Effect of Pond Fertilization with Vermicompost and Some Other Manures on the Pathogenic Bacterial Populations of Treated Waters

Abstract

Use of organic fertilizers has become very common in the modern piscicultural practices; vermicompost is a new addition to the list of such fertilizers. The efficacy of vermicompost was better than the other fertilizers both in keeping the hydro-biological parameters of treated waters in favourable ranges as well as in maximizing the fish growth. However, its effect on the pathogenic bacterial profile of treated waters is not known. To accomplish this objective, an experiment was performed in 5.54×6.15 m size ponds stocked with three species of Indian major carps viz. catla (Catla catla Ham.), rohu (Labeo rohita Ham.) and mrigal (Cirrhinus mrigala Ham.) at 30 fish per pond in 3:4:3 ratios, respectively. Six treatments viz. a control without any treatment (T 1), pig manure at 4,000 kg haG 1 yearG 1 (T 2), poultry manure at 6,000 kg haG 1 yearG 1 (T 3), cow dung at 10,000 kg haG 1 yearG 1 (T 4), vermicompost at 10,000 kg haG 1 yearG 1 (T 5) and vermicompost at 15,000 kg haG 1 yearG 1 (T 6) were used to monitor their effect on the pathogenic bacterial populations in the treated pond waters. One fourth doses of fertilizers were applied 15 days prior to the fish stocking and the remaining doses were given at fortnightly intervals; the supplementary feed was given at 2% of the body weight of fishes. The pure culture of bacterial isolates segregated from the pond sediments were identified by primary, secondary and tertiary tests and confirmed for their pathogenicity through in vitro and in vivo tests. Overall, seven gram negative pathogenic bacterial strains (viz. Aeromonas hydrophila, Escherichia coli, Enterobacter aerogens, Pseudomonas fluorescens, Klebsiella oxytoca, Pseudomonas aeruginosa and Shigella sp.) and three gram positive strains (viz. Micrococcus luteus, Staphylococcus aureus and Staphylococcus sp.) were isolated from the pond waters treated with different manures. The in vitro and in vivo tests confirmed the pathogenic nature of these bacteria. The abundances of the heterotrophic pathogenic bacteria were minimal in the pond waters treated with vermicompost at 10,000 kg haG 1 yearG 1 followed by those treated with vermicompost at 15,000 kg haG 1 yearG 1 ; the abundances of pathogenic bacteria were higher in waters treated with other fertilizers including under the control treatment. Under other than these two vermicompost treatments, the abundances of pathogenic bacteria were variable depending upon the bacterium-fertilizer type. On the basis of these results, vermicompost at 10,000 kg haG 1 yearG 1 seemed to be the best among the five organic fertilizer treatments in controlling the abundance of pathogenic bacteria in the treated pond waters.

Next‐generation sequencing reveals significant variations in bacterial compositions across the gastrointestinal tracts of the Indian major carps, rohu ( Labeo rohita ), catla ( Catla catla ) and mrigal ( Cirrhinus cirrhosis )

“…Therefore, further investigation is needed (Chan et al ). Drug‐resistant enteric bacteria have been reported in IMC farming ponds and in hilsa fish ( Tenualosa ilisha ) in Bangladesh, indicating transmission of clinical pathogens to aquatic environments (Godara et al ; Hossain et al ; Foysal et al ). Therefore, in‐vivo pathogenicity assays are required to determine the virulence and pathogenicity of Enterobacteriaceae in IMCs because pathogenic bacteria may occasionally be present in fish guts without having any virulence.…”

Effect of Pond Fertilization with Vermicompost and Some Other Manures on the Growth Performance of Indian Major Carps

“…The known usefulness of vermicompost in agriculture not withstanding (Meena, 2003;Saini et al, 2008aSaini et al, ,b, 2010, its usefulness in aquaculture as an organic manure for augmentation of fish production has not yet been extensively explored and only a few reports on this subject are available where efficacy of vermicompost with other commercial manures in enhancing the fish production has been compared (Deolalikar and Mitra, 2004;Kumar et al, 2007;Chakrabarty et al, 2009;Kaur and Ansal, 2010). Our earlier study revealed higher survival rate of Indian major carps in ponds fertilized with vermicompost over those treated with other manures (Godara et al, 2015a), without adversely affecting the water quality parameters (Godara et al, 2015b). Vermicompost is a product of vermi-biotechnology that is frequently used in agro-ecosystems as organic fertilizer (Saini et al, 2008a(Saini et al, ,b, 2010.…”