ISSN: 2577-4050
Authors: González-Gómez G and Okolodkov YB*
Macrobrachium rosenbergii, the main species of the shrimp genus that is traded worldwide, commonly cultivated in China, India and Thailand, was introduced to Mexico in 1973. It is susceptible to infectious diseases associated with high mortality during its eleven larval stages, resulting in severe economic losses. To infer the source of contamination by protozoans during two larval development cycles of the shrimp in the aquaculture farm “Santa Fe” in Santa Fe, Veracruz, Mexico in 2021 was one of the aims of the study. The shrimp larvae (stages I-XI) in vivo, the culture medium and the food (Artemia salina) supplied for the larvae were examined using light microscopy, based on records, albeit rare, where food was contaminated by protozoans. The Hill numbers (N0, N1 and N2), the Shannon-Wiener diversity index, the Simpson’s dominance and the Pielou’s evenness indices were determined. Mortality rate in both cycles was similar: 89% in cycle 1 and 90% in cycle 2. The results showed that the mortality of larvae was not caused by the protozoan contaminants in the culture medium in which ten protozoan (nine freeliving and an epizoic) and two rotifer taxa (Rotaria rotatoria and Keratella sp.) were identified. Taxonomic protozoan diversity was the lowest in the first shrimp larval stages and was higher in the last stages. During the two cycles, Hymenostomatida gen. sp. was the most abundant, and Litostomatea gen. sp. was the least abundant. The results suggested the food (A. salina) as a probable source of contamination of the shrimp culture by protozoans.
Keywords: Artemia; Cultivation; Mexico; Macrobrachium rosenbergii; Protozoans
