Performance evaluation of the commercial aquafeeds available in the market of Pakistan on Channa marulius (Sole)

The present study aimed to determine the effect of different levels of protein on the growth, body composition, amino acid profile and serology of Channa marulius fingerlings. The experiment was conducted in ten happas installed in earthen ponds, each stocked with 10 fishes for 90 days. Four commercial fish feeds having 25%, 30%, 32% and 40% crude protein (CP) levels were fed to fish at 3% of their wet body weight three times a day. The results of the study revealed that highest weight gain, feed conversion ratio and survival rate were observed in 30% protein feed. Meanwhile, moisture content was higher in fish fed with 30% CP feed while highest crude protein was recorded in 40% CP fed fish. Lowest fat content was observed in 32% CP feed. Amino acid profile of fish revealed better results in 30% CP feed. Total protein, glucose and globulin were also highest in fish feeding 30% CP feed, while albumin was highest in 40% CP feed. It is concluded that 30% CP feed showed better results in terms of growth, amino acid profile and serological parameters without effecting fish body composition.

Length–weight relations of 14 fish species (Actinopterygii) from the Chalakudy River, Western Ghats, India

Length–weight relations of 14 fish species caught by small-scale fishery from the Chalakudy River of the Western Ghats biodiversity hotspot, India were analyzed from April 2018 to March 2019. The following species were studied: Amblypharyngodon microlepis (Bleeker, 1853); Dawkinsia filamentosa (Valenciennes, 1844); Puntius mahecola (Valenciennes, 1844); Osteobrama bakeri (Day, 1873); Labeo dussumieri (Valenciennes, 1842); Channa marulius (Hamilton, 1822); Channa striata (Bloch, 1793); Horabagrus brachysoma (Günther, 1864); Mystus armatus (Day, 1865); Pangasianodon hypophthalmus (Sauvage, 1878); Heteropneustes fossilis (Bloch, 1794); Etroplus suratensis (Bloch, 1790); Megalops cyprinoides (Broussonet, 1782); Parambassis thomassi (Day, 1870). The main fishing gear that was used in the data collection were gill nets, seine nets, and cast nets. The b values in the LWRs ranged from 2.649 (L. dussumieri) to 3.023 (P. hypophthalmus). This study reports the first LWR reference for five species and new maximum total lengths for five species. The results provide baseline information for the sustainable management and conservation of the studied species.

Length–weight relations of 14 fish species (Actinopterygii) from the Chalakudy River, Western Ghats, India

Length–weight relations of 14 fish species caught by small-scale fishery from the Chalakudy River of the Western Ghats biodiversity hotspot, India were analyzed from April 2018 to March 2019. The following species were studied: Amblypharyngodon microlepis (Bleeker, 1853); Dawkinsia filamentosa (Valenciennes, 1844); Puntius mahecola (Valenciennes, 1844); Osteobrama bakeri (Day, 1873); Labeo dussumieri (Valenciennes, 1842); Channa marulius (Hamilton, 1822); Channa striata (Bloch, 1793); Horabagrus brachysoma (Günther, 1864); Mystus armatus (Day, 1865); Pangasianodon hypophthalmus (Sauvage, 1878); Heteropneustes fossilis (Bloch, 1794); Etroplus suratensis (Bloch, 1790); Megalops cyprinoides (Broussonet, 1782); Parambassis thomassi (Day, 1870). The main fishing gear that was used in the data collection were gill nets, seine nets, and cast nets. The b values in the LWRs ranged from 2.649 (L. dussumieri) to 3.023 (P. hypophthalmus). This study reports the first LWR reference for five species and new maximum total lengths for five species. The results provide baseline information for the sustainable management and conservation of the studied species.

Nanoemulsion of Virgin Rapeseed and Sesame Oil improve Oxidation Stability and Sensoric acceptability of Vacuum Packed Fish Fillets

Background: Fish contains high polyunsaturated fatty acids and has good healthy biological values, so it is considered a vital ingredient in the human diet. Antioxidants play an essential role in the food industry due to their help breaking down the oxidation process. The consumer demands fresh refrigerated foods that extend shelf life without changing taste. By using oil and vacuum packaging techniques, considerable research has been conducted to preserve and extend the shelf life of Channa marulius fillets. Since rapeseed oil and sesame oil are considered good sources of antioxidants, their role in preserving and extending the shelf life of Channa marulius fillets is limited.Methods: Channa marulius fish fillets weighing 4-5 kg each were obtained from the market. The fillets were washed and divided into 5 groups using different concentrations of sesame oil (S.O) and rapeseed oil (R.O) nanoemulsion i.e., Control (C) without treatment, T1 (S.O 20%), T2 (S.O 25%), T3 (R.O 20%) and T4 (R.O 25%). The fillets were soaked in nanoemulsion for 30 minutes and packed with a vacuum packing machine before storing at -40 oC. After an interval of 0, 4, 7, and 15 days the oxidative stability, antioxidant activity and sensory evaluation determined of each treatment were determined. Result: Compared with the control group, the free fatty acid (FFA) levels and peroxide values (PV) values were lower in the treated groups. Lipid oxidation increased over time in the control group due to lipid oxidation. Total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of the fillets decreased due to the nanoemulsion. Oxidative stability fluctuated and increased with storage time because of more fatty acid hydrolysis. The reduction was noted in the antioxidant property because it hampered the oxidation stability. Channa marulius' sensory evaluation revealed that nanoemulsion and vacuum packaging had a higher sensory score than the control group. Conclusion: The role of rapeseed and sesame oil as natural antioxidants was investigated to preserve and extend the shelf life of Channa marulius fillets. The use of nanoemulsions by using sesame oil and rapeseed oil reduced the oxidation stability and enhance the antioxidant activity of Channa marulius fillets. Among the oils, it can be concluded that sesame oil can be recommended for nanoemulsion as a good preservative for fish fillets.

Comparative Study of Gender based Larvicidal Potency of Puntius ambassis, Ompak bimaculatus, Channa marulius and Heteropneustes fossilis Native Fish Species of Gwalior (M.P.) India: A Laboratory examination

Present study is focused on using some common native fish species of Gwalior (M.P.) as predator of mosquito larvae. All Predation experiments were conducted against mosquito larvae, pupae and alternative food (aquatic insects) at varying pray densities in separate aquariums containing analysed pond waters of Jal-vihar and fish farm of Gwalior (M.P.). The time duration of each predation experiments was three days and in each day, fishes were fed with mosquito larvae, pupae and alternative food at varying densities at different time intervals of a day. The study revealed that, Larvae consummation was positively related with the small fish species having female gender and prefered mostly small pray as food. Thus, small sized female fish species possessed greater predation efficacy on mosquito larvae and the sequence of larvicidal potency of female fish species was noted in the present study is Puntius ambassis>Ompak bimaculatus> Channa marulius> Heteropneustes fossilis. As per the results of our study, it is predicted that females have greater value of larvicidal potency than that of males. Thus, female gender plays an important and positive role of mosquito biocontrol at source level.

Studies on changes in muscle and liver glycogen in xylachlor induced fresh water teleostean fish, Channa marulius

Studies on Xylachlor (a weedicide) induced changes in plasma and muscle glycogen content have been made in an air breathing fresh water murrel fish, Channa marulius. It was observed that Xylachlor at all the concentrations (1.0 to 2.5ppm) caused marked effect on the levels of plasma as well as muscle glycogen of the fish under experiment causing a gradual decrease in the value as compared to control upto 96hrs of treatment in both sexes; thus indicating the deteriorated nutrient value of the fish exposed to xylachlor. The reason and mechanism of such changes have been discussed here.

Unexpected species diversity within Sri Lanka’s snakehead fishes of the Channa marulius group (Teleostei: Channidae)

The taxonomic status of the large snakeheads of the Channa marulius group that occur in Sri Lanka is reviewed and clarified. Two species are recognized from the island, based on both morphological and molecular (cytochrome c oxidase subunit 1: cox1) differentiation: C. marulius Hamilton from the northern dry zone and C. ara Deraniyagala from the middle and lower regions of the Mahaweli basin. Channa ara is endemic to Sri Lanka and can be distinguished from its Marulius group congeners, C. marulius, C. aurolineata and C. auroflammea, by having fewer dorsal- and anal-fin rays, fewer lateral-line scales and fewer vertebrae; from C. marulioides by a different adult colour pattern; and from C. pseudomarulius by having more vertebrae. At the cox1 barcoding locus, Channa ara is at least 3.6% genetically different from C. marulius, and at least 8% different from the other described species in the group. Specimens collected from the southwestern wet zone in Sri Lanka are a puzzling third component of the Marulius group’s diversity, uncovered in this study, and identified here as C. cf. ara. Whilst genetically more similar to C. marulius, C. cf. ara possesses fewer dorsal- and anal-fin rays, fewer lateral-line scales and fewer vertebrae and is therefore morphologically more similar to C. ara. Channa ara can be distinguished from C. cf. ara, however, by differences in circumpeduncular scale count, adult colour pattern, and by an uncorrected pairwise genetic distance of 3.7% in cox1 sequences. A neotype is designated for Ophicephalus marulius ara Deraniyagala.

Channa auroflammea, a new species of snakehead fish of the Marulius group from the Mekong River in Laos and Cambodia (Teleostei: Channidae)

Channa auroflammea is a new freshwater fish species of the Marulius group from the Mekong River system. Previously reported as C. marulius, C. cf. marulius, or C. aff. marulius, C. auroflammea is readily distinguished from C. marulius and other members of the Marulius group by a different colour pattern, and a DNA barcode sequence at least 6.5% divergent from other members of the group. Comparison of counts of vertebrae, dorsal-fin rays, and lateral-line scales reveals that these counts are lower in the Mekong C. auroflammea than in C. aurolineata from the Salween and Irrawaddy-Chindwin, higher than in the Marulius group species C. pseudomarulius and C. marulioides, but similar to those in C. marulius. Channa auroflammea is known from the Mekong river and tributaries in Laos and Cambodia, where it forms a regular component of the wild fisheries catch from the rivers Tonle San and Tonle Srepok. Literature records of Channa marulius from China appear to be based on confusion originating with Cuvier’s description of Ophiocephalus grandinosus.