Identification of molecular markers in Labeo rohita towards better carbohydrate utilization

The contribution of aquaculture products in providing nutritional and food security to human is increasing expeditiously with the increase in animal protein demand. Feed cost contributes more than 60% of the cost of aquaculture production. Henceforth, formulation of cheap fish feed is one of the greatest challenges in aquaculture industry. Carbohydrates are the cheap source of dietary energy. So their level of utilization in fish is an exciting area in research for decreasing the fish feed cost.  Molecular markers such as microsatellite and single nucleotide polymorphism (SNP) are used for genetic mapping, quantitative trait loci identification and genome-wide association studies in several aquaculture species. In this experiment, SNPs and microsatellite markers linked to carbohydrate utilization in Labeo rohita were identified. Liver tissue samples of Labeo rohita and Labeo bata were collected from individuals fed with a customized diet with 40% carbohydrate for a period of 21 days. RNA was extracted and cDNA library was prepared and sequenced on Illumina NextSeq 500 platform. 7.5 GB of data was generated from each species. Assembly of rohu data resulted in 70, 225 contigs, out of which 6284 microsatellite markers were identified. Among which, 3838, 1817, 488, 132 and 9 were di-, tri-, tetra-, penta- and hexa-repeats, respectively. Primer modelling was successful for 4190 sequences. Similarly, 2, 14, 071 SNPs were identified using CLC bio v7.0.4 and utilizing Illumina reads obtained from Labeo bata. This study can be helpful in efficient use of carbohydrate in Labeo species for decreasing feed cost globally

Complete mitochondrial genome of nearly threatened freshwater ornamental fish, Microphis deocata and its phylogenetic relationship within Syngnathidae

Microphis deocata (deocata pipefish), belonging to family Syngnathidae, is one of the important indigenous ornamental fish species listed as near threatened in the IUCN red list. Here, we first report the complete mitochondrial genome of deocata pipefish using Illumina next-generation sequencing platform. The total length of the mitogenome is 16,526 bp. It encompasses 13 protein coding genes, 2 ribosomal rRNAs, and 22 tRNAs. The WANCY region (a cluster of five tRNA genes) contains the 50 bp OL light strand origin of replication. Phylogenetic analysis of Syngnathidae revealed M. deocata to cluster with Oostethus manadensis, forming a sister group with Doryrhamphus japonicas and Dunckerocampus dactyliophorus. The mitochondrial genome sequence data generated in the present study will play an important role in population genetic analysis and developing conservation strategies for this species

The complete mitochondrial genome of Labeo catla (Hamilton, 1822) using long read sequencing

Labeo catla is a widely cultured species in monoculture and polyculture systems of the Indian subcontinent. In this study, the complete mitochondrial genome sequence of catla was reconstructed from Oxford Nanopore sequence data. The mitochondrial genome is 16,600 bp in length (accession no. is MN830943) which is larger than the previously reported catla mitogenomes. Like other vertebrate mitochondrial genomes, it has 13 protein-coding genes, 22 tRNAs, 2 rRNAs and a putative control region. Most of the mitogenes are encoded on H-strand. Phylogenetic analysis showed that Labeo catla is more closely related to Labeo rohita than other labeo species. The catla mtgenome reported here will facilitate population genetics, phylogenetics and molecular taxonomy of Indian major carps