The effects of intermittent light stimulation on chickens genetically predisposed to generalized convulsions are described. Epileptic chickens (homozygous recessive) convulse when exposed to intermittent light stimulation at 10–25 flashes per second, whereas normal (homozygous dominant) and carrier (heterozygous) hatch mates are not affected. The resting electroencephalogram (EEG) of epileptic chickens is markedly different from that of their nonconvulsive hatch mates, being characterized by high-amplitude slow waves with periodic spikes and spike–wave complexes. Prior to the onset of light-induced seizures, high-voltage spikes, at the same frequency as the stimulus, appear in all leads of the epileptic EEG. For a short time after a convulsion the EEG of epileptic chickens remains flattened, suggesting decreased electrical activity similar to the postictal depression seen in the EEG of human epileptics.
Two trials were conducted with two different lines of chickens to determine whether a gene for sex-linked imperfect albinism (sal-s) affected various egg production traits. In a line with relatively good egg production, sexual maturity was delayed for albino compared with nonalbino hens, but overall egg production by albinos was higher. The increased production resulted in eggs with reduced yolk and shell weights. Albumen weights were not affected, and because the eggs from albinos were smaller, Haugh unit scores were higher. In another trial, sexual maturity of hens of a heavy line was not affected by the genotype, but these hens did not receive controlled lighting during the growing period. Egg production curves of these hens were very similar to those seen in the first trial. The laying house mortality rates were not affected by the sal-s gene, despite several periods of high environmental temperature. These trials suggest that sal-s could be used in a sex-linked cross of commercial layers or broiler breeders.
Hybrids were produced between an African male and several Pilgrim female domestic geese. Partial karyotypes revealed a difference in the fourth largest pair of autosomal chromosomes. This chromosome pair was metacentric in the African, submetacentric in the Pilgrim, and heteromorphic in the hybrids. A similar difference between the putative wild ancestors of the African and Pilgrim breeds has been reported by others. These findings provide cytological evidence to support the traditional opinion that the African breed was derived from the Asiatic swan goose (Anser cygnoides) and the Pilgrim breed was derived from the European greylag goose (Anser anser).
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