Background: Aeromonas veronii is the most common bacterium responsible for diseases in freshwater fish rearing systems. Multiple factors can be involved in the virulence processes of Aeromonas bacteria. Hence, the purpose of the present investigation was to evaluate the virulence genes, antimicrobial susceptibility and pathogenicity of A. veronii isolated from freshwater fishes.&nbsp; 
 
Methods: In this investigation, we isolated A. veronii from cultured freshwater fishes, Labeo rohita and Catla catla. A. veronii was identified by bacterial staining and culture characteristics. In addition, Polymerase chain reaction (PCR) was used to evaluate the distribution of nine virulence genes including aerolysin, cytotonic enterotoxin (442, 272 bp), elastase, enolase, flagellin, lipase, serine protease and DNase.&nbsp; 
 
Result: A total of 88 A. veronii strains were isolated, which includes 56 strains from rohu and 33 strains from catla. The strains were Gram-negative, rod-shaped, motile bacteria and the colonies are yellow on blood agar. All the A. veronii strains were positive for at least one or more virulence genes tested.&nbsp;The isolates carried more virulence genes, especially in the combination of aer,alt, ela, lip, AhyB genes were found to be more virulent. Antimicrobial susceptibility to 17 antibiotics was determined and the strains of A. veronii showed 100% resistance to tetracycline, pencillin and &beta;-lactum group of antibiotics. In addition, multiple antibiotic resistance (MAR) indexes ranged from 0.24 to 0.76, suggesting that they originated from high risk contaminated zones were (W. Godavari and Nellore districts) antimicrobials are often used.&nbsp;

Detection of Virulence Genes, Antimicrobial Susceptibility and Pathogenicity of Aeromonas veronii Isolates from Labeo rohita and Catla catla

<div style="text-align: justify;">The morphometric and molecular characterization of Thelohanellus catlae a new myxozoan belonging to genus Thelohanellus Kudo, 1933 (Myxosporea:Bivalvulida) infecting the gills of Catla catla were described in this study. The infection was observed as irregular, milky whitish, cyst-like plasmodia (up to 2.0-3.0 mm in diameter) attached to the gill filaments of the host fish. Each spore has a single pyriform polar capsule. Spores measured about 20.4&plusmn;0.69 (19.3-21.4) &times; &igrave;m long and 11.5&plusmn; 0.63 (10.7-12.4) &igrave;m wide. The polar capsule was 12.3&plusmn;0.70 (10.7- 13.9) &igrave;m long and 10.95&plusmn; 0.28 (9.7-12.9) &igrave;m wide. Sequencing of 18S rRNA gene of the new myxozoan revealed 98% sequence homology between the 18S rRNA gene of T.catlae. Phylogenetic analysis showed T. catlae within the clade of gill infecting myxosporeans and closed together with T. catlae. The importance of myxosporeans introduction to new locations along with infected cultured host is emphasized.</div>

<div style="text-align: justify;">Morphometric and molecular characterization of Thelohanellus catlae infecting the gills of Indian major carp catla, Catla catla (Hamilton, 1822) from West Bengal, India</div>

<div>Background: The popularity of snack foods among children and younger has attracted the attention of food processor for finding out new avenues of earning profit. Therefore, the aim of this research was to develop crackers from freshwater fish, catla and if found successful, become a part of food industry on large scale. 
 
Methods: Fresh fish, Labeo catla were procured from local market, available at Nagpur city, Maharashtra. The mince was prepared using meat mincer. The corn flour and seasonings were purchased from local market. The 60:40 ratio of fish mince to corn flour was used for making crackers. The minced meat, corn flour, salt and seasonings were mixed to form smooth dough. Dough was placed in boiling water at 100&deg;C, boiled for 15 minutes and cool down for 15-20 minutes. Dough was cut into 2-3 mm thick slices, sun dried for 2 days and fried in edible oil at 180-200&deg;C for 30 seconds. 
 
Result: The results indicate that crispy, golden brown colored crackers were developed from mince of catla fish with excellent nutritional quality. The developed crackers were rated as &lsquo;liked more&rsquo; among the panelists. This may replace wafers from plant origin in near future to meet the ever-increasing demand of nutritious food to the people.&nbsp;</div>

Development of Fish Cracker from Indian Major Carp, Labeo catla

<div style="text-align:justify">Background: Seed stunting is a process of suppressing the normal growth of fish by manipulating various factors affecting the growth process. The present study aimed at evaluating the influence of varied photoperiod and stocking density on the growth and survival of catla (Catla catla) during the stunting process. 
Methods: Five treatments including control were used in triplicate and stocked with catla fry (0.84 g, 38.8 mm). Control, T-1 and T-2 groups were stocked with fry at 20 m-3 densities and maintained at 12 hours light and 12 hours darkness (12L:12D), 6L:18D and 0L:24D, respectively to study the influence of varied photoperiod. T-3 and T-4 were stocked with fry at 30 and 40 m-3 densities respectively to study the effect of crowding on the growth. Control at 20 m-3 density and 12L:12D photoperiod served as control for both the studies.&nbsp; 
Result: There was a significant reduction in the survival, harvested body weight, total length and specific growth rate in the treatments T-1 and T-2 as compared to the control (P&lt;0.05). Though these attributes were statistically similar (P&gt;0.05) between T-1 and T-2, the values were relatively higher in T-1 suggesting considerable photoperiod effect on fish growth. Similarly, the HBW, total length and SGR significantly reduced from T-3 to T-4 with increased density depicting effect of crowding on growth. Such results indicated that both increased stocking density and decreased photoperiod lead to growth suppression and can be used as tools for seed stunting in catla.</div>

<div style="text-align:justify">Influence of Photoperiod and Rearing Density of Fry in Production of Stunted Fingerlings of Catla catla (Hamilton)</div>

<div style="text-align: justify;">&nbsp;The commenced investigation was conducted to assess the implication of tryptophan in diets of Catla catla. The fingerlings were fed with two different diets C1 and C2; in diet C1, mineral mixture (A) without L-tryptophan and in diet C2 mineral mixture (B) containing L-tryptophan, in addition to vitamins was used. After 90 days of the feeding trial, high growth performance, nutrition retention, and better immunity were observed in fingerlings fed on diet B signifying that tryptophan influences the growth performance and immune response. Excretion of metabolites (total ammonia excretion and orthophosphate production) was significantly low in the holding water when C. catla fingerlings fed on diet C2. Better growth performance and better water quality in treatment C2 may be attributed to the presence of essential vitamins and amino acid tryptophan. Hence, the incorporation of a mineral mixture containing L-tryptophan and vitamins in the fish diet appears to be significant for better growth, nutrition retention, digestibility and immunity.</div>

<div style="text-align:justify">Effect of Dietary Administration of Mineral Mixture Containing&nbsp;Amino Acid Tryptophan and Vitamins for Growth Performance&nbsp;and immunity of Catla catla (Hamilton, 1822)</div>

<div style="text-align: justify;">Reasonable evidences suggest that heavy metal pollutants have been added by factories and other industries to our local water bodies. The present study was conducted to determine the heavy metal (zinc and lead) concentrations in muscle tissues of Labeo rohita inhabiting local water bodies as well as those being raised at farms. Sampling was performed to collect Labeo rohita from two different stations along river Ravi, viz. Lahore Siphon (upstream) and Balloki Headworks (downstream). Additionally, samples were also obtained from the government operated as well as private fish farms located in Lahore District, Pakistan. The fish were dissected; their muscles were digested, filtered, and finally analyzed for concentrations of Zn and Pb. Significant variation of heavy metal ions were observed between two sites along river Ravi as well as government operated and private fish farms. Significantly high mean concentrations of Zn (10.7&plusmn;1.268) and Pb (0.61&plusmn;0.082) were observed at Balloki Head-works; whereas, the lowest Zn (1.58&plusmn;0.235) and Pb (0.16&plusmn;0.008) heavy metal levels were recorded in the muscle samples collected from private fish farms. It was also observed that the heavy metal concentration in the muscles of Labeo rohita, collected from Balloki Head-works was much higher than the permissible limits laid down by WHO/FAO. Further the recorded highest level of heavy metals in water samples collected from River Ravi indicates that the bioaccumulation of heavy metals is severely affecting the aquatic life of fresh water and industries should not be allowed to release their effluent directly into the river Ravi in their vicinity.</div>

Assessment of zinc and lead concentration in water and muscles of Labeo rohita collected from wild and local fish farms of Pakistan

<div>Background: Harike wetland (31&deg;08&cent; N to 31&deg;23&cent; N latitudes and 74&deg;90&cent; E to 75&deg;12&cent; E longitudes) is an internationally important Ramsar site, supports rare, vulnerable and endangered plants, fish and other faunal species. Weed infestation, pollution and encroachment are considered as important threats of its biota thus time series data with respect to fish diversity, catch composition and genetic variability has an utter importance to interpret changes over time. Cyprinidae family of freshwater fishes includes carps is the largest fish family found in Harike wetland comprising around 50% of total fish composition by weight basis and among carps, Rohu (Labeo rohita) is one of the commercially important food fish species available throughout the year and preferred by consumers. As river Beas and Sutlej, two major rivers of Indus river system confluence at Harike thus possibility of variation within fish stock is very high. With this background present study was carried out to evaluate the fish biodiversity and catch composition of Harike wetland. Study also emphasized on biometrics, length &ndash;weight relationship and genetic diversity based on mitochondrial marker genes of commercially important food fish Labeo rohita. 
 
Methods: Assessment of fish catch composition and diversity were conducted in landing centre adjacent to Harike wetland through Rapid Fisheries Assessment by Market Survey (RFAMS) technique. Fin tissue samples were collected for genetic diversity analysis of L. rohita by cytochrome oxidase subunit I (COI) gene sequencing, From the fish genomic DNA a partial fragment of approximately 655bp was PCR amplified by FishF1 (5&#39;-TCAACCAACCACAAAGACATTGGCAC-3&#39;) and FishR1 (5&#39;-TCGACTAATCATAAAGATATCGGC AC-3&#39;) primer pair. &nbsp;Calculation of intraspecific mean and pairwise distances was performed by MEGA 6.0 software using the K2P parameters 
 
Result: Total 30 species of fishes were recorded from Harike wetland and these belong to 14 families and 21 genera. In L. rohita average weight (Wt), total length (TL), standard length (SL) and forked length (FL) were recorded 2600&plusmn;5.64g (1700-3600 g), 58.2&plusmn;5.65 cm (51.3-67.6cm), 48.0&plusmn;8.54 cm (42.5-55.5cm) and 46.0&plusmn;0.25 cm (38.0-54.5cm), respectively. &nbsp;Biometric study revealed that sufficient numbers of mature L. rohita are available in wetland. L. rohita established negative algometric growth (b= 2.701); thus species became slender as it increased in length. The pairwise distances ranged from 0.00 to 18.49% with a mean &plusmn;S.E value of 4.70%&plusmn;0.40. Total of 9 haplotypes were observed in L. rohita COI sequences. The diversity in haplotype and nucletide values were observed 0.848 and 0.024, respectively. The present study states that L. rohita stocks in Harike wetland are genetically diverse.&nbsp;</div>

<div>Study on Biometric Parameters and Genetic Diversity of Labeo rohita from Harike Wetland-A Ramsar Site</div>

<div>Background: There is a scope of increasing the aquaculture production by use of fish feed produced from non-conventional ingredients and also improvement in the quality of feed by solid-state fermentation. The present study was conducted to investigate the effect of solid-state fermented aquafeed on growth performance, digestive enzymes and innate immunity of rohu, Labeo rohita. 
 
Methods: Fish feed containing sesame oil cake and mahua oil cake was fermented through solid-state fermentation by yeast, Saccharomyces cerevisiae and then compared with a non-fermented control feed with the same formula. 
 
Result: Solid-state fermentation increased crude protein (CP), decreased crude fibre (CF) and also lowered (p &lt; 0.05) anti-nutritional factors (ANF) of fish feed. After five months of experimental feeding, weight gain and digestibility of nutrients like dry matter, crude protein and ether extract were significantly higher (p &lt; 0.05) and feed conversion ratio was significantly lower in fish of fermented feed fed group than the control group. Furthermore, non-specific immune parameters such as lysozyme, myeloperoxidase and haemolytic activities and intestinal enzyme activity of fish fed with fermented feed increased significantly (p&lt; 0.05) compared to fish fed control feed. It is concluded that feeding of Saccharomyces cerevisiae fermented feed could improve the growth, digestive enzymes activity and immunity of Rohu, Labeo rohita.</div>

Effect of Solid-state Fermented Aquafeed on Growth Performance, Digestive Enzymes and Innate Immunity of Rohu, Labeo rohita&nbsp;

Background: Climate-Smart Aquaculture (CSAq) is built on three pillars, i.e., sustainably increasing productivity and income, improving resilience and mitigating climate change, respectively. Feed constitutes 60%-80% of the total production cost in aquaculture. The reduction of feed cost as well as the pollution originating from uneaten feed have always attracted the attention of aquaculture researchers. Adoption of an optimal feeding regime reduces both feed cost and nutrient loading in the ponds and in turn, enhances the income of farmers and reduces environmental impacts of aquaculture practices. Mixed feeding schedules, pulsed feeding or intermittent feeding have been proposed as some of the climate-smart methods to reduce feed cost and pollution by aquaculture and it has been successfully tested in many fish species. There is lack of sufficient reports on the impact of feeding regimes on the rearing of Labeo rohita, Rohu fry. The information will be useful to farmers for rearing of fry to fingerlings with reduced cost and environmental impact. 
&nbsp; 
Methods: A 90-day experiment was conducted to evaluate the growth performance and feed utilization of Labeo rohita fry under pulsed feeding regimes as a climate smart approach.&nbsp; For the experiment, the feeding regimes followed were, control (daily feeding @5% of the biomass), 1D4R (1 day starvation+ 4 days refeeding at 5% of the biomass), 2D12R (2 days starvation+ 12 days refeeding at 5% Biomass), 4D16R (4 days starvation+ 16 days refeeding at 5% biomass). The data obtained were subjected to statistical analysis using SAS 9.3. PROC GLM was used for analysis of variance (ANOVA) and Tukey&rsquo;s Honestly Significant Difference (HSD) test was used for all possible pair comparison of treatments at 5% level of significance. 
&nbsp; 
Result: The fishes under 1D4R exhibited significantly higher weight gain, SGR and feed conversion efficiency (FCE) and significantly lower FCR and production cost than the control group. Water quality parameters like Total NO2, NO3, total ammoniacal nitrogen and total phosphate were higher in the control group than in the treatments. The results suggest that one-day feed restriction followed by four days of refeeding could be an efficient strategy for rearing Labeo rohita fry to reduce production costs and environmental impact without compromising growth.

Pulsed Feeding Regimes for the Rearing of Labeo rohita (Hamilton) Fry: A Climate Smart Approach

<div>Background: Assam being a riverine state is home to n4umerous fish species that has been relished on for generations. However, fish being a perishable item, they need to be preserved for their availability throughout the year and to minimise wastage. The fish Labeo bata is a freshwater medium sized Indian minor carp which is very popular among the locals because of its characteristic taste and their high health ameliorating effects. Therefore, considering these facts, the present study focused on preparation and quality evaluation of fish powder from a minor carp, Labeo bata. 
 
Methods: Fresh fish collected from local fish market of Raha, Nagaon, Assam were dressed, washed and dehydrated to prepare fish powder. The prepared fish powder was evaluated for their nutritional composition, functional properties, sensory properties and shelf life as per standard protocols. 
 
Result: The results indicated that the moisture, protein, fat and ash content of prepared fish powder was 4.52, 63.87, 13.04 and 2.96 g/100 g respectively. The prepared flour had superior functional characteristics with bulk density, water absorption capacity, fat absorption capacity and foaming capacity of 0.53 g/ml, 145.00 ml/00 g, 99.00 ml/100 g and 32.20 per cent respectively. The product also displayed good shelf life when evaluated in terms of changed in moisture, free fatty acid (FFA), peroxide value (PV), total plate count (TPC) and pH across storage for a period of 90 days. The change in moisture, FFA, PV, TPC and pH content varied from 4.52-5.40 g/100 g; 0.08-0.22 per cent; 1.00-4.11 mEq O2/Kg; 3.12-4.23 log cfu/g and 6.22-6.80 respectively.</div>

Detection of Virulence Genes, Antimicrobial Susceptibility and Pathogenicity of Aeromonas veronii Isolates from Labeo rohita and Catla catla

Morphometric and molecular characterization of Thelohanellus catlae infecting the gills of Indian major carp catla, Catla catla (Hamilton, 1822) from West Bengal, India

Development of Fish Cracker from Indian Major Carp, Labeo catla

Influence of Photoperiod and Rearing Density of Fry in Production of Stunted Fingerlings of Catla catla (Hamilton)

Effect of Dietary Administration of Mineral Mixture Containing Amino Acid Tryptophan and Vitamins for Growth Performance and immunity of Catla catla (Hamilton, 1822)

Assessment of zinc and lead concentration in water and muscles of Labeo rohita collected from wild and local fish farms of Pakistan

Study on Biometric Parameters and Genetic Diversity of Labeo rohita from Harike Wetland-A Ramsar Site

Effect of Solid-state Fermented Aquafeed on Growth Performance, Digestive Enzymes and Innate Immunity of Rohu, Labeo rohita

Pulsed Feeding Regimes for the Rearing of Labeo rohita (Hamilton) Fry: A Climate Smart Approach

Quality Evaluation of Fish Powder Developed from Labeo bata, a Minor Carp of Assam