New bacilli-based probiotic for aquaculture: efficacy study on Macrobrachium rosenbergii

The data on the study of the effectiveness of a new probiotic based on strains B. toyonensis B-13249 and B. pumilus B-13250 when growing shrimps are presented. The experiments were carried out on a private farm in Kazakhstan. The control group of shrimps, which did not receive the probiotic, completed the molting process on the 28th day of the experiment, and the experimental group – 10 days earlier. It was also found that the probiotic has a positive effect on the hydrochemistry of water in recirculating aquaculture system (RAS). The concentration of ammonium (NH3/NH4 +), nitrite (NO2) and nitrate (NO3-) nitrogen in the experimental group did not reach the limit value, in contrast to the control. Based on the obtained results, this probiotic can be recommended for greening aquaculture. The dosage of the probiotic when applied with brine shrimp as feed for shrimp is 1 g/100 g of dry cysts. The dosage of the probiotic when the RAS is added to the water is 5 g/600 l of circulating water once a week.

Complete Genome Sequence of Macrobrachium rosenbergii Golda Virus (MrGV) from China

In a meta-transcriptome study of the giant freshwater prawn Macrobrachium rosenbergii sampled in 2018 from a hatchery, we identified a variant of Macrobrachium rosenbergii golda virus (MrGV) in postlarvae without clinical signs. The virus belongs to the family Roniviridae, and the genome of this MrGV variant, Mr-18, consisted of 28,957 nucleotides, including 4 open reading frames (ORFs): (1) ORF1a, encoding a 3C-like protein (3CLP) (4933 aa); (2) ORF1b, encoding a replicase polyprotein (2877 aa); (3) ORF2, encoding a hypothetical nucleocapsid protein (125 aa); and (4) ORF3, encoding a glycoprotein (1503 aa). ORF1a overlaps with ORF1b with 40 nucleotides, where a −1 ribosomal frameshift with slippage sequence 5′-G14925GGUUUU14931-3′ produces the pp1ab polyprotein. The genomic sequence of Mr-18 shared 97.80% identity with MrGV LH1-2018 discovered in Bangladesh. The amino acid sequence identities between them were 99.30% (ORF1a), 99.60% (ORF1b), 100.00% (ORF2), and 99.80% (ORF3), respectively. Phylogenetic analysis of the RNA-dependent RNA polymerase (RdRp) proteins revealed that they clustered together and formed a separate cluster from the genus Okavirus. The finding of MrGV in China warrants further studies to determine its pathogenicity and prevalence within the region.

Sinopse sobre as características dos aspectos técnicos e econômicos no cultivo de camarão de água doce Macrobrachium rosenbergii no Brasil

Este artigo de revisão bibliográfica fornece uma visão geral da criação sustentável de camarãode água doce no Brasil. Este estudo indica que o Macrobrachium rosenbergii pode ser o crustáceo deágua doce mais adequado e economicamente importante para a criação. Embora o Brasil possua vastosrecursos de água doce, eles não são totalmente explorados. O cultivo de camarão de água doce (M.rosenbergii) no Brasil pode desempenhar um papel importante na economia do país, aumentando aprodução de alimentos e oferecendo oportunidades de emprego. O cultivo do camarão de água doce noBrasil tem como objetivo diversificar os produtos utilizados para a aquicultura de água doce,atualmente dominada pela tilápia. Como a criação de camarão requer serviços de apoio à aquiculturadesenvolvidos, deve-se buscar treinamento, pesquisa, extensão, instalações de infraestrutura edesenvolvimento de sistemas de marketing e distribuição.