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Not AvailableA wide range of diploid number of chromosomes and the body size of Channa congeners are useful combination of characters for studying the factors controlling the body size. In this study, the karyological information was superimposed on the evolutionary tree generated by 16S rRNA mitochondrial gene sequences. Here, the metaphase chromosome complements stained with Giemsa, AgNO3 and CMA3 were prepared from six snakehead murrel fish species collected from northeast India. The diploid chromosome numbers and the fundamental arms of C. aurantimaculata (2n = 52, NF = 98), C. gachua (2n = 56, NF = 84), C. marulius (2n = 44, NF = 58), C. orientalis (2n = 52, NF = 74), C. punctata (2n = 32, NF = 60) and C. striata (2n = 40, NF = 48) were calculated by the analysis of metaphase chromosome complements. Both methods of nucleolar organizer region (NOR) localization, silver nitrate and chromomycin A3, revealed NOR pairs of 1, 2, 3, 1, 4 and 3 in C. aurantimaculata, C. gachua, C. marulius, C. orientalis, C. punctata and C. striata, respectively. The subject species showed primitive type of asymmetrical chromosomes, except the C. punctata. The variation in 2n for C. orientalis (2n = 52, 78) and C. gachua (2n = 52, 78, 104) of a complete haploid set indicates the possibility of either ploidy change in C. orientalis and C. gachua, if we consider 2n = 52 or the Robertsonian rearrangements in different populations of these two species. The chromosome evolution tree was constructed on 16S rRNA ML-phylogenetic tree using ChromEvol 1.3. The analysis of chromosome evolution explained the loss or gain of chromosome, duplications or semiduplications mechanism. For time scaling the chromosome evolution, the node age of available 16S rRNA gene of Channa species were estimated, which was also used for estimating the time when chromosomal changes occurred in context of geological time-scaleDepartment of Biotechnology, Government of India, New Delh

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Not AvailableKaryotypic characteristics of Barilius bendelisis from Manipur, northeast India reported here revealed diploid count of 50 chromosomes having a karyotype of 16 metacentric, 14 submetacentric and 20 acrocentric chromosomes with fundamental arm numbers, NF = 80. The results were correlated to the available cytogenetic data and analyses the karyotype variations and chromosomal evolution that occurs in the same species of different geographical locations. No sex chromosomes were observed in the species and the comparative study corroborates the hypothesis of chromosomal evolutionary process like centric inversions were responsible for variation in the karyotypic structure in the species. The present study shows that basic information of chromosome number and morphology analysis, are no longer obsolete and can be used to compare the degree of chromosomal diversity over their geographical range, providing important tools for phylogeographic, evolutionary and taxonomic status besides increasing the existing cytogenetic data of the region.Department of Biotechnology, Government of Indi

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Not AvailableKaryotypic characteristics of Barilius bendelisis from Manipur, northeast India reported here revealed diploid count of 50 chromosomes having a karyotype of 16 metacentric, 14 submetacentric and 20 acrocentric chromosomes with fundamental arm numbers, NF = 80. The results were correlated to the available cytogenetic data and analyses the karyotype variations and chromosomal evolution that occurs in the same species of different geographical locations. No sex chromosomes were observed in the species and the comparative study corroborates the hypothesis of chromosomal evolutionary process like centric inversions were responsible for variation in the karyotypic structure in the species. The present study shows that basic information of chromosome number and morphology analysis, are no longer obsolete and can be used to compare the degree of chromosomal diversity over their geographical range, providing important tools for phylogeographic, evolutionary and taxonomic status besides increasing the existing cytogenetic data of the region.Department of Biotechnology, Government of Indi

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Not AvailableThe Glossogobius giuris (Gobiidae), tank goby a species of goby fish, is native mainly to freshwater and estuaries and has importance in the aquarium trade. It is classified as least concern under IUCN Red List. Live individuals of this species were collected from Loktak Lake in Manipur for cytogenetic investigation to reveal the nucleolar organizer region (NOR) through silver nitrate (AgNO3) and chromomycin A3 (CMA3) staining as well as DAPI staining and single-color fluorescence in situ hybridization (FISH) using 18S rDNA sequence as probe. Analysis of more than 50 metaphase chromosome complement (obtained from colchicine–potassium chloride–Carnoy’s fixation–Giemsa staining procedures) showed the presence of 46 diploid chromosome numbers with all telocentric having fundamental arm number as 46 without any heteromorphic pair. One pairs of silver-stained NORs, situated terminally on the telocentric chromosome, were observed. Similarly, one pair of CMA3-positive sites were observed on the chromosome that suggested abundance of GC-rich repetitive DNAs in this region. One pair of 18S rDNA positive sites was observed on the telocentric chromosomes using FISH. These karyological features can be useful markers in cytotaxonomy and conservation of this species.Department of Biotechnology, Ministry of Science and Technology, Government of India, for financial support through Project Sanction No. BT/13/NE/TBP/201

Stocking density affects immune and stress-related gene expression of Butter catfish (Ompok bimaculatus) fry in biofloc landscapes

Scientific research into fish wellness is critical, and the concerns about crowding-related stress due to increased stocking density are inevitable. Taking this into consideration, the study defines the physiological signature of Ompok bimaculatus (Butter catfish) in a biofloc system when subjected to varying levels of stocking density. Fish (mean weight = 1.21 g ± 0.08, n = 600) were randomly stocked in 40-L glass aquaria at stocking densities of 0.5 g/L (T1), 1 g/L (T2), 1.5 g/L (T3), and 2 g/L (T4) and fed a 35% protein diet. After the 90-day trial, the physio-biochemical, molecular, and tissue-level changes were assessed. An integrated biomarker response (IBR) analysis for the key stress indicators aided us in better understanding them. There was a significant difference in blood count between T1 and T4 (total erythrocyte count, hemoglobin, and packed cell volume). T1 had higher levels of globulin and total plasma protein, but T2 had higher levels of albumin. Only in T1 did the respiratory burst and lysozyme activity appear to be higher (p < 0.05). Increased stocking densities had a significant impact on the liver function enzymes, GOT and GPT (p < 0.05). In comparison to lower densities (T1 &amp; T2), higher stocking density (T3 &amp; T4) was found to raise glucose and cortisol levels (p < 0.05). Antioxidant enzymes such as catalase, glutathione-S-transferase, and malondialdehyde were found to be more pronounced in lower density tissues (T1). Furthermore, the IBR plots show that lower densities have better health than higher densities. At higher stocking densities, mRNA expression of HSP70, IL-1, and IL-20 increased (p < 0.05) in kidney and liver tissues. The Nrf-2 and Tlr-9 genes were also upregulated. Also, when stocking density was increased, tissue-level histo-architectural changes were more pronounced than when stocking density was kept low. The findings of this study show that the welfare of Butter catfish cultured at high density in biofloc systems suffers from severe stress, and therefore draw more attention to the development of a species-specific standard rearing methodology in the pursuit of a profitable aqua-farming enterprise

Effect of Stocking Density on Growth, Water Quality Changes and Cost Efficiency of Butter Catfish (<i>Ompok bimaculatus</i>) during Seed Rearing in a Biofloc System

Biofloc technology is a modern-day high-density fish culture system employing heterotrophic conversion of nitrogenous waste into useful flocs for water quality control and improved welfare. However, optimization of the stocking density for the target species during seed rearing is the key to a successful farming operation. The study evaluated the effect of different stocking density on the growth, feed utilization, digestive physiology and economics in a biofloc-based seed rearing of butter catfish, O. bimaculatus. Advanced fry (1.21 ± 0.08 g) was reared in a zero-water exchange biofloc system for 90 days at stocking densities of 0.5 g/L(T1), 1.0 g/L(T2), 1.5 g/L(T3) and 2.0 g/L(T4). The observed water quality indicates a reduction in DO and pH in T4, while the total ammonia nitrogen and nitrite levels remained low in T1. Among the groups, highest weight gain was noticed in the lowest stocking density (0.5 g/L) (p O. bimaculatus. The study provides direction for a low-stocking oriented ecological and economically sustainable method of seed production of butter catfish in a biofloc system

Effect of Stocking Density on Growth, Water Quality Changes and Cost Efficiency of Butter Catfish (Ompok bimaculatus) during Seed Rearing in a Biofloc System

Biofloc technology is a modern-day high-density fish culture system employing heterotrophic conversion of nitrogenous waste into useful flocs for water quality control and improved welfare. However, optimization of the stocking density for the target species during seed rearing is the key to a successful farming operation. The study evaluated the effect of different stocking density on the growth, feed utilization, digestive physiology and economics in a biofloc-based seed rearing of butter catfish, O. bimaculatus. Advanced fry (1.21 &plusmn; 0.08 g) was reared in a zero-water exchange biofloc system for 90 days at stocking densities of 0.5 g/L(T1), 1.0 g/L(T2), 1.5 g/L(T3) and 2.0 g/L(T4). The observed water quality indicates a reduction in DO and pH in T4, while the total ammonia nitrogen and nitrite levels remained low in T1. Among the groups, highest weight gain was noticed in the lowest stocking density (0.5 g/L) (p &lt; 0.05), which coincides with a better feed conversion ratio. Similarly, the digestive enzyme (protease, amylase, and lipase) secretion was higher in T1. Profitability assessment describes the possibility of low profit in T4, in the case where the fish&rsquo;s sale price is based on harvested size. T1 showed higher individual growth and higher profit. Overall, a low stocking density of 0.5 g/Lis optimum for augmenting growth, feed utilization, physiological function and economic performance of O. bimaculatus. The study provides direction for a low-stocking oriented ecological and economically sustainable method of seed production of butter catfish in a biofloc system