METHIONINE HYDROXY ANALOGUE
Velu, J. G., D. H. Baker and H. M. Scott, 1971. Protein and energy utilization by chicks fed graded
591
levels of a balanced mixture of crystalline amino acids. J. Nutr. 101: 1249-1256.
Nonprotein Nitrogen for Growing Chickensi N . TRAKULCHANG AND STANLEY L . BALLOUN
Department of Animal Science, Iowa State University, Ames, Iowa 50010 (Received for publication July 29, 1974)
POULTRY SCIENCE 54: 591-594, 1975
INTRODUCTION
EXPERIMENTAL PROCEDURE
HE extent to which chicks are capable of using nonprotein nitrogen for synthesis of nonessential amino acids is questionable. Lee and Blair (1972) obtained significant increases in weight gains in chicks fed a purified diet adequate in essential amino acids when urea, diammonium citrate or triammonium citrate was added to the diet. Sullivan and Bird (1957) reported improvement of chick growth from urea or diammonium citrate (DAC) supplementation. Featherston et al. (1962) found significant use of urea and DAC by chicks fed a semipurified diet. In contrast, Reid (1967) and Kazemi (1972) obtained growth depression from DAC, and Kazemi and Balloun (1972) showed that percentage nitrogen retention was markedly reduced when urea or DAC was included in the diet. The objective of the present studies was to determine whether young chicks could utilize nonprotein nitrogen fed to supplement low-protein practical diets.
Experiment 1. The basal diet for Experiment 1 was diet A (Table 1). For the other four diets, DAC was added, replacing dextrose, to increase "crude protein" (N x 6.25) to 17 or 19%. Diets containing the two levels of DAC also were fed with lysine, methionine and arginine added to meet N.R.C. (1971) standards. A nitrogen-free diet (Table 1; diet B) was fed to determine endogenous Nexcretion for "apparent N-absorption" and "N-gain" calculation. Chicks were divided into two groups at one week of age. The first group was used to determine nitrogen absorption and nitrogen gain. The arrangement of treatments was a randomized complete block in a split-plot design with batteries as blocks and periods (weeks) as subplots. There were 4 replicate groups of 5 chicks per group for each dietary treatment. The second group of chicks was used for growth rate and feed efficiency studies. The experimental design of this group was similar to that of the first group, except that there were no subplots (periods).
T
1. Journal Paper No. J-7971 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 1932.
Experiment 2. The basal diet in Experiment 2 (Table 1; diet C) was fed in a comparison
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
ABSTRACT Diammonium citrate (DAC) and urea were not used beneficially as nitrogen sources in the diet of young chicks. Supplementation of 0.43% urea to a low-protein practical diet did not significantly affect gain or feed efficiency. Adding 2.85% or 5.70% DAC to a low-protein basal depressed growth and feed efficiency significantly. Percentages of nitrogen intake absorbed and retained by chicks were depressed by DAC. When diets were balanced by added amino acids, DAC did not depress weight gains, but nitrogen percentage retention was still decreased by DAC.
592
N. TRAKULCHANG AND S. L. BALLOUN TABLE 1.—Basal rations
Expt. 1 Basal diet (A) 41.2 23.0
— 2.2 21.8 0.5 0.1 0.5
N-free (%) (B)
— — — 4.5 72.8 0.5
— —
fcxpt. 1 & 5 (%) (C) 70.0 16.2 8.0
— — 0.5 0.1 0.5
—
4.0
—
2.7 1.1 5.9 1.0
— —
2.4 2.3
17.2 1.0
— —
Calculated analyses: 15.1 Crude protein (%) 16.0 0.58 Methionine plus cystine (%) 0.59 — 0.85 0.76 Lysine (%) — 1.00 1.10 Arginine (%) — 3000 3000 M.E. (kcal./kg.) 2950 a Supplied per kg. of diet: vitamin A, 7500 I.U.; vitamin D 3 , 1000 I.C.U.; vitamin E, 10 I.U.; menadione sodium bisulphite, 2.2 mg.; vitamin B 12 , 10 meg.; riboflavin, 5 mg.; choline chloride, 450 mg.; pantothenic acid, 10 mg.; niacin, 25 mg.; ethoxyquin, 100 mg. b Supplied per kg. of diet: NaCl, 4.4 g.; Mn, 117 mg.; Zn, 50 mg.; Fe, 35 mg.; Cu, 6 mg.; I 2 , 2 mg.; Co, 0.55 mg. Supplied per kg. of diet: Ca, 10 g.; P, 6 g.; Na, 1.5 g.; CI, 1.5 g.; K, 4 g.; Mn, 55 mg.; Mg, 550 mg.; Fe, 88 mg.; Cu, 11 mg.; Zn, 45 mg.; Se, 150 meg.; I 2 , 380 meg.; Co, 76 meg. with the same diet with urea added at 2 and 4% protein equivalent. Ninety-six 4-week-old male chicks were used in this experiment, and the arrangement of treatments was a randomized complete-block design with decks in batteries as blocks. Each dietary treatment was assigned to 4 replicate groups, with 8 chicks per group. Experiment 3. Four-week-old male chicks were assigned as in Experiment 2, except that diets in this experiment were supplemented with 50 p.p.m. of 3-nitro-4 hydroxyphenyl-arsonic acid. Data from all experiments were analyzed by methods as described by Steel and Torrie (1960).
RESULTS AND DISCUSSION The data shown in Tables 2 and 3 indicate that, without added amino acids, DAC depressed growth, feed efficiency, nitrogen absorption and nitrogen gain of young chicks significantly. Dietary DAC may have resulted in a rate of ammonium production greater than the rate of production of keto acids from carbohydrates thus causing a high concentration of ammonia in the intestinal tract and blood of chicks. The decrease in nitrogen gain (Table 3) of chicks fed DAC diets also may be a sign of tissue damage due to ammonia toxicity. Because weight gains and feed efficiency were not decreased by added DAC when essential amino acids were made adequate by addition of lysine, methionine
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Ingredients Ground yellow corn Soybean meal (49% protein) Alfalfa meal (17% protein) Soybean oil Dextrose Vitamin premix" Methionine Mineral mixb Mineral mixc Dicalcium phosphate Ground limestone Cellulose Cr 2 0 3
(%)
593
NONPROTEIN NITROGEN
TABLE 2.—Mean weight gain and feed/gain of broiler chicks—Experiment 1'
TABLE 3.—Effects
of DAC and added amino acids on nitrogen absorption and nitrogen gain—Experiment 1' Age (weeks) 2
5
4
3
Mean
apparent nitrogen absorpt ion (%)
Dietary treatments 1. 2. 3. 4. 5.
Basal A, Table 1 1 plus 2.85% DAC 1 plus 5.70% DAC 2 plus amino acids 2 3 plus amino acids 2
80.2 61.7 57.4 68.6 59.0
1. 2. 3. 4. 5.
Basal A, Table 1 1 plus 2.85% DAC 1 plus 5.70% DAC 2 plus amino acids 2 3 plus amino acids 2
68.2 52.0 47.8 59.5 48.6
80.4 56.5 61.8 78.6 69.9
76.3 68.5 66.2 75.5 67.7
76.7 65.7 60.0 71.6 61.0
nitrogen gain (% of diet niitrogen) 57.5 61.1 60.1 41.5 49.4 48.9 49.8 44.2 48.5 57.3 56.7 51.4 52.7 51.0 49.1
78.4 63.1 61.4 73.6 64.4
a b b a b
61.7 48.0 47.6 56.2 50.4
a c c ab be
'All values represent means of 4 replicate groups, 5 birds per group. Values in a column, not followed by a common letter are significantly different (P < 0.05). 2 Lysine 0.24%; Methionine 0.24%; Arginine 0.29%.
TABLE 4.— The effects of urea on weight gain and feed efficiency of broilers 4-8 weeks of age—Experiments 2 and 3' Experiment 2 Dietary treatments Basal diet Basal + 0.43% urea Basal + 0.86% urea
Experiment 3 2
Av. wt. gain (g.)
Feed/gain
Av. wt. gain (g.)
Feed/gain
939 934 931
2.66 2.70 2.80
900 953 913
2.78 2.83 2.76
'All values are means of 4 replicate groups of 8 chicks per group. Diets in Experiment 3 contained 50 p.p.m. of 3-nitro-4-hydroxyphenylarsonic acid.
2
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Av. weight gain (g.) Feed/gain Dietary (1 to 5 (1 to 5 weeks) treatments weeks) 1. Basal A, Table 1 731 a 2.33 b 2. 1 plus 2.85% DAC 588 b 2.52 c 3. 1 plus 5.70% DAC 523 c 2.57 c 4. 2 plus amino acids2 722 a 2.19 a 5. 3 plus amino acids2 739 a 2.13 a ' All values represent means of 4 replicate groups; 5 birds per group. Values in a column not followed by a common superscript letter are significantly different (P < 0.05). 2 Lysine 0.24%; Methionine 0.24%; Arginine 0.29%.
and arginine, some kind of "protective action" may be ascribed to this supplementation. The percentage of diet nitrogen retained by chicks fed diets with added DAC was significantly less than that retained by chicks fed the basal diet. Two experiments were conducted with chicks 4 to 8 weeks of age to evaluate urea as a nonprotein source for chicks (Table 4). Diets fed (Table 1) were low-protein (16%) practical diets with methionine added. Urea was added at 0.43 and 0.86% to 2 and 4% crude protein equivalent to the basal diet. No significant improvements in weight gains or feed efficiency were caused by added
594
N. TRAKULCHANG AND S. L. BALLOUN
nitrogen from urea to the low-protein diet. In Experiment 3, some improved gains were observed and
might indicate a
tendency
toward a reduced rate of ammonia release from urea when intestinal microbial activity was reduced by 3-nitro-phenyl arsonic acid. REFERENCES
Effect of Filtering Recycled Air in a Chick Hatcher on Airborne Pathogenic Microorganisms1,2 JOHN S. AVENS, CAREY L. QUARLES AND DIANE J. FAGERBERG
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication July 29, 1974)
ABSTRACT Two experimental chick hatchers in which ventilation air within the hatcher was partially recirculated in a positive pressure system, one with an air filter in the system and the other without a filter, were simultaneously tested to determine effect of the filter on quantitative reduction of viable airborne microorganisms. Chicks were artificially contaminated with either Escherichia coli or Staphylococcus aureus (coagulase-positive). Air was sampled for total test bacteria per cubic foot of hatcher air. The filter effectively reduced the number of viable airborne particles contaminated with E. coli and S. aureus contributed by chicks in the hatcher. POULTRY SCIENCE 54: 594-599, 1975
INTRODUCTION
M
various other airborne particles which are
ICROORGANISMS on or in a few
prevalent in the hatcher a few hours before
hatching
the hatch is completed. Pathogenic Escher-
eggs
can
be
throughout the hatcher by air
distributed movement
ichia coli -contaminated eggs can account for
during hatching and thus contaminate or in-
extensive
fect all other chicks in the machine. Microor-
conditions, i.e.,
chick mortality.
ganisms may be carried on chick down and
Staphylococcus
injury,
Under
some
certain
strains
of
aureus may cause acute or
chronic disease to chicks. Magwood (1964) observed a direct relationship between air1. Published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series paper number 1991. 2. This research was supported in part by Robbins Incubator Company, Project 6535.
borne microorganisms and the amount of contamination of various hatchery surfaces. If the amount of airborne particles carrying microorganisms could be significantly
re-
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Featherston, W. R., H. R. Bird and A. E. Harper, 1962. Ability of the chick to utilize D- and excess L-indispensable amino acid nitrogen in the synthesis of dispensable amino acids. J. Nutr. 78: 95-100. Kazemi, R. S., 1972. Urea and diammonium citrate utilization by poultry. Ph.D. Thesis, Iowa State University, Department of Animal Science, Ames, Iowa. Kazemi, R., and S. L. Balloun, 1972. Effect of urea
and diammonium citrate on fecal components of chicken hens. Poultry Sci. 51: 1480-1481. Lee, D. J. W., and R. Blair, 1972. Effects on chick growth of adding various nonprotein nitrogen sources or dried autoclaved poultry manure to diets containing crystalline essential amino acids. Br. Poultry Sci. 13: 243-249. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences, Washington, D.C. Reid, B. L., 1967. Nonprotein nitrogen studies with poultry. Georgia Nutr. Conf. Proc. 1967: 73-81. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York. Sullivan, T. W., and H. R. Bird, 1957. Effect of the quality and source of dietary nitrogen on the utilization of the hydroxy analogues of methionine and glycine by chicks. J. Nutr. 62: 143-150.
Velu, J. G., D. H. Baker and H. M. Scott, 1971. Protein and energy utilization by chicks fed graded
591
levels of a balanced mixture of crystalline amino acids. J. Nutr. 101: 1249-1256.
Nonprotein Nitrogen for Growing Chickensi N . TRAKULCHANG AND STANLEY L . BALLOUN
Department of Animal Science, Iowa State University, Ames, Iowa 50010 (Received for publication July 29, 1974)
POULTRY SCIENCE 54: 591-594, 1975
INTRODUCTION
EXPERIMENTAL PROCEDURE
HE extent to which chicks are capable of using nonprotein nitrogen for synthesis of nonessential amino acids is questionable. Lee and Blair (1972) obtained significant increases in weight gains in chicks fed a purified diet adequate in essential amino acids when urea, diammonium citrate or triammonium citrate was added to the diet. Sullivan and Bird (1957) reported improvement of chick growth from urea or diammonium citrate (DAC) supplementation. Featherston et al. (1962) found significant use of urea and DAC by chicks fed a semipurified diet. In contrast, Reid (1967) and Kazemi (1972) obtained growth depression from DAC, and Kazemi and Balloun (1972) showed that percentage nitrogen retention was markedly reduced when urea or DAC was included in the diet. The objective of the present studies was to determine whether young chicks could utilize nonprotein nitrogen fed to supplement low-protein practical diets.
Experiment 1. The basal diet for Experiment 1 was diet A (Table 1). For the other four diets, DAC was added, replacing dextrose, to increase "crude protein" (N x 6.25) to 17 or 19%. Diets containing the two levels of DAC also were fed with lysine, methionine and arginine added to meet N.R.C. (1971) standards. A nitrogen-free diet (Table 1; diet B) was fed to determine endogenous Nexcretion for "apparent N-absorption" and "N-gain" calculation. Chicks were divided into two groups at one week of age. The first group was used to determine nitrogen absorption and nitrogen gain. The arrangement of treatments was a randomized complete block in a split-plot design with batteries as blocks and periods (weeks) as subplots. There were 4 replicate groups of 5 chicks per group for each dietary treatment. The second group of chicks was used for growth rate and feed efficiency studies. The experimental design of this group was similar to that of the first group, except that there were no subplots (periods).
T
1. Journal Paper No. J-7971 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project 1932.
Experiment 2. The basal diet in Experiment 2 (Table 1; diet C) was fed in a comparison
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
ABSTRACT Diammonium citrate (DAC) and urea were not used beneficially as nitrogen sources in the diet of young chicks. Supplementation of 0.43% urea to a low-protein practical diet did not significantly affect gain or feed efficiency. Adding 2.85% or 5.70% DAC to a low-protein basal depressed growth and feed efficiency significantly. Percentages of nitrogen intake absorbed and retained by chicks were depressed by DAC. When diets were balanced by added amino acids, DAC did not depress weight gains, but nitrogen percentage retention was still decreased by DAC.
592
N. TRAKULCHANG AND S. L. BALLOUN TABLE 1.—Basal rations
Expt. 1 Basal diet (A) 41.2 23.0
— 2.2 21.8 0.5 0.1 0.5
N-free (%) (B)
— — — 4.5 72.8 0.5
— —
fcxpt. 1 & 5 (%) (C) 70.0 16.2 8.0
— — 0.5 0.1 0.5
—
4.0
—
2.7 1.1 5.9 1.0
— —
2.4 2.3
17.2 1.0
— —
Calculated analyses: 15.1 Crude protein (%) 16.0 0.58 Methionine plus cystine (%) 0.59 — 0.85 0.76 Lysine (%) — 1.00 1.10 Arginine (%) — 3000 3000 M.E. (kcal./kg.) 2950 a Supplied per kg. of diet: vitamin A, 7500 I.U.; vitamin D 3 , 1000 I.C.U.; vitamin E, 10 I.U.; menadione sodium bisulphite, 2.2 mg.; vitamin B 12 , 10 meg.; riboflavin, 5 mg.; choline chloride, 450 mg.; pantothenic acid, 10 mg.; niacin, 25 mg.; ethoxyquin, 100 mg. b Supplied per kg. of diet: NaCl, 4.4 g.; Mn, 117 mg.; Zn, 50 mg.; Fe, 35 mg.; Cu, 6 mg.; I 2 , 2 mg.; Co, 0.55 mg. Supplied per kg. of diet: Ca, 10 g.; P, 6 g.; Na, 1.5 g.; CI, 1.5 g.; K, 4 g.; Mn, 55 mg.; Mg, 550 mg.; Fe, 88 mg.; Cu, 11 mg.; Zn, 45 mg.; Se, 150 meg.; I 2 , 380 meg.; Co, 76 meg. with the same diet with urea added at 2 and 4% protein equivalent. Ninety-six 4-week-old male chicks were used in this experiment, and the arrangement of treatments was a randomized complete-block design with decks in batteries as blocks. Each dietary treatment was assigned to 4 replicate groups, with 8 chicks per group. Experiment 3. Four-week-old male chicks were assigned as in Experiment 2, except that diets in this experiment were supplemented with 50 p.p.m. of 3-nitro-4 hydroxyphenyl-arsonic acid. Data from all experiments were analyzed by methods as described by Steel and Torrie (1960).
RESULTS AND DISCUSSION The data shown in Tables 2 and 3 indicate that, without added amino acids, DAC depressed growth, feed efficiency, nitrogen absorption and nitrogen gain of young chicks significantly. Dietary DAC may have resulted in a rate of ammonium production greater than the rate of production of keto acids from carbohydrates thus causing a high concentration of ammonia in the intestinal tract and blood of chicks. The decrease in nitrogen gain (Table 3) of chicks fed DAC diets also may be a sign of tissue damage due to ammonia toxicity. Because weight gains and feed efficiency were not decreased by added DAC when essential amino acids were made adequate by addition of lysine, methionine
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Ingredients Ground yellow corn Soybean meal (49% protein) Alfalfa meal (17% protein) Soybean oil Dextrose Vitamin premix" Methionine Mineral mixb Mineral mixc Dicalcium phosphate Ground limestone Cellulose Cr 2 0 3
(%)
593
NONPROTEIN NITROGEN
TABLE 2.—Mean weight gain and feed/gain of broiler chicks—Experiment 1'
TABLE 3.—Effects
of DAC and added amino acids on nitrogen absorption and nitrogen gain—Experiment 1' Age (weeks) 2
5
4
3
Mean
apparent nitrogen absorpt ion (%)
Dietary treatments 1. 2. 3. 4. 5.
Basal A, Table 1 1 plus 2.85% DAC 1 plus 5.70% DAC 2 plus amino acids 2 3 plus amino acids 2
80.2 61.7 57.4 68.6 59.0
1. 2. 3. 4. 5.
Basal A, Table 1 1 plus 2.85% DAC 1 plus 5.70% DAC 2 plus amino acids 2 3 plus amino acids 2
68.2 52.0 47.8 59.5 48.6
80.4 56.5 61.8 78.6 69.9
76.3 68.5 66.2 75.5 67.7
76.7 65.7 60.0 71.6 61.0
nitrogen gain (% of diet niitrogen) 57.5 61.1 60.1 41.5 49.4 48.9 49.8 44.2 48.5 57.3 56.7 51.4 52.7 51.0 49.1
78.4 63.1 61.4 73.6 64.4
a b b a b
61.7 48.0 47.6 56.2 50.4
a c c ab be
'All values represent means of 4 replicate groups, 5 birds per group. Values in a column, not followed by a common letter are significantly different (P < 0.05). 2 Lysine 0.24%; Methionine 0.24%; Arginine 0.29%.
TABLE 4.— The effects of urea on weight gain and feed efficiency of broilers 4-8 weeks of age—Experiments 2 and 3' Experiment 2 Dietary treatments Basal diet Basal + 0.43% urea Basal + 0.86% urea
Experiment 3 2
Av. wt. gain (g.)
Feed/gain
Av. wt. gain (g.)
Feed/gain
939 934 931
2.66 2.70 2.80
900 953 913
2.78 2.83 2.76
'All values are means of 4 replicate groups of 8 chicks per group. Diets in Experiment 3 contained 50 p.p.m. of 3-nitro-4-hydroxyphenylarsonic acid.
2
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Av. weight gain (g.) Feed/gain Dietary (1 to 5 (1 to 5 weeks) treatments weeks) 1. Basal A, Table 1 731 a 2.33 b 2. 1 plus 2.85% DAC 588 b 2.52 c 3. 1 plus 5.70% DAC 523 c 2.57 c 4. 2 plus amino acids2 722 a 2.19 a 5. 3 plus amino acids2 739 a 2.13 a ' All values represent means of 4 replicate groups; 5 birds per group. Values in a column not followed by a common superscript letter are significantly different (P < 0.05). 2 Lysine 0.24%; Methionine 0.24%; Arginine 0.29%.
and arginine, some kind of "protective action" may be ascribed to this supplementation. The percentage of diet nitrogen retained by chicks fed diets with added DAC was significantly less than that retained by chicks fed the basal diet. Two experiments were conducted with chicks 4 to 8 weeks of age to evaluate urea as a nonprotein source for chicks (Table 4). Diets fed (Table 1) were low-protein (16%) practical diets with methionine added. Urea was added at 0.43 and 0.86% to 2 and 4% crude protein equivalent to the basal diet. No significant improvements in weight gains or feed efficiency were caused by added
594
N. TRAKULCHANG AND S. L. BALLOUN
nitrogen from urea to the low-protein diet. In Experiment 3, some improved gains were observed and
might indicate a
tendency
toward a reduced rate of ammonia release from urea when intestinal microbial activity was reduced by 3-nitro-phenyl arsonic acid. REFERENCES
Effect of Filtering Recycled Air in a Chick Hatcher on Airborne Pathogenic Microorganisms1,2 JOHN S. AVENS, CAREY L. QUARLES AND DIANE J. FAGERBERG
Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication July 29, 1974)
ABSTRACT Two experimental chick hatchers in which ventilation air within the hatcher was partially recirculated in a positive pressure system, one with an air filter in the system and the other without a filter, were simultaneously tested to determine effect of the filter on quantitative reduction of viable airborne microorganisms. Chicks were artificially contaminated with either Escherichia coli or Staphylococcus aureus (coagulase-positive). Air was sampled for total test bacteria per cubic foot of hatcher air. The filter effectively reduced the number of viable airborne particles contaminated with E. coli and S. aureus contributed by chicks in the hatcher. POULTRY SCIENCE 54: 594-599, 1975
INTRODUCTION
M
various other airborne particles which are
ICROORGANISMS on or in a few
prevalent in the hatcher a few hours before
hatching
the hatch is completed. Pathogenic Escher-
eggs
can
be
throughout the hatcher by air
distributed movement
ichia coli -contaminated eggs can account for
during hatching and thus contaminate or in-
extensive
fect all other chicks in the machine. Microor-
conditions, i.e.,
chick mortality.
ganisms may be carried on chick down and
Staphylococcus
injury,
Under
some
certain
strains
of
aureus may cause acute or
chronic disease to chicks. Magwood (1964) observed a direct relationship between air1. Published with the approval of the Director of the Colorado State University Experiment Station as Scientific Series paper number 1991. 2. This research was supported in part by Robbins Incubator Company, Project 6535.
borne microorganisms and the amount of contamination of various hatchery surfaces. If the amount of airborne particles carrying microorganisms could be significantly
re-
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis Dept S on March 17, 2015
Featherston, W. R., H. R. Bird and A. E. Harper, 1962. Ability of the chick to utilize D- and excess L-indispensable amino acid nitrogen in the synthesis of dispensable amino acids. J. Nutr. 78: 95-100. Kazemi, R. S., 1972. Urea and diammonium citrate utilization by poultry. Ph.D. Thesis, Iowa State University, Department of Animal Science, Ames, Iowa. Kazemi, R., and S. L. Balloun, 1972. Effect of urea
and diammonium citrate on fecal components of chicken hens. Poultry Sci. 51: 1480-1481. Lee, D. J. W., and R. Blair, 1972. Effects on chick growth of adding various nonprotein nitrogen sources or dried autoclaved poultry manure to diets containing crystalline essential amino acids. Br. Poultry Sci. 13: 243-249. National Research Council, 1971. Nutrient requirements of poultry. National Academy of Sciences, Washington, D.C. Reid, B. L., 1967. Nonprotein nitrogen studies with poultry. Georgia Nutr. Conf. Proc. 1967: 73-81. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Company, Inc., New York. Sullivan, T. W., and H. R. Bird, 1957. Effect of the quality and source of dietary nitrogen on the utilization of the hydroxy analogues of methionine and glycine by chicks. J. Nutr. 62: 143-150.
