An inherited retinopathy in commercial breeding chickens

Abstract

SUMMARYImpaired vision was observed in individual birds from several related flocks of layer breeding chickens. The condition was usually apparent by eight weeks of age. Affected birds were unable to perceive food particles on a flat surface or to negotiate a 50 mm bridge, although apparently able to discern large objects and to respond to bright light. On ophthalmoscopic examination of the fundus the choroidal vasculature was usually more readily visualised than in normal chickens and in addition discrete white streaks were often seen to extend peripherally from the base of the pecten. Cataract formation was frequently present by several months of age. The electroretinograms of two affected birds were of abnormally low amplitude. Light microscopy of the retinas of most birds exhibiting blindness showed a generalised reduction in the number of photoreceptors and in the thickness of the outer nuclear layer, although in others there were no obvious abnormalities. The linear fundus lesions represented abrupt thinnings of the retina in which, to a varying degree, the retinal pigment epithelium and photoreceptor inner and outer segment, outer nuclear and outer plexiform layers were disorganised or absent. A mating of affected individuals produced progeny of which 13/14 were obviously ' blind, indicating an hereditary basis for the condition.

Collagen organization in the chicken cornea and structural alterations in the retinopathy, globe enlarged (rge) phenotype—An X-ray diffraction study

“…Rge is an autosomal recessive disease of chickens characterized by progressive retinal dysfunction and blindness by $30 days post-hatch (Curtis et al, 1987(Curtis et al, , 1988Inglehearn et al, 2003;Montiani-Ferreira et al, 2003. The rge phenotype has been shown to result from an inframe 3 bp deletion in the cone beta-transducin gene GNB3, leading to a D153del mutation which destabilizes the protein (Tummala et al, 2006).…”

Clinical features of the retinopathy, globe enlarged (rge) chick phenotype

“…This is a naturally-occurring autosomal recessive retinal disorder leading to blindness [11,12]. The gene locus has been mapped to chicken chromosome one [13].…”

The US–India Nuclear Agreement: Revisiting the Debate

“…45 The right of reprocessing is crucial for the success of India's civil programme, therefore during the negotiations India 'consistently defended its right to reprocess nuclear fuel'. 46 As Sethi avers, 'The real potential of nuclear energy to meet its [India's] energy requirements emerges from the possibility of using the energy remaining in spent fuel in fast reactors which breed more fissile material than they consume, and thus provide the promise of sustainable energy security'. Kakodkar opposed the related issue of second-phase fast breeder reactors, placing them under the IAEA safeguards.…”