Progress 10/01/04 to 09/30/09
Outputs
OUTPUTS: Results were disseminated through scientific publications. PARTICIPANTS: Graduate students and farm animal technicians TARGET AUDIENCES: The turkey industry PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
High environmental temperatures during the summer months have devastating effect on breeder hens reproductive performance. We investigated the effects of conditioning breeder hen turkeys to high environmental temperature on egg production during the summer months. Using LED lamps, we have established that the photo sexual responses of female turkeys are wavelength dependent and the far end of the visible spectrum (red band), more specifically the 630 nm wavelength is the most stimulatory to egg production. To optimize light intensity for the 630 nm wavelength which gave the best egg performance, we investigated the effect of several Light intensities (0.5, 3.0, 6.0 and 18.0 FC) from 630 nm wavelength LED lamps on egg production. Turkeys were subjected to temperature treatments at 20 weeks of age and were limited to 6 hrs per day. Temperature treatments included: 1) Control, room temperature was between 50 degrees F and 60 degrees F; 2) Birds were subjected to 75 degrees F increasing by 5 degrees F every two weeks and ending at 95 degrees F when the birds were 29 weeks of age, 3) The same as Treatment (2) excepting each temperature cycle was only for one week. There was no temperature control for the in between weeks, and 4) The conditioning temperature treatment started at 27 weeks of age for only 3 weeks; staring at 85 degrees F and increasing by 5 degrees F for the next two weeks. The best 27 week egg production was that of hens receiving 3 weeks of heat preconditioning starting at 27 weeks of age for only 3 weeks. Their average egg production was 4.16 eggs/hen/week, during the 27 week production period. The lowest average egg production was that of hens receiving the 10 week period of preconditioning (3.43 eggs/hen/week). The control group average egg production was 3.86 eggs/hen/week during the 27 week production period. The results clearly indicate that heat preconditioning can be beneficial and detrimental to egg production depending on the severity of the preconditioning temperature and the age at which birds at the initiation of the treat. Egg production was comparable among the four light intensity treatments (0.5, 3.0, 6.0 and 18.0 FC) from LED lamps at 630 nm wavelength. This is the first study showing that a light intensity at a 0.5 FC is as effective as an 18.0 FC in stimulating egg production.
Publications
- El Halawani, M. E. 2008. Effect of thermal conditioning during the prebreeder period on breeder hen turkey's reproductive performance. Gobbles 65 (4):10-13
- El Halawani, M. E. 2009. Light intensity requirement for breeder hen turkeys. Gobbles 66 (4):4-6.
- El Halawani, M. E. 2010. Effect of Thermal Conditioning on Breeder Turkeys Reproductive Performance. Gobbles 67 (4):7-8.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: It is a common observation that breeder hen turkeys photostimulated in the month of May (in Minnesota) are susceptible to a sudden increase in environmental temperature that results in a devastating effect on their egg production. This is especially true when the increase in environmental temperature occurs during peak egg production. Even though hens' photostimulated later in the year come into lay at times when environmental temperatures are high, they continue to lay at a high rate. This observation suggests that hens which come into lay during the summer appear to be conditioned (acclimatized) to high environmental temperature. Accordingly, it is hypothesized that conditioning of breeder hens to high temperature prior to photostimulation and egg laying enhances their resistance to heat stress. To test the hypothesis turkeys were subjected to the preconditioning temperatures ( 75 degrees F to 95 degrees F) between 20 weeks to 29 weeks of age. Preconditioning temperature treatments included: 1) Control, room temperature was between 50 degrees F and 60 degrees F; 2), Birds were subjected to 75 degrees F increasing by 5 degrees F every two weeks and ending at 95 degrees F when the birds were 29 weeks of age, 3) The same as Treatment 2) excepting each temperature cycle was only for one week. PARTICIPANTS: Graduate students and farm animal technicians. TARGET AUDIENCES: The turkey industry. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The breeder flock completed a 27 week egg production period. Peak egg production was comparable among all treatment groups between weeks 1-4 of photostimulation. Thereafter, there was a greater decline in egg production of control birds when compared to that of the heat preconditioned ones. The decline continued for two weeks before it stabilized. Egg production of hens that received the preconditioning heat treatment for 10 weeks from 75 degrees F at 20 weeks of age increasing 5 degrees every 2 weeks and reaching 95 degrees F at 29 weeks of age started to decline by the sixth week of photostimulation and continued to decline until week 18. The best 27 week egg production was that of hens receiving 3 weeks of heat preconditioning starting at 27 weeks of age for only 3 weeks. Their average egg production was 4.16 eggs/hen/week, during the 27 week production period. The lowest average egg production was that of hens receiving 10 week period of preconditioning (3.43 eggs/hen/week). The control group average egg production was 3.86 eggs/hen/week during the 27 week production period. The results clearly indicate that heat preconditioning can be beneficial and detrimental to egg production depending on the severity of the preconditioning temperatures and the age of birds at the initiation of treatments.
Publications
- El Halawani, M. E. 2008. Effect of thermal conditioning during the prebreeder period on breeder hen turkey's reproductive performance. Gobbles 65 (4):10-13.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Utilizing light emitting diodes (LEDs) to investigate wavelength requirement for breeder hen turkeys reproductive performance, we have shown that the longer the wavelength (from 630, 680 and 720 nm) in the red band of the spectrum the greater the decline in egg production. In these studies, LED panels did not have equal light distribution within pens. Light intensity was low and ranged from maximum of 3 FC directly under the light panel to less than 0.05 FC in the corners for the 630 nm. Lower light intensities were obtained with the 680 and 720 nm wavelengths. The objective of this study was to investigate the effect of shorter wavelength (600 nm), improved light intensities of the 630 nm wavelength by supplementing the 630 nm with 525 nm lamps. The last treatment was to supplement the 630 nm wavelength the 720 nm wavelength in the middle of egg production period. These resulted in the following four treatments: 1. 600 nm wavelength (provided by LED lamps 0.272 watts/m2;
142 lx). 2. 630 nm wavelength (provided by Light emitting diode (LED) 0.273 watts/m2; 32 lx) 3. 630 +525 nm wavelength (provided by LED lamps 0.387 watts/m2; 106 lx). 4. 630 + 720 nm (provided by LED, 0.435 watts/m2; 41 lx.
PARTICIPANTS: Graduate students and farm animal technicians
TARGET AUDIENCES: The turkey industry
Impacts
The breeder flock completed a 27 week egg production period. Peak egg production of hens that were photostimulated with the 630 nm wavelength at an intensity of 3.2 foot candles was 5.33 +/- 0.32 (mean +/- S.E.) eggs/hen/wk by the third week of photostimulation. Increasing light intensity to 14.2 foot candles and 10.6 foot candles by using the 600 nm wavelength or supplementing the 630 nm wavelength with a 525 wavelength, respectively, had no significant effect on peak egg production. Hens photostimulated with the 630 nm LED lamps laid significantly (P< 0.05) more eggs than hens photostimulated with the 600 nm wavelength (18 eggs) or the 630+525 nm (24 eggs) during the 27 week production season. These results are interpreted to suggest that the detrimental effect of the 525 nm and 600 nm wavelengths on egg production may be related to their shorter wavelength and activation of inhibitory retinal photoreceptors. The fact that light intensity is an important determinant
of reproductive performance and the 630 nm wavelength is proven to be superior to any other wavelength influencing egg production, a future study on the influence of light intensity provided by LED lamps of the 630 nm wavelength on the reproductive neuroendocrine system of breeder hen turkeys is necessary. The economic benefits for using LEDs for lighting breeder hen turkeys are clear. They improve reproductive performance, save energy, and reduce environmental impact.
Publications
- El Halawani, M.E. Differential Effects of Wavelength on Egg Production of Breeder Hen Turkeys. Proceedings of Turkey research review.1-5, 2007
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Progress 01/01/06 to 12/31/06
Outputs
In birds, changes in hypothalamic gonadotropin-releasing hormone-I (GnRH-I) content and release are correlated with reproductive stages. We examined the distribution and expression level of GnRH-I mRNA in anatomically discrete hypothalamic nuclei throughout the turkey reproductive cycle and following photostimulation. GnRH-I mRNA expression was determined using in situ hybridization in non-photostimulated (NPS), egg-laying (LAY), incubating (INC) and photorefractory (REF) hens. Overall, GnRH-I mRNA expression was greatest in the nucleus commissurae pallii (nCPa) and around the organum vasculosum lamina terminalis (OVLT), with less expression observed in the nucleus septalis lateralis (SL), cortico-habenula cortico-septum area, and within the nucleus preopticus medialis. GnRH-I mRNA expression was significantly increased in nCPa, OVLT, and SL after NPS hens (6L:18D) were exposed to a 30 or 90 min pulse of light beginning 14 h after first light (dawn). GnRH-I mRNA
abundance within nCPa, OVLT and SL was greater in LAY than in NPS and INC hens, while mRNA expression was least in REF hens. These results indicate that GnRH-I mRNA expression in birds is sensitive to light stimulation during the photosensitive period and can be used to more precisely characterize their different reproductive stages.We investigated the amount of energy emitted by LED diodes at the 630 nm wavelength on egg production of breeder hen turkeys.The effect 630 nm wavelength was tested at three energy levels including 187, 273 and 460uw/cm2. Egg production of control hens that were photostimulated with incandescent lamps peaked at 5.45+/-0.12 (mean+/-S.E.) eggs/hen/wk, by the fourth week of photostimulation. The highest peak production (5.86 eggs/hen/wk) was observed at the highest energy level (460 uw/cm2), on the third week of production. However, the overall average egg production during the 27 week period was greatest (4.011+/-0.13 eggs/hen/wk) at the 273 uw/cm2 energy
level; followed by the 460 uw/cm2 (3.92+/-0.12 eggs/hen/wk), 187uw/cm2 (3.77+/-0.22 eggs/hen/wk) and hens photostimulated with incandescent lamps (3.49+/-0.12 eggs/hen/wk)
Impacts
It is clear that egg production in female turkeys is wavelength dependent. Also, it clear that there is an antagonism between different wavelengths. Establishing the optimum wavelength for reproductive performance and the availability of appropriate LED lamps will improve the reproductive efficiency of breeder hen turkeys and in turn profitability
Publications
- Kang SW, Thayananuphat A, Rozenboim I, Millam JR, Proudman JA, El Halawani ME. 2006. Expression of hypothalamic GnRH-I mRNA in the female turkey at different reproductive states and following photostimulation. Gen Comp Endocrinol.146: 86-94.
- Jonsson JE, Afton AD, Alisauskas RT, Bluhm CK, El Halawani ME. 2006. Ecological and physiological factors affecting brood patch area and prolactin levels in arctic-nesting geese. The Auk 123(2):405-418.
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Progress 01/01/05 to 12/31/05
Outputs
The effects of turkey peptide histidine isoleucine (PHI) and turkey vasoactive intestinal peptide (tVIP) on prolactin (PRL) secretion and their physiological significance were studied in vitro and in vivo. In vitro studies were conducted using pituitary cell cultures from female turkeys. Both tVIP and tPHI stimulated PRL secretion from anterior pituitary cells in a dose response manner. However, tPHI was 100-fold less potent than tVIP in stimulating maximum PRL secretion in vitro. In addition, the highest dose (10-4 M) of tPHI inhibited its own PRL-releasing activity as well as that of VIP-stimulated PRL release. In the in vivo study, female turkeys were immunized with keyhole limpet hemocyanin (KLH; control), synthetic tPHI conjugate (KLH-tPHI), or synthetic tVIP conjugate (KLH-tVIP). Whereas, circulating PRL levels and nesting activity remained low and unchanged during the photo-induced reproductive cycle (i.e., experimental period) in tVIP-immunized birds, control
and tPHI-immunized turkeys showed a significant increase in plasma PRL levels and in the incidence of incubation behavior over time following photostimulation. These findings, taken together with earlier results, indicate that VIP is the sole physiological PRF in the turkey (avian species). We investigated the effect of light spectra in the near- (630 nm) middle-(680 nm) and far-red (720 nm) in the red band of the spectrum on the incidence of photorefractoriness and egg production utilizing LED Lamps. The average egg production during the 28-week experimental period were 56.77%, 60.71%, 56.63, and 48.39 for hens photostimulated with incandescent lamps (control), 630 nm, 680 nm, and 720 nm LED lamps, respectively. Hens photostimulated with the 630 nm LED lamps laid significantly (P<0.05) more eggs (7.28 eggs per hen) than their control incandescent hens. However, this response decreased with the increase in wavelength to 0.03 and -0.6 eggs/hen/wk of hens photostimulated with 680 nm and
720 nm wavelengths, respectively.
Impacts
Understanding the hormonal basis of incubation behavior (broodiness) in turkey hens may lead to the development of management tool(s) that prevents its expression and increase in egg production. Photorefractoriness (out of production - molted hens) is associated with ovarian regression and subsequent molt and remains a major mechanism limiting the continuous production of eggs. Our studies of the last two years have led to the novel findings suggesting that turkeys' egg laying activity is regulated by two light pathways, an inhibitory pathway and stimulatory pathway. Egg production is dependent upon the relative activation of the two pathways. The inhibitory pathway is activated by the green band of the light spectrum, and the stimulatory pathway is activated by the direct action of the red band on photoreceptors in the brain. It is hypothesized that photostimulating breeders with separate light sources, one stimulatory (red) and another inhibitory (green) will enable
one to optimize the red/green band ratio as well as the stimulatory wavelength in the red band to delay/prevent photorefractoriness and maximize egg production.
Publications
- Kulick RS, Chaiseha Y, Kang SW, Rozenboim I, El Halawani ME. 2005. The Relative importance of vasoactive intestinal peptide and peptide histidine isoleucine as physiological regulators of prolactin in the domestic turkey. Gen Comp Endocrinol. 142,267-273.
- Rozenboim I, Mobarkey N, Oshpiz O, Avital N, Heiblum R, El Halawani M. 2005. The role of retinal and extra-retinal photoreceptors in reproductive activities of broiler breeder hens. Poult Sc. 84 (Suppl. 1), 74.
- El Halawani ME. 2005. Light spectrum requirement to maximizing breeder hen turkey egg production. Proceedings of Turkey Research Review. PP.1-5.
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