This report summarizes research achievements on the breeding, feed, and nutrition of Japanese quail performed at the Laboratory of Animal Genetics and Breeding, Department of Agriculture, Okayama University, between 1973 and 2008.
The study included analysis of inbreeding depression and heterosis, which are important subjects in breeding. Secondly, the genetic parameters useful for selection were identified and the sexing of newborn chicks utilizing sex-linked inheritance was investigated. As problems related to feed and nutrition, the reduced excretion of nitrogen (N) and phosphorus (P), the utilization of a cochineal residue, and the effects of red salmon astaxanthin, palm oil, and astaxanthin supplementation on eggs functions were investigated.
In quail, inbreeding depression was noted in overall productive characters, and the depression was marked in reproductive characters, such as hatchability. The genetic load was calculated using the equation: －logeS＝A＋BF. On crossbreeding between highly inbred lines of Japanese quail, marked heterosis was noted in the hatchability, viability,
and egg production rate.
Analysis of early embryonic development showed that the number of mitotic cells, mitotic index, and 3H-thymidine and 3H-uridine uptakes were lower in the inbred embryos compared with those of hybrid embryos, indicating important
Basic information for the selective breeding of quail, heritability of characters, such as the body weight, muscle mass, skeleton, and egg characteristics were accumulated; accumulated information suggested the possibility of selective
breeding with regard to these characters.
Sexing of newborn quail chicks utilizing sex-linked inheritance was performed. Mating males of the brown line and females of the normal line, all male chicks had normal plumage colors, whereas all females had brown plumage colors, which allowed simple sexing.
The supplementation of low-CP feed with essential amino acids and low-CP, low-P feed with phytase improved the growth of chicks, increased the egg production rate, and reduced N and P excretions. Phytase supplementation enhanced tibial growth in the early growth period, and reduced perosis and the mortality of chicks. When female chicks were fed a cochineal residue at 6 weeks of age, the egg production rate was similar to that of chicks fed fish meal, showing the possibility of substitution with fish meal.
The yolk color was improved by supplementation with red salmon astaxanthin, palm oil, and astaxanthin. The yolk color improved with increases in the supplemented amounts of palm oil and astaxanthin. Astaxanthin added to feed was transferred to the egg yolk, and the antioxidative capacity improved as the amount added increased.
To further clarify the characteristics of quail as experimental animals, and to improve their productivity as livestock, a continuation in both basic and applied research is indispensable.