- Email: [email protected]
Vitamin E Activity of Selenium in Turkey Hatchability
59
EFFECT OF KIDNEYS ON SHELF-LIFE TABLE 8.—Plate counts of inoculum from kidneys and livers Kidney
Liver
No. colonies per plate
No. plates
0 1 2 4 5 Discarded lab errors
8 6 1 1 1 2
% of total plates
No. colonies per plate
42 31 •S 5 5 10
No. plates
% of total plates
16 2 1
84.2 10.S 5.2
average weight increase from chilling 10week old fryers in ice slush for 4 hours was 4.02% for those with kidneys and 5.29% for those without kidneys which difference was significant at the 1% level of probability. Shelf-life was extended on the average SUMMARY by 1.27 days with fryers which had the Tests were conducted to determine the kidneys removed. Approximately 42% of the plates with average loss in warm eviscerated yields of 8-week old broilers, 10-week old fryers, and inoculum from kidneys and 84% of those one-year old S. C. White Leghorn fowl be- from livers showed no colonies. Part of the fore and after kidney removal. The percent plates with growth had only one colony, loss in yield from kidney removal was which appeared to be Bacillus mycoides. 0.82% for the 8-week old broilers, approxi- The largest number of bacterial colonies in mately 0.70% for each group of 10-week any of the plates did not exceed 5. Other old fryers, and 0.66% for the S. C. White tests need to be conducted under plant conLeghorn fowl. These differences were sig- ditions to further evaluate kidney removal nificant at the 1 % level of probability. The from poultry carcasses.
Vitamin E Activity of Selenium in Turkey Hatchability C. R. CEEGER, R. H. MITCHELL, R. L. ATKINSON, T. M FERGUSON, Departments
B. L. REID AND J. R. COUCH of Biochemistry and Nutrition and Poultry Science, Texas A & M College, College Station, Texas (Received for publication May 19, 1959)
INTRODUCTION
NUMBER of workers have reported the vitamin E-like activity of selenium in preventing exudative diathesis in chicks (Schwartz et al., 1957; Reid et al., 1958; and Patterson et al., 1957). Schwartz
A
et al. (1957) reported dried brewers yeast and vitamin-free casein completely prevented symptoms of exudative diathesis and promoted good growth when fed at the 10% level in the diet of rats. They also reported the presence of a factor 3, which
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
the results of contamination, it seems logical to assume that bacterially infected tissue would give more colonies per plate than the number observed. Of course, viruses could have been present in the agar without being noticeable.
60
CEEGER, MITCHELL, ATKINSON, FERGUSON, REID AND COUCH
ents has been found to decrease after 8 to 12 weeks of egg production if the diet is not fortified with vitamin E and unidentified factor sources (Atkinson et al., 1955; Ferguson et al., 1956; Feldman, 1957). The present experiment was designed to determine the effects of supplements of selenium, dried brewers yeast and d-alpha tocopheryl acetate on the reproductive performance of Beltsville Small White turkey hens maintained on wire floors. The supplements were added to the diet at the end of a nine-week laying period, during which time all groups were fed a diet which was low in vitamin E and contained no unidentified factor sources. METHODS One hundred-forty Beltsville Small White turkey hens were divided into 7 groups of 20 birds each and placed in 12 ft. X 15 ft. pens with raised wire floors. Twenty additional hens (group 1) were progeny of birds which had been maintained on wire, and fed vitamin E-low diets for 5 generations. The birds in groups 2 through 8 had been reared to maturity on the range of the Texas Agricultural Experiment Station poultry farm and had been fed a practical diet containing adequate amounts of known nutrients, antibiotics and sources of unidentified growth factors. All groups were fed a diet low in vitamin E for 9 weeks prior to the initiation of the experiment; groups 1 and 2 were maintained on this diet throughout the twelve-week experimental period. The composition of the basal diet was as follows: 25% soybean oil meal, 69% ground milo, 3 % defluorinated phosphate, 2.5% ground oyster shell, and 0.5% sodium chloride. The following were added per pound of feed: 9,000 I.U. vitamin A (stabilized), 1,200 I.C.U. vitamin D 3 , 1 mg. menadione sodium bisulfite, 20 mg. niacin, 2 mg. riboflavin, 12.5 mg. calcium pantho-
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
they described as, "The biologically active, selenium containing component, or components, present in nutrients and other materials of biological origin," to be present in dried brewers yeast. Creech et al. (1957) showed that exudative diathesis, produced in Beltsville Small White turkey poults, could be prevented by the addition of alpha-tocopherol acetate to the diet. Dried brewers yeast was also found to prevent this condition. These investigators determined the relationship between serum protein of the poult and the supplements to the diets of the dams. Results demonstrated that supplementation of the synthetic maternal diet with dried brewers yeast or alpha-tocopherol acetate significantly increased the A/G ratio over that of poults from dams on vitamin E low diets. Creech and co-workers also reported that the factor in dried brewers yeast was transmitted to a high degree from the dam through the egg to the poult, and was effective in preventing exudative diathesis. Atkinson et al. (1955) reported a 36% increase in hatchability when alpha-tocopherol acetate was added to a low vitamin E diet for Beltsville Small White turkey hens. An increase in hatchability was also obtained by Ferguson et al. (1956) when vitamin E was added as a supplement to the diet of Broad Breasted Bronze turkey hens. Jensen (1953) reported beneficial effects on hatchability of eggs from Empire White turkey hens when vitamin E was supplemented to the diet. Ferguson et al. (1954) reported certain abnormalities of the eye of Beltsville Small White turkey embryos obtained from eggs of hens fed a diet low in vitamin E. Supplementation of the all-vegetable protein diet with alpha-tocopherol acetate was effective in preventing the anomalous conditions described. The hatchability of turkey eggs from hens fed a diet adequate in known nutri-
61
VITAMIN E AND SELENIUM
TABLE 1.—Effect
Group 1 2 3 4 S 6 7 8 1 2
of various supplements on hatchability of eggs from BSW turkeys after a 9 weeks depletion period.
Supplement to basal diet
No. eggs set
0 0
230 174 199 147 209 289 295 308
1
5 % DBY 0.1 ppm. Se 5% DBY+0.1 ppm. Se 10 I.U. vitamin E/lb. 2 10 I.U. vitamin E/lb.+0.1 ppm.. Se 10 I.U. vitamin E/lb.+O.l ppm. S e + 5 % DBY
Dried brewer's yeast. D-alpha tocopheryl acetate.
% hatchabil% fertility ity of fertile eggs 41.3 62.0 74.3 56.4 75.1 82.0 74.9 89.6
42.1 50.0 51.3 51.8 52.8 65.8 62.8 67.7
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
thenate, 6 meg. vitamin B 12 , 160 mg. fertility of birds which had been reared MnS0 4 • 5H 2 0, and 400 mg. choline chlo- under practical conditions, but fed a diet ride. This diet is essentially the same diet without added vitamin E for a period of used by this laboratory to study vitamin E nine weeks (Group 2), was 62%. Howdeficiency in turkey hens during the past ever, when dried brewers yeast (5%) or several years. The supplements of dried vitamin E (10 I.U. per lb.) were added to brewers yeast, selenium and d-alpha tocoph- the diet, the fertility increased to 74.3% eryl acetate to the basal diet are indicated in and 82%, respectively. The addition of Table 1. Selenium was added in the form 0.1 ppm. of selenium resulted in a decrease in fertility of 5.6%. The combination of of sodium selenite. dried brewers yeast and selenium as a supHens were artificially inseminated twice plement was no better than when dried a month and one torn per 20 hens was brewers yeast alone was fed. When vitamin provided for natural mating. Toms were E was fed with selenium, the fertility was rotated between pens weekly to provide lower than when vitamin E alone was fed. maximum fertility. Eggs were collected It is interesting, however, that when vitatwice each day, stored in a cooler at S5°F., min E, selenium and dried brewers yeast and set at two-week intervals. Eggs were were added to the basal diet (Group 8), candled at 7, 14, 21 and 24 days, and all the resulting fertility of eggs was 89.6%, infertile eggs and those containing dead or 27.6% over that of the control group 2. embryos were removed so that time of The increase in fertility following suppleembryonic death could be determined. Eggs which were removed during incubation, mentation of the diet with vitamin E is in and those which failed to hatch on the 29th agreement with results reported by Ferday of incubation period were broken out guson et al. (1958). and a gross macroscopic examination was The greatest increase in hatchability due made of the embryos. to a single supplement to the basal diet was obtained when vitamin E was added. No RESULTS AND DISCUSSION increase in hatchability of eggs was obOnly 41.3% of the eggs in group 1 were tained when dried brewers yeast (5%) or fertile (Table 1). This group of hens were selenium (0.1 ppm.) were added. When progeny of hens maintained on a diet which selenium was fed with vitamin E, a slight did not contain added vitamin E. The decrease in hatchability occurred. Essen-
62
CREGER, MITCHELL, ATKINSON, FERGUSON, REID AND COUCH
SUMMARY
Beltsville Small White turkey hens, reared on range and fed a complete practical ration, were placed in wire floor pens and fed a diet low in vitamin E for the first nine weeks of the laying period. Supplements of dried brewers yeast, selenium and vitamin E were added for an additional twelve weeks of production. Supplementation of 5% dried brewers yeast to a basal diet deficient in vitamin E produced an increase in fertility, but had no effect on the hatchability of fertile eggs. The addition of 0.1 ppm. selenium appeared to produce a slight depression in fertility. Supplementation with 10 I.U. of vitamin E
per pound produced an increase in both the fertility and hatchability of fertile eggs. The addition of 0.1 ppm. selenium to the vitamin E-low diet showed no vitamin Elike activity. ACKNOWLEDGMENTS
This work was supported in part by a grant-in-aid from the Brewers Yeast Council, Inc., Chicago, Illinois. Dried brewers yeast was supplied by the Brewers Yeast Council, Inc., Chicago, Illinois; vitamin D 3 by Charles Bowman and Co., Holland, Michigan; niacin, riboflavin, calcium pantothenate and vitamin Bi2 by Merck and Co., Rahway, New Jersey; choline chloride by Hoffman-Taff, Inc., Springfield, Missouri; menadione sodium bisulfite by Heterochemical Corp., Valley Stream, New York; stabilized vitamin A by Stabilized Vitamins, Inc., Garfield, New Jersey; defluorinated phosphate by Butler Chemical Co., Galena Park, Texas; and d-alpha tocopheryl acetate by Distillation Products Industries, Rochester, New York. REFERENCES Atkinson, R. L., T. M. Ferguson, J. H. Quisenberry and J. R. Couch, 1955. Vitamin E and reproduction in turkeys. J. Nutr. 55: 387-397. Creech, B. G., G. L. Feldman, T. M. Ferguson, B. L. Reid and J. R. Couch, 1957. Exudative diathesis and vitamin E deficiency in turkey poults. J. Nutr. 62 : 83-96. Feldman, G. L., R. L. Atkinson, B. G. Creech, T. M. Ferguson, B. L. Reid and J. R. Couch, 1957. The effect of dehydrated alfalfa meal, dried brewers yeast and condensed fish solubles on the reproductive performance of turkeys. Poultry Sci. 36:792-797. Ferguson, T. M., R. L. Atkinson and J. R. Couch, 1954. The relationship of vitamin E to the embryonic development of the avian eye. Proc. Soc. Exp. Biol. Med. 86: 868-871. Ferguson, T. M., H. P. Vaught, B. L. Reid and J. R. Couch, 1956. The effect of vitamin E, dehydrated alfalfa meal and condensed fish solubles upon hatchability of eggs from Broad Breasted Bronze turkey hens maintained on litter. Poultry Sci. 35: 872-875.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
tially no improvement in hatchability was observed when dried brewers yeast and selenium were fed with vitamin E, over that obtained when vitamin E alone was fed. Feldman et al. (1957) reported a significant increase in the hatchability of fertile eggs from Broad Breasted Bronze hens when dried brewers yeast was added to the basal diet which contained supplemental vitamin E. The hens had been reared on range and fed a practical farm ration prior to being placed on experiment. The hens in the present study had been deprived of vitamin E and unidentified factors for the first nine weeks of their production period. Except for the fertility in group 8, the addition of selenium was of no apparent benefit in hatchability or fertility, and in most cases produced a slight depression of both criteria. The effect on hatchability and fertility was apparently due to the combined effects of dried brewers yeast and vitamin E since the combination of selenium with either dried brewers yeast or vitamin E had no benefit. Dried brewers yeast was effective in producing an increase in fertility, but was not as effective as vitamin E in increasing hatchability.
63
VITAMIN E AND SELENIUM Ferguson, T. M., R. L. Atkinson, G. L. Feldman, C. H. Whiteside, J. H. Quisenberry and J. R. Couch, 1958. The effect of unidentified factor sources, antibiotics and d-alpha tocopheryl acetate on the reproductive performance of Broad Breasted Bronze and Beltsville Small White turkeys. Texas Agricultural Experiment Station Bulletin 914, Tex. Agr. Expt. Sta. Jensen, L. S., 1953. Vitamin E, niacin and grass juice in turkey hen nutrition. Proc. Cornell Nutr. Conf., p. 62. Patterson, E. L., R. Milstrey and E. L. R. Stok-
stad, 1957. Effects of selenium in preventing exudative diathesis in chicks. Proc. Soc. Exp. Biol. Med. 95: 617-620. Reid, B. L., M. M. Rahman, B. G. Creech and J. R. Couch, 1958. Selenium and development of exudative diathesis in chicks. Proc. Soc. Exp. Biol. Med. 97: 590-593. Schwartz, K., J. G. Bieri, G. M. Briggs and M. L. Scott, 1957. Prevention of exudative diathesis in chicks by factor 3 and selenium. Proc. Soc. Exp. Biol. Med. 95: 621-625.
R. N. SHOFFNER AND R. E. GRANT Minnesota Agricultural Experiment Station, St. Paul, and Northeast Branch Agricultural Experiment Station, Duluth (Received for publication May 19, 1959)
T
HE technique of relaxing selection by random mating in a population or sample of the population after selection for particular traits has a number of useful purposes. The most significant of these is answering the question; how permanent are the genetic gains in the selected trait? From a commercial point of view, if such gains are permanent a purchaser of chicks could keep on reproducing them for a considerable time without loss of performance. This technique has been used by geneticists in selection experiments to help shed light on a number of factors which affect selection. A principal consideration is some estimation of the effect of natural selection which opposes artificial selection if there is negative correlation between the selected trait and fitness components. The subject of relaxed or attenuated selection is discussed rather extensively by Lerner (1950) and by other authors in recent reports of selection experiments. * Published as Paper No. 4150. Scientific Journal Series of the Minnesota Agricultural Experiment Station, St. Paul 1, Minnesota.
The objective of this study was to observe and measure empirically the results of relaxed selection in a strain of White Leghorns previously selected for egg production. The physical facilities available made it impossible to compare more than three generations. DESIGN
The genetic stock on which these comparisons were made was secured from a commercial breeder who has been selecting for egg production as well as egg quality factors for a period of approximately twenty-five generations. During this time individual and family selections were made on a closed flock basis. While there is no accurate estimate of how much progress has been made, undoubtedly some has, since this particular stock is well accepted and enjoys a good reputation among commercial egg producers. It was suspected that the parent population performance had reached a plateau since comparative records of the past few years indicated little or no change in egg numbers. During the
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
Relaxed Selection in a Strain of White Leghorns *
EFFECT OF KIDNEYS ON SHELF-LIFE TABLE 8.—Plate counts of inoculum from kidneys and livers Kidney
Liver
No. colonies per plate
No. plates
0 1 2 4 5 Discarded lab errors
8 6 1 1 1 2
% of total plates
No. colonies per plate
42 31 •S 5 5 10
No. plates
% of total plates
16 2 1
84.2 10.S 5.2
average weight increase from chilling 10week old fryers in ice slush for 4 hours was 4.02% for those with kidneys and 5.29% for those without kidneys which difference was significant at the 1% level of probability. Shelf-life was extended on the average SUMMARY by 1.27 days with fryers which had the Tests were conducted to determine the kidneys removed. Approximately 42% of the plates with average loss in warm eviscerated yields of 8-week old broilers, 10-week old fryers, and inoculum from kidneys and 84% of those one-year old S. C. White Leghorn fowl be- from livers showed no colonies. Part of the fore and after kidney removal. The percent plates with growth had only one colony, loss in yield from kidney removal was which appeared to be Bacillus mycoides. 0.82% for the 8-week old broilers, approxi- The largest number of bacterial colonies in mately 0.70% for each group of 10-week any of the plates did not exceed 5. Other old fryers, and 0.66% for the S. C. White tests need to be conducted under plant conLeghorn fowl. These differences were sig- ditions to further evaluate kidney removal nificant at the 1 % level of probability. The from poultry carcasses.
Vitamin E Activity of Selenium in Turkey Hatchability C. R. CEEGER, R. H. MITCHELL, R. L. ATKINSON, T. M FERGUSON, Departments
B. L. REID AND J. R. COUCH of Biochemistry and Nutrition and Poultry Science, Texas A & M College, College Station, Texas (Received for publication May 19, 1959)
INTRODUCTION
NUMBER of workers have reported the vitamin E-like activity of selenium in preventing exudative diathesis in chicks (Schwartz et al., 1957; Reid et al., 1958; and Patterson et al., 1957). Schwartz
A
et al. (1957) reported dried brewers yeast and vitamin-free casein completely prevented symptoms of exudative diathesis and promoted good growth when fed at the 10% level in the diet of rats. They also reported the presence of a factor 3, which
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
the results of contamination, it seems logical to assume that bacterially infected tissue would give more colonies per plate than the number observed. Of course, viruses could have been present in the agar without being noticeable.
60
CEEGER, MITCHELL, ATKINSON, FERGUSON, REID AND COUCH
ents has been found to decrease after 8 to 12 weeks of egg production if the diet is not fortified with vitamin E and unidentified factor sources (Atkinson et al., 1955; Ferguson et al., 1956; Feldman, 1957). The present experiment was designed to determine the effects of supplements of selenium, dried brewers yeast and d-alpha tocopheryl acetate on the reproductive performance of Beltsville Small White turkey hens maintained on wire floors. The supplements were added to the diet at the end of a nine-week laying period, during which time all groups were fed a diet which was low in vitamin E and contained no unidentified factor sources. METHODS One hundred-forty Beltsville Small White turkey hens were divided into 7 groups of 20 birds each and placed in 12 ft. X 15 ft. pens with raised wire floors. Twenty additional hens (group 1) were progeny of birds which had been maintained on wire, and fed vitamin E-low diets for 5 generations. The birds in groups 2 through 8 had been reared to maturity on the range of the Texas Agricultural Experiment Station poultry farm and had been fed a practical diet containing adequate amounts of known nutrients, antibiotics and sources of unidentified growth factors. All groups were fed a diet low in vitamin E for 9 weeks prior to the initiation of the experiment; groups 1 and 2 were maintained on this diet throughout the twelve-week experimental period. The composition of the basal diet was as follows: 25% soybean oil meal, 69% ground milo, 3 % defluorinated phosphate, 2.5% ground oyster shell, and 0.5% sodium chloride. The following were added per pound of feed: 9,000 I.U. vitamin A (stabilized), 1,200 I.C.U. vitamin D 3 , 1 mg. menadione sodium bisulfite, 20 mg. niacin, 2 mg. riboflavin, 12.5 mg. calcium pantho-
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
they described as, "The biologically active, selenium containing component, or components, present in nutrients and other materials of biological origin," to be present in dried brewers yeast. Creech et al. (1957) showed that exudative diathesis, produced in Beltsville Small White turkey poults, could be prevented by the addition of alpha-tocopherol acetate to the diet. Dried brewers yeast was also found to prevent this condition. These investigators determined the relationship between serum protein of the poult and the supplements to the diets of the dams. Results demonstrated that supplementation of the synthetic maternal diet with dried brewers yeast or alpha-tocopherol acetate significantly increased the A/G ratio over that of poults from dams on vitamin E low diets. Creech and co-workers also reported that the factor in dried brewers yeast was transmitted to a high degree from the dam through the egg to the poult, and was effective in preventing exudative diathesis. Atkinson et al. (1955) reported a 36% increase in hatchability when alpha-tocopherol acetate was added to a low vitamin E diet for Beltsville Small White turkey hens. An increase in hatchability was also obtained by Ferguson et al. (1956) when vitamin E was added as a supplement to the diet of Broad Breasted Bronze turkey hens. Jensen (1953) reported beneficial effects on hatchability of eggs from Empire White turkey hens when vitamin E was supplemented to the diet. Ferguson et al. (1954) reported certain abnormalities of the eye of Beltsville Small White turkey embryos obtained from eggs of hens fed a diet low in vitamin E. Supplementation of the all-vegetable protein diet with alpha-tocopherol acetate was effective in preventing the anomalous conditions described. The hatchability of turkey eggs from hens fed a diet adequate in known nutri-
61
VITAMIN E AND SELENIUM
TABLE 1.—Effect
Group 1 2 3 4 S 6 7 8 1 2
of various supplements on hatchability of eggs from BSW turkeys after a 9 weeks depletion period.
Supplement to basal diet
No. eggs set
0 0
230 174 199 147 209 289 295 308
1
5 % DBY 0.1 ppm. Se 5% DBY+0.1 ppm. Se 10 I.U. vitamin E/lb. 2 10 I.U. vitamin E/lb.+0.1 ppm.. Se 10 I.U. vitamin E/lb.+O.l ppm. S e + 5 % DBY
Dried brewer's yeast. D-alpha tocopheryl acetate.
% hatchabil% fertility ity of fertile eggs 41.3 62.0 74.3 56.4 75.1 82.0 74.9 89.6
42.1 50.0 51.3 51.8 52.8 65.8 62.8 67.7
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
thenate, 6 meg. vitamin B 12 , 160 mg. fertility of birds which had been reared MnS0 4 • 5H 2 0, and 400 mg. choline chlo- under practical conditions, but fed a diet ride. This diet is essentially the same diet without added vitamin E for a period of used by this laboratory to study vitamin E nine weeks (Group 2), was 62%. Howdeficiency in turkey hens during the past ever, when dried brewers yeast (5%) or several years. The supplements of dried vitamin E (10 I.U. per lb.) were added to brewers yeast, selenium and d-alpha tocoph- the diet, the fertility increased to 74.3% eryl acetate to the basal diet are indicated in and 82%, respectively. The addition of Table 1. Selenium was added in the form 0.1 ppm. of selenium resulted in a decrease in fertility of 5.6%. The combination of of sodium selenite. dried brewers yeast and selenium as a supHens were artificially inseminated twice plement was no better than when dried a month and one torn per 20 hens was brewers yeast alone was fed. When vitamin provided for natural mating. Toms were E was fed with selenium, the fertility was rotated between pens weekly to provide lower than when vitamin E alone was fed. maximum fertility. Eggs were collected It is interesting, however, that when vitatwice each day, stored in a cooler at S5°F., min E, selenium and dried brewers yeast and set at two-week intervals. Eggs were were added to the basal diet (Group 8), candled at 7, 14, 21 and 24 days, and all the resulting fertility of eggs was 89.6%, infertile eggs and those containing dead or 27.6% over that of the control group 2. embryos were removed so that time of The increase in fertility following suppleembryonic death could be determined. Eggs which were removed during incubation, mentation of the diet with vitamin E is in and those which failed to hatch on the 29th agreement with results reported by Ferday of incubation period were broken out guson et al. (1958). and a gross macroscopic examination was The greatest increase in hatchability due made of the embryos. to a single supplement to the basal diet was obtained when vitamin E was added. No RESULTS AND DISCUSSION increase in hatchability of eggs was obOnly 41.3% of the eggs in group 1 were tained when dried brewers yeast (5%) or fertile (Table 1). This group of hens were selenium (0.1 ppm.) were added. When progeny of hens maintained on a diet which selenium was fed with vitamin E, a slight did not contain added vitamin E. The decrease in hatchability occurred. Essen-
62
CREGER, MITCHELL, ATKINSON, FERGUSON, REID AND COUCH
SUMMARY
Beltsville Small White turkey hens, reared on range and fed a complete practical ration, were placed in wire floor pens and fed a diet low in vitamin E for the first nine weeks of the laying period. Supplements of dried brewers yeast, selenium and vitamin E were added for an additional twelve weeks of production. Supplementation of 5% dried brewers yeast to a basal diet deficient in vitamin E produced an increase in fertility, but had no effect on the hatchability of fertile eggs. The addition of 0.1 ppm. selenium appeared to produce a slight depression in fertility. Supplementation with 10 I.U. of vitamin E
per pound produced an increase in both the fertility and hatchability of fertile eggs. The addition of 0.1 ppm. selenium to the vitamin E-low diet showed no vitamin Elike activity. ACKNOWLEDGMENTS
This work was supported in part by a grant-in-aid from the Brewers Yeast Council, Inc., Chicago, Illinois. Dried brewers yeast was supplied by the Brewers Yeast Council, Inc., Chicago, Illinois; vitamin D 3 by Charles Bowman and Co., Holland, Michigan; niacin, riboflavin, calcium pantothenate and vitamin Bi2 by Merck and Co., Rahway, New Jersey; choline chloride by Hoffman-Taff, Inc., Springfield, Missouri; menadione sodium bisulfite by Heterochemical Corp., Valley Stream, New York; stabilized vitamin A by Stabilized Vitamins, Inc., Garfield, New Jersey; defluorinated phosphate by Butler Chemical Co., Galena Park, Texas; and d-alpha tocopheryl acetate by Distillation Products Industries, Rochester, New York. REFERENCES Atkinson, R. L., T. M. Ferguson, J. H. Quisenberry and J. R. Couch, 1955. Vitamin E and reproduction in turkeys. J. Nutr. 55: 387-397. Creech, B. G., G. L. Feldman, T. M. Ferguson, B. L. Reid and J. R. Couch, 1957. Exudative diathesis and vitamin E deficiency in turkey poults. J. Nutr. 62 : 83-96. Feldman, G. L., R. L. Atkinson, B. G. Creech, T. M. Ferguson, B. L. Reid and J. R. Couch, 1957. The effect of dehydrated alfalfa meal, dried brewers yeast and condensed fish solubles on the reproductive performance of turkeys. Poultry Sci. 36:792-797. Ferguson, T. M., R. L. Atkinson and J. R. Couch, 1954. The relationship of vitamin E to the embryonic development of the avian eye. Proc. Soc. Exp. Biol. Med. 86: 868-871. Ferguson, T. M., H. P. Vaught, B. L. Reid and J. R. Couch, 1956. The effect of vitamin E, dehydrated alfalfa meal and condensed fish solubles upon hatchability of eggs from Broad Breasted Bronze turkey hens maintained on litter. Poultry Sci. 35: 872-875.
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
tially no improvement in hatchability was observed when dried brewers yeast and selenium were fed with vitamin E, over that obtained when vitamin E alone was fed. Feldman et al. (1957) reported a significant increase in the hatchability of fertile eggs from Broad Breasted Bronze hens when dried brewers yeast was added to the basal diet which contained supplemental vitamin E. The hens had been reared on range and fed a practical farm ration prior to being placed on experiment. The hens in the present study had been deprived of vitamin E and unidentified factors for the first nine weeks of their production period. Except for the fertility in group 8, the addition of selenium was of no apparent benefit in hatchability or fertility, and in most cases produced a slight depression of both criteria. The effect on hatchability and fertility was apparently due to the combined effects of dried brewers yeast and vitamin E since the combination of selenium with either dried brewers yeast or vitamin E had no benefit. Dried brewers yeast was effective in producing an increase in fertility, but was not as effective as vitamin E in increasing hatchability.
63
VITAMIN E AND SELENIUM Ferguson, T. M., R. L. Atkinson, G. L. Feldman, C. H. Whiteside, J. H. Quisenberry and J. R. Couch, 1958. The effect of unidentified factor sources, antibiotics and d-alpha tocopheryl acetate on the reproductive performance of Broad Breasted Bronze and Beltsville Small White turkeys. Texas Agricultural Experiment Station Bulletin 914, Tex. Agr. Expt. Sta. Jensen, L. S., 1953. Vitamin E, niacin and grass juice in turkey hen nutrition. Proc. Cornell Nutr. Conf., p. 62. Patterson, E. L., R. Milstrey and E. L. R. Stok-
stad, 1957. Effects of selenium in preventing exudative diathesis in chicks. Proc. Soc. Exp. Biol. Med. 95: 617-620. Reid, B. L., M. M. Rahman, B. G. Creech and J. R. Couch, 1958. Selenium and development of exudative diathesis in chicks. Proc. Soc. Exp. Biol. Med. 97: 590-593. Schwartz, K., J. G. Bieri, G. M. Briggs and M. L. Scott, 1957. Prevention of exudative diathesis in chicks by factor 3 and selenium. Proc. Soc. Exp. Biol. Med. 95: 621-625.
R. N. SHOFFNER AND R. E. GRANT Minnesota Agricultural Experiment Station, St. Paul, and Northeast Branch Agricultural Experiment Station, Duluth (Received for publication May 19, 1959)
T
HE technique of relaxing selection by random mating in a population or sample of the population after selection for particular traits has a number of useful purposes. The most significant of these is answering the question; how permanent are the genetic gains in the selected trait? From a commercial point of view, if such gains are permanent a purchaser of chicks could keep on reproducing them for a considerable time without loss of performance. This technique has been used by geneticists in selection experiments to help shed light on a number of factors which affect selection. A principal consideration is some estimation of the effect of natural selection which opposes artificial selection if there is negative correlation between the selected trait and fitness components. The subject of relaxed or attenuated selection is discussed rather extensively by Lerner (1950) and by other authors in recent reports of selection experiments. * Published as Paper No. 4150. Scientific Journal Series of the Minnesota Agricultural Experiment Station, St. Paul 1, Minnesota.
The objective of this study was to observe and measure empirically the results of relaxed selection in a strain of White Leghorns previously selected for egg production. The physical facilities available made it impossible to compare more than three generations. DESIGN
The genetic stock on which these comparisons were made was secured from a commercial breeder who has been selecting for egg production as well as egg quality factors for a period of approximately twenty-five generations. During this time individual and family selections were made on a closed flock basis. While there is no accurate estimate of how much progress has been made, undoubtedly some has, since this particular stock is well accepted and enjoys a good reputation among commercial egg producers. It was suspected that the parent population performance had reached a plateau since comparative records of the past few years indicated little or no change in egg numbers. During the
Downloaded from http://ps.oxfordjournals.org/ at North Dakota State University on May 23, 2015
Relaxed Selection in a Strain of White Leghorns *