Carcass characteristics of marketable size farmed catla,Catla catla (Hamilton, 1822)

The present study investigates carcass traits of farmed freshwater Catla catla for important information in calculating yield and/or providing data for programming machine/manual handling. For this purpose specimens of C. catla ranging from 1880 to 2150 g were collected from grow‐out culture ponds of the Central Institute of Freshwater Aquaculture, Odisha State, India. Carcass yield, offal yield and carcass cutability were assessed. The percentage of head yield was highest (31.2%) in comparison to other carp species. Gutted yield and final dressed yield of 2 kg market class catla amounted to 85.4 and 54.1%, respectively. The average meat : bone ratio in filleting was reported to be 3 : 9. The middle cut of catla had both the highest total yield percentage and highest meat yield. Dry matter, ether extract and protein percentage was highest in the fore cut followed by the middle and hind cuts.     

A murrel interferon regulatory factor-1: molecular characterization,gene expression and cell protection activity

In this study, we have reported a first murrel interferon regulatory factor-1 (designated as Murrel IRF-1) which is identified from a constructed cDNA library of striped murrel Channa striatus. The identified sequence was obtained by internal sequencing method from the library. The Murrel IRF-1 varies in size of the polypeptide from the earlier reported fish IRF-1. It contains a DNA binding domain along with a tryptophan pentad repeats, a nuclear localization signal and a transactivation domain. The homologous analysis showed that the Murrel IRF-1 had a significant sequence similarity with other known fish IRF-1 groups. The phylogenetic analysis exhibited that the Murrel IRF-1 clustered together with IRF-1 members, but the other members including IRF-2, 3, 4, 5, 6, 7, 8, 9 and 10 were clustered individually. The secondary structure of Murrel IRF-1 contains 27 % α-helices (85 aa residues), 5.7 % β-sheets (19 aa residues) and 67.19 % random coils (210 aa residues). Furthermore, we predicted a tertiary structure of Murrel IRF-1 using I-Tasser program and analyzed the structure on PyMol surface view. The RNA structure of the Murrel IRF-1 along with its minimum free energy (?284.43 kcal/mol) was also predicted. The highest gene expression was observed in spleen and its expression was inducted with pathogenic microbes which cause epizootic ulcerative syndrome in murrels such as fungus, Aphanomyces invadans and bacteria, Aeromonas hydrophila, and poly I:C, a viral RNA analog. The results of cell protection assay suggested that the Murrel IRF-1 regulates the early defense response in C. striatus. Moreover, it showed Murrel IRF-1 as a potential candidate which can be developed as a therapeutic agent to control microbial infections in striped murrel. Overall, these results indicate the immune importance of IRF-1, however, the interferon signaling mechanism in murrels upon infection is yet to be studied at proteomic level.     

Comparative studies on carcass characteristics of marketable size farmed mrigal Cirrhinus mrigala, (Hamilton, 1822), and silver carp Hypophthalmichthys molitrix, (Val., 1844)

The carcass traits and commercial characteristics of farmed freshwater Cirrhinus mrigala and Hypophthalmichthys molitrix were investigated to calculate yield data useful for programming semi‐automated processing units. Specimens with average weights of 2500 and 3400 g were collected from both mrigal and silver carps, respectively. Samples were taken from grow‐out culture ponds of the Central Institute of Freshwater Aquaculture (CIFA), Odisha State, India. Carcass and offal yields as well as carcass cutability were assessed. Head yields were recorded as 14.9 and 27.5% for mrigal and silver carp, respectively. The gutted yield, headless yield and skinless dressed round percentages were determined as 89.4, 74.5 and 67.6% for mrigal and 92.8, 65.4 and 62.0% for silver carps, respectively. The meat: bone ratio in filleting averaged 4.8 for mrigal and 3.1 for silver carp. The middle cut of mrigal had both the highest total yield percentage and highest meat yield, whereas this was equally distributed between both the fore and middle cuts in silver carp. In both mrigal and silver carp the dry matter, ether extract and protein percentages were highest in the fore cut followed by middle and hind cut. In silver carp the percentage fat content was found to be significantly higher than in mrigal.     

Carcass traits of two marketable size classes of Pangasius pangasius (Hamilton, 1822)

Carcass and commercial yield traits of Pangasius pangasius were evaluated and morphometric parameters measured along with carcass traits in two marketable weight classes (average ± SD) 1603 ± 49.5 g and 1985.6 ± 56.6 g. The Pangas fish head yield was 14.80% and 15.1% for the 2000 g and 1600 g weight classes, respectively. The offal percentage varied from 8.6 to 8.8 in both weight classes. Pangasius had a significant accumulation of fat deposits in mesenteric tissue and on the lining of the abdominal cavity. Headless (73.2%), head and skinless (68.7%), head, skin and boneless (57.7%) dressing yields were significantly higher in 1600 g than in the 2000 g weight class. The 2000 g weight class category exhibited mesenteric fat (4.3%), dissected subcutaneous and intramuscular fat (10.1%) which was significantly higher than in the 1600 g weight class. The yields of dressing stages were affected mostly by skin (8.3–4.5%) and mesenteric fat (4.3–3.7%), and dissected subcutaneous and intramuscular fat (10.1–6.8%), which is significantly higher in the 2000 g than in the 1600 g category. The later weight class category resulted in more meat yield, and less bone, skin and fat yields.     

Striped murrel S1 family serine protease: immune characterization,antibacterial property and enzyme activities

We report a molecular characterization of S1 family serine protease (SP-1) from snakehead murrel (or called striped murrel) Channa striatus (Cs). CsSP-1 polypeptide contained a catalytic core domain (otherwise known as serine protease trypsin domain) between H20 and I237 along with a catalytic triad at H⁶¹, D¹⁰⁴ and S¹⁹⁷. Phylogenetic analysis confirmed that CsSP-1 belongs to serine protease S1 family. The tertiary structure showed that CsSP-1 contains 14 β-sheets as 2 separate β-barrels (the first β-barrel consists of 8 β-sheets in the N-terminal region and the second β-barrel consists of 6 β-sheets in the C-terminal region) and 3 α-helical regions. Significantly (P < 0.05) the highest CsSP-1 mRNA expression was observed in intestine, liver and kidney, moderate expression was seen in spleen, head kidney, skin and blood, and the lowest one in brain, gill, muscle and heart. Further, the expression was induced in intestine with fungus Aphanomyces invadans and bacteria Aeromonas hydrophila. The recombinant CsSP-1 protein showed antibacterial activity against both gram-negative and gram-positive bacteria. The optimum CsSP-1 enzyme activity against the substrate casein was determined at 8 mM casein concentration. Moreover, the activity was highly influenced by 5 mM phenyl-methylsulfonyl fluoride followed by ethylenediaminetetraacetic acid, 4-(2-aminoethyl)benzenesulfonylfluoride hydrochloride and calpain inhibitor I. The CsSP-1 enzyme exhibited the highest activity at pH 7.5 and temperature 35°C. The overall results showed the potential involvement of CsSP-1 in the immune system of murrels. However, further research is necessary to study the mechanism of implicit trypsin association in the defence process.     

Observations on the hypophysation of murrels (Ophicephalidae)

The four common Indian species of murrels, viz., Ophicephalus striatus (Bloch), Ophicephalus marulius (Hamilton), Ophicephalus gachua (Hamilton) and Ophicephalus punctatus (Bloch) were hypophysed, the former three for the first time.The characters by which sexes in murrels can be distinguished, basis of selection of breeders, hormone doses administered and response, percentage of fertilization of eggs, techniques adopted for hatching of eggs and rearing of larvae and the total developing eggs and spawn produced are reported and discussed.     

不同捕食者暴露对鲫幼鱼行为、运动和形态特征的影响

自然界中鱼类的捕食者种类繁多,为验证猎物鱼针对不同捕食者是否会做出相异的反捕食策略选择,选取鲫（Carassius auratus）幼鱼为猎物鱼,乌鳢（Channa argus）和胡子鲶（Clarias fuscus）为捕食者,将鲫幼鱼分别暴露于空白（对照）、乌鳢、胡子鲶和双捕食者（同时存在乌鳢和胡子鲶）环境中持续2个月,随后考查不同组鲫幼鱼的生长、行为特征、形态和运动能力等指标之间的差异。结果表明：经过2个月的捕食胁迫处理,鲫幼鱼的自发运动、隐蔽场所利用率和勇敢性等行为指标在4个组之间均未表现出显著性差异。相比对照组,乌鳢、胡子鲶和双捕食者暴露组鲫幼鱼的快速启动反应时滞显著缩短（P<0.05）;但所有处理组中仅乌鳢暴露组鲫幼鱼的快速启动120ms移动距离（S_120ms）和体高（BD）显著高于对照组（P<0.05）。另外鲫幼鱼的临界游泳速度（U_crit）和活跃代谢率（M_O2active）在各组之间也未表现出显著差异。乌鳢暴露组鲫幼鱼快速启动能力的提升可能与形态上体高的提高有关;另外相比临界游泳能力,快速启动能力可能在鱼类逃避捕食者过程中更为关键;鲫幼鱼表现出对乌鳢的反应最为明显,可能与乌鳢口裂较大,给鲫幼鱼带来的威胁更大有关。整体而言,应对捕食胁迫时,鲫幼鱼仅表现出形态和快速启动能力的反捕食响应,其行为特征的保守性可能是对生长作出的妥协,这对于鱼类适应生境中长期存在的捕食胁迫十分关键。     

Mode of Association,Enzyme Producing Ability and Identification of Autochthonous Bacteria in the Gastrointestinal Tract of Two Indian Air-Breathing Fish,Murrel (<Emphasis Type="Italic">Channa punctatus</Emphasis>) and Stinging Catfish (<Emphasis Type="Italic">Heteropneustes fossilis</Emphasis>)

The mode of association of epithelium-associated bacteria in the gastrointestinal (GI) tract of two Indian air-breathing fish species, the murrel, Channa punctatus and the stinging catfish, Heteropneustes fossilis was demonstrated through scanning and transmission electron microscopy (SEM and TEM). The SEM examination revealed substantial numbers of rod shaped bacterial cells associated with the microvillus brush borders of enterocytes in proximal (PI) and distal regions (DI) of the GI tract of both the fish species. The TEM investigation indicated endocytosis and translocation of bacteria in the microvilli. The isolated bacterial strains (two each from the PI and DI of murrel and stinging catfish) were quantitatively evaluated for their extracellular amylase, cellulase and protease production. All the bacterial strains exhibited high cellulolytic activity than that of amylolytic and proteolytic enzymes. Only two strains, CPF1 and CPF2, isolated from the PI of murrel exhibited high proteolytic activity. Maximum amylase activity was exhibited by the strain, HFH5, isolated from the DI of stinging catfish. Totally six most promising enzyme-producing autochthonous bacterial strains were identified based on partial 16S rRNA gene sequence analytical results. All the strains showed close (92–99 %) similarity to Bacillus licheniformis.     

Saponins in Pollen

Phosphate buffered saline (PBS) extracts of pollen of 34 out of 95 angiosperm species (in 40 families) tested, lysed human and/or snake head fish (Channa striatus Bloch) erythrocytes during assay for lectins in pollen. The bitter taste of the pollen extracts of these 34 species, the formation of a stable foam on shaking and the ability to lyse erythrocytes, suggested the presence of saponins, which have not, so far, been reported from pollen. Thin Layer Chromatography (TLC) and Mass Spectrum (MS) of the erythrocyte-lysing extracts of pollen of the garden gladiolus (Gladiolus gandavensis Van Hout.) confirmed that the pollen contained both triterpenoidal and steroidal saponins. The implications for the presence of saponins in pollen inhaled from the atmosphere, in the diagnosis and management of pollen allergy are discussed.     

Carcass traits of different marketable sizes of rohu,Labeo rohita (Hamilton, 1822)

The present study was carried out to investigate the carcass traits of farmed freshwater Labeo rohita in relation to body size as important information to calculate yield and/or support for machine/manual processing. For this purpose ninety specimens were collected for nine weight groups from 600 to 1100 g, each group with a 100 g increment. Specimens were collected from grow‐out culture ponds of the Central Institute of Freshwater Aquaculture (CIFA), Bhubaneswar. The carcass evaluation technique was followed to evaluate carcass yield, offal yield and carcass cutability. Head size percentage of rohu increased as the body mass increased, which in turn increased the processing yield. Dry matter and ether extract percentage also increased with the body mass; however, moisture percentage showed a decreasing trend. The fore cut showed a distinctly higher ether extract percentage followed by the middle and posterior cuts. There was a good correlation development to describe the relationship between yield traits and body weight.     

Dietary niacin requirement of fingerling Channa punctatus (Bloch)

A 16‐week experiment was accomplished to determine the dietary niacin requirement of fingerling Channa punctatus (6.8 ± 0.92 cm; 4.65 ± 0.46 g) by feeding seven casein‐gelatin based isonitrogenous (450 g/kg CP) and isoenergetic (18.39 kJ/g GE) diets with graded levels of niacin (0, 10, 20, 30, 40, 50 and 60 mg/kg diet) twice a day to apparent satiation to triplicate groups of fish. Significantly best absolute weight gain (AWG; 38.19 g/fish), feed conversion ratio (FCR; 1.42) and protein retention efficiency (PRE; 26.47%) were registered in fish fed 40 mg niacin/kg diet. Also, fish fed above diet exhibited maximum carcass protein. Hemoglobin (Hb), RBCs counts and hematocrit (Hct) were improved with the incremental levels of dietary niacin up to 40 mg/kg. However, liver niacin content showed the positive correlation up to 50 mg/kg niacin and then leveled off. Fingerling C. punctatus fed niacin‐free diet showed retarded growth, poor feed utilization, high mortality, difficult motion and skin haemorrhage. Broken‐line regression analysis of AWG, FCR and PRE indicated that fingerling C. punctatus require niacin in the range of 37.1–42.1, whereas that of liver niacin concentration indicated the niacin requirement at 52.3 mg/kg dry diet.     

Isolation and multiplex genotyping of polymorphic microsatellite DNA markers in the snakehead murrel, Channa striata

Seven polymorphic microsatellite loci were isolated and characterized for the snakehead murrel, Channa striata (Channidae), a valuable tropical freshwater fish species. Among 25 specimens collected from Kedah state in Malaysia, the number of alleles per locus ranged from 2 to 7. Observed and expected heterozygosities ranged from 0.120 to 0.880 and 0.117 to 0.698, respectively. A single locus (CS1-C07) was significantly deviated from Hardy-Weinberg equilibrium after Bonferroni correction. These novel markers would be useful for population genetic studies of the C. striata.     

Morphometric,meristic and ISSR marker systems for species identification and evolutionary analysis in five Indian Channids

Snakehead species belonging to Channidae are primary group of freshwater air breathing fishes having their confined distribution in African and Asian continents. ISSR – PCR was used to investigate the phylogenetic relationship among five Channidae species viz. Channa striatus, Channa marulius, Channa punctatus, Channa diplogramme and Channa gachua. In addition, morphometric and meristic characters were subjected to principal component analysis (PCA) and the bootstrap values within the species were also calculated. The genetic identity between the species ranged from 0.5526 to 0.7632 and the genetic distance ranged from 0.2703 to 0.5931. The Nei's gene diversity (H) was calculated as 0.2653 and the Shannon's information index (I) was 0.3842. UPGMA dendrogram arrived by the morphological and molecular markers revealed the closeness between C. striatus and C. marulius among the five species.     

The effect of porcine calcitonin on plasma calcium in Channa punctatm Bloch

The effect of porcine calcitonin on the plasma calcium of the freshwater Indian murrel, Channa punctatus Bloch has been studied. An injection of 200 MRC mU of porcine calcitonin was given intraperitoneally, while control fish received the gelatin carrier. A significant hypocalcaemia was noted I h after calcitonin treatment (P < 0.001). The plasma calcium had returned to the normal level by the 6th h.     

An upstream initiator caspase 10 of snakehead murrel Channa striatus,containing DED,p20 and p10 subunits: Molecular cloning,gene expression and proteolytic activity

Caspase 10 (CsCasp10) was identified from a constructed cDNA library of freshwater murrel (otherwise called snakehead) Channa striatus. The CsCasp10 is 1838 base pairs (bp) in length and it is encoding 549 amino acid (aa) residues. CsCasp10 amino acid contains two death effector domains (DED) in the N-terminal at 2–77 and 87–154 and it contains caspase family p20 domain (large subunit) and caspase family p10 domain (small subunit) in the C-terminal at 299–425 and 449–536 respectively. Pairwise analysis of CsCasp10 showed the highest sequence similarity (79%) with caspase 10 of Paralichthys olivaceus. Moreover, the phylogenetic analysis showed that CsCasp10 is clustered together with other fish caspase 10, formed a sister group with caspase 10 from other lower vertebrates including amphibian, reptile and birds and finally clustered together with higher vertebrates such as mammals. Significantly (P < 0.05) highest CsCasp10 gene expression was noticed in gills and lowest in intestine. Furthermore, the CsCasp10 gene expression in C. striatus was up-regulated in gills by fungus Aphanomyces invadans and bacteria Aeromonas hydrophila induction. The proteolytic activity was analyzed using the purified recombinant CsCasp10 protein. The results showed the proteolytic activity of CsCasp10 for caspase 10 substrate was 2.5 units per μg protein. Moreover, the proteolytic activities of CsCasp10 in kidney and spleen induced by A. invadans and A. hydrophila stimulation were analyzed by caspase 10 activity assay kit. All these results showed that CsCasp10 are participated in immunity of C. striatus against A. invadans and A. hydrophila infection.     

Length–weight relationships of Channa punctata (Bloch, 1793) from Western Ghats rivers of Tamil Nadu

The study deals with the length–weight relationships of 1940 spotted murrel, Channa punctata (Bloch, 1793), collected in the Tamirabarani, Siruvani, Vellar and Cauvery rivers of Western Ghats, Tamil Nadu, India in the years 2001 through 2003. Lengths varied from 5 to 27 cm. Linear regression was used for the study and a trend line graph applied to compare conditions in the various rivers as per relationships. Results of the present study show that there is no significant difference (P > 0.005) in the length–weight relationship as a function of sex in the Siruvani, Vellaru and Cauvery populations, whereas there is a significant difference between males and females in the Tamirabarani population, indicating non‐homogeneity of these relationships.     

Molecular characterization of eight Indian Snakehead species (Pisces: Perciformes Channidae) using RAPD markers

Murrels (Perciformes; Channidei; Channidae) are unique group of freshwater air breathing fishes having a confined distribution to African and Asian continents. The phylogenetic relationship among eight Channid species viz. Channa aurantimaculata, Channa bleheri, Channa diplogramma, Channa gachua, Channa marulius, Channa punctatus, Channa stewartii and Channa striatus were investigated using RAPD markers. Eight random oligodecamers viz. OPAC03, OPAC05, OPAC07, OPAC09, OPAC19, OPA10, OPA11 and OPA16 were used to generate the RAPD profile. Estimates of Nei’s (Genetics, 89:583–590, 1978) unbiased genetic distance (D) demonstrated sufficient genetic divergence to discriminate the samples of different species and the values ranged from 0.3292 to 0.800 The present RAPD analyses strongly substantiate the view of earlier morphological and osteological studies of Channid species, the closer association among species in “gachua” and “marulius” groups.     

Novel pentapeptide,PALAL, derived from a bony fish elicits contraction of the muscle in starfish Patiria pectinifera

A bioactive peptide mimicking peptide‐signaling molecules has been isolated from the skin extract of fish Channa argus which caused contraction of the apical muscle of a starfish Patiria pectinifera, a deuterostomian invertebrate. The primary structure of the isolated pentapeptide comprises amino acid sequence of H‐Pro‐Ala‐Leu‐Ala‐Leu‐OH (PALAL) with a molecular mass of 483.7 Da. Pharmacological activity of PALAL, dosage ranging from 10^?9 to 10^?5 M, revealed concentration‐dependent contraction of the apical muscles of P. pectinifera and Asterias amurensis. However, PALAL was not active on the intestinal smooth muscle of the goldfish Carassius auratus and has presumably other physiological roles in fish skin. Investigation of structure‐activity relationship using truncated and substituted analogs of PALAL demonstrated that H‐Ala‐Leu‐Ala‐Leu‐OH was necessary and should be sufficient to constrict apical muscle of P. pectinifera. Furthermore, the second alanine residue was required to display the activity, and the fifth leucine residue was responsible for its potency. Comparison with PALAL's primary structure with those of other known bioactive peptides from fish and starfish revealed that PALAL does not have any significant homology. Consequently, PALAL is a bioactive peptide that elicits a muscle contraction in starfish, and the isolation of PALAL may lead to develop other bioactive peptides sharing its similar sequence and/or activity. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.     

Genotoxic and Mutagenic Assessment of Hexavalent Chromium in Fish Following In Vivo Chronic Exposure

Chromium is a well-documented carcinogen. To evaluate the genotoxic potential of hexavalent chromium on an aquatic bio-system, freshwater murrel fish (Channa punctatus) were exposed to potassium dichromate. The 96-h LC₅₀ for potassium dichromate was 61.80 mg/L for the test fish in a static system. On the basis of the 96-h LC₅₀, fish were exposed to sublethal concentrations of the test chemical. Fish exposed to the test chemical were sampled on days 1, 7, 14, 21, and 28 post-exposure and blood and gill cells were collected. Significantly (p < .05) higher DNA damage in both lymphocyte and gillcells and micronuclei formation in whole blood was observed at different test concentrations and sampling times of the test chemical as compared to control fish. The mean% tail DNA in the comet tail assay showed a concentration-dependent increase and the maximum% tail DNA was observed on day 7 of exposure in both cells. A similar trend was also observed in micronuclei induction in blood with maximum induction on day 21. Hexavalent chromium showed genotoxic potential in chronic exposure of C. punctatus, and the micronucleus test and the comet assay are the methods for sensitive and rapid detection of the genetic effects.     

Fishburgers with silver catfish (Rhamdia quelen) filleting residue

The utilization of filleting wastes from silver catfish in the formulation of fishburgers was evaluated by replacing grounded fish fillets with increasing levels (0-control, 20%, 50%, and 80%) of pulp obtained from filleting wastes (PFW). Fat content of burgers increased with increasing levels of PFW (p<0.05). Burgers with 50-80% PFW had lower n-6/n-3 ratio than control (p<0.05). Fat and moisture retention after cooking were not affected by PFW, while cooking yield increased in burgers with 50% PFW when compared to all other formulations (p<0.05). Texture and juiciness were not affected by PFW. However, burgers containing 80% PFW had lower overall acceptance than controls (p<0.05). Results indicated that production of fishburgers may be a valuable alternative for wastes from silver catfish filleting. Filleting wastes could substitute up to 50% of fish fillets with no changes in sensory acceptance and an improvement of nutritional value and cooking characteristics.