|Sequential utilization of free amino acids, yolk proteins and lipids in developing eggs and yolk-sac larvae of barfin flounder Verasper moseri|
Ohkubo, N.; Matsubara, T. (2002). Sequential utilization of free amino acids, yolk proteins and lipids in developing eggs and yolk-sac larvae of barfin flounder Verasper moseri. Mar. Biol. (Berl.) 140: 187-196
In: Marine Biology. Springer: Heidelberg; Berlin. ISSN 0025-3162, more
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Changes in the contents of free amino acids (FAA), M r 170,000 lipovitellin (oLv B), that is the major yolk protein in ovulated eggs, and lipids were measured in developing eggs and yolk-sac larvae of barfin flounder (Verasper moseri) to elucidate the sequential utilization of these nutrient stocks before the .rst feed. Hatching takes place on the 10th day after fertilization at water temperature of 8 C, and the hatched larvae absorb almost all of their yolk masses within 21 days after fertilization. The total FAA content showed no change during the first 4 days, then decreased to about 13%of the initial level by the 13th day after fertilization. During the consumption of FAA, non-essential amino acids tend to decrease earlier than essential amino acids. The native molecular weight and immunoreactivity of M r 170,000 oLv B did not show any change during the first 16 days after fertilization, though the sodium dodecyl sulphate-polyacrylamide gel electrophoresis patterns of oLv B showed serial change. The oLv B contents, measured by quantitative immunodi fusion using antiserum against oLv B of ovulated eggs, were approximately stable during the 13 days after fertilization, then decreased rapidly until the end of yolk-sac absorption. Phospholipids (PL), which seem mostly to bind with lipovitellin-proteins, decreased gradually after hatching coincident with the decrease in oLv B and M r 330,000 lipoprotein. From these results, we conclude that there are three periods for sequential nutrient utilization in barfin flounder embryos and larvae: (1) pre- FAA utilization period, 0 -4th day; (2) FAA utilization period, 4th-13th day; (3) oLv B and PL utilization period, 16th -21st day post-fertilization.