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Genotype × Dietary Protein Level Interactions in Egg Production Stocks
Genotype X Dietary Protein Level Interactions in Egg Production Stocks J. R. AlTKEN, J . BlELY, N . NlKOLAICZUK, A. R. RoBBLEE, J. D . SUMMERS AND W. K. B A R R 1
Animal Research Institute, Canada Department of Agriculture, Ottawa*, Ontario, Canada (Received for publication January 12, 1972)
POULTRY SCIENCE 51: 1578-1582,1972
INTRODUCTION
U
N T I L a few years ago, the large number of egg production stocks available to producers, coupled with t h e rate at which breeders were developing and improving their birds, made it impractical to characterize strains in terms of their nutritional requirements. Over t h e past decade, this situation has changed. There has been a rapid decline in the number of strains offered for sale, and performance levels have been approaching a plateau. These circumstances have made it feasible to consider tailoring t h e diet to suit t h e strain of bird, and hence there h a s been increasing interest in dietary requirements as they differ between strains. Attention has naturally been focussed on protein as t h e most costly nutrient other than energy, b u t the importance of differences in protein requirements among 1 Affiliation of authors in the order named: Canada Department of Agriculture, Ottawa; University of British Columbia, Vancouver; Macdonald College, Quebec; University of Alberta, Edmonton; University of Guelph, Guelph, Ontario; Canada Department of Agriculture, Ottawa. 2 Contribution No. 439, Animal Research Institute.
commercial egg production strains remains open t o question. Some workers have found significant genotype X dietary protein level interactions for a number of performance traits (Harms and Waldroup, 1962; Moreng et al., 1964; Deaton and Quisenberry, 1965; H a r m s et al., 1966), whereas others have not (Marks et al., 1969). I n t h e present study, advantage was taken of the opportunity to conduct a trial on t h e 17 strains entered in t h e Canadian R a n d o m Sample Egg Production Test b y feeding two diets, one which had previously been shown to be adequate in protein content and one which was calculated t o be marginal. MATERIALS AND METHODS Seventeen egg production stocks were obtained as hatching-eggs and incubated on t h e R a n d o m Sample Test premises. The stocks comprised one control strain, two experimental strains and 14 commercial strains. Six of t h e commercial strains were obtained from breeders with international franchises, and 8 from breeders distributing within Canada. The pullets were reared in 68 floor pens, segregated b y strain, on a common feed-
1578
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
ABSTRACT Two diets, one adequate in protein (17.0%) and one marginal (14.5%), were fed to the 17 egg production strains entered in the Canadian Random Sample Test. The purpose was to test for the presence of genotypeX dietary protein level interactions, using egg production, egg weight, final body weight, feed consumption, mortality and egg quality as performance criteria. There were two floor pens totalling approximately 120 birds per strain on each diet. Duration of the test was 350 days. The low protein diet resulted in lower egg production, mean egg weight, final body weight and albumin quality. Significant genotypeXdietary protein level interactions were observed for egg weight, albumin quality and feed consumption. The significance of these findings is discussed.
1579
P R O T E I N INTERACTIONS
TABLE 2.—Ntiltient composition of diets Control Diet Mean Crude protein (%) 17.0 Ether extract (%) 3.7 Crude fibre (%) 3.2 Calcium (%) 2.9 Phosphorus (%) 0.70 Metaboliable energy (kcal./ kg.)> 2890 1
Ingredient
(Control Diet
Low Protein Diet
%
%
Corn 36 35.25 Wheat 2.75 Stabilized tallow Soybean meal (50% protein) 15.5 Dehydrated alfalfa meal 2 6.25 Ground limestone 1.5 Dicalcium phosphate 0.25 Iodized salt 1 0.5 Micro-nutrients
40.8 40.05 1.55 7 2 6.25 1.6 0.25 0.5
1 Micro-nutrients added per kg. of feed Vitamin A (i.u.) 6300 Menadione Na biVitamin D 3 (i.c.u.) 1040 sulphite (mg.) 1.1 Vitamin B !2 (Mg.) 44 DL-methionine Choline Chloride (mg.) 500 (mg.) 125 Manganese (mg.) 30 Riboflavin (mg.) 3.3 Zinc (mg.) 30
Range
Mean
Range
15.2-19.1 2.9-4.2 2.4-3.8 2.3-3.4 0.6-0.7
14.5 3.4 3.1 2.7 0.65
13.2-15.3 2.4-4.2 2.4-3.9 2.0-3.2 0.6-0.8
2890
Calculated values.
egg production, feed consumption a n d body weight records were maintained on a pen basis. Two days eggs per pen per week were mass weighed and graded for size and quality according to official Canadian standards. Once every 28 days, 25 eggs per pen were taken for determination of specific gravity, albumin height and Haugh unit score. All performance traits were subjected to analysis of variance, following the model shown in Table 3, in which diets were considered a fixed effect, and genotypes as random. Cochran's approximate method was used to calculate F ratios for testing diets (Cochran and Cox,, 1957). RESULTS AND DISCUSSION
Throughout the 350-day test period, TABLE 1.—Composition of diets
Low Protein Diet
Nutrient
Diets. T h e split plot design used in this experiment provided a high degree of sensitivity for testing t h e significance of strain X diet interactions and strain differences, which were the points of major concern. T h e design was also chosen because it suited the laying house facility, and it simplified operations to feed a SUITABLE 3.—Analysis of variance
Diets (D) Between quadrants treated alike (Q) Genotypes (G) GenotypesXDiets
Error
1 o-Q2-|-o-GD2-|-17
16 O-E2+2<;O2 16 O-E2+O-GD2
32 O-E2
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
ing a n d management regime. A t 21 weeks of age they were transferred as pen units to the laying quarters. Each strain was represented b y a pen of birds located at random within each quadrant of t h e laying house. Pen size was 4 X 5 . 5 meters, a n d t h e number of birds per pen ranged from 57 to 69. The two diets (Table 1) were fed in diagonally opposite quadrants, which provided two pens per strain on each diet. T h e control diet h a d been tested a n d found adequate over two previous years {Aitken et al., 1969), whereas the second diet was formulated to be marginal in protein content, in t h e expectation t h a t it would reveal differences between genotypes without unduly depressing mean performance levels. Both diets h a d t h e same calculated metabolizable energy value of 2890 kcal./kg. T h e feeds were custom mixed b y a commercial company, which made deliveries at approximately 3 week intervals. Each mix was sampled and chemically analyzed for crude protein, ether extract, crude fibre, calcium and phosphorus (Table 2).
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AlTKEN, BlELY, NlKOLAICZUK, R.OBBLEE, SUMMERS AND BARR TABLE 4.—Performance over 350 days as influenced by diet Low Protein Diet
Control Diet
Trait
12.5 2189
13.2 2128
Egg production Per hen housed (No.) Per hen day X 100
219.6 67.2
211.3 64.9
116.S 2090 2.93
115.3 2141 •3.03
Feed consumption Per bird day (g.) Per dozen eggs (g.) Per unit weight of eggs Egg size and quality Mean egg weight (g.) Large+extra large eggs (%) Specific gravity Albumin height (mm.) Haugh unit score Grade B eggs (%)
59.5 65.9 1.082 5.66 72.6 3.6
58.9 61.4 1.082 5.54 71.8 4.2
gle diet in each quadrant. One disadvantage was the large whole plot error variance associated with diets, so that differences between diets were not statistically significant. However, the diet compariT A B L E ; 5.—Laying
Stocks. The stocks spanned as'" wide a range in level of production and body size as one would expect to encounter among commercial strains. Therefore, it is not surprising that statistical analysis revealed highly significant (P<0.01) differences among stocks in all performance traits. Four of the more important mea-
house performance (4 traits) presented by strain and diet Low ]protein diet. Relative values.1
Control diet. Absolute values Strain No.
Feed per Egg production bird day g%
Egg weight g-
Final body weight kg-
Feed per Egg production bird day
Egg weight
Final body weight
5 13 15 7 16 14 6 4 2 1 3 17 8 10 11 9 12
74.5 73.7 73.7 72.3 70.7 70.5 68.3 67.3 66.8 64.8 64.6 64.6 63.9 62.9 62.4 61.9 59.3
123.1 113.1 123.1 111.6 127.4 117.8 115.2 111.5 110.5 112.5 125.3 114.0 110.4 112.1 109.8 111.5 130.9
62.3 59.0 60.0 59.9 60.3 62.3 58.6 58.8 58.4 58.3 58.7 59.0 59.3 58.8 58.9 57.7 61.3
2.29 2.00 2.00 1.95 2.45 1.84 2.11 1.97 1.90 2.11 2.81 2.02 2.11 2.29 2.22 2.27 2.84
92.9 92.5 97.4 96.3 93.6 90.5 96.8 97.8 95.8 105.2* 100.9* 94.7 99.1 96.5 99.5 100.0* 95.4
102.3 93.7 94.7* 99.7 96.9 98.3 98.9 101.5 92.3* 98.5* 98.0* 97.8 100.6 104.5 103.7 104.0 98.0
99.2 93.6 97.8 98.7 98.9 100.0* 101.3* 99.6 94.0 98.4 102.2* 99.6 99.0 100.5* 99.8 101.1* 98.2
96.0 93.2 100.0* 97.7 96.3 95.1 97.8 97.7 90.5 97.8 96.8 102.3* 100.0* 98.0 97.8 98.0 98.4
Combined
67.2
116.5
59.5
2.18
96.6
98.9
98.9
97.9
1
Value for low protein dietX 100/corresponding value for control diet. * Cases where the birds did not respond in the expected manner to the low protein diet.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
Mortality (%) Final body weight (g.)
sons shown in Tables 4 and 5 suggest that there were probably true differences between the diets in a number of performance traits, had the test been designed to reveal them. Egg production, egg weight, final body weight and feed consumption were all lower on the marginal protein diet over all strains combined (Table 4), and were also lower for the majority of the strains when these were compared individually (Table 5). Traits which did not appear to be influenced by the diet were percent mortality and specific gravity of the eggs, but albumin quality was slightly superior on the control diet.
P R O T E I N INTERACTIONS
sures of performance are shown according to strain and diet in Table 5. To facilitate comparisons, the figures have been presented in absolute terms for the control diet, and in relative terms (low protein dietXIOO/control diet) for the low protein diet.
To illustrate this point, the manner in which the individual strains responded to the low protein diet is shown in some detail in Table 5. K r a u t m a n n (1969) points out t h a t a number of response mechanisms can come into play when laying hens are fed a diet which is marginal to requirements in protein content. The birds can reduce rate of egg production, or egg size, or body weight gains, or they can increase feed consumption beyond caloric require-
ments in an a t t e m p t to obtain more protein. Some or all of these mechanisms can be used in varying degrees in a manner characteristic of the particular strain. I n the present case, 3 of the strains did not respond to the low protein diet with the expected reduction in egg production, 5 did not reduce egg size, and 3 did not decrease body weight. At first glance, it might appear t h a t only 6 of the 17 strains increased feed consumption on the low protein diet, b u t in 7 of the remaining strains the drop in feed consumption was less than the corresponding drop in egg production. Hence only 4 strains deviated from the expected response and actually decreased feed consumption in relation to rate of egg production. T h e general conclusion from this study is t h a t genotype X dietary protein level interactions among egg production stocks tend to be the exception rather than the rule, b u t two factors come to mind which might explain discrepancies in the results of different investigators. The first concerns the type of diets used. Where a diet adequate in protein is compared with one which is severely deficient, one might expect strain differences to be magnified as compared with a case in which the adequate diet is compared with one which is marginal or only slightly deficient in protein. The second factor concerns the number of strains under test. If it happens t h a t most strains are similar in their protein requirements, the influence of an exceptional strain will be more apparent when it forms p a r t of a small population of strains than when it is p a r t of a large one. REFERENCES Aitken, J. R., J. Biely, N. Nikolaiczuk, A. R. Robblee and S. J. SHnger, 1969. Comparison of laying rations with and without animal protein at the Canadian random sample egg production test. Brit. Poultry Sci. 10: 247-253. Cochran, W. G., and G. M. Cox, 1957. Experimental
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Interactions. The only genotype X diet interactions which proved to be statistically significant were for egg weight and albumin quality ( P < 0 . 0 1 ) and for feed consumption ( P < 0 . 0 5 ) . In the other performance traits, notably egg production, most of the strains in the population under study appear to have responded in approximately the same manner to a diet marginal in protein content. However, this does not permit us to conclude t h a t in egg production, for example, there were no strains in the population which differed significantly in their response to the low protein diet. Where the number of strains under test is relatively large, and where the majority behave in approximately the same manner, the presence of a few strains which deviate considerably from the norm can be masked. Tests of the present type are more appropriate for estimating the importance of genotype X dietary protein level interactions in the population of strains considered as a whole, than for detecting the presence of individual strains which respond differently from one another.
1581
1582
AlTKEN, BlELY, NlKOLAICZUK, ROBBLEE, SUMMERS AND BARR Krautmann, B. A., 1969. Strain interactions to marginal protein and amino acid diets. Poultry Sci. 48: 1831-1832. Marks, H. L., N. R. Gyles, H. R. Wilson, L. D. Tindell, W. A. Johnson, L. J. Dreesen, W. L. Blow, W. F. Krueger and P. B. Siegel, 1969. Genotype-environment interactions in egg production stocks of chickens. 2. Main effects and interactions of stock, protein, year and location. Poultry Sci. 48: 1070-1081. Moreng, R. E., H. L. Enos, W. A. Whittet and B. F. Miller, 1964. An analysis of strain response to dietary protein levels. Poultry Sci. 43: 630-638.
Safety and Toxicity of Oietary Organic Arsenicals Relative to Performance of Young Turkeys 3. NITARSONE 1 ' 2 T. W. SULLIVAN AND ALI A. AI.-TIMIMI Department of Poultry Science, University of Nebraska, Lincoln, Nebraska 68503 (Received for publication January 13, 1972) ABSTRACT Two experiments were conducted with Large White turkeys from day-old to 28 days of age. Nitarsone (4-nitrophenylarsonic acid) levels from 0.01 to 0.08 percent were fed in a ground yellow corn-soybean meal, basal diet containing 28% protein. Body weight of individual birds and the feed consumption of each experimental group were recorded at the end of 14 and 28 days. Birds were closely observed daily for toxicity symptoms and mortality. Percent tibia ash was determined at 28 days in the first experiment. The maximum safe dietary level of nitarsone relative to performance of young turkeys to 28 days of age was 0.02 percent in both experiments. Body weight gain to 28 days was significantly decreased (P<0.01) in poults fed 0.03 percent of the drug. Mortality was 11.1, 55.6, 54.2 and 100%, respectively, among poults fed 0.04, 0.05, 0.06 and 0.08 percent of nitarsone. Therefore, the dietary drug level necessary to cause 50 percent mortality in turkeys to 28 days (L.D. 50/28) was about 0.05 percent. Symptoms of nitarsone toxicity appeared during the second week and included: leg weakness, a tendency to sit, head tremors with eyes closed, some paralysis and loss of appetite. Percent tibia ash was significantly (P<0.05) increased when nitarsone (0.02, 0.04, or 0.06 percent) was present in the diet. POULTRY SCIENCE 5 1 : 1582-1586,
INTRODUCTION
N
ITARSONE or 4-nitrophenylarsonic acid is an organic arsenical compound used in poultry diets as an aid in prevention of infectious enterohepatitis or histomoniasis (blackhead disease). The approved level for this usage was formerly 0.025 percent but is presently 1 Published as Paper Number 3320, Journal series, Nebraska Agricultural Experiment Station. i2 From a thesis submitted by the junior author in partial fulfillment of the requirement for the Ph.D. degree.
1972
0.01875 percent of the diet (Feed Additive Compendium, 1971). Reports concerning the effect of nitarsone on body weight gain and feed efficiency are somewhat contradictory. McGuire and Morehouse (1952) reported 10.8 and 3.7 percent greater body weight gains in poults receiving 0.0066 and 0.05 percent of dietary nitarsone, respectively. Slinger et al. (1954), while studying the value of nitarsone (0.025%) for prevention of perosis in turkeys, observed a significant body weight depression. Sullivan
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
Designs. Second Edition. John Wiley and Sons, New York. p. 467. Deaton, J. W., and J. H. Quisenberry, 1965. Effects of dietary protein level on performance of four commercial egg production stocks. Poultry Sci. 44: 936-942. Harms, R. H., and P. W. Waldroup, 1962. Strain differences in the protein requirement of laying hens. Poultry Sci. 41: 1985-1987. Harms, R. H., B. L. Damron and P. W. Waldroup, 1966. Influence of strain or breed upon the protein requirement of laying hens. Poultry Sci. 45: 272-275.
Animal Research Institute, Canada Department of Agriculture, Ottawa*, Ontario, Canada (Received for publication January 12, 1972)
POULTRY SCIENCE 51: 1578-1582,1972
INTRODUCTION
U
N T I L a few years ago, the large number of egg production stocks available to producers, coupled with t h e rate at which breeders were developing and improving their birds, made it impractical to characterize strains in terms of their nutritional requirements. Over t h e past decade, this situation has changed. There has been a rapid decline in the number of strains offered for sale, and performance levels have been approaching a plateau. These circumstances have made it feasible to consider tailoring t h e diet to suit t h e strain of bird, and hence there h a s been increasing interest in dietary requirements as they differ between strains. Attention has naturally been focussed on protein as t h e most costly nutrient other than energy, b u t the importance of differences in protein requirements among 1 Affiliation of authors in the order named: Canada Department of Agriculture, Ottawa; University of British Columbia, Vancouver; Macdonald College, Quebec; University of Alberta, Edmonton; University of Guelph, Guelph, Ontario; Canada Department of Agriculture, Ottawa. 2 Contribution No. 439, Animal Research Institute.
commercial egg production strains remains open t o question. Some workers have found significant genotype X dietary protein level interactions for a number of performance traits (Harms and Waldroup, 1962; Moreng et al., 1964; Deaton and Quisenberry, 1965; H a r m s et al., 1966), whereas others have not (Marks et al., 1969). I n t h e present study, advantage was taken of the opportunity to conduct a trial on t h e 17 strains entered in t h e Canadian R a n d o m Sample Egg Production Test b y feeding two diets, one which had previously been shown to be adequate in protein content and one which was calculated t o be marginal. MATERIALS AND METHODS Seventeen egg production stocks were obtained as hatching-eggs and incubated on t h e R a n d o m Sample Test premises. The stocks comprised one control strain, two experimental strains and 14 commercial strains. Six of t h e commercial strains were obtained from breeders with international franchises, and 8 from breeders distributing within Canada. The pullets were reared in 68 floor pens, segregated b y strain, on a common feed-
1578
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
ABSTRACT Two diets, one adequate in protein (17.0%) and one marginal (14.5%), were fed to the 17 egg production strains entered in the Canadian Random Sample Test. The purpose was to test for the presence of genotypeX dietary protein level interactions, using egg production, egg weight, final body weight, feed consumption, mortality and egg quality as performance criteria. There were two floor pens totalling approximately 120 birds per strain on each diet. Duration of the test was 350 days. The low protein diet resulted in lower egg production, mean egg weight, final body weight and albumin quality. Significant genotypeXdietary protein level interactions were observed for egg weight, albumin quality and feed consumption. The significance of these findings is discussed.
1579
P R O T E I N INTERACTIONS
TABLE 2.—Ntiltient composition of diets Control Diet Mean Crude protein (%) 17.0 Ether extract (%) 3.7 Crude fibre (%) 3.2 Calcium (%) 2.9 Phosphorus (%) 0.70 Metaboliable energy (kcal./ kg.)> 2890 1
Ingredient
(Control Diet
Low Protein Diet
%
%
Corn 36 35.25 Wheat 2.75 Stabilized tallow Soybean meal (50% protein) 15.5 Dehydrated alfalfa meal 2 6.25 Ground limestone 1.5 Dicalcium phosphate 0.25 Iodized salt 1 0.5 Micro-nutrients
40.8 40.05 1.55 7 2 6.25 1.6 0.25 0.5
1 Micro-nutrients added per kg. of feed Vitamin A (i.u.) 6300 Menadione Na biVitamin D 3 (i.c.u.) 1040 sulphite (mg.) 1.1 Vitamin B !2 (Mg.) 44 DL-methionine Choline Chloride (mg.) 500 (mg.) 125 Manganese (mg.) 30 Riboflavin (mg.) 3.3 Zinc (mg.) 30
Range
Mean
Range
15.2-19.1 2.9-4.2 2.4-3.8 2.3-3.4 0.6-0.7
14.5 3.4 3.1 2.7 0.65
13.2-15.3 2.4-4.2 2.4-3.9 2.0-3.2 0.6-0.8
2890
Calculated values.
egg production, feed consumption a n d body weight records were maintained on a pen basis. Two days eggs per pen per week were mass weighed and graded for size and quality according to official Canadian standards. Once every 28 days, 25 eggs per pen were taken for determination of specific gravity, albumin height and Haugh unit score. All performance traits were subjected to analysis of variance, following the model shown in Table 3, in which diets were considered a fixed effect, and genotypes as random. Cochran's approximate method was used to calculate F ratios for testing diets (Cochran and Cox,, 1957). RESULTS AND DISCUSSION
Throughout the 350-day test period, TABLE 1.—Composition of diets
Low Protein Diet
Nutrient
Diets. T h e split plot design used in this experiment provided a high degree of sensitivity for testing t h e significance of strain X diet interactions and strain differences, which were the points of major concern. T h e design was also chosen because it suited the laying house facility, and it simplified operations to feed a SUITABLE 3.—Analysis of variance
Diets (D) Between quadrants treated alike (Q) Genotypes (G) GenotypesXDiets
Error
1 o-Q2-|-o-GD2-|-17
16 O-E2+2<;O2 16 O-E2+O-GD2
32 O-E2
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
ing a n d management regime. A t 21 weeks of age they were transferred as pen units to the laying quarters. Each strain was represented b y a pen of birds located at random within each quadrant of t h e laying house. Pen size was 4 X 5 . 5 meters, a n d t h e number of birds per pen ranged from 57 to 69. The two diets (Table 1) were fed in diagonally opposite quadrants, which provided two pens per strain on each diet. T h e control diet h a d been tested a n d found adequate over two previous years {Aitken et al., 1969), whereas the second diet was formulated to be marginal in protein content, in t h e expectation t h a t it would reveal differences between genotypes without unduly depressing mean performance levels. Both diets h a d t h e same calculated metabolizable energy value of 2890 kcal./kg. T h e feeds were custom mixed b y a commercial company, which made deliveries at approximately 3 week intervals. Each mix was sampled and chemically analyzed for crude protein, ether extract, crude fibre, calcium and phosphorus (Table 2).
1580
AlTKEN, BlELY, NlKOLAICZUK, R.OBBLEE, SUMMERS AND BARR TABLE 4.—Performance over 350 days as influenced by diet Low Protein Diet
Control Diet
Trait
12.5 2189
13.2 2128
Egg production Per hen housed (No.) Per hen day X 100
219.6 67.2
211.3 64.9
116.S 2090 2.93
115.3 2141 •3.03
Feed consumption Per bird day (g.) Per dozen eggs (g.) Per unit weight of eggs Egg size and quality Mean egg weight (g.) Large+extra large eggs (%) Specific gravity Albumin height (mm.) Haugh unit score Grade B eggs (%)
59.5 65.9 1.082 5.66 72.6 3.6
58.9 61.4 1.082 5.54 71.8 4.2
gle diet in each quadrant. One disadvantage was the large whole plot error variance associated with diets, so that differences between diets were not statistically significant. However, the diet compariT A B L E ; 5.—Laying
Stocks. The stocks spanned as'" wide a range in level of production and body size as one would expect to encounter among commercial strains. Therefore, it is not surprising that statistical analysis revealed highly significant (P<0.01) differences among stocks in all performance traits. Four of the more important mea-
house performance (4 traits) presented by strain and diet Low ]protein diet. Relative values.1
Control diet. Absolute values Strain No.
Feed per Egg production bird day g%
Egg weight g-
Final body weight kg-
Feed per Egg production bird day
Egg weight
Final body weight
5 13 15 7 16 14 6 4 2 1 3 17 8 10 11 9 12
74.5 73.7 73.7 72.3 70.7 70.5 68.3 67.3 66.8 64.8 64.6 64.6 63.9 62.9 62.4 61.9 59.3
123.1 113.1 123.1 111.6 127.4 117.8 115.2 111.5 110.5 112.5 125.3 114.0 110.4 112.1 109.8 111.5 130.9
62.3 59.0 60.0 59.9 60.3 62.3 58.6 58.8 58.4 58.3 58.7 59.0 59.3 58.8 58.9 57.7 61.3
2.29 2.00 2.00 1.95 2.45 1.84 2.11 1.97 1.90 2.11 2.81 2.02 2.11 2.29 2.22 2.27 2.84
92.9 92.5 97.4 96.3 93.6 90.5 96.8 97.8 95.8 105.2* 100.9* 94.7 99.1 96.5 99.5 100.0* 95.4
102.3 93.7 94.7* 99.7 96.9 98.3 98.9 101.5 92.3* 98.5* 98.0* 97.8 100.6 104.5 103.7 104.0 98.0
99.2 93.6 97.8 98.7 98.9 100.0* 101.3* 99.6 94.0 98.4 102.2* 99.6 99.0 100.5* 99.8 101.1* 98.2
96.0 93.2 100.0* 97.7 96.3 95.1 97.8 97.7 90.5 97.8 96.8 102.3* 100.0* 98.0 97.8 98.0 98.4
Combined
67.2
116.5
59.5
2.18
96.6
98.9
98.9
97.9
1
Value for low protein dietX 100/corresponding value for control diet. * Cases where the birds did not respond in the expected manner to the low protein diet.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 27, 2015
Mortality (%) Final body weight (g.)
sons shown in Tables 4 and 5 suggest that there were probably true differences between the diets in a number of performance traits, had the test been designed to reveal them. Egg production, egg weight, final body weight and feed consumption were all lower on the marginal protein diet over all strains combined (Table 4), and were also lower for the majority of the strains when these were compared individually (Table 5). Traits which did not appear to be influenced by the diet were percent mortality and specific gravity of the eggs, but albumin quality was slightly superior on the control diet.
P R O T E I N INTERACTIONS
sures of performance are shown according to strain and diet in Table 5. To facilitate comparisons, the figures have been presented in absolute terms for the control diet, and in relative terms (low protein dietXIOO/control diet) for the low protein diet.
To illustrate this point, the manner in which the individual strains responded to the low protein diet is shown in some detail in Table 5. K r a u t m a n n (1969) points out t h a t a number of response mechanisms can come into play when laying hens are fed a diet which is marginal to requirements in protein content. The birds can reduce rate of egg production, or egg size, or body weight gains, or they can increase feed consumption beyond caloric require-
ments in an a t t e m p t to obtain more protein. Some or all of these mechanisms can be used in varying degrees in a manner characteristic of the particular strain. I n the present case, 3 of the strains did not respond to the low protein diet with the expected reduction in egg production, 5 did not reduce egg size, and 3 did not decrease body weight. At first glance, it might appear t h a t only 6 of the 17 strains increased feed consumption on the low protein diet, b u t in 7 of the remaining strains the drop in feed consumption was less than the corresponding drop in egg production. Hence only 4 strains deviated from the expected response and actually decreased feed consumption in relation to rate of egg production. T h e general conclusion from this study is t h a t genotype X dietary protein level interactions among egg production stocks tend to be the exception rather than the rule, b u t two factors come to mind which might explain discrepancies in the results of different investigators. The first concerns the type of diets used. Where a diet adequate in protein is compared with one which is severely deficient, one might expect strain differences to be magnified as compared with a case in which the adequate diet is compared with one which is marginal or only slightly deficient in protein. The second factor concerns the number of strains under test. If it happens t h a t most strains are similar in their protein requirements, the influence of an exceptional strain will be more apparent when it forms p a r t of a small population of strains than when it is p a r t of a large one. REFERENCES Aitken, J. R., J. Biely, N. Nikolaiczuk, A. R. Robblee and S. J. SHnger, 1969. Comparison of laying rations with and without animal protein at the Canadian random sample egg production test. Brit. Poultry Sci. 10: 247-253. Cochran, W. G., and G. M. Cox, 1957. Experimental
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Interactions. The only genotype X diet interactions which proved to be statistically significant were for egg weight and albumin quality ( P < 0 . 0 1 ) and for feed consumption ( P < 0 . 0 5 ) . In the other performance traits, notably egg production, most of the strains in the population under study appear to have responded in approximately the same manner to a diet marginal in protein content. However, this does not permit us to conclude t h a t in egg production, for example, there were no strains in the population which differed significantly in their response to the low protein diet. Where the number of strains under test is relatively large, and where the majority behave in approximately the same manner, the presence of a few strains which deviate considerably from the norm can be masked. Tests of the present type are more appropriate for estimating the importance of genotype X dietary protein level interactions in the population of strains considered as a whole, than for detecting the presence of individual strains which respond differently from one another.
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AlTKEN, BlELY, NlKOLAICZUK, ROBBLEE, SUMMERS AND BARR Krautmann, B. A., 1969. Strain interactions to marginal protein and amino acid diets. Poultry Sci. 48: 1831-1832. Marks, H. L., N. R. Gyles, H. R. Wilson, L. D. Tindell, W. A. Johnson, L. J. Dreesen, W. L. Blow, W. F. Krueger and P. B. Siegel, 1969. Genotype-environment interactions in egg production stocks of chickens. 2. Main effects and interactions of stock, protein, year and location. Poultry Sci. 48: 1070-1081. Moreng, R. E., H. L. Enos, W. A. Whittet and B. F. Miller, 1964. An analysis of strain response to dietary protein levels. Poultry Sci. 43: 630-638.
Safety and Toxicity of Oietary Organic Arsenicals Relative to Performance of Young Turkeys 3. NITARSONE 1 ' 2 T. W. SULLIVAN AND ALI A. AI.-TIMIMI Department of Poultry Science, University of Nebraska, Lincoln, Nebraska 68503 (Received for publication January 13, 1972) ABSTRACT Two experiments were conducted with Large White turkeys from day-old to 28 days of age. Nitarsone (4-nitrophenylarsonic acid) levels from 0.01 to 0.08 percent were fed in a ground yellow corn-soybean meal, basal diet containing 28% protein. Body weight of individual birds and the feed consumption of each experimental group were recorded at the end of 14 and 28 days. Birds were closely observed daily for toxicity symptoms and mortality. Percent tibia ash was determined at 28 days in the first experiment. The maximum safe dietary level of nitarsone relative to performance of young turkeys to 28 days of age was 0.02 percent in both experiments. Body weight gain to 28 days was significantly decreased (P<0.01) in poults fed 0.03 percent of the drug. Mortality was 11.1, 55.6, 54.2 and 100%, respectively, among poults fed 0.04, 0.05, 0.06 and 0.08 percent of nitarsone. Therefore, the dietary drug level necessary to cause 50 percent mortality in turkeys to 28 days (L.D. 50/28) was about 0.05 percent. Symptoms of nitarsone toxicity appeared during the second week and included: leg weakness, a tendency to sit, head tremors with eyes closed, some paralysis and loss of appetite. Percent tibia ash was significantly (P<0.05) increased when nitarsone (0.02, 0.04, or 0.06 percent) was present in the diet. POULTRY SCIENCE 5 1 : 1582-1586,
INTRODUCTION
N
ITARSONE or 4-nitrophenylarsonic acid is an organic arsenical compound used in poultry diets as an aid in prevention of infectious enterohepatitis or histomoniasis (blackhead disease). The approved level for this usage was formerly 0.025 percent but is presently 1 Published as Paper Number 3320, Journal series, Nebraska Agricultural Experiment Station. i2 From a thesis submitted by the junior author in partial fulfillment of the requirement for the Ph.D. degree.
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0.01875 percent of the diet (Feed Additive Compendium, 1971). Reports concerning the effect of nitarsone on body weight gain and feed efficiency are somewhat contradictory. McGuire and Morehouse (1952) reported 10.8 and 3.7 percent greater body weight gains in poults receiving 0.0066 and 0.05 percent of dietary nitarsone, respectively. Slinger et al. (1954), while studying the value of nitarsone (0.025%) for prevention of perosis in turkeys, observed a significant body weight depression. Sullivan
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Designs. Second Edition. John Wiley and Sons, New York. p. 467. Deaton, J. W., and J. H. Quisenberry, 1965. Effects of dietary protein level on performance of four commercial egg production stocks. Poultry Sci. 44: 936-942. Harms, R. H., and P. W. Waldroup, 1962. Strain differences in the protein requirement of laying hens. Poultry Sci. 41: 1985-1987. Harms, R. H., B. L. Damron and P. W. Waldroup, 1966. Influence of strain or breed upon the protein requirement of laying hens. Poultry Sci. 45: 272-275.