Methionine
requirement of juvenile Japanese flounder Paralichthys olivaceus
M.S. Alam, S.IK. Teshima, M. Ishikawa, S. Koshio-2000
Journal of the World Aquaculture Society, 31 (4) :
618-626 (from Current Contents)
Abstract:
Growth studies were conducted to determine the
dietary methionine requirement of juvenile Japanese flounder Paralichthys
olivaceus. A basal diet was formulated to contain 50% crude protein from
casein and gelatin, as intact protein sources, supplemented with crystalline
L-amino acids (CAA), to correspond to the amino acid pattern found in the
whole body protein of the juvenile Japanese flounder, except methionine.
Test diets contained six graded levels of L-methionine 0.53, 0.83, 1.13,
1.43, 1.73, and 2.03% of diet (dry matter basis) or 1.06, 1.66, 2.26, 2.86,
3.46 and 4.06% of protein. To prevent leaching losses of water-soluble amino
acids, CAA were pre-coated with carboxymethylcellulose (CMC), and diets were
further bound with both CMC and K-carrageenan after addition of the
pre-coated CAA. Weighing about 2.80 g, each triplicate group of the juvenile
flounder were fed test diets twice a day (5% of body weight) for 40 d.
Survival rate, specific growth rate, feed conversion efficiency and apparent
protein retention were significantly (P < 0.05) affected by dietary
methionine concentrations. The optimum dietary level of methionine in the
presence of 0.06% of dietary cystine for Japanese flounder juvenile was
estimated by using break point analysis. The values determined based on
weight gain and feed efficiency were 1.49% of diet (or 2.98% of protein) and
1.44% of diet (or 2.88% of protein), respectively. These requirement values
are close to the methionine level of flounder whole body protein.
(Kagoshima Univ, Fac Fisheries, Shimoarata 4-50-20,
Kagoshima 8900056, Japan)