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Ompok bimaculatus is a commercially important food fish of Northeast India. For higher production of this species, the molecular mechanisms underlying its reproductive physiology is an important aspect to study. Vegetable oils are rich in ω3 and ω6 fatty acids and fat-soluble vitamins, that enhance reproductive performances. In the present study, O. bimaculatus were first fed with vegetable oil at 3, 5, 7 and 9% in the diet. The best treatment was determined by the analysis of relative fecundity, fertilisation rate, Gonadosomatic Index (GSI) and Hepatosomatic Index (HIS). Comparative transcriptomics analysis of gonadal tissues between control and best treatment was done using Illumina NextSeq500. The bioinformatics analysis by Trinity v2.11.0 and edgeR v3.32.1 identified 36 DEGs related to reproduction, those were later validated by qPCR analysis. The Differentially Expressed Genes (DEGs) revealed, regulation of Hypothalamic—pituitary—gonadal axis (HPG) axis through retinoid signalling pathway, IGF pathway and folliculogenesis pathway, including inhibitory effects of dietary vegetable oil on fish gonadal maturation. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of vitamin E on the reproductive responses and the expression of reproductive genes in butter catfish (Ompok bimaculatus). Diets with different levels of vitamin E supplementation (0, 100, and 150 mg/kg) were provided to groups of fish for 60 days. After rearing for 60 days fish were induced with synthetic hormone, that is, Ovatide to study the breeding performance. Ovatide was administrated intramuscularly at the rate of 0.5 and 0.25 mL/kg of body weight for females and males, respectively, in all the treatments. Breeding performance result shows that supplements of vitamin E positively influenced the GSI%, fertilization rate, fecundity, and hatching rate. To understand the relationship between vitamin E and the breeding performance of the fish at the molecular level, a gene expression study was conducted. This study employed real‐time PCR for the selected genes critical for reproductive function. In the brain, testis, and ovary dietary vitamin E supplementation of 100 mg/kg significantly enhanced the mRNA transcription of FSHR, Brdt, ESR1, 17beta2, and LHR. Hence, it can be said that 100 mg/kg of vitamin E supplementation in the diet during the reproductive period of O. bimaculatus could improve breeding performance and the mRNA expression of reproductive hormone receptor genes in both males and females of O. bimaculatus. [ABSTRACT FROM AUTHOR]

Fish pigmentation study can reveal understandings in dermatological research based on functional genomics. Cultured ornamental fish becomes dull coloured and antityrosinase activity through sesame seed may enhance skin colour, which has not been studied. Botia dario is an indigenous fish, having ornamental and aesthetic value and can be studied as a model for fish pigmentation genetics. In this study, fish specimens were fed with 15% marigold petal meal along with 5, 10 and 15% w/w sesame seed in diet. Pigmentation genes, that is, tyr, tyrp1a, asip1, gnaq, kitlga, mc1r, mitf, pax7a, rab38, slc7a11, sox9a, sox10, csf1r, bcdo2 and gsta2 in skin and immunogens, that is, il20, nramp, tlr9 and trail in kidney were studied. Gene expression in tissues revealed enhanced pigmentation and immunity as well as the role of tyr, tyrp1a and asip1 in pigmentation. Immunogenes and blood parameters confirmed the best pigmentation diet. Colorimetric analysis also showed the enhancement of pigmentation. Insights from sesame seed and marigold‐induced antityrosinase effects will be applied in aquaculture to develop natural, dietary formulations that will enhance pigmentation in ornamental fish, leading to improved skin colour and market value. [ABSTRACT FROM AUTHOR]

The catfish Ompok bimaculatus (butter catfish) has recently gained importance as an aquaculture candidate species because of its delicious taste, higher nutritional value and market demand. A significant problem in butter catfish aquaculture is its inability to voluntarily spawn in captivity. This experiment was conducted to study the impact of photoperiod on the voluntary spawning of O. bimaculatus in the pre‐spawning season (April) in captivity. A total of 80 broodfish were equally distributed (n = 20; F = 10 and M = 10) into four photoperiod treatments: natural condition (control), 12:12 light:dark (L:D), 15L:9D and 9L:15D were stocked in rectangular tanks, and the experiment was carried out for 45 days. Light intensity was maintained at 1000 lx throughout the study for all treatments, except the control. The fish were fed a commercial diet (40% crude protein and 6% crude lipid) at a rate of 3% of body weight, twice a day, for 45 days. Ovasis™ was used for hormone induction to study induced breeding. Broodfish reared under natural photoperiod (control) did not respond to voluntary captive spawning. A complete voluntary captive spawning response was observed in the 12L:12D broodfish, and partial success was observed in the 15L:9D and 9L:15D broodfish. The fertilization rate, hatching rate and survival were significantly (p < 0.05) higher in the 12L:12D broodfish group than those in the broodfish group. Hence, the photoperiod regime of 12L:12D with 1000 lx light intensity would be ideal for voluntary captive spawning and can be elected for maximum seed production in the pre‐spawning season. The present study showed that photoperiod manipulation and fixed light intensity stimulate advanced gonadal maturation and voluntary captive spawning of butter catfish, which can help seed production throughout the year. [ABSTRACT FROM AUTHOR]

An experiment was designed to evaluate the requirement of dietary protein for Reba carp, Cirrhinus reba fingerlings using semi‐purified diet. Five isocaloric diets were prepared containing 20%, 25%, 30%, 35% and 40% level of protein using casein, gelatin as a major protein source. The experiment was conducted for 105 days in triplicates to evaluate the growth, survival, feed utilization, carcass composition of C. reba. Mean weight gain was highest (p < .05) in T3. Specific growth rate was highest in T3 and lowest in T1. Similarly, significantly (p < .05) highest net fish yield were recorded in T3. No significant difference was recorded in survivability. Feed conversion ratio, protein efficiency ratio, feed conversion efficiency and protein conversion efficiency were significantly (p < .05) higher for T3 compared with other treatments. Highest carcass protein and lipid values were recorded in T3. So, conclusion can be drawn that 30% crude protein is optimum for overall performance. Furthermore, broken‐line analysis for specific growth rate, final biomass and net fish yield indicated that dietary protein level of 28.148 to 28.253% is optimum for the best growth performance of fingerling C. reba. [ABSTRACT FROM AUTHOR]

Phylogenetic tree using mitochondrial genes and nuclear genes have long been used for augmenting biological classification and understanding evolutionary processes in different lineage of life. But a basic question still exists for finding the most suitable gene for constructing robust phylogenetic tree. Much of the controversy appears due to monophyletic, paraphyletic and polyphyletic clade making deviations from original taxonomy. In the present study we report the first complete mitochondrial genome (mitogenome) of queen loach, generated through next-generation sequencing methods. The assembled mitogenome is a 16,492 bp circular DNA, comprising of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. Further in this study we also investigated the suitability of different mitochondrial region for phylogenetic analysis in Cyprinidae and loach group. For this genetic tree were constructed on COI , COII , COIII , 16S rRNA , 12S rRNA , Cyt b , ATPase 6 , D-loop , ND1 , ND2 , ND3 , ND4 , ND5 , and ND6 along with complete mitogenome. The complete mitogenome based phylogenetic tree got inclusive support from available classical taxonomy for these groups. On individual gene basis Cyt b , 12S rRNA , ND2 and ND3 also produced perfect clade at family and subfamily level. For rest of the genes polyphyly were observed for the fishes belonging to same family or subfamily which makes their use questionable for phylogenetic tree construction. Unlabelled Image • We report the first complete mitogenome of Queen loach, Botia dario using next-generation sequencing methods. • Phylogenetics analysis of complete mitogenome of B. dario and some related fish species from the order Cypriniformes. • A study on Cypriniformes based on complete mitogenome and individual mitogenes to find a suitable gene for phylogenetic tree construction. [ABSTRACT FROM AUTHOR]