The Efficacy of Moina micrura Enriched with Probiotic Bacillus pocheonensis in Enhancing Survival and Disease Resistance of Red Hybrid Tilapia (Oreochromis spp.) Larvae

Abstract

The administration of probiotics via live feeds, such as Artemia and rotifers, has gained significant attention. Moreover, indiscriminate use of antibiotics in conventional aquaculture practices in order to prevent or control disease outbreaks has resulted in the occurrence of residues and antimicrobial resistance. Thus, the application of eco-friendly feed additives, such as probiotics, as a safer alternative has received increasing attention in recent years. However, only minimal information on the administration of probiotics via freshwater cladoceran Moina micrura is available despite being commonly used for larval and post-larval feeding of freshwater crustaceans and fish. Thus, this study aimed to evaluate the application of Bacillus pocheonensis strain S2 administered via M. micrura to red hybrid tilapia (Oreochromis spp.) larvae. Bacillus pocheonensis that has been previously isolated from Spirulina sp. was subjected to preliminary in vitro evaluation of antagonistic properties. The agar well-diffusion assay revealed that this probiont could inhibit the growth of Streptococcus agalactiae and Aeromonas hydrophila. The size of inhibition zones ranged from 8.8 ± 0.2 to 18.2 ± 0.4 mm. Moina micrura was later used as a biological model in preliminary in vivo bacterial challenge assays to evaluate the efficacy of B. pocheonensis in protecting the host from diseases. Moina micrura was pre-enriched with B. pocheonensis at 104 and 106 CFU mL-1 before S. agalactiae and A. hydrophila were introduced into the culture. The study revealed that B. pocheonensis at 104 CFU mL-1 was able to significantly enhance the survival of M. micrura after being challenged with both pathogens (63 ± 3%) in comparison to the control group. The relative percentage survival (RPS) of M. micrura was highest (p < 0.05) when treated with B. pocheonensis at both concentrations 104 and 106 CFU mL-1 (38.33) after being challenged against S. agalactiae. To assess the efficacy of B. pocheonensis in protecting red hybrid tilapia against streptococcosis, the larvae were fed with either unenriched (control) Moina or probiont-enriched Moina daily for 10 days. A significantly (p < 0.05) higher survival rate (77 ± 3%) was observed in larvae fed with probiont-enriched M. micrura compared to other treatments, and the RPS was recorded at 62.90. In addition, the S. agalactiae load was suppressed in larvae fed probiont-enriched M. micrura (6.84 ± 0.39 CFU mL-1) in comparison to the control group (7.78 ± 0.09 CFU mL-1), indicating that the probiont might have contributed to the improvement of tilapia health and survival. This study illustrated that M. micrura was suitable to be used as a vector for probiotics in freshwater fish larvae as an alternative to hazardous antibiotics for disease control.

Enrichment of Artemia sp. with autochthonous probiotics at different levels in larviculture of piauçu Megaleporinus macrocephalus

“…These results may be related to the greatest presence of lactic acid bacteria in the intestines of the animals. Similar results were observed for tilapia larvae supplemented with Bacillus pocheonensis at the concentration of 5 × 10 5 CFU•mL -1 in Moina micrura enrichment, conferring greater larval survival and resistance to Streptococcus agalactiae (Samat et al, 2021). The enrichment of Artemia nauplii with the probiotic Bacillus subtilis and inulin at the concentration of 7 g•L -1 for 12 days also promoted a better gain in length and total height of Pseudoplatystoma reticulatum larvae (Oliveira et al, 2022).…”

“…In the case of fish larvae, the introduction of probiotics by enriched live foods is an alternative (Ghorbani Vaghei et al, 2019;Ghoname et al, 2020;Oliveira et al, 2022) as it assists in the development of the intestine, balancing the microbiota (Comabella et al, 2013;Stephens et al, 2016), immune system development, and in the synthesis and absorption of amino acids and nutrients from the diet (Chung et al, 2012;Arrieta et al, 2014). Thus, in the larviculture of aquatic organisms, studies with bioencapsulated probiotics in live diets, such as artemia and rotifers, have promising results in aquaculture (Sun et al, 2013;Bhaheerathan et al, 2020;Ghoname et al, 2020;Samat et al, 2021;Oliveira et al, 2022).…”

Effects of temperature, pH, and photoperiod on the performance of a freshwater cladoceran Moina micrura culture enriched with Lysinibacillus fusiformis and Bacillus pocheonensis

“…In previous studies, L. fusiformis A1 and B. pocheonensis S2 displayed strong antibacterial activity against two marine pathogens, mainly Vibrio harveyi and Vibrio parahaemolyticus (Rosland et al 2021), and two freshwater pathogens, including Aeromonas hydrophila and Streptococcus agalactiae (Samat et al 2021). Thus, the present study aimed to evaluate the potential of these strains in aiding M. micrura performance at different levels of environmental parameters.…”

Molecular farming: Expanding the field of edible vaccines for sustainable fish aquaculture

“…[53][54][55][56][57][58] Additionally, due to their encapsulating capacities, they have been previously used for oral delivery of various probiotic strains, resulting in improved health, overall growth, and fitness of different fish species. [59][60][61] However, despite the encapsulation abilities of other species, delivery of specific antigens is facilitated mainly by Artemia.…”

“…Owing to their capacity to naturally consume bacteria, yeasts, or microalgae, these crustaceans are commonly used as carriers for nutritional or antibacterial agents 53–58 . Additionally, due to their encapsulating capacities, they have been previously used for oral delivery of various probiotic strains, resulting in improved health, overall growth, and fitness of different fish species 59–61 . However, despite the encapsulation abilities of other species, delivery of specific antigens is facilitated mainly by Artemia .…”