Unveiling population structure and selection signatures of riverine and genetically improved rohu, Labeo rohita using genome wide SNPs.

BACKGROUND: Captive breeding, along with artificial selection can significantly impact population structure by influencing allele frequencies and driving populations towards specific adaptation. Selective sweeps are powerful forces in shaping genetic variation within populations and can drive rapid spread of beneficial alleles while simultaneously reducing genetic diversity in localized regions of the genome. The present work was undertaken to assess the genetic structure and consequences of artificial selection in 10th generation of genetically improved rohu by comparing with wild populations. METHODS AND RESULTS: The present study used 11,022 high-quality genome wide SNPs to compare the population genetic structure and signatures of selection between Jayanti rohu population and its wild counterpart. Outlier analysis revealed presence of 14 adaptive SNPs, out of which 5 were classified to be under decisive selection pressure. Notably, Jayanti rohu (JR) displayed 297 private alleles exclusive to its population. Chromosomes 7 and 16 emerged as potential hotspots containing a majority of the identified SNPs. Structure and principal component analysis revealed two distinct clusters, effectively distinguishing the JR and wild rohu populations. Phylogenetic analysis indicated a separate cluster of JR population distant from wild groups. CONCLUSION: The results of present study shall help in elucidating patterns of genetic variation and characterizing selection signatures associated with captive bred and natural populations of rohu. The genomic resources generated through this work shall be helpful in improving the traceability of selectively bred germplasm for developing future strategies of genetic management.

Xylooligosaccharide supplementation in rice protein concentrate based diets: A comprehensive analysis of performance and health of Labeo rohita.

The primary aim of this study was to examine the impact of xylooligosaccharide (XOS) in rice protein concentrate (RPC) based diets on the growth performance, body composition, digestive enzymes, intestinal morphology and blood biochemistry of Labeo rohita fingerlings. Four different XOS levels (0%, 0.5%, 1% and 2%) were used at each RPC (75% and 100%) level. Twenty-five fish per tank with an average initial weight of 25 ± 0.05 g were randomly assigned (Randomised complete block design) to each of the 8 groups in triplicate aquaria (36 × 16 × 12″) and then fed with respective diets @ 3% body weight for 90 days. The results showed significant improvements in growth performance, such as increased weight gain %, specific growth rate, and protein efficiency ratio and improved feed conversion ratio in 1% XOS supplemented diet at 75% RPC. A significant decrease in serum alkaline phosphatase activity (ALP) and plasma melanodialdehyde (MDA) were observed at 1% XOS level in 75% RPC based diets, respectively. Meanwhile, the lowest total cholesterol and highest lysozyme activity were observed in 1% XOS supplemented diet at 75% RPC levels. Moreover, the serum (alanine aminotransferase and aspartate transaminase) and plasma (superoxide dismutase, triglyceride, high density and low density lipoprotein) activities showed nonsignificant effects among the treatments. Furthermore, the digestive enzymes (protease & lipase) and intestinal morphology were significantly influenced at 1% XOS in the 75% RPC-based diet. Polynomial regression analysis showed that 1.25% XOS is the optimum requirement for the growth of rohu fingerlings when fed at 75% RPC based diets. Overall, it was concluded that the 75% RPC diet was efficiently replaced by fishmeal along with 1% XOS addition in L. rohita fingerlings without any negative effect on growth performance and intestinal health.

Diffusion of organochlorine (OCPs) and cypermethrin pesticides from rohu (Labeo rohita) internal organs to edible tissues during ice storage: a threat to human health.

The migration of organochlorine pesticides (OCPs) and cypermethrin residues from internal organs to edible tissues of ice-held Labeo rohita (rohu) was investigated in this study. The liver (246 µg/kg) had the highest level of ∑OCP residues, followed by the gills (226 µg/kg), intestine (167 µg/kg), and muscle tissue (54 µg/kg). The predominant OCPs in the liver and gut were endosulfan (53-66 µg/kg), endrin (45-53 µg/kg), and dichloro-diphenyl-trichloroethane (DDT; 26-35 µg/kg). The ∑OCP residues in muscle increased to 152 µg/kg when the entire rohu was stored in ice, but they decreased to 129 µg/kg in gill tissues. On days 5 and 9, the total OCPs in the liver increased to 317 µg/kg and 933 µg/kg, respectively. Beyond day 5 of storage, total internal organ disintegration had led to an abnormal increase in OCP residues of liver-like mass. Despite a threefold increase in overall OCP residues by day 9, accumulation of benzene hexachloride (BHC) and heptachlor was sixfold, endrin and DDT were fourfold, aldrin was threefold, and endosulfan and cypermethrin were both twofold. Endosulfan, DDT, endrin, and heptachlor were similarly lost in the gills at a rate of 40%, while aldrin and BHC were also lost at 60 and 30%, respectively. The accumulation of OCP residues in tissues has been attributed to particular types of fatty acid derivatives. The study concluded that while pesticide diffusion to edible tissues can occur during ice storage, the levels observed were well below the allowable limit for endosulfan, endrin, and DDT.

Impact of antioxidant potential of rohu (Labeo rohita) swim bladder gelatin hydrolysate on oxidative stability, textural and sensory properties of fish sausage enriched with polyunsaturated fatty acids.

The impact of rohu swim bladder gelatin hydrolysate (SBGH) at different levels on textural, sensory, oxidative, and microbial properties of polyunsaturated fatty acids enriched rohu fish cooked sausages (PUFA-RFS) were investigated in the current study. SBGH addition enhanced the lightness values of PUFA-RFS compared to both control sausages (without SBGH and with butylated hydroxyanisole (BHA) (P > 0.05). PUFA-RFS added with 3% SBGH exhibited higher hardness, cohesiveness, and gumminess throughout the storage duration at both 4 °C and -20 °C temperatures when compared to other sausages counterparts. PUFA-RFS added with SBGH displayed lower PV, TBARS, and total microbial counts than the control sausages. Furthermore, PV, TBARS, and total microbial count values of sausage decreased with an increase in SBGH level, indicating retardation in lipid oxidation and microbial growth by SBGH in a dose-depended manner. Nevertheless, sausage added with 3% SBGH had higher overall acceptability than other sausage counterparts. Therefore, SBGH could retard lipid oxidation and improves textural properties of PUFA-enriched fish sausage.

Biofunctional components and bacterial dynamics of enzymatic and fermentatively prepared rohu (Labeo rohita) egg sauce.

The present study focused on preparing rohu egg sauce using optimized conditions through enzymatic and fermentative methods. The enzymatic preparation of rohu egg sauce (ERS) involved homogenizing the eggs in water at a ratio of 1:0.9 (w/v), followed by the addition of salt (20% w/w) and papain (3% w/w). A mixture containing salt (25% w/w), sugar (7.5% w/w), and inoculum (10% (w/v)) of Pediococcus pentosaceus FSBP4-40 was utilized to prepare fermentatively produced rohu egg sauce (FRS). ERS and FRS were then stored at room temperature (25 ± 2 °C) and 37 °C for 180 days. After storage, both sauces were evaluated for their scavenging activity against DPPH, ABTS, and superoxide anion (SOA). The ERS demonstrated significantly higher DPPH, ABTS, and SOA scavenging activity compared to the FRS, with values of 61.61 ± 7.33%, 71.21 ± 2.14%, and 85.11 ± 4.92%, respectively, as opposed to 37.49 ± 5.34, 52.31 ± 1.76%, and 63.09 ± 2.31%. Significant changes were observed in the fatty acid profile of the sauces during 180 day storage. Furthermore, after 180 days, the bacterial counts in the FRS were much lower than in the ERS. Overall, this study highlights the importance of using enzymes and LAB in accelerating the hydrolytic process to produce biofunctional rohu egg sauce.

Evaluation of carboxylated poly-l-lysine for cryopreservation of Labeo rohita sperm.

Carboxylated poly-l-lysine (CPLL) is an anti-freeze agent having pronounced non-permeating yet membrane stabilizing cryoprotective capabilities. The objective was to evaluate the CPLL supplementation in extender in terms of post-thaw quality (sperm), total anti-oxidant activity (milt) and fertilization potential of cryopreserved Labeo rohita sperm. For this purpose, male brood fish reared at a fish seed hatchery, Rawal Town Islamabad, Pakistan were captured from different rearing ponds and acclimatized in hatchery ponds for 6 h. The brooder was injected with Ovaprim (0.2 mL/kg), and milt was collected after 8 h in cooled sterilized falcon tubes, maintained at 4°C and evaluated for sperm motility. The milt collected from three brooders (n = 3) was diluted in extenders viz., modified Kurokura-2 extender having 10% methanol (control); experimental extenders with CPLL supplementation at the rate of 0.5%, 1% and 1.5%. Diluted milt was filled in 0.5 mL straws, exposed to liquid nitrogen vapours and cryopreserved. Cryopreserved milt was thawed at 25°C and assessed for post-thaw sperm quality. Sperm motility, motility duration, viability, total anti-oxidant capacity and DNA integrity was significantly higher (p < 0.05) in the extender having 1.5% CPLL than control. To evaluate the fertilization rates, male and female brooders were injected with Ovaprim at 0.2 mL/Kg and 0.5 mL/Kg body weight respectively. Fresh eggs and milt were collected through abdominal stripping. Batches of 10 g of eggs from each female (n = 2) were fertilized with one straw, each from frozen sperm with KE + methanol (control), KE + methanol + 1.5% CPLL and 50 µL fresh milt (negative control). After 1.5 h of fertilization, eggs were collected from all jars and a total of 200 eggs were counted. The fertilized eggs appeared clear and transparent while unfertilized eggs looked opaque with disintegrated nuclei. Sperm fertilization rate (%) was higher (p < 0.05) in extender KE + methanol + 1.5% CPLL (78.7 ± 0.5) compared to control (KE + methanol) (52.0 ± 0.4) however, it was lower compared to that of negative control, the fresh milt (85.2 ± 0.6). In conclusion, supplementation of carboxylated poly-l-lysine (1.5%) to modified Kurokura-2 extender having 10% methanol improves post-thaw motility, motility duration, viability, DNA integrity, anti-oxidant capacity (milt) and fertilizing ability of cryopreserved L. rohita sperm.

Organ-Based Proteome and Post-Translational Modification Profiling of a Widely Cultivated Tropical Water Fish, Labeo rohita.

Proteomics has enormous applications in human and animal research. However, proteomic studies in fisheries science are quite scanty particularly for economically important species. Few proteomic studies have been carried out in model fish species, but comprehensive proteomics of aquaculture species are still scarce. This study aimed to perform a comprehensive organ-based protein profiling of important tissue samples for one of the most important aquaculture species,Labeo rohita.Deep proteomic profiling of 17 histologically normal tissues, blood plasma, and embryo provided mass-spectrometric evidence for 8498 proteins at 1% false discovery rate that make up about 26% of the total annotated protein-coding sequences in Rohu. Tissue-wise expression analysis was performed, and the presence of several biologically important proteins was also verified using a targeted proteomic approach. We identified the global post-translational modifications (PTMs) in terms of acetylation (N-terminus and lysine), methylation (N-terminus, lysine, and arginine), and phosphorylation (serine, threonine, and tyrosine) to present a comprehensive proteome resource. An interactive web-based portal has been developed for an overall landscape of protein expression across the studied tissues of Labeo rohita (www.fishprot.org). This draft proteome map of Labeo rohita would advance basic and applied research in aquaculture to meet the most critical challenge of providing food and nutritional security to an increasing world population.

Utilization of protein isolates from rohu (Labeo rohita) processing waste through incorporation into fish sausages; quality evaluation of the resultant paste and end product.

BACKGROUND: Fish processing waste could be valorized by recuperating the nutrients for human consumption. Employing a suitable process would address the pollution problems associated with its dumping and would contribute to food security. In this study, protein isolates obtained from rohu (Labeo rohita) processing waste through the pH shift process (pH 13.0) were valorized through incorporation into pangasius (Pangasius pangasius) mince sausages (0.0, 50, 100, 250, and 500 g kg-1 ). These sausages were analyzed for their proximate composition, and their physical and eating quality. RESULTS: Increasing the isolate content (11.57% to 16.14%) in sausages increased their protein content and whiteness values (P < 0.05). At 250 g kg-1 level, the cooking yield was maximum, and the expressible fluid content of paste was minimum. Moreover, adding rohu protein isolates in pangasius mince increased the expressible moisture and decreased its folding and gel strength values (P < 0.05). The gel strength values were highest for the sausages without isolates (2648.67 g cm). In contrast, in the sausages containing 250, 100, and 500 g kg-1 isolate, the values were determined to be 847.88, 731.21, and 611.06 g cm, respectively. Replacing pangasius mince with rohu protein isolates had a non-significant effect on the sensory attributes of the sausages. CONCLUSION: Replacing pangasius mince with rohu protein isolates at 250 g kg-1 resulted in superior quality sausages compared with other levels tested. Incorporating rohu protein isolates in fish sausages improved the nutritional value without significantly reducing their eating quality. The findings of this study indicate promising potential for developing nutrient-rich foods using fish protein isolates. © 2021 Society of Chemical Industry.

Efficacy of ulvan on immune response and immuno-antioxidant gene modulation in Labeo rohita against columnaris disease.

This study reports the effect of ulvan enriched diet on the influence of growth, changes in hemato-biochemical indices, improvement of antioxidant system, enhancement of innate-adaptive immunity and modification of immuno-antioxidant genes expression in Labeo rohita against Flavobacterium columnaris. The weight gain (WG) was significantly high (P > 0.05) in unchallenged normal and challenged fish fed with diets enriched with 25 and 50 mg kg-1 ulvan; the FCR was better (P > 0.05) when fed with 50 mg kg-1 enriched diet. In normal fish fed with or without ulvan supplementation was noted 100% survival rate (SR). In both groups, the red blood cell (RBC) and while blood cell (WBC) counts increased significantly (P > 0.05) when fed with 50 mg kg-1 ulvan diet whereas the hemoglobin (Hb) level increased significantly on being fed with 25 and 50 mg kg-1 ulvan diets. The SOD activity was enhanced significantly in both groups fed with any dose of ulvan diets whereas the MDA and GPx activity increased only with 25 and 50 mg kg-1 ulvan diets. The phagocytic (PC) activity significantly increased with any enriched diet and control diet groups while the respiratory burst (RB) activity increased only with 50 mg kg-1 ulvan diet. The alternate complement pathway (ACP), activity of lysozyme (Lyz), and immunoglobuline M (IgM) were better in both groups fed with 50 mg kg-1 ulvan diet. The SOD and GPx antioxidant gene expression were significantly high in both groups fed with any ulvan diet while the Nrf2 gene expression was high with 50 mg kg-1 ulvan diet. The IL-1ß, TNFα, hepcidin, Lyz, and IgM cytokines or proteins mRNA expression were significant in both groups fed with all ulvan supplement diet whereas the ß-2M expression was significant only with 50 mg kg-1 ulvan diet. The present research indicates that both L. rohita groups fed with 50 mg kg-1 ulvan diet significantly improved growth, antioxidant system, immune defense system, and immuno-antioxidant related gene expression against F. columnaris.

Effect of organic acid on recovery yields and characteristics of rohu (Labeo rohita) protein isolates extracted using pH shift processing.

BACKGROUND: Proteins recovery using hydrochloric acid (HCl) in acid-aided solubilization could cause greater loss in its functionality over alkali-aided solubilization. Moreover, using HCl in edible foods is also a health concern. Replacing HCl with organic acids for acid-aided solubilization could address these problems. The aim was to study the effect of organic acid (glacial acetic acid) as a replacement for HCl during pH shift processing on the characteristics and functionality of rohu (Labeo rohita) protein isolates. Rohu proteins were obtained by solubilizing at pH 3.0 and pH 11.0 using glacial acetic acid and sodium hydroxide (10 mol L-1 ). RESULTS: Results showed that solubilization at pH 11.0 gave higher protein yields (766.8 ± 2.4 g kg-1 ) compared to solubilization at pH 3.0 (735.7 ± 7.1 g kg-1 ) (P < 0.05). Isolates from acid-aided solubilization had higher whiteness and total pigment content over isolates obtained by alkali-aided solubilization. Rohu isolates recovered by alkaline solubilization showed higher water and oil holding capacity, gel strength, folding scores, foaming and emulsion capacity than acid processed isolates (P < 0.05). Solubilization of rohu proteins using glacial acetic acid produced isolates with low breaking force (149.0 g), low storage modulus (G') values and low folding test score (1.0) over the alkaline isolates (P < 0.05). CONCLUSION: Results indicated that, recovering rohu proteins using organic acid (glacial acetic acid) could produce isolates with poor functional properties, while using the organic acid to precipitate the proteins solubilized by alkali-aided processing could produce proteins with better yields and functionality. © 2019 Society of Chemical Industry.

Gonadotropin receptors of Labeo rohita: Cloning and characterization of full-length cDNAs and their expression analysis during annual reproductive cycle.

Follicle-stimulating hormone (Fsh) and luteinizing hormone (Lh), secreted from pituitary, stimulate gonadal function by binding to their cognate receptors FSH receptor (FSHR), and LH/choriogonadotropin receptor (LHCGR). Rohu (Labeo rohita) is a commercially important seasonal breeder freshwater fish species, but till date, the regulation of expression of gonadotropins and their receptors gene during different phases of annual reproductive cycle has not been investigated. We envisaged the critical role of these molecules during seasonal gonadal development in this carp species. We cloned full- length cDNAs of fshra and lhcgrba from rohu testis using RACE (Rapid amplification of cDNA ends) and analyzed their expression along with fsh and lh by quantitative real time PCR (qRT-PCR) assay at various gonadal developmental stages of the annual reproductive cycle. Full-length rohu fshra and lhcgrba cDNA encodes 670 and 716 amino acids respectively, and in adult fish, they were widely expressed in brain, pituitary, gonad, liver, kidney, head kidney, heart, muscle, gill, fin, eye and intestine. In male, both fsh and fshra transcripts showed high level of expression during spermatogenesis, however, in female, expression level was found to be higher in the fully grown oocyte stages. The expression of rohu lh and lhcgrba mRNA increased with increment of gonadosomatic index and showed highest level during spermiation stage in male and fully matured oocyte stage in female. These results together may suggest the involvement of fshra and lhcgrba in regulating function of seasonal gonadal development in rohu.

Effect of various acids on physicochemical and functional characteristics of gelatin from swim bladder of rohu (Labeo rohita).

Influence of various acids (acetic acid, phosphoric acid, and propionic acid) at different concentrations (0.05, 0.1, and 0.2 M) on the extraction yield, physicochemical and functional properties of gelatin from Labeo rohita swim bladder were investigated. Highest gelatin yield (44.22%, dry weight basis) was obtained in a sample prepared by without acid pretreatment (GWA) of swim bladder as compared to acid pretreatment counterparts. Amongst the acid pretreatments, propionic acid (GPrA) showed the highest gelatin yield, followed by acetic acid (GAA) and phosphoric acid (GPA) at all concentrations used, respectively. Moreover, with increased concentrations of all acids, the decrease in gelatin yield was observed for all the acids. GWA showed higher protein and hydroxyproline content than that of acid counterparts (P < 0.05). Amino acid analysis of gelatins showed glycine as the major amino acid in all gelatins followed by proline, glutamic acid and alanine, respectively. GWA showed α (α1 and α2) and ß-chains as the predominant components with low molecular weight peptides. However, GPrA, GAA, and GPA had α1 and α2 dominant constituents. FTIR spectra of gelatins revealed that the loss of the triple-helix was found in GPA, GAA, and GPrA, compared to GWA. Among gelatin samples, GWA showed the highest solubility at all pH tested followed by GPrA, GPA, and GAA respectively. Furthermore, GWA exhibited higher emulsifying, foaming and gelling properties as compared to GPrA, GPA, and GAA, respectively. Therefore, the acid pretreatment of swim bladder had a negative impact on the extraction yield, physicochemical and functional properties of gelatin from rohu swim bladder.

Antiproliferative, ACE-inhibitory and functional properties of protein hydrolysates from rohu (Labeo rohita) roe (egg) prepared by gastrointestinal proteases.

Previously, we have reported the chemical composition, molecular mass distribution and antioxidant activity of rohu roe protein hydrolysates. In the current study, antiproliferative, angiotensin-converting enzyme (ACE)-inhibitory activities and functional properties of protein hydrolysates from rohu (Labeo rohita) roe proteins, prepared by gastrointestinal proteases (pepsin and trypsin), were investigated. Antiproliferative activity was evaluated against human colon cancer cell line Caco-2. The results showed that the pepsin hydrolysate possessed dose dependent inhibitory effect on Caco-2 cell line. Pepsin and trypsin hydrolysates displayed ACE-inhibitory activity in vitro. The ACE-inhibitory activity of the hydrolysate generated by pepsin (47 ± 1.7 %, at 1 mg/ml) is higher than that obtained by trypsin (36 ± 3.2 %). Additionally, the undigested rohu roe proteins and its hydrolysates exhibited functional properties. Solubilities of the hydrolysates were above 81 ± 9.2 % at all pH values tested. Pepsin and trypsin hydrolysates showed good foaming capacity (45-211 %) and emulsification activity (4-29 m(2)/g). The foaming abilities and emulsifying activity index (EAI) were affected by pH. The results suggest that protein hydrolysates from rohu roe could be useful in food industry for various applications.

Optimization of process conditions for Rohu fish in curry medium in retortable pouches using instrumental and sensory characteristics.

'Kalia', a popular preparation of Rohu fish, packed in four-layered laminated retort pouch was processed in a steam/air mixture over-pressure retort at 121.1 °C to three different F 0 values of 7, 8 and 9 min. Time-temperature data were collected during heat processing using an Ellab Sterilization Monitoring System. Texture profile such as hardness, springiness, gumminess and chewiness decreased as the F 0 value increased. The L* values decreased whereas a* and b* values increased with increasing F 0 value. Based on the commercial sterility, sensory evaluation, colour and texture profile analysis, F 0 value of 8 min and cook value of 66 min, with a total process time of 41.7 min at 121.1 °C was found satisfactory for the preparation of Rohu fish curry (Kalia) in retort pouches.

Role of HSP70 in cytoplasm protection against thermal stress in rohu, Labeo rohita.

To understand the function of HSP70 of Labeo rohita (LrHSP70) in cellular protection, LrHSP70 ORF cDNA was inserted into the plasmid of pET-32a(+) or pEGFP-L1. Then, the recombinant plasmids were transformed or transfected into Escherichia coli cells, mouse myeloma cells (MPC-11) or fish hepatoma cells (PLHC-1). Western blot results revealed that LrHSP70 was expressed in E. coli cells and molecular weight was estimated to be 70 kDa. In cells, LrHSP70 was over-expressed following thermal or cold stress. Results revealed that LrHSP70 protected prokaryotic cells against thermal or cold extremes as well as played the same role in MPC-11 and PLHC-1 cells. After heat treatment at 42 °C for 1 h, the viability of the cell was declined considerably. PLHC-1 cells with pEGFP-L1/LrHSP70 exhibited a higher survival rate (50%) than wild-type cells (18%) or cells with only pEGFP-L1 (21.2%). When the time lag extended to 2 h, the survival rates were 30%, 3.4% and 5.3% respectively. The present study revealed that LrHSP70 plays an important role in response to thermal and cold stress in fish.

Molecular cloning, sequencing and tissue-level expression of complement C3 of Labeo rohita (Hamilton, 1822).

Complement component C3 plays a central role in all known complement activation pathways. In the present study, we cloned, sequenced and analyzed the full-length cDNA sequence of Labeo rohita complement C3 (LRC3). The expression pattern of complement C3 mRNA in different tissues of healthy rohu and after challenge with Aeromonas hydrophila were evaluated using real-time PCR. The LRC3 cDNA sequence of rohu comprised of 5081 bp encoding a predicted protein of 1645 amino acids. The deduced amino acid sequence had the characteristic domain architecture. About eight domains specific to complement C3 are present in the sequence starting from signal peptide to netrin C345C (NTR) domain. The post-translational processing signal sequence (RKRR), the C3-convertase cleavage site sequence (LAR) and the canonical thiol-ester motif (GCGEQ) were found to be conserved in the LRC3. Real-time PCR analysis revealed the highest expression of C3 in liver and extra-hepatic expression of C3 was also observed in all the tissues studied. A. hydrophila challenge resulted in significant up-regulated expression of C3 transcripts in both liver and kidney at 6, 12, 24, 48 and 72 h post-infection.

Understanding feeding competition under laboratory conditions: Rohu (Labeo rohita) versus Amazon sailfin catfish (Pterygoplichthys spp.).

Competitive interactions between species is widely prevalent within the animal world. In this manuscript, we attempted to understand feeding competitions between the Amazon sailfin catfish, an invasive species introduced globally, and rohu, a keystone species native to several countries within southeast Asia. We used two different size classes of each species, large-size having total length (TL, from snout tip to caudal fin) of 15-20 cm and fingerling having TL<6 cm, and feeding duration was used as a proxy to understand competition. Our results demonstrated that feeding durations of large-size rohu were either similar or significantly (P<0.05) higher in presence of catfish when compared to trials in presence of conspecifics, indicating that large-size rohu is not a weak competitor. However, feeding durations of fingerling rohu was significantly (P<0.05) reduced in presence of both large-size and fingerling catfish, when compared to trials in presence of conspecifics. Moreover, fingerling rohu also displayed freeze (alarm) behavior in presence of the catfish. Interestingly, presence of rohu had no significant (P>0.05) impact on feeding durations of catfish. Overall, the study demonstrated that invasive catfish may behaviorally outcompete fingerling rohu, thus, threatening the sustenance of a species that is native to several freshwaters around the globe.

Proteomic insights into extracellular matrix dynamics in the intestine of Labeo rohita during Aeromonas hydrophila infection.

In the aquaculture sector, one of the challenges includes disease outbreaks such as bacterial infections, particularly from Aeromonas hydrophila (Ah), impacting both wild and farmed fish. In this study, we conducted a proteomic analysis of the intestinal tissue in Labeo rohita following Ah infection to elucidate the protein alterations and its implications for immune response. Our findings indicate significant dysregulation in extracellular matrix (ECM)-associated proteins during Ah infection, with increased abundance of elastin and collagen alpha-3(VI). Pathway and enrichment analysis of differentially expressed proteins highlights the involvement of ECM-related pathways, including focal adhesions, integrin cell surface interactions, and actin cytoskeleton organization. Focal adhesions, crucial for connecting intracellular actin bundles to the ECM, play a pivotal role in immune response during infections. Increased abundance of integrin alpha 1, integrin beta 1, and tetraspanin suggests their involvement in the host's response to Ah infection. Proteins associated with actin cytoskeleton reorganization, such as myosin, tropomyosin, and phosphoglucomutase, exhibit increased abundance, influencing changes in cell behavior. Additionally, upregulated proteins like LTBP1 and fibrillin-2 contribute to TGF-ß signaling and focal adhesion, indicating their potential role in immune regulation. The study also identifies elevated levels of laminin, galectin 3, and tenascin-C, which interact with integrins and other ECM components, potentially influencing immune cell migration and function. These proteins, along with decorin and lumican, may act as immunomodulators, coordinating pro- and anti-inflammatory responses. ECM fragments released during pathogen invasion could serve as "danger signals," initiating pathogen clearance and tissue repair through Toll-like receptor signaling. IMPORTANCE: The study underscores the critical role of the extracellular matrix (ECM) and its associated proteins in the immune response of aquatic organisms during bacterial infections like Aeromonas hydrophila. Understanding the intricate interplay between ECM alterations and immune response pathways provides crucial insights for developing effective disease control strategies in aquaculture. By identifying key proteins and pathways involved in host defense mechanisms, this research lays the groundwork for targeted interventions to mitigate the impact of bacterial infections on fish health and aquaculture production.

Effects of thyroxin and luteinizing hormone releasing hormone on reproductive physiology of Rohu (Labeo rohita): Insights into spawning performance, oocyte maturation, steroidogenesis, and follicular development genes.

As the global aquaculture industry grows, attention is increasingly turning towards assisted reproductive technologies. In this study, we examined the impact of D-Ala6, Pro9-Net-mGnRH (LHRHa: 0.4 mL/kg) and two doses (1 and 10 µg/kg fish) of thyroxin (T4) administered through a single injection on oocyte maturation, spawning performance, sex steroid hormone levels, as well as the expression of genes related to steroidogenesis and follicle development (ZP2, Cyp19a1a and SF-1) in Rohu (Labeo rohita). The study found that untreated female Rohu did not spawn, while those treated with LHRHa and thyroxin ovulated and spawned across a hormonal gradient. The highest spawning success was observed with a thyroxin dosage of 10 µg/kg (no significant change with a dose of 1 µg/kg), and female latency period decreased with increasing dosage. Additionally, females treated with thyroxin exhibited significantly higher fecundity than other experimental groups. Treatment with LHRHa and two doses of thyroxin significantly increased the gonadal somatic index compared to the control and sham groups. Hormonal treatment also led to increased fertilization success, hatching rate, and larval survival. At 12 h post-injection, females treated with thyroxin exhibited a significant decline in estradiol levels and expression of Zp2, Cyp19a1a, and SF-1 compared to other experimental groups. Levels of DHP significantly increased across the hormonal gradient. Histological analyses supported a steroidogenic shift, where oocyte maturation was accelerated by hormone administration, particularly with both doses of thyroxin. In conclusion, the findings suggest that thyroxin is a recommended treatment for assisted reproduction of Rohu due to its ability to induce spawning, increase fecundity and improve larval survival.

Ameliorative Role of Vitamin C against Cypermethrin Induced Oxidative Stress and DNA Damage in Labeo rohita (Hamilton, 1822) Using Single Cell Gel Electrophoresis.

The present study was undertaken to evaluate cypermethrin (CYP)-induced oxidative stress [reactive oxygen species (ROS) and lipid peroxidation (LPO) in gills, muscles, brain, and liver tissues] and DNA damage/genotoxicity (peripheral blood erythrocytes) in a freshwater teleost rohu (Labeo rohita) and the protective role of vitamin C. The LC50 of CYP against rohu was found to be 4.5 µg/L in a semi-static culture system through probit analysis. Fingerlings of rohu were distributed into four groups (Group 1st served as a control, fed 35% protein basal diet and was not exposed to CYP; Group 2nd was fed a basal diet and exposed to CYP; Group 3rd and Group 4th were fed diets supplemented with vitamin C at the rate of 100 and 200 mg/kg diet, respectively, and exposed to CYP). Fingerlings were reared on a basal and vitamin C-supplemented diet for 28 days prior to exposure to CYP. The results indicate a time-dependent significant increase in ROS and LPO (indicated by time course increase in TBARS level) as well as DNA damage in terms of number of comets, % DNA in tail, tail moment, tail length, and olive tail moment after exposure to LC50 of CYP. However, statistically comparable results in both Groups 1st and 4th indicate the protective role of vitamin C. The results reveal the effectiveness of vitamin C as a feed additive for countering pesticides toxicity in Labeo rohita. The current study indicates CYP as a potential genotoxicant for fish and classifies SCGE as a reliable and sensitive tool for assessing DNA damage.