The Effects of Dietary Acetylsalicylic Acid on Heat Stress Infertility of Broiler Breeder Males

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1 Internatinal Jurnal f Pultry Science 3 (9): , 004 Asian Netwrk fr Scientific Infrmatin, 004 The Effects f Dietary Acetylsalicylic Acid n Heat Stress Infertility f Briler Breeder Males C.D. McDaniel and H.M. Parker Department f Pultry Science, Mississippi State University, Mississippi State, MS 3976, USA cmcdaniel@pultry.msstate.edu Abstract: An attempt was made at imprving fertility f male briler breeders expsed t elevated ambient temperatures. Acetylsalicylic acid (ASA, aspirin) is a ptent antipyretic drug that has been shwn t lwer the bdy temperature f heat stressed chickens. Because deviatin in bdy temperature abve nrmal is negatively crrelated with fertility, the bjective f the present study was t determine if ASA wuld lwer rectal temperature f heat stressed male briler breeders and imprve fertility. Thirty six Arbr Acres rsters were divided equally amng three cntrlled temperature rms and caged individually. Half f the males in each rm were fed.15% ASA, while the ther half f the birds received the cntrl (C) diet. Males were fed the C and ASA diets beginning 1 wk prir t heat stress treatment. After this pretreatment perid, the temperature in all three cntrlled temperature rms was increased t 9 C. Fllwing ne wk at 9 C, rm temperature was increased further t 3 C fr 3 wk. Once every wk f the experiment, 10 hens were inseminated with 50 millin sperm frm either ASA r C fed males. Dietary ASA did nt lwer the bdy temperature f the heat stressed rsters. Males fed ASA cnsumed less feed than males fed the C diet. In general, semen characteristics, such as semen vlume, sperm cncentratin, and percentage f dead sperm prduced, were unaffected by dietary treatment. Hwever, additin f ASA t the heat stressed male's diet resulted in a linear decrease in fertility ver Weeks thrugh 4 f the experiment and a greater reductin in fertility ver days pstinseminatin than that btained fr males receiving the C diet. In viv sperm-egg penetratin was similar whether hens were inseminated with semen frm C r ASA fed males. In cnclusin,.15% ASA in the male's diet des nt decrease bdy temperature when rsters are expsed t elevated ambient temperatures. In additin, 0.15% dietary ASA appears t be detrimental t fertility f heat stressed briler breeder males. Key wrds: Acetylsalicylic acid, heat stress, fertility, briler breeder, bdy temperature Intrductin Bdy temperature f mature briler breeder males increases apprximately ne degree C during expsure t an ambient temperature f 3 C. Cncurrent with this increase in male rectal bdy temperature is a decrease f 4 and 5% in candling fertility and in viv sperm-egg penetratin, respectively. Candling fertility and in viv sperm-egg penetratin have been shwn t be highly crrelated with male rectal bdy temperature (McDaniel et al., 1995b). These crrelatins indicate that it may be pssible t alleviate heat stress infertility f male briler breeders by lwering bdy temperature during elevated envirnmental temperatures. Acetylsalicylic acid (ASA, aspirin) is a well knwn antipyretic drug (Weissmann, 1991). Aspirin inhibits prstaglandin synthesis and "resets the hypthalamic thermstat". It has been demnstrated that feeding ASA t chickens during heat stress lwers bdy temperature. Adams and Rgler (1968) fund that feeding 0.05% ASA t brilers decreased bdy temperature by as much as 0.3 degrees C when birds were expsed t 9 C as cmpared t results btained fr birds fed a cntrl (C ) diet. In 1963, Glick determined that feeding 0.15, 0.30 and 0.60% ASA decreased bdy temperature 0.4, 1., and 0.6 degrees C respectively, when 5 and 56 d ld New Hampshire chicks were heat stressed at 40.6 C. Hutchins et al. (196) fund that feeding 0.5 and 0.5% sdium salicylate, a less ptent antipyretic analg f ASA (Weissmann, 1991), decreased the bdy temperature f chicks expsed t 40.6 C by apprximately.3 degrees C. The crrect dietary level f ASA may als decrease the bdy temperature f heat stressed briler breeders. In additin, it appears that feeding ASA t hens during heat stress cnditins imprves egg quality and egg prductin (Oluyemi and Adebanj, 1979; Reid et al., 1964). Because egg mass has been shwn t be crrelated with packed sperm vlume (Marks, 1978), it is pssible that during heat stress cnditins the ASA mechanism respnsible fr increasing egg quality and egg prductin may als increase sperm quality and sperm prductin. Therefre, the bjectives f the present study were t determine if feeding ASA t heat stressed briler breeder rsters wuld lwer bdy temperature and increase verall fertility. Materials and Methds Husing and Envirnment: Thirty six Arbr Acres 570

2 rsters were caged individually in three cntrlled Renden (1984). temperature rms (1 males/rm). Maximum and minimum temperature in each rm was recrded daily Pled semen characteristics and artificial with a high-lw thermmeter. The birds were maintained inseminatin: On the first d f each wk f the heat stress at 1 C (Maximum = 1±.6 C; Minimum = 18±.6 C) fr 18 perid, semen was cllected frm each male and wk prir t the initiatin f treatments, at which time the pled by treatment grup within a rm. Sperm mtility, animals were 38 wk f age. Als, 10 Arbr Acres hens cncentratin, and viability were determined fr each f the same age were caged individually in a clsed- pl f semen. Mtility was scred frm 1 (least mtile) sided huse with cnventinal envirnmental cntrls. t 5 (mst mtile) using the swirl methd (Cherms, The hens were divided equally amng 1 grups f 1968; Graham et al., 198). Sperm cncentratin was cages. The rsters were given 10 g f feed per bird estimated by using the packed sperm vlume methd f per day f a standard breeder diet (915 kcal ME/kg, Maeza and Buss (1976), while sperm viability was 15% CP, and 3% Ca). The hens were fed the same determined with the flurmetric methd f Bilgili and breeder diet t maintain the recmmended weight. Bth Renden (1984). Semen was diluted with minimum hens and rsters were expsed t a phtperid f 16 essential medium (Hwarth, 1981) t a cncentratin f h f light per d. 50 millin sperm/50 µl and inseminated int hens. At The diet f six f the males in each rm was 1400 h, six f the 1 grups f hens were inseminated supplemented with 0.15% ASA, while the remaining six with semen frm the three ASA replicates, while the males in each rm received the C diet. The ther six grups f hens were inseminated with semen experimental diets were initiated 1 wk prir t heat frm the three C replicates ( grups per replicate per stress treatment. After this prestress wk, a 4 wk heat treatment). stress perid was cnducted. During the first wk f the heat stress perid, the ambient temperature in each Fertilizatin Characteristics: During the first wk f the rm was increased t 9 C (Maximum = 30±.6 C; heat stress perid, in viv sperm-egg penetratin was Minimum = 8±1 C). Fr the remaining 3 wk f the study, determined in each egg laid pstinseminatin. The the temperature in each rm was further elevated t methd used fr determining sperm-egg penetratin 3 C (Maximum = 33±1 C; Minimum = 31±1 C). Relative was that f Bramwell et al. (1995). The perivitelline layer humidity was recrded daily with a VWR digital frm vipsited eggs was remved, fixed with 0% hygrmeter mdel Relative humidity averaged frmalin, and stained with Schiff's reagent. The number 4±3% during the 4 wk f the experiment. f sperm penetratin hles were cunted in a 1.35 mm area surrunding the germinal disc. Bdy temperature: Bdy temperature was determined During the remaining three wk f the heat stress perid, with a Cle-Parmer thermistr thermmeter Mdel 840 daily sperm-egg penetratin was analyzed fr three f and a YSI thermistr prbe 403 inserted 6 cm int the the grups f hens inseminated with semen frm each rectum. Rectal bdy temperature f each male was f the ASA replicates and fr three f the grups f hens measured during the secnd thrugh the eighth d f the inseminated with semen frm each f the C replicates. prestress wk at 0800 hr befre feeding. During the heat Fr determinatin f candling fertility and hatchability, stress perid, rectal bdy temperature was measured eggs frm the remaining six grups f hens were during the first d f each wk. Because bdy temperature incubated. Candling fertility f each egg laid changes after feeding (Wilsn et al., 1989) and because pstinseminatin was measured at 10 d f incubatin. the level f aspirin in the bld wuld theretically be the All unhatched eggs were pened t determine true highest after feeding, measurements were made at 1 h fertility. Prir t incubatin, eggs were stred in a cler befre feeding and at h after feeding during the heat at 13.3 C and set nce every wk. Hen-day egg stress wk. In additin, at the end f every wk f the study, prductin averaged 70% thrughut the experiment. feed cnsumptin and mrtality were calculated fr each Therefre, apprximately seven eggs were analyzed fr replicate f males. either sperm-egg penetratin r candling fertility fr each replicate during each d pstinseminatin. Individual male semen characteristics: On the third and sixth d f each wk f the study, semen characteristics Statistical analysis: Randmized cmplete blck were analyzed fr each individual male. The semen designs with either split-plts r split-split plts in time characteristics measured included the fllwing: semen (time f d, d, r wk) were used t analyze the data. The vlume, packed sperm vlume, and sperm viability. cntrlled temperature rms served as blcks. Dietary Packed sperm vlume was determined using the treatment grups, which were crssed with rms, were technique f Maeza and Buss (1976). Sperm viability the experimental units. Linear and curvilinear regressin was analyzed by btaining the percentage f dead analyses were als utilized t determine the relatinship sperm with the flurmetric methd f Bilgili and amng treatment means ver time (d r wk). Percentage 571

3 Fig. 1: Rectal bdy temperature f males fed a cntrl Fig. : Semen vlume prduced by males fed a diet r a diet cntaining 0.15% acetylsalicylic cntrl diet r a diet cntaining 0.15% acid during each wk f the experiment acetylsalicylic acid during each wk f the (treatment by wk interactin, P>0.5, SEM = 0.11, experiment (treatment by wk interactin, n = 3). The cmbined treatment means are P<0.08). Birds were expsed t 1 C during als displayed. Birds were expsed t 1 C week 0. During week 1, the ambient during week 0. During week 1, the ambient temperature was elevated t 9 C. Fr weeks temperature was elevated t 9 C. Fr weeks thrugh 4, the ambient temperature was thrugh 4, the ambient temperature was increased further t 3 C. Values are displayed increased further t 3 C. A significant linear as the mean ±SEM. Means with different increase in bdy temperature acrss weeks 0 superscripts are significantly different (P<0.05). thrugh 3 f the experiment was nted fr the Values represent the replicate means ver the cmbined treatment means (y = 0.18x , r 3rd and 6th d f the wk fr 3 replicates f 6 = 0.90, P<0.05). Letter superscripts indicate a males each (n = 6). significant wk effect (P<0.01). Cmbined treatment means with different superscripts are with feeding. Supplementatin f 0.15% ASA in the male significantly different [(P<0.05, SEM = 0.088, n briler breeder's diet decreased feed cnsumptin by = 6 (3 replicates time diets)]. apprximately 4 g/bird/d as cmpared t feed cnsumptin f rsters fed the C diet (Table ). data were transfrmed using arcsin square rt Mrtality appeared t be unaffected by dietary treatment. transfrmatin. Hwever, statistical patterns were similar between transfrmed and untransfrmed data, Individual male semen characteristics: As indicated in therefre nly untransfrmed data will be presented. Fig., a significant treatment grup by wk f treatment Student Newman Keul's sequential range test was used interactin was btained fr semen vlume. Semen t separate interactin means (Steel and Trrie, 1980). vlume was elevated in the C fed birds but nt in the ASA fed birds during the secnd wk f heat stress. Packed Results Bdy temperature: Rectal bdy temperature, as measured befre feeding, was similar between the C and ASA fed males during the prestress wk (Fig. 1). The means acrss treatment grups increased linearly frm the prestress wk until the third wk f heat stress and sperm vlume appeared t be unaffected by dietary treatment (Fig. 3), althugh a quadratic decline was nted amng weekly means with increasing expsure t heat stress. A significant treatment grup by wk f treatment interactin was als nted fr sperm viability (Fig. 4). During the furth wk f heat stress, the then decreased. Additinally, bdy temperature percentage f dead sperm prduced by the ASA fed increased apprximately 0.7 C within h f feeding (Table 1). Hwever, the additin f ASA t the diet did nt suppress this increase in bdy temperature assciated males was significantly greater than that f the C fed males. In additin, the percentage f dead sperm prduced during the third d f the wk was less than that 57

4 Fig. 3: Packed sperm vlume f semen prduced by males fed a cntrl diet r a diet cntaining 0.15% acetylsalicylic acid during each wk f the Fig. 4: The percentage f dead sperm in semen experiment (treatment by wk interactin, P<0.11). prduced by males fed a cntrl diet r a diet The cmbined treatment means are als cntaining 0.15% acetylsalicylic acid during each displayed. Birds were expsed t 1 C during wk f the experiment (treatment by wk week 0. During week 1, the ambient temperature interactin, P<0.056). Birds were expsed t was elevated t 9 C. Fr weeks thrugh 4, the 1 C during week 0. During week 1, the ambient ambient temperature was increased further t temperature was elevated t 9 C. Fr weeks 3 C. A significant quadratic relatinship thrugh 4, the ambient temperature was between packed sperm vlume and wk f the increased further t 3 C values are displayed experiment was detected fr the cmbined as the mean ±SEM. Means with different treatment means (y = -1.5x x , r = superscripts are significantly different (P<0.05). 0.9, P<0.08). Individual treatment means are Values represent the replicate means ver the displayed as mean±sem. Individual treatment 3rd and 6th d f the wk fr 3 replicates f 6 means represent the replicate means ver the males each (n = 6). A significant d effect was 3rd and 6th day f the wk fr 3 replicates f 6 als btained [Day 3 = 14.4%, Day 6 = 17.9%, males each (n=6). P<0.007, SEM = 0.1, N = 30 (3 replicates times 5 wk times treatments)]. prduced during the sixth d f the wk (14.4 vs 17.9, SEM =.1, P <.007). While sperm-egg penetratin by sperm frm the ASA fed males appeared t decrease ver weeks f the Pled semen characteristics: All f the pled semen experiment, n linear cmpnent was detected. Similar characteristics were similar between the C and ASA fed quadratic declines in sperm-egg penetratin ver each males (Table ). The treatment grup by wk f treatment d pstinseminatin were seen when hens were interactins fr the pled semen characteristics were inseminated with semen frm either C r ASA fed birds nt statistically significant. (Fig. 7). Fertility, as a result f inseminating hens with semen Fertilizatin characteristics: As shwn in Fig. 5, the frm ASA fed males, decreased linearly frm the secnd main effect means fr in viv sperm-egg penetratin, t the furth wk f heat stress treatment (Fig. 8). N candling fertility, and hatchability f fertile eggs were nt weekly linear decline in fertility was nted when hens significantly different between the C and ASA treatment were inseminated with semen frm C males. Hwever, grups. In additin, n interactin between treatment means ver each 7 d pstinseminatin perid revealed and length f expsure t heat stress was seen fr any a quadratic descent in fertility f the C males. A much f the fertilizatin characteristics. Hwever, ver the fur sharper linear decline ver d pstinseminatin was wk f the heat stress perid, sperm-egg penetratin f nted fr fertility f the ASA fed males (Fig. 9). In additin, sperm frm the C males decreased linearly (Fig. 6). the line fr the ASA treatment grup was fund t have a 573

5 Fig. 6: In viv sperm egg penetratin when hens were Fig. 5: In viv sperm egg penetratin, candling fertility, inseminated with semen frm males fed a and the hatchability f fertile eggs when hens cntrl diet r a diet cntaining 0.15% were inseminated with semen frm males fed a acetylsalicylic acid during each wk f the cntrl diet (pen bars) r a diet cntaining experiment (treatment by wk interactin, P>0.50). 0.15% acetylsalicylic acid (hatched bars). Values Birds were expsed t 1 C during week 0. are displayed as the mean ± SEM. Fr sperm During week 1, the ambient temperature was egg penetratin (P>0.4), values represent the elevated t 9 C. Fr weeks thrugh 4, the main effect means ver 4 wk and the nd ambient temperature was increased further t thrugh the 8th d pstinseminatin fr three 3 C. A significant linear decline in sperm egg replicates (n = 84). Fr fertility (P>0.14) and penetratin ver wk f the experiment was nted hatchability (P>0.1), values represent the main fr the cntrl treatment grup (y = -.7x +., effect means ver 3 wk and the nd thrugh the r = 0.9, P<0.04). Values are displayed as 8th d pstinseminatin fr three replicates (n = mean ± SEM. Values represent the replicate 63). means ver the nd thrugh the 8th d pstinseminatin fr 3 replicates (n = 1). significantly greater slpe and smaller intercept than the C treatment grup line. The hatchability f fertile eggs t birds receiving n ASA. Pssible explanatins, fr the was similar between the C and ASA treatment grups ppsing results btained in the current study as during each wk f the experiment (Fig. 10). cmpared t thse f Adams and Rgler (1968) and Glick (1963), may invlve the age f the birds and Discussin feeding methds used. The present research used Previus research has shwn that the bdy temperature sexually mature birds that were feed restricted and nt f briler breeders will increase fllwing expsure t chicks that were given feed ad libitum as in this previus temperatures as lw as 9 and 3 C, as was bserved research. in the present study (McDaniel et al., 1995a and 1995b). Even thugh rsters were feed restricted,.15% dietary Althugh earlier accunts indicate that ASA in the pultry ASA was detrimental t feed cnsumptin during the diet will decrease bdy temperature during heat stress heat stress perid. McDaniel et al. (1993a) has shwn cnditins (Adams and Rgler, 1968; Glick, 1963), n that feeding White Leghrn breeders 0.1 and 0.% ASA such effect was seen in the present study. Even after ad libitum did nt alter feed cnsumptin, hwever, feeding, when bdy temperature (Wilsn et al., 1989) 0.4% ASA did significantly decrease feed cnsumptin and plasma ASA are mst likely the highest, ASA failed as cmpared t birds n a C diet. It is pssible that in t decrease the bdy temperature f heat stressed the present study a subptimal level f ASA was used fr rsters. Wilsn et al. (1973) nted an apparent maximizing its antipyretic prperties while preventing any increase in bdy temperature f heat stressed White harmful side-effects (Weissmann, 1991). Leghrn chicks given 3, 30, r 300 mg ASA as cmpared Previus research has shwn that fertility is negatively 574

6 Fig. 7: In viv sperm egg penetratin during each d Fig. 8: Candling fertility when hens were inseminated pstinseminatin when hens were inseminated with semen frm males fed a cntrl diet r a with semen frm males fed a cntrl diet r a diet cntaining 0.15% acetylsalicylic acid during diet cntaining 0.15% acetylsalicylic acid each wk f the experiment (treatment by wk (treatment by d pstinseminatin interactin, interactin, P<0.5). Birds were expsed t 1 C P>0.66). Significant quadratic declines in sperm during week 0. During week 1, the ambient egg penetratin ver d pstinseminatin were temperature was elevated t 9 C. Fr weeks seen fr the cntrl treatment grup ( y = -10.1x thrugh 4, the ambient temperature was x , r = 0.98, P <0.0003) as well as increased further t 3 C. A significant linear the acetylsalicylic acid treatment grup (y = -9.1x decline in fertility ver wk f the experiment was x , r = 0.93, P<0.0047). Bth lines nted fr the acetylsalicylic acid treatment grup had similar slpes and intercepts (P>0.17). (y = -16x , r = 0.97, P<0.10). Values are Values are displayed as mean ± SEM. Values displayed as mean ± SEM. Values represent the represent the replicate means ver 4 wk fr 3 replicate means ver the nd thrugh the 8th d replicates (n = 1). pstinseminatin fr 3 replicates (n = 1). crrelated with male rectal bdy temperature when bdy fertility fr the ASA treatment grup. Several studies have temperature is increased as a result f heat stress demnstrated that male reprductive perfrmance is (McDaniel et al., 1995b). Pssibly because dietary ASA depressed during cnditins f excessive feed did nt lwer the bdy temperature f heat stressed restrictin (Parker and McSpadden, 1943; Parker and rster in the present research, fertility and sperm-egg Arsctt, 1964; Sharlin et al., 1981; Rbinsn et al., 1993). penetratin were nt imprved in cmparisn t feeding The percentage f fertile eggs btained in the present males the C diet. In fact, when analyzed with linear and study, when semen frm heat stressed males fed the C curvilinear regressin, fertility ver each d diet was used t inseminate hens, was high as pstinseminatin was lwer fr birds receiving the ASA cmpared t previus research when briler breeder diet than fr birds given the C diet, even thugh semen males were heat stressed at a similar temperature. characteristic were similar between the tw treatment McDaniel et al. (1995a) fund that candling fertility f grups. Additinally, fertility f ASA fed birds and nt C heat stressed males was nly 55% after expsure t 3 birds decreased linearly with each wk f study. It is C fr 3 wk, whereas in the present study fertility f C fed pssible that the level f dietary ASA used in this study males was 85% during the 3 wk f treatment. Pssibly was t extreme. McDaniel et al. (1993b) fund that the lwer relative humidity (4%) maintained in the feeding layer breeder hens 0.% ASA did nt alter fertility present study, as cmpared t that (40%) maintained by whereas.4% decreased fertility. The decrease in feed McDaniel et al. (1995a), may nt have been high enugh cnsumptin, bserved in the present study when birds t greatly depress fertility. It is well dcumented that an were fed ASA, may partially accunt fr the reductin in increase in envirnmental water vapr decreases 575

7 Table 1: Effects f feeding acetylsalicylic acid (ASA) t heat stressed males n bdy temperature (C) befre and after feeding 1 Time Cntrl ASA Mean SEM P < Befre feeding After feeding Mean SEM P < Values represent the replicate means ver 4 wk f 3 replicates with 6 birds each (n = 1). Table : Effects f feeding acetylsalicylic acid (ASA) t heat stressed males n mrtality, feed cnsumptin, and pled semen characteristics 1 Treatment Mrtality Feed Cnsumptin Sperm Packed Sperm Dead Sperm -(%)- -(g/bird/d)- Mtility Vlume -(%)- -(%)- Cntrl ASA SEM P < Values represent the replicate means ver 4 wk fr 3 replicates f 6 birds each (n = 1). Fig. 9: Candling fertility during each d Fig. 10: The hatchability f fertile eggs when hens were pstinseminatin when hens were inseminated with semen frm males fed a inseminated with semen frm males fed a cntrl diet r a diet cntaining 0.15% cntrl diet r a diet cntaining 0.15% acetylsalicylic acid during each wk f the acetylsalicylic acid (treatment by d experiment (treatment by wk interactin, P>0.5). pstinseminatin interactin, P>0.48). A Birds were expsed t 1 C during week 0. significant quadratic decline in sperm egg During week 1, the ambient temperature was penetratin ver d pstinseminatin was seen elevated t 9 C. Fr weeks thrugh 4, the fr the cntrl treatment grup (y = 3x x , r = 0.99, P<0.0001). Fr the acetylsalicylic ambient temperature was increased further t 3 C. Values are displayed as mean ± SEM. acid treatment grup a much sharper linear decline ver d pstinseminatin was nted (y = -5.x , r = 0.98, P <0.0001). Each line has different slpes and intercepts (P<0.05). Values are displayed as mean ± SEM. Values represent the replicate means ver 3 wk fr 3 replicates (n = 9). 576 Values represent the replicate means ver the nd thrugh the 8th d pstinseminatin fr 3 replicates (n = 1). perfrmance f pultry expsed t elevated temperatures (Adams and Rgler, 1968; Smith and

8 Oliver, 1971). This depressing effect is mst likely due t a lss in evaprative cling efficiency at high relative humidities (Sturkie, 1986). Hwever, as was mentined previusly, bdy temperature was significantly increased in the present study when males were heat stressed, indicating a respnse during expsure t increased envirnmental temperatures even at 4% relative humidity. In cnclusin, 0.15% ASA in the heat stressed male's diet did nt decrease bdy temperature. In additin, 0.15% dietary ASA appears t be detrimental t fertility f heat stressed briler breeder males. References Adams, R.L. and J. C. Rgler, The effects f dietary aspirin and humidity n the perfrmance f light and heavy breed chicks. Pult. Sci. 47: Bilgili, S.F. and J.A. Renden, Flurmetric determinatin f avian sperm viability and cncentratin. Pult. Sci., 63: Bramwell, R.K., H.L. Marks and B. Hwarth, Quantitative determinatin f spermatza penetratin f the perivitelline layer f the hen's vum as assessed n vipsited eggs. Pult. Sci., 74: Cherms, F.L., Variatins in semen quality and the relatinship f semen quality t fertility in turkeys. Pult. Sci., 47: Glick, B., Influence f acetylsalicylic acid n the bdy-temperature f heat-stressed chickens. Nature 00: 603. Graham, E.F., D.S. Nelsn and M.K.L. Schmehl, 198. Develpment f extender and techniques fr frzen turkey semen.. Fertility trials. Pult. Sci., 61: Hwarth, B., Preservatin f the fertilizing capacity f cck semen incubated in vitr at 41 C. Pult. Sci., 60: Hutchins, M.O., W.S. Newcmer and R.H. Thayer, 196. Effects f sdium salicylate n thyrid functin in heat-stressed chickens. Pult. Sci., 1: Maeza, A.S. and E.G. Buss, Sperm cncentratin and sperm numbers as related t fertility in chickens. Pult. Sci., 55: 059 (Abstr.). Marks, H.L., Pssible relatinship between packed sperm vlume and egg mass in dmestic fwl. Separatum Experientia, 34: McDaniel, C.D., J.M. Balg, M. Freed, R.G. Elkin, R.H. Wellenreiter and P.Y. Hester, 1993a. Respnse f layer breeders t dietary acetylsalicylic acid. 1. Effects n hen perfrmance and eggshell quality. Pult. Sci., 7: McDaniel, C.D., J.M. Balg, M. Freed, R.G. Elkin, R.H. Wellenreiter, T. Kuczek and P.Y. Hester, 1993b. Respnse f layer breeders t dietary acetylsalicylic acid. 3. Effects n fertility and hatchability f embrys expsed t cntrl and elevated incubatin temperatures. Pult. Sci., 7: McDaniel, C.D., R.K. Bramwell and B. Hwarth, Jr., 1995a. The male cntributin t briler breeder heat stress infertility as determined by sperm-egg penetratin and sperm strage within the hen's viduct. Pult. Sci., 74 (submitted). McDaniel, C.D., R.K. Bramwell, J.L. Wilsn and B. Hwarth, Jr., 1995b. Fertility f male and female briler breeders fllwing expsure t elevated ambient temperatures. Pult. Sci., 74: Oluyemi, J.A. and A. Adebanj, Measures applied t cmbat thermal stress in pultry under practical trpical envirnment. Pult. Sci., 58: Parker, J.E. and G.H. Arsctt, Energy intake and fertility f male chickens. J. Nutr., 8: Parker, J.E. and B.J. McSpadden, Influence f feed restrictin n fertility in male dmestic fwls. Pult. Sci., : Reid, B.L., A.A. Kurnick, J.M. Thmas and B.J. Hulett, Effect f acetyl-salicylic acid and xytetracycline n the perfrmance f White Leghrn breeders and briler chicks. Pult. Sci., 43: Rbinsn, F.E., J.L. Wilsn, M.W. Yu, G. M. Fasenk and R.T. Hardin, The relatinship between bdy weight and reprductive efficiency in meat-type chickens. Pult. Sci., 7: Sharlin, J.S., B. Hwarth, Jr., F.N. Thmpsn and R.D. Wyatt, Decreased reprductive ptential and reduced feed cnsumptin in mature White Leghrn males fed aflatxin. Pult. Sci., 60: Smith, A.J. and J. Oliver, Sme physilgical effects f high envirnmental temperatures n the laying hen. Pult. Sci., 50: Steel, R.G.D. and J.H. Trrie, Principles and Prcedures f Statistics. A Bimetrical Apprach. nd ed. McGraw-Hill Bk C., Inc., New Yrk, NY. Sturkie, P.D., Pages in: Avian Physilgy. 4th ed. Springer-Verlag, New Yrk, NY. Weissmann, G., Aspirin. Sci. Am., 64: Wilsn, H.R., A.E. Armas, I.J. Rss, C.D. Baird and R.A. Vitle, Antipyretics and heat tlerance f White Leghrn chicks. Flrida Scientists, 36: Wilsn, H.R., F.B. Mather, R.L. Brigmn, E.L. Besch, V.P. Dugan and N.Z. Buls, Feeding time and bdy temperature interactins in briler breeders. Pult. Sci., 68: