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Sewage-Grown Algae as a Feedstuff for Chicks*
1046
M. A. KHEIRELDIN AND C. S. SHAITNER SUMMARY
Pedigreed New Hampshire chicks from six different sires mated to five dams each were used to test for genetic differences in resistance to high levels of thyroprotein (Protamone). Protamone was fed at levels of 60 and 120 grams per 100 pounds of feed. Growth to four weeks of age was depressed by the treatments, there being more depression at the higher level. At the lower level, there was a significant treatment genotype interaction which was not present at the higher level. When chicks were fed Protamone at the 60-gram level the mortality was 2 percent while at the 120-gram level it was 27 percent. REFERENCES Boone, M. A., J. A. Davidson and E. P. Reineke, 1950. Thyroid studies in fast and slow feathering Rhode Island Red chicks. Poultry Sci. 29: 195203. Glazener, E. W., C. S. Shaffner and M. A. Jull, 1949. Thyroid activity as related to strain differences in growing chickens. Poultry Sci. 28: 834-849. Irwin, M. R., E. P. Reineke and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering and weights of glands of young chicks. Poultry Sci. 22:374-380.. Turner, C. W., M. R. Irwin and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23: 242-246.
Sewage-Grown Algae as a Feedstuff for Chicks* C. R. GRAU AND ,N. W. KLEIN Department of Poultry Husbandry, University of California, Davis (Received for publication April 29, 1957)
T
HE culture of unicellular algae such as Chlorella or Scenedesmus in sewage, in order to provide oxygen for aerobic bacterial decomposition of the organic
* The research was supported in part by grantsin-aid from the Rockefeller Foundation and the National Institutes of Health.
matter, results in a large mass of algae cells that may be removed and utilized as a source of protein and other nutrients for chicks. The dried material contains 40% or more protein, and significant amounts of carotenoids. Protein concentrates of this sort are always needed by the poultry industry in order to supple-
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 27, 2015
to 120 grams per 100 pounds of feed in the second trial, no significant interaction existed between either the treatment and sire families or the treatment and dam families within sires. It was observed that the mortality was almost negligible in the first trial but was considerable in the second trial (Table 6), ranging from 5.5 to 51.4 percent for the progeny of different sire families. A Chi square test showed that a highly significant difference existed in the mortality of the progeny from different sires, and that there was a significant difference in the mortality of the progeny of the different dams. No significant differences existed between the percentage mortality of the progeny from dams within sire families. The highly significant differences in the mortality between the progeny of different sires could be an explanation why no significant differences were observed in treatment sire interaction in the second trial. It might be possible that the toxic level of 120 grams of Protamone killed all the birds that were at or below a threshold level of resistance to that drug, thus eliminating all the birds that would otherwise have shown treatment response.
SEWAGE-GROWN ALGAE AS A FEEDSTUFF
Fink (1955) reported studies with rats in which the protein quality of Scenedesmus obliquus was compared with that of egg and milk. There was some indication that algae compared favorably with these other sources of protein, but because of the high mortality associated with the milk and egg diets and the resulting small number of experimental animals, these findings appear questionable. A study by Hundley and Ing (1956) who also used rats, suggested that Chlorella pyrenoidosa was a better source of the amino acid threonine than purified soybean protein. The availability of lysine in Scenedesmus obliquus was also considered, but the results were inconclusive. This work was limited in scope because the amount of dried algae was insufficient to allow replication. In the present study, we have attempted to evaluate algae grown in sewage as a feedstuff for young chicks. Our •0
primary interest has been in its protein value, since this would probably be its greatest asset under practical feeding conditions. Several other factors are involved in a preliminary evaluation of this, however: (a) tolerance for the flocculating agent used; (b) tolerance by the animal for the algae itself; (c) supplementary value of the protein for other feedstuffs; (d) quality of the protein as the principal or only amino acid source; (e) utilizability of the non-protein components such as energy, pigments, minerals, etc. From preliminary work, it is clear that algae can be used as a poultry feedstuff. Long-term and large-scale studies will eventually be needed to clarify the more practical parts of the problem. MATERIALS AND METHODS
All feeding trials were performed with White Leghorn chicks which were fed a stock diet (commercial chick starter) for ten days after hatching, and were then fed the experimental diets for the next eight days. The chicks were kept caged in groups of four and allowed feed and water ad libitum. Twelve chicks were used on each diet. The procedure of using the period of rapid early growth for evaluation of feed adequacy has been found to give reliable information on similar nutritional problems involving the chick (Grau and Williams, 1955). It is especially useful when only small quantities of material are available. Quantitative aluminum determinations were made on most samples. The methods of plant material analysis, as outlined by the A.O.A.C. (8th Ed.) were used. Three crude protein determinations were made on alum flocculated algae (39.0%, 31.1%, 41.4%) and one on a sample prepared ^jby centrifugation (43.7%). Since the research was of a preliminary nature, all diets were prepared
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 27, 2015
ment the cereal grains, which are relatively low in protein. Most studies of algae as poultry feedstuffs have been made with the large marine forms (Maclntyre, 1955) rather than with unicellular species. However, some nutritional work has been done with these simpler forms grown on a small scale and using artificial media. Combs (1952) found that feeding levels of 10% Chlorella pyrenoidosa increased feed efficiency and growth in chicks when the basal diet was deficient in riboflavin, vitamin Bj.2 and vitamin A activity, thus indicating that the algae contributed significant amounts of these nutrients. However, the inclusion of Chlorella pyrenoidosa in the diet resulted in poorer growth than that obtained with a complete broiler mash. This effect was attributed to the hygroscopic nature of the vacuum-dried algae which inhibited normal intake by causing impacted beaks.
1047
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C. R. GRAU AND N. W. KLEIN
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TABLE 1.—Commercial-type diet on the assumption that the algae samples contained approximately 40% crude proIngredient % tein. 37.5 Quantities of serum, obtained by allow- Corn, yellow, ground 25.9 Wheat, ground ing pooled samples of blood to clot, were Cottonseed meal, 4 1 % protein 4.7 precipitated with acetone and then the Fish meal, 65% protein 9.4 transmission of the supernatant was Soybean oil meal, 44% protein 14.1 measured at 445 m/j on a Beckman, Model Alfalfa meal, dehydrated 3.8 B, Spectrophotometer. This procedure pro- Whey, dried 1.2 Bonemeal, special steamed 0.9 vided the serum xanthophyll estimates. Salt _ 0.28 Chromatographic procedures (Bickoff Choline chloride 0.02 200 mg./kg. el ah, 1954) have been used in a preliminary Niacin Riboflavin 7 mg./kg. study in order to determine the concen- Vitamin D 700 I.C. units/kg. i60,000 U.S.P. units/kg. trations of various carotenoids in the al- Vitamin A gae material. The data obtained indicate that algae may compare favorably with tion with NaOH to pH 7.3 resulted in a alfalfa meal in the levels of xanthophyll growth rate that was definitely better present. than obtained with the untreated material. Neutralization alone, however, EXPERIMENTAL PROCEDURE AND produced results comparable to the acid RESULTS extracted-neutralized material. Since neuAlum. The effect of dietary aluminum tralization involves relatively inexpensive on chicks was considered an important materials and because this simple treatproblem since algae prepared by alum ment seemed to improve growth as well as flocculation more closely approximates the uneconomical extraction-neutralizamaterial which could be made commer- tion procedures, lime-treated algae was cially available through large-scale appli- considered in a few of the subsequent trials. In these first tests, the level of alcation. Various quantities of aluminum sulfate, gae was very high, and normal growth was neutralized with calcium hydroxide to pH not obtained. The results show, however, 7.0 were added to a stock basal diet. The that acid extraction alone is unsatisfacresults as measured by growth response tory. indicated that approximately 0.09% aluThe effects of alum will also be brought minum could be tolerated but levels above out in some of the following experiments 0.4% were quite detrimental. since algae materials prepared by different Attempts were made to alleviate the ef- methods were compared for other properfect caused by the aluminum and the acid- ties. ic (ca. pH 5.9) nature of the alum-floccuAlgae Tolerance. In order to compare lated algae. A single extraction with 0.6 N the chick tolerance for three types of alHC1 in order to remove some of the alu- gae meal, an experiment was performed minum resulted in material with a pH 2.2. in which the algae replaced corn in a comWhen this was fed at a level of 50% (in mercial type diet (Table 1). The algae order to provide the necessary 20% pro- were not required to furnish nutrients extein) growth was greatly depressed, pos- cept energy and the small amount of prosibly because of the acidity of the diet. tein that was present in the corn that was Acid extractions followed by neutraliza- replaced. The centrifuged sample was air
SEWAGE-GROWN ALGAE AS A FEEDSTUFF TABLE 2.—The tolerance of chicks for various algae preparations Level of algae meal in diet (replacing corn) 0 10 20 30
Growth rates (% gain per day) of chicks fed various dried algae preparations* None 7.1
Centrifuged
Alumized
Alumized and neutralized
6.9 6.9 6.7
6.6 5.9 5.3
7.0 6.2 4.9
* The growth rates (percent daily gain) were calculated for each group by dividing the average gain per day by the average of the initial and final weights, and multiplying by 100. All experiments lasted 8 days.
experiment, but the alumized algae constituted a different sample that was prepared by using a minimum amount of alum. This dried meal contained only 3.5% aluminum. The results (Table 3) indicate that this sample of alumized algae replaced the soybean oil meal satisfactorily. The other samples did not allow normal growth. Supplements of methionine and lysine were added to the neutralized, alumflocculated algae, but did not improve the rate of chick growth (Table 4). In this experiment also, the soybean oil meal of the practical diet (Table 1) was replaced by algae meal. The data reported in Table 5 are taken from an experiment in which various levels of soybean oil meal were combined with various levels of alum-flocculated algae meal in complete replacement of the dietary protein. Except for the protein source, the diet was composed of purified materials (Table 6). DL methionine (0.2%) was added to all the diets to assure an adequate supply of this essential amino acid. The results presented in Table 5 show clearly that when half or more of the total protein was derived from algae, the growth rate was suboptimal (last three diets). The results with lower levels of algae cannot be interpreted unequivocally, even though it appears that even 3 % algae protein {i.e., about 8% algae meal) T A B L E 3.—Algae meals as a replacement for 14.1% soybean oil meal in a practical diet
% aluminum in t h e diet
Growth rate ( % gain per day)
Soybean oil meal
N o t determined
7.1
Algae meals centrifuged alumized alumized and neutralized
0.014 0.49
6.4 7.3
0.62
5.8
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dried; the alumized sample was flocculated with alum and dried; the neutralized sample was similar to the alumized one except that the pH was adjusted to 8 with hydrated lime just after harvesting and before drying in air. The data of Table 2 indicate that centrifuged algae can be tolerated at levels as high as 20% of the diet. The effect of alum in reducing growth is evident in that with this sample even 10% algae did not allow maximum growth. The diet which contained 10% alumized (alum-flocculated) algae contained approximately 0.8% aluminum because the algae contained 8.0% aluminum. The neutralized and centrifuged algae contained 4.4% and 0.1% aluminum respectively. There were no significant beneficial effects from neutralization. Algae Protein. Combs (1952) reported that the concentrations of various amino acids in Chlorella protein compared favorably with soybean oil meal, except that the methionine level of the algae was lower. In the next experiment various algae preparations were compared in their ability to replace soybean oil meal in a a practical diet. The diet used was the same as that previously mentioned (Table 1) and the algae material substituted only for the 14.1% soybean oil meal. The neutralized and centrifuged materials were from the same lots used in the previous
1049
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C. R. GRAU AND N. W. KLEIN
TABLE 4.—.Amino acid supplementation of diets containing the alumized and neutralized algae studied previously (Table 3)
Addition to basal diet
Soybean oil meal
methionine
DL lysine HCl
%
%
DL
0.2
Algae meal 0.2 0.4 0.4
% 7.4 7.1 5.8 5.9 5.7 5.8 5.5 5.4
allowed poorer growth than did the soybean oil meal. In experiments of this type, a growth rate difference of approximately 0.5% per day is needed for significance. Thus, it is concluded that while a small amount of algae meal may be fed as a protein supplement to soybean oil meal in a purified diet, less can be used satisfactorily here than in the diets composed of natural materials used previously. Algae Carotenoids. In certain markets there is a preference for the yellow skin and shank condition that results from feeding xanthophyll and some other related carotenoids. Alfalfa meal and concentrates containing these pigments are TABLE 5.—Combinations of algae meal and soybean oil meal as the sole source of protein for chicks Protein supplied by soybean oil meal
Protein supplied by algae meal
%
%
%
20 17 14 10 6 3
— 3 6 10 14 17
8.0 7.5 7.2 6.2 6.0 5.5
Gain/day
Blood serum xanthophyll
micrograms/ml. 1.9 8.4 13.2
Ingredient
%
Soybean oil meal, 44% protein, or algae meal Crude soybean oil Glucose (cerelose) Mineral mixture* Vitamin mixture*
50 5 29 10 6
* The composition of the mineral and vitamin components has been published previously by Grau and Zweigart (1955).
often incorporated into broiler rati o n s t o impart this color. The study in which various quantities of algae and soyt>ean oil meal were combined to supply the entire protein (Table 5) clearly showed that the algae contain pigment available to the chick, since a positive relationship could be seen between the level of algae in the diet and the intensity of yellow pigmentation on the shank and skin of the chicks. These visual observations were confirmed by comparing the serum xanthophyll concentration at two levels of algae with the complete soybean oil meal protein diet. DISCUSSION The chick can tolerate diets containing up to 20% aluminum-free algae meal. The presence of significant amounts of aluminum in the meal resulting from alum-fiocculation harvesting procedures depresses chick growth. However, it appears that algae meals prepared with a minimum amount of alum compare favorably with meals harvested by centrifugation. This may indicate that chicks can tolerate at least 0.5% dietary aluminum or that there are considerable variations in the nutritional value of different samples of algae meal prepared under these conditions. Although algae protein was not benefited by supplements of lysine or methionine, these experiments did suggest that
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0.2 0.1 0.5
Growth rate (% gain per day)
TABLE 6.—Simplified diet
SEWAGE-GROWN ALGAE AS A FEEDSTUFF
SUMMARY
Sewage-grown algae meals, which contain about 40% crude protein, have been studied as sources of protein and other nutrients for young chicks. Both alumflocculated and centrifuged samples were fed. 1. Chicks tolerated as much as 20% of samples of algae meal in a diet. The presence of residual alum reduced this level to about 10%. 2. Neutralization and acid extraction have been unsuccessful in removing the harmful effects of the aluminum. 3. Algae flocculated with a minimum
amount of alum replaced 14.1% soybean oil meal successfully in a commercial-type diet, thus providing 6% crude protein, or more than one-fourth of the total dietary protein. 4. Algae contains significant amounts of xanthophyll pigments which are available to the chick for the production of yellow shanks and skin. ACKNOWLEDGEMENT
The samples of algae meal were provided through the courtesy of Professor H. B. Gotaas of the Engineering Field Station, University of California, Richmond, California. The crude protein values were obtained through the courtesy of V. P. Entwistle, Supervising Feed Chemist, California State Feed Laboratory. REFERENCES Bickoff, E. M., A. L. Livingston, G. F. Bailey and C. R. Thompson, 1954. Xanthophyll determination in dehydrated alfalfa meal. J. Assoc. Offic. Agric. Chem. 37: 894-902. Combs, G. F., 1952. Algae (Chlorella) as a source of nutrients for the chicks. Science, 116:453-454. Fink, H., 1955. On the protein quality and the liver necrosis preventive factor of unicellular algae. From a paper presented at the Conference on Solar Energy, University of Arizona, Tucson. Grau, C. R., and M. A. Williams, 1955. Fish meals as amino acid sources in chick rations. Poultry Sci. 34: 810-816. Grau, C. R., and P. A. Zweigart, 1955. The effect of various processing methods on the value of cottonseed meal as an amino acid source for chickens. Poultry Sci. 34: 724-728. Hundley, J. M., and R. B. Ing, 1956. Algae as sources of lysine and threonine in supplementing wheat and bread diets. Science, 124:536-537. Maclntyre, T. M., 1955. The digestibility of dried ground seaweed meal by the laying hen. Canadian J. Agric. Sci. 35:168-174. Official Methods of Analysis, 8th Ed., Association of Official Agricultural Chemists, Box 540, Benjamin Franklin Station, Washington 4, D. C, 1955, pp. 99-100.
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the protein was deficient or imbalanced. A comparison of the normal growth obtained when algae was fed to provide 6% protein in a practical diet containing several sources of protein (Table 3), with the poor growth when algae supplied 3 % protein to a diet containing only soybean oil meal as a source of additional protein (Table 5), indicates that one of these conditions exists in algae protein. The algae meals studied did not appear to be hygroscopic, and the condition of impacted beaks observed by Combs (1952) was not detected. The presence of dark, watery droppings was the only observed adverse effect of feeding algae meals. This condition was found with alum-flocculated and aluminum-free meals. The classification of various species of algae and other microbes found in the samples studied has not been considered as part of this research. However, Dr. C. G. Golueke, Assistant Research Biologist at the Richmond Station, mentioned in a private communication that variable ratios of Chlorella and Scenedesmus species probably comprise the bulk of this material.
1051
M. A. KHEIRELDIN AND C. S. SHAITNER SUMMARY
Pedigreed New Hampshire chicks from six different sires mated to five dams each were used to test for genetic differences in resistance to high levels of thyroprotein (Protamone). Protamone was fed at levels of 60 and 120 grams per 100 pounds of feed. Growth to four weeks of age was depressed by the treatments, there being more depression at the higher level. At the lower level, there was a significant treatment genotype interaction which was not present at the higher level. When chicks were fed Protamone at the 60-gram level the mortality was 2 percent while at the 120-gram level it was 27 percent. REFERENCES Boone, M. A., J. A. Davidson and E. P. Reineke, 1950. Thyroid studies in fast and slow feathering Rhode Island Red chicks. Poultry Sci. 29: 195203. Glazener, E. W., C. S. Shaffner and M. A. Jull, 1949. Thyroid activity as related to strain differences in growing chickens. Poultry Sci. 28: 834-849. Irwin, M. R., E. P. Reineke and C. W. Turner, 1943. Effect of feeding thyroactive iodocasein on growth, feathering and weights of glands of young chicks. Poultry Sci. 22:374-380.. Turner, C. W., M. R. Irwin and E. P. Reineke, 1944. Effect of feeding thyroactive iodocasein to Barred Rock cockerels. Poultry Sci. 23: 242-246.
Sewage-Grown Algae as a Feedstuff for Chicks* C. R. GRAU AND ,N. W. KLEIN Department of Poultry Husbandry, University of California, Davis (Received for publication April 29, 1957)
T
HE culture of unicellular algae such as Chlorella or Scenedesmus in sewage, in order to provide oxygen for aerobic bacterial decomposition of the organic
* The research was supported in part by grantsin-aid from the Rockefeller Foundation and the National Institutes of Health.
matter, results in a large mass of algae cells that may be removed and utilized as a source of protein and other nutrients for chicks. The dried material contains 40% or more protein, and significant amounts of carotenoids. Protein concentrates of this sort are always needed by the poultry industry in order to supple-
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 27, 2015
to 120 grams per 100 pounds of feed in the second trial, no significant interaction existed between either the treatment and sire families or the treatment and dam families within sires. It was observed that the mortality was almost negligible in the first trial but was considerable in the second trial (Table 6), ranging from 5.5 to 51.4 percent for the progeny of different sire families. A Chi square test showed that a highly significant difference existed in the mortality of the progeny from different sires, and that there was a significant difference in the mortality of the progeny of the different dams. No significant differences existed between the percentage mortality of the progeny from dams within sire families. The highly significant differences in the mortality between the progeny of different sires could be an explanation why no significant differences were observed in treatment sire interaction in the second trial. It might be possible that the toxic level of 120 grams of Protamone killed all the birds that were at or below a threshold level of resistance to that drug, thus eliminating all the birds that would otherwise have shown treatment response.
SEWAGE-GROWN ALGAE AS A FEEDSTUFF
Fink (1955) reported studies with rats in which the protein quality of Scenedesmus obliquus was compared with that of egg and milk. There was some indication that algae compared favorably with these other sources of protein, but because of the high mortality associated with the milk and egg diets and the resulting small number of experimental animals, these findings appear questionable. A study by Hundley and Ing (1956) who also used rats, suggested that Chlorella pyrenoidosa was a better source of the amino acid threonine than purified soybean protein. The availability of lysine in Scenedesmus obliquus was also considered, but the results were inconclusive. This work was limited in scope because the amount of dried algae was insufficient to allow replication. In the present study, we have attempted to evaluate algae grown in sewage as a feedstuff for young chicks. Our •0
primary interest has been in its protein value, since this would probably be its greatest asset under practical feeding conditions. Several other factors are involved in a preliminary evaluation of this, however: (a) tolerance for the flocculating agent used; (b) tolerance by the animal for the algae itself; (c) supplementary value of the protein for other feedstuffs; (d) quality of the protein as the principal or only amino acid source; (e) utilizability of the non-protein components such as energy, pigments, minerals, etc. From preliminary work, it is clear that algae can be used as a poultry feedstuff. Long-term and large-scale studies will eventually be needed to clarify the more practical parts of the problem. MATERIALS AND METHODS
All feeding trials were performed with White Leghorn chicks which were fed a stock diet (commercial chick starter) for ten days after hatching, and were then fed the experimental diets for the next eight days. The chicks were kept caged in groups of four and allowed feed and water ad libitum. Twelve chicks were used on each diet. The procedure of using the period of rapid early growth for evaluation of feed adequacy has been found to give reliable information on similar nutritional problems involving the chick (Grau and Williams, 1955). It is especially useful when only small quantities of material are available. Quantitative aluminum determinations were made on most samples. The methods of plant material analysis, as outlined by the A.O.A.C. (8th Ed.) were used. Three crude protein determinations were made on alum flocculated algae (39.0%, 31.1%, 41.4%) and one on a sample prepared ^jby centrifugation (43.7%). Since the research was of a preliminary nature, all diets were prepared
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 27, 2015
ment the cereal grains, which are relatively low in protein. Most studies of algae as poultry feedstuffs have been made with the large marine forms (Maclntyre, 1955) rather than with unicellular species. However, some nutritional work has been done with these simpler forms grown on a small scale and using artificial media. Combs (1952) found that feeding levels of 10% Chlorella pyrenoidosa increased feed efficiency and growth in chicks when the basal diet was deficient in riboflavin, vitamin Bj.2 and vitamin A activity, thus indicating that the algae contributed significant amounts of these nutrients. However, the inclusion of Chlorella pyrenoidosa in the diet resulted in poorer growth than that obtained with a complete broiler mash. This effect was attributed to the hygroscopic nature of the vacuum-dried algae which inhibited normal intake by causing impacted beaks.
1047
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C. R. GRAU AND N. W. KLEIN
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 27, 2015
TABLE 1.—Commercial-type diet on the assumption that the algae samples contained approximately 40% crude proIngredient % tein. 37.5 Quantities of serum, obtained by allow- Corn, yellow, ground 25.9 Wheat, ground ing pooled samples of blood to clot, were Cottonseed meal, 4 1 % protein 4.7 precipitated with acetone and then the Fish meal, 65% protein 9.4 transmission of the supernatant was Soybean oil meal, 44% protein 14.1 measured at 445 m/j on a Beckman, Model Alfalfa meal, dehydrated 3.8 B, Spectrophotometer. This procedure pro- Whey, dried 1.2 Bonemeal, special steamed 0.9 vided the serum xanthophyll estimates. Salt _ 0.28 Chromatographic procedures (Bickoff Choline chloride 0.02 200 mg./kg. el ah, 1954) have been used in a preliminary Niacin Riboflavin 7 mg./kg. study in order to determine the concen- Vitamin D 700 I.C. units/kg. i60,000 U.S.P. units/kg. trations of various carotenoids in the al- Vitamin A gae material. The data obtained indicate that algae may compare favorably with tion with NaOH to pH 7.3 resulted in a alfalfa meal in the levels of xanthophyll growth rate that was definitely better present. than obtained with the untreated material. Neutralization alone, however, EXPERIMENTAL PROCEDURE AND produced results comparable to the acid RESULTS extracted-neutralized material. Since neuAlum. The effect of dietary aluminum tralization involves relatively inexpensive on chicks was considered an important materials and because this simple treatproblem since algae prepared by alum ment seemed to improve growth as well as flocculation more closely approximates the uneconomical extraction-neutralizamaterial which could be made commer- tion procedures, lime-treated algae was cially available through large-scale appli- considered in a few of the subsequent trials. In these first tests, the level of alcation. Various quantities of aluminum sulfate, gae was very high, and normal growth was neutralized with calcium hydroxide to pH not obtained. The results show, however, 7.0 were added to a stock basal diet. The that acid extraction alone is unsatisfacresults as measured by growth response tory. indicated that approximately 0.09% aluThe effects of alum will also be brought minum could be tolerated but levels above out in some of the following experiments 0.4% were quite detrimental. since algae materials prepared by different Attempts were made to alleviate the ef- methods were compared for other properfect caused by the aluminum and the acid- ties. ic (ca. pH 5.9) nature of the alum-floccuAlgae Tolerance. In order to compare lated algae. A single extraction with 0.6 N the chick tolerance for three types of alHC1 in order to remove some of the alu- gae meal, an experiment was performed minum resulted in material with a pH 2.2. in which the algae replaced corn in a comWhen this was fed at a level of 50% (in mercial type diet (Table 1). The algae order to provide the necessary 20% pro- were not required to furnish nutrients extein) growth was greatly depressed, pos- cept energy and the small amount of prosibly because of the acidity of the diet. tein that was present in the corn that was Acid extractions followed by neutraliza- replaced. The centrifuged sample was air
SEWAGE-GROWN ALGAE AS A FEEDSTUFF TABLE 2.—The tolerance of chicks for various algae preparations Level of algae meal in diet (replacing corn) 0 10 20 30
Growth rates (% gain per day) of chicks fed various dried algae preparations* None 7.1
Centrifuged
Alumized
Alumized and neutralized
6.9 6.9 6.7
6.6 5.9 5.3
7.0 6.2 4.9
* The growth rates (percent daily gain) were calculated for each group by dividing the average gain per day by the average of the initial and final weights, and multiplying by 100. All experiments lasted 8 days.
experiment, but the alumized algae constituted a different sample that was prepared by using a minimum amount of alum. This dried meal contained only 3.5% aluminum. The results (Table 3) indicate that this sample of alumized algae replaced the soybean oil meal satisfactorily. The other samples did not allow normal growth. Supplements of methionine and lysine were added to the neutralized, alumflocculated algae, but did not improve the rate of chick growth (Table 4). In this experiment also, the soybean oil meal of the practical diet (Table 1) was replaced by algae meal. The data reported in Table 5 are taken from an experiment in which various levels of soybean oil meal were combined with various levels of alum-flocculated algae meal in complete replacement of the dietary protein. Except for the protein source, the diet was composed of purified materials (Table 6). DL methionine (0.2%) was added to all the diets to assure an adequate supply of this essential amino acid. The results presented in Table 5 show clearly that when half or more of the total protein was derived from algae, the growth rate was suboptimal (last three diets). The results with lower levels of algae cannot be interpreted unequivocally, even though it appears that even 3 % algae protein {i.e., about 8% algae meal) T A B L E 3.—Algae meals as a replacement for 14.1% soybean oil meal in a practical diet
% aluminum in t h e diet
Growth rate ( % gain per day)
Soybean oil meal
N o t determined
7.1
Algae meals centrifuged alumized alumized and neutralized
0.014 0.49
6.4 7.3
0.62
5.8
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dried; the alumized sample was flocculated with alum and dried; the neutralized sample was similar to the alumized one except that the pH was adjusted to 8 with hydrated lime just after harvesting and before drying in air. The data of Table 2 indicate that centrifuged algae can be tolerated at levels as high as 20% of the diet. The effect of alum in reducing growth is evident in that with this sample even 10% algae did not allow maximum growth. The diet which contained 10% alumized (alum-flocculated) algae contained approximately 0.8% aluminum because the algae contained 8.0% aluminum. The neutralized and centrifuged algae contained 4.4% and 0.1% aluminum respectively. There were no significant beneficial effects from neutralization. Algae Protein. Combs (1952) reported that the concentrations of various amino acids in Chlorella protein compared favorably with soybean oil meal, except that the methionine level of the algae was lower. In the next experiment various algae preparations were compared in their ability to replace soybean oil meal in a a practical diet. The diet used was the same as that previously mentioned (Table 1) and the algae material substituted only for the 14.1% soybean oil meal. The neutralized and centrifuged materials were from the same lots used in the previous
1049
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C. R. GRAU AND N. W. KLEIN
TABLE 4.—.Amino acid supplementation of diets containing the alumized and neutralized algae studied previously (Table 3)
Addition to basal diet
Soybean oil meal
methionine
DL lysine HCl
%
%
DL
0.2
Algae meal 0.2 0.4 0.4
% 7.4 7.1 5.8 5.9 5.7 5.8 5.5 5.4
allowed poorer growth than did the soybean oil meal. In experiments of this type, a growth rate difference of approximately 0.5% per day is needed for significance. Thus, it is concluded that while a small amount of algae meal may be fed as a protein supplement to soybean oil meal in a purified diet, less can be used satisfactorily here than in the diets composed of natural materials used previously. Algae Carotenoids. In certain markets there is a preference for the yellow skin and shank condition that results from feeding xanthophyll and some other related carotenoids. Alfalfa meal and concentrates containing these pigments are TABLE 5.—Combinations of algae meal and soybean oil meal as the sole source of protein for chicks Protein supplied by soybean oil meal
Protein supplied by algae meal
%
%
%
20 17 14 10 6 3
— 3 6 10 14 17
8.0 7.5 7.2 6.2 6.0 5.5
Gain/day
Blood serum xanthophyll
micrograms/ml. 1.9 8.4 13.2
Ingredient
%
Soybean oil meal, 44% protein, or algae meal Crude soybean oil Glucose (cerelose) Mineral mixture* Vitamin mixture*
50 5 29 10 6
* The composition of the mineral and vitamin components has been published previously by Grau and Zweigart (1955).
often incorporated into broiler rati o n s t o impart this color. The study in which various quantities of algae and soyt>ean oil meal were combined to supply the entire protein (Table 5) clearly showed that the algae contain pigment available to the chick, since a positive relationship could be seen between the level of algae in the diet and the intensity of yellow pigmentation on the shank and skin of the chicks. These visual observations were confirmed by comparing the serum xanthophyll concentration at two levels of algae with the complete soybean oil meal protein diet. DISCUSSION The chick can tolerate diets containing up to 20% aluminum-free algae meal. The presence of significant amounts of aluminum in the meal resulting from alum-fiocculation harvesting procedures depresses chick growth. However, it appears that algae meals prepared with a minimum amount of alum compare favorably with meals harvested by centrifugation. This may indicate that chicks can tolerate at least 0.5% dietary aluminum or that there are considerable variations in the nutritional value of different samples of algae meal prepared under these conditions. Although algae protein was not benefited by supplements of lysine or methionine, these experiments did suggest that
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0.2 0.1 0.5
Growth rate (% gain per day)
TABLE 6.—Simplified diet
SEWAGE-GROWN ALGAE AS A FEEDSTUFF
SUMMARY
Sewage-grown algae meals, which contain about 40% crude protein, have been studied as sources of protein and other nutrients for young chicks. Both alumflocculated and centrifuged samples were fed. 1. Chicks tolerated as much as 20% of samples of algae meal in a diet. The presence of residual alum reduced this level to about 10%. 2. Neutralization and acid extraction have been unsuccessful in removing the harmful effects of the aluminum. 3. Algae flocculated with a minimum
amount of alum replaced 14.1% soybean oil meal successfully in a commercial-type diet, thus providing 6% crude protein, or more than one-fourth of the total dietary protein. 4. Algae contains significant amounts of xanthophyll pigments which are available to the chick for the production of yellow shanks and skin. ACKNOWLEDGEMENT
The samples of algae meal were provided through the courtesy of Professor H. B. Gotaas of the Engineering Field Station, University of California, Richmond, California. The crude protein values were obtained through the courtesy of V. P. Entwistle, Supervising Feed Chemist, California State Feed Laboratory. REFERENCES Bickoff, E. M., A. L. Livingston, G. F. Bailey and C. R. Thompson, 1954. Xanthophyll determination in dehydrated alfalfa meal. J. Assoc. Offic. Agric. Chem. 37: 894-902. Combs, G. F., 1952. Algae (Chlorella) as a source of nutrients for the chicks. Science, 116:453-454. Fink, H., 1955. On the protein quality and the liver necrosis preventive factor of unicellular algae. From a paper presented at the Conference on Solar Energy, University of Arizona, Tucson. Grau, C. R., and M. A. Williams, 1955. Fish meals as amino acid sources in chick rations. Poultry Sci. 34: 810-816. Grau, C. R., and P. A. Zweigart, 1955. The effect of various processing methods on the value of cottonseed meal as an amino acid source for chickens. Poultry Sci. 34: 724-728. Hundley, J. M., and R. B. Ing, 1956. Algae as sources of lysine and threonine in supplementing wheat and bread diets. Science, 124:536-537. Maclntyre, T. M., 1955. The digestibility of dried ground seaweed meal by the laying hen. Canadian J. Agric. Sci. 35:168-174. Official Methods of Analysis, 8th Ed., Association of Official Agricultural Chemists, Box 540, Benjamin Franklin Station, Washington 4, D. C, 1955, pp. 99-100.
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the protein was deficient or imbalanced. A comparison of the normal growth obtained when algae was fed to provide 6% protein in a practical diet containing several sources of protein (Table 3), with the poor growth when algae supplied 3 % protein to a diet containing only soybean oil meal as a source of additional protein (Table 5), indicates that one of these conditions exists in algae protein. The algae meals studied did not appear to be hygroscopic, and the condition of impacted beaks observed by Combs (1952) was not detected. The presence of dark, watery droppings was the only observed adverse effect of feeding algae meals. This condition was found with alum-flocculated and aluminum-free meals. The classification of various species of algae and other microbes found in the samples studied has not been considered as part of this research. However, Dr. C. G. Golueke, Assistant Research Biologist at the Richmond Station, mentioned in a private communication that variable ratios of Chlorella and Scenedesmus species probably comprise the bulk of this material.
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