Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra?
The domestic fowl (Gallus gallus domesticus) originates from the forests in South-east Asia. It may be correct to assume that the visual system of the domestic fowl is still adapted to light that is filtered through the green forest canopy. In modern poultry production, however, light is provided vi...
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| Formato: | H2 |
| Lenguaje: | Inglés sueco |
| Publicado: |
SLU/Dept. of Animal Environment and Health (until 231231)
2018
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| Materias: |
| _version_ | 1855572224032899072 |
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| author | Annerstedt, Pauline |
| author_browse | Annerstedt, Pauline |
| author_facet | Annerstedt, Pauline |
| author_sort | Annerstedt, Pauline |
| collection | Epsilon Archive for Student Projects |
| description | The domestic fowl (Gallus gallus domesticus) originates from the forests in South-east Asia. It may be correct to assume that the visual system of the domestic fowl is still adapted to light that is filtered through the green forest canopy. In modern poultry production, however, light is provided via artificial luminaires and in low intensities to control feather pecking and cannibalism. Compared with production and reproduc-tion, the effect of light intensity on visual abilities is not researched as much. The aim with this study was to compare spatial resolution threshold between layers and its ancestor the red jungle fowl, between different light spectra and light intensities.
Chickens were held in one of three light treatments during part of the rearing, and during training and testing. One light treatment represented the light in the natural habitat of red jungle fowl, called the jungle light. Another light treatment was the standardized illuminant D65 which represents average daylight. The control light did not have UV-light, which can be discriminated by birds, included as the two other light treatments had. Twelve layers and twelve jungle fowls were trained to discrim-inate between a square-wave grating and a homogenous grey picture inside a Skin-nerbox and tested in four different light intensities. Each bird was tested with increasing spatial frequency of the grating, and when discrimination failed, the spatial resolution threshold of that chicken was said to have been reached.
A significant difference in spatial resolution threshold was found between light treatments for red jungle fowls. The group with D65-light had a mean threshold of 5.023 cycles per degree of visual angle (c/deg) compared with 3.794 c/deg in the jun-gle light group (p-value < 0.05). Significant differences were also found between the breeds in the lowest light intensity in the jungle light and control light treatment. In the control light group, the mean spatial resolutions of the layers was 4.095 c/deg and 2.783 c/deg among the red jungle fowl (p-value < 0.05). In the jungle light group, the mean spatial resolution of the layers was 4.017 c/deg and 2.373 c/deg among the red jungle fowl (p-value < 0.05). A significant difference in spatial resolution threshold between the breeds in the lowest light intensity may be seen as an evidence that layers have adapted to the dim light conditions which is common in commercial layer facilities.
To further deepen the understanding of how spatial resolution threshold is affected by light spectra, testing in one colour of light at a time would be interesting, as well as measuring production and welfare parameters in a larger scale behavioural study with the jungle light. |
| format | H2 |
| id | RepoSLU13315 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2018 |
| publishDateSort | 2018 |
| publisher | SLU/Dept. of Animal Environment and Health (until 231231) |
| publisherStr | SLU/Dept. of Animal Environment and Health (until 231231) |
| record_format | eprints |
| spelling | RepoSLU133152019-02-25T13:38:04Z Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? Tröskelvärden i spatial upplösningsförmåga hos värphöns och röda djungelhöns : finns det skillnader som beror på ljusintensitet eller ljusspektra? Annerstedt, Pauline spatial resolution threshold layer red jungle fowls visual acuity The domestic fowl (Gallus gallus domesticus) originates from the forests in South-east Asia. It may be correct to assume that the visual system of the domestic fowl is still adapted to light that is filtered through the green forest canopy. In modern poultry production, however, light is provided via artificial luminaires and in low intensities to control feather pecking and cannibalism. Compared with production and reproduc-tion, the effect of light intensity on visual abilities is not researched as much. The aim with this study was to compare spatial resolution threshold between layers and its ancestor the red jungle fowl, between different light spectra and light intensities. Chickens were held in one of three light treatments during part of the rearing, and during training and testing. One light treatment represented the light in the natural habitat of red jungle fowl, called the jungle light. Another light treatment was the standardized illuminant D65 which represents average daylight. The control light did not have UV-light, which can be discriminated by birds, included as the two other light treatments had. Twelve layers and twelve jungle fowls were trained to discrim-inate between a square-wave grating and a homogenous grey picture inside a Skin-nerbox and tested in four different light intensities. Each bird was tested with increasing spatial frequency of the grating, and when discrimination failed, the spatial resolution threshold of that chicken was said to have been reached. A significant difference in spatial resolution threshold was found between light treatments for red jungle fowls. The group with D65-light had a mean threshold of 5.023 cycles per degree of visual angle (c/deg) compared with 3.794 c/deg in the jun-gle light group (p-value < 0.05). Significant differences were also found between the breeds in the lowest light intensity in the jungle light and control light treatment. In the control light group, the mean spatial resolutions of the layers was 4.095 c/deg and 2.783 c/deg among the red jungle fowl (p-value < 0.05). In the jungle light group, the mean spatial resolution of the layers was 4.017 c/deg and 2.373 c/deg among the red jungle fowl (p-value < 0.05). A significant difference in spatial resolution threshold between the breeds in the lowest light intensity may be seen as an evidence that layers have adapted to the dim light conditions which is common in commercial layer facilities. To further deepen the understanding of how spatial resolution threshold is affected by light spectra, testing in one colour of light at a time would be interesting, as well as measuring production and welfare parameters in a larger scale behavioural study with the jungle light. Den domesticerade hönan (Gallus gallus domesticus) härstammar från skogarna i sydvästra Asien. Man kan anta att de visuella förmågorna hos domesticerade höns-fåglar fortfarande är anpassade till den sortens ljus som filtreras genom den gröna växtmassan. I modern äggproduktion tillförs ljus istället via artificiell väg och i låga ljusintensiteter för att kontrollera fjäderplockning och kannibalism. Jämfört med pro-duktionsegenskaper och reproduktion har det inte forskats lika mycket på visuella förmågor hos höns. Syftet med denna studie var att jämföra den spatiala upplösnings-förmågan mellan värphöns och dess anfader röda djungelhöns, mellan olika ljus-spektrum och mellan olika ljusintensiteter. Kycklingarna i studien hölls i en av tre olika ljusmiljöer under delar av uppväxten, och under träning och tester. Ett av experimentljusen representerade det ljus som finns i de röda djungelhönsens naturliga habitat, kallat djungelljuset, och ett annat experimentljus var det standardiserade D65-ljuset som ska representera naturligt dagsljus. Kontrolljuset innehöll inte UV-ljus, som fåglar kan uppfatta, till skillnad från de två andra experimentljusen. Tolv värphönshybrider och tolv röda djungelhöns blev tränade att särskilja mellan ett fyrkantsvågsgitter och en homogen grå bild i fyra olika ljusintensiteter i en Skinnerbox. Varje fågel testades genom att öka den spatiala frekvensen av gitter och när de inte kunde särskilja mellan bilderna sades det att kycklingens högsta spatiala upplösningsförmåga hade uppnåtts. En signifikant skillnad i spatial upplösningsförmåga fanns mellan grupperna av röda djungelhöns. Gruppen med D65-ljus hade ett medelvärde på sitt tröskelvärde på 5.023 cykler per visuell grad (c/deg), jämfört med 3.794 c/deg hos gruppen med djungelljus (p-värde < 0.05). Signifikanta resultat erhölls i jämförelsen mellan ra-serna i den lägsta ljusintensiteten i djungelljuset och kontrolljuset. I kontrolljusgrup-pen hade värphönsen ett medelvärde för spatial upplösningsförmåga på 4.095 c/deg och de röda djungelhönsen hade ett medelvärde på 2.783 c/deg (p-värde < 0.05). I djungelljusgruppen hade värphönsen ett medelvärde för spatial upplösningsförmåga på 4.017 c/deg och de röda djungelhönsen hade ett medelvärde på 2.373 c/deg (p- värde < 0.05). Ifall fler kycklingar hade inkluderats i studien hade de signifikanta skillnaderna mellan raserna i den lägsta ljusintensiteten kunnat tolkas som ett bevis för att värphöns har anpassat sig till de låga ljusintensiteterna som är vanligt förekommande inom äggproduktionen. För att ytterligare lära sig mer om hur den spatiala upplösningsförmågan påverkas av olika ljusspektrum skulle man kunna testa den i olika separata färger, såväl som att mäta produktions- och välfärdsparametrar i en större beteendestudie i djungelljuset. SLU/Dept. of Animal Environment and Health (until 231231) 2018 H2 eng swe https://stud.epsilon.slu.se/13315/ |
| spellingShingle | spatial resolution threshold layer red jungle fowls visual acuity Annerstedt, Pauline Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title | Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title_full | Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title_fullStr | Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title_full_unstemmed | Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title_short | Spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| title_sort | spatial resolution threshold in layers and red jungle fowls : are there differences due to light intensity or light spectra? |
| topic | spatial resolution threshold layer red jungle fowls visual acuity |