Effects of live feed manipulation with algal‐derived antimicrobial metabolites on fish larvae microbiome assembly: A molecular‐based assessment

SummaryThe Roseobacter-group species Phaeobacter inhibens produces the antibacterial tropodithietic acid (TDA) and the algaecidal roseobacticides with both compound classes sharing part of the same biosynthetic pathway. The purpose of this study was to investigate the production of roseobacticides more broadly in TDA-producing roseobacters and to compare the effect of producers and non-producers on microalgae. Of 33 roseobacters analyzed, roseobacticide production was a unique feature of TDA-producing P. inhibens, P. gallaeciensis and P. piscinae strains. One TDA-producing Phaeobacter strain, 27-4, was unable to produce roseobacticides, possibly due to a transposable element. TDA-producing Ruegeria mobilis and Pseudovibrio did not produce roseobacticides. Addition of roseobacticide-containing bacterial extracts affected the growth of the microalgae Rhodomonas salina, Thalassiosira pseudonana and Emiliania huxleyi, while growth of Tetraselmis suecica was unaffected. During co-cultivation, growth of E. huxleyi was initially stimulated by the roseobacticide producer DSM 17395, while the subsequent decline in algal cell numbers during senescence was enhanced. Strain 27-4 that does not produce roseobacticides had no effect on algal growth. Both bacterial strains, DSM 17395 and 27-4, grew during co-cultivation presumably utilizing algal exudates. Furthermore, TDA-producing roseobacters have potential as probiotics in marine larviculture and it is promising that the live feed Tetraselmis was unaffected by roseobacticides-containing extracts.Originality-significance statementSome Roseobacter-group bacteria produce the antibacterial compound tropodithetic acid (TDA) and have potential as probiotics in marine aquaculture. However, a few of these strains additionally produce algaecidal compounds, the roseobacticides, which would restrict their use in marine larviculture where algae are used as live feed for fish larvae. We herein found that roseobacticides are limited to TDA-producing Phaeobacter strains and were not biosynthesized by TDA-producers outside this genus. Roseobacticides affected several strains of microalgae, but not the chlorophyte that is used as live feed in the aquaculture industry. Thus, the application of Roseobacter strains as probiotics is not hampered. Furthermore, these results demonstrate how Roseobacter-group strains act as gardeners of microalgae and thereby would be involved in environmental processes on a larger scale.

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Changes in the Microbiome of Mariculture Feed Organisms after Treatment with a Potentially Probiotic Strain of Phaeobacter inhibens

Applied and Environmental Microbiology ◽

10.1128/aem.00499-20 ◽

2020 ◽

Vol 86 (14) ◽

Author(s):

Karen K. Dittmann ◽

Bastian Barker Rasmussen ◽

Jette Melchiorsen ◽

Eva C. Sonnenschein ◽

Lone Gram ◽

...

Keyword(s):

Bacterial Infections ◽

Fish Larvae ◽

Antagonistic Effect ◽

Rrna Gene ◽

Fish Pathogens ◽

Content Type ◽

Live Feed ◽

The Impact ◽

Phaeobacter Inhibens

ABSTRACT The Phaeobacter genus has been explored as probiotics in mariculture as a sustainable strategy for the prevention of bacterial infections. Its antagonistic effect against common fish pathogens is predominantly due to the production of the antibacterial compound tropodithietic acid (TDA), and TDA-producing strains have repeatedly been isolated from mariculture environments. Despite many in vitro trials targeting pathogens, little is known about its impact on host-associated microbiomes in mariculture. Hence, the purpose of this study was to investigate how the addition of a TDA-producing Phaeobacter inhibens strain affects the microbiomes of live feed organisms and fish larvae. We used 16S rRNA gene sequencing to characterize the bacterial diversity associated with live feed microalgae (Tetraselmis suecica), live feed copepod nauplii (Acartia tonsa), and turbot (Scophthalmus maximus) eggs/larvae. The microbial communities were unique to the three organisms investigated, and the addition of the probiotic bacterium had various effects on the diversity and richness of the microbiomes. The structure of the live feed microbiomes was significantly changed, while no effect was seen on the community structure associated with turbot larvae. The changes were seen primarily in particular taxa. The Rhodobacterales order was indigenous to all three microbiomes and decreased in relative abundance when P. inhibens was introduced in the copepod and turbot microbiomes, while it was unaffected in the microalgal microbiome. Altogether, the study demonstrates that the addition of P. inhibens in higher concentrations, as part of a probiotic regime, does not appear to cause major imbalances in the microbiome, but the effects were specific to closely related taxa. IMPORTANCE This work is an essential part of the risk assessment of the application of roseobacters as probiotics in mariculture. It provides insights into the impact of TDA-producing Phaeobacter inhibens on the commensal bacteria related to mariculture live feed and fish larvae. Also, the study provides a sequencing-based characterization of the microbiomes related to mariculture-relevant microalga, copepods, and turbot larvae.

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Interactions between populations of the calanoid copepodAcartia tonsaDana and the harpacticoid copepodTisbe holothuriaeHumes in mixed cultures of live feed for fish larvae

Aquaculture Research ◽

10.1111/are.13581 ◽

2017 ◽

Vol 49 (3) ◽

pp. 1274-1283

Author(s):

Benni W Hansen ◽

Emil Boesen ◽

Ole B Brodnicke ◽

Natasja L Corfixen ◽

Per M Jepsen ◽

...

Keyword(s):

Fish Larvae ◽

Mixed Cultures ◽

Live Feed

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The influence of diet on the microbiota of live-feed rotifers (Brachionus plicatilis) used in commercial fish larviculture

FEMS Microbiology Letters ◽

10.1093/femsle/fnaa020 ◽

2020 ◽

Vol 367 (2) ◽

Cited By ~ 2

Author(s):

Emre Turgay ◽

Terje Marken Steinum ◽

Kamil Mert Eryalçın ◽

Remziye Eda Yardımcı ◽

Süheyla Karataş

Keyword(s):

Brachionus Plicatilis ◽

Fish Larvae ◽

Bacterial Species ◽

Alpha Diversity ◽

Amplicon Sequencing ◽

Rrna Gene ◽

Fish Pathogens ◽

Study Objective ◽

Commercial Fish ◽

Live Feed

ABSTRACT Live-feed is indispensable to commercial fish larviculture. However, high bacterial loads in rotifers could pose a biosecurity risk. While this may be true, live-feed associated bacteria could also be beneficial to fish larvae through improved feed utilization or pathogen inhibition following host microbiota modification. The study objective was to elucidate the largely unexplored microbiota of rotifers propagated on five different diets through bacterial community profiling by 16S rRNA gene amplicon sequencing. Investigated rotifer samples had a median observed alpha-diversity of 338 ± 87 bacterial species. Alpha- and Gamma-Proteobacteria dominated the rotifer microbiota followed by members of classes Flavobacteriia, Cytophagia, Mollicutes, Phycisphaerae and Bacteroidia. Different diets significantly altered the bacterial communities associated with rotifers according to PERMANOVA test results and beta dispersion calculations. A common core rotifer microbiome included 31 bacterial species present in relative abundances over 0.01%. We discuss the functional role of some microbiome members. Our data suggested the presence of several known fish pathogens in stock rotifers. However, we found no evidence for increased loads of these presumptive taxa in propagated live-feed rotifers during this field trial.

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Application of Live Feeds in the Freshwater Ornamental Fish Larvae of Puntius Dorsalis (Jerdon)

Mapana Journal of Sciences ◽

10.12723/mjs.7.1 ◽

2005 ◽

Vol 4 (2) ◽

pp. 1-7

Author(s):

B. Victor ◽

M. Mannar Mannan ◽

M. Maridass ◽

P. Murphy Alexander ◽

J. M. A. P. Arachi

Keyword(s):

Growth Rate ◽

Specific Growth ◽

Fish Larvae ◽

Maximum Growth ◽

Maximum Growth Rate ◽

Ornamental Fish ◽

Mosquito Larvae ◽

Larval Fishes ◽

Live Feed ◽

Live Feeds

Feeding experiment conducted under laboratory conditions, to determine the suitability of live feed for the larvae of ornamental fish Puntius dorsalis, shows the increase of specific growth rate and weight gain when they were fed with mosquito larvae( 3.284 and 8.04%/day),chironomus larvae(3.308 and 6.24%/day),chopped earthworm (2.618 and 4.39%/day). The maximum growth rate,0.614g was observed in mosquito larvae feed followed by chironomus larvae(0.522 g),chopped earthworm(0.411g) and plankton(0.405g). The present study indicates that mosquito larvae could be used as a suitable live feed for feeding Puntius dorsalis larval fishes.

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Live Feeds Used in the Larval Culture of Red Cusk Eel, Genypterus chilensis, Carry High Levels of Antimicrobial-Resistant Bacteria and Antibiotic-Resistance Genes (ARGs)

Animals ◽

10.3390/ani10030505 ◽

2020 ◽

Vol 10 (3) ◽

pp. 505

Author(s):

Luz Hurtado ◽

Claudio D. Miranda ◽

Rodrigo Rojas ◽

Félix A. Godoy ◽

Mark A. Añazco ◽

...

Keyword(s):

Fish Larvae ◽

Larval Growth ◽

Survival Rates ◽

Larval Survival ◽

Resistant Bacteria ◽

Rrna Gene ◽

Live Feed ◽

Multiresistant Bacteria ◽

A Priority ◽

Genypterus Chilensis

The culture of red cusk eel Genypterus chilensis is currently considered a priority for Chilean aquaculture but low larval survival rates have prompted the need for the continuous use of antibacterials. The main aim of this study was to evaluate the role of live feed as a source of antibacterial-resistant bacteria in a commercial culture of G. chilensis. Samples of rotifer and Artemia cultures used as live feed were collected during the larval growth period and culturable bacterial counts were performed using a spread plate method. Rotifer and Artemia cultures exhibited high levels of resistant bacteria (8.03 × 104 to 1.79 × 107 CFU/g and 1.47 × 106 to 3.50 × 108 CFU/g, respectively). Sixty-five florfenicol-resistant isolates were identified as Vibrio (81.5%) and Pseudoalteromonas (15.4%) using 16S rRNA gene sequence analysis. A high incidence of resistance to streptomycin (93.8%), oxytetracycline (89.2%), co-trimoxazole (84.6%), and kanamycin (73.8%) was exhibited by resistant isolates. A high proportion of isolates (76.9%) carried the florfenicol-resistance encoding genes floR and fexA, as well as plasmid DNA (75.0%). The high prevalence of multiresistant bacteria in live feed increases the incidence of the resistant microbiota in reared fish larvae, thus proper monitoring and management strategies for live feed cultures appear to be a priority for preventing future therapy failures in fish larval cultures.

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Planktonic Crustacean Culture—Live Planktonic Crustaceans as Live Feed for Finfish and Shrimps in Aquaculture

Fisheries and Aquaculture ◽

10.1093/oso/9780190865627.003.0014 ◽

2020 ◽

pp. 342-366

Author(s):

Per Meyer Jepsen ◽

Kristian Syberg ◽

Guillaume Drillet ◽

Benni Winding Hansen

Keyword(s):

Environmental Risk ◽

Fish Larvae ◽

Saline Water ◽

Risk Assessments ◽

Planktonic Crustacean ◽

Live Feed ◽

Test Organisms ◽

Planktonic Crustaceans ◽

Inert Diet ◽

Copepod Eggs

The cultivation of planktonic crustaceans as live feed is of paramount importance for the aquaculture and aquarium industries. The use of live cladocerans as feed for freshwater fish is limited to the aquarium industry, whereas Artemia and copepods are used to feed edible marine fish larvae with small mouth gape. Live feed production is expensive and time consuming; therefore, it is only used for fish that cannot be fed an inert diet directly, and only until they are ready for weaning to an inert diet. High-quality planktonic crustacean cultures are furthermore used to conduct environmental risk assessments for hazardous chemicals. Cladocerans are widely used for ecotoxicology testing, but Artemia and copepods are emerging as new model species. The present chapter reviews the culturing procedures of these important planktonic crustaceans: Artemia, cladocerans, and copepods. It discusses their use as live feed and as test organisms for environmental risk assessments. The culturing procedures are categorized into three complexity levels: Extensive, semi-extensive, and intensive. In general, the pros for Artemia and cladocerans are that they are easier to culture than copepods. Copepods are often more difficult in term of culture requirements and feeding. Nevertheless, copepods have the advantage of being in either freshwater or saline water, whereas cladocerans are limited to freshwater and Artemia to seawater. Artemia cysts and copepod eggs have a well-defined protocol for storage and distribution to aquaculture end users. Cladocerans, however, have the potential for the ephippia stage, although this is not well developed. For toxicological testing, three species are used: Artemia franciscana, Daphnia magna, and Acartia tonsa, with Artemia and A. tonsa in seawater testing, D. magna in freshwater testing. The chapter concludes with a comparative analysis of these organisms from use and culturing capability and demonstrates that there are strong similarities and challenges across these taxa.

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First feeding of freshwater fish larvae with live feed versus compound diets: a meta-analysis

Aquaculture International ◽

10.1007/s10499-011-9424-1 ◽

2011 ◽

Vol 19 (6) ◽

pp. 1217-1228 ◽

Cited By ~ 12

Author(s):

J. Sales

Keyword(s):

Freshwater Fish ◽

Fish Larvae ◽

Meta Analysis ◽

Versus Compound ◽

Live Feed ◽

First Feeding

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PEMELIHARAAN LARVA IKAN KLOWN (Amphiprion percula) DENGAN PAKAN ALAMI YANG BERBEDA

Jurnal Riset Akuakultur ◽

10.15578/jra.11.1.2016.67-73 ◽

2016 ◽

Vol 11 (1) ◽

pp. 67 ◽

Cited By ~ 1

Author(s):

Ketut Maha Setiawati ◽

Gunawan Gunawan ◽

Jhon Harianto Hutapea

Keyword(s):

Body Weight ◽

Fresh Water ◽

Sea Water ◽

Fish Larvae ◽

Ornamental Fish ◽

Rate Performance ◽

Fiber Volume ◽

Amphiprion Percula ◽

Live Feed ◽

Vitality Test

Nilai jual ikan hias klown sangat tergantung dari kecerahan dan keunikan warna yang dimilikinya, namun ikan hias produk hatcheri masih belum sebaik hasil tangkapan alam. Pengkayaan dengan bahan komersial dan Nannochloropsis sp. pada rotifer dan Artemia sebagai pakan alami tidak mampu meningkatkan kecerahan warna benih ikan. Oleh sebab itu, diperlukan pakan alami lain yang mampu meningkatkan kecerahan warna. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian rotifer dan copepod terhadap performan warna benih ikan klown, serta pertumbuhan dan sintasan yang dihasilkan. Penelitian dilakukan dengan menggunakan wadah bak fiber volume 200 L yang diisi air laut sebanyak 150 L. Telur ikan klown yang telah berumur enam hari ditebar sebanyak 200 butir/bak. Perlakuan berupa pemberian pakan alami: (A) rotifer dan (B) rotifer + copepod yang masing-masing mempunyai lima ulangan. Pemberian pakan perlakuan dilakukan sampai larva berumur 30 hari. Selain pakan perlakuan, mulai hari ke-20 juga ditambahkan pakan buatan berupa pakan mikro pada semua larva. Hasil penelitian menunjukkan bahwa, tambahan copepod sebagai pakan alami pada pemeliharaan larva ikan klown dapat meningkatkan kecerahan warna. Selain itu, panjang total dan bobot badan larva pada hari ke-20 untuk perlakuan B adalah masingmasing 10,44 ± 0,24 mm dan 15,2 ± 0,5 mg lebih baik daripada perlakuan A yaitu 9,15 ± 1,27 mm dan 9,2 ± 0,1 mg. Demikian pula vitalitas benih yang dihasilkan, menunjukkan bahwa ikan pada perlakuan B lebih kuat dibandingkan perlakuan A. Benih ikan pada perlakuan B tahan selama 231,6 detik dalam air tawar sedangkan pada perlakuan A hanya selama 39,8 detik.Price of ornamental fish highly depends on the brightness and unique appearance of its color. While of ornamental fish bred in hatcheries are less attractive in appearance compared to the wild ones. Enrichment of live feed i.e rotifer and Artemia using commercial enrichment and Nannochloropsis sp. was not able to improve the color brightness on the hatchery produced seed. Therefore, this research was designed to evaluate the use of other live feed such as copepod to improve color brightness, growth, survival rate, performance, and vitality of clownfish. Larvae used for this research were reared until day 30. The research was conducted using fiberglass tank of 200 L volume and filled with 150 L sea water. Six days eggs were used in the experiment. Eggs density was 200 ind./tank. Larvae were fed either rotifer (A) or rotifer + copepod (B) as treatment. Each treatment has five replicates. The results showed that total length and body weight of larvae in each treatment were 9.15 ± 1.27mm and 9.2 ± 0.1 mg for treatment A, and 10.44 ± 0.24 mm and 15.2 ± 0.5 mg for treatment B. Visually, seed of treatment B had brighter color than treatment A. Vitality test was performed by dipping the seed in fresh water. It showed that seed of treatment B survived for 231.6 seconds, which was longer compared to treatment A which was only survived for 39.8 seconds in fresh water. It can be concluded that addition of copepod as live food for clown fish larvae enhance its growth, color brightness and vitality.

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