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Low Erucic Acid, Low Glucosinolate Rapeseed Meal, with and without Added Gums in the Layer Diet
Low Erucic Acid, Low Glucosinolate Rapeseed Meal, with and without Added Gums in the Layer Diet B. E. MARCH, D. B. BRAGG, and RAYMOND SOONG Department of Poultry Science, University of British Columbia, Vancouver, B. C, V6T 1WS Canada (Received for publication November 23,1977)
INTRODUCTION Rapeseed meal fed to laying birds has been variously reported to be without effect on mortality, to result in a slight increase in mortality, and to cause a high incidence of mortality (Jackson, 1969; Summers et al, 1969; Vogt et al, 1969; Clandinin and Robblee, 1970; Hall, 1972; March et al, 1972, 1975). Although numerous experiments have been conducted on the feeding of rapeseed meal to laying birds, the effect on mortality cannot be evaluated from many of them because the numbers of birds per treatment were insufficient or because the test period was inadequate. Both goitrogens and erucic acid have been suggested as responsible for increased mortality when rapeseed meal is fed (Vogt et al, 1969; March and Soong, 1976). The availability of meal manufactured from Brassica napus (cv Tower), which is low in both glucosinolates and erucic acid, made possible the following experiment. Gums from the refining of rapeseed oil may be utilized by adding them back to the meal. The possibility of adverse effects from this practice was also investigated with gums derived from both Tower oil and from Brassica napus (cv Midas) oil. Rapeseed gums are reported to be wellutilized by growing birds without adverse effect (Lall and Slinger, 1974; March, 1977).
MATERIALS AND METHODS The Tower meals used in the experiment 1978 Poultry Sci 57:1599-1604
contained 38 to 39% of crude protein. The meals with added gums from the refining of rapeseed oil contained 2% of gums derived from either Tower or Midas rapeseed oil. Metabolizable energy (ME) values of rapeseed meals wefe determined using 3-week-old chicks (March and Soong, 1978). The meal without gums contained 2280 kcal/kg dry weight, and the meals with Tower and Midas gums contained 2220 and 2390 kcal/kg, respectively. The Tower and Midas gums contained 11 and 234 ppm of sulphur, respectively. A control diet contained soybean meal as the protein supplement. The formulas of the experimental laying diets are shown in Table 1. The diets were calculated to contain 15.7% protein, 2.8% calcium, and 85% phosphorus. White Leghorn pullets of two strains (2056 Hyline and 2016 Babcock) were used. The pullets were reared under similar management conditions until they were placed on experiment at 25 weeks of age. The birds were vaccinated against Marek's disease, Newcastle disease, and infectious bronchitis and had received a coccidiostat during the growing period. Each diet was fed to 514 Hyline pullets and 504 Babcock pullets. The pullets were housed in floor pens, community cages, and individual cages. Equal numbers of birds of each strain were placed on each treatment in each environment with the exception of the individual cages. In the individual cages 169 Hyline and 159 Babcock pullets were given each diet. All the birds which died from the entire
1599
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ABSTRACT White Leghorn pullets of two strains were fed 20% of Tower rapeseed meal in the laying diet for one year. The rapeseed meal was manufactured with and without addition of 2% of either Tower or Midas gums. Control birds were fed a soybean meal diet. Each diet was fed to 1018 birds of two commercial lines. Rate of production during a one-year period was similar on all diets. Gums were without effect on any aspect of production. Overall mortality in the experiment was 11.7%, or 6.5% when neoplasms were excluded. There was a strain difference in the rate of mortality which was not due to any single cause. The birds fed the rapeseed meal with Midas gums had the highest mortality. The incidence of haemorrhagic lesions in various tissues was significantly affected by diet, being lowest in the birds fed the soybean meal diet and highest in the birds fed the rapeseed meal with added Midas gums.
1600
MARCH ET AL. TABLE 1.—Composition of laying diets
Ingredient
Diet 1
15.0
Diet 3
Diet 4
. •.
...
...
20.0 20.0 30.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.6 2750
25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.8 2615
25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.8 2605
20.0 25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.5 2630
Rapeseed meal derived from Tower seed. Per kg of diet: manganese sulphate, 170 mg; zinc sulphate, 100 mg; riboflavin, 3.8 mg; calcium pantothenate, 10 mg; niacin, 10 mg; vitamin 1$! 2 , 3 meg; vitamin A, 6600 IU; vitamin D 3 , 660 ICU.
population of 4072 birds were subjected to post mortem examination. Egg production was recorded by 28-day periods and egg size was measured at 28-day intervals from 1200 pullets housed in floor pens, 1312 pullets in individual cages and 700 pullets in community cages. A record of feed consumption was kept for the 1200 pullets in floor pens and the 700 pullets in community cages. At the conclusion of the experiment, 12 birds from each of the experimental treatments in the community cages were killed, and thyroid glands were removed and weighed. All birds in the experiment were weighed at the beginning and end of the test. The experiment was concluded after 364 days. RESULTS The data regarding body weights, egg production, and feed efficiency are summarized in Table 2. The final body weights of the birds of the two strains were similar. Birds of both strains were lighter when fed the rapeseed meal diets than when fed the control soybean meal diet, and there was no significant interaction between strain and diet. The rate of egg production, however, was significantly higher by the Babcock than by the Hyline birds but was not significantly affected by the diet that was fed. There was no significant interaction between strain and diet. The type of housing significantly affected production rate. Highest production was attained in the floor pens and
lowest in the community cages. There were no significant interactions, however, among the type of housing, strain, and diet in the effects on egg production. Average egg weight was heavier from the birds fed soybean meal than from those fed the rapeseed meal. Efficiency of feed conversion, calculated on the basis of egg mass produced, was poorer for the birds in the community cages than for those in the floor pens. Feed efficiency was somewhat poorer for the birds fed the rapeseed meals than for those fed soybean meal, but the effect was not significant at the 5% level of probability. Mortality data, summarized according to the principal causes, are shown in Table 3. Overall mortality was 11.7% of the total population housed. Mortality was higher in the Hyline (14.8%) than in the Babcock strain (8.4%). This strain difference was due to differences in the incidence of all categories of causes of death. Neoplasia, principally leukosis, was diagnosed as responsible for 5.2% mortality in the population or 44% of the total mortality. Infectious disease was not under consideration in this experiment. Mortality from neoplasia was accordingly separated out in Table 3. The residual mortality was essentiaiiy that due to metabolic disorders. Analysis by chi-square of the pooled mortality data from the two strains revealed that the total mortality in the birds fed the rapeseed meal with added Midas gums was considerably higher (P<.05) than in the birds fed
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
Soybean meal Rapeseed meala (no gums), 39.6% protein Rapeseed meal + Tower gums,, 39.3% protein Rapeseed meal + Midas gums, 37.8% protein Ground wheat Ground corn Ground oats Dehydrated cereal grass Calcium phosphate Limestone Iodized salt Micronutrientsb Calculated protein, % ME, kcal/kg
Diet 2
72.2C 63.1* 68.7b 69.8a 67.6 a 67.6 a 67.4a
1.64a 1.66a 1.63a
1.70b 1.63 a 1.62a 1.62a
Floor pens Community cages Individual cages
Diet Diet Diet Diet
72.7 59.7 ND
64.1 61.7 3.1
2.6
77.3 60.3
1.7
Diet
Overall averages*
63.5 59.1 ND
57.2 60.6 3.28
70.6 58.5 2.88
1.60
Diet 4
*Of differences among diet means.
a,b,c Items with a common superscript are not significantly different (P<.05). No interactions among strain, housing
1 2 3 4
65.9 a 70.2b
65.8 58.7 ND
1.64a 1.65a
64.8 58.8 ND
64.7 59.1 3.17
Hyline strain Babcock strain
69.3 60.2 ND
Individual cages Egg production, % Avg egg wt, g g/feed consumed/g egg produced
63.1 60.3 3.09
68.5 58.3 2.95
1.61
Body wt
66.4 60.9 2.96
Community cages Egg production, % Avg egg wt, g g feed consumed/g egg produced
68.2 59.3 2.96
1.64
Diet 3
Hyline strain Diet 2
Egg production
68.7 59.2 2.84
1.69
Floor pens Egg production, % hen-day basis Avg egg wt, g g feed consumed/g egg produced
Final body wt, kg
Diet 1
TABLE 2.—Summary of production data from birds fed laying diets containing the following res 1) soybean meal, 2) Tower rapeseed meal without added gums, 3) Tower rapeseed meal w 4) Tower rapeseed meal with Midas gums
.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
1
No. of birds placed on experiment Total mortality Other than neoplasms Liver and kidney disorders Haemorrhagic lesions
1018 112 59 13 6
33 6
Mortality other than that caused by neoplasms Haemorrhagic lesions
Diet
40 9 9 15 73
514
Diagnosis of cause of mortality Neoplasms Liver and kidney disorders Reproductive disorders Miscellaneous Total
No. of birds placed on experiment
Diet
55 14
40 11
27 8
3 1018 111 67 27 13
2 1018 108 58 28 13
Mortality in both strains
42 15 12 28 97
514
29 17 9 14 69
514
39 16 4 7 66
514
Hyline strain
TABLE 3.—Summary of mortality in birds fed laying diets containing the following respecti 1) soybean meal, 2) Tower rapeseed meal without added gums, 3) Tower rapeseed meal w 4) Tower rapeseed meal with Midas gums
s.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
GUMS IN LAYER DIET
DISCUSSION Rapeseed meal at a 20% dietary level was substituted for all of the soybean meal and for a portion of the wheat in the control diet. The calculated ME values of the rapeseed meal diets were approximately 100 kcal/kg below the ME value of the soybean meal control diet. The lower dietary ME of the rapeseed meal diets may account for the reduction in egg size and the slightly poorer feed conversion obtained with these diets. The degree of thyroidal enlargement from Tower meal in this experiment was much lower than that observed previously in birds which had been fed rapeseed meal from other cultivars for an extended period (Leung and March, 1976). Tower meal has previously been observed to have some goitrogenicity when fed at
TABLE 4.—Effect
high levels to growing chicks (March and Soong, 1978). The rate of mortality was higher in the Hyline (14.8%) than in the Babcock (8.4%) birds. The difference was mainly due to the greater incidence of mortality from leukosis in the Hyline birds. The residual mortality from all other causes represented 7.5 and 5.5%, respectively, of the original populations of the Hyline and Babcock birds. The mortality data for the two strains were therefore pooled for analysis. Liver and kidney disorders were combined in the summary of mortality in Table 3 because they were frequently associated. Although there was more mortality involving liver and kidney dysfunction in the birds fed rapeseed meal, the incidence of mortality from this cause was not significantly different from that in the control birds fed soybean meal. Haemorrhagic lesions, which occurred in some cases in conjunction with liver and kidney disorders as well as in other tissues, were significantly (P<.05) more frequent in the birds receiving rapeseed meal. Highest mortality involving haemorrhage occurred in the birds fed the rapeseed meal with added Midas gums. However, the Midas gums had no effect on egg production, egg weight, or feed conversion. Rapeseed meal and rapeseed oil have been implicated in a haemorrhagic fatty liver syndrome (Jackson, 1969; Vogt et al, 1969; Clandinin and Robblee, 1970; Hall, 1972; and March et al., 1972, 1975). Increased mortality does not, however, always result when rapeseed products are fed to laying birds. One reason is the genetic difference in susceptibility which was noted by Jackson (1969), Hall
on thyroid weights3- of feeding 20% of Tower rapeseed meal in the diet for 50 weeks Hyline strain thyroid weight 0
Dietary protein supplement Soybean meal Tower meal (no gums) Tower meal + Tower gums Tower meal + Midas gums
Babcock strain thyroid weight^t
(mg)
(mg/ 100 g BW)
(mg)
(mg/ 100 g BW)
132.8 299.7 285.1 296.3
7.1 17.1 16.3 17.9
128.4 263.1 236.5 305.2
7.3 15.7 13.7 17.8
Analysis of variance of thyroid weights (mg/100 g BW). Source of variation; diet, significant at 5% level; strain; not significant; and diet X strain interaction, not significant. Average of 12 birds per treatment.
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the other diets. Incidence of liver and kidney disorders was similar with the three rapeseed meal diets and higher than with the soybean meal control diet, but the effect was not significant at the 5% level. Haemorrhagic lesions showed significant (P<.05) differences in frequency among the dietary treatments. They were more commonly observed in the birds fed the rapeseed meal diets than in the soybeanmeal fed birds and had their highest incidence in the birds fed the rapeseed meal with added Midas gums. The thyroid weights, determined when the birds had been almost a year on the experiment, are given in Table 4. Birds of both strains showed thyroidal enlargement when they had been fed the rapeseed meal diets.
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1604
MARCH ET AL.
ACKNOWLEDGMENTS The study was supported by the Rapeseed Association of Canada under the Rapeseed Utilization Assistance Programme, Canada Department of Trade Industry and Commerce. The authors thank F. W. Hougen, Department of Plant Science, University of Manitoba, Winnipeg, Manitoba for the sulphur analyses of the rapeseed gums. REFERENCES Qandinin, D. R., and A. R. Robblee, 1970. Canadian experience with the use of rapeseed meal in rations for poultry. Page 267-273 in Proc. Int. Conf. Science, Technol. and Marketing of Rapeseed and Rapeseed Products. Dept. of Industry, Trade and Commerce, Ottawa, Canada. Donaldson, W. E., and C. D. Gordon, 1960. The effect of 3% added animal fat on laying hen performance. Poultry Sci. 39:582-587. Hall, S. A., 1972. Lysis of hepaticreticulin: An unusual lesion in laying fowls probably associated
with rapeseed meal. Vet. Rec. 91:495. Jackson, N., 1969. Toxicity of rapeseed meal and its use as a protein supplement in the diet of two hybrid strains of caged laying birds. J. Sci. Food Agr. 20:734-740. Lall, S. P., and S. J. Slinger, 1974. Effect of refining on the nutritional value of rapeseed oils for the chick and rat. J. Sci. Food Agr. 25:423-432. Leung, P., and B. E. March, 1976. The thyroidal response to chronic goitrogenic stimulation and the persistence of effects of early goitrogenic stimulation. Can. J. Physiol. Pharmacol. 54:583-589. March, B. E., 1977. Response of chicks to the feeding of different rapeseed oils and rapeseed oil fractions. Can. J. Anim. Sci. 57:137-140. March, B. E., and J. Biely, 1962. The effect of dietary fat level on the rate of mortality in caged layers. Poultry Sci. 41:9-12. March, B. E., and J. Biely, 1963. The effects of dietary fat and energy levels on the performance of caged laying birds. Poultry Sci. 42:20—24. March, B. E., J. Biely, and R. Soong, 1972. Rapeseed meal in the chicken breeder diet. Effects on production, mortality, hatchability and progeny. Poultry Sci. 51:1589-1596. March, B. E., J. Biely, and R. Soong, 1975. The effects of rapeseed meal fed during the growing and/or laying periods on mortality and egg production in chickens. Poultry Sci. 54:1875-1882. March, B. E., and R. Soong, 1976. Mortality and production characteristics of laying chickens fed highand Iow-erucic acid rapeseed oils. Poultry Sci. 55:1557-1560. March, B. E., and R. Soong, 1978. Effects of added rapeseed gums in chick diets containing soybean meal or low crude acid, low glucosinolate rapeseed meal. Can. J. Anim. Sci. 58:111-113. Summers, J. D., H. S. Bayley, W. F. Peffer, and S. J. Slinger, 1969. The value of rapeseed meal for growing pullets and laying hens. Can. J. Anim. Sci. 49:97-103. Vogt, Von H., H. J. Schubert, K. Stute, and W. R. Rauch, 1969. Feeding value and use of rapeseed meal in feeding poultry. 3. Rapeseed meal for laying hens. Arch. Geflugelk, 33:119-124. Weiss, H. S., and H. Fisher, 1957. Plasma lipid and organ changes associated with the feeding of animal fat to laying chickens. J. Nutr. 61:267—280.
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(1972), and March et al. (1975). It must also be noted that the liver lesions are not unique to birds fed rapeseed meal or rapeseed oil. When liver lesions have been observed in birds fed rapeseed meal under experimental conditions, control birds fed diets containing no rapeseed meal have also shown a certain, although lower, incidence of the condition. Likewise, when both animal and vegetable fats and oils were first investigated as supplements in laying diets, increased mortality with observations of liver derangement were reported in birds fed the supplements (Weiss and Fisher, 1957; Donaldson and Gordon, I960; March and Biely, 1962, 1963). The fact that haemorrhagic lesions occurred in other than liver tissue in the present experiment suggests the presence of an agent affecting the integrity of the vascular system.
INTRODUCTION Rapeseed meal fed to laying birds has been variously reported to be without effect on mortality, to result in a slight increase in mortality, and to cause a high incidence of mortality (Jackson, 1969; Summers et al, 1969; Vogt et al, 1969; Clandinin and Robblee, 1970; Hall, 1972; March et al, 1972, 1975). Although numerous experiments have been conducted on the feeding of rapeseed meal to laying birds, the effect on mortality cannot be evaluated from many of them because the numbers of birds per treatment were insufficient or because the test period was inadequate. Both goitrogens and erucic acid have been suggested as responsible for increased mortality when rapeseed meal is fed (Vogt et al, 1969; March and Soong, 1976). The availability of meal manufactured from Brassica napus (cv Tower), which is low in both glucosinolates and erucic acid, made possible the following experiment. Gums from the refining of rapeseed oil may be utilized by adding them back to the meal. The possibility of adverse effects from this practice was also investigated with gums derived from both Tower oil and from Brassica napus (cv Midas) oil. Rapeseed gums are reported to be wellutilized by growing birds without adverse effect (Lall and Slinger, 1974; March, 1977).
MATERIALS AND METHODS The Tower meals used in the experiment 1978 Poultry Sci 57:1599-1604
contained 38 to 39% of crude protein. The meals with added gums from the refining of rapeseed oil contained 2% of gums derived from either Tower or Midas rapeseed oil. Metabolizable energy (ME) values of rapeseed meals wefe determined using 3-week-old chicks (March and Soong, 1978). The meal without gums contained 2280 kcal/kg dry weight, and the meals with Tower and Midas gums contained 2220 and 2390 kcal/kg, respectively. The Tower and Midas gums contained 11 and 234 ppm of sulphur, respectively. A control diet contained soybean meal as the protein supplement. The formulas of the experimental laying diets are shown in Table 1. The diets were calculated to contain 15.7% protein, 2.8% calcium, and 85% phosphorus. White Leghorn pullets of two strains (2056 Hyline and 2016 Babcock) were used. The pullets were reared under similar management conditions until they were placed on experiment at 25 weeks of age. The birds were vaccinated against Marek's disease, Newcastle disease, and infectious bronchitis and had received a coccidiostat during the growing period. Each diet was fed to 514 Hyline pullets and 504 Babcock pullets. The pullets were housed in floor pens, community cages, and individual cages. Equal numbers of birds of each strain were placed on each treatment in each environment with the exception of the individual cages. In the individual cages 169 Hyline and 159 Babcock pullets were given each diet. All the birds which died from the entire
1599
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
ABSTRACT White Leghorn pullets of two strains were fed 20% of Tower rapeseed meal in the laying diet for one year. The rapeseed meal was manufactured with and without addition of 2% of either Tower or Midas gums. Control birds were fed a soybean meal diet. Each diet was fed to 1018 birds of two commercial lines. Rate of production during a one-year period was similar on all diets. Gums were without effect on any aspect of production. Overall mortality in the experiment was 11.7%, or 6.5% when neoplasms were excluded. There was a strain difference in the rate of mortality which was not due to any single cause. The birds fed the rapeseed meal with Midas gums had the highest mortality. The incidence of haemorrhagic lesions in various tissues was significantly affected by diet, being lowest in the birds fed the soybean meal diet and highest in the birds fed the rapeseed meal with added Midas gums.
1600
MARCH ET AL. TABLE 1.—Composition of laying diets
Ingredient
Diet 1
15.0
Diet 3
Diet 4
. •.
...
...
20.0 20.0 30.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.6 2750
25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.8 2615
25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.8 2605
20.0 25.0 29.5 15.0 2.5 2.5 5.0 .35 .15 15.5 2630
Rapeseed meal derived from Tower seed. Per kg of diet: manganese sulphate, 170 mg; zinc sulphate, 100 mg; riboflavin, 3.8 mg; calcium pantothenate, 10 mg; niacin, 10 mg; vitamin 1$! 2 , 3 meg; vitamin A, 6600 IU; vitamin D 3 , 660 ICU.
population of 4072 birds were subjected to post mortem examination. Egg production was recorded by 28-day periods and egg size was measured at 28-day intervals from 1200 pullets housed in floor pens, 1312 pullets in individual cages and 700 pullets in community cages. A record of feed consumption was kept for the 1200 pullets in floor pens and the 700 pullets in community cages. At the conclusion of the experiment, 12 birds from each of the experimental treatments in the community cages were killed, and thyroid glands were removed and weighed. All birds in the experiment were weighed at the beginning and end of the test. The experiment was concluded after 364 days. RESULTS The data regarding body weights, egg production, and feed efficiency are summarized in Table 2. The final body weights of the birds of the two strains were similar. Birds of both strains were lighter when fed the rapeseed meal diets than when fed the control soybean meal diet, and there was no significant interaction between strain and diet. The rate of egg production, however, was significantly higher by the Babcock than by the Hyline birds but was not significantly affected by the diet that was fed. There was no significant interaction between strain and diet. The type of housing significantly affected production rate. Highest production was attained in the floor pens and
lowest in the community cages. There were no significant interactions, however, among the type of housing, strain, and diet in the effects on egg production. Average egg weight was heavier from the birds fed soybean meal than from those fed the rapeseed meal. Efficiency of feed conversion, calculated on the basis of egg mass produced, was poorer for the birds in the community cages than for those in the floor pens. Feed efficiency was somewhat poorer for the birds fed the rapeseed meals than for those fed soybean meal, but the effect was not significant at the 5% level of probability. Mortality data, summarized according to the principal causes, are shown in Table 3. Overall mortality was 11.7% of the total population housed. Mortality was higher in the Hyline (14.8%) than in the Babcock strain (8.4%). This strain difference was due to differences in the incidence of all categories of causes of death. Neoplasia, principally leukosis, was diagnosed as responsible for 5.2% mortality in the population or 44% of the total mortality. Infectious disease was not under consideration in this experiment. Mortality from neoplasia was accordingly separated out in Table 3. The residual mortality was essentiaiiy that due to metabolic disorders. Analysis by chi-square of the pooled mortality data from the two strains revealed that the total mortality in the birds fed the rapeseed meal with added Midas gums was considerably higher (P<.05) than in the birds fed
Downloaded from http://ps.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
Soybean meal Rapeseed meala (no gums), 39.6% protein Rapeseed meal + Tower gums,, 39.3% protein Rapeseed meal + Midas gums, 37.8% protein Ground wheat Ground corn Ground oats Dehydrated cereal grass Calcium phosphate Limestone Iodized salt Micronutrientsb Calculated protein, % ME, kcal/kg
Diet 2
72.2C 63.1* 68.7b 69.8a 67.6 a 67.6 a 67.4a
1.64a 1.66a 1.63a
1.70b 1.63 a 1.62a 1.62a
Floor pens Community cages Individual cages
Diet Diet Diet Diet
72.7 59.7 ND
64.1 61.7 3.1
2.6
77.3 60.3
1.7
Diet
Overall averages*
63.5 59.1 ND
57.2 60.6 3.28
70.6 58.5 2.88
1.60
Diet 4
*Of differences among diet means.
a,b,c Items with a common superscript are not significantly different (P<.05). No interactions among strain, housing
1 2 3 4
65.9 a 70.2b
65.8 58.7 ND
1.64a 1.65a
64.8 58.8 ND
64.7 59.1 3.17
Hyline strain Babcock strain
69.3 60.2 ND
Individual cages Egg production, % Avg egg wt, g g/feed consumed/g egg produced
63.1 60.3 3.09
68.5 58.3 2.95
1.61
Body wt
66.4 60.9 2.96
Community cages Egg production, % Avg egg wt, g g feed consumed/g egg produced
68.2 59.3 2.96
1.64
Diet 3
Hyline strain Diet 2
Egg production
68.7 59.2 2.84
1.69
Floor pens Egg production, % hen-day basis Avg egg wt, g g feed consumed/g egg produced
Final body wt, kg
Diet 1
TABLE 2.—Summary of production data from birds fed laying diets containing the following res 1) soybean meal, 2) Tower rapeseed meal without added gums, 3) Tower rapeseed meal w 4) Tower rapeseed meal with Midas gums
.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
1
No. of birds placed on experiment Total mortality Other than neoplasms Liver and kidney disorders Haemorrhagic lesions
1018 112 59 13 6
33 6
Mortality other than that caused by neoplasms Haemorrhagic lesions
Diet
40 9 9 15 73
514
Diagnosis of cause of mortality Neoplasms Liver and kidney disorders Reproductive disorders Miscellaneous Total
No. of birds placed on experiment
Diet
55 14
40 11
27 8
3 1018 111 67 27 13
2 1018 108 58 28 13
Mortality in both strains
42 15 12 28 97
514
29 17 9 14 69
514
39 16 4 7 66
514
Hyline strain
TABLE 3.—Summary of mortality in birds fed laying diets containing the following respecti 1) soybean meal, 2) Tower rapeseed meal without added gums, 3) Tower rapeseed meal w 4) Tower rapeseed meal with Midas gums
s.oxfordjournals.org/ at National Institute of Education Library, Serials Unit on June 9, 2015
GUMS IN LAYER DIET
DISCUSSION Rapeseed meal at a 20% dietary level was substituted for all of the soybean meal and for a portion of the wheat in the control diet. The calculated ME values of the rapeseed meal diets were approximately 100 kcal/kg below the ME value of the soybean meal control diet. The lower dietary ME of the rapeseed meal diets may account for the reduction in egg size and the slightly poorer feed conversion obtained with these diets. The degree of thyroidal enlargement from Tower meal in this experiment was much lower than that observed previously in birds which had been fed rapeseed meal from other cultivars for an extended period (Leung and March, 1976). Tower meal has previously been observed to have some goitrogenicity when fed at
TABLE 4.—Effect
high levels to growing chicks (March and Soong, 1978). The rate of mortality was higher in the Hyline (14.8%) than in the Babcock (8.4%) birds. The difference was mainly due to the greater incidence of mortality from leukosis in the Hyline birds. The residual mortality from all other causes represented 7.5 and 5.5%, respectively, of the original populations of the Hyline and Babcock birds. The mortality data for the two strains were therefore pooled for analysis. Liver and kidney disorders were combined in the summary of mortality in Table 3 because they were frequently associated. Although there was more mortality involving liver and kidney dysfunction in the birds fed rapeseed meal, the incidence of mortality from this cause was not significantly different from that in the control birds fed soybean meal. Haemorrhagic lesions, which occurred in some cases in conjunction with liver and kidney disorders as well as in other tissues, were significantly (P<.05) more frequent in the birds receiving rapeseed meal. Highest mortality involving haemorrhage occurred in the birds fed the rapeseed meal with added Midas gums. However, the Midas gums had no effect on egg production, egg weight, or feed conversion. Rapeseed meal and rapeseed oil have been implicated in a haemorrhagic fatty liver syndrome (Jackson, 1969; Vogt et al, 1969; Clandinin and Robblee, 1970; Hall, 1972; and March et al., 1972, 1975). Increased mortality does not, however, always result when rapeseed products are fed to laying birds. One reason is the genetic difference in susceptibility which was noted by Jackson (1969), Hall
on thyroid weights3- of feeding 20% of Tower rapeseed meal in the diet for 50 weeks Hyline strain thyroid weight 0
Dietary protein supplement Soybean meal Tower meal (no gums) Tower meal + Tower gums Tower meal + Midas gums
Babcock strain thyroid weight^t
(mg)
(mg/ 100 g BW)
(mg)
(mg/ 100 g BW)
132.8 299.7 285.1 296.3
7.1 17.1 16.3 17.9
128.4 263.1 236.5 305.2
7.3 15.7 13.7 17.8
Analysis of variance of thyroid weights (mg/100 g BW). Source of variation; diet, significant at 5% level; strain; not significant; and diet X strain interaction, not significant. Average of 12 birds per treatment.
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the other diets. Incidence of liver and kidney disorders was similar with the three rapeseed meal diets and higher than with the soybean meal control diet, but the effect was not significant at the 5% level. Haemorrhagic lesions showed significant (P<.05) differences in frequency among the dietary treatments. They were more commonly observed in the birds fed the rapeseed meal diets than in the soybeanmeal fed birds and had their highest incidence in the birds fed the rapeseed meal with added Midas gums. The thyroid weights, determined when the birds had been almost a year on the experiment, are given in Table 4. Birds of both strains showed thyroidal enlargement when they had been fed the rapeseed meal diets.
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ACKNOWLEDGMENTS The study was supported by the Rapeseed Association of Canada under the Rapeseed Utilization Assistance Programme, Canada Department of Trade Industry and Commerce. The authors thank F. W. Hougen, Department of Plant Science, University of Manitoba, Winnipeg, Manitoba for the sulphur analyses of the rapeseed gums. REFERENCES Qandinin, D. R., and A. R. Robblee, 1970. Canadian experience with the use of rapeseed meal in rations for poultry. Page 267-273 in Proc. Int. Conf. Science, Technol. and Marketing of Rapeseed and Rapeseed Products. Dept. of Industry, Trade and Commerce, Ottawa, Canada. Donaldson, W. E., and C. D. Gordon, 1960. The effect of 3% added animal fat on laying hen performance. Poultry Sci. 39:582-587. Hall, S. A., 1972. Lysis of hepaticreticulin: An unusual lesion in laying fowls probably associated
with rapeseed meal. Vet. Rec. 91:495. Jackson, N., 1969. Toxicity of rapeseed meal and its use as a protein supplement in the diet of two hybrid strains of caged laying birds. J. Sci. Food Agr. 20:734-740. Lall, S. P., and S. J. Slinger, 1974. Effect of refining on the nutritional value of rapeseed oils for the chick and rat. J. Sci. Food Agr. 25:423-432. Leung, P., and B. E. March, 1976. The thyroidal response to chronic goitrogenic stimulation and the persistence of effects of early goitrogenic stimulation. Can. J. Physiol. Pharmacol. 54:583-589. March, B. E., 1977. Response of chicks to the feeding of different rapeseed oils and rapeseed oil fractions. Can. J. Anim. Sci. 57:137-140. March, B. E., and J. Biely, 1962. The effect of dietary fat level on the rate of mortality in caged layers. Poultry Sci. 41:9-12. March, B. E., and J. Biely, 1963. The effects of dietary fat and energy levels on the performance of caged laying birds. Poultry Sci. 42:20—24. March, B. E., J. Biely, and R. Soong, 1972. Rapeseed meal in the chicken breeder diet. Effects on production, mortality, hatchability and progeny. Poultry Sci. 51:1589-1596. March, B. E., J. Biely, and R. Soong, 1975. The effects of rapeseed meal fed during the growing and/or laying periods on mortality and egg production in chickens. Poultry Sci. 54:1875-1882. March, B. E., and R. Soong, 1976. Mortality and production characteristics of laying chickens fed highand Iow-erucic acid rapeseed oils. Poultry Sci. 55:1557-1560. March, B. E., and R. Soong, 1978. Effects of added rapeseed gums in chick diets containing soybean meal or low crude acid, low glucosinolate rapeseed meal. Can. J. Anim. Sci. 58:111-113. Summers, J. D., H. S. Bayley, W. F. Peffer, and S. J. Slinger, 1969. The value of rapeseed meal for growing pullets and laying hens. Can. J. Anim. Sci. 49:97-103. Vogt, Von H., H. J. Schubert, K. Stute, and W. R. Rauch, 1969. Feeding value and use of rapeseed meal in feeding poultry. 3. Rapeseed meal for laying hens. Arch. Geflugelk, 33:119-124. Weiss, H. S., and H. Fisher, 1957. Plasma lipid and organ changes associated with the feeding of animal fat to laying chickens. J. Nutr. 61:267—280.
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(1972), and March et al. (1975). It must also be noted that the liver lesions are not unique to birds fed rapeseed meal or rapeseed oil. When liver lesions have been observed in birds fed rapeseed meal under experimental conditions, control birds fed diets containing no rapeseed meal have also shown a certain, although lower, incidence of the condition. Likewise, when both animal and vegetable fats and oils were first investigated as supplements in laying diets, increased mortality with observations of liver derangement were reported in birds fed the supplements (Weiss and Fisher, 1957; Donaldson and Gordon, I960; March and Biely, 1962, 1963). The fact that haemorrhagic lesions occurred in other than liver tissue in the present experiment suggests the presence of an agent affecting the integrity of the vascular system.