Combining probiotic Phaeobacter inhibens DSM17395 and broad-host-range vibriophage KVP40 against fish pathogenic vibrios

Bastian Barker Rasmussen, Panos G. Kalatzis, Mathias Middelboe, Lone Gram*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Opportunistic pathogenic bacteria readily proliferate in live feed cultures used to feed marine fin fish larvae. As a consequence, larvae cultures fed infected live feed can suffer devastating larvae mortalities. Antibiotics are still used to control these pathogenic bacteria, but due to the risk of antibiotic resistance, sustainable alternatives are required. Phage therapy and probiotic bacteria are examples of alternatives which are currently being developed. However, regrowth of phage tolerant bacteria or reduced inhibition by probiotic bacteria in non-axenic systems, have been seen. The purpose of this study was to investigate if combining the broad-host-range vibriophage KVP40 and probiotic bacteria Phaeobacter inhibens DSM17395 would result in an enhanced inhibitory effect against the fish pathogenic Vibrio anguillarum and protection of live feed and cell lines. The combined and individual treatments were tested in non-axenic live feed systems (i.e. Tetraselmis suecica microalgae and Artemia salina brine shrimps) obtained from a commercial larval rearing unit. Further, we determined if the probiont and/or phages could protect CHSE-214 fish cell line challenged with V. anguillarum. P. inhibens, KVP40 and their combination reduced vibrio counts in the T. suecica cultures with one to two orders of magnitude below inoculum level. Combining KVP40 and P. inhibens resulted in a lower level of V. anguillarum than using the probiont alone. In the Artemia cultures, P. inhibens alone or in combination with KVP40 reduced vibrio counts and Artemia mortality relative to the control, while KVP40 alone only delayed vibrio growth and Artemia mortality. Combining KVP40 and P. inhibens caused an immediate killing of V. anguillarum, however, it did not provide extra inhibitory potential and only little extra protection of Artemia, as compared to using only P. inhibens. Our results demonstrate that probiotic bacteria and phages in commercial, non-axenic live feed can reduce levels of fish pathogenic Vibrio. The combinations of phage and probiont only resulted in a marginal improved pathogen reduction, however, this could and should be further optimized.
Original languageEnglish
Article number734415
JournalAquaculture
Volume513
Number of pages7
ISSN0044-8486
DOIs
Publication statusPublished - 2019

Keywords

  • Roseobacter
  • Phaeobacter
  • Probiotics
  • Phage therapy
  • Vibrio
  • Live feed

Cite this

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title = "Combining probiotic Phaeobacter inhibens DSM17395 and broad-host-range vibriophage KVP40 against fish pathogenic vibrios",
abstract = "Opportunistic pathogenic bacteria readily proliferate in live feed cultures used to feed marine fin fish larvae. As a consequence, larvae cultures fed infected live feed can suffer devastating larvae mortalities. Antibiotics are still used to control these pathogenic bacteria, but due to the risk of antibiotic resistance, sustainable alternatives are required. Phage therapy and probiotic bacteria are examples of alternatives which are currently being developed. However, regrowth of phage tolerant bacteria or reduced inhibition by probiotic bacteria in non-axenic systems, have been seen. The purpose of this study was to investigate if combining the broad-host-range vibriophage KVP40 and probiotic bacteria Phaeobacter inhibens DSM17395 would result in an enhanced inhibitory effect against the fish pathogenic Vibrio anguillarum and protection of live feed and cell lines. The combined and individual treatments were tested in non-axenic live feed systems (i.e. Tetraselmis suecica microalgae and Artemia salina brine shrimps) obtained from a commercial larval rearing unit. Further, we determined if the probiont and/or phages could protect CHSE-214 fish cell line challenged with V. anguillarum. P. inhibens, KVP40 and their combination reduced vibrio counts in the T. suecica cultures with one to two orders of magnitude below inoculum level. Combining KVP40 and P. inhibens resulted in a lower level of V. anguillarum than using the probiont alone. In the Artemia cultures, P. inhibens alone or in combination with KVP40 reduced vibrio counts and Artemia mortality relative to the control, while KVP40 alone only delayed vibrio growth and Artemia mortality. Combining KVP40 and P. inhibens caused an immediate killing of V. anguillarum, however, it did not provide extra inhibitory potential and only little extra protection of Artemia, as compared to using only P. inhibens. Our results demonstrate that probiotic bacteria and phages in commercial, non-axenic live feed can reduce levels of fish pathogenic Vibrio. The combinations of phage and probiont only resulted in a marginal improved pathogen reduction, however, this could and should be further optimized.",
keywords = "Roseobacter, Phaeobacter, Probiotics, Phage therapy, Vibrio, Live feed",
author = "Rasmussen, {Bastian Barker} and Kalatzis, {Panos G.} and Mathias Middelboe and Lone Gram",
year = "2019",
doi = "10.1016/j.aquaculture.2019.734415",
language = "English",
volume = "513",
journal = "Aquaculture",
issn = "0044-8486",
publisher = "Elsevier",

}

Combining probiotic Phaeobacter inhibens DSM17395 and broad-host-range vibriophage KVP40 against fish pathogenic vibrios. / Rasmussen, Bastian Barker; Kalatzis, Panos G.; Middelboe, Mathias; Gram, Lone.

In: Aquaculture, Vol. 513, 734415, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Combining probiotic Phaeobacter inhibens DSM17395 and broad-host-range vibriophage KVP40 against fish pathogenic vibrios

AU - Rasmussen, Bastian Barker

AU - Kalatzis, Panos G.

AU - Middelboe, Mathias

AU - Gram, Lone

PY - 2019

Y1 - 2019

N2 - Opportunistic pathogenic bacteria readily proliferate in live feed cultures used to feed marine fin fish larvae. As a consequence, larvae cultures fed infected live feed can suffer devastating larvae mortalities. Antibiotics are still used to control these pathogenic bacteria, but due to the risk of antibiotic resistance, sustainable alternatives are required. Phage therapy and probiotic bacteria are examples of alternatives which are currently being developed. However, regrowth of phage tolerant bacteria or reduced inhibition by probiotic bacteria in non-axenic systems, have been seen. The purpose of this study was to investigate if combining the broad-host-range vibriophage KVP40 and probiotic bacteria Phaeobacter inhibens DSM17395 would result in an enhanced inhibitory effect against the fish pathogenic Vibrio anguillarum and protection of live feed and cell lines. The combined and individual treatments were tested in non-axenic live feed systems (i.e. Tetraselmis suecica microalgae and Artemia salina brine shrimps) obtained from a commercial larval rearing unit. Further, we determined if the probiont and/or phages could protect CHSE-214 fish cell line challenged with V. anguillarum. P. inhibens, KVP40 and their combination reduced vibrio counts in the T. suecica cultures with one to two orders of magnitude below inoculum level. Combining KVP40 and P. inhibens resulted in a lower level of V. anguillarum than using the probiont alone. In the Artemia cultures, P. inhibens alone or in combination with KVP40 reduced vibrio counts and Artemia mortality relative to the control, while KVP40 alone only delayed vibrio growth and Artemia mortality. Combining KVP40 and P. inhibens caused an immediate killing of V. anguillarum, however, it did not provide extra inhibitory potential and only little extra protection of Artemia, as compared to using only P. inhibens. Our results demonstrate that probiotic bacteria and phages in commercial, non-axenic live feed can reduce levels of fish pathogenic Vibrio. The combinations of phage and probiont only resulted in a marginal improved pathogen reduction, however, this could and should be further optimized.

AB - Opportunistic pathogenic bacteria readily proliferate in live feed cultures used to feed marine fin fish larvae. As a consequence, larvae cultures fed infected live feed can suffer devastating larvae mortalities. Antibiotics are still used to control these pathogenic bacteria, but due to the risk of antibiotic resistance, sustainable alternatives are required. Phage therapy and probiotic bacteria are examples of alternatives which are currently being developed. However, regrowth of phage tolerant bacteria or reduced inhibition by probiotic bacteria in non-axenic systems, have been seen. The purpose of this study was to investigate if combining the broad-host-range vibriophage KVP40 and probiotic bacteria Phaeobacter inhibens DSM17395 would result in an enhanced inhibitory effect against the fish pathogenic Vibrio anguillarum and protection of live feed and cell lines. The combined and individual treatments were tested in non-axenic live feed systems (i.e. Tetraselmis suecica microalgae and Artemia salina brine shrimps) obtained from a commercial larval rearing unit. Further, we determined if the probiont and/or phages could protect CHSE-214 fish cell line challenged with V. anguillarum. P. inhibens, KVP40 and their combination reduced vibrio counts in the T. suecica cultures with one to two orders of magnitude below inoculum level. Combining KVP40 and P. inhibens resulted in a lower level of V. anguillarum than using the probiont alone. In the Artemia cultures, P. inhibens alone or in combination with KVP40 reduced vibrio counts and Artemia mortality relative to the control, while KVP40 alone only delayed vibrio growth and Artemia mortality. Combining KVP40 and P. inhibens caused an immediate killing of V. anguillarum, however, it did not provide extra inhibitory potential and only little extra protection of Artemia, as compared to using only P. inhibens. Our results demonstrate that probiotic bacteria and phages in commercial, non-axenic live feed can reduce levels of fish pathogenic Vibrio. The combinations of phage and probiont only resulted in a marginal improved pathogen reduction, however, this could and should be further optimized.

KW - Roseobacter

KW - Phaeobacter

KW - Probiotics

KW - Phage therapy

KW - Vibrio

KW - Live feed

U2 - 10.1016/j.aquaculture.2019.734415

DO - 10.1016/j.aquaculture.2019.734415

M3 - Journal article

VL - 513

JO - Aquaculture

JF - Aquaculture

SN - 0044-8486

M1 - 734415

ER -