Catfish Clarias Macrocephalus Research Articles

Transcriptome response of pubertal male Clarias macrocephalus to dietary 17α-methyltestosterone

We studied the mechanism of the effects of 17α-methyltestosterone (MT) on previously reported enhanced growth and maturation of the Asian catfish Clarias macrocephalus. A total of 18 pubertal male (3 fish·tank-1) catfish (ABW=125.97 g) were stocked into six experimental circular tanks and fed with a basal diet (control) or a basal diet containing 60 mg MT kg-1 diet for 90 days. At the termination of the experiment, livers were excised, and total RNA was extracted, evaluated, and reverse transcribed to cDNA. Six libraries of cDNA (3 for the control and 3 for the MT-treated group) were subjected to bioinformatics. Differentially expressed genes (DEGs) were identified using similarity scores of the de novo assembled transcript with those in the seven public databases. There were 141 up- and 72 down-regulated DEGs, mostly belonging to uncharacterized/not yet identified proteins. Thus, DEGs in the top enriched KEGG pathways were used to characterize the effects of MT. Upregulated DEGs included tyrosine hydroxylase (TH), Cytoplasmic Polyadenylation Element Binding (CPEB), Fas-associated death domain (FADD), Major Histocompatibility Complex class 1 (MHC-1), other immune-related genes, among others. Down-regulated DEGs included Cytochrome P450 family one subfamily A member 1 (CYP1A1), Alternative oxidase (AOX), UDP-glycosyltransferase (UGT), Acyl-CoA Synthase Bubblegum Family Member 1 (ACSBG), Stearoyl-CoA Desaturase (SCD), among others. In conclusion, MT-treated male Clarias macrocephalus exhibited up-regulation of some pathways protecting cellular conditions like cell proliferation, survival, development and homeostasis processes, for development and homeostasis processes. MT also affected changes in bile acid production and the inhibition of the production/conversion of testosterone. MT resulted in the down-regulation of a serotonergic system that possibly affected gonadal development, inhibition of the retinoid enzyme that would otherwise diminish the full effects of MT or its metabolite, and inhibition of the formation of estrogen, leading to down-regulation of several estrogen-related KEGG pathways.

Benfotiamine in high carbohydrate diet enhances growth and reproductive performance of the Asian native catfish Clarias macrocephalus subadults

Clarias macrocephalus has been extirpated in most regions in the Philippines and as a preliminary study towards its reintroduction, we aimed at enhancing the growth and reproductive performance of the broodstock. Several studies have identified thiamine deficiency as a factor in the extirpation of some important fish species in the wild. The present study aimed to determine the effects of elevated dietary carbohydrates and benfotiamine, a more bioavailable analog of thiamine (vitamin B1). Three diets were used, namely, a commercial diet specific for catfish was used as the control diet (Com), a high carbohydrate (HC) diet, and a benfotiamine-supplemented HC diet (HCB). Results show that survival of the subadult catfish in captivity for 10 weeks was remarkably high, exhibiting an average of 99% for all three treatments (P>0.05). HCB diet resulted in significantly higher final average body weight (FABW), weight gain (WG), specific growth rate (SGR), and significantly best food conversion ratio (FCR) (P<0.05) than the values for both Com and HC groups (P>0.05). For the reproductive performance, female Asian catfish fed the HCB diet exhibited significantly heavier ovary and liver (P<0.05) than those female catfish fed either the Com or HC diet (P>0.05). GSI of the female catfish and fecundity were significantly higher in the HCB group (P<0.05) than in the Com or HC group (P>0.05). In the male catfish, testes were significantly heavier in the HCB group (P<0.05) than in the Com or HC diet (P>0.05). HSI, male LW, and LL were significantly higher in the HC and HCB groups (P>0.05) than in the Com group (P<0.05). GSI values of the male catfish were significantly highest in the HCB (P<0.05), followed by the HC group, and significantly lowest in the Com group (P<0.05). The larval survival rate for one week was significantly higher (P<0.05) in the Asian catfish fed the HCB diet than in those fed the Com or HC diet (P>0.05). In conclusion, elevating dietary carbohydrates in the diet from 7.70% to 22.73% (i.e., Com to HC diet, respectively) did not negatively affect the growth and reproductive performance of the Asian catfish. Further supplementation of benfotiamine at 0.02% to the HC diet enhanced significantly both the growth and reproductive performance of the Asian catfish.

Characterization of Antioxidant Peptides from Thai Traditional Semi-Dried Fermented Catfish

Herein, the antioxidant peptides from a Thai traditional semi-dried fermented farmed hybrid catfish (Clarias macrocephalus × Clarias gariepinus) catfish, Pla Duk Ra, were characterized. After extraction and deproteinization, Pla Duk Ra crude peptide extract (CPE) was fractioned using 2 connected Hitrap Sephadex-G25 columns, yielding two significant fractions, F1 with higher browning intensity (A420) and F2. CPE, F1, and F2 had different amino acid profiles, contents, and sequences evaluated by LC-MS/MS, which could be responsible for their antioxidant properties. F2 contained the highest numbers of hydrophobic amino acid (HBA) (47.45%) and aromatic amino acid (27.31%), followed by F1, and CPE. The peptides with 8–24 amino acid residues were detected in CPE and its fractions. In CPE, F1, and F2, there were 69, 68, and 85 peptides with varied HBA content, respectively. ARHSYGMLYCSCPPND (50% HBA), ALRKMGRK (37.5% HBA), and ANWMIPLM (87.5% HBA) were the most prevalent peptides found in CPE, F1, and F2. Overall, F2 was the most effective at inhibiting free radicals (DPPH● and ABTS●+) and reactive oxygen species (hydroxyl radical, singlet oxygen, and hydrogen peroxide), followed by F1 and CPE. The metal chelation of F1 was, however, superior to that of F2 and CPE. For the stability test, the effects of pH, heating temperature, and in vitro digestion on the DPPH● scavenging activity of F2 were investigated. The activity was boosted by lowering the pH and raising the heating temperature. In the gastrointestinal tract model system, however, roughly 50% of DPPH● scavenging activity reduced after digesting.

High genetic structure between natural populations of bighead catfish Clarias macrocephalus (Günther, 1864) from the Mekong Delta and Peninsular Malaysia

The tropical freshwater bighead catfish Clarias macrocephalus is widely distributed in Southeast Asia and is economically important in both the aquaculture and fisheries industries. In the current study, eight polymorphic microsatellite markers were employed to evaluate the genetic variation of 15 C. macrocephalus populations from Peninsular Malaysia, and the Mekong Delta populations of Cambodia and Vietnam. Overall, the number of alleles in C. macrocephalus populations ranged from 1 to 25 alleles. In general, genetic diversity was higher in the mainland populations (Cambodia, HE = 0.761 to 0.813 and Vietnam, HE = 0.759 to 0.789 with mean number of alleles of 10.13–13.88) compared to Peninsular Malaysia (HE = 0.519 to 0.699 with mean number of alleles of 4.5–10.75). High linkage disequilibrium and deviation from HWE suggest inbreeding in most Peninsular Malaysia populations which was also reflected by significant FIS values (0.217 to 0.410, p < 0.05). All pairwise FST (p < 0.05) values were significant. No evidence of bottlenecks was detected among all populations. The 15 populations formed two evolutionary units; Peninsular Malaysia versus the Mekong Delta-Cambodia and Vietnam. The findings from this study will serve as a reference for a systematic aquaculture programme and the conservation and management of wild populations of C. macrocephalus.

Evaluation of two extant population sources of Clarias macrocephalus using liver transcriptomic profiles towards reintroduction

There is a need to evaluate and choose a possible population source of the threatened catfish Clarias macrocephalus for possible reintroduction into aquaculture. Identifying gene transcription profiles that provide fitness benefits in specific environments would promote more effective species reintroduction and conservation practices. In this study, comparison of hepatic transcriptome profiles was made in terms of expression patterns of various growth-, immune- and reproduction-related genes of two Clarias macrocephalus strains from Cagayan (CmC) and Agusan del Sur (CmA), located in the Northern and Southern Philippines, respectively. RNA sequencing results showed that there were 13,138 differentially expressed genes (DEGs) identified in CmA vs. CmC, of which 6,795 DEGs exhibited significant upregulation while 6,343 DEGs displayed significant downregulation. From this pool of DEGs, numerous immune- (complements C3, C4, C7), growth- (glutamine synthetase, GLUL; glycogen synthase, GYS; elongation of very long chain fatty acids protein 6, ELOVL6, lipoprotein lipase, LPL) and reproduction-related (vitellogenin, VTG; cytochrome p450 19b-like, CYP19b; progesterone receptor, PGR) genes were identified. Pathway enrichment analysis revealed the enrichment of the complement component and coagulation cascades, protein digestion and absorption and lipid metabolism pathways. Results of this study indicated that when reintroduction was to be done, C. macrocephalus population from Agusan Marsh is predicted to grow much faster because of up-regulated growth-related genes, to be more resistant to pathogens/environmental stressor as it manifested up-regulated immune-related genes and to reproduce better as reflected by its up-regulated reproduction-related genes than its counterpart catfish from Cagayan.

Electrical Activity and Predation in the Clariid Catfish Clarias macrocephalus (Clariidae) Exposed to Varying Illumination

The influence of illumination (light–dark) on electrical emission in a clariid catfish Clarias macrocephalus hunting fast-moving prey (guppies Poecilia reticulata) has been studied. A total of five types of electrical events has been registered, of which monopolar electrical pulses are classified as specialized electrical discharges. Pulses with multiple polarity reversal and long duration are myograms accompanying the locomotor activity of fish. Pulses with noticeable ruggedness, brief pulses, and a series of pulses can be considered intermediate between the two categories of electrical discharges. The emission of electrical discharges occurs mainly in the dark, which corresponds to the daily feeding chronology in clariid catfishes. It has been first shown that catfish can emit all types of electrical events, including specialized discharges, even when a single fish is isolated. The obtained results confirm that clariid catfish belongs to the weakly electric fishes with episodic emission of specialized electrical discharges. The evolutionary pathway of electric fishes from nonelectric ancestral forms with episodic unspecialized emission of nonsynchronized action potentials to forms that emit more and more synchronized action potentials and further to specialized electric fishes, including strongly electric ones and/or those using electrical discharges for location and communication, is discussed.

Evaluation of Houttuynia cordata Thunb. leaf extract on growth performance, feed utilization, and hematological indices of hybrid catfish (Clarias macrocephalus × Clarias gariepinus)

This research evaluates the effects of Houttuynia cordata thunb. leaf extract on growth performance, feed utilization and the hematological indices of Hybrid catfish (Clarias macrocephalus × Clarias gariepinus). Four groups of fish were divided and given a basal diet (control group) as well as the extract solution, which was sprayed into the commercial fish feed (30% crude protein) in the amounts of the extract, 50, 70 and 100 ml/kg feed, then fed to the experimental fish for 90 days. Dominant results for the growth indices were found on days 15 and 30 of the experimental period. A significantly increased level (p < 0.05) of average daily growth (ADG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER), as well as the lowest feed conversion rate (FCR), were found in fish fed with H. cordata extract at 70-ml/kg feed on day 15. While on day 30, it was revealed that the ADG, SGR, and PER were at their highest values in fish fed 50 ml/kg. Meanwhile, the survival rate was significantly different only at the end of the experiment (day 90) and was at its highest rate in the group fed 100 ml/kg. The highest total red blood cell levels (RBC) were observed in groups fed 70 and 100 ml/kg of feed over 30 days while the highest RBC levels on day 60 were found in groups that were fed 50 and 70 ml/kg. Total white blood cell (WBC) levels were at the highest significant value (p < 0.05) in fish fed 70 ml/kg on days 30, 60, and 90 when compared with the control group. Hematocrit percentage (Htc) showed only a significant difference on day 30 and the highest level was observed in fish fed 70 ml/kg. Fish fed 50 and 70 ml/kg of feed had a significantly affected increase in lymphocyte, monocyte, eosinophil, basophile, and neutrophil levels but thrombocyte levels fluctuated. Based on our findings, we can assert that H. cordata leaf extract is suitable for application in the fingerling nursing step. This was especially seen during the first 30 days of the experiment, which showed that significantly higher values of growth indices could be achieved. Moreover, the extract should be looked at further in terms of its application for immune stimulation in fish, because different white blood cell types were increased by H. cordata leaf extract.

Use of microsatellite markers in differentiating catfish hybrids (Clarias macrocephalus x C. larias gariepinus) from their parental species

This study aimed to develop microsatellite markers that can be used to differentiate catfish hybrids (bighead catfish Clarias macrocephalus x African catfish C. larias gariepinus) from their parental species. Microsatellite primers developed from previous studies were screened and optimized. Six microsatellite markers were selected to amplify samples of bighead catfish (n = 37), African catfish (n = 29), and the hybrids (n = 30). Results show that 4 of 6 loci differ in allele numbers and sizes between the bighead and African catfish. In the other two loci, these two species share one allele that overlaps at a portion of the size range with different allele frequencies. Hybrids’ genotypes are intermediate between those of the parental species. The genetic divergence between bighead and African catfish is high with Fst = 0.59 and Rst = 0.95. Therefore, these 6 microsatellites were applied to successfully distinguish hybrids from their parental species with high accuracy.

The Effect of Dietary Carotenoids of Different Forms: Microemulsified and Non-microemulsified on the Growth Performance, Pigmentation and Hematological Parameters in Hybrid Catfish (Clarias Macrocephalus × Clarias Gariepinus)

We tested the feasibility and effect of including dietary carotenoids of different forms, microemulsified (MY) and non-microemuslified (NMY), in diets for hybrid catfish (Clarias macrocephalus × Clarias gariepinus). The results showed that the abdominal skin and back muscle yellowness (b*) of fish fed with 0.7 kg/t MY was higher than the other treatments (1.0 kg.t NMY and control) (p<0.05) with a score of 8.30 and 16.33 respectively. This group also gave the highest total carotenoid deposited in the muscle of 88.27 mg/kg. Carotenoid addition to the control diet at 1.0 kg/t NMY and 0.7 kg/t MY dosage have no adverse effect on the growth, in fact they helped to improve the body weight gain by 82.98 g and 84.17 g (p<0.05) with an FCR improvement of 13 points and 16 points (p<0.05) respectively. There was no adverse effect on the immune system after feeding carotenoid to the catfish and enhancement was observed in certain immune response indices when compared to the control. The findings in the present study were very significant because it supported that microemulsified yellow carotenoids (with smaller particle size of ~0.25 μm) and when used at lower inclusion rate of 30% could achieve better overall performance when compared to the regular size carotenoids and control due to its enhanced bioavailability.

Electrical activity of the broadhead catfish Clarias macrocephalus during paired aggressive-defensive interactions: Effects of illumination and chemical alarm signal

We studied the effects of illumination and alarm pheromone on emition of specialized electric discharges in the broadhead catfish Clarias macrocephalus (Clariidae, Siluriformes) during aggressive-defensive interactions. The discharges were recorded with a special hardware in two adult fish of a similar size placed into an aquarium, during a period of 24 h, under alternating 30-min-long light (700 lx) and dark periods. The electrical activity of the broadhead catfish was found to be higher in the dark than under the light; by the end of the trial, the frequency of electrical discharges gradually decreased. The overall number of discharges recorded in different pairs of the fish was significantly different, which is evidence of individual variability in the electrical activity. Changes in the illumination regime in many cases increased the emition of electrical discharges, which could be a result of a stress-response. However, the stimulation of the fish by alarm pheromone (extract of the skin, 0.5 g/l) caused no pronounced changes in the electrical activity. It is supposed that aggressive motivation caused in the broadhead catfish by the presence of another individual of the same species dominated over the defensive response initiated by the alarm pheromone and, thus, dominated in the development of the electrical response.

Assessment of the invasive catfishPterygoplichthys pardalis(Castelnau, 1855) in Thailand: ecological impacts and biological control alternatives

A species of Neotropical suckermouth armored catfish (family Loricariidae), tentatively identified as the Amazon sailfin catfish Pterygoplichthys pardalis, is a highly invasive, non-native species in Southeast Asia. In Thailand, the spread of P. pardalis is an increasing concern because of the possibility that these non-native catfish are negatively impacting freshwater biological resources. In this study, we conducted a series of laboratory experiments to investigate the food preferences of P. pardalis as well as the interactions of this catfish with the native bighead catfish Clarias macrocephalus (Gunther, 1864). We also conducted laboratory experiments to evaluate the potential use of three different native piscivorous fishes as biological control agents. Laboratory results revealed that P. pardalis in aquaria conditions readily consumed the eggs and fry of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) and that large specimens P. pardalis preferred O. niloticus eggs over Tubifex worms. Pterygopl...

Growth and morphological development of laboratory-reared larval and juvenile bighead catfish Clarias macrocephalus (Siluriformes: Clariidae)

Morphological development in laboratory-reared larval and juvenile bighead catfish Clarias macrocephalus is described. Body length (BL) of larvae and juveniles was 3.4 ± 0.3 (mean ± SD) mm just after hatching, reaching 11.3 ± 1.0 mm by day 16, and 24.2 ± 2.8 mm by day 40. Overall aggregate fin ray numbers (except for caudal fin procurrent rays) attained full complements by 15.2 mm BL. Gill buds appeared on day 0, those of barbels (four pairs) and primordial nostrils on day 1, and pectoral fins on day 3. All larvae began feeding by day 3. Conical teeth were observed on day 7. Notochord flexion began on day 2, the yolk being completely absorbed during days 7–9. Melanophores were scarce at hatching, increasing with growth to cover almost the entire body except the ventral surface of the abdominal cavity. Proportions of head length, pre-anal length, body depth, eye diameter, and maxillary barbel length became relatively constant after yolk absorption, those of snout length and upper jaw length increasing until ca. 12–13 mm BL and decreasing thereafter. Suprabranchial organ started developing in postflexion larval stage larger than ca. 11.0 mm BL (day 16), and air-breathing was suggested to be functional at that time.

Ejection of specialized electric discharges during prey pursuit and unspecialized electric activity related to respiratory behavior of the clariid catfish Clarias macrocephalus (Clariidae, Siluriformes)

Ejection of specialized electric discharges during prey pursuit and unspecialized electric activity related to respiratory behavior of the clariid catfish Clarias macrocephalus (Clariidae, Siluriformes)

Microsatellite-centromere mapping in walking catfish Clarias macrocephalus (Günther, 1864) using gynogenetic diploids

Thirty new microsatellite loci were isolated from a microsatellite-enriched genomic library of walking catfish Clarias macrocephalus. The CA motif was the most abundant, although several other motifs were also isolated. Two gynogenetic diploid families, each consisting of a female and 50 offspring, were genotyped at 56 microsatellite loci, including 30 loci developed in the present study and 26 loci reported in the previous study. Overall, 33 anonymous microsatellites derived from genomic library and 11 EST-linked microsatellites were mapped to their centromeres. High levels of chiasma interference were apparent in the walking catfish genome as indicated by an average frequency of second-division segregation (y) of 0.643 ± 0.248. Twenty-six loci (59%) showed a high microsatellite–centromere recombination, with a frequency >0.67, and three loci had recombination frequencies >0.9. This study demonstrated that gene–centromere mapping provided a rapid method for the expansion of the initial linkage map of walking catfish.

Expression of four muscle proteins at different growth stages of Günther's walking catfish Clarias macrocephalus

The complete cDNA sequences of four contractile muscle genes of walking catfish Clarias macrocephalus were characterized by assembling partial EST sequences from a skeletal muscle cDNA library. The four genes were parvalbumin 4 (PV4) (670 bp), troponin C (TnC) (1065 bp), troponin I (TnI) (843 bp) and myosin light chain 3 (MLC3) (953 bp), leading to deduced amino acid sequences of 109, 160, 176 and 150 residues respectively. During the larval stage, TnC mRNA showed the highest levels of expression with a 1.4-fold increase from day 1 to day 30 post hatch. At 90 days, the relative expression levels of PV4, TnC and MLC3 were the highest, with similar proportions in the skeletal muscle, corresponding to the highest relative growth rate of walking catfish. Expression of the three calcium-binding proteins remained high in 6-month-old fish, with higher levels of PV4. The different proportions of muscle proteins expressed suggested the significance of their contributions to fish growth and appeared to be correlated with the functional properties of muscle cells, which were observed from changes in the swimming activity of the fish.

Electrical activity of asian catfish Clarias macrocephalus (Claridae, Siluriformes) during spawning behavior

Electrical activity of asian catfish Clarias macrocephalus (Claridae, Siluriformes) during spawning behavior

Use and exchange of aquatic genetic resources in aquaculture: information relevant to access and benefit sharing

Use and exchange of aquatic genetic resources in aquaculture: information relevant to access and benefit sharing

Textural Properties of Gel Made from Hybrid Catfish (Clarias macrocephalus x C.gariepinus) Fillets Chilled in Ice and at Temperature of 4 ÌC

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Molecular characterization and seasonal expression of the vitellogenin gene from Günther's walking catfish Clarias macrocephalus

The complete cDNA sequence for walking catfish vitellogenin (VTG) (4192 bp) contained 51 bases of 5′-untranslated region, an open reading frame of 4050 bp encoding 1350 amino acids, 60 bases of 3′-untranslated region, and a poly(A) tail of 31 nucleotides. The deduced amino acid sequence of walking catfish VTG shared 58.9%, 56.9%, 41.7%, 32.6% and 8.1% identity with VTGs of common carp, zebrafish, rainbow trout, Xenopus and chicken, respectively. Results agreed with previous studies which indicated that among fishes, VTG is not a highly conserved protein, but shares a common general structure. Northern blot and RT-PCR revealed that VTG was specifically expressed in the liver of female fish. To establish the relationship between gonadosomatic index (GSI) and the level of hepatic VTG transcript, monthly change in the GSI of females was monitored over a 1-year period from June 2006 to May 2007. The relative copy number of VTG mRNA was determined by quantitative real-time PCR. Significant variations of mean GSI values and VTG mRNA levels (P<0.05) were observed among months. From June to August, mean GSI values ranged from 8.60±0.35% to 13.07±0.59%. Highest mean GSI value (18.27±2.51%) and maximum VTG transcript levels were observed in September. From October through March, ovarian weight steadily declined, with the lowest mean GSI value (0.77±0.38%) in January. The expression profile of the VTG gene reflected the annual changes in reproductive cycle of female walking catfish, showing high levels during the breeding period and low levels during resting periods.

Bioaccumulation of cadmium in an experimental aquatic food chain involving phytoplankton ( Chlorella vulgaris), zooplankton ( Moina macrocopa), and the predatory catfish Clarias macrocephalus × C. gariepinus

The accumulation of cadmium (Cd) was studied in an experimental aquatic food chain involving the phytoplankton Chlorella vulgaris as the primary producer, the zooplankton Moina macrocopa as the primary consumer, and the catfish Clarias macrocephalus × Clarias gariepinus as the secondary consumer. C. vulgaris was first exposed to Cd solutions at 0.00, 0.35, and 3.50 mg l −1, referred to as control group and experimental groups 1 and 2, respectively. Subsequently, each group was fed to three corresponding groups of M. macrocopa. Finally, three groups of catfish were fed these corresponding groups of M. macrocopa. After C. vulgaris was exposed to 3.50 mg l −1 Cd (experimental group 2), the residual Cd in solution was only 4.01 μg l −1, lower than the maximum allowable limit of Cd in natural water sources (5 μg l −1). Cd concentrations in C. vulgaris were 0.01 ± 0.00 μg g −1 (dry wt) in the control group, 194 ± 1.80 μg g −1 (dry wt) in experimental group 1, and 1140 ± 20.06 μg g −1 (dry wt) in experimental group 2. The Cd concentrations in M. macrocopa were 0.01 ± 0.00 μg g −1 (dry wt) in the control group, 16.48 ± 2.23 μg g −1 (dry wt) in experimental group 1, and 56.6 ± 3.23 μg g −1 (dry wt) in experimental group 2. The Cd concentrations in catfish muscle increased with increasing Cd concentrations in the food. After 60 days of fish culture, the mean concentrations of Cd in fish muscle were 0.01 ± 0.00 μg g −1 (dry wt) in the control group, 0.61 ± 0.02 μg g −1 (dry wt) in experimental group 1 and 1.04 ± 0.06 μg g −1 (dry wt) in experimental group 2. Cd concentration in fish muscle of experimental group 2 was equal to the permissible limit. Cd accumulation affected fish growth: at the end of the study, the mean fresh weight (12.81 g) of catfish in the control group, was significantly higher than those experimental group 1 (10.43 g) and experimental group 2 (10.00 g). The results showed that the measurement of Cd concentration in water does not necessarily give a measure of the safety of aquatic organisms as human food. Hence, heavy metal contamination is a matter for concern when organisms are harvested, for fish and human consumption, from natural water sources.