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Reproductive Performance of White Leghorns Provided Fluoride
Reproductive Performance of White Leghorns Provided Fluoride J. W. MERKLEY
US Department of Agriculture, Science and Education Administration, Agricultural Research, Poultry Research Laboratory, RD 2, Box 600, Georgetown, Delaware 19947 T. J. SEXTON Avian Physiology Laboratory, Beltsville, Maryland 20705 (Received for publication April 27, 1981) ABSTRACT Two trials were conducted to determine if added sodium fluoride in the drinking water of chickens would result in any deleterious effects on reproduction. In both trials 120 individually caged Single Comb White Leghorn hens (SCWL) were used. Experimental groups consisted of a control group which received no fluoride and three treated groups which received 100 parts per million (ppm) fluoride during either the growing period (0 to 20 weeks), production period (from 20 weeks on), or continuously from day 1. In Trial 1 broiler-breeder males that had not been treated with supplemental fluoride were used as the source of semen for artificial insemination. In Trial 2 half the SCWL cockerels used had been treated with 100 ppm F in the drinking water from day 1. The reproductive characteristics measured were egg production, fertility, duration of fertility, and hatchability of fertile eggs. No deleterious effects due to fluoride exposure at the 100 ppm level in the drinking water were observed in the reproductive performance of either pullets or cockerels. Egg production in both trials decreased slightly during the insemination periods in all experimental groups of pullets. Birds hatched from the various treatment groups in Trial 1 were raised to 4 weeks of age, and no effects of fluoride on progeny growth were noted. (Key words: hens, fluoride, fertility, hatchability) 1982 Poultry Science 61:52-56 INTRODUCTION Usually the presence of fluoride has been discussed only in regard to its toxicity. As late as 1978, Cakir et al. reported the beneficial use of aluminum in the starting diets of turkeys and chickens to alleviate fluoride toxicity. However, fluoride may not be as deleterious in poultry diets as was once generally assumed. Moderate levels of fluoride (100 to 300 ppm) could prove to be beneficial in several ways. Merkley (1976) reported an increase in bone strength and percentage of bone ash when 100 ppm F was provided as sodium fluoride in the drinking water of cage-reared broilers. The breakage of bones during the processing of spent hens and cage-reared broilers is a very costly condition that must be accepted by the processor. With spent hens the problem is intensified by the possible occurrence of bone fragments in the deboned meat. This development of bone fragility in cage-reared broilers and layers is often explained as a result of insufficient exercise due to the physical restriction of the cage on the mobility of chickens. Rowland and Harms (1970) indicated that the
development of fragile bones in caged layers was not due to a nutritional deficiency or imbalance but probably was a result of restricted activity. Meyer and Sunde (1974) reported an increase in the bone strength of caged layers that were forced to exercise in a treadmill. The use of dietary fluoride to strengthen and prevent the large incidence of broken bones during the processing of spent layers would not only be desirable but also of possible economic importance. Economic benefits would also be realized if sources of phosphate containing natural levels of fluoride could be used in poultry diets. The process of defluorinating raw rock phosphate is expensive and potentially hazardous to the environment. Said et al. (1979) concluded that the use of raw rock phosphate containing fluoride in the diet of laying hens was possible without any noticeably harmful effects. Earlier research reported by Merkley (1978) showed that fluoride in the drinking water of maturing hens increased bone strength and egg production and quality were not adversely affected. Kuhl and Sullivan (1976) showed an increase in egg production 52
FLUORIDE FERTILITY STUDY and egg weight with no depression in feed efficiency when laying diets were supplemented with sodium fluoride and high fluoride fertilizer phosphates. The use of fluoride in the diet of breeder flocks, for example, is of interest for two reasons. Fluoride supplementation might help prevent leg problems, especially in heavy birds maintained in cages for artificial insemination. Second, there is a need to determine the effect of fluoride fed to the adult on the subsequent developing embryo. The lack of information on the deleterious effects of fluoride on the reproductive performance of breeders and their progeny resulted in this study. The'purpose of this research was to determine the effect of added fluoride in the drinking water of chickens either during the growing or production period and during the entire life cycle of the bird on the reproductive performance of Single Comb White Leghorns (SCWL).
EXPERIMENTAL PROCEDURES Two trials were conducted using DeKalb XL-Link 1 SCWL pullets. The birds for both trials were obtained at 1 day of age from a commercial hatchery. They were wing banded, weighed, and randomly placed in one of two floor pens on fresh pine shavings. Chickens in one pen were given 50 ppm fluoride in the drinking water, and after the 1st week the level was increased to 100 ppm for the duration of the experiment. The fluoride used was provided as sodium fluoride diluted in distilled water. The other pen of chickens in each trial received tap water and served as controls for comparison. This source of water contained less than .1 ppm fluoride. The diets used were standard corn-soybean meal diets obtained from a local feed mill. Feed and water were provided ad libitum during the entire experiment. The diets were analyzed for their fluoride content, which was found to vary with the batch of feed mixed and ranged from 2 to 10 ppm during the study. When the pullets reached 20 weeks of age, they were transferred to individual cages in one of two laying batteries, each holding 60 birds.
1 Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.
53
Pullets that did not come into production during the first 3 weeks in cages were replaced with similarly treated birds from the floor pens. The hens in one battery, half of which came from each of the two floor pens, received distilled water containing 100 ppm fluoride. The other battery of hens, half of which came from each of the two floor pens, received only tap water during the remainder of the study. Four experimental groups of laying hens were therefore established: one group of birds served as controls (C-C) and had received no supplemental fluoride; another group of laying hens received fluoride during both the growing and laying period (F-F); the remaining two groups of birds received fluoride only during one of the two periods, either during the growing (F-C) or the laying (C-F) period. This experimental design has been described in previous work (Merkley, 1981). The pullets were maintained under conventional cage housing conditions with a lighting schedule of 15 hr per day in a windowless room. In the first trial the hens were force molted by feed and water restriction at 13 months of age, before being inseminated at 15 months of age. Hens in the second trial were inseminated at 11 months of age. In Trial 1 no SCWL males were available, and broiler breeder roosters were obtained from several sources. They were placed in individual cages and provided the same commercial laying diet given the pullets and tap water ad libitum. After a brief adjustment period in the new environment, they served as the semen source. In Trial 2 DeKalb SCWL cockerels were obtained at 1 day old and wing banded. They were divided into two floor pens. One pen of birds served as control cockerels and received tap water. The other pen of cockerels was treated with fluoride in the same manner as the pullets. Two weeks before starting semen collection in Trial 2, 30 males from each group were individually caged in modified laying batteries to allow increased head room as were the broiler breeder cockerels in Trial 1. The cockerels were 8 months old when the pullets were inseminated in Trial 2 at 11 months of age. In both trials pooled semen was collected and diluted 1:1 with the Beltsville Poultry Semen Extender (Sexton, 1977). The last insemination of Trial 1 necessitated a 1:3 dilution because of a reduced semen yield that particular day. The hens were inseminated with
54
MERKLEY AND SEXTON
.05 ml of diluted semen on three separate days. In both trials the hens were inseminated 3 and 11 days after the initial insemination. Eggs were collected daily starting 24 hr after the initial insemination in both trials. The eggs were stored at 13 C (55 F) with a relative humidity of 60 to 70%. Eggs were stored no longer than 4 days prior to incubation. All eggs determined to be infertile or fertile dead on day seven of incubation were broken out and any eggs showing signs of embryo growth were scored as early dead. The presence of blood was the major criterion measured. The percent true fertility is expressed as the number of fertile eggs plus early dead embryos divided by the total number of eggs set. The percent hatchability is expressed as the total number of chicks produced from fertile eggs transferred on day 19 of incubation. The range of percentages did not warrant any transformation of the data, and straight percentages were used in the analysis of variance and Duncan's multiple range test (Snedecor and Cochran, 1968) in both trials.
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There was no statistically significant difference in the percentage of egg production among the four experimental groups of hens prior to the initial insemination in Trial 1 (Table 1). During the 1 month period in which eggs were collected for incubation, the rate of production decreased. Since all groups showed a similar decrease in production, there were no significant differences in the production rates among the
TH
H
RESULTS AND DISCUSSION
There was a difference in the number of hens in each experimental group in Trial 1 (Table 1). The fewer hens used in the F-F group can be attributed to several culling criteria unrelated to the experimental treatment. One hen failed to lay a fertile egg and was eliminated, since at each insemination a hard shelled egg had been present in the oviduct. Another hen laid only eggs with deformed shells, and this appeared to affect hatchability. No inference can be drawn concerning the influence of fluoride on the number of hens suitable as experimental subjects in this trial. Among the hens that remained in the floor pens, there appeared to be no differences in their livability or production ability due to fluoride intake. In previous work no significant effects were found on egg production or egg quality in fluoride treated hens (Guenter, 1979; Merkley, 1981).
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FLUORIDE FERTILITY STUDY
experimental groups during the period in which eggs were collected for incubation. This decrease probably resulted from handling the birds during insemination to which the birds were unaccustomed; it was observed that the month following the experimental period in which eggs were collected all groups showed a similar increase in egg production. As shown in Table 1, there were no statistically significant differences in fertility, hatchability, and duration of fertility among the experimental groups in Trial 1. The total number of embryos classified as late hatching and pips was extremely low (<.6%). From the more than 2400 chicks hatched during Trial 1, approximately 500 from two hatches were randomly selected and raised to 4 weeks of age using standard broiler feed and tap water. No differences were observed in the 4 week growth of chicks from the four experimental groups. Mortality was very low, and no visible leg problems developed regardless of the parental treatments. A wide range of phenotypes was readily apparent. Straight run broilers would be expected to weigh approximately 800 g at 4 weeks and Leghorns approximately 300 g. The 4-week weights (Table 2) of these chicks were between these extremes. In Trial 2, as had been observed in Trial 1, there was a drop in the egg production during the insemination period. This drop was not as great as that in the first trial which might be accounted for by the use of younger hens in Trial 2. At no time was there a significant difference in egg production between the experimental groups. In the second trial, the four experimental
TABLE 2. Four-week progeny weight from Leghorn hens fed fluoride (Trial 1) Hen treatment
Hatch 2
Hatch 3
Fluoride F-F
507 ± 5.5 1 (106) 2 1 3
457 + 4.4 (141)5
Control C-C
496 + 5.9 (90)1
464 ± 5.1 (116)0
1
Mean and SEM expressed in grams.
2
Number of chicks weighed at 4 weeks.
3
Number of chicks that died from 0 to 4 weeks.
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MERKLEY AND SEXTON
groups indicated in-Table 3 were different from those in Table 1 (Trial 1). T h e cockerels used in Trial 2 were from t w o t r e a t m e n t groups. Half had been treated with fluoride and were continuing t o receive fluoride in t h e drinking water at the time of semen collection. T h e o t h e r half of SCWL cockerels served as controls and had received n o fluoride s u p p l e m e n t a t i o n . Since t h e p a t t e r n of fluoride exposure had n o significant effect on t h e hens in Trial 1, these pullets were grouped by t h e t r e a t m e n t t h e y were receiving at the time of insemination. T h e experimental groups used in Trial 2 (Table 3) were designated b y t h e t r e a t m e n t of t h e males and females during their period in t h e cages.
However, this could n o t be avoided and m i g h t be a reason for t h e seemingly low fertility levels experienced. T h e results of this s t u d y should encourage further studies with fluoride s u p p l e m e n t a t i o n with larger n u m b e r s of birds including studies u n d e r commercial conditions.
There were n o differences in t h e weights of t h e pullets and cockerels in t h e four experim e n t a l groups ( F 9 - F d , C9-C<5, F9-C<5, C9-Fd) at t h e t i m e of insemination in trial 2. T h e pullets n o t receiving fluoride h a d an average weight of 1815 g and those receiving fluoride 1811 g. T h e control cockerels averaged 2 2 2 2 g and those receiving fluoride 2 1 9 4 g. It is k n o w n t h a t fluoride at levels t h a t d o n o t affect b o d y weights can change o t h e r physiological parameters, such as ascorbic acid levels in tissues of y o u n g chickens (Yu and Driver, 1 9 7 8 ) .
Cakir, A., T. W. Sullivan, and F. B. Mather, 1978. Alleviation of fluoride toxicity in starting turkeys and chicks with aluminum. Poultry Sci. 57: 498-505. Giesen, A. F., G. R. McDaniel, and T. J. Sexton, 1980. Effect of time of day of artificial insemination and oviposition-insemination interval on the fertility of broiler breeder hens. Poultry Sci. 59: 2544-2549. Guenter, W., 1979. Fluorine toxicity and laying hen performance. Poultry Sci. 58:1063. Kuhl, H. J., Jr., and T. W. Sullivan, 1976. Effect of sodium fluoride and high fluoride fertilizer phosphates on performance of laying chickens and egg shell quality. Poultry Sci. 55:2055. (Abstr.) Merkley, J. W., 1976. Increased bone strength in coop-reared broilers provided fluoridated water. Poultry Sci. 55:1313-1319. Merkley, J. W., 1978. Increased bone strength in caged layers provided fluoride. Vol. VI ( J - l l ) . Proc. XVi World's Poultry Congr., Rio de Janeiro, Brazil. Merkley, J. W., 1981. The effect of sodium fluoride on egg production, egg quality, and bone strength of caged layers. Poultry Sci. 60:771—776. Meyer, W. A., and M. L. Sunde, 1974. Bone breakage as affected by type of housing or an exercise machine for layers. Poultry Sci. 53:878-885. Phillips, P. H„ D. A. Greenwood, C. S. Hobbs, C. F. Huffman, and G. R. Spencer, 1960. The fluoride problem in livestock production. Rep. Committee Anim. Nutr. NAS-NRC Bull. 824, Washington, DC. Rowland, L. O., Jr., and R. H. Harms, 1970. The effect of wire pens, floor pens, and cages on bone characteristics of laying hens. Poultry Sci. 49: 1223-1225. Said, N. W., M. L. Sunde, H. R. Bird, and J. W. Suttie, 1979. Raw rock phosphate as a phosphorus supplement for growing pullets and layers. Poultry Sci. 58:1557-1563. Sexton, T. J., 1977. A new poultry semen extender. I. Effect of extension on the fertility of chicken semen. Poultry Sci. 56:1443—1446. Snedecor, G. W., and W. G. Cochran, 1968. Statistical methods. Iowa State Univ. Press, Ames, IA. Yu, M. H., and C. J. Driver, 1978. The effects of fluoride on the growth of 1-ascorbic acid levels of tissues from the domestic chicken (Gallus domesticus). Fluoride 11:60-67.
T h e c o n c e n t r a t i o n of 100 p p m fluoride in t h e drinking water is considered t o be less t h a n t h e m a x i m u m safe range of 3 0 0 t o 4 0 0 p p m when provided in t h e feed (Phillips et al., 1960). When c o m p a r e d t o t h e control chickens, fluoride s u p p l e m e n t a t i o n at a level (100 p p m ) which significantly increases b o n e strength and percent b o n e ash (Merkley, 1981) had n o observable effect o n t h e reproductive characteristics of pullets or cockerels. In trial 2 , where b o t h pullets and cockerels were continuously treated from one day of age with sodium fluoride, t h e results did n o t differ from t h a t of control birds. T h e fertility and hatchability results r e p o r t e d in this trial were lower t h a n e x p e c t e d . T h e percent hatchability in all eggs transferred was lower in Trial 2 t h a n in Trial 1. This reduced hatchability was unrelated t o t h e e x p e r i m e n t a l t r e a t m e n t s and m a y have been due t o difficulties experienced in maintaining p r o p e r h u m i d i t y in t h e incubators. F o r e x a m p l e , there was a high percentage of pips observed in all four g r o u p s : 15.6, 1 2 . 3 , 10.3, and 12.8 for t h e F9-F
ACKNOWLEDGMENT T h e a u t h o r s wish t o express their appreciation to D . M. Gavelek, S.Wildermuth, and V. W. S m o o t for their skilled technical assistance in t h e artificial insemination of t h e experimental birds.
REFERENCES
US Department of Agriculture, Science and Education Administration, Agricultural Research, Poultry Research Laboratory, RD 2, Box 600, Georgetown, Delaware 19947 T. J. SEXTON Avian Physiology Laboratory, Beltsville, Maryland 20705 (Received for publication April 27, 1981) ABSTRACT Two trials were conducted to determine if added sodium fluoride in the drinking water of chickens would result in any deleterious effects on reproduction. In both trials 120 individually caged Single Comb White Leghorn hens (SCWL) were used. Experimental groups consisted of a control group which received no fluoride and three treated groups which received 100 parts per million (ppm) fluoride during either the growing period (0 to 20 weeks), production period (from 20 weeks on), or continuously from day 1. In Trial 1 broiler-breeder males that had not been treated with supplemental fluoride were used as the source of semen for artificial insemination. In Trial 2 half the SCWL cockerels used had been treated with 100 ppm F in the drinking water from day 1. The reproductive characteristics measured were egg production, fertility, duration of fertility, and hatchability of fertile eggs. No deleterious effects due to fluoride exposure at the 100 ppm level in the drinking water were observed in the reproductive performance of either pullets or cockerels. Egg production in both trials decreased slightly during the insemination periods in all experimental groups of pullets. Birds hatched from the various treatment groups in Trial 1 were raised to 4 weeks of age, and no effects of fluoride on progeny growth were noted. (Key words: hens, fluoride, fertility, hatchability) 1982 Poultry Science 61:52-56 INTRODUCTION Usually the presence of fluoride has been discussed only in regard to its toxicity. As late as 1978, Cakir et al. reported the beneficial use of aluminum in the starting diets of turkeys and chickens to alleviate fluoride toxicity. However, fluoride may not be as deleterious in poultry diets as was once generally assumed. Moderate levels of fluoride (100 to 300 ppm) could prove to be beneficial in several ways. Merkley (1976) reported an increase in bone strength and percentage of bone ash when 100 ppm F was provided as sodium fluoride in the drinking water of cage-reared broilers. The breakage of bones during the processing of spent hens and cage-reared broilers is a very costly condition that must be accepted by the processor. With spent hens the problem is intensified by the possible occurrence of bone fragments in the deboned meat. This development of bone fragility in cage-reared broilers and layers is often explained as a result of insufficient exercise due to the physical restriction of the cage on the mobility of chickens. Rowland and Harms (1970) indicated that the
development of fragile bones in caged layers was not due to a nutritional deficiency or imbalance but probably was a result of restricted activity. Meyer and Sunde (1974) reported an increase in the bone strength of caged layers that were forced to exercise in a treadmill. The use of dietary fluoride to strengthen and prevent the large incidence of broken bones during the processing of spent layers would not only be desirable but also of possible economic importance. Economic benefits would also be realized if sources of phosphate containing natural levels of fluoride could be used in poultry diets. The process of defluorinating raw rock phosphate is expensive and potentially hazardous to the environment. Said et al. (1979) concluded that the use of raw rock phosphate containing fluoride in the diet of laying hens was possible without any noticeably harmful effects. Earlier research reported by Merkley (1978) showed that fluoride in the drinking water of maturing hens increased bone strength and egg production and quality were not adversely affected. Kuhl and Sullivan (1976) showed an increase in egg production 52
FLUORIDE FERTILITY STUDY and egg weight with no depression in feed efficiency when laying diets were supplemented with sodium fluoride and high fluoride fertilizer phosphates. The use of fluoride in the diet of breeder flocks, for example, is of interest for two reasons. Fluoride supplementation might help prevent leg problems, especially in heavy birds maintained in cages for artificial insemination. Second, there is a need to determine the effect of fluoride fed to the adult on the subsequent developing embryo. The lack of information on the deleterious effects of fluoride on the reproductive performance of breeders and their progeny resulted in this study. The'purpose of this research was to determine the effect of added fluoride in the drinking water of chickens either during the growing or production period and during the entire life cycle of the bird on the reproductive performance of Single Comb White Leghorns (SCWL).
EXPERIMENTAL PROCEDURES Two trials were conducted using DeKalb XL-Link 1 SCWL pullets. The birds for both trials were obtained at 1 day of age from a commercial hatchery. They were wing banded, weighed, and randomly placed in one of two floor pens on fresh pine shavings. Chickens in one pen were given 50 ppm fluoride in the drinking water, and after the 1st week the level was increased to 100 ppm for the duration of the experiment. The fluoride used was provided as sodium fluoride diluted in distilled water. The other pen of chickens in each trial received tap water and served as controls for comparison. This source of water contained less than .1 ppm fluoride. The diets used were standard corn-soybean meal diets obtained from a local feed mill. Feed and water were provided ad libitum during the entire experiment. The diets were analyzed for their fluoride content, which was found to vary with the batch of feed mixed and ranged from 2 to 10 ppm during the study. When the pullets reached 20 weeks of age, they were transferred to individual cages in one of two laying batteries, each holding 60 birds.
1 Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the US Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable.
53
Pullets that did not come into production during the first 3 weeks in cages were replaced with similarly treated birds from the floor pens. The hens in one battery, half of which came from each of the two floor pens, received distilled water containing 100 ppm fluoride. The other battery of hens, half of which came from each of the two floor pens, received only tap water during the remainder of the study. Four experimental groups of laying hens were therefore established: one group of birds served as controls (C-C) and had received no supplemental fluoride; another group of laying hens received fluoride during both the growing and laying period (F-F); the remaining two groups of birds received fluoride only during one of the two periods, either during the growing (F-C) or the laying (C-F) period. This experimental design has been described in previous work (Merkley, 1981). The pullets were maintained under conventional cage housing conditions with a lighting schedule of 15 hr per day in a windowless room. In the first trial the hens were force molted by feed and water restriction at 13 months of age, before being inseminated at 15 months of age. Hens in the second trial were inseminated at 11 months of age. In Trial 1 no SCWL males were available, and broiler breeder roosters were obtained from several sources. They were placed in individual cages and provided the same commercial laying diet given the pullets and tap water ad libitum. After a brief adjustment period in the new environment, they served as the semen source. In Trial 2 DeKalb SCWL cockerels were obtained at 1 day old and wing banded. They were divided into two floor pens. One pen of birds served as control cockerels and received tap water. The other pen of cockerels was treated with fluoride in the same manner as the pullets. Two weeks before starting semen collection in Trial 2, 30 males from each group were individually caged in modified laying batteries to allow increased head room as were the broiler breeder cockerels in Trial 1. The cockerels were 8 months old when the pullets were inseminated in Trial 2 at 11 months of age. In both trials pooled semen was collected and diluted 1:1 with the Beltsville Poultry Semen Extender (Sexton, 1977). The last insemination of Trial 1 necessitated a 1:3 dilution because of a reduced semen yield that particular day. The hens were inseminated with
54
MERKLEY AND SEXTON
.05 ml of diluted semen on three separate days. In both trials the hens were inseminated 3 and 11 days after the initial insemination. Eggs were collected daily starting 24 hr after the initial insemination in both trials. The eggs were stored at 13 C (55 F) with a relative humidity of 60 to 70%. Eggs were stored no longer than 4 days prior to incubation. All eggs determined to be infertile or fertile dead on day seven of incubation were broken out and any eggs showing signs of embryo growth were scored as early dead. The presence of blood was the major criterion measured. The percent true fertility is expressed as the number of fertile eggs plus early dead embryos divided by the total number of eggs set. The percent hatchability is expressed as the total number of chicks produced from fertile eggs transferred on day 19 of incubation. The range of percentages did not warrant any transformation of the data, and straight percentages were used in the analysis of variance and Duncan's multiple range test (Snedecor and Cochran, 1968) in both trials.
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There was no statistically significant difference in the percentage of egg production among the four experimental groups of hens prior to the initial insemination in Trial 1 (Table 1). During the 1 month period in which eggs were collected for incubation, the rate of production decreased. Since all groups showed a similar decrease in production, there were no significant differences in the production rates among the
TH
H
RESULTS AND DISCUSSION
There was a difference in the number of hens in each experimental group in Trial 1 (Table 1). The fewer hens used in the F-F group can be attributed to several culling criteria unrelated to the experimental treatment. One hen failed to lay a fertile egg and was eliminated, since at each insemination a hard shelled egg had been present in the oviduct. Another hen laid only eggs with deformed shells, and this appeared to affect hatchability. No inference can be drawn concerning the influence of fluoride on the number of hens suitable as experimental subjects in this trial. Among the hens that remained in the floor pens, there appeared to be no differences in their livability or production ability due to fluoride intake. In previous work no significant effects were found on egg production or egg quality in fluoride treated hens (Guenter, 1979; Merkley, 1981).
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FLUORIDE FERTILITY STUDY
experimental groups during the period in which eggs were collected for incubation. This decrease probably resulted from handling the birds during insemination to which the birds were unaccustomed; it was observed that the month following the experimental period in which eggs were collected all groups showed a similar increase in egg production. As shown in Table 1, there were no statistically significant differences in fertility, hatchability, and duration of fertility among the experimental groups in Trial 1. The total number of embryos classified as late hatching and pips was extremely low (<.6%). From the more than 2400 chicks hatched during Trial 1, approximately 500 from two hatches were randomly selected and raised to 4 weeks of age using standard broiler feed and tap water. No differences were observed in the 4 week growth of chicks from the four experimental groups. Mortality was very low, and no visible leg problems developed regardless of the parental treatments. A wide range of phenotypes was readily apparent. Straight run broilers would be expected to weigh approximately 800 g at 4 weeks and Leghorns approximately 300 g. The 4-week weights (Table 2) of these chicks were between these extremes. In Trial 2, as had been observed in Trial 1, there was a drop in the egg production during the insemination period. This drop was not as great as that in the first trial which might be accounted for by the use of younger hens in Trial 2. At no time was there a significant difference in egg production between the experimental groups. In the second trial, the four experimental
TABLE 2. Four-week progeny weight from Leghorn hens fed fluoride (Trial 1) Hen treatment
Hatch 2
Hatch 3
Fluoride F-F
507 ± 5.5 1 (106) 2 1 3
457 + 4.4 (141)5
Control C-C
496 + 5.9 (90)1
464 ± 5.1 (116)0
1
Mean and SEM expressed in grams.
2
Number of chicks weighed at 4 weeks.
3
Number of chicks that died from 0 to 4 weeks.
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56
MERKLEY AND SEXTON
groups indicated in-Table 3 were different from those in Table 1 (Trial 1). T h e cockerels used in Trial 2 were from t w o t r e a t m e n t groups. Half had been treated with fluoride and were continuing t o receive fluoride in t h e drinking water at the time of semen collection. T h e o t h e r half of SCWL cockerels served as controls and had received n o fluoride s u p p l e m e n t a t i o n . Since t h e p a t t e r n of fluoride exposure had n o significant effect on t h e hens in Trial 1, these pullets were grouped by t h e t r e a t m e n t t h e y were receiving at the time of insemination. T h e experimental groups used in Trial 2 (Table 3) were designated b y t h e t r e a t m e n t of t h e males and females during their period in t h e cages.
However, this could n o t be avoided and m i g h t be a reason for t h e seemingly low fertility levels experienced. T h e results of this s t u d y should encourage further studies with fluoride s u p p l e m e n t a t i o n with larger n u m b e r s of birds including studies u n d e r commercial conditions.
There were n o differences in t h e weights of t h e pullets and cockerels in t h e four experim e n t a l groups ( F 9 - F d , C9-C<5, F9-C<5, C9-Fd) at t h e t i m e of insemination in trial 2. T h e pullets n o t receiving fluoride h a d an average weight of 1815 g and those receiving fluoride 1811 g. T h e control cockerels averaged 2 2 2 2 g and those receiving fluoride 2 1 9 4 g. It is k n o w n t h a t fluoride at levels t h a t d o n o t affect b o d y weights can change o t h e r physiological parameters, such as ascorbic acid levels in tissues of y o u n g chickens (Yu and Driver, 1 9 7 8 ) .
Cakir, A., T. W. Sullivan, and F. B. Mather, 1978. Alleviation of fluoride toxicity in starting turkeys and chicks with aluminum. Poultry Sci. 57: 498-505. Giesen, A. F., G. R. McDaniel, and T. J. Sexton, 1980. Effect of time of day of artificial insemination and oviposition-insemination interval on the fertility of broiler breeder hens. Poultry Sci. 59: 2544-2549. Guenter, W., 1979. Fluorine toxicity and laying hen performance. Poultry Sci. 58:1063. Kuhl, H. J., Jr., and T. W. Sullivan, 1976. Effect of sodium fluoride and high fluoride fertilizer phosphates on performance of laying chickens and egg shell quality. Poultry Sci. 55:2055. (Abstr.) Merkley, J. W., 1976. Increased bone strength in coop-reared broilers provided fluoridated water. Poultry Sci. 55:1313-1319. Merkley, J. W., 1978. Increased bone strength in caged layers provided fluoride. Vol. VI ( J - l l ) . Proc. XVi World's Poultry Congr., Rio de Janeiro, Brazil. Merkley, J. W., 1981. The effect of sodium fluoride on egg production, egg quality, and bone strength of caged layers. Poultry Sci. 60:771—776. Meyer, W. A., and M. L. Sunde, 1974. Bone breakage as affected by type of housing or an exercise machine for layers. Poultry Sci. 53:878-885. Phillips, P. H„ D. A. Greenwood, C. S. Hobbs, C. F. Huffman, and G. R. Spencer, 1960. The fluoride problem in livestock production. Rep. Committee Anim. Nutr. NAS-NRC Bull. 824, Washington, DC. Rowland, L. O., Jr., and R. H. Harms, 1970. The effect of wire pens, floor pens, and cages on bone characteristics of laying hens. Poultry Sci. 49: 1223-1225. Said, N. W., M. L. Sunde, H. R. Bird, and J. W. Suttie, 1979. Raw rock phosphate as a phosphorus supplement for growing pullets and layers. Poultry Sci. 58:1557-1563. Sexton, T. J., 1977. A new poultry semen extender. I. Effect of extension on the fertility of chicken semen. Poultry Sci. 56:1443—1446. Snedecor, G. W., and W. G. Cochran, 1968. Statistical methods. Iowa State Univ. Press, Ames, IA. Yu, M. H., and C. J. Driver, 1978. The effects of fluoride on the growth of 1-ascorbic acid levels of tissues from the domestic chicken (Gallus domesticus). Fluoride 11:60-67.
T h e c o n c e n t r a t i o n of 100 p p m fluoride in t h e drinking water is considered t o be less t h a n t h e m a x i m u m safe range of 3 0 0 t o 4 0 0 p p m when provided in t h e feed (Phillips et al., 1960). When c o m p a r e d t o t h e control chickens, fluoride s u p p l e m e n t a t i o n at a level (100 p p m ) which significantly increases b o n e strength and percent b o n e ash (Merkley, 1981) had n o observable effect o n t h e reproductive characteristics of pullets or cockerels. In trial 2 , where b o t h pullets and cockerels were continuously treated from one day of age with sodium fluoride, t h e results did n o t differ from t h a t of control birds. T h e fertility and hatchability results r e p o r t e d in this trial were lower t h a n e x p e c t e d . T h e percent hatchability in all eggs transferred was lower in Trial 2 t h a n in Trial 1. This reduced hatchability was unrelated t o t h e e x p e r i m e n t a l t r e a t m e n t s and m a y have been due t o difficulties experienced in maintaining p r o p e r h u m i d i t y in t h e incubators. F o r e x a m p l e , there was a high percentage of pips observed in all four g r o u p s : 15.6, 1 2 . 3 , 10.3, and 12.8 for t h e F9-F
ACKNOWLEDGMENT T h e a u t h o r s wish t o express their appreciation to D . M. Gavelek, S.Wildermuth, and V. W. S m o o t for their skilled technical assistance in t h e artificial insemination of t h e experimental birds.
REFERENCES