P. monodon juvenileswere sampled fromnormal andMSGS ponds andwere divided into smallnegative,
large-negative, small-positive and large-positive groups, depending on the size of the shrimp and
whether they were LSNV-negative or LSNV-positive. Individual shrimp were measured for duration of each
molt stage and molt interval. Levels of MIH1 and CHH1 transcripts were determined from the optic lobe, using
real-time reverse transcriptase–polymerase chain reaction. The results revealed that the small-positive and
the small-negative shrimp did not differ in durations of molt stages or molt intervals, as well as on the levels
of MIH1 transcript in the optic lobe,MIH1 peptide in the optic lobe and hemolymph, or ecdysteroids in the hemolymph.
Differences inmolting activities and related transcript and hormones were observed between the smalland
large-sized shrimp, but not in the status of LSNV infection.While levels of CHH1 transcript in the optic lobe of
both small-negative and small-positive shrimp did not differ, levels of CHH1 peptide, as well glucose, in the
hemolymph of the small-positive shrimp were significantly lower than those of the small-negative group. Levels
of glycogen in the hepatopancreas of the small-positive shrimp were also significantly higher than that of the
small-negative ones. The results suggest that growth retardation in MSGS shrimp is related to the suppression
of the release of CHH1 peptide by LSNV invasion in the zona fasciculata, consequently causing decreased
hepatopancreatic glycogenolysis and persistent hypoglycemia, resulting in growth stunting