- Email: [email protected]
Inability to Demonstrate an Effect of Eggshell #49 on Shell Quality in Older Laying Hens
(31998 Applied Poulq Science, Inr
INABILITY TO DEMONSTRATE AN EFFECT OF EGGSHELL #49 ON SHELL QUALITY IN OLDER LAYING HENS
Primarv Audience:
Egg Producers.
Nutritionists. Veterinarians
Inc.) [4] replaced either 20 or 40% of respecDESCRIPTION OF PROBLEM tive inorganic trace minerals in test diets. Defects in shell quality cause significant losses to the commercial egg industry. Washburn [l]estimated from several sources that between 6 and 7% of all eggs laid are downgraded or lost due to shell cracks or breakage. Such problems generally result from formation of a weak eggshell, rough handling of the egg after it is laid, or a combination of both. Occasionally products hypothesized to improve eggshell quality are introduced to the market [2]. Klecker ef al. [3] reported improved shell strength when zinc and manganese proteinates from Eggshell #49 (Alltech, 1
To whom correspondence should be addressed
Manufacturer's recommendations for the use of this product do not involve substituting for existing trace minerals, but rather the addition of 1kg or 1.5 kg/ton of the product for laying hens younger or older than 65 wk of age, respectively. These levels of dietary supplementation would provide either 8 or 12 ppm Mn, 6 or 8 ppm Zn, and 0.7 or 1.0 ppm Cu for younger and older hens, respectively. No adjustment is suggested to account for differing levels of these minerals in existing diets. The NRC [5] requirements for laying hens consuming 100 g feedlday for manganese and
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
NICK DALE' n e University of Georgia, Poultry Science Department, Athens, GA 30602 Phone: (706) 542-9151 FAX: (706)542-8383 Email: [email protected] CHARLES F. STRONG, JR. Cal-MaineFooa3, P.O. Box 1377, Gainesville, GA 30503
EGGSHELL #49 AND SHELL QUALITY
zinc are 20 and 35 ppm, respectively. A requirement is not listed for copper. However, commercial manuals usually recommend much higher levels of these trace minerals [6]. The importance of manganese in maintaining eggshell quality has been recognized for at least 60 yr. Lyons and Insko [Ademonstrated that the poor shell quality associated with 7 ppm manganese was largely overcome in diets containing 57 ppm. Gutowska and Parkhurst [8] subsequently confirmed greater eggshell strength with 65 ppm manganese than with 20 ppm, but felt that the lower figure was adequate to provide acceptable eggshell quality. Couch et al. [9] found that a level of manganese of between 41 and 71 ppm was adequate to provide optimal shell quality, fertility, and hatchability, while Cox and Balloun [lo] reported that not more than 20 ppm manganese was adequate for egg production and satisfactory shell quality. More recently, Ochrimenko et al. [ l l ] found that a level of manganese not greater than 50 ppm sustained optimum shell quality, a finding supported by Karunajeewa and Tham [ 121, who could document no improvement in eggshell quality when manganese levels were increased from 74 to 141ppm. The relatively poor absorption of manganese may be a cause of the variation noted in the studies cited above. Nevertheless, it is reasonable to conclude that 50 ppm dietary manganese should provide an adequate margin of safety to ensure optimal eggshell quality. The importance of zinc in the maintenance of proper eggshell quality has recently been confirmed by Zavodsky et al. [13]. Since zinc is an essential component of the enzyme carbonic anhydrase, which is active in bone calcificationand eggshell formation,zinc deficiency would be expected to have a negative impact on eggshell quality. W o additional reports confirm that the zinc requirement for eggshell quality under most conditions is not greater than 50 ppm [14, 151. Research from Australia [16, 171 reported an increased number of eggs with shell defects when hens were provided saline drinking water. The decrease in shell quality seems to have been associated with a reduction in concentrations of calciumbinding protein and carbonic anhydrase activity. Dietary supplementation with 100 ppm or more of zinc from either zinc sulfate, zinc methionine, or zinc EDTA significantly im-
proved shell quality under these particular conditions. At the request of an integrated egg producer, a study was undertaken at The University of Georgia to evaluate the effect of Eggshell #49 on shell quality, focusing on hens that consistently produced eggs with a specific gravity below 1.080. This figure is frequently considered as an arbitrary dividing point between satisfactory ( > 1.080) and less than optimal ( e1.080) shell quality. Specific gravity has been demonstrated to correlate closely with the commercial grade of eggs processed under industry conditions [18].
MATERIALS AND METHODS A sample of Eggshell #49 provided by the cooperating integrator was tested for trace mineral composition [19] to confirm the cornposition of the specific batch of product. No attempt was made to confirm the proteinate status of these minerals. EXPERIMENT 1(PRELIMINARY TEST) A limited preliminary study was conducted to gauge the degree of response of eggshell quality to the product so as to provide insight for designing a more sensitive subsequent study. Wenty-four hens (Hy-LineW-36, 80 wk of age, unmolted) were placed in individual laying cages 10" x 1 6 (25 x 40 cm) and provided the standard University of Georgia laying diet ad libitum for 10 days. This diet (Table 1) was the control feed in Experiments 1and 2. During a 10-daypre-test period, all eggs were collected each day at 400 p.m., marked with the number of the individual hen, and tested for specific gravity. On Day 11, hens were separated into two groups of 12 hens such that the mean specific gravity of eggs produced by both groups was approximately equal. One set of hens continued to receive the control diet, while the remainder were fed the same diet supplemented with 1.5 kg/ton of Eggshell #49. Following an acclimation period of 8 days, eggs from each hen were evaluated for specific gravity on a daily basis for the 1Cday test period. EXPERIMENT 2 Had Experiment 1 indicated a positive effect of the product on eggshell quality, graded levels of supplementation would have been tested in the subsequent study. However,
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
220
Researc Report DALE and STRONG TABLE 1. Composition of basal ration (University of
221
RESULTS AND DISCUSSION
as will be noted in the Results and Discussion section, no such benefit was observed. Thus, in addition to the two treatments used in the preliminary study, a third treatment was included to examine a possible effect of removing the product from the feed of birds that had received it for a period of 1month. Ninety SCWL hens (Hy-Line W-77, 110 wk of age, molted once) were divided into nine groups of 10 hens each. live hens were placed in each cage (dimensions described above). For 2 wk all hens received the standard University of Georgia cage layer ration. During " the final 8 davs of this Deriod.
Laboratory analysis of the sample of Eggshell #49 supplied by the cooperating integrator met and surpassed the label claim for trace minerals. The product label guaranteed a zinc content of 0.75%, manganese of 0.45%, and copper of 0.10%. Laboratory analysis found 0.89% zinc, 0.55% manganese, and 0.13% copper. Confirmatory analysis was for total mineral content and did not differentiate between organic and inorganic forms. Thus, these data cannot be generalized to apply to all trace mineral proteinates but apply only to this specific product. EXPERIMENT 1(PRELIMINARY TEST) A limited-scale preliminary study was conducted to gauge the magnitude of any improvement in eggshell quality associated with supplementation with the test product. During the 2-wk experimental period, control hens laid a total of 92 e a s and those receiving
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
egg specific gravity was determined daily on a group basis. Based on this data, three groups of 10 hens were assigned to each of the three treatments such that the initial average specific gravity of eggs from each treatment was equal. Treatment 1 served as a control, using the unsupplemented UGA layer diet throughout the experimental period. Hens in Treatment 2 received the control feed supplemented with 1.5 kg/ton of Eggshell #49. Treatment 3 was the same as Treatment 2 during the 1-wk acclimation period and for the initial 3 wk of the test period. At that point, Eggshell #49 was removed from the feed of Treatment 3 and the unsupplemented control diet was fed for the duration of the experiment. Following the acclimation period, the specific gravity of all eggs laid during the previous 24 hr was determined each afternoon at 4:OO p.m. This procedure was followed for the next 5 wk. After the experiment had progressed 3 wk, hens in Treatment 3 were provided the control diet unsupplemented with Eggshell #49. The supplement was withdrawn at this point to determine whether any change in eggshell quality, as measured by specific gravity, could be documented following a sudden removal of the test product from the feed of hens that had become accustomed to it for a period of 1month (1 wk acclimation period plus 3 wk on test).
JAPR EGGSHELL #49 AND SHELL QUALITY
222
P-
Eggs
PERIOD (Days 1-10)
EXPERIMENTAL PERIOD (Days 19-33)
s.G.~.Ls.D.~
#E
w
S.G.2S.D.
Control
71
1.07550.006
92
1.07520.006
Eggshell #49
70
1.076+0.007
89
1.075 20.007
EXPERIMENT 2 Results of the second study are presented in Table 3. During the 5-wk test period, egg production was comparable to what would normally be expected from hens of this age. As the number of hens included in this study was too small to permit a meaningful comparison of egg production, only total number of eggs laid per treatment is included to confirm the active laying status of the flock. Approximately 700 eggs were evaluated for specific gravity in each of the three treatments. Despite this large number of eggs, no effect of Eggshell #49 on specific gravity could be demonstrated between the control and standard Eggshell #49 treatments (Treatment 1
vs. Treatment 2). It will be noted that a slight decrease in specific gravity occurred in both treatments over the course of the experimental period as compared to that registered during the pre-test period. A decline in eggshell quality is consistent with increased flock age. It had been hypothesized that the removal of Eggshell #49 from the feed of birds accustomed to receiving this supplement might provoke a decrease in specific gravity. In fact, the only significant difference in SG observed in this study occurred during the first week after removal of the supplement from the feed of buds in Treatment 3. The specific gravity of eggs from this treatment was significantly lower than that of birds continuing to receive Eggshell #49. However, as the specific gravity of eggs had not increased due to previous feeding of Eggshell #49, this observation is of questionable practical significance. By the second week after removal of the product, no
TABLE 3. Effect of Eggshell X49 on specific gravity (Experiment 2)
EGGSHELL #49a
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
Eggshell #49 laid 89 eggs. As noted in Table 2, no effect of Eggshell #49 could be demonstrated on the specific gravity of eggs laid during this time.
Research Report DALE and STRONG
223 meal [5]. It is thus possible that the effect of the test product on eggshell quality may depend on the ingredients employed in the diet. Similarly, the source of inorganic zinc in the work of Klecker [3] may not have been as available as the zinc sulfate used in the present study. In the 1950s, Edwards [22] demonstrated a difference in the availability to chicks of zinc from various compounds and ores. The lack of response in eggshell quality to zinc and manganese supplementation in the present experiment may have occurred because the margin of safety for these minerals in the test diets was such that the relatively modest additions provided by Eggshell #49 could not have a meaningful impact. Unless special circumstances can be documented, such as those reported by Moreng et ai. [16] or Balnave and Zhang [ l q , the benefit of further supplementation with zinc or manganese in organic or inorganic form has yet to be demonstrated. It is possible that in laying hen diets supplemented with the enzyme phytase, the need for zinc and possibly manganese supplementation could be sharply reduced. Thiel and Weigand [23] reported increased zinc availability when phytase was added to chick diets. Whether long-term feeding of the test product might provide benefits in shell quality was not addressed in these studies. However, it would appear that Eggshell #49 does not improve shell strength during short-term application such as treatment of a flock experiencing a higher than expected incidence of breakage.
CONCLUSIONS ANDAPPLICATIONS 1. Eggshell #49 is marketed as a means of improving shell quality. 2. In studies with laying hens of 80 wk of age (unmolted) and 110 wk of age (molted once), no improvement in shell quality as measured by specific gravity was associated with use of this dietary supplement.
REFERENCES AND NOTES 1. Washburn, K.W., 1982. Incidence, cause, and prevention of eggshell breakage in commercial production. Poultry Sci. 61:2005-2012. 2. Lalshaw, J.D. and K.A. Turner, 1991. Failure of two feed additives (Shell-developer and Ethical) to improve eggshell quality. Poultry Sci. 70593-599. 3. Klecker, D., L. Zemar, V. Siske, and J. Gomez Basauri, 1997. Influence of trace mineral proteinate su plernentation on eggshell quality. Poultry Sci. 76t)Suppl):131 (Abs).
4. Eggshell #49 is a mineral supplement for layers
Inc., Nicholasville,KY. The roduct Eas%:%%%roteinates;Alltech, zinc, 0.45% manganese, and 0.10dcopper calcium carbonate, calcium phosphate,
anfyeast culture constitute the remainder of the product.
5. National Research Council, 1994. Nutrient Requirements of Poultry. 9th Rev. Edition. Natl. Acad. Sci., Washington, DC. 6. Hy-Line W-36 Management Guide (1998-1999), Hy-Line Intl., West Des Moines, IA, recommends addi-
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
significant differences in specific gravity could be demonstrated. While studies reported herein demonstrated no benefit of Eggshell #49 on specific gravity, these results are not necessarily at variance with those of Klecker et al. [3]. In that study, 60 ppm Mn and 50 ppm Zn were included in test diets. In the present study, levels of the test material were supplementedto the standard University of Georgia layer ration, which already included a wide margin of safety for trace minerals (93 ppm manganese and 75 ppm zinc from premix, in addition to calculated amounts of 12 ppm manganese and 20 ppm zinc present in other ingredients). It can be postulated that feeds used in the present study were already so well fortified with trace minerals that no additional benefit could be reasonably expected from a product based on these nutrients, whether in organic or inorganic form. The report of Klecker et al. [3] did not list the ingredients used in their test rations. As the study was conducted in eastern Europe, ingredient composition may well have been different from the corn:soy ration employed in the current study. Different ingredients contain varying amounts of phytate. O’Dell and Savage [u)]demonstrated some 40 yr ago the deleterious effect of phytate on zinc absorption. In a subsequent study Lease et al. [21] demonstrated a reduced availability of zinc in a sesame meal ration compared to a diet containing soy, sesame meal being known to have a much higher level of phytate than soybean
224
EGGSHELL #49 AND SHELL QUALITY
tion of 66 p m manganese and 66 ppm zinc. DeKalb XL Pullet and %yer Management Guide (1995), DeKalb Poultry Research, DeKalb, IL, recommends addition of 70 ppm manganese and 50 ppm zinc. In both cases, these are in addition to levels present in other ingredients.
15. McCormick, C.C., A.H. Abdelsamei, and K. Keshavan, 1985. Energy restriction and zinc supplementation: Effect on e production and egg uality. Pa es 33-39 in: Proc. l& Cornell Nutr. Conf.,lthaca,
d.
16. Moreng, RE, D. Balnave, and D. Zhang, 1992. Dietaryzinc methionine effect on epshell quality of hens drinkingsaline water. Poultry Sci. 1.1163-1167.
8. Gutowska, M.S. and R Parkhursl, 1942. Studies in mineral nutrition of laying hens. I. The manganese requirement. Poultry Sci. 21:277-287.
17. Balnave, D. and D. Zhang, 1993. Responses of laying hens on saline drinkingwater to dietary supplementation with various zinc compounds. PoultIy Sct. 72:603606.
9. Couch, J.R, LE James,and RM. Sherwood, 1947. The effect of different levels of manganese and different amounts of vitamin D in the diet of hens and pullets. Poultry Sci. 2630-37.
18. Slrong, Charles F., Jr., 1989. Relationship between several measures of shell quality and egg breakage in a commercial processing plant. Poultry Sci. 68:173&1733.
10. Cox, A.C. and S.L Balloun, 1969. Manganese reuirements of la ‘ng hens as related to diet calcium. joultry Sci. 48:74C747.
19. Determined by I.C.P., Thermo Jarrell Ash Co., Franklin, MA.
11. Ochrimenko, C., A. Lemser, G. Richter, U. Krause, and K. Bonska, 1993. Influence of manganese content with varying calcium and mineral supply in layer diets on eggshell quality and the bone mineralization of hens. Arch. h i m . Nutr. 4225-3s. 12. Karunqjeewa, H. and S.H. T h a w 1987.The effect of rice pollard and manganese levels in the diet on egg wei ht shell quality, and performance of cross-bred layers. J! Sii. Food Agric. 41:141-152. 13. Zavodsky, G., D. Klecker, and M. Voda, 1992. Effectsof nutrition on eggshell qualitywith zinc oxide and calcium carbonate as sup lements. Zivocisna-Vyroba (Czech. Republic) 3778.5-A2. 14. Holder, D.P. and D.M. Huntley, 1978. Influence of added manganese, magnesium, zinc, and calcium level of eggshell quality. Poultry Sci. 571629-1634.
20. O’Dell, B. L a n d J. E Savage, 1960.Effect ofph ic acid on zinc availability. Proc. SOC.Exp. Biol. d d . 103304-306. 21. Lease, J.G., B.D. Barnett, EJ. Lease, and D.E Turk, 1960. The biological unavailability to the chick of zinc in a sesame meal ration. J. Nutr. 72:66-71. 22. m a r & H.M., Jr., 1959.The availability to chicks of zinc in various compounds and ores. J. Nutr. 69:30& 308.
23. Thiel, U. and E Weigand, 1992. Influence of dietaIy zinc and microbial phytase supplementation on Zn retention and Zn excretion in broiler chicks. Page 460 in: Proc.World’s Poult Cong , Vol. 3. World’s Poultry Sci. Assn., Amsterdam,%e Netherlands.
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
7. Lyons, M. and W.N. Insko, 1937. Chondrodystrophy in the chick embryo produced by manganese deficiency in the diet of the hen. Kentucky Agric. Exp. Sta. Bull. 371~61-75.
INABILITY TO DEMONSTRATE AN EFFECT OF EGGSHELL #49 ON SHELL QUALITY IN OLDER LAYING HENS
Primarv Audience:
Egg Producers.
Nutritionists. Veterinarians
Inc.) [4] replaced either 20 or 40% of respecDESCRIPTION OF PROBLEM tive inorganic trace minerals in test diets. Defects in shell quality cause significant losses to the commercial egg industry. Washburn [l]estimated from several sources that between 6 and 7% of all eggs laid are downgraded or lost due to shell cracks or breakage. Such problems generally result from formation of a weak eggshell, rough handling of the egg after it is laid, or a combination of both. Occasionally products hypothesized to improve eggshell quality are introduced to the market [2]. Klecker ef al. [3] reported improved shell strength when zinc and manganese proteinates from Eggshell #49 (Alltech, 1
To whom correspondence should be addressed
Manufacturer's recommendations for the use of this product do not involve substituting for existing trace minerals, but rather the addition of 1kg or 1.5 kg/ton of the product for laying hens younger or older than 65 wk of age, respectively. These levels of dietary supplementation would provide either 8 or 12 ppm Mn, 6 or 8 ppm Zn, and 0.7 or 1.0 ppm Cu for younger and older hens, respectively. No adjustment is suggested to account for differing levels of these minerals in existing diets. The NRC [5] requirements for laying hens consuming 100 g feedlday for manganese and
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
NICK DALE' n e University of Georgia, Poultry Science Department, Athens, GA 30602 Phone: (706) 542-9151 FAX: (706)542-8383 Email: [email protected] CHARLES F. STRONG, JR. Cal-MaineFooa3, P.O. Box 1377, Gainesville, GA 30503
EGGSHELL #49 AND SHELL QUALITY
zinc are 20 and 35 ppm, respectively. A requirement is not listed for copper. However, commercial manuals usually recommend much higher levels of these trace minerals [6]. The importance of manganese in maintaining eggshell quality has been recognized for at least 60 yr. Lyons and Insko [Ademonstrated that the poor shell quality associated with 7 ppm manganese was largely overcome in diets containing 57 ppm. Gutowska and Parkhurst [8] subsequently confirmed greater eggshell strength with 65 ppm manganese than with 20 ppm, but felt that the lower figure was adequate to provide acceptable eggshell quality. Couch et al. [9] found that a level of manganese of between 41 and 71 ppm was adequate to provide optimal shell quality, fertility, and hatchability, while Cox and Balloun [lo] reported that not more than 20 ppm manganese was adequate for egg production and satisfactory shell quality. More recently, Ochrimenko et al. [ l l ] found that a level of manganese not greater than 50 ppm sustained optimum shell quality, a finding supported by Karunajeewa and Tham [ 121, who could document no improvement in eggshell quality when manganese levels were increased from 74 to 141ppm. The relatively poor absorption of manganese may be a cause of the variation noted in the studies cited above. Nevertheless, it is reasonable to conclude that 50 ppm dietary manganese should provide an adequate margin of safety to ensure optimal eggshell quality. The importance of zinc in the maintenance of proper eggshell quality has recently been confirmed by Zavodsky et al. [13]. Since zinc is an essential component of the enzyme carbonic anhydrase, which is active in bone calcificationand eggshell formation,zinc deficiency would be expected to have a negative impact on eggshell quality. W o additional reports confirm that the zinc requirement for eggshell quality under most conditions is not greater than 50 ppm [14, 151. Research from Australia [16, 171 reported an increased number of eggs with shell defects when hens were provided saline drinking water. The decrease in shell quality seems to have been associated with a reduction in concentrations of calciumbinding protein and carbonic anhydrase activity. Dietary supplementation with 100 ppm or more of zinc from either zinc sulfate, zinc methionine, or zinc EDTA significantly im-
proved shell quality under these particular conditions. At the request of an integrated egg producer, a study was undertaken at The University of Georgia to evaluate the effect of Eggshell #49 on shell quality, focusing on hens that consistently produced eggs with a specific gravity below 1.080. This figure is frequently considered as an arbitrary dividing point between satisfactory ( > 1.080) and less than optimal ( e1.080) shell quality. Specific gravity has been demonstrated to correlate closely with the commercial grade of eggs processed under industry conditions [18].
MATERIALS AND METHODS A sample of Eggshell #49 provided by the cooperating integrator was tested for trace mineral composition [19] to confirm the cornposition of the specific batch of product. No attempt was made to confirm the proteinate status of these minerals. EXPERIMENT 1(PRELIMINARY TEST) A limited preliminary study was conducted to gauge the degree of response of eggshell quality to the product so as to provide insight for designing a more sensitive subsequent study. Wenty-four hens (Hy-LineW-36, 80 wk of age, unmolted) were placed in individual laying cages 10" x 1 6 (25 x 40 cm) and provided the standard University of Georgia laying diet ad libitum for 10 days. This diet (Table 1) was the control feed in Experiments 1and 2. During a 10-daypre-test period, all eggs were collected each day at 400 p.m., marked with the number of the individual hen, and tested for specific gravity. On Day 11, hens were separated into two groups of 12 hens such that the mean specific gravity of eggs produced by both groups was approximately equal. One set of hens continued to receive the control diet, while the remainder were fed the same diet supplemented with 1.5 kg/ton of Eggshell #49. Following an acclimation period of 8 days, eggs from each hen were evaluated for specific gravity on a daily basis for the 1Cday test period. EXPERIMENT 2 Had Experiment 1 indicated a positive effect of the product on eggshell quality, graded levels of supplementation would have been tested in the subsequent study. However,
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
220
Researc Report DALE and STRONG TABLE 1. Composition of basal ration (University of
221
RESULTS AND DISCUSSION
as will be noted in the Results and Discussion section, no such benefit was observed. Thus, in addition to the two treatments used in the preliminary study, a third treatment was included to examine a possible effect of removing the product from the feed of birds that had received it for a period of 1month. Ninety SCWL hens (Hy-Line W-77, 110 wk of age, molted once) were divided into nine groups of 10 hens each. live hens were placed in each cage (dimensions described above). For 2 wk all hens received the standard University of Georgia cage layer ration. During " the final 8 davs of this Deriod.
Laboratory analysis of the sample of Eggshell #49 supplied by the cooperating integrator met and surpassed the label claim for trace minerals. The product label guaranteed a zinc content of 0.75%, manganese of 0.45%, and copper of 0.10%. Laboratory analysis found 0.89% zinc, 0.55% manganese, and 0.13% copper. Confirmatory analysis was for total mineral content and did not differentiate between organic and inorganic forms. Thus, these data cannot be generalized to apply to all trace mineral proteinates but apply only to this specific product. EXPERIMENT 1(PRELIMINARY TEST) A limited-scale preliminary study was conducted to gauge the magnitude of any improvement in eggshell quality associated with supplementation with the test product. During the 2-wk experimental period, control hens laid a total of 92 e a s and those receiving
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
egg specific gravity was determined daily on a group basis. Based on this data, three groups of 10 hens were assigned to each of the three treatments such that the initial average specific gravity of eggs from each treatment was equal. Treatment 1 served as a control, using the unsupplemented UGA layer diet throughout the experimental period. Hens in Treatment 2 received the control feed supplemented with 1.5 kg/ton of Eggshell #49. Treatment 3 was the same as Treatment 2 during the 1-wk acclimation period and for the initial 3 wk of the test period. At that point, Eggshell #49 was removed from the feed of Treatment 3 and the unsupplemented control diet was fed for the duration of the experiment. Following the acclimation period, the specific gravity of all eggs laid during the previous 24 hr was determined each afternoon at 4:OO p.m. This procedure was followed for the next 5 wk. After the experiment had progressed 3 wk, hens in Treatment 3 were provided the control diet unsupplemented with Eggshell #49. The supplement was withdrawn at this point to determine whether any change in eggshell quality, as measured by specific gravity, could be documented following a sudden removal of the test product from the feed of hens that had become accustomed to it for a period of 1month (1 wk acclimation period plus 3 wk on test).
JAPR EGGSHELL #49 AND SHELL QUALITY
222
P-
Eggs
PERIOD (Days 1-10)
EXPERIMENTAL PERIOD (Days 19-33)
s.G.~.Ls.D.~
#E
w
S.G.2S.D.
Control
71
1.07550.006
92
1.07520.006
Eggshell #49
70
1.076+0.007
89
1.075 20.007
EXPERIMENT 2 Results of the second study are presented in Table 3. During the 5-wk test period, egg production was comparable to what would normally be expected from hens of this age. As the number of hens included in this study was too small to permit a meaningful comparison of egg production, only total number of eggs laid per treatment is included to confirm the active laying status of the flock. Approximately 700 eggs were evaluated for specific gravity in each of the three treatments. Despite this large number of eggs, no effect of Eggshell #49 on specific gravity could be demonstrated between the control and standard Eggshell #49 treatments (Treatment 1
vs. Treatment 2). It will be noted that a slight decrease in specific gravity occurred in both treatments over the course of the experimental period as compared to that registered during the pre-test period. A decline in eggshell quality is consistent with increased flock age. It had been hypothesized that the removal of Eggshell #49 from the feed of birds accustomed to receiving this supplement might provoke a decrease in specific gravity. In fact, the only significant difference in SG observed in this study occurred during the first week after removal of the supplement from the feed of buds in Treatment 3. The specific gravity of eggs from this treatment was significantly lower than that of birds continuing to receive Eggshell #49. However, as the specific gravity of eggs had not increased due to previous feeding of Eggshell #49, this observation is of questionable practical significance. By the second week after removal of the product, no
TABLE 3. Effect of Eggshell X49 on specific gravity (Experiment 2)
EGGSHELL #49a
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
Eggshell #49 laid 89 eggs. As noted in Table 2, no effect of Eggshell #49 could be demonstrated on the specific gravity of eggs laid during this time.
Research Report DALE and STRONG
223 meal [5]. It is thus possible that the effect of the test product on eggshell quality may depend on the ingredients employed in the diet. Similarly, the source of inorganic zinc in the work of Klecker [3] may not have been as available as the zinc sulfate used in the present study. In the 1950s, Edwards [22] demonstrated a difference in the availability to chicks of zinc from various compounds and ores. The lack of response in eggshell quality to zinc and manganese supplementation in the present experiment may have occurred because the margin of safety for these minerals in the test diets was such that the relatively modest additions provided by Eggshell #49 could not have a meaningful impact. Unless special circumstances can be documented, such as those reported by Moreng et ai. [16] or Balnave and Zhang [ l q , the benefit of further supplementation with zinc or manganese in organic or inorganic form has yet to be demonstrated. It is possible that in laying hen diets supplemented with the enzyme phytase, the need for zinc and possibly manganese supplementation could be sharply reduced. Thiel and Weigand [23] reported increased zinc availability when phytase was added to chick diets. Whether long-term feeding of the test product might provide benefits in shell quality was not addressed in these studies. However, it would appear that Eggshell #49 does not improve shell strength during short-term application such as treatment of a flock experiencing a higher than expected incidence of breakage.
CONCLUSIONS ANDAPPLICATIONS 1. Eggshell #49 is marketed as a means of improving shell quality. 2. In studies with laying hens of 80 wk of age (unmolted) and 110 wk of age (molted once), no improvement in shell quality as measured by specific gravity was associated with use of this dietary supplement.
REFERENCES AND NOTES 1. Washburn, K.W., 1982. Incidence, cause, and prevention of eggshell breakage in commercial production. Poultry Sci. 61:2005-2012. 2. Lalshaw, J.D. and K.A. Turner, 1991. Failure of two feed additives (Shell-developer and Ethical) to improve eggshell quality. Poultry Sci. 70593-599. 3. Klecker, D., L. Zemar, V. Siske, and J. Gomez Basauri, 1997. Influence of trace mineral proteinate su plernentation on eggshell quality. Poultry Sci. 76t)Suppl):131 (Abs).
4. Eggshell #49 is a mineral supplement for layers
Inc., Nicholasville,KY. The roduct Eas%:%%%roteinates;Alltech, zinc, 0.45% manganese, and 0.10dcopper calcium carbonate, calcium phosphate,
anfyeast culture constitute the remainder of the product.
5. National Research Council, 1994. Nutrient Requirements of Poultry. 9th Rev. Edition. Natl. Acad. Sci., Washington, DC. 6. Hy-Line W-36 Management Guide (1998-1999), Hy-Line Intl., West Des Moines, IA, recommends addi-
Downloaded from http://japr.oxfordjournals.org/ at West Virginia University, Health Science Libraryy on March 10, 2015
significant differences in specific gravity could be demonstrated. While studies reported herein demonstrated no benefit of Eggshell #49 on specific gravity, these results are not necessarily at variance with those of Klecker et al. [3]. In that study, 60 ppm Mn and 50 ppm Zn were included in test diets. In the present study, levels of the test material were supplementedto the standard University of Georgia layer ration, which already included a wide margin of safety for trace minerals (93 ppm manganese and 75 ppm zinc from premix, in addition to calculated amounts of 12 ppm manganese and 20 ppm zinc present in other ingredients). It can be postulated that feeds used in the present study were already so well fortified with trace minerals that no additional benefit could be reasonably expected from a product based on these nutrients, whether in organic or inorganic form. The report of Klecker et al. [3] did not list the ingredients used in their test rations. As the study was conducted in eastern Europe, ingredient composition may well have been different from the corn:soy ration employed in the current study. Different ingredients contain varying amounts of phytate. O’Dell and Savage [u)]demonstrated some 40 yr ago the deleterious effect of phytate on zinc absorption. In a subsequent study Lease et al. [21] demonstrated a reduced availability of zinc in a sesame meal ration compared to a diet containing soy, sesame meal being known to have a much higher level of phytate than soybean
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EGGSHELL #49 AND SHELL QUALITY
tion of 66 p m manganese and 66 ppm zinc. DeKalb XL Pullet and %yer Management Guide (1995), DeKalb Poultry Research, DeKalb, IL, recommends addition of 70 ppm manganese and 50 ppm zinc. In both cases, these are in addition to levels present in other ingredients.
15. McCormick, C.C., A.H. Abdelsamei, and K. Keshavan, 1985. Energy restriction and zinc supplementation: Effect on e production and egg uality. Pa es 33-39 in: Proc. l& Cornell Nutr. Conf.,lthaca,
d.
16. Moreng, RE, D. Balnave, and D. Zhang, 1992. Dietaryzinc methionine effect on epshell quality of hens drinkingsaline water. Poultry Sci. 1.1163-1167.
8. Gutowska, M.S. and R Parkhursl, 1942. Studies in mineral nutrition of laying hens. I. The manganese requirement. Poultry Sci. 21:277-287.
17. Balnave, D. and D. Zhang, 1993. Responses of laying hens on saline drinkingwater to dietary supplementation with various zinc compounds. PoultIy Sct. 72:603606.
9. Couch, J.R, LE James,and RM. Sherwood, 1947. The effect of different levels of manganese and different amounts of vitamin D in the diet of hens and pullets. Poultry Sci. 2630-37.
18. Slrong, Charles F., Jr., 1989. Relationship between several measures of shell quality and egg breakage in a commercial processing plant. Poultry Sci. 68:173&1733.
10. Cox, A.C. and S.L Balloun, 1969. Manganese reuirements of la ‘ng hens as related to diet calcium. joultry Sci. 48:74C747.
19. Determined by I.C.P., Thermo Jarrell Ash Co., Franklin, MA.
11. Ochrimenko, C., A. Lemser, G. Richter, U. Krause, and K. Bonska, 1993. Influence of manganese content with varying calcium and mineral supply in layer diets on eggshell quality and the bone mineralization of hens. Arch. h i m . Nutr. 4225-3s. 12. Karunqjeewa, H. and S.H. T h a w 1987.The effect of rice pollard and manganese levels in the diet on egg wei ht shell quality, and performance of cross-bred layers. J! Sii. Food Agric. 41:141-152. 13. Zavodsky, G., D. Klecker, and M. Voda, 1992. Effectsof nutrition on eggshell qualitywith zinc oxide and calcium carbonate as sup lements. Zivocisna-Vyroba (Czech. Republic) 3778.5-A2. 14. Holder, D.P. and D.M. Huntley, 1978. Influence of added manganese, magnesium, zinc, and calcium level of eggshell quality. Poultry Sci. 571629-1634.
20. O’Dell, B. L a n d J. E Savage, 1960.Effect ofph ic acid on zinc availability. Proc. SOC.Exp. Biol. d d . 103304-306. 21. Lease, J.G., B.D. Barnett, EJ. Lease, and D.E Turk, 1960. The biological unavailability to the chick of zinc in a sesame meal ration. J. Nutr. 72:66-71. 22. m a r & H.M., Jr., 1959.The availability to chicks of zinc in various compounds and ores. J. Nutr. 69:30& 308.
23. Thiel, U. and E Weigand, 1992. Influence of dietaIy zinc and microbial phytase supplementation on Zn retention and Zn excretion in broiler chicks. Page 460 in: Proc.World’s Poult Cong , Vol. 3. World’s Poultry Sci. Assn., Amsterdam,%e Netherlands.
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7. Lyons, M. and W.N. Insko, 1937. Chondrodystrophy in the chick embryo produced by manganese deficiency in the diet of the hen. Kentucky Agric. Exp. Sta. Bull. 371~61-75.