 499.4 mg choline chloride, 22 fig vitamin B 1 2 , .0125% ethoxyquin, 60 cobalt, 1.1 mg iodine, and 35 mg zinc.
Citrus sludge was analyzed to contain 22.4% protein, .45% phosphorus, 1.6% calcium, 800 kcal ME, and 37.4 mg xa
Fed from 29—56 days of age.
Fed from 1-28 days of age.
White corn Yellow corn Citrus sludge c Soybean meal (50% protein) Limestone Dicalcium phosphate (18.5% P, 22.0% Ca) Iodized salt Microingredient mixd DL-methionine Animal fat Amprol
Ingredient
Xanthophyllfree starter diet a
TABLE 2. Composition of broiler diets formulated to contain equivalent graded levels o either yellow corn or citrus sludge (Trials 1 and 2)
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JANKY ET AL.
472
citrus sludge than yolks from hens fed yellow corn. The DWL values, or actual color, of the egg yolks from hens fed citrus sludge or yellow corn at the same dietary xanthophyll level were not significantly different except at the lowest dietary level of xanthophyll (Table 4). At this level, yolks from hens fed the yellow corn diet were significantly more orange (higher DWL) than yolk from hens fed the citrus sludge diet. These data would intake, however, that the pigment in citrus sludge was a more orange hue than that provided by yellow corn, since less xanthophyll present (lower EP) from citrus sludge gave the same or higher DWL (hue) as yellow corn at all dietary xanthophyll concentrations. This was more clearly observed by comparing the DWL of yolks from hens fed yellow corn and the DWL of yolks from hens fed citrus sludge where EP (yolk xanthophyll concentration) was the same (Table 4). The EP value for yolks from hens fed the yellow corn diet at 1.87 mg xanthophyll per kilogram diet was statistically the same as the EP value of yolks from hens fed the citrus sludge diet at a dietary xanthophyll level of 3.74 mg/kg, indicating similar pigment concentration, but the DWL of the yolks from hens fed this citrus
TABLE 3. Calculated milligrams of xanthophyll consumed per dozen eggs produced3- for laying hens fed diets formulated to contain equivalent graded levels of xanthophyll from either yellow com or citrus sludge (Trials 1 and 2) Dietary pigment concentration
Pigment source Citrus sludge
Yellow corn (mg xanthophyll/doz eggs)
(mg xanthophyll/kg diet) Trial 1 .93 (2.5% sludge) 1.87 (5.0% sludge) 2.81 (7.5% sludge) 3.74 (10.0% sludge)
1.41 3.22 5.00 6.10
± .02 b + .04 ± .51 + .04
1.46 3.38 4.61 6.55
± .08 + .13 ± .08 ± .15*
Trial 2 .93 (2.5% sludge) 1.87 (5.0% sludge) 2.81 (7.5% sludge) 3.74 (10.0% sludge)
1.66 3.35 5.14 7.07
± .10 ± .21 ±.11 ± .41
1.64 3.93 5.45 6.99
± .02 ± .56 ± .28 + .49
Milligrams of xanthophyll consumed per dozen eggs produced were calculated from egg production and feed consumption data obtained over the 21 day experimental period. Standard error of the mean. *Mean for citrus sludge treatment is significantly different from the mean for the corresponding yellow corn diet (P<.05).
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hens fed yellow corn for each dietary xanthophyll level (Table 4). These data would indicate that even though consumption of xanthophyll per dozen eggs produced was the same, and, at one dietary xanthophyll level, significantly higher when citrus sludge was the pigment source, a significantly greater amount of xanthophyll from yellow corn was deposited in the egg yolk than that deposited from citrus sludge. This could have been due to any of several factors or combinations of factors: the xanthophylls in citrus sludge could have been more susceptible to oxidative deterioration than those in yellow corn; the xanthophyll component in citrus sludge may have included xanthophylls such as citranxanthin, which has a 50% vitamin A activity and thus is only 50% available as a pigmenting agent; or the xanthophylls in yellow corn may have been more biologically available than those in citrus sludge. As would be expected, as dietary xanthophyll concentration was increased, EP, or egg yolk xanthophyll concentration, also increased, regardless of xanthophyll source (Table 4). However, the plateau effect normally observed as dietary pigment concentration is increased (Fry and Harms, 1973) occurred at lower dietary xanthophyll levels in the egg yolks from hens fed the
4.0 b 5.3C 7.0 d 7.9 e
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge) 2.4 a 3.6 b 3.8 b 4.2b
1.7a 2.5 b 3.2 c d 3.7 d
Citrus sludge
573.4 b 574.0 C 574.9 d 575.3 e
573.5 b 574.2 c d 574. 4 de 574.9 f
Yellow corn
572.8* 573.5 b 574.0C 574.2 C
573.0* 573.9 C 574.6 e f 574.9 f
Citrus sludge
DWL (nm)
56.86 c 68.92 d 78.38 e 80.84 f
50.29 b c 62.01ef 66.43 f 73.358
Yellow corn
Co
h
Hoffman LaRoche Yolk Colour Fan®.
a,b,c,d,e,f Means within the same trial and measurement parameter followed by different small letters are significant
1.8a 3.0 b c 4.8ef 5.2 f
Yellow corn
Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
(mg xanthophyll/kg diet)
Dietary pigment concentration
Visual scores"
TABLE 4. Visual scores, dominant wavelength (DWL), excitation purity (EP), and luminosity from hens fed diets formulated to contain equivalent graded levels of xantho either yellow com or citrus sludge (Trials 1 and 2)
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JANKY ET AL.
The LUM and EP values followed the same general trends as seen in Trial 1, except that EP values overall were higher than those in Trial 1 while LUM values overall were lower (Table 4). This would be expected since milligrams xanthophyll consumed per dozen eggs was also higher than in Trial 1. The EP values increased even more dramatically for yolks from hens fed yellow corn as the pigment source as dietary xanthophyll level was increased in Trial 2; however, EP values for yolks from hens fed citrus sludge appeared to plateau at an even lower dietary xanthophyll level than was observed in Trial 1. This would account for the significant trial X treatment interaction. The storage of the citrus sludge for the extra 90
days which passed between trials might have allowed for further xanthophyll oxidation than had occurred in Trial 1. These data indicated that maximum deposition of xanthophyll from citrus sludge occurred at 7.5 to 10.0% citrus sludge in the diet. Visual scores for yolks from hens fed yellow corn were significantly higher than scores for yolks from hens fed citrus sludge at all comparable xanthophyll levels. This was the result of the increased EP values observed in this trial and previously discussed. The DWL values were significantly higher (more orange) for yolks from hens fed yellow corn than values obtained for yolks from hens fed citrus sludge at all comparable dietary xanthophyll levels (Table 4). This was due to the much higher pigment concentration in yolks from hens fed yellow corn. A comparison, as in Trial 1, of yolks from hens fed the two pigment sources with the same EP showed a significantly higher DWL (more orange) for yolks from hens fed citrus sludge as the pigment source. The data from the two trials indicated that citrus sludge could be used as a pigment source for egg yolks; however, it would appear that its use should be limited to the production of table eggs where only moderate to light pigmentation is required. For egg yolks used as the colorant in a further processed product such as egg noodles, citrus sludge would not be able to supply a sufficient concentration of xanthophyll in the yolk at reasonable levels of sludge in the diet of the hen. Broilers (Trial 1). Average weight gain (males and females combined) was 1074 g for the 28-day experimental period. Calculated values for milligrams xanthophyll consumed per kilogram body weight (from 29 to 56 days of age) were significantly higher for birds fed citrus sludge except at the lowest xanthophyll level in the diet (Table 5). Shank EP (pigment concentration) (Table 6), however, was significantly higher for birds receiving yellow corn as the pigment source at all dietary levels of xanthophyll. A significant increase in shank EP was also observed as dietary xanthophyll level was increased when yellow corn was the pigment source; however, there was no difference in EP of shanks from birds fed the citrus sludge pigment source as dietary xanthophyll level was increased (Table 6). These data indicated that only a very small amount of pigment, if any, was deposited into the skin from the citrus
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sludge diet was significantly more orange (higher) than the DWL for yolks from hens fed the yellow corn diet at the lower xanthophyll level. As expected, increasing the level of xanthophyll in the diet increased DWL, regardless of the pigment source fed (Table 4). The LUM values (brightness) tended to decrease as dietary pigment concentration was increased [more pigment (higher EP) equals darker color] ; however, there was no difference in LUM values for yolks from hens fed diets containing citrus sludge and yolks from hens fed yellow corn at the same dietary xanthophyll level (Table 4). Hoffman LaRoche Yolk Colour Fan® visual scores were significantly higher for yolks from hens fed yellow corn as a pigment source than yolks from hens fed citrus sludge at the two higher dietary xanthophyll levels (Table 4). At the two low dietary xanthophyll levels, there were no significant differences in visual scores for yolks from hens fed citrus sludge or yellow corn as the pigment source. These differences can be explained by the differences in EP (yolk xanthophyll concentration), since this portion of the Hoffman LaRoche Yolk Colour Fan® is more sensitive to EP changes than DWL changes (Fletcher et al, 1978). Laying Hens (Trial 2). Calculated dietary xanthophyll intake per dozen eggs produced was slightly higher compared to values obtained in Trial 1, due to a lower average henday egg production level of 65.0%, but was not significantly different between birds fed citrus sludge and birds fed yellow corn at any of the dietary xanthophyll levels tested (Table 3).
CITRUS SLUDGE AND PIGMENTATION
Shank LUM values did not significantly change as the dietary level of xanthophyll from either source was increased (Table 6). Also, there was no significant difference in LUM values of shanks from birds fed citrus sludge at any dietary xanthophyll level except 1.87 mg xanthophyll/kg diet (Table 6). At this level
of dietary xanthophyll, feeding citrus sludge produced significantly darker (lower LUM) shanks than did yellow corn. Broilers (Trial 2). Average weight gain (males and females combined) over the 28-day experimental period was 1301 g. Calculated values for milligrams xandiophyll consumed per kilogram body weight gain (29 to 56 days) for broilers fed either citrus sludge or yellow corn were not significantly different at any dietary xanthophyll level tested (Table 5). Shank EP values, however, from birds fed yellow corn increased significandy at each dietary xanthophyll level increase and were significantly higher than EP values for shanks from birds fed citrus sludge at comparable dietary xanthophyll levels (Table 6). Unlike Trial 1, shank EP values from birds fed citrus sludge did appear to increase slightly as dietary xanthophyll level was increased (Table 6). This would account for the significant treatment X trial interaction observed; however, since the significant differences observed in Trial 2 were so small, it was concluded that there was essentially no difference in xandiophyll deposition in broiler shanks between the two trials. As in Trial 1, shank DWL values were significandy lower for birds fed yellow corn than for
TABLE 5. Calculated milligrams of xanthophyll consumed per kilogram body weight3- for broilers (29 to 56 days of age) fed diets formulated to contain equivalent graded levels of xanthophyll from either yellow corn or citrus sludge (Trial?. 1 and 2) Dietary pigment concentration
Pigment source Yellow corn
Citrus sludge
(mg xanthophyll/kg body weight)
(mg xanthophyll/kg diet) Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
2.49 4.86 7.31 9.57
± ± ± ±
.08b .11 .14 .11
2.42 5.11 7.76 9.84
± .04 ± .07* ± .17* ± .07*
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
1.98 3.63 5.42 7.63
± ± ± ±
.08 .04 .03 .30
1.87 3.67 5.09 7.37
± ± ± ±
.15 .07 .53 .37
Milligrams of xanthophyll consumed per kilogram of body weight were calculated from feed consumption and body weight gain data obtained during the 29 to 56 day growth period. Standard error of the mean. *Mean for citrus sludge treatment is significantly different from tlie mean for the corresponding yellow corn diet(P<.05).
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sludge in the diet. This could have been due to the same reasons previously discussed for the lack of citrus sludge pigment deposition in the egg yolk. Shank DWL values were significantly lower from birds fed yellow corn than from birds fed citrus sludge, regardless of dietary xanthophyll level. This would indicate that shanks from birds fed citrus sludge were more red than those from birds fed yellow corn at the same dietary xanthophyll level. The high DWL values for shanks from broilers fed the citrus sludge diet appeared to result from a lack of pigment deposition (low EP), since color values obtained for these shanks were very similar to those which have been obtained for shanks from birds fed a xanthophyll-free diet (Francis, 1980, unpublished data). As pigment concentration in die diet was increased, there was essentially no change in DWL or shanks from birds fed either citrus sludge or yellow corn (Table 6).
475
578.0* 578.6b 578.3 ab 578.5 ab
578.6 bc 578.8cd 578.3 ab 577.9a
Trial 1 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge)
Trial 2 .93 (2.5% citrus sludge) 1.87 (5.0% citrus sludge) 2.81 (7.5% citrus sludge) 3.74 (10.0% citrus sludge) 579.4 e f
579.6f 579 2def 579,0cde
579.5 cd 579.8d 579.lc 579.6d
Citrus sludge
24.00c 27.58 d 31.79e 34.52f
24.11° 26.93c 31.33 d 34.74e
Yellow corn
EP (%)
Color values
20.8 22.5 22.6 23.5
22.3 23.2 22.0 22.6
Citru sludg
Means within a parameter and trial followed by different small letters are significantly different (P<.05).
(mg xanthophyll/kg diet)
Yellow corn
Dietary pigment concentration
DWL (nm)
TABLE 6. Dominant wavelength (DWL), excitation purity (EP)y and luminosity (LUM) for shank sa (29 to 56 days of age) formulated to contain equivalent graded levels of xanthop either yellow com or citrus sludge (Trial 1 and 2)
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CITRUS SLUDGE AND PIGMENTATION
ACKNOWLEDGMENT This research was supported by a grant (R-803997) from the Environmental Protection Agency, Food and Wood Products Branch, Industrial Environmental Research Laboratory, Cincinnati, OH 45268. The assistance of Harold Thompson, Project Officer, EPA, with equipment procurement, sludge dewatering, and the entire engineering phase of the study was a key factor in the project and deserves commendation. The cooperation of Citrus World, Inc., Lake Wales, Florida, and its Director of Research, M. W. Ratcliff, in providing the sludge, facilities, and technical and laboratory help is greatly appreciated. REFERENCES Angalet, S. A., J. L. Fry, B. L. Damron, and R. H. Harms, 1976. Evaluation of waste activated sludge (citrus) as a poultry feed ingredient. Poultry Sci. 55:1219-1225. Brown, W. L., 1938. The influence of pigments on the color of the egg yolks of fowls. J. Biol. Chem. 122:655-659. Eldred, A., B. L. Damron, and R. H. Harms, 1975. Evaluation of waste activated sludge (citrus) as a poultry feed ingredient. 1. Performance of
chicks, broilers, and laying hens. Nutr. Rep. Int. 14(2):139-145. Fletcher, D. L., R. H. Harms, and D. M. Janky, 1978. Yolk color characteristics, xanthophyll availability and a model system for predicting egg yolk color using 0-apo-8'-carotenal and canthaxanthin. Poultry Sci. 57:624-629. Fry, J. L., E. M. Ahmed, G. M. Herrick, and R. H. Harms, 1969. A reflectance method of determining skin and shank pigmentation. Poultry Sci. 48:1127-1129. Fry, J. L., and B. L. Damron, 1971. Computer calculation of poultry and egg pigmentation data. FoodTechnol. 2 5 : 4 4 - 4 5 . Fry, J. L., and R. H. Harms, 1975. Yolk color, candled egg grade and xanthophyll availability from dietary natural pigmenting ingredients. Poultry Sci. 54:1094-1101. Fry, J. L., G. M. Herrick, and R. H. Harms, 1967. Yolk pigmenting value of dried kenaf tops. Q. J. Florida Acad. Sci. 3O(4):295-30O. Grau, C. R., and N. W. Klein, 1957. Sewage-grown algae as a feedstuff for chicks. Poultry Sci. 36: 1046-1051. Jensen, A., 1963. The effect of seaweed carotenoids on egg yolk coloration. Poultry Sci. 4 2 : 9 1 2 916. Littlefield, L. H., J. K. Bietner, and O. E. Goff, 1973. The effect of feeding laying hens various levels of cow manure on the pigmentation of egg yolks. Poultry Sci. 5 2 : 1 7 9 - 1 8 1 . Madiedo, C , and M. L. Sunde, 1962. The effect of algae, dried lakeweed, alfalfa meal, and ethoxyquin on yolk color. Poultry Sci. 41:1660. (Abstr.) Morehouse, A. L., 1961. Dried algae meal as a source of xanthophyll for egg yolk pigmentation. Poultry Sci. 40:1432. Morgan, W. A., and J. G. Woodroof, 1927. Waste pimento pepper for color in egg yolks. Georgia Exp. Sta. Bull. 147. Nelson, T. S., and J. N. Baptist, 1968. Feed pigments. 2. The influence of feeding single and combined sources of red and yellow pigment on egg yolk color. Poultry Sci. 4 7 : 9 2 4 - 9 3 1 . Runnels, T. D., E. F. Waller, E. G. Kelly, and S. Krulick, 1951. Growth promotion and pigmentation properties of dehydrated broccoli leaf meal in a practical broiler diet. Poultry Sci. 30: 930. (Abstr.) Statistical Analysis System, 1972. A user's guide to the statistical analysis system. SAS Inst., Raleigh, NC. Steel, R.G.D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., Inc., New York, NY.
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birds fed citrus sludge at all dietary xanthophyll levels tested (Table 6). In this trial, however, shank DWL for birds fed yellow corn appeared to decfease as dietary xanthophyll level was increased (Table 6). This was expected, since the addition of yellow pigment from yellow corn should overshadow the color of a completely pigment-free shank. There were no significant differences in shank LUM values as dietary xanthophyll level was increased or between dietary pigment sources (Table 6). From the data obtained in Trials 1 and 2 with broilers, it was concluded that the xanthophyll component of citrus sludge was not deposited at an efficient level in broiler skin, regardless of the level fed.
477