Fonte e efeitos dos microrganismos contaminantes em ovos de Podocnemis expansa e P. unifilis em ambiente natural e cativeiro

Abstract

Chelonian eggs are affected by microorganisms of different origins, which, combined with environmental factors and nest quality, can reduce the hatching rate and the number of hatchlings, and impact the conservation of the species. In addition, pathogenic microorganisms can cause public health problems, since freshwater turtle eggs are delicacies in the Amazon region. Taking into account the importance of this microbiota, the objective was to isolate and identify microorganisms in eggs and possible means of contamination of the environment of eggs of Podocnemis expansa and P. unifilis. Samples of cloacal mucus, eggs, natural nest sand and incubator sand from 26 animals were used, in addition to allometric data from the matrices and characteristics of the nests, from authorized commercial breeding and from the natural environment of a protected beach. Also, an experiment was carried out on the shelf life of P. expansa eggs submitted to four treatments (T1: Sand; T2: Control; T3: Hydrogen peroxide; T4: UV light), for a period of 60 days. A total of 1,045 bacterial colonies were isolated, of which 575 identified belong to 15 genera. The most frequent in P. expansa were Pseudomonas sp. (8.29%), Klebsiella sp. (6.6%) and Citrobacter freundii (5.08%); in P. unifilis were Escherichia coli (10.35%), C. freundii (10.13%), Proteus sp. and Serratia marcescens (5.51%). In the breeding center, E. coli, Shigella sp. and Morganella sp. (2.01%), Proteus vulgaris (1.53%), while in the wild, C. freundii (6.89%), Pseudomonas sp. (4.78%), S. marcescens (4.69%). The diversity of the genera was influenced by species, environment, collection period and type of sample, as well as there was a higher frequency of bacteria in P. expansa, natural environment, eggs and spawning samples, although there was similarity between the enterobacteria identified in both species and environments. Allometric and nest characteristics analysis indicated that egg viability is more related to nest and climatic characteristics, that affect incubation time, than the amount and diversity of bacteria in the cloaca of matrices, in the nests or in the eggs. In terms of shelf life, treatments T1 (Sand) and T4 (UV Light) showed better results regarding contamination by coliforms, mesophiles and Staphylococcus aureus in eggshells, with storage periods from 7 days to 15 days with less contamination, which increased significantly in 30 days, in addition to better egg weight maintenance at T1. More studies about egg viability and disinfection and storage methods adaptable and applicable to chelonian eggs, can subsidize species conservation and public health actions.