Effect of prolonged photoperiod on ocular tissues of domestic turkeys

Leis, Marina L.; Dodd, Mary Magdalene U.; Starrak, Gregory; Vermette, C.; Gomis, Susantha; Bauer, Bianca S; Sandmeyer, Lynne S; Schwean-Lardner, K.; Classen, H. L.; Grahn, Bruce H

doi:10.1111/vop.12395

Cited by 6 publications

(8 citation statements)

References 58 publications

(86 reference statements)

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“…The diameter of the cornea decreased, and the dorso-ventral diameter, medio-lateral diameter and anterior-posterior depth was increased ( Figure 5 ) [ 22 ]. In addition, these same birds reared under 23 L, as compared to 14 L, had evidence of ocular pathology, including reduced number of nuclei in both the outer and inner nuclear layer, a reduction in the thickness of the choroid as well as a significant increase in the incidence of cataract [ 23 ].…”

Section: Resultsmentioning

confidence: 99%

“…While we cannot say that welfare was compromised in the broilers reared under 23 L with respect to eye health (as only eye weight was monitored), we can hypothesize tthat this degree of ocular pathology may be a welfare issue. The added length of time that turkeys live in their environment demonstrate significant welfare challenges with regards to eye health, particularly with the development of cataracts, which can lead to intraocular inflammation and vision compromise [ 23 ].…”

Section: Resultsmentioning

confidence: 99%

“…Following that work, a similar study (repeated twice) was conducted using the same research facilities, with turkeys to 18 weeks of age, again exposed to the same lighting programs. Each of these studies have previously been published as individual works [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ], but this review will compare the effects on the two species.…”

Section: Introductionmentioning

confidence: 99%

“…Detailed materials and methods for these studies are outlined in the corresponding journal articles [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. To briefly outline these—the floor-barn facility used for both the broiler and turkey experiments is composed of eight individual rooms (two room replications per trial, with four trials for broiler studies and two trials for turkey studies), each with independent environmental control systems.…”

Section: Introductionmentioning

confidence: 99%

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Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare

Schwean-Lardner

Vermette

Leis

et al. 2016

Animals

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Simple SummaryAltering daylength in a poultry management program is a simple tool that can have immense impacts on productivity and bird welfare. It is not uncommon for lighting data derived from broiler research to be extrapolated to turkey production. This review of two studies (one with broilers and the second with turkeys), completed in the same research facility using the same lighting programs, shows evidence that some, but not all responses to graded daylengths are similar between these two species. It defines that daylength choices for turkeys should be based on research conducted with turkeys.AbstractDaylength used as a management tool has powerful implications on the welfare of both broilers and turkeys. Near-constant light results in many detrimental impacts, including lack of behavioural rhythms and circadian melatonin rhythms. Both are suggestive that sleep fragmentation could result in birds reared on long photoperiods, which can lead to the same negative health and physiological responses as total sleep deprivation. An indirect comparison of the welfare implications of graded levels of daylength on broilers and turkeys clearly indicate that long daylengths depress welfare by increasing mortality, reducing mobility, increasing ocular pathologies and changing behaviour in both species. Furthermore, long daylengths change melatonin secretion patterns and eliminate behavioural and melatonin circadian rhythms, which were measured in broilers in these works. However, feather pecking in turkeys was reduced when birds were exposed to long daylengths. Exactly how much darkness should be included in a management program to maximize welfare will depend on the species, the age of marketing, and in turkeys, bird gender.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare

Schwean-Lardner

Vermette

Leis

et al. 2016

Animals

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“…The examinations included chromatic pupillary light reflex (PLR) testing (Melan-100 unit, BioMed Vision Technologies, Ames, IA, United States), anterior segment biomicroscopy performed with a portable slit lamp (SL-17, Kowa, Tokyo Japan), and indirect ophthalmoscopy [IOP, (Heine Omega 200, Heine Instruments Canada, Kitchener, Ontario)]. Rebound tonometry (Tonovet, Tiolat, Helsinki, Finland) was used to estimate intraocular pressure ( Wahl et al, 2016 ; Leis et al, 2017 ).…”

Section: Methodsmentioning

confidence: 99%

Light Color and the Commercial Broiler: Effect on Ocular Health and Visual Acuity

et al. 2022

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Light is a critical management factor for broiler production, and the wavelength spectrum, one of its components, can affect bird physiology, behavior and production. Among all the senses, sight is important to birds, and their visual system possess several adaptations that allow them to perceive light differently from humans. Therefore, it is critical to consider whether the exposure to monochromatic light colors influences broiler visual ability, which could affect behavioral expression. The present study examined the effects of various light colors on the visual systems of broiler chickens. Ross 708 males were raised from 0 to 35 days under three wavelength programs [blue (dominant wavelengths near 455 nm), green (dominant wavelengths near 510 nm) or white]. Broilers were given a complete ophthalmic examination, including chromatic pupillary light reflex testing, rebound tonometry, anterior segment biomicroscopy and indirect ophthalmoscopy (n = 36, day 21). To assess ocular anatomy, broilers were euthanized, eyes were weighed, and dimensions were taken (n = 108, day 16 and day 24). An autorefractor was used to assess the refractive index and the corneal curvature (n = 18, day 26). To evaluate spatial vision, broilers underwent a grating acuity test at one of three distances–50, 75, or 100 cm (n = 24, day 29). Data were analyzed as a one-way ANOVA using the MIXED procedure or Proc Par1way for non-normally distributed data. Significant differences were observed for refractive index and spatial vision. Birds raised under blue light were slightly more hyperopic, or far-sighted, than birds raised under white light (P = 0.01). As for spatial vision, birds raised under blue light took less time to approach the stimulus at distances of 50 cm (P = 0.03) and 75 cm (P = 0.0006) and had a higher success rate (choosing the right feeder, P = 0.03) at 100 cm than birds raised under white light. Improvements in spatial vision for birds exposed to blue light can partially explain the behavioral differences resulting from rearing broilers under different wavelengths.

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Effect of photoperiod during incubation on embryonic temperature, hatch traits, and performance of 2 commercial broiler strains

Li¹,

McLean²,

MacIsaac³

et al. 2023

Poultry Science

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Effect of prolonged photoperiod on ocular tissues of domestic turkeys

Abstract: Exposing turkeys to a prolonged photoperiod induces significant ocular disease.

Cited by 6 publications

References 58 publications

Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare

Basing Turkey Lighting Programs on Broiler Research: A Good Idea? A Comparison of 18 Daylength Effects on Broiler and Turkey Welfare

Light Color and the Commercial Broiler: Effect on Ocular Health and Visual Acuity

Effect of photoperiod during incubation on embryonic temperature, hatch traits, and performance of 2 commercial broiler strains

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