Isolation of gut associated bacteria from mangrove crabs collected from different mangrove regions of Tamil Nadu, South east coast of India

Mangrove crabs are mostly herbivorous which consume more amount of leaf litter of various mangrove species and also plays most important role in leaf degradation. Several studies reported that crab harbor bacteria from the environment through water and food. Bacterial species of the gut can influence the health and robustness of the host. The present study aims to isolate and enumerate the bacterial count from the gut of crabs collected from different mangrove environments.  The results shows that maximum bacterial load was recorded in Sesarma brockii crabs gut collected from Pichavaram mangroves and minimum was observed in Metopograpsus maculatus crabs collected from Uppanar estuarine mangrove. In the same way, maximum bacterial load was observed in both water and sediment samples of Pichavaram. Bacteria belonging to the genera Bacillus, Pseudomonas and Aeromonas were found at higher levels in all the different mangrove regions. In conclusion, crabs in the various mangrove environments carry a particular bacterial flora, which reflects their environment. The Pichavaram mangrove ecosystem is endowed with a high bacterial load due to the continuous shedding of foliage into the water and subsequent decomposition than other mangrove environments. SEM results confirm that crowded populations of bacteria were attached to the gut region of the mangrove crabs. Key words: Mangrove crabs, gut microflora, isolation, characterization, sediments.