Neolissochilus Hexagonolepis Research Articles

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.

Molecular characterization of major and minor rDNA repeats and genetic variability assessment in different species of mahseer found in North India

Relationship among the mahseer species (Family: Cyprinidae) has long been debated in fish systematics. Present study concentrates on the nature of the phylogenetic relationship among the five mahseer species using the sequence of major ribosomal DNA (45S rDNA). We have covered rDNA sequence of approximately 5.2kb per individual, 26.0kb per species and 130.0kb as a whole. We also characterized the 45S and 5S rDNA regions with respect to their nucleotide composition. For phylogenetic analyses, nucleotide sequences were divided into four datasets. First and second datasets contained 18S rDNA and ITS1 sequence, whereas third and fourth datasets consisted of ITS2 and complete 18S-ITS1-5.8S-ITS2-28S, respectively. The NJ tree was constructed for all the datasets. The mahseer species under study formed a monophyletic group well separated from the outgroup species. Similarly, the individuals of Neolissochilus hexagonolepis form monophyletic group with Tor species, indicating Neolissochilus as a sister genus of Tor. The findings from the present study provide greater insights into taxonomic status of mahseer, and set the stage for future investigations dealing with phylo-geography, taxonomy, conservation and co-evolution within this interesting and important group of fish.

The Species Dilemma of Northeast Indian Mahseer (Actinopterygii: Cyprinidae): DNA Barcoding in Clarifying the Riddle

BackgroundThe taxonomic validity of Northeast Indian endemic Mahseer species, Tor progeneius and Neolissochilus hexastichus, has been argued repeatedly. This is mainly due to disagreements in recognizing the species based on morphological characters. Consequently, both the species have been concealed for many decades. DNA barcoding has become a promising and an independent technique for accurate species level identification. Therefore, utilization of such technique in association with the traditional morphotaxonomic description can resolve the species dilemma of this important group of sport fishes.Methodology/Principal FindingsAltogether, 28 mahseer specimens including paratypes were studied from different locations in Northeast India, and 24 morphometric characters were measured invariably. The Principal Component Analysis with morphometric data revealed five distinct groups of sample that were taxonomically categorized into 4 species, viz., Tor putitora, T. progeneius, Neolissochilus hexagonolepis and N. hexastichus. Analysis with a dataset of 76 DNA barcode sequences of different mahseer species exhibited that the queries of T. putitora and N. hexagonolepis clustered cohesively with the respective conspecific database sequences maintaining 0.8% maximum K2P divergence. The closest congeneric divergence was 3 times higher than the mean conspecific divergence and was considered as barcode gap. The maximum divergence among the samples of T. progeneius and T. putitora was 0.8% that was much below the barcode gap, indicating them being synonymous. The query sequences of N. hexastichus invariably formed a discrete and a congeneric clade with the database sequences and maintained the interspecific divergence that supported its distinct species status. Notably, N. hexastichus was encountered in a single site and seemed to be under threat.ConclusionThis study substantiated the identification of N. hexastichus to be a true species, and tentatively regarded T. progeneius to be a synonym of T. putitora. It would guide the conservationists to initiate priority conservation of N. hexastichus and T. putitora.

Nucleotide Sequences and Chromosomal Localization of 45S and 5S rDNA inNeolissochilus hexagonolepis(Pisces, Cyprinidae), Using Dual-Color Fish

Dual-color fluorescence in situ hybridization (FISH) was performed to study the simultaneous localization of major (45S) and minor (5S) family ribosomal RNA genes on chromosomes of Neolissochilus hexagonolepis. The partial 45S (18S, ITS 1, 5.8S, ITS 2 and 28S) and complete 5S (coding and NTS) rDNA units were amplified, sequenced, analyzed, and mapped on the metaphase chromosomes. The complete 18S, 5.8S and partial 28S rDNAs were 1849 bp, 157 bp and 1819 bp long, respectively. Internal transcribed spacers, namely ITS 1 (828 bp) and ITS 2 (359 bp), showed significant nucleotide variations from other fish species listed in NCBI database. The 5S rDNA contained an identical coding region of 120 bp and a highly divergent, non-transcribed 81-bp spacer. The specimens of N. hexagonolepis showed six bright fluorescent signals of 18S, while the 5S signals were present only on one pair of chromosomes. Subsequent analyses between conventional Ag-NORs and 18S rDNA FISH strongly suggested the possible inactivation of one pair of NORs that was localized at a telomeric position of a submetacentric chromosome. The sequencing and chromosomal localization of 45S and 5S rDNAs may serve as a useful genetic marker in taxonomic classification as well as in phylogenetic and evolutionary studies.

Fish Diversity of Tamor River and its Major Tributaries of Eastern Himalayan Region of Nepal

A total of 30 fish species from different sampling stations were recorded. Psilorhynchoides pseudecheneis, endemic fish of Nepal, was recorded from all seven stations, which can be considered as a common species of the study area. Recorded fish species were classified into two orders and five families. Order Cypriniformes comprised of four families: Cyprinidae, Cobitidae, Balitoridae and Psilorhynchidae with 26 species while order Siluriformes comprised of one family: Sisoridae and four species. Cyprinidae, Cobitidae, Balitoridae and Psilorhynchidae comprised 61%, 13%, 10% and 3% respectively while Sisoridae comprised of 13% fish species. The common species of Tamor river were Psilorhynchoides pseudecheneis followed by Barilius shacra, Barilius bendelisis, Barilius barila, Schizothoraichthys labiatus, Schizothoraichthys progastus, Schizothorax richardsonii, Neolissochilus hexagonolepis and Garra annandalei. Most of the species collected during the field survey have economic value as food, medicinal, recreation and aesthetic purposes. The water quality parameters i.e. air temperature (22-26.3°C), water temperature (16.0-19.0°C), DO (9.7-10 ppm), pH (7.3-7.5), alkalinity (17.1 mg/l), total hardness (28.5-34.2 mg/l), CO2 (5 mg/l) and conductivity (37.7-56.7 μs/cm) were found within the suitable range for cold water fishes.Key words: Eastern Himalayas region; Tamor river; Fish diversity; Fish dominancy; Physico-chemical parametersDOI: 10.3126/njst.v10i0.2964Nepal Journal of Science and Technology Vol. 10, 2009 Page: 219-223

Studies on Length-weight and Length-length Relationships of a Cold Water Fish Neolissochilus hexagonolepis (McClelland) from Tamor River, Nepal

Present paper attempts to describe length-weight (LW) and total length-standard length (TL and SL) total length and forkal length relationships of cold water fish Neolissochilus hexagonolepis. Fish of different length and weight were caught using cast net and scoop net at Mulghat vicinity, Dhankuta. The fish were kept in ice box in fresh condition and brought to fish laboratory, Department of Zoology, Post Graduate Campus, Biratnagar .The measurement of the fish samples was done with maximum accuracy. The data obtained from measurement were analysed using the formula W = aLb. The b values estimated for the total length and standard length in relation to body weight were 3.056 and 3.063, respectively. The values of b clearly indicate the isometric growth pattern.For total length, standard length and forkal length relationships, the linear values of b were 0.103 and -0.299. Similarly for the relationship between the forkal length and standard length the linear value of b was 0.346.DOI: http://dx.doi.org/10.3126/on.v9i1.5748