Effects of selection to resistance on newcastle disease in japanese quail

B Jaworek
1978 Genetics Selection Evolution  
In a two-day selection experiment mice lines with high and low carbon clearance rate were established. The estimates of realized heritabilities are 0 . 30 in the " high " line and 0 . 25 in the " low " line. Correlated selection responses are discussed, especially spleen weight and tumor incidence. During the last few years some Danish mink farmers have observed a rather high frequency of death among kits of the Standard type. The deaths occur usually when the kits are about 6 weeks old, i. e.
more » ... 6 weeks old, i. e. about the weaning age. The state of health of the kits appears quite normal during sucking period. The affected kits die within two-three days after the first symptoms have been observed. Watery eyes are the first sign of the disease, followed by the sticking eyelids. Pathologic-anatomical observations have been carried out. The most remarkable signs were oedematic kidneys. Cytological examinations showed no difference from the normal caryotype., Biochemical investigations were performed on serum samples from normal and affected kits. These results demonstrated that the affected kits had 20 -100 times higher plasma tyrosine concentrations than those found for normal kits. Also unusual high concentrations of the carboxylic acids derived from tyrosine were observed, corresponding to a defect in the enzyme 4 -hydroxyphenylpyruvate dioxygenase. The plasma concentrations of the other protein amino acids were less, but significantly altered whereas this was not the case for Na, K, Ca, and Mg. It should be mentioned that the concentration of urea and creatinine was found 2 -5 times higher in affected kits compared to normals. Investigation concerning the genetics of the disease confirmed the hypothesis of a simple (Mendelian) recessive inheritance. In conclusion the disorder is inherited as a recessive character, due to homozygosity at a single locus. No indication of pleiotropic effect, coupling between genes, etc. has been observed. These results concerning the hereditary disease among mink show a parallelism to the hereditary disease in man known as hereditary tyrosinemia or hereditary tyrosinosis.
doi:10.1186/1297-9686-10-4-589b fatcat:3i5nm3sfevdbboxvaixrhcvv5u