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A Study of the Protein Quality of Different Feather Meals
A Study of the Protein Quality of Different Feather Meals J. P. H. WESSELS 1 Faculty of Agriculture, University of Natal, Pietermaritzburg, Republic of South Africa (Received for publication July 23, 1971)
POULTRY SCIENCE 5 1 : 537-541,
EATHER meal (hydrolysed feathers) is more useful than raw feathers as a feed ingredient for chickens, but the protein quality of this product has been shown to be poor (e.g. McCasland and Richardson, 1966; and Moran et al., 1966). No attempt has so far been made to establish the order in which amino acids become limiting for chickens or rats, yet several workers have illustrated that supplementation with methionine (Moran et al., 1969) or methionine and tryptophan (McCasland et al., 1966; Moran et al., 1966) or lysine (Gehle et al., 1967) or lysine, methionine, tryptophan and histidine (Naber et al., 1961) improved animal performance. Feather meal became available commercially in South Africa during the last year. This publication represents the results of the first effort to learn something about the available amino acid make-up of the local product (Trial 1). The second phase of the work consists of a comparison between the South African product and meals of Cana-
F
1 Present address: Fishing Industry Research Institute, Private Bag, Rondebosch, Cape Province, South Africa.
1972
dian and Argentinian origin obtained from a London dealer (Trial 2). MATERIALS AND METHODS
Net Protein Utilization (N.P.U.) determinations were done in two trials. In the first trial a South African feather meal (amino acid composition as determined at this University by automatic gas-liquid chromatography in Table 1) was supplemented with the following amino acids singly and in all possible combinations: lysine, methionine, histidine, tryptophan and tyrosine. In the second experiment each of three feather meals was supplemented with lysine, methionine and histidine, singly and in all possible combinations. The South African meal was very light brown in color, the Argentinian meal dark brown (with a burnt smell), and the Canadian meal of intermediate color. The N contents of the meals were 12.9%, 13.1% and 13.3% respectively for the Argentinian, Canadian and South African feather meals, and the ether extract contents 27.5%, 9.8% and 11.9%. Diets: The composition of the basal diet
537
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
ABSTRACT Nitrogen retention by chickens served as criterion of the response of three hydrolysed feather meals in two factorial experiments. The South African feather meal used in the first trial gave better N retention when supplemented with methionine, lysine, histidine and tyrosine, while tryptophan supplementation had no effect. The amino acids evidently become limiting in the order in which they are listed. Yet added methionine would only give a response when supplemental lysine (but not supplemental histidine) was present. An Argentinian hydrolysed feather meal of dark colour proved to be more poorly utilized than the South African and Canadian meals studied, whether or not supplemented with lysine and/or methionine and/or histidine. There was a significant meal X histidine supplementation interaction with the South African meal only responding to histidine supplementation. With methionine plus lysine added the Canadian meal gave slightly higher N retention than the South African feather meal, but when histidine was also added, the meals gave similar performances.
538
J. P. H. WESSELS TABLE 1.—The amino acid composition of a South African feather meal Content mg./16g.N
Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Half cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine
2.28 Trace 4.33 3.41 2.50 5.67 6.85 6.76 4.21 2.64 6.43 4.01 0.35 2.96 5.40 1.85 3.15
appears in Table 2. This diet comprised 82.6% of the experimental diets. Feather meal and amino acids were added to provide about 1.8% nitrogen (N) in the experimental diets, and sucrose was used to bring all diets to the same total weight, while in the 'N-free' diet starch was used to bring it up to weight. Where amino acids were added, no correction was made to keep the diets isonitrogenous. The N content of the diets therefore varied from 1.638 to 2.015% in the first trial and 1.705 to 2.036% in the second. Amino acids were added in the forms and at levels indicated below: L-lysine hydrochloride at 0.6% of the diet; DL-methionine at 0.5% of the diet; L-histidine (free base) at 0.3% of the diet; L-tyrosine at 0.4% of the diet; and L-tryptophan at 0.1% of the diet. Experimental animals, housing statistical design and analysis: White Leghorn X Australorp male chickens were used in both trials, five chickens per experimental group. Five-tier electrically heated brooders with four compartments per tier housed the ex-
General experimental procedure: The chickens were given a conventional chicken mash until they were six days old, then starved overnight, weighed and allocated to their respective groups in such a way that the total group weights were practically identical. They were then given free access to the experimental diets for the next eight days, starved overnight, weighed and killed with chloroform. Group food consumption TABLE 2.—The composition of the basal ration Ingredient Starch Sucrose Vegetable oil Mineral mix* Vitamin mix** Choline chloride
Percentage 72.7 20.0 3.0 4.0 0.15 0.15 100.0
* CaHP0 4 , 2,000 g.; KH 2 P0 4 , 1,050 g.; NaCI, 800 g.; CaCOs, 1,900 g.; Fe-citrate, 50 g.; MgSO,, 250 g.; MnS0 4 -H 2 0, 20 g.; KI, 1 g.; CuS0 4 -5H 2 0, 1.78 g.; ZnC0 3 , 20 g.; Na 2 Mo0 4 -H 2 0, I g. ** Thiamine-HC1, 25 g.; Riboflavin, 16 g.; Capantothenate, 20 g.; Pyridoxine, 6 g.; Biotin, 0.6 g.; Folic acid, 4 g.; Menadione, 5 g.; Vitamin Bu, 0.02 g.; Nicotinic acid, 150 g.; Ascorbic acid, 250 g.; Vitamin A, 990,000 I.U.; Vitamin D 3 , 576,000 I.U.; Alpha-tocopherol, 8.4 g.
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
Amino acid
periments. In the first trial two sets of two brooders each comprised a block and the 32 treatments were randomly allocated to compartments within each block. Each treatment was replicated. In the second trial the 24 treatments were randomly allocated to the 72 compartments with three replicates per treatment. In addition one compartment in each border was set aside for a 'N-free' treatment, the performance of which was needed for the calculation of N.P.U. values. However, statistical analysis was not based on N.P.U. values. Covariance analysis was performed with group N intake as covariant to remove its effect on group body moisture content. The first trial was a 25 and the second a 3 X 23 factorial experiment.
539
FEATHER MEALS PROTEIN QUALITY
y = 121.6 + 33. lx (where y represents body N in mg., and x represents body water content in g.). This equation is based on results of work done by Wessels and Bundock (1968) using chickens of the type employed in these trials. N.P.U. values (Bender andDoell, 1957) were calculated using the formula: B f - B k + I k X 100 N.P.U. = If
where B t and If represent the body N and feed N intake of a group of chickens which received a particular experimental diet and Bk and I k the average body N and feed N intake of the groups which received the 'N-free' diet. TABLE 3.—N retention (body moisture as criterion) of chickens given South African feather meal with or without amino acid supplementation
Amino acid
Lysine Methionine Histidine Tryptophan Tyrosine
Average: N retained/group (given as> g. body moisture) Without
With
Difference
185.58 183.82 185.21 192.38 189.67
197.87 199.60 198.21 191.04 193.75
12.29** 15.78** 13.00** -1.34 4.08*
* Indicates significance at p<0.05. ** Indicates significance at p<0.01.
TABLE 4.—N retention of chickens given South African feather meal with or without amino acid supplementation Amino acid supplementation
Average N retained/group (given as g. body moisture) Without methionine
With methionine
Without lysine With lysine
185.26 182.38
185.83 213.37
Difference
-2.88
Without histidine With histidine
182.45 185.18
Difference
2.73 Without histidine
Without lysine With lysine Difference
185.58 184.85 -0.73
Difference 0.57 30.99**
27.54** 187.97 211.23
5.52* 26.05**
23.26** With Difference histidine 185.52 210.90
-0.06 26.05
25.38*
* Indicates significance at p<0.05. ** Indicates significance at p<0.01. RESULTS AND DISCUSSION
The data shown in Table 3 give the overall effects of supplementation of a South African feather meal with an amino acid, i.e. the average effect over all treatments or combinations of amino acid supplementation. Supplementation of the experimental diets with lysine, methionine and histidine on the average highly significantly improved N retention of chickens while tyrosine supplementation had a significant effect, and supplementation with tryptophan had no effect. The nature of these 'main effects' becomes clearer when one studies the interaction tables, Tables 4 and 5. Neither lysine on its own nor histidine on its own caused a significant improvement in N retention, but the 5.52 g. gain due to methionine supplementation in the absence of histidine supplementation was significant (Table 4). The 7.66 g. gain due to methionine supplementation in the absence of histidine but presence of supple-
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
was established. The individual carcass moisture content was obtained by determining the weight loss during a five-day minimum period in a forced draught oven run at 85°C. for the first two days and 105°C. thereafter (i.e. until a constant dried weight was reached). The N retention of the chickens was used as criterion of the value of the protein sources with or without amino acid supplementation. The body moisture content of carcasses served as an indication of the body N content. The relationship between body moisture content and body N is expressed by the equation:
540
J. P. H. WESSELS
TABLE 5.—The effect on N retention of chickens given South African feather meal of supplementation with lysine, methionine and histidine Average N retention/group (given as g. body moisture) :atment MethioNo methionine nine N o lysine
187.40 186.55 -0.85
-1.69
N o histidine Histidine
. 182.41 187.62
190.07 225.00
Difference Lysine Difference
5.21*
188.11 186.42
0.71 -0.13
7.66" 37.38**
34.93**
* Indicates significance at p<0.05. ** Indicates significance at p<0.01.
mental lysine, compared with the 0.71 g. non-significant response in the absence of supplemental lysine (Table 5) proves that the value of methionine supplementation was dependent upon the presence of added lysine. However, since supplemental lysine plus histidine in the absence of methionine did not give improved N retention it can be concluded that methionine was the first limiting amino acid in the particular feather meal. The absence of response to methionine and/or histidine supplementation as shown in the top half of Table S shows that lysine became limiting before histidine did. Histidine was then the third limiting amino acid in this feather meal and tyrosine evidently the fourth. The significant effect of tyrosine supplementation as shown in Table 3 can be attributed to a significant interaction of the third order (tyrosine gave improved N retention in the presence of lysine, methionine plus h;stidine) which cannot be presented easily in the form of a table. Comparison of three feather meals: Chickens given diets containing any of the three feather meals studied on the average (over all treatments) retained significantly (or in the case of the Canadian feather meal, highly significantly) more N when their diets were supplemented with lysine and
TABLE 6.—N retention of chickens given different feather meals with and without amino acid supplementation in Trial Z Treatment Feather meal
Average N retention/group (given as g. body moisture) Argentinian
Canadian South African
Without lysine With lysine Difference
136.21 138.99 2.78*
148.85 152.87 4.02**
147.64 150.01 2.37*
Without methionine With methionine Difference
136.02 139.18 3.16*
148.55 153.16 4.61**
147.35 150.30 2.95*
Without histidine With histidine Difference
137.80 137.39 -0.41
150.10 151.61 1.51
147.51 150.13 2.62*
* Indicates significance at p <0.05. ** Indicates significance at p <0.01.
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
N o histidine Histidine
Difference
methionine (Table 6). The Argentinian meal, both unsupplemented and supplemented with one, two or all three amino acids, gave highly significantly poorer N retention than the other two meals, while the Canadian meal, supplemented with lysine and methionine only, gave better N retention than the South African meal (p < 0.05). Supplementation with histidine which gave a significant improvement in N retention of chickens given the South African feather meal removed this difference between the two meals. In fact, the interaction between meals and histidine supplementation was statistically significant. The reason for the difference between the South African and Canadian feather meals may be attributable to a small contamination of the latter with blood, which increased its histidine content. The inferiority of the Argentinian meal might be due to a generally lower availability of amino acids in this product, which appeared to have been overheated in processing. The shortage of available methionine in feather meal has been illustrated by Moran et al. (1969) and earlier by workers such as McCasland et al. (1966) and Moran et al. (1966). Both these groups of researchers, using growth of rats or chickens as criterion, found tryptophan supplementation to be beneficial. The South African feather
FEATHER MEALS PROTEIN QUALITY
REFERENCES Bender, A. E., and B. H. Doell, 19S7. Biological evaluation of proteins: a new aspect. Brit. J. Nutr. 11: 140-148. Gehle, M. H., G. M. Speers, D. L. Miller and S. L. Balloun, 1967. Nutritive value of hog hair as a protein source for chicks and poults. Poultry Sci. 46: 156-164. McCasland, W. E., and L. R. Richardson, 1966. Methods for determinining the nutritive value of feather meals. Poultry Sci. 45: 1231-1236. Moran, E. T., W. F. Pepper, and J. D. Summers, 1969. Processed feather and hog hair meals as sources of dietary protein for the laying hen with emphasis on their use in meeting maintenance requirements. Poultry Sci. 48: 12451251. Moran, E. T., J. D. Summers and S. J. Slinger, 1966. Keratin as a source of protein for the growing chick. 1. Amino acid imbalance as the cause for inferior performance of feather meal and the implication of disulphide bonding in raw feathers as the reason for poor digestibility. Poultry Sci. 45: 1257-1266. Naber, E. C , S. P. Touchbum, B. D. Barnett and C. L. Morgan, 1961. Effect of processing method and amino acid supplementation of feather protein on dietary utilization by the chick. Poultry Sci. 40: 1234-1245. Wessels, J. P. H., and M. J. Bundock, 1968. Applicability to chickens of the carcass analysis method for determination of net protein utilization. III. The effect of shorter test period, sex and breed upon the body water-nitrogen relationship in the chicken. S. African J. Agric. Sci. 11: 531-536.
NEWS AND NOTES (Continued from page 536) sity, having edited the O.S.U. veterinary student publication, The Speculum. In 1957, after engaging in general practice in Bellingham, Washington, he became Diiector of Professional Relations for Jensen-Salsbery Laboratories in Kansas City, Missouri. Among his responsibilities was the editing of the Jen-Sal Journal. Since joining the A.V.M.A. staff in 1959, he has been responsible for editing the Journal of the American Veterinary Medical Association, convention proceedings, and proceedings of several special animal disease symposia co-sponsored by A.V.M.A. He is a member of the American Veterinary
Medical Association, the Illinois State Veterinary Medical Association, the Chicago Veterinary Medical Association, the American Society of Veterinary Physiologists and Pharmacologists, U. S. Animal Health Association, the Flying Veterinarians Association, Phi Zeta, and Alpha Psi. HUBBARD NOTES Dr. Thomas F. Savage has been appointed as Geneticist for Hubbard Farms, and assigned to the meat breeder section. He will be working with both basic and applied aspects of the programs involving the White Mountain male and the Hubbard Breeder
(Continued on page 546)
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meal was evidently so well processed that less destruction of tryptophan took place than was the case with meals used by these workers. While Moran et al. (1966) claimed that growth depression was completely overcome by supplementation with lysine, methionine and tryptophan, McCasland et al. (1966) only got reasonable growth on supplementation with these three amino acids plus histidine, while Naber et al. (1961) claimed that supplementation with amino acids other than these four was probably necessary for optimum chicken growth when diets contained high levels of feather meal. Their results might have been improved by the addition of tyrosine. Workers have not attempted to arrange amino acids in the order in which they become limiting for chicken growth. Yet Gehle et al. (1967) found lysine and not methionine to be the first limiting amino acid for chicken growth in hydrolysed hot hair (like feather meal a product of keratin hydrolysis). Unsupplemented, the South African meal gave a N.P.TJ. value of 38 in Trial 1 and of 54 when supplemented with the four amino acids methionine, lysine, histidine and tyrosine.
541
POULTRY SCIENCE 5 1 : 537-541,
EATHER meal (hydrolysed feathers) is more useful than raw feathers as a feed ingredient for chickens, but the protein quality of this product has been shown to be poor (e.g. McCasland and Richardson, 1966; and Moran et al., 1966). No attempt has so far been made to establish the order in which amino acids become limiting for chickens or rats, yet several workers have illustrated that supplementation with methionine (Moran et al., 1969) or methionine and tryptophan (McCasland et al., 1966; Moran et al., 1966) or lysine (Gehle et al., 1967) or lysine, methionine, tryptophan and histidine (Naber et al., 1961) improved animal performance. Feather meal became available commercially in South Africa during the last year. This publication represents the results of the first effort to learn something about the available amino acid make-up of the local product (Trial 1). The second phase of the work consists of a comparison between the South African product and meals of Cana-
F
1 Present address: Fishing Industry Research Institute, Private Bag, Rondebosch, Cape Province, South Africa.
1972
dian and Argentinian origin obtained from a London dealer (Trial 2). MATERIALS AND METHODS
Net Protein Utilization (N.P.U.) determinations were done in two trials. In the first trial a South African feather meal (amino acid composition as determined at this University by automatic gas-liquid chromatography in Table 1) was supplemented with the following amino acids singly and in all possible combinations: lysine, methionine, histidine, tryptophan and tyrosine. In the second experiment each of three feather meals was supplemented with lysine, methionine and histidine, singly and in all possible combinations. The South African meal was very light brown in color, the Argentinian meal dark brown (with a burnt smell), and the Canadian meal of intermediate color. The N contents of the meals were 12.9%, 13.1% and 13.3% respectively for the Argentinian, Canadian and South African feather meals, and the ether extract contents 27.5%, 9.8% and 11.9%. Diets: The composition of the basal diet
537
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
ABSTRACT Nitrogen retention by chickens served as criterion of the response of three hydrolysed feather meals in two factorial experiments. The South African feather meal used in the first trial gave better N retention when supplemented with methionine, lysine, histidine and tyrosine, while tryptophan supplementation had no effect. The amino acids evidently become limiting in the order in which they are listed. Yet added methionine would only give a response when supplemental lysine (but not supplemental histidine) was present. An Argentinian hydrolysed feather meal of dark colour proved to be more poorly utilized than the South African and Canadian meals studied, whether or not supplemented with lysine and/or methionine and/or histidine. There was a significant meal X histidine supplementation interaction with the South African meal only responding to histidine supplementation. With methionine plus lysine added the Canadian meal gave slightly higher N retention than the South African feather meal, but when histidine was also added, the meals gave similar performances.
538
J. P. H. WESSELS TABLE 1.—The amino acid composition of a South African feather meal Content mg./16g.N
Lysine Histidine Arginine Aspartic acid Threonine Serine Glutamic acid Proline Glycine Alanine Half cystine Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine
2.28 Trace 4.33 3.41 2.50 5.67 6.85 6.76 4.21 2.64 6.43 4.01 0.35 2.96 5.40 1.85 3.15
appears in Table 2. This diet comprised 82.6% of the experimental diets. Feather meal and amino acids were added to provide about 1.8% nitrogen (N) in the experimental diets, and sucrose was used to bring all diets to the same total weight, while in the 'N-free' diet starch was used to bring it up to weight. Where amino acids were added, no correction was made to keep the diets isonitrogenous. The N content of the diets therefore varied from 1.638 to 2.015% in the first trial and 1.705 to 2.036% in the second. Amino acids were added in the forms and at levels indicated below: L-lysine hydrochloride at 0.6% of the diet; DL-methionine at 0.5% of the diet; L-histidine (free base) at 0.3% of the diet; L-tyrosine at 0.4% of the diet; and L-tryptophan at 0.1% of the diet. Experimental animals, housing statistical design and analysis: White Leghorn X Australorp male chickens were used in both trials, five chickens per experimental group. Five-tier electrically heated brooders with four compartments per tier housed the ex-
General experimental procedure: The chickens were given a conventional chicken mash until they were six days old, then starved overnight, weighed and allocated to their respective groups in such a way that the total group weights were practically identical. They were then given free access to the experimental diets for the next eight days, starved overnight, weighed and killed with chloroform. Group food consumption TABLE 2.—The composition of the basal ration Ingredient Starch Sucrose Vegetable oil Mineral mix* Vitamin mix** Choline chloride
Percentage 72.7 20.0 3.0 4.0 0.15 0.15 100.0
* CaHP0 4 , 2,000 g.; KH 2 P0 4 , 1,050 g.; NaCI, 800 g.; CaCOs, 1,900 g.; Fe-citrate, 50 g.; MgSO,, 250 g.; MnS0 4 -H 2 0, 20 g.; KI, 1 g.; CuS0 4 -5H 2 0, 1.78 g.; ZnC0 3 , 20 g.; Na 2 Mo0 4 -H 2 0, I g. ** Thiamine-HC1, 25 g.; Riboflavin, 16 g.; Capantothenate, 20 g.; Pyridoxine, 6 g.; Biotin, 0.6 g.; Folic acid, 4 g.; Menadione, 5 g.; Vitamin Bu, 0.02 g.; Nicotinic acid, 150 g.; Ascorbic acid, 250 g.; Vitamin A, 990,000 I.U.; Vitamin D 3 , 576,000 I.U.; Alpha-tocopherol, 8.4 g.
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
Amino acid
periments. In the first trial two sets of two brooders each comprised a block and the 32 treatments were randomly allocated to compartments within each block. Each treatment was replicated. In the second trial the 24 treatments were randomly allocated to the 72 compartments with three replicates per treatment. In addition one compartment in each border was set aside for a 'N-free' treatment, the performance of which was needed for the calculation of N.P.U. values. However, statistical analysis was not based on N.P.U. values. Covariance analysis was performed with group N intake as covariant to remove its effect on group body moisture content. The first trial was a 25 and the second a 3 X 23 factorial experiment.
539
FEATHER MEALS PROTEIN QUALITY
y = 121.6 + 33. lx (where y represents body N in mg., and x represents body water content in g.). This equation is based on results of work done by Wessels and Bundock (1968) using chickens of the type employed in these trials. N.P.U. values (Bender andDoell, 1957) were calculated using the formula: B f - B k + I k X 100 N.P.U. = If
where B t and If represent the body N and feed N intake of a group of chickens which received a particular experimental diet and Bk and I k the average body N and feed N intake of the groups which received the 'N-free' diet. TABLE 3.—N retention (body moisture as criterion) of chickens given South African feather meal with or without amino acid supplementation
Amino acid
Lysine Methionine Histidine Tryptophan Tyrosine
Average: N retained/group (given as> g. body moisture) Without
With
Difference
185.58 183.82 185.21 192.38 189.67
197.87 199.60 198.21 191.04 193.75
12.29** 15.78** 13.00** -1.34 4.08*
* Indicates significance at p<0.05. ** Indicates significance at p<0.01.
TABLE 4.—N retention of chickens given South African feather meal with or without amino acid supplementation Amino acid supplementation
Average N retained/group (given as g. body moisture) Without methionine
With methionine
Without lysine With lysine
185.26 182.38
185.83 213.37
Difference
-2.88
Without histidine With histidine
182.45 185.18
Difference
2.73 Without histidine
Without lysine With lysine Difference
185.58 184.85 -0.73
Difference 0.57 30.99**
27.54** 187.97 211.23
5.52* 26.05**
23.26** With Difference histidine 185.52 210.90
-0.06 26.05
25.38*
* Indicates significance at p<0.05. ** Indicates significance at p<0.01. RESULTS AND DISCUSSION
The data shown in Table 3 give the overall effects of supplementation of a South African feather meal with an amino acid, i.e. the average effect over all treatments or combinations of amino acid supplementation. Supplementation of the experimental diets with lysine, methionine and histidine on the average highly significantly improved N retention of chickens while tyrosine supplementation had a significant effect, and supplementation with tryptophan had no effect. The nature of these 'main effects' becomes clearer when one studies the interaction tables, Tables 4 and 5. Neither lysine on its own nor histidine on its own caused a significant improvement in N retention, but the 5.52 g. gain due to methionine supplementation in the absence of histidine supplementation was significant (Table 4). The 7.66 g. gain due to methionine supplementation in the absence of histidine but presence of supple-
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
was established. The individual carcass moisture content was obtained by determining the weight loss during a five-day minimum period in a forced draught oven run at 85°C. for the first two days and 105°C. thereafter (i.e. until a constant dried weight was reached). The N retention of the chickens was used as criterion of the value of the protein sources with or without amino acid supplementation. The body moisture content of carcasses served as an indication of the body N content. The relationship between body moisture content and body N is expressed by the equation:
540
J. P. H. WESSELS
TABLE 5.—The effect on N retention of chickens given South African feather meal of supplementation with lysine, methionine and histidine Average N retention/group (given as g. body moisture) :atment MethioNo methionine nine N o lysine
187.40 186.55 -0.85
-1.69
N o histidine Histidine
. 182.41 187.62
190.07 225.00
Difference Lysine Difference
5.21*
188.11 186.42
0.71 -0.13
7.66" 37.38**
34.93**
* Indicates significance at p<0.05. ** Indicates significance at p<0.01.
mental lysine, compared with the 0.71 g. non-significant response in the absence of supplemental lysine (Table 5) proves that the value of methionine supplementation was dependent upon the presence of added lysine. However, since supplemental lysine plus histidine in the absence of methionine did not give improved N retention it can be concluded that methionine was the first limiting amino acid in the particular feather meal. The absence of response to methionine and/or histidine supplementation as shown in the top half of Table S shows that lysine became limiting before histidine did. Histidine was then the third limiting amino acid in this feather meal and tyrosine evidently the fourth. The significant effect of tyrosine supplementation as shown in Table 3 can be attributed to a significant interaction of the third order (tyrosine gave improved N retention in the presence of lysine, methionine plus h;stidine) which cannot be presented easily in the form of a table. Comparison of three feather meals: Chickens given diets containing any of the three feather meals studied on the average (over all treatments) retained significantly (or in the case of the Canadian feather meal, highly significantly) more N when their diets were supplemented with lysine and
TABLE 6.—N retention of chickens given different feather meals with and without amino acid supplementation in Trial Z Treatment Feather meal
Average N retention/group (given as g. body moisture) Argentinian
Canadian South African
Without lysine With lysine Difference
136.21 138.99 2.78*
148.85 152.87 4.02**
147.64 150.01 2.37*
Without methionine With methionine Difference
136.02 139.18 3.16*
148.55 153.16 4.61**
147.35 150.30 2.95*
Without histidine With histidine Difference
137.80 137.39 -0.41
150.10 151.61 1.51
147.51 150.13 2.62*
* Indicates significance at p <0.05. ** Indicates significance at p <0.01.
Downloaded from http://ps.oxfordjournals.org/ at University of Massachusetts Medical School on April 10, 2015
N o histidine Histidine
Difference
methionine (Table 6). The Argentinian meal, both unsupplemented and supplemented with one, two or all three amino acids, gave highly significantly poorer N retention than the other two meals, while the Canadian meal, supplemented with lysine and methionine only, gave better N retention than the South African meal (p < 0.05). Supplementation with histidine which gave a significant improvement in N retention of chickens given the South African feather meal removed this difference between the two meals. In fact, the interaction between meals and histidine supplementation was statistically significant. The reason for the difference between the South African and Canadian feather meals may be attributable to a small contamination of the latter with blood, which increased its histidine content. The inferiority of the Argentinian meal might be due to a generally lower availability of amino acids in this product, which appeared to have been overheated in processing. The shortage of available methionine in feather meal has been illustrated by Moran et al. (1969) and earlier by workers such as McCasland et al. (1966) and Moran et al. (1966). Both these groups of researchers, using growth of rats or chickens as criterion, found tryptophan supplementation to be beneficial. The South African feather
FEATHER MEALS PROTEIN QUALITY
REFERENCES Bender, A. E., and B. H. Doell, 19S7. Biological evaluation of proteins: a new aspect. Brit. J. Nutr. 11: 140-148. Gehle, M. H., G. M. Speers, D. L. Miller and S. L. Balloun, 1967. Nutritive value of hog hair as a protein source for chicks and poults. Poultry Sci. 46: 156-164. McCasland, W. E., and L. R. Richardson, 1966. Methods for determinining the nutritive value of feather meals. Poultry Sci. 45: 1231-1236. Moran, E. T., W. F. Pepper, and J. D. Summers, 1969. Processed feather and hog hair meals as sources of dietary protein for the laying hen with emphasis on their use in meeting maintenance requirements. Poultry Sci. 48: 12451251. Moran, E. T., J. D. Summers and S. J. Slinger, 1966. Keratin as a source of protein for the growing chick. 1. Amino acid imbalance as the cause for inferior performance of feather meal and the implication of disulphide bonding in raw feathers as the reason for poor digestibility. Poultry Sci. 45: 1257-1266. Naber, E. C , S. P. Touchbum, B. D. Barnett and C. L. Morgan, 1961. Effect of processing method and amino acid supplementation of feather protein on dietary utilization by the chick. Poultry Sci. 40: 1234-1245. Wessels, J. P. H., and M. J. Bundock, 1968. Applicability to chickens of the carcass analysis method for determination of net protein utilization. III. The effect of shorter test period, sex and breed upon the body water-nitrogen relationship in the chicken. S. African J. Agric. Sci. 11: 531-536.
NEWS AND NOTES (Continued from page 536) sity, having edited the O.S.U. veterinary student publication, The Speculum. In 1957, after engaging in general practice in Bellingham, Washington, he became Diiector of Professional Relations for Jensen-Salsbery Laboratories in Kansas City, Missouri. Among his responsibilities was the editing of the Jen-Sal Journal. Since joining the A.V.M.A. staff in 1959, he has been responsible for editing the Journal of the American Veterinary Medical Association, convention proceedings, and proceedings of several special animal disease symposia co-sponsored by A.V.M.A. He is a member of the American Veterinary
Medical Association, the Illinois State Veterinary Medical Association, the Chicago Veterinary Medical Association, the American Society of Veterinary Physiologists and Pharmacologists, U. S. Animal Health Association, the Flying Veterinarians Association, Phi Zeta, and Alpha Psi. HUBBARD NOTES Dr. Thomas F. Savage has been appointed as Geneticist for Hubbard Farms, and assigned to the meat breeder section. He will be working with both basic and applied aspects of the programs involving the White Mountain male and the Hubbard Breeder
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meal was evidently so well processed that less destruction of tryptophan took place than was the case with meals used by these workers. While Moran et al. (1966) claimed that growth depression was completely overcome by supplementation with lysine, methionine and tryptophan, McCasland et al. (1966) only got reasonable growth on supplementation with these three amino acids plus histidine, while Naber et al. (1961) claimed that supplementation with amino acids other than these four was probably necessary for optimum chicken growth when diets contained high levels of feather meal. Their results might have been improved by the addition of tyrosine. Workers have not attempted to arrange amino acids in the order in which they become limiting for chicken growth. Yet Gehle et al. (1967) found lysine and not methionine to be the first limiting amino acid for chicken growth in hydrolysed hot hair (like feather meal a product of keratin hydrolysis). Unsupplemented, the South African meal gave a N.P.TJ. value of 38 in Trial 1 and of 54 when supplemented with the four amino acids methionine, lysine, histidine and tyrosine.
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