Energy budget of Marsupenaeus japonicus postlarvae fed highly
unsaturated fatty acid-enriched and non-enriched Artemia nauplii
O.
Sumule, S. Koshio, S.-I. Teshima, M. Ishikawa-2003
Fisheries
Science, 69(4):
706
Abstract:
The
energy budget of Marsupenaeus japonicus postlarvae (PL) fed highly
unsaturated fatty acid-enriched (EA) and non-enriched (NEA) Artemia
nauplii was determined by equating energy intake (EI) with the
summation of energy channeled to feces (F ), metabolism (M ),
excretion (U ), growth (G) and exuvia (Ev).
Stage PL4 (mean wet weight 1.14 ± 0.31 mg, 14 days
post-hatching) of M. japonicus were reared in six 80 L circular
tanks, with three replicates, and fed EA and NEA for 21 days. The EI
was calculated from the energy content of consumed nauplii, M was
calculated from the summation of energy for routine metabolism, active
metabolism and heat increment based on oxygen consumption, U was
calculated from urinary loss based on ammonia excretion, G was
calculated from energy increase based on weight gain, Ev was
calculated from energy loss based on molting and F was obtained from
the difference between EI and the total of the other variables. The
values of EI, M and U were expressed as a function of
the wet body weight (W ) of PL in a power function: EI, M
or U = aW b, where a and b
were estimated by least squares regression after a logarithmic
transformation of the raw data. After 21 days, the growth rate of PL fed EA
was higher than those fed NEA. The daily ingested energy of 5 mg wet wt
of M. japonicus PL was partitioned as follows: 13.9% to fecal loss,
50.9% to metabolism, 4.8% to urinary loss, 24.6% to growth and 5.8% to
exuvia for the EA group; 40.2% to fecal loss, 28.9% to metabolism, 4.0% to
urinary loss, 21.8% to growth and 5.2% to exuvia for NEA group. Assimilation
and gross conversion efficiencies were higher, but net conversion efficiency
lower, in the EA group compared with the NEA group. The higher essential
fatty acid intakes in the EA improved the growth of PL due to better
assimilation.
(Laboratory of Aquatic Animal Nutrition, Faculty of
Fisheries, Kagoshima University, Kagoshima, Kagoshima 890-0056, Japan