Progress 10/01/05 to 11/30/09
Outputs
OUTPUTS: Activation of the HPA axis is linked to depression of the HPT axis in avians. Male quail cloacal gland development and foam production show androgen dependency, and males selected for reduced (low stress, LS) rather than exaggerated (high stress, HS) plasma corticosterone (B) stress response show enhanced cloacal gland and testes development. LS hens also deposit more B into their egg yolks than do HS ones and random bred hens given B during egg formation produce offspring with an enhanced juvenile growth rate and heightened adult HPA responsiveness. Heightened adrenal stress responses are also associated with decreased reproductive performance in non-selected hens. Cloacal gland studies conducted in 2005 and egg fertility and hatchability studies done in 2006 showed that both genetic selection for exaggerated HPA axis responsiveness and maternal B treatment negatively impact the reproductive performance of both male and female HS offspring. In 2007, using two-way choice tests of the direction of first travel (DFT), affiliation preference, (AP) and time spent near (TSN) a female, adult focal LS and HS males were found to prefer an LS as opposed to HS hen (stimulus target) as a companion, regardless of maternal B treatments (control vs. B-implant). Maternal B-implant treatment also eliminated a control male offspring's (regardless of line) DFT towards, and AP for, an LS female and it caused males of both lines to spend more time near an HS female. Line, maternal B-treatment and their interactive influences on a male's TSN both LS and HS female progeny were stable short term. In 2007, we showed that growing under lifelong short (non-photostimulatory) days comparatively stymied both cloacal gland development and function (foam production) in HS males. In 2008, we found: 1) eggs from HS quail hens hatched much sooner than did eggs laid by LS hens, and 2) B-implant treatment of hens during egg formation shortened both stress lines' length of egg incubation (LEI), particularly so for HS hen eggs. It is known that stress-induced glucocorticoids can dampen learning and spatial memory via neuronal damage to the hippocampus. Cognition losses can be transient (associated with acute stress episodes) or permanent as in aged individuals who show chronic glucocorticoid-induced accelerated brain aging and neurodegeneration (dementia). Therefore, in 2009, under each temporal paradigm, the spatial memory responses of aged male LS and HS quail were assessed in a feed-baited 8-arm radial arm maze (RAM): at 255 d of age (quail who had experienced lifelong management stressors but who were otherwise never intentionally stressed, chronically stressed birds), on the next day post-brief restraint (acute stress), and on the next day without treatment (acute stress recovery). On Day 1, line effects were detected for the total number of RAM arm choices made (HS < LS), the number of correct entries made into RAM arms out of the first 8 choices (HS < LS), the time required to make a choice (HS > LS), and the number of feed pellets eaten (HS < LS). However, neither the effects of day of RAM testing nor its interaction with line further influenced these variables. PARTICIPANTS: The PI (Dr. Dan Satterlee), his Research Associate (Jason Schmidt) and former post-doctoral student (Dr. Raul Marin), and numerous graduate (Kyndal Davis, Ryan Andree, Jason Schmidt) and undergraduate (Shane Castille, Bob Zanes, Courtney Cole, Amy Hester, Kimberly LaRay, Ryan Doessher, Stephen Treese) students within the School of Animal Sciences of the LSU Ag Center participated in the work conducted. Within the LSU Ag Center alone, three (3) students conducted research work at the MS level from experiments reported herein (see above). In addition, two graduate students from Dr. Marin's lab at the University of Cordoba (Argentina) were hosted as visiting scientists to help in the conduct of some of the reported work- Jackie Kembro and Daniel Guzman. As a result, all of the above mentioned individuals received significant "training and professional development." In addition, in 2007, Dr. Judy Grizzle (another member of S-1020; UT-Knoxville Station scientist) collaborated with he PI on a study that examined the effects of T-2 myoctoxins on reproductive performance of the LS and HS quail. Results of that collaboration were significant but were not reported in this final Termination Report, as they should be included in Dr. Grizzle's final S-1020 report. TARGET AUDIENCES: Direct "target audiences" include: poultry geneticists, broiler and turkey breeder and egg-type chicken layer managers, poultry egg hatchery managers, broiler chicken and turkey producers, and quail producers. Indirect target audiences that benefited from the research would include all the "groups, market segments, and consumers" in the U.S. (and world wide) that consume poultry products. Many "efforts" were made by presentation of the results of experiments conducted in the form of formal classroom and laboratory instruction within the PI's PLSC 1049 (Poultry Production) and PLSC 4031 (Incubation and Hatchery Management) courses taught at Louisiana State University, as well as oral and poster presentations made at scientific meetings (e.g., at Poultry Science Association Annual meetings). The PI also made yearly Louisiana Station oral reports of all work conducted under S-1020 from 2005-2008 at the various USDA approved meeting sites across the USA. Dr. Satterlee also hosted the 2008 S-1020 meeting held in New Orleans, LA. Numerous publications in refereed journals such as Poultry Science and others (see Publications list) ensured that the experimental outcomes were also disseminated to a much larger scientific (national and international) base. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
During the 5-year S-1020 reporting period, many intuitively desirable traits were found to be associated with selection for reduced adrenocortical responsiveness. In addition, maternal B treatment during egg formation was oftentimes shown to be detrimental to reproductive function, particularly in offspring of HS mothers. Thus, collectively, our findings strongly suggest that: 1) avian geneticists need to consider incorporating selection for low plasma B response into the selection programs of the more commercially important poultry species, chickens and turkeys, and 2) poultry producers need to limit stress in the laying barn particularly in stocks considered to be "flighty" or "less docile." The 2005-2006 data support a case that adherence to these recommendations would likely be met with: heightened gonad weights, accelerated puberty, greater egg fertility and hatchability, and less early embryonic mortality. Our 2007 AP findings suggest that following these guidelines would also result in more appropriate mate selections (i.e., the choosing of LS hens by both LS and HS roosters). This is likely since APs in male and female control quail are known to be stable short term (as was confirmed in our 2007 stress line companionship studies) and highly predictive of mate choices. In addition, the 2007 findings of comparatively stymied cloacal gland development and foam production in HS males reared on short day lengths suggests that HS male quail held under non-stimulatory photoperiods likely had reduced testicular mass as well, since both cloacal gland measures are androgen dependent. In fact, we know that testes weight is reduced in HS males held under long day lengths. Since testis weight is highly correlated with daily sperm production, which is highly correlated with fertility, a connection between diminished fertility in males predisposed to heightened stress responsiveness (the HS genotype) continues to emerge. The 2008 findings that HS quail hen eggs hatched sooner than eggs of LS hens and that maternal B-implant treatment shortened the LEI in both quail lines, particularly in HS hen eggs, are also important to the poultry industry. Because stress during egg formation increases the deposition of egg yolk B, poultry geneticists, breeder egg producers, and hatchery managers would be well advised to consider the effects that a hen's genetic predisposition towards stressor-induced adrenocortical responsiveness and stress related to management practices at breeder farms may have on altering LEI and, therefore, the optimal time to pull chicks during hatching. The latest (2009) findings of line differences in spatial memory on Day 1 of RAM testing in aged stress line quail may reflect lifelong management-induced stress episodes that periodically produced higher plasma B responses in HS than LS quail which under lied the observed HS quail memory deficits. If this is proven, then it is yet another demonstration of an advantage to producers of rearing stocks selected for reduced stress responsiveness- greater ability to find feed resources needed to support the energy requirements of survivability and gamete production.
Publications
- Satterlee, D. G., C. A. Cole, and S. A. Castille, 2007. Maternal corticosterone further reduces the reproductive function of male offspring hatched from eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness. Poultry Sci. 86: 572-581.
- Satterlee, D. G., M. Tong, S. A. Castille, and R. H. Marin, 2007. Cloacal gland growth differences in high and low plasma corticosterone stress response line male quail reared under short daylengths. Poultry Sci. 86: 1213-1217.
- Labaque, M. C., D. G. Satterlee, D. A. Guzman, R. H. Marin, 2007. Ontogeny of the cloacal gland in male Japanese quail classified in a T-maze. Poultry Sci. 86: 2013-2019.
- Satterlee, D.G., A. Hester, K. LeRay, and J. B. Schmidt, 2008. Influences of maternal corticosterone and selection for contrasting adrenocortical responsiveness in Japanese quail on developmental instability of female progeny. Poult. Sci. 87: 1504-1509.
- Schmidt, J. B., C.A. Cole, R. B. Zanes, and D.G. Satterlee, 2009. Length of incubation and hatchling body weight in Japanese quail selected for reduced or exaggerated adrenocortical responsiveness to brief restraint. Brit. Poult. Sci. 50:266-271.
- Schmidt, J.B., S. T. Treese, and D. G. Satterlee, 2009. Maternal corticosterone reduces egg fertility and hatchability and increases the numbers of early dead embryos in eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness. Poult. Sci. 88:1352-1357.
- Schmidt, J.B., R. M. Andre', K. A. Davis, S. M. Treese, and D. G. Satterlee, 2009. Influence of maternal corticosterone treatment on egg incubation length of eggs laid by quail hens selected for divergent adrenocortical stress responsiveness. Brit. Poult. Sci. (In press; CBPS-2008-345).
- Suhr, C. L., J. B. Schmidt, S. T. Treese, and D. G. Satterlee, 2009. Short-term spatial memory responses in aged Japanese quail selected for divergent adrenocortical stress responsiveness. Poult. Sci. (Submitted for publication; PS-09-00288).
- Hayward, L. S., D. G. Satterlee, and J. C. Wingfield, 2005. Japanese quail selected for high plasma corticosterone response deposit high levels of corticosterone in their eggs. Physiol. Biochem. Zool. 78: 1026-1031.
- Marin, R. H., and D. G. Satterlee, 2006. Differences in the onset of puberty in female Japanese quail divergently selected for adrenocortical responsiveness. Arch. Zootech. 55: 195-202.
- Satterlee, D. G., C. A. Cole, and S. A. Castille, 2006. Cloacal gland and gonadal photoresponsiveness in male Japanese quail selected for divergent plasma corticosterone response to brief restraint. Poultry Sci. 85: 1072-1080.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Several aspects of Objective 2 (Determine physiological and behavioral basis for management of reproduction) of Specific Aim 2 (Identify and characterize endocrine and physiological components of reproductive fitness in poultry) were addressed in 2008. The results of length of egg incubation (LEI) studies performed on eggs laid by control or corticosterone (B) treated hens from lines selected for divergent adrenocortical responsiveness were used as two chapters of an M.S. thesis to partially satisfy the degree requirements of Mr. Jason Schmidt who graduated from LSU in the fall of 2008. The results of these two LEI experiments were presented in an oral presentation made by the PI at the 97th Annual Meeting of the Poultry Science Association (PSA) held in Niagara Falls, Canada in July of 2008 and as the Louisiana Station report at the Annual Meeting of the USDA S-1020 group held in New Orleans, Louisiana, in October, 2008. It should be noted that both scientists and members of the poultry industry were present at both the Canadian and New Orleans meetings. In addition, the LEI data have been sent as two manuscripts for publication to British Poultry Science (the 1st experiment is "In press" and the 2nd study is under review). Results from the third and final chapter of Mr. Schmidt's thesis (quail stress line and maternal B treatment effects on hen-day egg production, egg fertility, total and fertile egg hatchability, and embryonic mortality) have been reported during previous S-1020 Annual Meetings as part of past Louisiana Station reports, so these findings will not be repeated under the Outcomes/Impacts section below. Mr. Schmidt has, however, also recently presented these older data orally at the 2008 PSA meeting in Canada and he has recently submitted a paper representing these studies to the Journal of Poultry Science. Thus, the information being generated by the Louisiana Station continues to be widely disseminated amongst the scientific community and members of the poultry industry. PARTICIPANTS: Besides myself (the PI), my Research Associate and M.S. graduate student, Mr. Jason Schmidt, worked on this project. In addition, an undergraduate student, Mr. Stephen Treese, also helped. TARGET AUDIENCES: The direct target audiences of this project are the scientific community and members of the poultry industry. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Another reproductive consequence of selection in quail for exaggerated (HS; high stress) rather than reduced (LS; low stress) plasma corticosterone (B) response to brief mechanical restraint was demonstrated. In two separate studies, eggs from HS quail hens were found to hatch much sooner than eggs laid by LS hens. In addition, in the second study, B-implant treatment (sub-Q implants) of hens during egg formation also shortened both quail stress lines' length of egg incubation (LEI), an effect that was more evident in the eggs of HS hens. Changes in B during chick embryogenesis affect metabolism (e.g., gluconeogenesis, lypolysis), lung maturation and surfactant production, and may play a role in the processes of egg hatching. However, only a scant and controversial literature exists concerning the effects of in ovo B on the LEI. Considering the roles that B plays on chick embryo development, and because more yolk B is found in the eggs of random bred Japanese quail hens implanted with B during egg formation than in controls, and because both unstressed and stressed HS quail hens deposit more B into their egg yolks than do LS hens, the study of the interactive effects of quail stress line with maternal B treatment during egg formation on LEI was justified. The findings that eggs from HS quail hens hatched sooner than did eggs laid by LS hens and that B-implant treatment of hens during egg formation shortened both quail stress lines' LEI, but more so in HS hen eggs, have significant implications for the poultry industry because it has been shown in birds that stress during egg formation increases the deposition of egg yolk B. Thus, poultry geneticists, breeder egg producers, and hatchery managers may all wish to consider the effects that a hen's genetic predisposition towards stressor-induced adrenocortical responsiveness and stress related to management practices at breeder farms may have on altering LEI and, therefore, the optimal time to pull chicks during hatching.
Publications
- Schmidt, J. B., C. A. Cole, R. B. Zanes, and D. G. Satterlee, 2008. Length of incubation and hatchling body weight in quail selected for reduced or exaggerated adrenocortical responsiveness to brief restraint. Brit. Poult. Sci. (Manuscript ID CBPS-2008-128; In press).
- Schmidt, J. B., R. M. Andree', K. A. Davis, S. M. Treese, and D. G. Satterlee, 2008. Influence of maternal corticosterone treatment on egg incubation length of eggs laid by Japanese quail hens selected for divergent adrenocortical stress responsiveness. Brit. Poult. Sci. (Manuscript ID CBPS-2008-345; submitted).
- Schmidt, J. B., D. G. Satterlee, and S. M. Treese, 2008. Maternal corticosterone reduces egg fertility and hatchability and increases the number of early dead embryos in eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness. Poultry Sci. (Manuscript ID PS-08-00513; submitted).
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: The studies concerning the interactive influences of quail stress line and life-long rearing under short day length on male reproductive function were published in Poultry Science in 2007. These studies were also conducted to partially fulfill the requirements of an undergraduate's (Courtney Cole) senior-level Special Problems Course in poultry science. In addition, the results of the photoperiod studies and those from the study of the influences of quail stress line*maternal corticosterone treatment on male progeny's affiliation preferences were presented at the 2007 U.S.D.A. Multistate Regional Research Project S-1020 Meeting, "Enhancing Reproductive Efficiency of Poultry (formerly S-285)" held at Jekyll Island, GA. The affiliation preference studies are also part of an M. S. student's (Ryan Andree) research data that will be used to satisfy his graduate research degree requirements. Mr. Andree is also preparing a paper on these studies that will soon be submitted for
publication to Poultry Science. Thus, the 2007 research covered under LAB03756 is being broadly shared with scientific communities using various venues.
PARTICIPANTS: Daniel G. Satterlee, PI; Jason Schmidt, Research Associate and graduate student; Shane Castille, Research Associate; Ryan Andree, graduate student, Courtney Cole, undergraduate student. Organization: School of Animal Sciences.
TARGET AUDIENCES: The target audiences for this project include commercial poultry breeders, hatchery managers, avian geneticists, and poultry scientists.
PROJECT MODIFICATIONS: None.
Impacts
In 2007, yet another apparently permanent negative reproductive consequence of selection in quail for exaggerated (HS; high stress) rather than reduced (LS; low stress) plasma corticosterone (B) response to stress was demonstrated. Similar to previous findings using stimulatory (long day) photoperiods, growing under lifelong short days comparatively stymied cloacal gland growth (CGG) and function (foam production; FOAM) in HS males. Because CGG and FOAM are androgen dependent traits, it is most likely that HS males held under non-stimulatory photoperiods also have reduced testicular mass (TM). We have shown this to be the case in past studies that have used long day lengths. In avians, because TM is highly correlated with daily sperm production which is highly correlated with fertility, a connection between diminished fertility in males predisposed to heightened stress responses continues to emerge. Thus, in managing commercial avians, care should be taken to avoid
environmental stress and genetic selection for reduced adrenocortical responsiveness should be considered. In a second study that used two-way behavior choice tests of the direction of first travel (DFT), affiliation preference (AP), and time spent near a female (TSNF), we found that adult LS males, regardless of exogenous maternal B influences, preferred LS hens as companions. HS male offspring from control and B-treated dams affiliated more with LS hens as well. Maternal B-implant treatment also eliminated a control male offspring's (regardless of line) DFT towards, and AP for, a LS female. Hen B-implant treatment also caused male offspring of both lines to spend more time near a HS female. Line, maternal B-treatment and their interactive effects on all male progeny's TSNF (LS or HS) were stable short term. APs in male random bred Coturnix are known to be both stable (short term, as has been confirmed in the present studies) and highly predictive of mate choices. Therefore, because
both LS and HS males preferred LS females as companions, outcomes apparently irrespective of the divergent selection used in the stress lines, it is likely that mate choice studies in the lines would show an enhanced desirability of all males to mate with females of the LS genotype. Because of the many intuitively desirable traits associated with selection for reduced B responsiveness, the present data continues to support our contention that avian geneticists should strongly consider selection for reduced stress response. The data that showed hen B-implant treatment also caused male offspring of both lines to spend more time near a HS female sounds another cautionary note- that poultry breeders who choose to select for the LS trait need further to be careful to minimize hen stress during egg formation. Hen stress is known to not only increase egg yolk B, heighten HPA responsiveness in adults derived from stressed mothers, and produce a host of deleterious effects on their production
performance and animal well being, but the present results also indicate that male progeny companionship preference, and therefore likely their sexual preference, will also be altered to favor females of the HS genotype.
Publications
- Satterlee, D. G, C. A. Cole, and S. A. Castille, 2007. Maternal corticosterone further reduces the reproductive function of male offspring hatched from eggs laid by quail hens selected for exaggerated adrenocortical stress responsiveness. Poultry Sci. 86: 572-581.
- Satterlee, D. G., M. Tong, S. A. Castille, and R. H. Marin, 2007. Cloacal gland growth differences in high and low plasma corticosterone stress response line male quail reared under short daylengths. Poultry Sci. 86: 1213-1217.
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Progress 01/01/06 to 12/31/06
Outputs
Stressor-induced plasma corticosterone (B) release (activation of the hypothalamic-pituitary-adrenal axis; HPA) can depress the hypothalamic-pituitary-gonadal axis in avians. For example, in male quail, selection for exaggerated (high stress, HS) rather than reduced (low stress, LS) plasma B stress response reduces testes weight, as well as cloacal gland volume (CVOL) and foam production (CFP), the latter two traits known to be androgen dependent. HS hens also deposit more B into egg yolks than LS ones and quail hens given B produce chicks that have a reduced growth rate and adults with heightened HPA responsiveness. We have also found maternal B challenge during egg formation negatively affected the typically superior reproductive function (higher CVOL) of LS males and produced even further declines in CFP of males hatched from eggs laid by HS hens given B. Herein, we tested the influences of no B (empty silastic implants; CON) or B-filled implants on the fertility
(FERT) and hatchability (HATCH) of eggs laid by LS and HS hens and on the reproductive performance of their female offspring. While maternal B did not affect FERT of eggs laid by LS hens, B-treatment even further decreased FERT of eggs from HS hens beyond a lesser, but significant, depression in FERT seen in the HS-CONs. Both total and fertile HATCH was decreased in eggs of the HS-B-implanted hens. The depression in fertile egg HATCH was explained by an elevation in the percent of early-dead embryos seen in the broken out eggs of the HS-B-implanted hens. Percent late-deads and pipped eggs were unaffected by stress line or maternal B treatment. Bodyweight, however, was depressed in both sexually immature and mature female offspring of HS-B-implanted hens. Puberty (measured by both the age at first and at 25% hen-day egg production; HDEP) was also delayed in females derived from HS-B-implanted mothers; and, weekly and cumulative HDEP was depressed in HS compared to LS offspring
regardless of maternal B treatment. Small incidences of retained right oviduct were also seen in HS-B, HS-CON, and LS-B offspring, while no LS-CONs showed this abnormality. Both selection for exaggerated HPA responsiveness and maternal B treatment negatively affects the reproductive function of HS female offspring.
Impacts
This research warns the producer of the potential negative impact that stress can have on the reproductive performance of breeder and laying hens. It further tells avian geneticists that selection for reduced stress responsiveness in commercially important stocks may provide a simple and effective means to improve FERT and HATCH of eggs laid by hens reared under modern-day intensive confinement systems- housing conditions that are oftentimes unavoidably stressful. Such selection, and/or attention to reduction of stress in the laying barn, would also serve as "insurance" policies against the many deleterious effects that stress can have on both male and female breeder-bird reproductive performance.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
Activation of the hypothalamic-pituitary-adrenal (HPA) axis, evidenced by increased plasma corticosterone (B), is linked to depression of the hypothalamic-pituitary-testicular (HPT) axis in avians. Male quail cloacal gland development and foam production shows androgen dependency, and males selected for reduced (low stress, LS) rather than exaggerated (high stress, HS) plasma B stress response show enhanced cloacal gland and testes development. LS hens also deposit more B into their egg yolks than do HS hens and random bred hens given B produce offspring with a reduced juvenile growth rate and heightened adult HPA responsiveness. These relationships led us to assess changes in the reproductive physiology of male offspring hatched from eggs laid by LS and HS hens challenged with no B (via empty silastic-implants; controls, CON) or with B-filled implants during egg formation. Cloacal gland area (CAREA) and volume (CVOL), the intensity of cloacal gland foam production
(CFP), and the proportion of individuals that produced cloacal gland foam (PICF) was measured weekly from 4 to 11 wk of age. At 15 wk, body weight (BWT), testes weight (TWT), and TWT relative to BWT (RTWT) was determined. HS-B hens showed a marked reduction in hen-day egg production (HDEP) when compared to the other treatment groups that shared normal and higher HDEP rates. While cloacal gland size of the male offspring was unaffected by the effects of stress line and maternal B treatment at the prepubescent age of 4 wk, both CAREA and CVOL differed in time and magnitude of response as follows: LS-CON > LS-B = HS-CON = HS-B at 5 and 6 wk of age; and, LS-CON > LS-B > HS-CON = HS-B from 7 to 11 wk of age. In support of these findings, beginning at 6 wk of age, CFP also showed similar significant segregations of line*maternal B-treatment effects across time. By 8 wk, and weekly thereafter, CFP of all four treatment groups differed as follows: LS-CON > LS-B > HS-CON > HS-B. Treatment
differences in PICF generally mimicked CAREA, CVOL, and CFP findings from 4 - 8 wk of age, but by 11 wk, all males were essentially producing at least some foam. BWT did not differ by treatment group at 6 wk of age, but by 15 wk of age, TWTs were similarly depressed in both HS groups compared to the two LS groups. However, similarly higher 15 wk BWTs found in the LS-CON and HS-B treatment groups contributed to differences (a,b,c P < 0.05) in RTWT as follows: LS-CON, a; LS-B, b; HS-CON, ac; and, HS-B, c. Both genetic alteration of the HPA axis and maternal B treatment influences appear to negatively affect the HPT axis of HS male offspring.
Impacts
Corticosterone (B) is considered to be the "avian stress hormone." Natural egg yolk deposition of additional maternal B from quail genetically selected for exaggerated B release to stress (high stress or HS hens), and particularly in HS hens supplemented with B, produced severe declines in reproductive performance of male offspring in comparison to the performance of males hatched from mothers selected for low stress (LS) and not given B (LS controls; best situation) or LS mothers given B. Because testes weight (TWT) was relatively enhanced in the LS control, and even LS mothers given B, and because TWT is associated with daily sperm production, it is likely that selection of LS fowl would lead to enhanced fertility in male offspring. These findings indicate that avian geneticists would be well served by considering selecting commercially important poultry stocks for reduced stress responsiveness.
Publications
- Hayward, L. S., D. G. Satterlee, and J. C. Wingfield, 2005. Japanese quail selected for high plasma corticosterone response deposit high levels of corticosterone in their eggs. Physiol. Biochem. Zool. 78(6): 1026-1031.
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