抄録
Trend of pH value, changes in the amounts of water, total nitrogen, non-protein nitrogen, ether-extractives, crude ash, crude lipides, lipide-phosphorus and-nitrogen in developing rainbow trout eggs were measured, the results being shown in Table 1. The eggs, when transferred from ovarian fluid to water, absorbed abundant water, but decreased in weight on hatching, and then increased gradually after hatching as shown in Fig. 1.
In order that the bearing of these individual components on the egg development may be estimated as justly as possible, they are finally represented in gram per 100 grams of unfertilized eggs ( Table 2). The results obtained are summarized as follows:
1) The amount of water of the unfertilized eggs increased by 17.5g. due to the water uptake following the fertilization. On hatching, the water and solid matter decreased by about 4.4g. and 7.8g., respectively, owing to the detachment of egg capsule. The sac fry when a substantial amount of the yolk had been disappeared, retained the water about two times that of initial eggs.
2) Total nitrogen, ether extractives, and lipides were reduced by half during the course of development, but the non-protein nitrogen increased up to a value about five times as much as that of unfertilized eggs.
3) Ash content increased gradually.
4) On the whole, these increases or decreases became conspicuous with the start of the hatching. The consumption of total nitrogen, ether extractives, and lipides are thought to serve as the energy supply for the motion of embryo.
