Schizothorax Richardsonii Research Articles

Evaluation of altitudinal distribution and population dynamics of introduced Brown trout (Salmo trutta) and native Snow trout (Schizothorax richardsonii) in river Asiganga, Uttarakhand (India)

Mountains of Himalaya, with unique topology and geographical regions, are hotspots of biodiversity. Their flora and fauna have been investigated for abundance in species composition and interactions. One of the most important driving forces of ecosystem differentiation is altitudinal gradients that results in changes in species composition. Sometimes, an introduced species can also have a major impact on endemic species if the introduced species can survive in entire altitudinal gradient zone. Our study focuses on this aspect and defines the pattern of altitudinal variation and distribution of Salmo trutta (Brown trout) and native Schizothorax sp. (Snow trout) in river Asiganga (a tributary of Ganges) that originates from Dodital (4400 m). We analyzed population dynamics of both species along altitudinal gradients (2200m to 1100m approximately). The physicochemical parameters of water showed significant variation along the altitudinal gradient. Our study suggests that the population groups of Brown trout are establishing in the lower altitudinal regions of the river Asiganga, and even into the river Ganges, due to their ability to survive in wider range of temperature and availability of food. Usually it is believed that species inhabiting higher elevations are superior competitors at lower temperature while species inhabiting lower altitude are better competitors at warmer temperature. Our study suggests that although altitudinal variations are powerful for species distribution but prey-predator effect and availability of preferred food is also pro-lasting and can have a wider role in distribution of predator fish species.

Transcriptional response to heat shock in liver of snow trout (Schizothorax richardsonii)--a vulnerable Himalayan Cyprinid fish.

The snow trout (Schizothorax richardsonii) belonging to family Cyprinidae, is an endemic fish of the Himalayan region. The species is tagged as vulnerable species in the IUCN red list of threatened species. The fish thrives well in snowmelt water of several streams and rivers in the region but are occasionally exposed to more than 20 °C during the summer season. Therefore, we have used deep RNA sequencing to decipher the transcriptome of snow trout and characterize the genes and molecular pathways involved in heat shock response. In this study 72,601,298 and 65,428,283 raw reads for heat-shocked and control, respectively, were obtained by Illumina paired-end sequencing technology. The de novo assembled transcriptome was tested for differential gene expression across the treatment groups. The quality of assembly was high with N75 and N50 lengths of 461 and 1274 bases, respectively. A total of 65 unique transcripts were differentially expressed in liver under heat shock and control. Annotated blast matches reveal that differentially expressed transcripts correspond to critical chaperones and molecular pathways, previously shown to be important for thermal stress in other fish species. Eight randomly selected heat-stressed responsive transcripts were also observed to be upregulated during qRT-PCR analysis. This study is the preliminary step to understanding the responses during sudden environmental changes like heat shock. The reference transcriptome database would also aid further studies on biological and physiological aspects of the snow trout under abiotic stresses.

Identification and In-Silico Analysis of Hepcidin from Tor Putitora (Hamilton)

Antimicrobial peptides extensively expressed in vertebrates, and invertebrates have assorted mechanisms of action and protect against pathogens. Liver-expressed antimicrobial peptide (LEAP) is a multifunctional cysteine-rich peptide that provides protection against infectious pathogens besides iron regulation. We have identified and cloned cDNA encoding LEAP from Tor putitora (TP-LEAP) as 440 bp fragment, with an open reading frame (ORF) of 279 nucleotides. The ORF encodes a pre-propeptide of 93 and a mature peptide of 25 amino acids. 3D model of the mature TP-LEAP, predominantly a β sheet, was generated and validated. Motif analysis and docking of TP-LEAP with iron transporter ferroportin revealed that the disulfide bonds are responsible for a stable structure besides interaction with ferroportin. Arg8 and Cys11, of mature TP-LEAP, formhydrogen bonds with Asn332 and Thr323 with bond lengths of 2.48A and 2.55A, respectively. TP-LEAP was phylogenetically closely related to Schizothorax richardsonii and Cyprinus carpio.

Activities of digestive enzymes in relation to ingested natural food in three carp species of the Himalayan River Ladhiya, northern India

The present investigation was carried out to study gut content and accompanying digestive enzyme profiles of the three carp species, golden mahseer Tor putitora, snow trout Schizothorax richardsonii and hill trout Barilius barila. The fishes were captured from the River Ladhiya, Champawat district, Uttarakhand, northern India. The digestive tract length was on average 1.8 and 2.3 times longer than the body, while members of Bacillariophyceae, Chlorophyceae, Cyanophyceae and Zygnematophyceae made up 95.15% and 99.63% of gut content in the golden mahseer and snow trout, respectively. In hill trout, the digestive tract being only half the body length, gut content was insects (72.73%), eggs of aquatic organisms (22.73%) and nematodes (4.55%). Estimated gut enzyme activities demonstrated that amylase activity was significantly (P < 0.05) higher in golden mahseer and snow trout compared to hill trout, while total protease, trypsin and chymotrypsin activities were all significantly (P < 0.05) higher in the hill trout compared to other species. A strong co-relation was found among relative gut length, food composition and digestive enzyme activities of each species. This may guide the future formulation of feed to these important species of carps kept in farm.

Molecular Cloning, Domain Analysis and Homology Modeling of Toll-Like Receptor 3 from Barilius bendelisis (Ham.)

Toll-like receptors (TLRs) are the evolutionarily conserved pattern recognition receptors that form an ancient arm of innate immune recognition. TLR3 is known to recognize double stranded RNA, a common viral replication intermediate in mammals and fish and, a potent indicator of viral infection. The authors cloned TLR3 from Barilius bendelisis, an Indian coldwater ornamental fish and analyzed the properties of the protein besides generating a three dimensional (3D) model. A polypeptide consisting of 867 amino acids was identified having a signal peptide of 22 amino acids, an ectodomain, followed by a trans-membrane region having 23 amino acids. A cytoplasmic domain [Toll/IL-1 receptor (TIR) domain], consisting of 111 amino acids was also detected. The authors have predicted 11 potential glycosylation sites in the ectodomain and two tyrosine phosphorylation sites in TIR domain. The molecular weight of TLR3 polypeptide was predicted to be 97.9864 kDa with an isoelectric point of 6.22. 3D model of ectodomain had a root mean square deviation (RMSD) value of 0.453 A over 656 aligned residues with 47–56 % sequence identity while, an RMSD value for TLR3-TIR domain was 0.443 A over 109 aligned residues with 34–86 % sequence identity. Phylogenetic analysis revealed a close relationship between TLR3 of B. bendelisis and snow trout, Schizothorax richardsonii.

Morphological Divergence of Snow Trout (Schizothorax Richardsonii, Gray 1932) from Rivers of Nepal with Insights from a Morphometric Analysis

Asala or snow trout (Schizothorax richardsonii, Cyprinidae), one of highly valued freshwater fish of Transhimalayan regions, is distributed in upper reaches of all major river systems of Nepal. Morphometric diversification between six river populations of S. richardsonii was examined to identify intraspecific unit for enabling better management of the resources. Significant differences were observed in 17 measured morphometric characters of 207 specimens among the six river populations. Multivariate analysis of variance (Wilks' test) indicated a significant difference for mean vectors of mophometric measurements (? =0.012, F85, 731 = 19.999, P&lt;0.0001) among populations. Principal component and discriminant functions (DFs) analysis of morphometric measurements revealed high seperation of the stocks. The analysis showed that most of the shape and size variation among these populations occurs in the head region, body depth and fin length. Apparent morphometric divergence among S. richardsonii samples showed the existence of three differentiated groups viz., the Indrawati and Khudi populations, the Melamchi and Phalaku Rivers, and the Sabha and Tadi River populations of Nepal. The results of this study may be useful in fisheries management and potential exploitation of this species in coldwater aquaculture.Int J Appl Sci Biotechnol, Vol 3(3): 464-473

Studies on gonadosomatic index, fecundity and hatchability of domesticated stock of asala Schizothorax richardsonii (Gray) from Nallu River of Lalitpur District

The present work embodies studies on the reproductive capacity of captive stock of asala Schizothorax richardsonii collected from Nallu River of Lalitpur district. Gonadosomatic index (GSI) estimates ranged from 3.08±0.9% in May to 26.55±1.8% in November. Positive correlation (r=0.667) was found between egg size and GSI. The egg size (2.7 to 2.9 mm) in October and November was significantly (P&lt;0.01) larger than the eggs measured in other months. Based on peak GSI level, S. richardsonii spawned by manual stripping in two breeding season i.e. winter (October-November) and summer (Mach-April) in Godawari (1500 masl). Mean incubation period of fertilized eggs was 259 h and 248 h during winter and summer season at 14.2 to17.5 oC and 14.5 to15.5 oC water temperature, respectively. Percent hatching rates of eggs ranged between 38 to 90% and were not significantly different (P&gt;0.05) between breeding seasons. Overripe eggs obtained during winter season breeding (16.5%) were significantly higher (P&lt;0.01) than the summer season breeding (3.6%). This suggests that more frequent observation of the spawner is necessary during winter season for recognizing their appropriateness to ovulation. DOI: http://dx.doi.org/10.3126/on.v12i1.12253Our Nature (2014), 12(1): 19-27

Occurrence ofIchthyophthirius multifiliis(White spot) infection in snow trout,Schizothorax richardsonii(Gray) and its treatment trial in control condition

High altitude raceways reared Schizothorax richardsonii stocks were monitored periodically for white spot infection at experimental coldwater fish farm, Chhirapani, Champawat, Uttarakhand. Total 1268 numbers of fishes with mean length (cm) ranging from 15.53 ± 0.20 to 16.86 ± 0.08, and mean weight (g) 24.70 ± 0.05 to 26.73 ± 0.06 were examined from January - December 2009. Presence of pinhead sized white spots (0.4 to 0.8 mm) was observed on dorsal body surface and caudal fins of sampled fishes during month of April. The causative agent was identified to be a ciliate parasite, Ichthyophthirius multifiliis. A temperature dependant infection pattern was noted with maximum prevalence (%) of 84.80 ± 1.83 in July followed by a decline in December (21.99 ± 2.13). Prevalence varied significantly (p< 0.05) between the months as water temperatures dropped with onset of winter. Trophont counts following dip treatment for five consecutive days under laboratory conditions with 2% common salt, 250 ppm formalin and a combination of the two, of samples of the snow trout, Schizothorax richardsonii, infected with Ichthyophthirius multifiliis, indicated that treatment with combination of salt and formalin was significantly (p< 0.05) effective than either salt or formalin alone in controlling the infection.

General biology and status of Schizothorax richardsonii in Nepal

Schizothorax richardsonii, commonly called as spotted snow trout, is a coldwater hillstream fish. It is a delicious fish and is important from sportive and commercial point of view. The hillstream modifications comprise presence of irregular folds of skin acting as papillated suckers on the ventral side of the head, closely situated smaller eyes, small gill openings, reduced air bladder and short-stumpy barbells. Body is spotted, slender and sub-cylindrical. It is a phytophagous fish with an adaptation in its mouth to scrap algae from the submerged rocks. Spotted snow trout can spawn naturally as well as artificially by stripping. Sexual dimorphism is vivid during breeding season. It starts spawning after second year. Spawning takes place twice in a year- October/November and March/April. Eggs are of sticky nature. Relative and absolute fecundities have been found about 12,000 and 30,000 eggs/kg respectively. Optimum temperature for incubation is 15-20°C and it takes about 11-18 days for hatching. S. richardsonii has low to moderate vulnerability in Nepal. The population of the fish is decreasing rapidly due to heavy fishing pressure, natural calamity and human disturbances.

Molecular cloning and characterization of mannose binding lectin homologue from snow trout (Schizothorax richardsonii).

The teleost fishes depend on their innate immune system for first line of defense. Mannose binding lectin (MBL) is a member of the collectin family of proteins that plays an important role in the innate immune response in many vertebrates including fish. The present study was thus carried out to identify and characterize MBL homologue from snow trout. The cDNA of snow trout MBL homologue (galactose binding; Sch-GBL) was cloned and characterized. The obtained cDNA (778-bp) contains 762 bp long ORF (open reading frame) and a 16 bp partial 3'UTR (untranslated region); transcripts are ubiquitously expressed in all the tissues under study. Sch-GBL encodes a 253-aa protein that clusters with that of common carp, goldfish and contain several common structural motifs. In addition, the K(a)/K(s) ratios of the C-type lectin domain sequences depicts that they are under negative selection. Sch-GBL transcript level increases in response to challenge to Aeromonas hydrophila infection and decreases in response to downshift in temperature. Altogether, these findings suggest that Sch-GBL play an important role in the first line of fish defense mechanisms.

Fish assemblage structure and habitat use of the snow fed stream Assiganga - a major tributary of river Bhagirathi in Central Himalaya (India)

Assiganga stream is an important tributary of Bhagirathi River in central Himalaya (India). The stream is characterized by heterogeneity in habitat and substratum features harboring diverse fish fauna. At present this stream is facing threat of being fragmented by the construction of two hydro-electric projects. Present study aimed to study fish diversity and their habitat use in Assiganga stream. This study reports fifteen species (14 indigenous and 1 exotic) belonging to 8 genera, 4 families and 3 orders. Snow trout, Schizothorax richardsonii (Cyprinidae family) and Salmo trutta (Salmonidae family) were the dominant species (> 65% of total fish catch) throughout the entire length of stream. The presence of rich benthic food, clear water, low turbidity (01-05 NTU), high DO (8.75-10.75 mg-l), and high water velocity (1.10-1.40 m-s) with characteristic rapids and cascades in upper reaches provides ideal habitat for the existence of native snow trout and exotic trout species. Few cat fishes, loaches, Tor spp. and lesser barils also have been reported during the study.

Mitochondrial Dna Variation and Population Genetic Structure of Snow Trout from Kumaun and Garhwal Himalayan Regions of India

Snow trout (Schizothorax richardsonii) is one of the economically important coldwater fish, widely used as a food fish in the Himalayan region of India. The present study examined the genetic variations between five geographically isolated populations of S. richardsonii using ATPase 6/8 and COI gene sequences of mitochondrial DNA. Analysis of 25 sequences of ATPase 6/8 gene (842 bp) and 22 sequences of COI gene (847 bp) revealed 16 and 8 haplotypes respectively. The estimated haplotype and nucleotide diversity was high in GR (Gola river, Ranibagh) population (h = 1.00000, π = 0.00475 for ATPase6/8 and h = 0.83333, π = 0.00354 for COI). Results of AMOVA indicated that majority of the genetic variations in both genes are due to variation among populations (65.41 % for ATPase6/8 and 55.57 % for COI gene). The pairwise FST comparison and Neighbour-joining tree revealed low genetic divergence of KU (Kosi river, Uttarwahini) and KR (Kosi river, Ramnagar) population from other populations. The findings of this study showed that variation levels detected by ATPase6/8 and COI gene in population of S. richardsonii were very close to each other and demonstrate utility of ATPase6/8 and COI gene sequences for the population study of S. richardsonii for conservation, breeding and management progammes.

ENVIRONMENTAL EFFECTS ON THE MORPHOLOGY OF THE SNOW TROUT Schizothorax richardsonii (GRAY, 1832)

This study examines the relationship between morphological traits related to body size and fin morphology and the environment in snow trout, Schizothorax richardsonii, a widespread species from the upper Ganga river basin, India. Three body shape traits (index of compression, index of trunk shape and relative body depth) and three fin traits (dorsal fin relative area, pectoral fin relative area and pectoral fin aspect ratio) were related to five environmental variables (water temperature, water flow, depth, conductivity and substrate diversity) across eight study streams. Water temperature, conductivity and substrate diversity were highly variable across the sampled sites. There was a significant negative correlation (r = -0.676) between composite morphological traits (principal components) related to body size and fin morphology. Furthermore, both body size and fin morphology were strongly correlated (r = 0.861 and r = -0.845 respectively) with composite environmental variables (water temperature, conductivity and substrate diversity) across sites. These findings suggest that the morphological traits of fish populations residing across environmental gradients are adapted to different habitats.

Genetic Diversity in Four Species of Coldwater Fishes (Family Cyprinidae) Using Random Amplified Polymorphic DNA Markers and Implication for their Conservation

Information on the genetic profile of cultivable fish species is essential for studying molecular systematic and optimizing fisheries management and fish farming. In the Kumaun and Garhwal regions of Uttarakhand Himalayas, coldwater fish species (Cyprinidae) is widespread and endemic in the natural water bodies. The usefulness of random amplified polymorphic DNA (RAPD) was examined as a potential tool to test the genetic relationship among four predominant fish species, viz., Tor putitora, Schizothorax richardsonii, Garra gotyla and Barilius bendelisis (Cyprinidae: Pisces). The samples were collected from two different geographical region of Kumaun and Garhwal of Uttarakhand. Species specific markers were observed using 10 mer random primers through RAPD-PCR assay. The statistical analysis of RAPD was performed with the software POPGENE version 1.31. The phylogenetic trees based on RAPD-PCR, by using 15 random primers, showed a consistent result of forming two separate monophyletic groups consisting of T. putitora with S. richardsonii and Garra gotyla with B. bendelisis. The present investigation concluded that these methods could be a valuable tool for studying molecular systematic and establishing the taxonomic position among cyprinids coldwater fish species of India.

Characterization and Structural Analysis of Hepcidin Like Antimicrobial Peptide From Schizothorax richardsonii (Gray)

Innate immune system is a primary line of defense in fish that protects it from the invading pathogens. Antimicrobial peptides (AMPs) are widely distributed in nature and are essential components of innate immunity. These molecules enable the host's innate immune system to fight against a variety of infectious agents. One such AMP, hepcidin, is a cysteine rich amphipathic peptide. We have amplified, cloned and characterized hepcidin like AMP from Schizothorax richardsonii that inhabits one of the most difficult aquatic ecosystems in the Indian Himalayas. The cDNA encoding hepcidin like peptide was amplified as a 371bp fragment with an open reading frame (ORF) of 279 nucleotides flanked by 5' and 3' UTRs of 70 and 22 bases respectively. This ORF encodes a peptide of 93 amino acids with a signal peptide of 24 amino acids and a mature peptide of 25 amino acids. The mature hepcidin like peptide of S. richardsonii has eight cystine residues that participate in the formation of four disulfide bonds, a unique feature of hepcidin like AMPs. A 3D model of hepcidin like mature peptide was generated using Modeller 9.10 which was validated using PROCHECK and ERRAT. Phylogenetic analysis of hepcidin like AMP from S. richardsonii revealed that it was closely related to hepcidin from olive barb (Puntius sarana).

Fish diversity of Laster stream, a major tributary of river Mandakini in Central Himalaya (India) with regard to altitude and habitat specificity of fishes

Laster stream is a major tributary of river Mandakini, which in turn is a major tributary of river Alaknanda. Stream traverses a distance of ~40 km before joining with river Mandakini at Suryaprayag (Tilwara) in Rudraprayag district (Uttarakhand), India. Present study reports existence of twenty one indigenous fish species belonging to eight genera, three families and two orders from the Laster stream. Schizothorax richardsonii (Cyprinidae family) was the dominating species followed by S. plagiostomus, Barilius sp., Tor sp., Noemacheilus sp., Pseudecheneis sp., Glyptothorax sp. The distribution pattern (diversity and abundance) of these species had negative co-relation with the increase in stream altitude. Habitat conditions in the stream varied considerably from headwater to main stream. Present study also describes the habitat specificity of fish assemblage. Maximum species diversity (18 species) was recorded from pool habitat and was the most preferred habitat. Least species diversity (09 species) was recorded from cascade habitat. Riffle and rapid habitat recorded no difference in species diversity.

Length–Weight Relationships and Condition Factor of Snow Trout, Schizothorax richardsonii (Gray, 1832) From Different Rivers of the Himalayan Region in India

The present study describes the length–weight relationship and condition factor of a vulnerable indigenous snow trout, Schizothorax richardsonii (Gray, 1832) of the sub-family Schizothoracinae from different Himalayan rivers/streams of India. A total of 254 samples of S. richardsonii were measured from the rivers Ravi, Sahoo, Sewa (Chamba District, H.P.), Teesta (North West Bengal) and Indus (Leh, Jammu and Kashmir). The values of regression coefficient (b) ranged from 2.44 to 3.11 (r 2 > 0.97). The values of regression coefficient in rivers Sewa, Ravi and Sahoo were 3.03, 3.07 and 3.11, respectively (close to 3.0) indicating isometric growth; in rivers Teesta and Indus, the values of b were below isometric value (significantly <3.0) demonstrating negative allometric growth. The values of condition factor showed significant differences between rivers and ranged from 0.60 to 1.27. The findings of the present study could be useful to help in conservation and sustainable fisheries management of this indigenous species.

Nutritional Quality in Terms of Amino Acid and Fatty Acid of Five Coldwater Fish Species: Implications to Human Health

Muscle samples of Tor putitora, Neolissochilus hexagonolepis, Oncorhynchus mykiss, Schizothorax richardsonii and Cyprinus carpio were analyzed for fatty acid and amino acid composition with a view to generate nutritional information of the five important coldwater fish species of Indian upland Himalayan region. In the present study, all the fish species recorded good amounts of n-3 fatty acids (8.69–21.48 %) and the n-3/n-6 ratio ranged from 0.7 to 4.98. The amino acid score calculated based on the World Health Organization (WHO) protein standard indicated good quality proteins in the species but with mostly marginally lower values for C. carpio. However, when the amino acid levels of the fish species were compared with the recommended amino acid levels, all the fish species were found to constitute a good source of essential amino acids. Limiting amino acids such as lysine, methionine and cysteine occurred at levels higher than or marginally lower than the recommended amino acid profile. It could be concluded that the five coldwater fish species from upland Himalayan region contained high quality lipids and proteins constituting a healthy addition to the human diet.

Complete mitochondrial genome organization of Schizothorax richardsonii (Gray, 1832)

The complete mitochondrial genome of Schizothorax richardsonii, an endemic coldwater fish of Himalayas, was determined for the first time. The genome is 16,592 bp in length and consists of 13 protein coding genes, 22 tRNAs, 2 rRNA genes and one putative control region. The gene organization and its order were similar to other vertebrates. The overall base composition was as follows: A: 29.9%, G: 17.7%, C: 26.9%, T: 25.5%, A + T content 55.4% and the G + C content 44.6%. The control region contains a microsatellite; (TA)13 exists between 16,469 and 16,494 bp. This study will provide the rationale for the management and conservation of the snow trout.

A SRCF cell line from snowtrout, Schizothorax richardsonii: Development and characterization

Schizothorax richardsonii, commonly called snowtrout, is an important indigenous coldwater fish of the Himalayas, India with high commercial values as food and game fish. A cell line named as SRCF was developed from the caudal fin tissue of S. richardsonii. The cell line has been maintained in Leibovitz's L-15 medium supplemented with 10% fetal bovine serum (FBS) at 24°C. The cells showed fibroblastic morphology, high plating efficiency and cell doubling time of 48h. Chromosomal analysis of SRCF cells revealed a diploid count of 98 chromosomes. The origin of the cell line was confirmed by the amplification of 655 and 578bp of cytochrome oxidase subunit I (COI) and 16S rRNA of mitochondrial DNA (mt-DNA) genes, respectively. Transfection of SRCF cells with pEGFP-C1 plasmid resulted in bright fluorescent signals, suggesting the application of cell line in transgenic and genetic improvement programme. In addition, genotoxicity assessment illustrated the utility of the cell line as an in vitro model for aquatic toxicological studies.