Introduction
The prawn Macrobrachium americanum is a native crustacean found in the rivers of northwestern Mexico. CIIDIR-Sinaloa is working to establish conditions for the reproduction of M. americanum . Several variables have been controlled for the management of mating, as well as egg and larval development. During these studies, the mortality of berried females was common and warranted our attention. The goal of this study was to analyze the pro-phenol-oxidase system, total hemocyte count, coagulation, and mortality during female incubation..
Materials and methods
Four groups of 10 females were arranged: 1. Females with immature gonads, 2. Females five days post-ovulation, 3. Females five days before harvest, and 4. Males. Organisms were collected from the Sinaloa River, with an average weight of 74 g, and were reared for two months, fed tilapia meat and shrimp pellets at 29±2 °C until the reproduction season. At specified intervals, a sample of 50 µL of hemolymph was withdrawn to analyze coagulation time between the groups. Immediately afterward, a sample of 0.5 mL of hemolymph was collected from the ventral sinus in an anticoagulant solution to evaluate hemocyte count, pro-phenol-oxidase system, and mortality.
Results
Results showed uniform conditions across groups 1, 2, and 4. The females in group 3, five days before harvest, exhibited a general alteration, with a decrease in pro-phenol-oxidase content, while coagulation time and phenol-oxidase activity increased. Two berried females in group 3 died before the eggs hatched.
Discussion.
It was interesting to observe the increase in hemolymph coagulation time during maternal incubation, as there are no references regarding this. The activation of hemocytes and proPO, without apparent differences in contact with non-self material among the groups, suggests that M. americanum females experience a metabolic alteration during maternal incubation that delays coagulation time. If the females do not coagulate, they must contend with bleeding and the introduction of non-self material.