Semi-intensive Culture System Research Articles

Effects of different traditional and commercial feed on growth, survival and proximate composition of Rohu (Labeo rohita) reared in the semi-intensive composite culture system.

This study was investigated to assess the effects of different traditional and commercial aqua feed on proximate composition, growth performance and survival rate of Labeo rohita reared in the composite semi-intensive culture system. The aqua feeds of various companies (AMG, Supreme, Aqua, Star Floating, Hi-Pro and Punjab feed) used as commercial feed. Farm made feeds were maize gluten and rice polish. For confidentiality, these feeds were randomly given code labels T1, T2, T3, T4, T5, T6, T7 and T8 which were only known to investigating staffs. There were two replicates for each treatment. In this experiment, higher growth rate was observed in T3 as compared to other treatments. Lesser weight gain was observed in the T1 ( 270.30 ± 0.5 ). The maximum body length ( 19.25 ± 2.19) was found in T3. Similarly, the minimum body length (5.97 ± 2.94) was seen in T2. FCR ratio (2.36 ± 0.01 ) was recorded in T3. Simultaneously, FCR (1.86 ± 0.002 ) was also recorded in T4 that is the perfect ratio for farmers. Higher SGR was noted in T3 (1.62 ± 0.05 ). Overall, T4 showed lesser SGR (1.05 ± 0.001 ). T4 showed the higher crude protein ( 28.66 ± 0.24 % ). In the body composition higher level of fat content was recorded in T3 ( 5.46 ± 0.33 %). These outcomes also proved that the rise in the dietary protein level and lipid content can improve the fish's body crude fats and protein level. Thus, based on growth performance, survival and proximate composition. It is concluded that T3 and T4 may be recommended for commercial culture of L. rohita.

Effect of Stocking Density on Growth, Survival and Production Performances of Clarias Batrachus Fry in Nursery Hapa Under Semi-intensive Culture System of Rajshahi University Campus, Bangladesh

An experiment was conducted to assess the effect of stocking density on growth, survival and production performance of Clarias batrachus (Magur) fry using nursery hapa in experimental pond of Dept. of Fisheries, University of Rajshahi. The research was carried out for a period of three months from May to July, 2021 consisting of four treatments each with two replications. A total of eight hapa were prepared using net each having an area of 1.2 × 0.9 × 0.9 m3. Stocking density was maintained at the rate of 300, 350, 400 and 450 fry ∕ m3 in T1, T2, T3 and T4 respectively where the mean initial weight of hatchling was 0.04±0.01 g. Different physico-chemical parameter of water were monitored fortnightly where the mean value of water temperature, water transparency, dissolved oxygen, carbon dioxide, PH and NH3-N was observed 28.25±1.18°C, 26.12±0.18 cm, 8.44±0.45 mg/l, 1.78±0.03 mg/l, 6.88±0.04 and 0.007± 0.00 mg/l respectively. Except NH3-N no significant difference (p˃0.05) was found among the treatments and all the parameter were in suitable range for fry rearing. Highest mean final weight, weight gain, SGR (%/day), survival rate, along with lower FCR was found in T1 which was 8.00±0.13 g, 7.96±0.07 g, 5.65±0.00 (%/day) and 91±0.70 (%) respectively followed by T2, T3 and T4 where significant variation (p˂0.05) was found among them. Maximum net yield (kg/m3/90 days) was 2.51±0.07 which was obtained from T3 followed by 2.48±0.02, 2.37±0.02 and 2.20±0.05 in T4, T2 and T1. On the other hand, benefit cost ratio (BCR) was found significantly higher (p˂0.05) in T1 (0.73±0.01) than T2 (0.66 ±0.01), T3 (0.56±0.00) and T4 (0.43±0.02). The overall result indicated that a stocking density of 300 fry/m3 (T1) could be more profitable for Clarias batrachus fry rearing in nursery hapa. J. Bio-Sci. 31(1): 17-27, 2023

Effect of Water Transparency on the Growth of Black Tiger Shrimp,<I>Penaeus monodon</I>

The present study was carried out at "Shrimp Culture Pilot Project", Chandipur coast of Orissa, India, during 1995-1996 to study the role of water transparency on water quality and growth of Penaeus monodon under semi-intensive culture system. It was observed that satisfactory range of average daily growth (ADG) of P. monodon achieved when transparency ranged between 29-35 cm in winter and 30-45 cm in summer. Influence of water transparency on various stages of growth was highly significant (P < 0.01) under semi-intensive culture system. Irrespective of stocking density, high growth rate was mostly obtained during 60-100 days of culture when transparency ranged between 37 ± 8 cm. Growth rate was low at high and low transparency probably due to low nutrient content and high organic load with maximum daily fluctuation of pH (>1.0) and dissolved oxygen (8.1-10.6 mg/1), respectively.

Bacterial Diversity and Antibiotic Resistance Genes Associated with the Different Farming Systems of Black Tiger Shrimp (Penaeus monodon) in Bangladesh

Microbial community inhabiting the intestine of the shrimp (Penaeus monodon) and their surrounding environments (e.g., water and sediment) is considered as a key contributing factor for the sustainable farming of shrimp. Indiscriminate application of antibiotics in aquaculture is a growing concern due to the emergence of antibiotic resistant bacteria (ARB), more specifically the antibiotic resistance genes (ARGs). The present study investigates the microbiome composition and 19 ARGs from four different shrimp farming systems; (i) cluster, (ii) extensive, (iii) semi-intensive, and (iv) improved extensive in the southwest coastal region of Bangladesh. In doing so, the study applied advanced 16S rRNA-based metagenomic sequencing to study the bacterial composition. Moreover, gene specific polymerase chain reaction (PCR) was employed to detect the ARGs in shrimp, water, and sediments of different farming systems. In the current study, bacteria from the phylum Proteobacteria and Firmicutes were predominant among the samples (n = 12) collected from the different farming systems followed by Actinobacteria, Bacteroidetes, and Cyanobacteria. Firmicutes was the predominant phylum in the gut of shrimp cultured in the cluster (relative abundance 53.33%) and semi-intensive (relative abundance 59.2%) culture systems. Results indicated that the bacterial community structure was significantly ( p < 0.05 ) distinct among gut, sediment, and water samples as well as the farming systems. The shared operational taxonomic unit (OTU) in the sediment sample (16,495) was nearly double than the gut (7,931) and water (8,513) bacterial communities. The improved extensive farming system showed 1,289 (11.05%) shared OTUs among gut, sediment, and water followed by semi-intensive (6.87%), cluster (6.27%), and extensive (5.46%) farming system. Among the tested ARGs, sul1, cat, gyrA(C), tetA, tetC, tetX, ere(A), vanR, and dfrA1 were predominant in water and sediment samples. Semi-intensive farming system had the highest prevalence of ARGs (21.05%) while the lowest prevalence was found in extensive (5.26%) farming system. Overall, the study provides a comprehensive scenario of bacterial composition and growing emergence of ARGs in shrimp farming of Bangladesh. Therefore, the production strategy must focus on the alternatives of antibiotic for shaping the shrimp cultivation technique more sustainable.

Determining the efficacy of ginger Zingiber officinale as a potential nutraceutical agent for boosting growth performance and health status of Labeo rohita reared in a semi-intensive culture system

A 120-day feeding trial was conducted in a pilot field setting to study the nutraceutical properties of ginger powder (GP), focusing on the growth performance and health status of Indian major carp L. rohita reared under a semi-intensive culture system. L. rohita fingerlings (average weight: 20.5 g) were divided into five groups and fed a diet with no GP supplementation (control), or a diet supplemented with GP at 5 g (GP5), 10 g (GP10), 15 g (GP15), and 20 g (GP20) per kg of feed. The study was carried out in outdoor tanks (20 m2) following a complete randomized design with three replicates for each experimental group. Dietary supplementation of GP at 15 g·kg−1 (GP15) of feed caused a significant increase in the growth performances of the fish. Results also showed that feeding of GP15 diet led to a significant improvement in the health status of fish as indicated by a marked change in the tested haematological indices (i.e., higher RBC, WBC, Hb, and Ht values), oxidative status (increased SOD and decreased LPO levels), biochemical parameters (increased HDL, decreased cholesterol, and triglycerides levels), and activities of the liver enzymes (decreased AST and ALT). Overall results suggested that dietary supplementation of GP could positively influence the growth and health status of L. rohita fingerlings, and hence could be an important natural nutraceutical for sustainable farming of carp.

Oral feed-based administration of Lactobacillus plantarum enhances growth, haematological and immunological responses in Cyprinus carpio

The effect of probiotic bacteria (Lactobacillus plantarum isolate FLB1) on the immunological responses of Cyprinus carpio (Common carp) was tested in a feeding trial. Fingerlings were divided into five treatment groups and fed with graded probiotic diets [@ 0 (T1), 106 colony-forming unit (CFU)/g (T2), 107 CFU/g (T3), 108 CFU/g (T4), and 109 CFU/g (T5) of test meal] in triplicate. Fish fed probiotic supplemented diets had significantly (P < 0.05) improved growth performance, haematological parameters, blood Haemoglobin (Hb), Total Erythrocyte Count (TEC), Total Leucocyte Count (TLC), Packed Cell Volume (PCV)/ Hematocrit (Ht), Mean Corpuscular Haemoglobin (MCH), and Mean Corpuscular Haemoglobin Concentration (MCHC), with the greatest improvement in the treatment T5. Significant (P < 0.05) increase in total serum protein and globulin, as well as lower Albumin (Alb)/ Globulin (Glb) ratio values were also reported. These values indicated the overall improvements in non-specific immune markers. In all the probiotic fed fish groups, significantly (P < 0.05) reduced values of blood glucose levels, total cholesterol, Triglycerides (TG), and High-Density Lipoprotein (HDL) were observed. Increased numbers of lactic acid bacteria (LAB) were detected in the gastrointestinal tract of probiotic-fed groups indicating the viability and survival of L. plantarum in the fish gut. The results showed that supplementing the diet with L. plantarum @ 109CFU/g feed during the growth period of the fish in a semi-intensive culture system could improve growth and health status of C. carpio.

Choline Chloride Induces Growth Performance of Indian Major Carps and Air-Breathing Fish Species with an Outcome of Quality Food-Fish under a Semi-Intensive Culture System: A Biochemical Investigation.

The present study was intended to determine the possible influences of direct field application of choline chloride into pond water in addition to farm-made-aqua-feed under a semi-intensive culture system on the growth and biochemical parameters of two Indian major carps (IMCs), Catla catla (Catla) and Labeo rohita (Rahu), and two air-breathing species, Clarias batrachus (Magur) and Anabas testudineus (Koi), cultured in a ratio of 2:5:1:1 (Catla/Rahu/Magur/Koi) in three experimental ponds for a period of 90 days during the breeding season (June to August). Results were compared with control (C: fed only with farm-made-aqua-feed) and treatment (T: P1 and P2: farm-made-aqua-feed plus choline chloride into pond water directly at the rate of 350 g bigha–1 fortnightly or 350 g per 1600 square meter fortnightly). A significant increasing trend was observed in the growth parameters including total length-final (TLF), standard length-final (SLF), mean weight-final (MWF), % gain of mean total length (MTL), % gain of mean standard length (MSL), % weight gain (WG), specific growth rate (SGR) % per day, and survivability %. However, a reverse pattern was noticed in the food conversion ratio (FCR) both in IMCs and air-breathing fish species under choline supplementation. Serum biochemical responses, e.g., total protein (PRO), lactate dehydrogenase (LDH), glucose (GLU), and calcium (Ca) showed significant enhancement, and alkaline phosphatase (ALP), alanine amino transaminase (ALT), aspartate amino transaminase (AST), cholesterol (CHOLES), and triglycerides (Trig) showed gradual significant reduction during the breeding season under choline exposure. Treated fishes showed prevention from liver dysfunction and fatty liver formation, and increased body crude protein content. Results indicated favorable growth and yield, which may benefit fish farmers during their culture practices, and the output fish species under choline supplementation resulted in quality food-fish for human consumption.

High protein krill meal as a tool to optimize low cost formulas for juvenile Litopenaeus vannamei diets farmed under semi-intensive conditions

ABSTRACT To investigate the potential of high-protein krill meal (HPK) to improve growth in low-cost diets for Pacific white shrimp (Litopenaeus vannamei), a commercial control and a 3% HPK diet were compared. To simulate a semi-intensive culture system, a total of 4,500 shrimp with a body weight (BW) of 3.07 ± 0.01 g were stocked with 25 animals/m2 in 20 cages in a 2.16-ha pond. After 60 days of rearing, the 3% HPK diet achieved a significantly higher yield (22,094.0 ± 130.35 g/cage) in comparison to the control diet (19,301.6 ± 272.28 g/cage) (P < 0.05). When the feed cost per kg shrimp produced was compared, it was significantly lower in the 3% HPK group (US$1.01/kg shrimp) when compared to the control group (US$1.11/kg shrimp). The results indicate that low feeding cost diets can profit from the partial replacement of fish meal by HPK to optimize shrimp growth performance without increasing formula cost.

Potential adaptation strategies for climate change impact among flood-prone fish farmers in climate hotspot Uganda

Climate-induced floods are increasing in Africa. The need to evolve framework for adaptation to climate change impact (CCI) among flood-prone fish farmers necessitated this study. Based on availability, 60 farming active flood-experienced fish farmers were purposively selected from flood-prone (Gulu and Kibuku) regions in climate hotspot Uganda. These were assessed for CCI adaptation tendencies in their socioeconomics and farming operation/techniques (FOI) indices, CCI awareness, CCI adaptation strategies, and perceived required interventions (RIs) using structured questionnaire. Data were analyzed through descriptive and multivariate regression tools. Respondents were mostly male, adults, educated, Christian, married, medium-sized family, social group members, 1–5 years’ experience, medium-sized farms, and government trained. Income was 1.0–6.0 million Ugx/year. In FOI, semi-intensive culture system, use of rainwater plus groundwater, small-sized (< 0.5 ha) ponds, ponds possession of inlets and outlets, seasonal farming and mixed culture/farming dominated. Most respondents were aware of CCI, while erratic rainfall with floods and prolonged drought mostly impacted farming. AS-Adaptation Strategy were changed stocking time and livelihood diversification. Communication technology and social group’s membership enhanced adaptation, while inadequate awareness constrains adaptation. Respondents’ RI(s) were tree planting, irrigation and pond perimeter trenching. Gender, government training, farm size, water sources and presence of inlet and outlets in ponds (FOI) predicted adaptation (R = 0.802, R2 = 0.64, P < 0.05). Some socioeconomic, technical and awareness indices could assist CCI flexibility. However, the statistically significant predictors of adaptation, identified adaptive strategies, constraints to adaptation and required interventions could be integrated into a framework for effective CCI adaptation for sustainable fish farming in flood-prone scenarios.

Evaluation of commercial application of dietary encapsulated probiotic (Geotrichum candidum QAUGC01): Effect on growth and immunological indices of rohu (Labeo rohita, Hamilton 1822) in semi-intensive culture system

Encapsulated probiotic administration can be a nutritional strategy to improve the growth performance and immune status of fish. Here commercial application of encapsulated G. candidum was evaluated as a feed supplement to fingerlings of L. rohita reared in earthen ponds under semi-intensive culture conditions. Fingerlings with an average body weight of 20 ± 2.34 g were distributed randomly in three groups and experiment was conducted in triplicate. The control group (P0) was fed 35% protein basal diet while the two treated groups, P1 and P2 were fed basal diet supplemented with 109 CFU g−1 un-encapsulated (free) and encapsulated G. candidum, respectively, for eleven weeks. Results indicated significantly (P < 0.05) improved growth rate, intestinal enzyme activities (protease, amylase and cellulase) and hemato-immunological indices (RBCs, Hb, HCT, WBCs, MCHC, respiratory bursts and phagocytic activity, total protein, lysozyme, IgM), upregulation of heat shock protein HSP 70 gene in muscle, intestine and liver tissues and reduction of serum AST and ALT activities, total cholesterol and triglyceride in fish fed G. candidum supplemented diets (P1 and P2 groups) as compared to basal diet (P0 group). However, diet supplemented with encapsulated G. candidum showed the most significant (p < 0.001) positive effect in comparison to un-encapsulated probiotic. In conclusion, a pronounced effect of G. candidum especially in the encapsulated form on the growth, health status and immunity of L. rohita reared in semi intensive culture system, suggesting its application as a feed additive in practical/commercial semi-intensive earthen pond culture system.

Exclusion of two microsatellite markers in the sex-linkage study of Nile tilapia (Oreochromis niloticus L.)

Monosex Nile tilapia (Oreochromis niloticus) is highly preferred in semi-intensive and intensive culture systems to prevent uncontrolled reproduction and to obtain fast growing male. Production of all male tilapia is being practiced by the hatcheries of Bangladesh mainly by administering androgen hormones (particularly 17-α-methyl-testosterone) with feed in a mixture of undifferentiated fry for about a month. The direct application of hormone to such food chain often arises question in respect to public health and safety. The alternative to this is the production of putative supermales, a rather safe but longer procedure to obtain all male progeny. However, sex determination system in tilapia is fairly complex. Recent developments have resulted in a linkage map and genetic markers that can be used to analyze the sex determination system. For genetic analysis of different genotypes of fish, microsatellite DNA marker ARO120 and ARO121 were used for studying the inheritance pattern for possible sex linkage using Polyacrylamide gel electrophoresis. In case of ARO120, it was observed that the Dam XX was heterozygous; 11 out of 22 female progeny and 10 out of 22 male progeny were found to be heterozygous. In case of ARO121, it was observed that the Dam XX was heterozygous; 16 out of 22 female progeny and 20 out of 22 male progeny were found to be heterozygous. Though the marker polymorphisms were observed in this study, these were excluded from the sexlinkage study due to limited extent of information as sex-linked markers in Nile tilapia BFRI strain. This study provides a baseline for further research using other suitable polymorphic markers for assisting marker-assisted selection.&#x0D; Res. Agric., Livest. Fish.6(1): 143-151, April 2019

Effect of varying dietary protein levels on the growth response of Labeo rohita (Rohu) fingerlings under semi-intensive culture system

Effect of varying dietary protein levels on the growth response of Labeo rohita (Rohu) fingerlings under semi-intensive culture system

Proximate and fatty acid composition of 13 important freshwater fish species in central Europe

We aimed to investigate proximate and fatty acid composition of important freshwater fish species in the Czech Republic. Sampled fish include seven species from intensive farming: African catfish, rainbow trout, Wels catfish, Nile tilapia, brook trout, northern whitefish, and pikeperch; eight species from semi-intensive culture systems: common carp, northern pike, pikeperch, grass carp, European perch, tench, silver carp, and catfish; and three species from extensive culture systems: rainbow trout, tench, and common carp. The fat content and fatty acid composition were highly influenced by the culture systems. Simultaneously, we observed a significant dependence of fatty acid composition on the fat content. The content of saturated fatty acids was below 34% in all analyzed fish. Northern pike, pikeperch, and European perch contained with over 50% the highest proportion of polyunsaturated fatty acids. Intensively cultured fish reached the highest content of eicosapentaenoic and docosahexaenoic fatty acid. Nutritional quality was determined by atherogenic and thrombogenic indexes which ranged from 0.27 to 0.63 and 0.20 to 0.61 and by ratios n-3/n-6 (0.54–3.45) and polyunsaturated/saturated fatty acids (0.67–2.01). Results demonstrated that the flesh of all studied species are of high nutritional quality.

Occurrence of white spot syndrome virus and Vibrio parahaemolyticus in brackishwater shrimp culture systems of Sundarban, West Bengal, India

White spot disease (WSD) and acute hepatopancreatic necrosis disease (AHPND) are two important and highly fatal diseases of cultured shrimps. The occurrence of white spot syndrome virus (WSSV) was found to be very high in brackishwateraquaculture systems of Sundarban area in West Bengal, with 40.6% of the samples being positive of which 18.75% being positive in the first step PCR. The prevalence of WSSV in traditional and semi-intensive culture systems was foundas 59.3 and 27%, respectively. On the other hand, presence of Vibrio parahaemolyticus was detected in 53.1, 55.5 and 75.9% of the shrimp, water and soil samples, respectively. All the isolates of V. parahaemolyticus contained toxR gene as detected by PCR. However, none of the isolates was realised as AHPND causing isolate by PCR. Moreover, tdh gene, which causes gastroenteritis in human beings, was also not detected in any of the isolates. The present study indicated that WSSV is the major cause of crop failure in the brackishwater shrimp culture systems of Sundarban, India. Although,V. parahaemolyticus is highly prevalent in brackishwater shrimp culture systems of Sundarban, strains causing gastroenteritis or AHPND were not detected during the present study.

Effects of water physico-chemical parameters on tilapia (Oreochromis niloticus) growth in earthen ponds in Teso North Sub-County, Busia County

Small-scale fish farmers in developing countries are faced with challenges owing to their limited information on aquaculture management. Nile tilapia farmers in Teso North Sub-County recorded lower yields than expected in 2009 despite having been provided with required inputs. Water quality was suspected to be the key factor responsible for the low yields. This study sought to assess the effects of earthen pond water physico-chemical parameters on the growth of Nile tilapia in six earthen fish ponds under semi-intensive culture system in Teso North Sub-County. The study was longitudinal in nature with pond water and fish being the units of analysis. Systematic sampling was used to select five ponds while a control pond was purposively selected based on its previously high harvest. Four ponds were fed by surface flow and two by underground water. Each pond was fertilized and stocked with 900 fry of averagely 1.4 g and 4.4 cm. Physico-chemical parameters were measured in-situ using a multi-parameter probe. Sixty fish samples were randomly obtained from each pond fortnightly for four months using a 10 mm mesh size and measured, weighed and returned into the pond. Mean range of physico-chemical parameters were: dissolved oxygen (DO) 4.86–10.53 mg/l, temperature 24-26 °C, pH 6.1–8.3, conductivity 35–87 μS/cm and ammonia 0.01–0.3 mg/l. Temperature (p = 0.012) and conductivity (p = 0.0001) levels varied significantly between ponds. Overall Specific Growth Rate ranged between 1.8% (0.1692 g/day) and 3.8% (1.9 g/day). Ammonia, DO and pH in the ponds were within the optimal levels for growth of tilapia, while temperature and conductivity were below optimal levels. As temperature and DO increased, growth rate of tilapia increased. However, increase in conductivity, pH and ammonia decreased fish growth rate. Temperature and DO ranging between 27 and 30 °C and 5–23 mg/l, respectively, and SGR of 3.8%/day and above are recommended for higher productivity.

Effect of periphyton (aquamat) on water quality, nitrogen budget, microbial ecology, and growth parameters of Litopenaeus vannamei in a semi-intensive culture system

The present study was conducted to evaluate the role of periphyton in the improvement of water quality, released effluents, microbial ecology and growth parameters of Litopenaeus vannamei in a semi-intensive aquaculture system. The experiment was performed for 120days in 0.66ha pond with and without addition of substrate i.e. treatment (periphyton based) and control pond (feed based), respectively having a stocking density of 20m−2 (PL 15). The significant (P<0.05) reduction in concentration of total ammonia nitrogen (TAN), nitrite-N, and biological oxygen demand (BOD) were found in substrate treated pond when compared with the control. About 39 genera of phytoplankton belonging to Bacillariophyceae (14 genera), Chlorophyceae (12 genera), Cyanophyceae (10 genera) and Euglenophyceae (3 genera) were found adhered on aquamat. Significant (P<0.05) improvement in the growth parameters of L. vannamei and feed utilization (FCR=1.02) were recorded in the substrate treated pond when compared to control (FCR=1.31). At the end of the experiment, a significant reduction (12%) in the concentration of nitrogen present in the effluents (output water) was estimated in substrate treated pond. Significantly low level of nitrogen content was estimated in the sediment of substrate treated pond when compared with the control. Nitrogenous waste generated for producing one ton of shrimp, got reduced by 25% in the periphyton based aquaculture pond. Moreover, a significantly (P<0.05) low total Vibrios counts (1.14×103CFU mL−1) were enumerated when compared with the control pond (1.53×103CFU mL−1) and ratio of total Vibrios counts (TVC) to total heterotrophic bacteria (THB) in the water of substrate treated pond and control was found to be 10.56 and 28.39, respectively. Higher survival rate (93%) of L. vannamei was recorded in the substrate treated pond in comparison to the control (84.4%). In general, addition of substrate to obtain periphyton significantly reduced nitrogenous waste in the effluent, by converting it into heterotrophic bacterial and algal biomass, improved the culture water quality and growth parameters and survival of the shrimp in comparison to the normal feed based aquaculture system. Statement of relevanceTo evaluate effect of periphyton (aquamat) on water quality, nitrogen budget, microbial ecology and growth performance of Litopenaeus vannamei in a semi-intensive aquaculture system.

Productivity and economics of rotated culture of Nile tilapia (Oreochromis niloticus) fingerlings with wheat and clover under semi-intensive culture system in earthen ponds

Productivity and economics of rotated culture of Nile tilapia (Oreochromis niloticus) fingerlings with wheat and clover under semi-intensive culture system in earthen ponds

Survival and growth of Litopenaeus vannamei reared in Bft System under different water depths

Shrimp farming has recently pursued systems that minimize the use of water. A biofloc technology (BFT) culture system contributes to water quality by removing nitrogen compounds, supplementing the shrimp diet and allowing for the use of high stocking densities. In addition, this system enables the culture with minimal water exchange. This study raised Litopenaeus vannamei shrimp in a BFT system at different water depths. Three treatments were compared at 0.40, 0.80 and 1.20m of water depth (salinity 30). Treatments were randomly assigned to nine 35,500L lined tanks in a greenhouse. Each tank was stocked with 14,000 animals (400shrimpm−2). Feed (38% crude protein - CP) was provided three times per day via feeding trays. The study lasted 120days. The water quality parameters, weight gain, FCR and survival were evaluated. No significant differences were detected for water quality parameters (P>0.05) except for alkalinity, which was higher in the 1.20m treatment (P<0.05). The final weight and survival did not show significant differences (P>0.05). Final biomass (kgm−3) was significantly higher in the 0.40m treatment (P<0.05). The productivity levels were 2.88 (1.2m), 4.83 (0.80m) and 8.45kgm−3 (0.40m) at 17weeks. The 0.40m treatment used 119L of water to produce 1.0kg of shrimp. Based on the results, decreasing the depth of the shrimp tanks to 0.4m increases the productivity and decreases the use of water per kilogram of shrimp produced. Statement of relevanceIn the last few years, several researches have been developing technologies to improve Aquaculture production. Shrimp culture achieved high levels of productivities, mainly in semi intensive culture systems in subtropical areas around the world. However, environmental impacts and shrimp diseases have been worldwide spread. In addition, the effluent from aquaculture rich in organic materials and nutrients can cause environmental pollution as well as expenses with pumping water. Thus, the shrimp culture has been directed to biosecurity systems that minimize the use of water. The new proposed culture system, Biofloc Technology Culture Systems (BFT) is characterized by zero water exchange and super-intensive culture of shrimp in enclosed raceways. This system is considered environmentally friendly and avoids nutrient rich waste from polluting coastal waters. The nutrients transformation in biofloc (microorganisms) contribute to the water quality, through the removal of nitrogen compounds, supplements the shrimp diet and allows the use of high stocking densities. Depth as a factor in pond ecosystem management has been given little attention, despite its theoretical importance in autotrophic and heterotrophic systems. Besides of this, the shrimp behavior and water quality parameters could be completely changed according to the amount of water available in the culture system. Therefore, the objective of this study was to compare the growth performance of Litopenaeus vannamei in greenhouse-enclosed raceways with different depths, in BFT culture system. According to the results, water quality parameters were within recommended ranges for shrimp health in terms of dissolved oxygen, pH, temperature and salinity in different depths. The same was detected for nitrification process. Anyway, the amount of water used to produce 1.0kg of shrimp ranged from 119 to 352L. The best result was in 0.4 treatment with the production of 8.45kgm−3. Therefore, according to the results from the present study, decreasing the depth of shrimp tanks to 0.4m increases the productivity and decreases the use of water per kilogram of shrimp produced.

The Prospects of Analysing the Environmental Impacts of Egyptian Aquaculture Using Life Cycle Assessment

Aquaculture is the fastest growing food producing sector. It accounts for nearly 50% of the world food fish. It plays an important role in the economy, providing thousands of jobs for farm technicians and skilled labor. Furthermore, new industries and financial services in support of aquaculture are also providing employment opportunities. In Egypt, very rapid developments have occurred as well. Egypt's aquaculture production (1097544 tonnes in 2013) is by far the largest of any African country and places it 9th in terms of global aquaculture production. This expansion has been accompanied by a gradual shift from extensive and semi-intensive culture systems to more intensive feed dependent system. Although the importance of aquaculture is often understated, the consequent implications on the environment are difficult to ignore. Life cycle assessment (LCA) is a useful tool to improve the understanding of the contribution of different production systems to regional sustainable development. Increasing number of LCA studies of aquaculture have been published. The current study reviews the different LCA approaches in both global and regional aquaculture industry focusing on type of studies, production systems and considered environmental impacts. It also, identifies focus points required for future investigations.

Impact of stocking density on growth and production performance of Vietnamese koi (Anabas testudineus) in semi-intensive culture system at Muktaghasa region of Mymensingh district

Stocking density is considered one of the important factors affecting fish growth. The study was aimed to compare the growth parameters of Vietnamese Koi (Anabas testudineus ) at various stocking densities. The experiment was carried out during the period from 01 September to 30 November 2014. Three stocking densities were used as 150, 250 and 350 fries/dec and designated as treatment T1, T2 and T3 respectively each having two replicates. The average size of each pond was 33 decimal with an average depth of 5 feet. Quality fish feed was used three times daily throughout the culture period. From this experiment, it was found that the highest net profit was BDT 32,690 in T1 followed by BDT 36,104 in T2 and BDT 38,450 in T3. That time the market price was BDT 130/kg fish. Culture of Vietnamese koi at stocking density (150 fish/dec) showed higher benefit in short period of time. The benefit cost ratio was 1.7, 1.63 and 1.56 in T1, T2 and T3, respectively. From the present experiment, it was found that the total production was increased with the increase of stocking density. But the individual fish growth rate was decreased with the increase of stocking density.Res. Agric., Livest. Fish.2(2): 335-341, August 2015