Tilapia Farming Research Articles

Waterbody scale assessment using spatial models to identify suitable locations for cage aquaculture in large lake systems: A case study in Volta Lake, Ghana

Large lakes throughout the world offer development opportunities for cage aquaculture. However, due to their vast area, identifying the most suitable locations can be a challenge. This is also complicated as lake systems are often multi-use environments, so a strategic approach to managing the resource is required. This study uses geographic information systems (GIS) to develop a broad-scale approach that identifies potential areas that may be suitable for cage aquaculture development. Volta Lake, one the world's largest man-made lakes, is used as a case study. The overall GIS model combines four sub-models, bathymetry, hydrography, water quality and access, and a constraints layer, to identify the most suitable locations for tilapia production. Three different cage sizes are modelled: small, medium and large. The model outputs suggest that approximately 102 km2 (1.7%), 406 km2 (6.9%) and 407 km2 (6.9%) of Volta Lake can be categorized as highly suitable for development of small, medium and large cages respectively. A further 634 km2 (10.8%), 1264 km2 (21.4%) and 1055 km2 (17.9%) can be categorized as suitable for the same. The results can be used by stakeholders and decision makers to identify specific areas where aquaculture development for cage farming of tilapia could be prioritized.

All-male production by marker-assisted selection for sex determining loci of admixed Oreochromis niloticus and Oreochromis aureus stocks.

Crossing Oreochromis niloticus (On) females with Oreochromis aureus (Oa) males results in all-male progeny that are essential for effective tilapia farming. However, a reproductive barrier between these species limits mating and mass-fry production. One approach to overcoming this barrier is to select parental stocks of mixed genetic backgrounds, which allow interspecific reproductive recognition, while closely maintaining the genetic profiles for sex-determination (SD) of the respective purebred species. Here, we test this approach in a data set of 160 On×Oa spawns of 109 male and 100 female parents randomly collected from admixed stocks, and genotyped for microsatellite markers representing the known SD loci on linkage groups (LGs) 1, 3, and 23. Following crossbreeding, the most significant paternal effects on male proportions in progeny were found for LG1-BYL018 (P<2×10-32 ) and for LG3-UNH168×LG23-UNH898 interaction (P<1×10-17 ; R2 =0.98). Furthermore, a maternal effect for LG3-UNH168 (P<9×10-7 ) was associated with low female proportions in progeny (<7%), indicating a non-Mendelian effect on SD. Eighty-four males (77%) and 30 females (30%) were selected as parents, based on their genetic profiles for the SD loci that were associated with male production. Of these, 51 of 53 crosses produced all-male progeny, while two crosses had low female proportions in their progeny (<4%). This suggests that selection could be improved using the causative sequence variation underlying SD on LG3, since the large non-recombining block of the SD region in purebred Oa readily breaks down in hybrids. Nevertheless, marker-assisted selection for sex determining loci of admixed parental stocks may be used for all-male production.

Poverty and vulnerability assessment of tilapia farmers in the southwestern States of Oaxaca, Guerrero, and Chiapas in Mexico

This study assessed the impact of tilapia farming on poverty in the States of Oaxaca, Guerrero, and Chiapas, which have the highest levels of poverty in Mexico. The study uses both 2018 data from a sample of micro- and small-sized farmers in these States, and the Mexican government’s multidimensional poverty methodology. Results show fewer tilapia farmers in extreme or moderate poverty compared to the general population’s value in the municipalities and States where these farms are located, therefore asserting the positive impact of the activity. While cage farmers have more social rights deprivations, their income is greater compared to that of tank and pond farmers. Tilapia projects are also relevant to food security, increasing both household fish and animal-protein consumption.

Peracetic acid treatment of Ichthyophthirius multifiliis (Ciliophora: Ichthyophthiriidae) and Trichodina spp. reduces the infection by Aeromonas hydrophila and improves survival in Nile tilapia (Oreochromis niloticus)

Co-infections with ectoparasites and bacteria commonly occur in fish farms and are associated with high mortality. In March 2020, a private Nile tilapia (Oreochromus niloticus) farm in Sharkia Governorate, Egypt, experienced high fish mortality, and the clinically diseased fish were characterized by lethargy, abnormal swimming behavior, loss of appetite, skin hemorrhages, exophthalmia, and abdominal distension. Laboratory parasitological and bacteriological examinations of the diseased fish revealed concurrent infections with Ichthyophthirius multifiliis, Trichodina centrostrigeata, and Aeromonas hydrophila. Pathological findings indicated severe gill and skin infections with I. multifiliis and T. centrostrigeata associated with necrosis, hemorrhages, and depletion of the hemopoietic organs, as well as cardiac inflammation. Peracetic acid (PAA) was applied as a strong oxidizing antimicrobial disinfectant, and in vitro evaluation showed that 5 ppm achieved 5-log reductions in the viable colony count of A. hydrophila after a contact time of 5 min and 1.076 ppm represented the 4-h 50% lethal concentration (LC50) for the infective stage of I. multifiliis (theronts). The continuous exposure of culture water to 1 mg L−1 PAA for 1 week followed by periodical use of PAA at the same concentration twice per week was effective in eradicating the ciliated protozoans, reducing the aerobic bacterial density in water, ameliorating the pathological alterations, restoring the fish health, and reducing the mortality rate by up to 15%. Thus, the use of PAA to treat I. multifiliis and T. centrostrigeata reduces the infection by A. hydrophila in Nile tilapia and improves their survivability.

Towards the Integrated Agri-aquaculture in the Desert Using Groundwater Reservoirs for Plants and Nile Tilapia Farming "Evaluating Study in Upper Egypt".

Towards the Integrated Agri-aquaculture in the Desert Using Groundwater Reservoirs for Plants and Nile Tilapia Farming "Evaluating Study in Upper Egypt".

Negative effect of ectoparasite burdens on the condition factor from farmed tilapia Oreochromis niloticus in the Yucatan, Mexico

Nile tilapia (Oreochromis niloticus Linnaeus, 1758) is one of the most important aquaculture species in the world, and, when introduced, the ectoparasites of Nile tilapia have followed. Currently, farmers worldwide consider these ectoparasites harmless, but intensities can reach up to 1000 individuals per fish in tropical regions. In this cross-sectional study, we used the condition factor to estimate the potential effects of low (45 ± 31 ectoparasites per fish) and high (295 ± 191) ectoparasitic burdens across 28 tilapia farms and included the analysis of the effects of 44 management and environmental variable from the farms. A stepwise procedure in a multiple linear regression analysis retained the variables that explained the most variance, which was the ectoparasitic burden (57 %). We found significantly higher values of the condition factor in Nile tilapia with low ectoparasitic burden than in those with high ectoparasitic burden. Additionally, Nile tilapia with a high ectoparasitic burden weighed less than half than those with a low burden (102 ± 105 g versus 230 ± 128 g, respectively). We also found a significant non-linear, negative relationship between the ectoparasitic burden and the relative condition factor values per fish, which was most likely due to an increase in gill mucus caused by the ectoparasitic burden that depleted energy in the Nile tilapia. The economic consequence of the ectoparasitic burden translated roughly into a loss up to 12–15 % in profit margin per ton of fish, based on the price of Nile tilapia in the Mexican market.

Genomic selection for resistance to Francisellosis in commercial Nile tilapia population: Genetic and genomic parameters, correlation with growth rate and predictive ability

Nile tilapia has become the most important species within freshwater aquaculture worldwide, the global tilapia market being expected to reach US$ 25 billion before the end of 2028. Since on an average 50% of the biomass is being lost during outbreaks of Francisellosis in tilapia farms, this study was undertaken to estimate the genetic parameters for resistance to this economically important disease of Nile tilapia, and calculate the genetic correlation with body weights at different ages. A further aim was to characterize the potential of, and to select the best genomic model for, the implementation of genomic selection for resistance to Francisellosis in the commercial Nile tilapia breeding program. The study revealed moderate to high heritabilities (0.37 ± 0.05 to 0.51 ± 0.06) for resistance to Francisellosis using both pedigree and genomic-based estimates. The genetic correlation between resistance to Francisellosis and five different growth traits at different ages ranged from −0.09 to −0.29. Compared to pedigree-based models, GBLUP was found to increase the predictive ability for resistance to Francisellosis by 57%, and the use of Bayesian models would increase this predictive ability by up to 217% in the practical breeding scenario. Thus, the study shows the potential to increase resistance to Francisellosis by genetic selection in commercial Nile tilapia breeding programs. The genetic correlation between resistance to Francisellosis and growth traits showed negative trends, although they were significantly not different from zero. A very large increase in predictive ability for resistance to Francisellosis can be achieved by using Bayesian models for genomic selection.

The effects of tryptophan supplementation on stress and aggression in Nile tilapia

Nile tilapia farmers must deal with production challenges, such as increased aggressiveness and high stress levels, which potentially diminishes fish welfare. Tryptophan supplementation is a strategy to cope with such problems. However, data is scarce on how tryptophan affects the aggressiveness of this species and other aspects need to be understood on how it influences stress in fish. In this study, we investigate how a 1× (0.32%), 4× (1.28%) and 8× (2.56%) supplemented tryptophan diet affects aggressiveness and stress in Nile tilapia. Aggressiveness in fish was assessed after short-term exposure (7 days) to a tryptophan supplemented diet while stress in fish was assessed after long-term exposure (60 days). The 4x and 8x diets reduced aggressiveness in fish, while the 8x diet reduced aggressiveness more effectively than the 4x diet. Also, long-term exposure to the 8x diet reduced stress in fish, before and after they were exposed to an acute stress. In conclusion, this study showed that a tryptophan supplemented diet can diminish aggressiveness and stress in Nile tilapia, thus demonstrating a potential to improve fish welfare.

The effectiveness combination of maggot (Hermetia illucens) flour with commercial feed on growth rate, feed conversion ratio, and feed efficiency of tilapia (Oreochromis niloticus)

Tilapia (Oreochromis niloticus) is a freshwater fish commodity that has high economic value. One way to increase tilapia production is to conduct intensive culture efforts by providing artificial feed. However, an important problem in tilapia farming is the high price of commercial feed. One way to reduce the cost of producing expensive commercial feed is by utilizing alternative raw materials that are easily available. Maggot flour is an alternative raw material that has high nutritional value ranging from 30-45% at a cheaper price. This study aims to determine the addition of maggot flour to commercial feed can increase the growth rate and feed efficiency, and reduce the feed conversion ratio of tilapia. The method was experimental with a completely randomized design (CRD) as an experimental design. This research used five treatments and four repetitions consisting of P0 (0%), P1 (24%), P2 (49%), P3 (74%) and P4 (94%). The results showed that the addition of maggot flour to commercial feed had no effect (p> 0.05) on growth rate, feed conversion ratio, and feed efficiency of tilapia. The concentration of adding maggot flour which can produce values of growth rate, feed conversion ratio, and feed efficiency of tilapia is 24%.

Application of the FTA elute card coupled with visual colorimetric loop-mediated isothermal amplification for the rapid diagnosis of Streptococcus agalactiae in farmed tilapia (Oreochromis niloticus).

A method combining the FTA Elute card and visual colorimetric loop-mediated isothermal amplification (FTA-e/LAMP) was tested to diagnose Streptococcus agalactiae infections in vitro and in vivo. FTA-e/LAMP consists of two main steps: first, the FTA card is used to extract DNA and then a colorimetric loop-mediated isothermal amplification (LAMP) reaction is carried out on the extracted DNA. In vitro sensitivity was 1.9x102 CFU/mL, and regarding specificity, all nine S.agalactiae strains tested positive. All Streptococcus spp. tested negative, except for S.dysgalactiae, thereby indicating the need for another set of primers to distinguish this species from S.agalactiae. To diagnose S.agalactiae infections using FTA-e/LAMP in vivo, two experimental trials on juvenile Oreochromis niloticus infected with bovine or piscine strains were carried out. Sensitivity in symptomatic fish was 100%, and 50.7% of fish without signs were positive. All negative control fish tested negative (n=28). No bacteria were detected after 16days post-infection (dpi). Accuracy during the first week (1-7dpi) was 89% and decreased to 44% thereafter (10-22dpi). FTA-e/LAMP results suggest that this method is a promising tool for early and fast diagnosis of S.agalactiae on tilapia farms.

Mortality rate of newly hatched larvae of Nile tilapia (Oreochromis niloticus) submitted to different photoperiods

ABSTRACT: Fish farming is a growing area in the aquaculture industry. Brazil is among the five largest tilapia producers in the world, with a production of 283 thousand tons in 2017. Tilapia has been intensively cultivated and improved through more efficient cultivation techniques. In this sense, the objective was to evaluate the mortality rate of newly hatched larvae of Nile tilapia reared three photoperiods (12Light:12Dark, 18L:06D, and 24L:0D) during 9 days of cultivation. For this purpose, a recirculation system with 9 water tanks was set up, with 3 boxes per group containing 930L of freshwater. After the embryos hatched, the larvae were transferred to nurseries (2 trays per tank, n = 64 larvae/tray), with 384 larvae per photoperiod. Water quality parameters were monitored and remained in the ideal ranges between treatments. However, temperature (p=0.004) and pH values (p= 0.009) for the 18L:06D photoperiod were lower than those observed for the 24L:0D photoperiod. A high mortality rate was observed in the first days of culture, specifically on the second day, for all photoperiods. However, there was a decrease in mortality throughout the experiment, with little variation in the mortality rate for the remainder of the experiment. In this context, it appears that the influence of the photoperiod on the survival of the fish seems to be related to the age of the animal. KEYWORDS: Tilapia farming, Survival, Light stimulation.

Study of the utilization of Azolla microphylla as alternative feed by Tilapia farmers in Panjalu Ciamis, West Java Province, Indonesia

Feed is the most significant component of tilapia culture production costs. Various attempts have been made to reduce this cost with alternative feed, including A. microphylla. The research aims to encourage changes in the level of knowledge, attitudes, and skills of fish cultivators about utilization and cultivation of Azolla through the demonstration ponds (Dempond) and increase the production of tilapia by increasing the stocking density and the use of A. microphylla feed. The research was conducted from March 2nd to May 15th, 2021, in Panjalu Sub District, Ciamis Regency, West Java Province. Data were collected by purposive sampling, with observation and interview methods. The data consists of primary and secondary data. The data analysis was carried out in a descriptive qualitative manner. The results showed a change in fish cultivators' knowledge about the benefits and cultivation of A. microphylla by an average of 20.28%, a change in target attitudes by 5.1%, and skill improvement by 28%. There was an increase in tilapia yield from the initial total weight of 121.25 kg to 226.1 kg using 24 kg of A. microphylla as a feed additive for 60 days of culture.

Effects of high stocking density on survival and growth of Sabaki tilapia Oreochromis spilurus

This study's main objective was to estimate the survival rate and growth performance of grow-out Sabaki tilapia (Oreochromis spilurus, Günther, 1894) at different high stocking density levels: 50, 100, 150, 200 and 250 fish per m3. The experiments were conducted in triplicate and monitored for survival rate and growth performance for an experimental period of 16 weeks. Results indicated that the survival rate was significantly different in higher stocking density groups. The growth performance was not significantly different in each group. Overall, the results indicate that the Sabaki tilapia farming is feasible in high stocking density conditions.

PENGARUH STRATEGI PEMBELAJARAN BERBASIS MULTIREPRESENTASI TERHADAP PENINGKATAN PENGUASAAN KONSEP SISWA KELAS X-A SMA PGRI KOTA JAYAPURA PADA POKOK BAHASAN KALOR

This research was conducted at Emeyedore Vocational High School, Sorong City with a time bracket of two months, the method used was experimental. The results of the Tilapia fish farming "Wanto Group" is one of the tilapia fish farming businesses in Sorong Regency. This business is quite good in every cycle of market needs, but in the last few months (Covid 19) production is less than demand and does not match the results obtained, this mismatch is due to less production of tilapia but market demand is increasing. This obstacle is mainly due to the fact that most of the local fishery business actors are still traditional, with limited facilities and infrastructure and the unavailability of a market for fishery production products. With the problem of tilapia farming, a learning experiment was carried out by involving students in practicum activities.

Temporal trends of tilapia lake virus disease in Israel, 2017-2018.

Tilapia lake virus (TiLV) is an emerging viral disease that affects several tilapia species in different countries since 2014. In 2017-2018, 129 samples were collected from 14 tilapia farms in Israel. Ninety samples represented mortality events (ME), and 39 were used as control samples (CS). RT-qPCR was performed on 89 and 39 duplicate brain and liver tissue samples from ME samples and CS, respectively. TiLV was diagnosed in 37 (41.6%) ME, while only two of the CS samples (5%) were positive for TiLV (OR=13.2, 95% CI=3.0-58.1). Additional RT-PCR was performed on positive samples, and amplified products were sequenced. Maximum likelihood phylogenetic analysis of segment-3 revealed three distinct clades: the first clade (A) includes 25 sequences of TiLV, detected previously in Israel (2011), Ecuador (2012), Egypt (2015), Thailand (2015-2019), India (2017), Peru (2018) and USA (2018-2019) and 11 sequences of TiLV from the current study (2017-2018); the second clade (B) includes only four sequences from Thailand (2018) and Bangladesh (2017 and 2019); and a third clade (C) which includes a single sequence from Bangladesh (2019). Out of the 39 sequences included in clade A, 14 closely related sequences of TiLV from the current study (2018) formed a distinctive sub-clade (IL-2018). Mann-Whitney U test showed differences in the distribution of survival rates between Israeli sequences (from 2011, 2017 and 2018) of clade A (p= 0.004) and Israeli sequences (from 2018 solely) of sub-clade IL-2018. The average survival rates of clade A and sub-clade IL-2018 were 58.1% (SD=21.5) and 31.2% (SD=25.6), respectively. This is one of only few field studies which show direct association of TiLV with mortality events in tilapia farms. The decrease in survival rate in the newly evolved clade might raise concern regarding virus evolution towards increased virulence, which should be further explored.

Valorization of Bokashi leachate as feed additive in tilapia farming

The Bokashi leachate (BL) is a by-product from the anaerobic digestion of food waste, following the Bokashi composting method. Bokashi leachate is acidic and it contains effective microorganisms hence it has potential to be a functional feed additive to the plant proteins based diets for fish farming. This study evaluated the growth performance and feed utilization of the red tilapia (Oreochromis sp.) fingerlings fed with the BL supplemented soybean meal (SBM) based diets. After an 8-week feeding trial, fish fed with the 5% BL supplemented SBM diet attained the highest weight gain. This result was significantly higher (p < 0.05) than those fed with the 0% BL supplemented SBM diet, and comparable (p > 0.05) to those fed with the control full fish meal (FM) diet. Generally, dietary inclusion of BL enhanced the fish feed intake on the SBM diet but it did not show clear sign of improvement in their feed utilization. In addition, no significant difference was found across the hepatosomatic index and viscerosomatic index from all dietary treatments. These outcomes concluded that dietary inclusion of BL can enhance the feed intake and growth performance of the red tilapia fingerlings fed with the SBM based diet without compromising their health, and the optimum BL inclusion level was 5%. Nevertheless, further study on the properties and substances content of the BL produced from different types and ratios of food waste is strongly recommended. In this study, BL was also discovered to be capable of reducing the crude fiber content in the SBM diets. Such observation deserves a further exploitation on the application of BL to manipulate the crude fiber content in the plant proteins based diets in fish farming.

Nitrogen and phosphorus dynamics in Nile tilapia farming in excavated rearing ponds

The purpose of this study was to determine the total nitrogen (TN) and total phosphorus (TP) balance during intensive tilapia farming in excavated ponds. To quantify TN and TP released into the environment, the supply water, effluents at the harvest time, fish composition, feed, and sediment were analysed. The mass balance between the amount of nutrients that is inserted through the feed, which is transformed into biomass by the fish and is retained in the sediment was calculated based on dry matter. The nutrient load arriving from the supply water was calculated as a function of the concentration of TN and TP. The TN and TP dynamics during the harvesting process in three different pond sizes identified that, on average, 2.37% of TN and 2.05% of TP inserted into the system during rearing is eliminated with 10.64% TN and 37.01% TP are retained in the sediment. The TN and TP input into the system occurs through the water supply, young fish, and the feed, the latter being responsible for about 92.87% TN and 96.05% TP. The feed composition indicates that the P level of the food is above the nutritional recommendations for the species. The amount of TP accumulated in the sediments indicates that there is a need for good management practices for water quality during the rearing and sediment management period before the beginning of a new production cycle.

Evaluation of the effect of the supplementation of Agaricus brasiliensis mushroom in cytohematological, growth and stress parameters in Nile tilapias (Oreochromis iloticus)

Currently, in fish farming, Nile tilapia farming is one of the most widespread types worldwide and is present on all continents.

Probiotics Modulate Tilapia Resistance and Immune Response against Tilapia Lake Virus Infection.

Tilapia lake virus (TiLV) causes an emerging viral disease associated with high mortality and economic damage in tilapia farming around the world. The use of probiotics in aquaculture has been suggested as an alternative to antibiotics and drugs to reduce the negative impact of bacterial and viral infections. In this study, we investigate the effect of probiotic Bacillus spp. supplementation on mortality, viral load, and expression of immune-related genes in red hybrid tilapia (Oreochromis spp.) upon TiLV infection. Fish were divided into three groups, and fed with: control diet, 0.5% probiotics-supplemented diet, and 1% probiotics-supplemented diet. After 21 days of experimental feeding, the three groups were infected with TiLV and monitored for mortality and growth performances, while organs were sampled at different time points to measure viral load and the transcription modulation of immune response markers. No significant difference was found among the groups in terms of weight gain (WG), average daily gain (ADG), feed efficiency (FE), or feed conversion ratio (FCR). A lower cumulative mortality was retrieved from fish fed 0.5% and 1% probiotics (25% and 24%, respectively), compared to the control group (32%). Moreover, fish fed with 1% probiotic diet had a significantly lower viral load, than those fed with 0.5% probiotic and control diet at 5, 6, 9, and 12 days post infection-challenge (dpc). The expression patterns of immune-related genes, including il-8 (also known as CXCL8), ifn-γ, irf-3, mx, rsad-2 (also known as VIPERIN) showed significant upregulation upon probiotic treatment during the peak of TiLV pathogenesis (between 9 and 12 dpc) and during most of the study period in fish fed with 1% probiotics-supplemented diet. Taken together, these findings indicate that dietary supplementation using Bacillus spp. probiotics may have beneficial effects to strengthen tilapia immunity and resistance against TiLV infections. Therefore, probiotic treatments may be preventively administered to reduce losses caused by this emerging viral infection in tilapia aquaculture.

Large-Scale Green Liver System for Sustainable Purification of Aquacultural Wastewater: Construction and Case Study in a Semiarid Area of Brazil (Itacuruba, Pernambuco) Using the Naturally Occurring Cyanotoxin Microcystin as Efficiency Indicator.

The aquaculture industry in Brazil has grown immensely resulting in the production of inefficiently discarded wastewater, which causes adverse effects on the aquatic ecosystem. The efficient treatment of aquaculture wastewater is vital in reaching a sustainable and ecological way of fish farming. Bioremediation in the form of the Green Liver System employing macrophytes was considered as wastewater treatment for a tilapia farm, COOPVALE, in Itacuruba, Brazil, based on previously demonstrated success. A large-scale system was constructed, and the macrophytes Azolla caroliniana, Egeria densa, Myriophyllum aquaticum, and Eichhornia crassipes were selected for phytoremediation. As cyanobacterial blooms persisted in the eutrophic wastewater, two microcystin congeners (MC-LR and -RR) were used as indicator contaminants for system efficiency and monitored by liquid-chromatography–tandem-mass-spectrometry. Two trial studies were conducted to decide on the final macrophyte selection and layout of the Green Liver System. In the first trial, 58% MC-LR and 66% MC-RR were removed and up to 32% MC-LR and 100% MC-RR were removed in the second trial. Additional risks that were overcome included animals grazing on the macrophytes and tilapia were spilling over from the hatchery. The implementation of the Green Liver System significantly contributed to the bioremediation of contaminants from the fish farm.