Performance of Different Biomaterials as Carbon Sources on the Immunological Response and Oxidative Status of African Catfish Clarias gariepinus in Biofloc Systems

A trial was performed to investigate how carbon sources can affect the welfare status of African catfish (3.8±0.2g and 8±0.11 cm) juveniles in biofloc systems. Inocula was prepared in glass tanks (5L) by adding 20g of pond bottom soil in well aerated water (1L) containing 10mg L-1 ammonium sulphate (NH)4SO4 and 400mg L-1 of four different carbon sources (tapioca, wheat offal, brewery and cassava peel) for 24 hours. Each treatment group (carbon sources and control) were replicated and each tank contained 1000 Clarias gariepinus juvenile, fed with commercial feed (Crude protein 42%) at 5% of their body weight 72 days. The water quality showed that all water parameters remained at concentrations suitable for Clarias gariepinus culture in the studied systems. The enzymes activities were noticed to be different across the biofloc and the selected organs. There were significant differences in serological content in fish between the treatment’s groups (P<0.05). The significant difference was found between the treatments in case of enzymes activity (P<0.05). The study shows that the welfare status with reference to digestive enzymes activity, oxidative status and extent of the immune system stimulation in BFT system is carbon source dependent.

Culture Possibilities of Certain Brackishwater Species at Freshwater: A Climate Change Adaptation Strategy for Salinity Intrusion Prone Areas of Indian Sundarban Delta

Salinity intrusion into coastal mainland or freshwater habitat because of recent climatic changes is exacerbating production risks and challenging the coping capacity of freshwater fish farmers of Sundarban coastal delta in India. Hence, an experiment was conducted to evaluate the survival and growth performance of certain commercially important brackish water species in freshwater, and subsequent low salinities (5 g l−1 and 10 g l−1). Species like Scatophagus argus, Chelon parsia, Terapon jarbua, Etroplus suratensis, and Penaeus monodon showed the highest specific growth rate (SGR) at 10 g l-1 salinity. However, the growth rates were not differed significantly (P>0.05) compared to freshwater. Chelon planiceps and Mystus gulio exhibited the highest SGR at 5 g l-1 salinity, although growth rates of the fish were not differed significantly (P>0.05) with freshwater treatments. Comparable survival and growth of all species in the freshwater condition indicated their ability of healthy acclimation at freshwater ponds. Therefore, these euryhaline fish species can be promoted in the Indian Sundarban for culture in freshwater ponds as climate-resilient adaptation strategies. This study could be useful in decision making during species and farm site selection which eventually will minimize the risks from total crop loss during saltwater inundation.

Dietary Supplement of Tumeric (Curcuma longa) Powder: Impact on Haematological and Biochemical Responses in Clarias gariepinus (Burchell, 1822) Fingerlings

Dietary supplementation with herbal extract in the diet of fish has been noted to increase aquaculture production through the improvement of immunity and other physiological dysfunctions related to fish health. A feeding trial was conducted to assess the impact of incorporating varied concentrations of turmeric powder (TP) on haematological and biochemical responses in Clarias gariepinus fingerlings. Five test diets were composed as T1 ((control) (basal diet + 0 % TP)), T2 (basal diet + 1 % TP), T3 (basal diet + 2 % TP), T4 (basal diet + 3 % TP) and T5 (basal diet + 4 % TP). Fish specimens were apportioned into five groups in triplicate. Significantly lower (P<0.05) red blood cell count was found in those fed control diet compared with the other inclusion. Highest values of white blood cell count were noticed in T5 when compared with the control. There were significant differences in haemoglobin between T1 and T5. Highest values of serum glutamic pyruvic transaminase, serum glutamic oxaloacetic transaminase, glucose and cholesterol level were found in T2 when compared with the control. TP can be used as feed supplement in the diet of C. gariepinus without any adverse effect on physiological responses of the fish.

Assessment of the Effect of Catosal on the Stimulation of Ovogenesis in Sterlet During Pre-spawning Period

Optimization of the process of sterlet feeding in recirculating aquaculture systems allows improving the physiological status and pre-spawning performance of fish. The addition of the organophosphorus compound Catosal based on butaphosphamide to pre-spawning feeds leads to an increase in glycogenogenesis in hepatocytes, which manifests itself as a decrease in cell and nucleus area (by 1.20 and 1.31 times), stabilization of nucleoplasmic ratios (0.28-0.25). Butaphosphamide also causes an increase in hemoglobin and serum protein concentrations by 6.1 g/L and 3.92 g/L, respectively. An increase in the live weight of sterlet by 98.0 g and an absolute increase in weight by 1.96 g associated with an improvement in hematological parameters was observed. The excess phosphorus in the form of butaphospham, which is not involved in the process of glycogenesis, is transported to gonads and stimulates vitellogenesis. The acceleration of oocyte development is determined upon reaching the optimal polarization coefficient (0.05≤Pc≤0.10, category II).

Target Market Selection for the Major Aquaculture Products of Turkey - An Evaluation on Export Markets by Hybrid Multi-criteria Decision-making Approach

After 50 years of rapid development, today's aquaculture industry has become one of the driving forces of economic growth in many countries thanks to the increasing aquaculture production. However, less attention has been given to its growing global market demand and its contribution to relevant countries’ trade potential. Turkey has achieved significant success in aquaculture production dominated by Trout (Oncorhynchus mykiss), Sea Bass (Dicentrarchus labrax), and Sea Bream (Dicentrarchus labrax)species thanks to its geographical and biodiversity advantages. Thereby, Turkey has an exporting advantage in the face of increasing global seafood consumption demand. In this paper, we focus on the target market selection of these priority products to support the exporting potential of Turkey. Therefore, this is a multicriterion problem, and this paper aims to provide forecasting about target markets based on qualitative and quantitative criteria by combining fuzzy analytic hierarchy process (FAHP) and the technique for order preference by similarity to ideal solution (TOPSIS) methods. Seven criteria as trade balance, consumption, distance, average tariff, ease of doing business, non-tariff requirement and logistics performance index were chosen for evaluating the target markets. According to FAHP results, the trade balance criterion has the most significant effect while the distance criterion has least effect on the decision problem for ranking the target countries. According to these seven criteria, Japan is the best target market for Trout and Sea Bass while Russian Federation is the best for Sea Bream.

Detections of Rainbow Trout Antibodies to Infectious Pancreatic Necrosis Virus and Viral Hemorrhagic Septicemia Virus via a Recombinant Protein-Based Enzyme-Linked Immunosorbent Assay

Infectious Pancreatic Necrosis Virus (IPNV) and Viral hemorrhagic septicemia virus (VHSV) cause significant losses in the aquaculture industry. There have been few reports of the use of screening rainbow trout for antibodies against IPNV and VHSV as an epidemiological tool. Several ELISAs using a whole virus or recombinant IPNV and VHSV proteins have been described. In this study, a recombinant protein-based enzyme-linked immunosorbent assay (ELISA) for the detection of IPNV and VHSV antibodies in rainbow trout (Oncorhynchus mykiss) was evaluated. To develop recombinant protein-based enzyme-linked immunosorbent assays, a fragment containing the entire length of the gG gene of VHSV and VP2 of IPNV was amplified by PCR using the viruses' genomic RNA and cloned in pET-28a(+) plasmid. Recombinant structural viral proteins (rVP2 and rgG) were expressed in the Escherichia coli BL21 (DE3). The rgG was extracted and purified. 96-well plates were coated with VP2 and gG separately. For VHSV, Assay could detect until 1/15625 dilution in VHSV positive fish serum. For IPNV, Assays could detect until 1/3125 dilution in IPNV positive fish serum. These results show rgG and rVP2, used in ELISA, are more sensitive than virus neutralization tests.

Utilization of Black Soldier Fly (Hermetia illucens Linnaeus) Larvae as a Protein Source for Fish Feed: A Review

Aquaculture plays a major role in curbing malnutrition and food insecurity. Nonetheless, aquaculture sustainability is threatened by expensive fish feeds due to the overreliance on fish meal (FM) as the main source of protein. Fish meal is not only expensive but also scarce due to declining capture fisheries and competition from other animal feed producers. This has prompted research on potential FM replacers, amongst them the black soldier fly (BSF) larvae (Hermetia illucens). The BSF larvae can effectively convert organic wastes into a potential valuable feed source, and its high nutritional content (crude protein of up to 64% dry matter) is vital for fish feed formulation. Nevertheless, there are no documented studies on the complete replacement of FM in the diets of fish using BSF larvae. Therefore, the current study reviewed 107 research publications related to BSF larvae vis-a-visfish feeds production to build capacity for existing theories, identify gaps, and suggest new and further research directions, based on the previous studies available in the area of larvae production and utilization in aquaculture nutrition. The study results are expected to help farmers make an informed decision on how to reduce the cost of fish production, increase yields, thus promoting food security, livelihoods, and ecological balance.

Combined Effects of Citric Acid and Phytase Supplementation on Growth Performance, Nutrient Digestibility and Body Composition of Labeo rohita Fingerlings

Aquaculturists have been concentrating their efforts to design aquafeeds using agro by-products to reduce feed costs. However, the presence of a wide variety of antinutritional factors (ANFs) in plant materials is one of the major obstacles. For this purpose, a 2x2 factorial experiment was established to evaluate the suitability of canola meal with citric acid (CA) and phytase (PHY) supplementation for growth performance, nutrient digestibility and body composition of Labeo rohita fingerlings. Five isocaloric and isonitrogenous diets; D1 (control; without CA and PHY), D2 (CA 15 g/kg+PHY 1000 FTU/kg), D3 (CA 30 g/kg+PHY 1000 FTU/kg), D4 (CA 15 g/kg+PHY 2000 FTU/kg) and D5 (CA 30 g/kg+PHY 2000 FTU/kg) were fed to fish (mean initial weight 7.61±0.31 g) in triplicates for 90-days. The growth performance was significantly increased while feed conversion ratio was decreased with D3 compared to control and other CA and PHY supplemented groups (P<0.05). Furthermore, higher digestibility (%) of nutrients (dry matter, crude protein and ash) and improved whole-body composition was also exhibited by fish fed with D3 (P<0.05). Hence, the above results elucidate that supplementation of 30 g/kg CA with 1000 FTU/kg PHY could be a useful approach for improved growth performance, nutrients digestibility and body composition of L. rohita.

Effect of Cassava Starch Sources on Growth and Feed Utilization of Nile Tilapia Fingerlings (Oreochromis niloticus) Reared Under Two Dietary Protein Levels

A 42-day experiment was performed to evaluate the growth performance and feed utilization of Nile tilapia (Oreochromis niloticus) fingerlings fed iso-lipidic diets (5% lipid) contain 17% or 25% of cassava starch extract from fresh root (R starch) or from dry chips (D-starch) at 37% and 30% protein levels. The diets were ie: 37% protein -FM25R17 & FM25D17, 30% Protein- FM15R25 & FM15D25. 144 fish (1.11+0.02g) were distributed in 12 tanks (54 L). Protein level or starch source had no impact on final weight, length, average daily gain, specific growth rate, food conversion ratio, hepato somatic index, viscero somatic index, and Whole-body composition of fish. Protein Efficiency Ratio was not affected by starch source; however, it was significantly higher in diets with low protein content. Apparent Digestibility Coefficient of dry matter was not affected by starch source but was significantly high in low (30%) protein diet. Inclusion of R starch substantially reduced the cost of feed and increased economic profitability. Tilapia fed FM15R25 diet showed similar growth and nutrient utilization to fish fed 37% protein diets and cost of FM15R25 diet was lower than other diets. Therefore, FM15R25 is the best practical diet among the tested diets for Nile tilapia fingerlings.

Potential Application of PCR Based Molecular Methods in Fish Pathogen Identification: A Review

Molecular biology developments have led to fast growth in new methods for fish disease diagnosis. Molecular diagnostic methods are rapid and more specific, more sensitive than the culture of pathogens, serology, histology, and biochemical methods which are traditionally utilized to identify causative agent fish disease. Molecular diagnostic methods are valuable for detecting specific pathogens that are difficult to culture in vitro or require a long cultivation period and it significantly more rapid in providing results compared to culture. It enables earlier informed decision-making and rapid diagnosis of bacteremia, particularly for low levels of bacteria in specimens. Molecular techniques which have the major significance are mainly PCR-based molecular diagnostic methods including Polymerase Chain Reaction (PCR), Real-Time Polymerase Chain Reaction (RT-PCR), Multiplex Polymerase Chain Reaction (multiplexPCR), and Random Amplified Polymorphic DNA (RAPD). These have been increasingly utilized to diagnose fish disease for the last recent years. Molecular diagnostic methods can detect pathogens from asymptomatic fish, so disease outbreaks could be prevented. As a consequence, antibiotic treatment can be reduced and the development of antibiotic-resistant bacteria can be eliminated. In this review paper, we attempt to summarize the potentiality of PCR-based molecular diagnostic methods and their application in fish pathogen identification.