In the present work the nonapeptides i.e., isotocin and vasotocin alone or in a combination were tested in C. magur to evaluate their effect on stripping by abdominal massage. Also, we used chitosan-carbon nanotube nanocomposites to conjugate the nonapetides isotocin (abbreviated as COOH-SWCNTCSPeP) and isotocin and vasotocin (COOH-SWCNTCSPePs) with the aim of sustaining the effect for a longer duration. The conjugation of nonapeptides with nanocomposites was confirmed by Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Two experiments were conducted to study the effect of naked (without nanoparticles) and conjugated nonapeptides on the milt release by stripping. Both the experiments consisted of eight treatments which included four naked groups two nanoconjugated groups and two controls. Both naked and nonconjugated formulations were successful in stripping the male catfish. The mRNA expression of selected reproductive genes was analysed to decipher the effect of nanopeptides at the molecular level. Nonapeptide treatment either naked or nanoconjugated, resulted in the upregulation of the transcript level of genes. Histological analysis revealed the concentration of spermatozoa was more in peptide injected groups than in the controls. The synergistic effects of nonapeptides and Ovatide had a positive impact on GSI. Thus, the present formulations were successful in stripping the male catfish to obtain the milt with significant reproductive success. Even though the naked groups perform better but the number of males required to fertilize the eggs in nanoconjuagted groups was smaller making it worth using for the delivery of nonapeptides.

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Genetically uniform strains/inbred strains of animals are used in experiments that demand minimal genetic background variability and highly reproducible results. Modern genomic research is heavily dependent on inbred strains and they are widely used for identification of quantitative loci that affect evolutionarily and biomedically important traits, dissection of gene-gene and gene environmental interaction patterns, toxicity studies, immunology, reverse genetics, cancer research, etc. In mice, over 450 inbred strains have been described and in medaka over 13 inbred strains have been established. Owing to its numerous attributes zebrafish, Danio rerio, is one of the widely studied vertebrate model organisms, but comparable zebrafish inbred strains are not available to the scientific community. This is because of early onset of inbreeding depression causing high mortality of embryos and larvae and biased sex ratio that have been reported from earlier attempts to produce inbred lines. At CZeBraG-Centre for Zebrafish Breeding and Genetics Research facility of ICARCIFE, the inbred lines of zebrafish are being developed. The strategy followed is intense inbreeding coupled with strong positive selection for selected traits. The base population consisted of three wild stocks of zebrafish collected from rivers of North East India. Using nested mating design 84 families were produced in F1 generation and 46 inbred families were produced in F2 generation. Genetic parameters for growth traits like body weight and standard length were estimated. The overall heritability for body weight and standard length was estimated using animal model and found to be 0.43 ± 0.05 and 0.36 ± 0.04 respectively. Fecundity was also recorded but showed no significant variation among stocks. Inbreeding depression was studied by comparing the population means for body weight and standard length of F1 and F2 generation. The analysis suggested there was no inbreeding depression. Genetic monitoring of zebrafish is conducted using microsatellite markers. New PCR primers were designed for 20 selected microsatellite loci with high stringency. High Resolution Melting Curve analysis was used for genotyping individual zebrafish. In addition to developing inbred lines the centre is also maintaining the wild zebrafish stocks and has commenced supply of pedigreed zebrafish for researchers. In future zebrafish of known inbred levels (12.5 to 50% and above) can be supplied. Currently, the CZeBraG can house about 10000 adults, with separate facility for holding individual fish.

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