Search Results (53)

This study assessed the viable and culturable microbial diversity that remained on equipment surfaces after hygiene procedures in Brazilian poultry and fish slaughterhouses. Food-contact surface samples were collected using sterile swabs in poultry (n = 50) and fish (Oreochromis niloticus, n = 50) slaughterhouses. The swab samples were used to prepare culture plates to recover viable and culturable cells. The grown plates were washed, and the total DNA of the cell suspension was extracted with a commercial kit. Sequencing of the total DNA extracted from cultures was targeted at the V3 and V4 regions of the 16S rRNA. DNA reads were analyzed by QIIME2 software, with results expressed in relative frequency (%RF). Alpha and beta diversity indexes were analyzed considering the spots of sample collection, type of industry, surfaces (smooth or modular), and materials (polypropylene, stainless steel, or polyurethane). The results showed that in the poultry slaughterhouse, the most abundant genera were Acinetobacter (27.4%), Staphylococcus (7.7%), and Pseudomonas (5.3%), while for the fish slaughterhouse, there was a higher abundance of Staphylococcus (27.7%), Acinetobacter (17.2%), and Bacillus (12.5%). Surface characteristics influenced the microbial diversity, with Acinetobacter spp. dominating modular surfaces and Staphylococcus spp. prevailing on smooth surfaces. The results obtained indicate there is an important resident microbiota that persists even after hygiene processes, and surface-specific cleaning strategies should be developed. Full article

Growth traits are the most important economic traits in red tilapia (Oreochromis spp.) production, and are the main targets for its genetic improvement. Increasing salinity levels in the environment are affecting the growth, development, and molecular processes of aquatic animals. Red tilapia tolerates saline water to some degree. However, few credible genetic markers or potential genes are available for choosing fast-growth traits in salt-tolerant red tilapia. This work used genome-wide association study (GWAS) and RNA-sequencing (RNA-seq) to discover genes related to four growth traits in red tilapia cultured in saline water. Through genotyping, it was determined that 22 chromosomes have 12,776,921 high-quality single-nucleotide polymorphisms (SNPs). One significant SNP and eight suggestive SNPs were obtained, explaining 0.0019% to 0.3873% of phenotypic variance. A significant SNP peak associated with red tilapia growth traits was located on chr7 (chr7-47464467), and plxnb2 was identified as the candidate gene in this region. A total of 501 differentially expressed genes (DEGs) were found in the muscle of fast-growing individuals compared to those of slow-growing ones, according to a transcriptome analysis. Combining the findings of the GWAS and RNA-seq analysis, 11 candidate genes were identified, namely galnt9, esrrg, map7, mtfr2, kcnj8, fhit, dnm1, cald1, plxnb2, nuak1, and bpgm. These genes were involved in ‘other types of O-glycan biosynthesis’, ‘glycine, serine and threonine metabolism’, ‘glycolysis/gluconeogenesis’, ‘mucin-type O-glycan biosynthesis’ and ‘purine metabolism signaling’ pathways. We have developed molecular markers to genetically breed red tilapia that grow quickly in salty water. Our study lays the foundation for the future marker-assisted selection of growth traits in salt-tolerant red tilapia. Full article

Overexploitation has led to a rise in pathogenic bacteria within aquaculture, increasing reliance on antibiotics, and developing microorganism resistance. This situation underscores the need to explore alternatives with a reduced ecological impact. Metabolites derived from essential oils have demonstrated antimicrobial properties that can inhibit or diminish the activity of various microorganisms. In this study, the antimicrobial efficacy of cinnamon (Cinnamomum zeylanicum), tea tree (Melaleuca alternifolia), and thyme (Thymus vulgaris) essential oils against pathogenic bacteria (Aeromonas, Pseudomonas, Shewanella, Comamonas, Vibrio, Acinetobacter, and Empedobacter) isolated from tilapia (Oreochromis spp.) brooded in Hidalgo State, Mexico, were investigated. Diffusion tests were conducted using discs infused with 12 different antibiotics and discs infused with essential oils at concentrations of 15, 10, and 5 μL each. Minimal inhibitory concentration tests were performed using a 96-well microplate format. All bacterial strains exhibited multi-resistance to various antibiotics; however, thyme and cinnamon effectively inhibited the tested bacteria at the lowest concentrations, while tea tree oil was the least effective. The findings suggest the potential incorporation of thyme and cinnamon as an alternative prevention to decrease the use of antibiotic treatment. Full article

The increase in the human population has created pressure, due to the high consumption of natural resources, to meet basic needs. Poor waste management resulting from human activities has caused plastics to become pollutants that are present around the planet, including aquatic environments. The degradation of plastics through physicochemical processes has resulted in the presence of microplastics (particles < 5 mm), which have been found in species for human consumption and economic importance, including tilapia. In the last decade, research has shown the presence of microplastics in tilapia collected from different water bodies and aquaculture ponds, as well as in fish markets. In addition to this, there are studies that demonstrate that exposure to microplastics can have negative effects on the health of tilapia. The aim of this review is to compile and analyze the available information on microplastic contamination in Oreochromis spp., as well as in their environment, due to their importance as a species for human consumption. Full article

Tilapia (Oreochromis spp.) is a globally important farmed fish. Analyses of genetic variation across different types of tilapia are essential for the development of superior breeding populations. We investigated the genetic structures of breeding populations of blue tilapia (Oreochromis aureus) (OA), Nile tilapia (Oreochromis niloticus) (ON), and red tilapia (Oreochromis spp.) (OS) by whole-genome resequencing. The results showed that the OS population had maintained high genetic diversity but significant genetic differentiation from the OA population. Principal component analysis, phylogenetic analysis, and genetic clustering analysis revealed a clear pattern of genetic differentiation among the three populations. The genetic structure of the ON population differed from that of the OA population but was similar to that of the OS population. Population kinship analysis revealed a close relationship between the ON and OS populations. Selective scanning analyses of three comparison groups (OA vs. ON, OA vs. OS, and ON vs. OS) revealed population-selected regions related to metabolism, endocrine, and immune systems, harboring key genes (qrsl1, pde4d, hras, ikbkb, prkag1, prkaa2, prkacb, irs2, and eif4e2). These key genes were related to growth, reproduction, and disease resistance, indicating that breeding programs have selected for these traits. Due to the lack of stable morphological characteristics of juvenile fish and the changes in external environmental conditions that lead to changes in individual morphological characteristics, SNP fingerprints were successfully constructed for the identification of the three populations based on the differences in SNPs. Based on the five core SNP markers, two combinations of SNP markers were developed to accurately identify the three populations of tilapia at the genomic level. These results provide new information about tilapia genetic resources and reference data for identification and breeding purposes. Full article

Red tilapia is highly valued as a premium variety in Asia due to its vibrant red skin coloration. However, during aquaculture production, irregular black pigmentation (melanotic spots) frequently appears on the skin of some individuals, significantly reducing their economic value. Although epigenetic regulation is suspected to play a role, its involvement remains poorly understood. To uncover the molecular mechanisms underlying black spot formation, we employed Cleavage Under Targets and Tagmentation (CUT&Tag) to compare four key histone modifications (H3K4me3, H3K4me1, H3K27me3, and H3K27ac) between red and black pigmented skin regions. Integrated with transcriptomic analysis, our data indicated that red skin regions exhibited high expression of genes suppressing melanin synthesis, whereas melanotic spots likely resulted from localized derepression, allowing upregulation of melanin biosynthetic genes. Furthermore, by combining epigenomic chromatin state analysis and transcriptome data, we identified critical genes consistently active in melanotic spots and their corresponding potential cis-regulatory elements. Motif analysis of transcription factor binding sites upstream of these regulatory elements revealed that Ehf, Klf9, and Egr1 might facilitate melanin production in black regions, while Prdm1 and Sp5 could inhibit melanogenesis in red regions by repressing the Wnt signaling pathway. These findings provide valuable epigenetic insights into the mechanisms driving melanotic spot formation in red tilapia. Full article

Integrated aquaculture–agriculture systems (IAASs) offer a sustainable approach to mitigating soil salinity by utilizing aquaculture effluents for irrigation. This study evaluates the growth performance of Nile tilapia (Oreochromis niloticus) and red tilapia (Oreochromis spp.) under varying salinity conditions and investigates their effluents on intercropped wheat and sugar beet. A field experiment was conducted using a randomized block design with seven treatments: control (chemical fertilizers dissolved in freshwater) and brackish water effluents from Nile tilapia and red tilapia at salinities of 5 ppt and 10 ppt as monocultures or mixed polycultures. Fish growth parameters were assessed, while wheat and sugar beet morphological and yield traits were monitored. Statistical analyses, including correlation and principal component analysis, were performed. Red tilapia outperformed Nile tilapia at 10 ppt salinity, achieving the highest final weight (174.52 ± 0.01 g/fish) and weight gain (165.78 ± 0.01 g/fish), while the mixed polyculture at 10 ppt exhibited optimal feed conversion (FCR: 1.32 ± 0.01). Wheat growth and yield traits (plant height, stalk diameter, and panicle weight) declined significantly under salinity stress, with 10 ppt treatments reducing plant height by ~57% compared to the control. Conversely, sugar beet demonstrated resilience, with total soluble solids (TSS) increasing by 20–30% under salinity. The mixed effluent partially mitigated salinity effects on wheat at 5 ppt but not at 10 ppt. This study highlights the potential of IAAS in saline environments, demonstrating red tilapia’s adaptability and sugar beet’s resilience to salinity stress. In contrast, wheat suffered significant reductions in growth and yield. Full article

This study looked at how vacuum microwave drying (VMD) affects the quality of tilapia fillets (Oreochromis spp.). It focused on the impact of fillet thickness, microwave power, and vacuum pressure on key quality parameters, such as water activity (Aw), texture, rehydration rate, and whiteness. A series of experiments were conducted with varying fillet thickness (3–7 mm), microwave power (132–396 W), and vacuum pressure (0.03–0.07 MPa) using a Box-Behnken design to optimize drying conditions. The findings revealed that fillets with a thickness of 3 mm had the lowest Aw and the highest hardness, while 7 mm thick fillets had the best rehydration rate, elasticity, and whiteness. Additionally, increasing microwave power caused a gradual decrease in Aw and whiteness, while elasticity, hardness, and the rehydration rate initially increased and then decreased. As vacuum pressure increased, Aw decreased, and both whiteness and elasticity improved. The optimal drying conditions for tilapia fillets were identified as 7 mm thickness, 330 W microwave power, and 0.06 MPa vacuum pressure. Under these conditions, the dried fillets achieved a comprehensive quality score of 93.94. The regression model developed for optimization showed strong predictive performance, with a minimal deviation of only 1.45% from the experimental results, indicating its reliability for predicting drying effects. Full article

Due to the recent taxonomic reclassification of the species Flavobacterium columnare into four new species—Flavobacterium columnare, Flavobacterium davisii, Flavobacterium covae, and Flavobacterium oreochromis—it is necessary to re-evaluate isolates of previous outbreaks to better understand the epidemiology related to this bacterial group. Therefore, the aim of this study was to determine the taxonomic profile of Brazilian isolates of Flavobacterium spp. associated with columnaris disease using available diagnostic methods. Fifty isolates from different outbreaks (17 clinical cases) occurring in five different Brazilian states previously identified as F. columnare were selected and identified by multiplex PCR and MALDI-ToF methods. In addition, at least one isolate from each clinical case was analyzed by 16S rRNA gene sequencing. After inclusion of the MSPs (main spectra profiles), the isolates were identifiable, and when compared with the multiplex PCR results, they showed almost perfect agreement (94.2% Kappa = 0.85). Only F. davisii, F. covae, and F. oreochromis were found among the Brazilian isolates, with these species causing disease in neotropical fish hosts not previously reported (e.g., Siluriformes, Serrasalmidae, and Bryconidae), while F. columnare was not detected. This study provides evidence of Flavobacterium species associated with columnaris disease circulating in various aquaculture facilities across different regions of Brazil. This information is crucial for developing control programs and advancing epidemiologic studies on columnaris disease in Brazilian aquaculture. Full article

Cold stress during overwintering is considered a bottleneck problem limiting the development of the red tilapia (Oreochromis spp.) industry, and the regulation mechanism is currently not well understood. In this study, the fish (initial weight: 72.71 ± 1.32 g) were divided into the cold stress group (cold) and the control (normal) group. In the control group, the water temperature was maintained at 20 °C, which is basically consistent with the overwintering water temperature in greenhouses of local areas. In the cold group, the water temperature decreased from 20 °C to 8 °C by 2 °C per day during the experiment. At the end of the experiment, the levels of fish serum urea nitrogen, glucose, norepinephrine, alkaline phosphatase, total bilirubin, and total cholesterol in the cold group changed significantly compared with that in the control group (P < 0.05). Then transcriptome sequencing and LC–MS metabolome of brain tissue were further employed to obtain the mRNA and metabolite datasets. We found that the FoxO signaling pathway and ABC transporters played an important role by transcriptome–metabolome association analysis. In the FoxO signaling pathway, the differentially expressed genes were related to cell cycle regulation, apoptosis and immune-regulation, and oxidative stress resistance and DNA repair. In the ABC transporters pathway, the ATP-binding cassette (ABC) subfamily abca, abcb, and abcc gene expression levels, and the deoxycytidine, L-lysine, L-glutamic acid, L-threonine, ornithine, and uridine metabolite contents changed. Our results suggested that the cold stress may promote apoptosis through regulation of the FoxO signaling pathway. The ABC transporters may respond to cold stress by regulating amino acid metabolism. The results provided a comprehensive understanding of fish cold stress during overwintering, which will facilitate the breeding of new cold-resistant varieties of red tilapia in the future. Full article

Coinfections by multiple pathogens, including viruses and bacteria, have severely impacted tilapia aquaculture globally. This study evaluated the impacts of dietary supplementation on red hybrid tilapia (Oreochromis spp.) coinfected with Tilapia lake virus (TiLV) and Aeromonas hydrophila. Fish were divided into three groups: a control group on a normal diet, and two experimental groups received diets supplemented with strategy A, an organic acid blend combined with a lyso-phospholipid-based digestive enhancer, and strategy B, an organic acid blend combined with natural immunostimulants and nutrients. Following exposure to both pathogens, the fish supplemented with strategies A and B showed lower cumulative mortality rates of 50.0% and 41.7%, respectively, compared to 76.3% in the control group. Notably, fish fed with strategy B-supplemented diet displayed a stronger immune response, with a lower expression of il-8, mx, and rsad2, and showed less pathological changes in the liver, spleen, and intestines, suggesting enhanced resistance to coinfection. In contrast, fish receiving strategy A did not exhibit significant changes in the immune-related gene expression or pathogen load, but demonstrate less pathological alterations, indicating intestinal protection. These findings highlight the potential of feed additives, particularly strategy B, to reduce the impact of virus-bacterial coinfections and improve outcomes in tilapia farming. Full article

Tilapia lake virus (TiLV) presents a substantial threat to global tilapia production. Despite the development of numerous cell lines for TiLV isolation and propagation, none have been specifically derived from red hybrid tilapia (Oreochromis spp.). In this study, we successfully established a new cell line, RHTiB, from the red hybrid tilapia brain. RHTiB cells were cultured for 1.5 years through over 50 passages and demonstrated optimal growth at 25 °C in Leibovitz-15 medium supplemented with 10% fetal bovine serum at pH 7.4. Morphologically, RHTiB cells displayed a fibroblast-like appearance, and cytochrome oxidase I gene sequencing confirmed their origin from Oreochromis spp. Mycoplasma contamination testing yielded negative results. The revival rate of the cells post-cryopreservation was observed to be between 75 and 80% after 30 days. Chromosomal analysis at the 25th passage revealed a diploid count of 22 pairs (2n = 44). While no visible cytopathic effects were observed, both immunofluorescence microscopy and RT-qPCR analysis demonstrated successful TiLV propagation in the RHTiB cell line, with a maximum TiLV concentration of 10^{7.82 ± 0.22} viral copies/400 ng cDNA after 9 days of incubation. The establishment of this species-specific cell line represents a valuable advancement in the diagnostic and isolation tools for viral diseases potentially impacting red hybrid tilapia. Full article

Though different types of commercial probiotics are supplemented in biofloc technology (BFT), very little information is available on their effects on the farmed fish. Therefore, this study focused on evaluating the effects of three most commonly used commercial probiotics on the growth performance, intestinal histomorphology, and intestinal microbiota of Nile tilapia (Oreochromis niloticus) reared in BFT. Tilapia fry, with an average weight of 3.02 ± 0.50 g, were stocked at a density of 60 fry/0.2 m³, and cultured for 90 days. Three commercial probiotics were administered, with three replications for each: a single-genus multi-species probiotic (Bacillus spp.) (T1), a multi-genus multi-species probiotic (Bacillus sp., Lactobacillus sp., Nitrosomonas sp., Nitrobacter sp.) (T2), and a multi-species probiotic (Bacillus spp.) combined with enzymes including amylase, protease, cellulase, and xylanase (T3). The results showed significant variations in growth and feed utilization, with T3 outperforming other treatments in terms of weight gain, liver weight, and intestine weight. Adding Bacillus spp. with enzymes (T3) to water significantly increased the histomorphological parameters (villi length, villi depth, crypt depth, muscle thickness, intestinal thickness) as well as microbes (total viable count and total lactic acid bacteria) of intestine of fish compared to T1 and T2, leading to improved digestion and absorption responses. It is concluded that the supplementation of commercial probiotics has potential benefits on farmed fish species in BFT. Full article

The homeostasis of the intestinal microbiota of fish is beneficial to fish health, while food can affect the intestinal microbiota. Tilapia (Oreochromis spp.) has great economic value and is a good model to use in studying the digestion and absorption of nutrients. Furthermore, at present, due to a high demand and high price of high-quality feed raw materials, the nutritional composition of aquafeeds has been changing dynamically. There has yet to be a comprehensive review of research conducted on the influences of dietary macronutrients (proteins, lipids, and carbohydrates) on the tilapia intestinal microbiota. Therefore, this review focuses on the effects of dietary macronutrients on the gut microbiota of tilapia. Interestingly, we found that the best growth performance might not represent the best composition or functions of the gut microbiota. Overall, the unscientific addition of macronutrients to feed is harmful to the intestinal microbiota. Therefore, both growth performance and gut microbiota should be considered when evaluating certain macronutrients. It is our hope that this review will aid in regulating the intestinal microbiota of fish through nutritional means, thereby promoting tilapia farming. Full article

The objective of this systematic review was to identify and classify, from the available literature, non-conventional feed ingredients from terrestrial plants, animals, algae, and fungi which have been evaluated for their potential use for tilapia (Oreochromis spp.) production. For this purpose, 795 papers published in the Scopus and Web of Science databases between 2011 and 2021 were analyzed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Data on the growth rate (GR) and effects on weight gain (WG), specific growth rate (SGR) and feed conversion ratio (FCR); digestibility; fatty acid profile (FAP) of the fish carcass; and the survival rate (SR) were compiled in databases and summary tables. The results were refined according to different criteria, obtaining 144 documents that were pertinent for an in-depth analysis. From those, we found that 50.7% evaluated terrestrial plants, 22.2% animals, 13.9% algae, 9% fungi, and the remaining, combinations of some of the above categories. From the summarized results we concluded that most of the non-conventional sources analyzed have a positive potential impact as alternatives for producing tilapia. Survival was the most evaluated parameter, while digestibility was the least evaluated parameter. Full article