Intestine Of Tilapia Research Articles

Heat inactive Bacillus subtilis var. natto regulate Nile tilapia (Oreochromis niloticus) intestine microbiota and metabolites involved in the intestine phagosome response

In this study, we evaluated the intestinal microbiota, intestinal and fecal metabolites production and the intestinal RNA-seq analysis of the Nile tilapia intestine after feeding with 105and 107 of the inactive Bacillus subtilis var. natto.First, we assessed the influence of heat inactive Bacillus subtilis var. natto on the growth performance, biochemical blood analysis, and evaluated the liver/body, spleen/body and intestine/body ratio. This evidence was known feeding with inactive Bacillus subtilis var. natto was able to improve the growth performance after 4 weeks, but not to affect the inflammatory biochemical blood parametres total protein (T-pro), albumin (Alb), Alb/T-pro ratio, creatine-phospho-kinase (CPK) and lactate dehydrogenase (LDH). Further, in the intestine microbiota, the Lactobacillaceae, Firmicutes, Chromatiales, and Rhodobacteria, was significantly higher than the control and the Firmicutes/Bacteroidetes ratio (F/B), which was indicated with a significantly increased. The intestine tissue metabolites OPLS-DA analysis indicated that the prominent bioactive metabolites changed. The peonidin-3-glucoside, l-Tyrosine, 1-Deoxy-1-(N6-lysino)-d-fructose was significantly increased. The feces metabolite OPLS-DA analysis indicated that the palmitelaidic acid, 5-KETE, tangeritin was significantly increased. In the transcriptome, the Gene Ontology (GO) analysis was found to enhance the intestine intestinal immune network. Combine of these evidence, feeding of the heat inactive Bacillus subtilis var. natto exactly improved the O. niloticus growth performance and regulation of the microbiota to promote the metabolites. In the transcriptome analysis, it was found to involve in the intestine immune phagosome response.Summarized of this study, the heat inactive Bacillus subtilis var. natto was reported to affect Nile tilapia intestine microbiota, and could positively regulate the intestine and fecal metabolites production to improve the intestine immune network.

The Dietary Mixture of Betaine, Lactic Acid Bacteria, and Exogenous Digestive Enzymes Enhanced the Growth Performance, Intestinal Health, and Immunity of Nile Tilapia (Oreochromis niloticus) Grown in Outdoor Concrete Tanks

Abstract It has been illustrated that using mixtures of feed additives is more efficient than using individual additives in aquaculture. Hence, this study aimed to study a dietary mixture of betaine, lactic acid bacteria, and exogenous digestive enzymes (BLE) on the growth performance, digestion capacity, intestinal health, and blood indices of Nile tilapia reared outdoors in concrete tanks. Five diets were prepared where the basal diets were mixed with BLE at 0, 0.25, 0.5, 0.75, and 1%. After 90 days, the growth performance of Nile tilapia fed BLE was markedly enhanced in fish fed 0.25 and 0.5% of BLE, while the feed conversion ratio (FCR) was reduced (P<0.05). The lipase activity was significantly higher in tilapia fed BLE at 0.25, 0.5, and 0.75% than 0 and 1%. The amylase activity was meaningfully increased by 0.5% of BLE than 0, 0.25, 0.75, and 1%. The protease activity was significantly higher in tilapia fed BLE at 0.25 and 0.5 than 0, 0.75, and 1% (P<0.05). The intestine of fish fed on BLE showed an increase in intestinal villi density. The villi length, width, and the number of goblet cells were markedly higher in the anterior, middle, and posterior segments of the intestines of tilapia fed BLE than in the control group (P<0.05). Further, fish fed BLE had higher intestinal morphometry indices and count of goblet cells than the control. Significantly fish fed 0.25, and 0.5% of BLE had higher hemoglobulin, and hematocrit levels than fish fed 0, 0.75, and 1%. While, fish fed 0.5% had higher red blood cells than fish fed the remaining BLE levels (P<0.05). On the other hand, no marked effects for BLE supplementation were seen on the alanine aminotransferase (ALT), aspartate aminotransferase (AST), total protein, albumin, globulin, creatinine, uric acid, and urea. The regression analysis showed that the maximum dose of BLE supplementation to achieve the highest final weight and the lowest FCR is 0.46% and 0.42%, respectively.

Significant alterations of intestinal symbiotic microbiota induced by intraperitoneal vaccination mediate changes in intestinal metabolism of NEW Genetically Improved Farmed Tilapia (NEW GIFT, Oreochromis niloticus)

BackgroundAfter millions of years of coevolution, symbiotic microbiota has become an integral part of the host and plays an important role in host immunity, metabolism, and health. Vaccination, as an effective means of preventing infectious diseases, has been playing a vital role in the prevention and control of human and animal diseases for decades. However, so far, minimal is known about the effect of vaccination on fish symbiotic microbiota, especially mucosal microbiota, and its correlation with intestinal metabolism remains unclear.MethodsHere we reported the effect of an inactivated bivalent Aeromonas hydrophila/Aeromonas veronii vaccine on the symbiotic microbiota and its correlation with the intestinal metabolism of farmed adult Nile tilapia (Oreochromis niloticus) by 16S rRNA gene high-throughput sequencing and gas chromatography-mass spectrometry metabolomics.ResultsResults showed that vaccination significantly changed the structure, composition, and predictive function of intestinal mucosal microbiota but did not significantly affect the symbiotic microbiota of other sites including gill mucosae, stomach contents, and stomach mucosae. Moreover, vaccination significantly reduced the relative abundance values of potential opportunistic pathogens such as Aeromonas, Escherichia–Shigella, and Acinetobacter in intestinal mucosae. Combined with the enhancement of immune function after vaccination, inactivated bivalent Aeromonas vaccination had a protective effect against the intestinal pathogen infection of tilapia. In addition, the metabolite differential analysis showed that vaccination significantly increased the concentrations of carbohydrate-related metabolites such as lactic acid, succinic acid, and gluconic acid but significantly decreased the concentrations of multiple lipid-related metabolites in tilapia intestines. Vaccination affected the intestinal metabolism of tilapia, which was further verified by the predictive function of intestinal microbiota. Furthermore, the correlation analyses showed that most of the intestinal differential microorganisms were significantly correlated with intestinal differential metabolites after vaccination, confirming that the effect of vaccination on intestinal metabolism was closely related to the intestinal microbiota.ConclusionsIn conclusion, this paper revealed the microbial and metabolic responses induced by inactivated vaccination, suggesting that intestinal microbiota might mediate the effect of vaccination on the intestinal metabolism of tilapia. It expanded the novel understanding of vaccine protective mechanisms from microbial and metabolic perspectives, providing important implications for the potential influence of vaccination on human intestinal microbiota and metabolism.-tufGxbkxhm-UiFTxxYHNiVideo

The Role of Prebiotics for Diversity of Intestinal Microorganisms of Tilapia (Orechromis niloticus)

Prebiotics are undigested food ingredients that can be utilized by intestinal microorganisms. The provision of prebiotics will improve growth performance, inhibit the growth of pathogens, and increase fish immunity. Several previous aquaculture studies have used single prebiotics as prebiotics, such as FOS, GOS, and inulin. We need a material that is multi prebiotics which is expected to give better results. Honey is a material that includes multi prebiotics. The purpose of this study was to evaluate the administration of prebiotic honey with different doses (0%, 05%, and 1% doses) through feeding on the diversity of microbiota in the digestive tract of tilapia (Oreochromis niloticus). The method used in this study was to take samples of tilapia intestines, then analyzed them using Next Generation Sequencing (NGS). The results showed that the most unique OTU were in the treatment of prebiotic honey with a dose of 1%. The treatment of prebiotic honey in the feed gave a higher OTU compared to the control. This is because the oligosaccharide content of honey can be utilized by the gut microbiota. The high unique OTUs in the treatment of adding honey, both 0.5% and 1%, presumably because these unique OTUs can grow well in that environment so that there is an equilibrium between species that together can utilize nutrients from honey oligosaccharides. so that all components of the microbiota can grow optimally. Prebiotic honey given to tilapia also triggers the emergence of the genus Lactobacillus, Cetobacterium, and Clostridium sensu stricto which are probiotic bacteria in the fisheries sector.

Attenuated Streptococcus agalactiae WC1535 ∆Sia perturbs the gut microbiota of Oreochromis niloticus, massively colonizes the intestine, and induces intestinal mucosal immunity after intraperitoneal inoculation.

We previously developed and assessed the effectiveness of the attenuated Streptococcus agalactiae (Group B Streptococcus, GBS) strain WC1535 ∆Sia (with neuA-D gene cluster deletion) vaccine in tilapia (Oreochromis niloticus). In this study, we characterized the bacterial communities of the tilapia intestines by 16S rRNA high-throughput sequencing and assessed the serum antibody response, expression of immune-related genes, and histological changes following formalin-killed GBS vaccine (FKV) and the live attenuated vaccine ∆Sia (LAV). Results showed that FKV and LAV induced robust systemic and intestinal mucosal immune responses in tilapia without causing obvious pathological changes in the hindgut, spleen, and head kidney but exerted different effects on intestinal bacterial communities. The richness or diversity of the intestinal bacterial community of FKV tilapia showed no significant changes compared with that of the control fish (p > 0.05) at either day 21 post-initial vaccination (21 dpiv) or day 35 (day 14 after the second immunization) (35 dpiv). The community composition of FKV tilapia and controls was significantly similar, although the relative abundance of some genera was significantly altered. Relative to control fish, the gut ecosystem of LAV tilapia was significantly disturbed with a substantial increase in community diversity at 21 dpiv (p < 0.05) and a significant decrease at 35 dpiv in fish with high serum antibody response (ΔSia35H) (p < 0.05). However, there was no significant difference between ΔSia35H and ΔSia35L (low serum antibody response) fish (p > 0.05). Moreover, the community composition of LAV tilapia at 21 dpiv or 35 dpiv was considerably different from that of the controls. Particularly, GBS ∆Sia was found to be abundant in the intestine at 21 and 35 dpiv. This result suggested that the parenteral administration of the LAV (∆Sia) may also have the effect of oral vaccination in addition to the immune effect of injection vaccination. In addition, a significant correlation was found between the expression of immune-related genes and certain bacterial species in the intestinal mucosal flora. Our findings will contribute to a better understanding of the effects of inactivated and attenuated vaccines on gut microbiota and their relationship with the immune response.

Vibrio load and percentage composition of sucrose‐fermenting vibrios in Nile tilapia ( Oreochromis niloticus ) cultured in brackish water earthen ponds and biocontrol potential of recycled tilapia‐conditioned greenwater against population growth of V. parahaemolyticus and non‐sucrose‐fermenting vibrios in the grow‐out culture of white leg shrimp ( Litopenaeus vannamei )

Vibrio are known opportunistic pathogens of pond-cultured fish and shrimp. This study determined the presumptive Vibrio count (PVC) and percentage composition of “beneficial” sucrose-fermenting vibrios (SFVs) and “pathogenic” non-SFVs in the water, sediment, gills and intestines of healthy tilapia Oreochromis niloticus collected every 2 weeks from Days 30 to 120 post-stocking in brackish water earthen ponds. PVCs in water and sediment ranged from 102–104 CFU/ml/CFU/g while in tilapias' gills and intestines, PVCs ranged from 103–106 CFU/g and 102–106 CFU/g, respectively, with SFVs dominating in water, sediment, gills (≥50%), and intestines (≥80%) of tilapia. Because use of tilapia-conditioned green water (TCGW) for shrimp's grow-out culture has been reported effective against acute hepatopancreatic necrosis disease outbreaks caused by V. parahaemolyticus, PVC, SFVs/non-SFVs (%), and V. parahaemolyticus count (VPC) in the recycled TCGW and Litopenaeus vannamei's hepatopancreas were also examined from stocking until 105 days of culture (DOC) in earthen ponds. PVCs ranging from 102–103 CFU/ml and 103–104 CFU/g were noted in water and shrimp's hepatopancreas, respectively. While non-SFVs population in water varied, a downward trend typified by an abrupt 50% reduction was noted in hepatopancreas at DOC 42, and remained or further dropped until DOC 105. VPCs in water likewise varied (undetectable–102 CFU/ml) while in hepatopancreas, counts dropped to undetectable level from DOC 70 onwards. Current data illustrate that remarkable shift of SFVs' dominance in the water and concomitantly in shrimp's hepatopancreas, plays a pivotal role in regulating non-SFVs proliferation in shrimp's hepatopancreas via competitive exclusion.

Питание тиляпии мозамбикской (Oreochromis mossambicus) бактериально-водорослевыми матами в водоёме-охладителе Нововоронежской АЭС

The formation of stable periphyton communities is undesirable for all types of hydrotechnical systems, especially functioning watercooling systems. To combat the development of biological fouling in the cooling ponds of nuclear power plants bioreclamation species are widely used, which include Mozambican tilapia. It was unintentionally brought into the cooling reservoir of the Novovoronezh nuclear power plant; however, it formed a stable and numerous population there. The food base for the fish population in the cooling pond is depleted due to difficult (sometimes extreme) environmental conditions, which can lead to competition for food items. Under these conditions, tilapia switches to feeding on bacterial-algal mats, which develop abundantly in the warm-water part of the reservoir. In areas eaten by tilapia, the biomass of fouling is reduced by one and a half times and the content of mineral substances decreases. The study of the contents of the intestines of tilapia made it possible to confirm these observations, since representatives of the phytoperiphyton were found in the food bolus: cyanoprokaryotes, diatoms and green algae, for which even a taxonomic affiliation was established. The results of the research made it possible to clarify the mechanism o f integration of this southern species into the ichthyocenosis of the reservoir and its positive role in reducing biofouling.

A Bacillus cereus NY5 strain from tilapia intestine antagonizes pathogenic Streptococcus agalactiae growth and adhesion in vitro and in vivo

Bacillus cereus NY5 is a potential probiotic isolated from healthy tilapia (Oreochromis niloticus) gut. In this study, the antagonism of this bacterium against pathogenic Streptococcus agalactiae WC1535 from tilapia was evaluated in vitro and in vivo. Through antagonistic culture, artificial infection, histological micro- and ultramicroscopic detection, and gene expression monitoring, the ability of NY5 to inhibit the growth of WC1535, attenuate its ability to invade tilapia tissue, promote immune cell secretion, and affect host immune gene expression were studied. When NY5 and WC1535 were co-incubated in BHI (brain-heart infusion) or LB (Luria-Bertani) medium, NY5 effectively inhibited the growth of WC1535. Under immersion infection, NY5 attenuated the ability of WC1535 to adhere to the body surface of fish. In oral infection, NY5 effectively inhibited WC1535 from invading tilapia cells, increased the number of goblet cells in the midgut epidermis, and improved the fish survival rate. Moreover, NY5 increased the mitochondria in the midgut of S. agalactiae-infected tilapia. Under oral infection for 20 h, the relative expression levels of the immune-related genes GATA3, LgM, 1L-10, TCR-β, TNF, and TP3 were higher in tilapia treated with WC1535 than in tilapia treated with both NY5 and WC1535 (NY5-WC1535) and with NY5. The MHCII and TGF-β expression levels were higher in the NY5-WC1535 and NY5 treatments (p < 0.05), and the CD4 and MHCI expression levels were higher in WC1535 and NY5-WC1535 treatments (p < 0.05). These results indicate that B. cereus NY5 can effectively reduce tilapia mortality under S. agalactiae infection. The main antagonistic mechanism appears to be inhibiting the growth of S. agalactiae through nutrient deprivation or by secreting extracellular products and reducing its ability to invade and infect. Antagonism was also achieved by modulating specific and non-specific immunity in tilapia infected with S. agalactiae. The findings suggest that B. cereus NY5 may be a potential bacterial antagonist for controlling S. agalactiae infections in tilapia aquaculture.

Motile aeromonads recovered from tilapia (Oreochromis niloticus) cultured in earthen ponds in the Philippines: assessment of antibiotic susceptibility and multidrug resistance to selected antibiotics

A total of 177 motile Aeromonas spp., comprised of A. hydrophila (n=162) and A. sobria (n=15), isolated from the water, sediment, gills and intestines of tilapia collected from the grow-out culture earthen ponds in the Philippines were investigated for their antimicrobial susceptibility to 10 antibiotics commonly used in fish aquaculture. All motile Aeromonas spp. tested generally exhibited a very high percentage of resistance to amoxicillin (A. hydrophila: 95%; A. sobria: 100%), erythromycin (99%;100%), neomycin (83%;100%), and oxytetracycline (92%;100%), respectively. On the contrary, they showed substantial susceptibility to chloramphenicol, nitrofurantoin, doxycycline, enrofloxacin and norfloxacin. Results of the antimicrobial susceptibility testing demonstrated that 94.4% and 100% of A. hydrophila and A. sobria isolates tested were resistant to antibiotics belonging to at least 3 or more categories and therefore considered as multiple drug resistant strains. The multiple antibiotic resistance (MAR) indexing of A. hydrophila and A. sobria strains showed that they originated from high-risk sources.

Influences of the alcoholic extract of Artemisia annua on gastrointestinal microbiota and performance of Nile tilapia

There is growing interest in strategies for manipulating the gut microbiota of fish for beneficial communities to increase growth, improve lipid metabolism, stimulate the immune response, and improve the physiological state of the gut. We investigated the effects of diets supplemented with an alcoholic extract of Artemisia annua (ae-Aa) on gastrointestinal (GI) microbiota and intestinal morphology along with its effects on the growth performance of the Nile tilapia (Oreochromis niloticus). Juveniles were fed with ae-Aa supplementation (0.00, 0.10, 0.25, and 0.50% in the diets) for 30 days. The different ae-Aa supply levels affected bacterial interactions, resulting in a more complex network and increasing the proportion of positive correlations between bacterial groups. The different amounts of ae-Aa caused variations in specific bacterial abundance. The phyla Fusobacteriota and Bacteroidota were dominant in the intestinal microbiota in all experimental groups. The abundance of bacteria belonging to Fusobacteriaceae, Stenotrophomonas, and Clostridium correlated positively with protein efficiency, specific growth rate, weight gain, and final weight, while the opposite was observed for Acinetobacter. Diets supplemented with 0.25 and 0.5% of ae-Aa increased (p < 0.05) perimeter, height, and thickness of villi, crypt depth, villus:crypt ratio, and number of goblet cells in the intestine of Nile tilapia compared to control group. Nile tilapia supplemented with ae-Aa at all levels improved growth performance (weight gain, specific growth rate, and protein efficiency rate; p < 0.05) and feed conversion ratio (p < 0.05) compared to the control group. The weight gain was about 21% better in supplemented fish with ae-Aa than unsupplemented ones. The ae-Aa supplementation of Nile tilapia for 30 days modulated the GI microbiota communities providing variations in specific bacterial abundance, affecting the bacterial interactions, resulting in a more complex, stable, and connected network while changing their intestinal morphology and improving the performance of the fish.

Effect of polysaccharides derived from brown macroalgae Sargassum dentifolium on growth performance, serum biochemical, digestive histology and enzyme activity of hybrid red tilapia

The present trial conducted to examine the impact of dietary red seaweeds, Sargassum dentifolium polysaccharides supplementation on growth induces, hematological and histological indicators of the hybrid red tilapia Oreochromis mossambicus × Oreochromis niloticus fingerlings. A total of 240 hybrid red tilapia fingerlings with an average body weight of 7.50 ± 0.01 g were divided into four experimental treatments (three replicates each). Four identical isonitrogenous isoenergetic diets except the variation of polysaccharide (SP) levels were formulated. The basal experimental diet (control diet) had no seaweed polysaccharide added (SP0). Diets 2–4 (SP1; SP2 and SP3) was formulated to contained seaweed polysaccharide at levels of 10, 20, and 30 g/kg diet, respectively. Growth performance and feed utilization efficiency of hybrid Red tilapia were significantly (P ≤ 0.05) higher in all treatments receiving SP supplemented-diets than the control diet. The red blood cells (RBCs), hemoglobin (Hb) and hematocrit (Hct, %) values differed significantly (P ≤ 0.05) between the control and fish fed various SP supplemented diets. Considering the dietary SP supplementation, a clear higher trend values of RBC was observed with increasing dietary SP inclusion. Lipase activity recorded the highest values with the fish fed diet supplemented with SP at a level of 20 g/kg-1 associated with the lower significant values amylase activity compared to other treatments. Dietary SP supplementation had no effect on total plasma protein, albumin and globulin levels. Fish fed SP2 diet had an increase in GOT, triglycerides. Fish fed SP3 recorded the lowest value of total cholesterol and LDL when compared to other diets. No abnormal or histological changes were detected in sections of liver, stomach and intestine of red tilapia fed different dietary supplemented with SP levels. The findings of current trial revealed that hybrid Red tilapia fed diets containing red seaweeds, polysaccharides for 12 weeks had enhanced performance, feed conversion ratio and hematological indices.

Effects of Diet on the Gut Microbial Communities of Nile Tilapia (Oreochromis niloticus) Across Their Different Life Stages

Nile tilapia (Oreochromis niloticus) is one of the most important commercial freshwater fish in China, and dietary transition occurs in their different life stages. The gut microbiota is important to host health. The relationships among the diet, gut microbiota, and development of tilapia are not well known. In the present study, we attempted to understand how diet is associated with microbiota community dynamics during the development of tilapia. The first experiment was performed under standard laboratory feeding operation to determine the effect of diet transition on intestinal microbiota. In the second experiment, tilapia were fed with Artemia or plant-based dry (PBD) food from the fish started feeding to their late juvenile stage (90 days post-fertilization). The results in the first experiment showed that feeding habit transition in juvenile fish had a low effect on the microbiota of the tilapia intestine. In the second experiment, plant-based food negatively affected the survival rate and intestinal development of tilapia. The phylum Planctomycetes was dominant in juvenile fish fed PBD food. The phylum Fusobacteria was dominant in the juvenile fish fed Artemia. At the genus level, Gemmobacter, Pirellula, and Planctomyces, belonging to the phylum Planctomycetes, were significantly abundant in the guts of fish fed the PBD food diet. Cetobacterium of the phylum Fusobacteria was dominant in juvenile fish fed Artemia. Thus, we can conclude that diet types have a great effect on the microbiota of tilapia intestine in their early life stages. The intestinal microflora of tilapia was established in juvenile tilapia, approximately 2 months after hatching. Our results provide useful information for the experimental design of studies on the microbial community of the tilapia gut. We suggest that modulation of gut microbiota of tilapia could be performed in their early life.

Effects of Soluble and Insoluble Non-Starch Polysaccharides on Growth Performance, Digestive Enzyme Activity, Antioxidant Capacity, and Intestinal Flora of Juvenile Genetic of Improvement of Farmed Tilapia (Oreochromis niloticus)

This study aimed to evaluate the effects of soluble and insoluble non-starch polysaccharides (NSPs) on growth performance, digestive enzyme activity, antioxidant capacity, and intestinal flora of juvenile GIFT tilapia (Oreochromis niloticus). Four isonitrogenous and isolipidic experimental diets were formulated, including the FM diet (0% NSPs, FM), INSP diet (5.8% insoluble NSPs, INSP), SNSP diet (12.2% soluble NSPs, SNSP), and NSP diet (5.8% INSP and 12.2% SNSP, NSPs). Each diet was fed to triplicate groups of 40 fish (2.14 ± 0.04 g) per repetition for 10 weeks. Results showed that dietary supplementation with different types of NSPs significantly affected the digestive enzyme activity, antioxidant capacity, and intestinal flora of juvenile GIFT tilapia. Specifically, dietary supplementation with INSP significantly increased pepsin and intestinal lipase activity, while dietary supplementation with SNSP significantly decreased intestinal lipase activity and resulted in a significant decrease in plasma catalase, glutathione peroxidase, and total antioxidant capacity activity. Meanwhile, dietary supplementation with SNSP significantly increased the concentration of urea nitrogen and high-density lipoprotein cholesterol in plasma and alanine aminotransferase activity in plasma and hepatic. Moreover, LEfSe analysis showed that dietary supplementation with SNSP significantly increased the abundance of Bacteroidales, Bacteroidia, and Cellulosilyticum, while dietary supplementation with NSPs significantly decreased the abundance of Mycobacteriaceae, Mycobacterium_neoaurum, Corynebacteriales, and Mycobacterium. These results suggest that dietary INSP is an inert ingredient with limited effect, while dietary SNSP inhabited antioxidant capacity, induced liver damage, and altered the abundance of anaerobic/aerobic bacteria in the intestine of GIFT tilapia.

Tilapia can be a Beneficial n-3 LC-PUFA Source due to Its High Biosynthetic Capacity in the Liver and Intestine.

To assess whether farmed tilapia can be a beneficial n-3 long-chain polyunsaturated fatty acid (LC-PUFA) source for human health, four diets with linoleic acid (LA) to α-linolenic acid (ALA) ratios at 9, 6, 3, and 1 were prepared to feed juveniles for 10 weeks, and the LC-PUFA biosynthetic characteristics in the liver, intestine, and brain and the muscular quality were analyzed. It was shown that the n-3 LC-PUFA levels of the intestine and liver increased in a parallel pattern with the dietary ALA levels. Correspondingly, in the fish fed diet with high ALA levels, the mRNA levels of genes related to LC-PUFA biosynthesis including fads2, elovl5, and pparα in the intestine and elovl5 in the liver were increased, and the muscular n-3 LC-PUFA levels and textures were improved. The results demonstrated that tilapia intestine and liver possess high n-3 LC-PUFA biosynthetic capacity, which suggests that farmed tilapia can be a beneficial n-3 LC-PUFA source.

A Novel Bacteriocin Against Shigella flexneri From Lactiplantibacillus plantarum Isolated From Tilapia Intestine: Purification, Antibacterial Properties and Antibiofilm Activity.

Few bacteriocins with antibacterial activity against Shigella flexneri have been reported. Here, a novel bacteriocin (LFX01) produced by Lactiplantibacillus plantarum strain LF-8 from the intestine of tilapia was purified and extensively characterized. LFX01 possesses a molecular weight of 1049.56 Da and an amino acid sequence of I-T-G-G-P-A-V-V-H-Q-A. LFX01 significantly inhibited S. flexneri strain 14 (S. flexneri_14) growth. Moreover, it exhibited excellent stability under heat and acid-base stress, and presented sensitivity to a variety of proteases, such as proteinase K, pepsin, and trypsin. The minimum inhibitory concentration (MIC) of LFX01 against S. flexneri_14 was 12.65 μg/mL, which was smaller than that of most of the previously found bacteriocins. Furthermore, LFX01 significantly inhibited (p < 0.05) S. flexneri_14 cells and decreased their cell viability. In addition, LFX01 could significantly (p < 0.05) inhibit biofilm formation of S. flexneri_14. Scanning electron microscopy analysis presented that the cell membrane permeability of S. flexneri_14 was demolished by LFX01, leading to cytoplasmic contents leakage and cell rupture death. In summary, a novel bacteriocin of lactic acid bacteria (LAB) was found, which could effectively control S. flexneri in both planktonic and biofilm states.

Dual infections of tilapia parvovirus (TiPV) and tilapia lake virus (TiLV) in multiple tilapia farms: Their impacts, genetic diversity, viral tropism, and pathological effects

Tilapia culture is an essential protein-rich food production sector worldwide. The emergence of pathogens is sometimes associated with fatal outbreaks in tilapia, which dramatically slow production and result in severe economic losses. While tilapia lake virus (TiLV) infection has been associated with fatal diseases in tilapia, the novel tilapia parvovirus (TiPV) has been recently identified and reported to be associated with mass mortality events in tilapia farming. In this study, we identified the coinfection of a novel TiPV and TiLV in multiple independent tilapia farms in Thailand, thus causing significant losses. The full-length genomes of the TiPV were characterized, and a phylogenetic analysis was performed, indicating the genetic diversity of the TiPV and multiple amino acid mutations found in the structural protein VP1. Using the in situ hybridization (ISH) technique, TiPV was localized in the gills, heart, brain, liver, pancreas, spleen, intestine, kidney, eyes, and muscles of tilapia, with evidence of cellular tropism. The TiLV localization was confirmed using a dual ISH/immunohistochemistry protocol and transmission electron microscopy, which indicated a potential association with pathological alterations. Both TiPV and TiLV were successfully propagated in tilapia brain cells and the fish cell line E-11. This study also provided an indication of the potential cellular roles of the pathological features of TiPV coinfection with TiLV in red hybrid tilapia. Since mutations in the parvovirus structural protein led to virulence and extensive infection in susceptible hosts, several point mutations in the VP1 gene with amino acid signatures of TiPV found in tilapia in Thailand warrant future observations. Although the synergism between TiPV and TiLV coinfection remains undetermined, the contributory role of these two viruses requires intensive focus. Further investigations should lead to a suitable strategy for disease control.

Expression of immune-related genes in parasite-infected Tilapia nilotica (Oreochromis niloticus) from Egypt and molecular characterization of the parasites

Aquaculture is one of the world's most rapidly developing animal production sectors. Tilapia nilotica (Oreochromis niloticus) is the most popular fish known for quality and price. In the present study sixty fish samples of Tilapia nilotica (Oreochromis niloticus) of about 16-22cm length were collected from Tilapia breeding farms and twenty Nile tilapia fish samples were collected for tissue sampling rom each farm. Fish samples were thoroughly investigated for external parasites by visual inspection microscopically through fixed wet smears from the gills and skin. The DNA was extracted from the fish and 17 different parasite species were amplified for partial 18S rDNA and entire ITS1 regions using three sets of commonly recommended primers. The amplicons were confirmed through sequencing. The results exhibited that Trichodina sp. and Gyrodactylus hildae in gills, Cichlidogyrus aegypticus on skin while Acanthosentis sp. was found in the intestine of infected tilapia within Fuwa City, Kafr El sheikh Governorate. The parasites found in Mataria City, Dakahlia Governorate were Cichidogyrus halli on the gills, Zschokkella candia on muscles, and Clinostomum tilapiae in the intestine. The parasites Dactylogyrus sp. and Myxobolus fomenai were recovered from the skin and muscles, respectively, of infected Tilapia from King Mariout, Borg El-Arab City, Alexandria Governorate. Moreover, the expression level of IL-1β gene was up-regulated in muscle, skin, gills and intestine tissues of fish infected with parasites such as Z. candia, C. halli, C. tilapiae, Dactylogyrus sp., M. fomenai, C. aegypticus, Trichodina sp., G. hildae, and Acanthocentis. The similar up-regulation tissues expression trends of TNF-α and IFN-γ genes were found in fish infested with these parasites. The present study exlored molecular characterization of different parasites isolated in different locations of Egypt in Tilapia nilotica (Oreochromis niloticus) and up-regulation of the inflammatory response genes such as IL-1β, TNF-α and IFN-γ is an indicator of the sever inflammation due to these parasitic infestation in fish.

The Role of Salinity in Histopathology Description of Jatim Bulan Tilapia Juvenile (Oreochromis niloticus) Exposed by Lead (PB)

The decrease in the number of lands for aquaculture will cause the freshwater fish aquaculture, especially tilapia is reared. As one of the efforts to survive, the breeders use the coastal area to anticipate, so the freshwater fish can adapt to the sea waters. Heavy metal pollution near the coasts (or in the coastal waters) has great potential impacts on the environment. The present study aimed to find out the effect of Lead (Pb, heavy-metal) exposure on the Jatimbulan Juvenile tilapia with the different salinity towards histopathology description of the gill, intestine, and the skin tissues. The method used was an experimental method with a completely randomized design using six treatments and three times repetition. The observed parameters included the changes in histopathology description of gill, intestine, and skin organs of Jatimbulan juvenile tilapia. Kruskal-Wallis scoring method was used for data analysis and was continued by Mann-Whitney. The result of the current study showed the effect of salinity towards histopathology description of gill, intestine, and skin of Jatimbulan juvenile tilapia. The effect of changes was proven with the histopathology description in the form of the damage of edema, hyperplasia, and necrosis on the gill tissue; the damage of edema, atrophy, and necrosis on the gill tissue as well as the damage of edema, atrophy, hemorrhagic and necrosis on the gill tissue. From the result of the current study which has been conducted, it can be concluded that the heavy-metal exposure by lead was 0.03 ppm on the salinity of 10 ppt and 20 ppt. given the significant effect on the histopathology description of gill, intestine, and skin of Jatimbulan juvenile tilapia.

Evaluating the addition of starry triggerfish (Abalistes stellaris) bone charcoal as a feed supplement to the growth performance and intestinal villi length of nile tilapia (Oreochromis niloticus)

Nile tilapia is a freshwater fish that is widely cultivated in Indonesia. During its development, tilapia aquaculture has constraints such as low growth rates. Therefore, it is necessary to add a feed additive to the feed in the form of charcoal. Charcoal is an adsorbent that has high absorption so that the addition of charcoal in the feed can increase the absorption of nutrients of tilapia. A 45-days trial was conducted to determine the percentage of addition of triggerfish bone charcoal (Abalistes stellaris) as a feed supplement that affect the growth performance and intestines of tilapia. The research design was a non-factorial Completely Randomized Design (CRD) with 4 treatments and 2 replications as treatments including: treatment A (control), B (addition of 1%charcoal), C (addition of 2% charcoal) and D (addition of 3% charcoal). A total of 240 tilapia fingerlings (5-7 cm) were used and placed in 8 aquariums then filled with 72 liters of water. Providing adlibitum (unlimited) feed with a frequency of 2 times a day. The ANOVA test showed that the addition of triggerfish bone charcoal (A. stellaris) in the feed was not significantly different (P 0.05) in weight growth, absolute length and daily length growth but it was significantly different (P 0.05) in feed conversion ratio and the efficiency of feed utilization. Based on result, it was concluded that the addition of 3% charcoal was the best treatment which gave the lengthiest of villi which was increasing the length of the intestinal villi to 71.11 µm from the initial length of 162.22 µm. easel at 233.33 μm, showed the highest feed conversion ratio value and feed efficiency (1.12 %, 89.6%).Keywords:CharcoalFish boneIntestinal histologyStarry triggerfish

Modulation of growth, skin mucus and serum immunities, and disease resistance of Nile tilapia fed host‐associated probiotic (Lactobacillus paracasei l61‐27b)

The experiment was performed to examine the effect of Lactobacillus paracasei l61-27b (LP) isolated from Nile tilapia intestine on the growth rate, skin mucus and serum immune parameters and disease resistance. Fish (25.40 ± 0.33 g) were distributed into glass tank (150 litres tank−1) at 20 fish tank−1 and fed with different levels of dietary L. paracasei l61-27b: 0 (LP1), 106 (LP2), 107 (LP3), 108 (LP4) and 109 CFU mL−1 (LP5) for 8 weeks. The results indicated that SGR, WG and FW significantly improved, while FCR significantly decreased, in fish fed LP supplemented. Dietary L. paracasei significantly increased SMLA and SMPA with the highest values recorded for fish in LP4 and LP5 groups. Similarly, SL, SP, ACH50, PI and RB were significantly stimulated in fish fed LP diet compared with fish fed control diet. Challenge study showed that in comparison with the control diet (20% survival), the survival rates of fish fed the L. paracasei were significantly (p < 0.05) higher; by 63.33% (LP2), 66.67% (LP3), 80.00% (LP4) and 83.33% for LP5. The relative per cent survival (RSP) was 54.17%, 58.33%, 75% and 79.17% in LP2, LP3, LP4 and LP5, respectively. In conclusion, the dietary inclusion of L. paracasei can be potentially used in Nile tilapia to improve its growth and health status.