Response of Layer Breeders to Dietary Acetylsalicylic Acid.

PHYSIOLOGY AND REPRODUCTION Response of Layer Breeders to Dietary Acetylsalicylic Acid. 1. Effects on Hen Performance and Eggshell Quality1 CHRISTOPHER D. MCDANIEL,2 JANICE M. BALOG,3 MARISUE FREED, ROBERT G. ELKIN, RODGER H. WELLENREITER,4 and PATRICIA Y. HESTER5 Department of Animal Sciences, Purdue University, West Lafayette, Indiana 47907

1993 Poultry Science 72:1084-1092

eggs. The defective integrity of SS and SL eggs results in many of these eggs falling Hens often lay partially calcified (soft- through the cage floor or being eaten by shelled, SS) or uncalcified (shell-less, SL) the hen (Roland, 1977). As a result, many commercial poultry producers are unaware of the high incidence of SS and SL eggs being laid by their flocks. Pullets lay Received for publication July 2, 1992. Accepted for publication February 4, 1993. a high incidence of SS and SL eggs early in journal Paper Number 13,450 of the Purdue the egg production cycle due to double University Agricultural Experiment Station. ovulations (Hughes and Parker, 1971). 2 Present address: University of Georgia, DepartLikewise, another increase in SS and SL ment of Poultry Science, Athens, GA 30602. 3 Present address: USDA, Agricultural Research egg production occurs during the later Service, Poultry Production and Product Safety Re- phase of the egg production cycle (Roland, search, University of Arkansas, Bio-Mass Research 1977; Wilson et al, 1981). Approximately Bldg., Fayetteville, AR 72701. 3.4 to 5.4% of all eggs laid are either SS or 4 Lilly Research Laboratories, P.O. Box 708, GreenSL (Roland, 1977; Wilson et al, 1981; field, IN 46140. 5 To whom correspondence should be addressed. Linton, 1984). INTRODUCTION

1084

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

ABSTRACT Acetylsalicylic acid (ASA, aspirin) is an inhibitor of prostaglandin (PG) synthesis and an antipyretic drug. Because PG may be involved in the premature oviposition of some soft-shelled (SS) and shell-less (SL) eggs, the objective of the present study was to determine whether dietary ASA, as an inhibitor of PG synthesis, would convert SS and SL eggs to hard-shelled (HS) eggs, thus increasing total salable egg output and improving feed efficiency. White Leghorn layer breeders were fed 0, .025, .05, .10, .20, and .40% ASA for the first 13 mo of egg production. When averaged over 13 mo, hens fed .40% dietary ASA laid fewer HS eggs (P < .002), had poorer feed efficiency (P < .03), had increased mortality (P < .0001), and laid smaller eggs (P < .01). All levels of dietary ASA resulted in significant decreases in specific gravity (P < .0001), shell thickness (P < .0001), shell weight (P < .0001), and percentage shell (P < .0001). During Month 1 of production, mortality was greatly increased for hens fed .20 and .40% ASA as compared with hens receiving 0, .025, .05, or .10% ASA (diet by month interaction, P < .0001). However, during the other 12 mo of production, only hens receiving .40% dietary ASA experienced a slight increase in mortality. Also during Month 1 of production, hens fed .20% ASA laid fewer SL eggs, whereas hens fed .05 and .40% ASA laid more SL eggs than birds receiving the control diet (diet by month interaction, P < .0007). In conclusion, chronic feeding of ASA did not improve egg production or feed efficiency. In addition, long-term feeding of ASA to layer breeders proved to be detrimental with respect to early hen livability and eggshell quality. {Key words: acetylsalicylic acid, aspirin, shell quality, prostaglandins, layer breeders)

ACETYLSALICYUC ACID: PERFORMANCE AND EGGSHELL QUALITY

al, 1982; Dinarello et al, 1988). Because elevated environmental temperatures decrease hen performance (Muiruri and Harrison, 1991), several past studies have explored the antipyretic properties of ASA on egg production (Reid et al, 1964; Thomas et al, 1966; Oluyemi and Adebanjo, 1979). Feeding .05% ASA to White Leghorn hens for 10 mo resulted in a 4 to 6% increase in egg production (Reid et al, 1964). This increase was evident even during months without heat stress. In a study conducted by Thomas et al (1966), .05, .10, and .20% ASA in the diet of White Leghorn laying hens for 32 wk resulted in up to a 6% increase in egg production. Again, this increase in production was seen regardless of environmental temperature. Thomas et al. (1966) noted that laying hens receiving .05% ASA had an increase in shell percentage when compared with hens receiving the control diet. Oluyemi and Adebanjo (1979) noted an increase in shell thickness of eggs from 30-wk-old Rhode Island Red x Barred Plymouth Rock hens fed .15 and .20% ASA diets for 4 mo and also an increase in egg production from 30- and 62-wk-old Rhode Island Red x Barred Plymouth Rock hens fed .05% ASA. The increases in egg production as noted in these previous studies (Reid et al, 1964; Thomas et al, 1966; Oluyemi and Adebanjo, 1979) may have been due to a delay in the PG ovipositional peak, thus allowing SS and SL eggs to become completely calcified as HS eggs. This increased calcification, which would increase shell thickness, could result in an increase in HS egg production. Therefore, the present experiment was designed to determine the effect of feeding increasing dosages of ASA to White Leghorn breeder hens for an entire production cycle (13 mo) on HS, SS, and SL egg production, feed efficiency, shell quality, and egg component weights. MATERIALS AND METHODS Management During the Growing Phase

Housing. One thousand and fifty dayold pullet chicks and 120 cockerels of the DeKalb® strain (XL-Link) of White Leghorn

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

Not only does the poor shell quality of SS and SL eggs affect table egg production, but also when breeder eggs are incubated, those with thin shells do not hatch (Bennett, 1992). It is estimated that poor shell quality results in a loss of 478 million $/yr to the U.S. poultry industry (Roland, 1988). A conversion of the production of SS and SL eggs into hardshelled (HS) eggs could greatly boost revenue for the poultry industry. Approximately 57% of all SS and SL eggs that are laid spend less time in the shell gland or uterus (site of calcium deposition) than HS eggs (Hester et al, 1991). The oviposition of HS eggs (Hertelendy and Biellier, 1978a,b; Olson and Hertelendy, 1981; Olson et al, 1986) as well as SS and SL eggs (Hester et al, 1991) appears to be regulated by prostaglandin (PG). Shimada and Asai (1978) noted an increase in the frequency of contraction of the uterus during the premature oviposition of a SL egg. An injection of PGF2a 2 h prior to normal oviposition resulted in premature expulsion of the egg (Shimada and Asai, 1979). Hargrove and Ottinger (1992) induced oviposition 6 h after ovulation with intravenous injections of combinations of 0, .5, 1, 2, and 3 fig of PGF2a and PGEi or PGF2a and PGE2. An increase in circulating levels of PGFM early in eggshell formation was concomitant with premature oviposition of SS eggs (Hester et al, 1991). Acetylsalicylic acid (ASA), the active ingredient of aspirin, is a potent inhibitor of PG synthesis (Vane, 1971; Flower, 1974). Acetylsalicylic acid inhibits PG H synthase or cyclo-oxygenase, an enzyme that converts arachidonic acid into PG (Vane, 1971; Flower, 1974; Clissold, 1986; Weissmann, 1991). Feeding .05% ASA during the 15th mo of production to aged layer breeders with shell quality problems reduced the incidence of SL eggs (Balog and Hester, 1991). However, in that experiment, there was no increase in HS or SS egg production, but rather a decrease in shell thickness of HS eggs. The authors reasoned that, due to the old age of the hens, the birds may have been unable to mobilize enough calcium to convert the SL eggs into HS or SS eggs. The antipyretic properties of ASA have been investigated extensively (Wilson et

1085

1086

MCDANIEL ET AL.

breeder stock were housed on October 24, 1990. The chicks were reared sex separate in suspended wire pens with 20 cockerels per pen (516 cm2 per cockerel) and 25 pullets per pen (413 cm2 per pullet). The birds were divided equally among three environmentally controlled rooms of the grower unit. Lighting. Chicks received continuous light of 20-lx intensity for the first 2 days of age. Light intensity was lowered to 10 and 2.5 be at 3 and 19 days of age, respectively. Beginning on Day 3, a daily photoperiod of 8 h was maintained until hens were 18 wk of age. Feeding. Feed and water were provided for ad libitum consumption throughout the experiment. The birds were fed a standard starter diet for the first 6 wk, followed by a grower ration from 7 to 12 wk, and a developer feed from 13 to 18 wk of age (Table 1).

Management During the Laying Phase

TABLE 1. Composition of the starter, grower, developer, and layer rations Diet Ingredients and analyses

Starter

Grower

Developer

Layer

IOI

\lo

Ground yellow corn Soybean meal (48% CP) Soybean oil Alfalfa meal (17% CP) Standard midds Dicalcium phosphate Calcium carbonate Oyster shell Salt Vitamin-trace mineral premix 1 L-lysine-HCl Methionine-hydroxy analog Antioxidant 2 Mold inhibitor 3 Sand 4 Calculated analysis ME, kcal/kg CP, % Ca, % Available P, %

64.98 21.26 1.00 1.74

68.31 27.97

66.37 20.46

64.65 12.53

1.85 1.00

10.00 1.50 1.00

20.00 1.30 .90

.35 .25

.35 .23

.08

.05

.06 .10 .05 .40

2,903 17.4 .78 .42

2,832 15.0 .69 .38

2,870 16.3 3.51 .39

.35 .28 .10 .10 .05

2,971 19.7 .86 .48

1.49 5.38 2.74 .45 .35

1 Vitamin-trace mineral premix contained the following per kilogram of mix: vitamin A, 2,645,549 USPU; cholecalciferol, 992,081 ICU; vitamin E, 1,323 IU; riboflavin, 1,764 mg; pantothenic acid, 2,646 mg; niacin, 8,819 mg; choline chloride, 165,347 mg; vitamin Bj2,2 mg; menadione sodium bisulfite complex, 1,411 mg; iodine, 401 mg; manganese, 33,069 mg; copper, 1,466 mg; iron, 13,228 mg; zinc, 24,251 mg; selenium, 86 mg. 2 Dry Polyanox®, Flavor Corp. of America, Northbrook, IL 60062. 3Dry Mold Chek®, Plus Agrimerica, Inc., Northbrook, IL 60062. 4 Amount of sand was decreased to accommodate for each acetylsalicylic acid diet supplement.

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

Housing. At 17 wk of age, birds were transferred to each of five environmentally controlled caged-layer rooms. The middle two of four rows (45 cages per row) on both sides of each room were used to house the hens, thereby utilizing 180 cages per room. The birds were divided into treatment replicate groups of 15 hens, so that each cage row consisted of three dietary treatments; thus, all six dietary treatments were represented on each side of a room. Treatments were assigned randomly to each side of a room, so that there were two replicates of each treatment per room. Five pullets were selected randomly from each room of the grower facility for each treatment group in the layer unit. Roosters, which were used for artificial insemination in a hatchability

ACETYLSALICYUC ACID: PERFORMANCE AND EGGSHELL QUALITY

ing the weight of the shell and yolk from the whole egg (Fletcher et ah, 1981). Percentage shell was calculated by dividing shell weight by initial egg weight and multiplying the quotient by 100. Shell thickness, which included the shell membrane thickness, was measured with a caliper at eight representative areas of each shell and then averaged. Measurements of thickness included two at the large end, two at the small end, and four at the equator of each egg. Statistical Analysis Mortality, feed per hen per day, feed per dozen eggs, hen-day egg production, specific gravity, shell thickness, egg weight, albumen weight, and shell weight data were subjected to an analysis of variance using a randomized complete block design and a split plot with respect to months of lay. The five rooms in the layer facility served as blocks. Blocks, dietary treatments, and months were fixed effects, and replicates were random (Steel and Torrie, 1980). Variances were subjected to the SAS® software univariate procedure to determine normality (SAS Institute, 1991). To obtain homogenous variances, percentage data were transformed to arc sine, whereas logarithmic transformation was used for weight data (Steel and Torrie, 1980). However, statistical patterns were similar for both transformed and untransformed results. Therefore for ease of interpretation, only untransformed results will be presented. Newman-Keuls' sequential range test was used to partition differences among means (Steel and Torrie, 1980). RESULTS Hens receiving .400% dietary ASA for 13 mo produced fewer HS eggs than birds receiving the control diet or the lower dietary levels of ASA (Table 2, P < .002). A typical age-related decline in HS egg production was observed in control and ASA dietary treatment groups (data not shown, P < .0001). Dietary ASA did not affect the production of SS eggs. Hen-day production of SL eggs differed among treatments only during the 1st, 10th, and 11th mo of production (Table 3, diet by month interaction, P < .0007, SEM = .3).

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

study (McDaniel et ah, 1993a), were caged on the bottom two rows of each room in the first 12 cages. The roosters were transferred so that four randomly selected roosters from each room of the grower unit were transferred to each room of the layer unit. Lighting. At 17 wk of age, light intensity was increased to 5 be followed by an increase to 10 lx at 18 wk of age where it remained until termination of the experiment. At 18 wk of age, the hours of light were increased 30 min/wk for 4 wk. At 22 wk of age, the hours of light were increased by 15 min/wk, for 15 wk. The hours of light were stepped up each week by alternating the light increases to both ends of the day. A 14-h photoperiod was maintained from 37 wk of age until termination of the experiment. Feeding. A standard layer ration was fed from 19 until 22 wk of age (Table 1). At 22 wk of age, the hens received either 0, .025, .050, .100, .200, or .400% of dietary ASA (Table 1). The roosters received a standard rooster ration with no ASA supplementation containing 3,165 kcal ME/kg, 12.36% CP, 1.2% Ca, and .67% available P. Egg Collection. Eggs were collected twice daily at 1030 and 1430 h. Dropping boards were placed under each cage so that SS and SL eggs could be recorded accurately. Boards were scraped clean after collection of a SS or SL egg. Five eggs per replicate were selected at random once every month for the first 13 mo of egg production (from 22 wk of age to 74 wk of age) in order to obtain the following measurements: egg weight, specific gravity, yolk weight, albumen weight, shell weight, and shell thickness. Egg weights were determined both in air and in water, thereby enabling calculation of specific gravity by Archimedes Principle (Voisey and Hunt, 1974). To obtain the weights of individual egg components, egg contents were separated by hand, and yolks were rolled on a damp paper towel to remove excess albumen and chalazae. Shells were rinsed in tap water, followed by deionized water. The eggshells were dried overnight in an oven at 50 C. The shells were removed from the oven, allowed to cool at room temperature for 15 min, and weighed with shell membranes intact. Albumen weight was determined by subtract-

1087

1088

MCDANIEL ET AL. TABLE 2. The effect of dietary acetylsalicylic acid (ASA) on hen-day egg production1 Egg production

ASA

Hardshelled (HS)

Soft-

85.0a 85.1* 85.0' 83.2" 82.5a 79.6b 1.0

1.0 .9 1.3 1.2 1.5 1.5 .2

Shellless (SL)

shelled (SS)

(%)

SS + SL

HS + SS + SL

2.3 2.1 2.9 2.5 3.0 3.3 .3

87.3" 87.2" 87.9* 85.7 ab 85.5 ab 82.9b .9

- (% egg production)

0 .025 .050 .100 .200 .400 SEM

1.3 1.2 1.6 1.3 1.5 1.8 .2

Hens receiving .200% ASA during the 1st mo of production laid fewer SL eggs than hens fed the control diet. Also during the 1st mo of production, hens fed .050 and .400% ASA produced more SL eggs when compared with the controls. Birds consuming .400% ASA during the 10th mo of production laid more SL eggs than birds fed .100% ASA with no differences in SL egg production among all other treatments. During Month 11 of production, hens receiving .400% ASA laid more SL eggs than all other diets. Total SS plus SL egg production did not differ among diets (Table 2), although SS and SL egg production increased with age (data not shown, P < .0001). Total hen-day egg production (HS + SS + SL) was reduced for hens fed

.400% ASA when compared with the controls (Table 2, P < .005). When averaged over 13 mo of production, feed consumption was decreased for hens given .400% ASA compared with hens fed the .050% ASA diet (Table 4, P < .02). Feed consumption increased with age (data not shown, P < .0001). When averaged over 13 mo of production, hens consuming .400% ASA had poorer feed efficiency (feed consumed per dozen eggs) when compared with the controls (Table 4, P < .03). As the hens aged, feed efficiency became poorer (data not shown, P < .0001). A 13-mo average indicated that hens fed .400% ASA had significantly higher mortality than controls (Table 4, P <

TABLE 3. The monthly effect of dietary acetylsalicylic acid (ASA) on hen-day production of shell-less eggs Month of production ASA

1

2

3

4

5

3.3 cd 2.9 de 4.9" 3.8 bc 2.4'

1.7 1.8 2.1 1.7 2.0 2.2

1.5 1.0 1.0 1.4 1.2 1.1

.9 .8 1.3 1.0 1.1 1.5

.8 1.0 .7 1.0 .7 .8

a

7

8

9

10

11

12

13

.9 1.1 1.2 1.0 1.4 1.5

1.3ab 1.3ab 1.7ab 1.0b 1.8ab 2.1*

1.0b .8 b 1.7b 1.0b 1.6b 2.6a

1.1 1.4 1.4 .7 1.5 1.7

1.6 1.1 1.8 1.3 1.9 1.5

- ( % egg production)

(%) 0 .025 .050 .100 .200 .400

6

4 . 2 ab

1.2 .7 .7 .9 .9 1.1

.7 .8 1.4 1.3 1.7 1.4

.9 .8 1.2 1.1 1.5 1.3

-*Means for diet by month interaction (P < .0007) in the same column with no common superscripts differ significantly (P < .05). SEM = .3.

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

ab ' Means for main effect of diet in the same column with no common superscripts differ significantly (P < .05). Values represent the replicate means of the 1st through the 13th mo of production of 10 replicates of 15 hens each per diet per month (n = 130).

ACETYLSAUCYLIC ACID: PERFORMANCE AND EGGSHELL QUALITY

1089

TABLE 4. The effect of dietary acetylsalicylic acid (ASA) on feed efficiency and mortality1 ASA

Feed per hen per day

Feed per dozen eggs

Mortality

(%)

(g) 101.9»b 102.0"'' 102.8" 102.0* 99.6* 98.8b .9

(kg) 1.45b 1.45b 1.46ab 1.48ab 1.46ab 1.51a .01

(%)

0 .025 .050 .100 .200 .400 SEM

.3b .2b

.4b .l b .6" 1.8» .2

.0001). A diet by month interaction was due to more hens dying during Month 1 in the .200 (5.3%) and .400% (14.0%) ASA groups than in the other treatment groups (data not shown, P < .0001, SEM = .5). Lower levels of ASA, 0 (0%), .025 (0%), .050 (1.3%), and .100% (0%), did not affect mortality. Eggshell quality as determined by specific gravity was significantly lowered by all levels of dietary ASA, but the greatest decrease occurred in hens fed .400% ASA (Table 5, P < .0001). Shell thickness was also adversely affected by all levels of dietary ASA (Table 5, P < .0001). Greatest decreases of shell thickness occurred in hens fed ASA levels of .200% or greater. A diet by month interaction for specific gravity (P < .04) and shell thickness (data not shown, P < .03) was

observed, but during no month did an ASA diet result in a specific gravity or shell thickness greater than that produced by hens fed the control diet. The diet by month interaction was due to no differences in specific gravity or shell thickness among treatments during Weeks 6, 18, 30, 34, and 38 of production; but in all of the other weeks, reductions in specific gravity and shell thickness were most apparent in hens fed .200 and .400% ASA. All levels of ASA decreased the amount of shell relative to whole egg (Table 5, P < .0001), again with .400% ASA being the most detrimental. A diet by month interaction (data not shown, P < .05) for percentage shell was similar to that described for specific gravity and shell thickness in that some weeks of production showed no differences among treatments (4, 6, 18, 30,

TABLE 5. The effect of dietary acetylsalicylic acid (ASA) on shell quality1 ASA

Specific gravity

Shell thickness

Percentage shell

(%) 0 .025 .050 .100 .200 .400 SEM

(mm) .367* .358b .360b .361b .353= .349= .001

(%)

1.0834a 1.0817b 1.0819b 1.0820b 1.0812bc 1.0805= .0003

8.92* 8.69b 8.70b 8.69b 8.58bc 8.49= .03

a -=Means for main effect of diet in the same column with no common superscripts differ significantly (P < .05). Values represent the replicate means of the 1st through the 13th mo of production of 10 replicates of 15 hens each per diet per month (n = 130).

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

a b - Means for main effect of diet in the same column with no common superscripts differ significantly (P < .05). Values represent the replicate means of the 1st through the 13th mo of production of 10 replicates of 15 hens each per diet per month (n = 130).

1090

MCDANIEL ET AL.

DISCUSSION Although previous work has shown that feeding .050, .100, and .200% ASA

increased HS egg production (Reid et ah, 1964; Thomas et ah, 1966; Oluyemi and Adebanjo, 1979), no increase in HS egg production was found in this study using the same levels of dietary ASA. Balog and Hester (1991) noted a decrease in SL egg production during the first 2 wk of feeding .05% dietary ASA to a group of aged breeder hens laying a high incidence of SS and SL eggs. In the present study, during the 1st mo of lay, hens were also laying a high incidence of SL eggs. Results of Balog and Hester (1991) are comparable to the observed decrease in SL egg production during the 1st mo in the present study in hens administered .200% ASA, but not with the hens fed the other levels of ASA (Table 3). Also, it is noteworthy that hens fed .400% ASA in the present study laid fewer total eggs (HS + SS + SL) when compared with hens fed 0, .025, or .050% ASA (Table 2), suggesting that the highest dosage of ASA was inhibiting ovulation. In contrast to its action in mammals (Hertelendy, 1980), PG, as well as inhibitors of PG, do not block ovulation in avians (Day and Nalbandov, 1977; Samsonovitch and Lague, 1977). Therefore, the reduced ovulation rate in the hens fed .400% ASA of the present study may have been related to reduced feed consumption (Table 4) rather than to an inhibition of PG. As in the present study, Thomas et ah (1966), Oluyemi and Adebanjo (1979), and Balog and Hester (1991) found no differences in daily feed consumption among

TABLE 6. The effect of dietary acetylsalicylic acid (ASA) on egg component weights1 ASA

Egg weight

Yolk weight

58.5' 58.3* 58.8* 58.9a 58.3* 57.4b .3

15.9* 15.9* 16.0* 16.0* 15.8* 15.6b .1

Shell weight

37.3 37.2 37.6 37.6 37.3 37.1 .2

5.21» 5.061* 5.11 b 5.11b 5.00^ 4.86<* .02

(g)

(%) 0 .025 .050 .100 .200 .400 SEM

Albumen weight

a_d Means for main effect of diet in the same column with no common superscripts differ significantly (P < .05). x Values represent the replicate means of the 1st through the 13th mo of production of 10 replicates of 5 eggs each per diet per month for egg and shell weights and 10 replicates of 3 eggs each per diet per month for yolk and albumen weights (n = 130).

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

34, and 42). The remaining weeks in which measurements were taken showed an adverse effect on percentage shell due to ASA, especially with .200 and .400% ASA. In no instance was percentage shell improved when compared with controls by adding ASA to the diet. Specific gravity, shell thickness, and percentage shell showed a typical age related decline in shell quality (data not shown, P < .0001). Hens fed .400% ASA laid smaller eggs (P < .01) when compared with the controls (Table 6). Also, hens fed .400% ASA laid eggs with smaller yolks when compared with the hens fed .100% ASA (P < .02). However, albumen weights were not affected by dietary treatments. The weights of the eggshells from hens fed all levels of dietary ASA were less than those of hens receiving the control diet (P < .0001). Hens consuming .400% ASA laid eggs of lower shell weight throughout the study when compared with controls, but no significant differences were apparent at Weeks 4, 6, and 30 of production (data not shown, diet by month interaction, P < .01). As with specific gravity, shell thickness, and percentage shell, at no time did any level of ASA result in a significant increase in shell weight. As hens aged, the weight of the egg, shell, yolk, and albumen increased (data not shown, P < .0001).

ACETYLSAUCYLIC ACID: PERFORMANCE AND EGGSHELL QUALITY

among breeds, strains, environments, and management may explain in part the discrepancy among studies on the effect of ASA on shell quality. Feed samples were analyzed by HPLC for ASA content, and results indicated that ASA was present in the feed at approximately 100% of the calculated levels (McDaniel et al, 1993b). Therefore, it is doubtful that birds were not receiving the calculated levels of ASA. However, in a companion study, circulating PG levels were not decreased in hens fed .050 or .400% ASA for either 1 wk or 1 mo (Balog et al, 1993). In addition, it is not unreasonable to deduce that the birds fed the higher levels of ASA may have partially acclimated to the drug. For example, during the 1st mo of production, mortality was greatly increased in hens fed .200 and .400% ASA, whereas in subsequent months, mortality was not extremely elevated in these treatment groups. However, hens fed ASA did not totally acclimate to the drug because shell quality was adversely affected throughout the study (Table 5). In conclusion, chronic feeding of ASA did not improve egg production. In addition, long-term feeding of ASA, especially at the higher levels, proved to be detrimental with respect to early breeder hen livability and shell quality. ACKNOWLEDGMENTS

This research was supported by the Value Added Center of the Indiana Office of the Commissioner of Agriculture and by Lilly Research Laboratories, Greenfield, IN 46140. Day-old breeder chicks were kindly donated by DeKalb® Poultry Research, Inc., DeKalb, IL 60115. The vitamin-trace mineral premix was donated by Dawe's Laboratories, Chicago, IL 60646.

REFERENCES Balog, J. M, and P. Y. Hester, 1991. The effect of dietary acetylsalicylic acid on eggshell quality. Poultry Sci. 70:624-630. Balog, J. M., C. D. McDaniel, M. Freed, R. G. Elkin, R. H. Wellenreiter, and P. Y. Hester, 1993. Response of layer breeders to dietary acetylsalicylic acid. 2. Effects on circulating levels of prostaglandin F 2a . Poultry Sci. 72:1093-1099. Bennett, C. D., 1992. The influence of shell thickness on hatchability in commercial broiler breeder flocks. J. Appl. Poult. Res. 1:61-65.

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

birds fed .05, .10, or .15% ASA. However, Thomas et al. (1966) observed an improvement in feed consumed per dozen eggs with .05, .10, and .20% ASA, which was not evident in the present study (Table 4). Even though .200% ASA increased mortality during the 1st mo of production in this study, Oluyemi and Adebanjo (1979) found no increase in mortality with .200% ASA. Upon post-mortem examination, it was revealed that many of the hens fed .200 and .400% ASA died of excessive internal and external bleeding. Lack of blood clotting may have been due to ASA inhibition of PGH2 synthesis (Hanks, 1983). Just as Balog and Hester (1991) found a decrease in specific gravity and shell thickness with .05% ASA given to layer breeders laying a high incidence of SS and SL eggs, a decrease in specific gravity and shell thickness was observed in the present study in hens fed ASA (Table 5). However, Oluyemi and Adebanjo (1979) found an increase in shell thickness of eggs from 30-wk-old hens given .15 and .20% ASA. Thomas et al. (1966) reported an increase in percent shell of hens fed .05% ASA in one experiment. However, in their second experiment, higher levels of ASA (.20 to .80%) decreased percentage shell, whereas .05% ASA was not different from the control diet. The results of the present study are in agreement with the second experiment of Thomas et al. (1966). Apparently, hens given ASA will not produce more shell relative to whole egg. Thomas et al. (1966) and Balog and Hester (1991) reported no differences in egg weight with .05% ASA, but Thomas et al. (1966) reported a reduction in egg weight of hens fed .10, .20, .40, and .80% dietary ASA when compared with hens fed a control diet. As noted earlier, .400% ASA decreased egg weight in the present study (Table 6). In contrast, Oluyemi and Adebanjo (1979) obtained an increase in egg size in hens given .05 and .10% ASA. The results of the present investigation are the first to show that long-term feeding of even low levels of ASA can be detrimental to shell quality (Table 5), which is in contrast to the studies of Reid et al. (1964), Thomas et al. (1966), and Oluyemi and Adebanjo (1979). Differences

1091

1092

MCDANIEL ET AL. domestic hen (Gallus domesticus). Biol. Reprod. 24:496-504. Olson, D. M., K. Shimada, and R. J. Etches, 1986. Prostaglandin concentrations in peripheral plasma and ovarian and uterine plasma and tissue in relation to oviposition in hens. Biol. Reprod. 35:1140-1146. Oluyemi, J. A., and A. Adebanjo, 1979. Measures applied to combat thermal stress in poultry under practical tropical environment. Poultry Sci. 58:767-773. Reid, B. L., A. A. Kurnick, J. M. Thomas, and B. J. Hullet, 1964. Effect of acetyl-salicylic acid and oxytetracycline on the performance of White Leghorn breeders and broiler chicks. Poultry Sci. 43:880-884. Roland, D. A., Sr., 1977. The extent of uncollected eggs due to inadequate shell. Poultry Sci. 56: 1517-1521. Roland, D. A , Sr., 1988. Research Note: Egg shell problems: Estimates of incidence and economic impact. Poultry Sci. 67:1801-1803. Samsonovitch, M., and P. C. Lague, 1977. Effects of prostaglandin Ej, E2 and indomethacin on ovulation in the domestic fowl. Poultry Sci. 56: 1754.(Abstr.) SAS Institute, 1991. SAS® System for Linear Models. 3rd ed. SAS Institute Inc., Cary, NC. Shimada, K., and I. Asai, 1978. Uterine contraction during the ovulatory cycle of the hen. Biol. Reprod. 19:1057-1062. Shimada, K., and I. Asai, 1979. Effects of prostaglandin F2a and indomethacin on uterine contraction in hens. Biol. Reprod. 21:523-527. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. A Biometrical Approach. 2nd ed. McGraw-Hill Book Co., Inc., New York, NY. Thomas, J. M., H. S. Nakaue, and B. L. Reid, 1966. Effect of increasing dietary levels of acetylsalicylic acid on performance and cecal microbial counts of White Leghorn pullets. Poultry Sci. 45:1313-1317. Vane, J. R., 1971. Inhibition of prostaglandin synthesis as a mechanism of action for aspirin-like drugs. Nat. New Biol. 231:232-235. Voisey, P. W., and J. R. Hunt, 1974. Measurements of eggshell strength. J. Texture Stud. 5:135-182. Weissmann, G., 1991. Aspirin. Sci. Am. 264:84-90. Wilson, E. K., P. Y. Hester, F. W. Pierson, and I. Fabijanska, 1981. Production profile and organ weights of White Leghorn hens which lay softshelled and shell-less eggs. Poultry Sci. 60: 2356-2359. Wilson, J. T., R. D. Brown, J. A. Bocchini, Jr., and G. L. Kearns, 1982. Efficacy, disposition, and pharmacodynamics of aspirin, acetaminophen, and choline salicylate in young febrile children. Ther. Drug Monit. 4:147-180.

Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015

Clissold, S. P., 1986. Aspirin and related derivatives of salicylic acid. Drugs 32:8-26. Day, S. L., and A. V. Nalbandov, 1977. Presence of prostaglandin F (PGF) in hen follicles and its physiological role in ovulation and oviposition. Biol. Reprod. 16:486-494. Dinarello, C. A, J. G. Cannon, and S. M. Wolff, 1988. New concepts on the pathogenesis of fever. Rev. Infect. Dis. 10:168-184. Fletcher, D. L., W. M. Britton, A. P. Rahn, and S. I. Savage, 1981. The influence of layer flock age on egg component yields and solids content. Poultry Sci. 60:983-987. Flower, R. J., 1974. Drugs which inhibit prostaglandin biosynthesis. Pharmacol. Rev. 26:33-67. Hanks, G. W., 1983. Nonprescription analgesics: I. Acetylsalicylic acid. Clin. Ther. (Suppl. A)5:l-23. Hargrove, T. L., and M. A. Ottinger, 1992. Induced oviposition of precalcified eggs following prostaglandin administration. Poultry Sci. 71: 548-552. Hertelendy, F., 1980. Prostaglandins in avian endocrinology. Pages 455-479 in: Avian Endocrinology. A. Epple and M. H. Stetson, ed. Academic Press, New York, NY. Hertelendy, F., and H. V. Biellier, 1978a. Evidence for a physiological role of prostaglandins in oviposition by the hen. J. Reprod. Fertil. 53:71-74. Hertelendy, F., and H. V. Biellier, 1978b. Prostaglandin levels in avian blood and reproductive organs. Biol. Reprod. 18:204-211. Hester, P. Y., N. F. Newlon, and P. M. Klingensmith, 1991. Plasma, follicular, and uterine levels of prostaglandins in chickens producing softshelled and shell-less eggs. Poultry Sci. 70: 1585-1593. Hughes, B. L., and J. E. Parker, 1971. Time of oviposition of shell-less eggs. Poultry Sci. 50: 1509-1511. Linton, D. D., 1984. Magnitude of Genetic Influence and Social Environment on Soft-Shelled and Shell-Less Egg Production. M.S. thesis, Purdue University, West Lafayette, IN. McDaniel, C. D., J. M. Balog, M. Freed, R. G. Elkin, R. H. Wellenreiter, T. Kuczek, and P. Y. Hester, 1993a. Response of layer breeders to dietary acetylsalicylic acid. 3. Effects on fertility and hatchability of embryos exposed to control and elevated incubation temperatures. Poultry Sci. 72:1100-1108. McDaniel, C. D., M. Freed, J. M. Balog, R. H. Wellenreiter, P. Y. Hester, and R. G. Elkin, 1993b. Response of layer breeders to dietary acetylsalicylic acid. 4. Egg residue studies. Poultry Sci. 72:1109-1117. Muiruri, H. K., and P. C. Harrison, 1991. Effect of roost temperature on performance of chickens in hot ambient environments. Poultry Sci. 70: 2253-2258. Olson, D. M., and F. Hertelendy, 1981. Plasma levels of 13,14-dihydro-15-keto prostaglandin Via in relation to oviposition and ovulation in the