Betta Research Articles

MOLECULAR DETECTION OF MEGALOCYTIVIRUS GENOTYPE: INFECTIOUS SPLEEN AND KIDNEY NECROSIS VIRUS IN MALAYSIAN OVIPAROUS AQUARIUM FISH

The Malaysian ornamental fish industry’s recent production is recorded at RM350 million per annum. An Infectious Spleen and Kidney Necrosis Virus (ISKNV), one of the Megalocytivirus strains has been related to significant systemic infections that has ravaged ornamental fish stocks and had a severe financial impact on businesses in the sector. It is vital to identify Megalocytivirus host species among Malaysian oviparous ornamental fish as the virus can cripple the ornamental fish trade which is a major contributor to the country’s export trade. The purpose of this research is to determine the prevalence of Megalocytivirus, ISKNV strain in oviparous aquarium fish, Betta splendens, Danio rerio, Trichogaster lalius, Hyphessobrycon anisitsi and Puntigrus tetrazona in Malaysia. The DNA of the Megalocytivirus in the samples was detected using the nested polymerase chain reaction (PCR) method. Out of 239 samples collected in January 2019 and January 2020, six pooled samples (n=30) tested positive for ISKNV infections in D. rerio and T. lalius. Positive P. tetrazona samples in this study showed a distended abdomen as the only observable clinical sign whereas all other samples were asymptomatic. All the positive samples were similar to each other. In terms of the nucleotide identity of the ISKNV, which stood at between 98% and 100%. In conclusion, the positive samples can be categorised into Megalocytivirus genotype I.

Assessing Genetic Diversity of Wild Populations and Different Color Varieties for Genetic Improvement of Siamese Fighting Fish Betta splendens in Thailand.

To establish sustainable resources and founder populations for genetic improvement of the Siamese fighting fish Betta splendens, genetic diversity in wild and hatchery stocks was examined using mitochondrial (mt) DNA genes cytochrome b (cytb), 16S ribosomal DNA (16S rDNA), and cytochrome oxidase subunit I (COI), and eight microsatellite loci. Based on mtDNA sequences, restrictive levels of polymorphism (0, 3, and 1 substitutions) were observed in this study. For analysis of microsatellites, fluorescent multiplex PCR was developed, and subsequently identifying moderate levels of observed (Ho = 0.4488) and expected (He = 0.6627) heterozygosities and a high number of alleles per locus (15.125 alleles) for overall samples. Comparison of Siamese fighting fish from different sources revealed large genetic differences between pairs of farmed fish (eight groups) and between wild (three geographic locations) and farmed fish (P < 0.0031 following Bonferroni correction). This suggested limited exchanges of genetic resources between commercial farms. When different color varieties of B. splendens were compared, large genetic distances and significant FST estimates and genetic heterogeneity were found (P < 0.0031). Effective population sizes (Ne) were estimated and two farms (NP2-2BS and BK1-4BS) showed Ne greater than 10. Among color varieties, Multi-colors and Blue revealed reasonable Ne (large and 27.9), but lower Ne values (3.6-8.4) were found for the remaining color varieties. These results indicate an urgent need for the establishment of gene pool resources of B. splendens for effective genetic improvement of Siamese fighting fish in Thailand.

Transcriptome comparison for identification of pigmentation-related genes in different color varieties of Siamese fighting fish Betta splendens

Transcriptome comparison was performed to identify genes expressed in skin, muscle and tails of mono-color (Red, Blue, Black, White and Yellow), bi-color (Cambodian) and multi-color (Marble) varieties of Siamese fighting fish Betta splendens. In total, 163,140 unigenes covering 26.348 Gb were found. Of these, 93,899 (57.55 %) unigenes significantly matched at least one database. In total, 5039 differentially expressed genes (DEGs) were found where 2415 genes (47.93 %) showed higher expression and 2624 genes (52.07 %) showed lower expression for all pairwise comparisons. DEGs between paired color varieties were 133–443. Of these, 38–220 genes were more highly expressed while 37–280 genes were more lowly expressed relative to the compared varieties. A total of 897 sequences (148 genes) significantly matched pigmentation-related genes of Danio rerio (E-value < 1e-06). Of these, 19 DEGs were identified. Examples are tyrosinase-related protein 1a (BsTyrp1a), epidermal growth factor receptor (BsEgfr) and neurofibronin 1a (BsNf1a). Moreover, 711,123 SNPs were identified and 1365 of these were located in pigmentation-related genes. Interestingly, an A > C474 SNP in the gene BsTrpm7 and an indel (position 3571) in the BsItgb1a gene were found only in Cambodian. A C > T2520 SNP in BsFzd4 and 10 of 11 SNPs in BsTyrp1a were found only in Black. Different expression levels (P < 0.05) were found for tyrosinase (BsTyr), BsTyrp1a, BsNf1a and BsEgf1 among skin, body muscle and tails of the same variety and among the same tissues of different varieties (Red, Green, Blue, Black, Cambodian and Multi-colors, N = 5 each).

Baseline study on the freshwater ornamental fish industry in Palawan, Philippines

The status of both freshwater and marine ornamental fish industries in the Philippines has been assessed in 2019; however, Palawan was excluded due to the unavailability of data with regard to the ornamental fish trade. Hence, this study collected baseline data on the freshwater ornamental fish industry specifically the distribution of freshwater ornamental fish hobbyists, socio-demographic profile of the respondents, the key players involved in the market chain, classification and number of fish species and strains involved, and the challenges (economic and scientific) and opportunities encountered by the key players which could be used for the improvement and development of the ornamental fish sector in Palawan. A poll was conducted in order to obtain information on the general location of the ornamental fish hobbyists in Palawan in which 77 individuals participated. An online survey form was then sent to participants, however, only 40 responded. The freshwater ornamental fish hobbyists were distributed in 11 localities of Palawan. Key players involved in the market chain of freshwater ornamental fish were categorized as producers, traders, and sellers. Twelve freshwater ornamental fish species with 83 strains/varieties were involved, dominated by the Siamese fighting fish and guppy. Economic and research problems were some of the problems cited by the key players.

Oxytocin reduces the frequency of aggressive behaviours in male betta fish (Betta splendens)

The objective of this study was to evaluate the effect of visual isolation and the influence of oxytocin on the aggressive behaviour of male Betta splendens and produce an ethogram for analyses. In the first stage, the fish (n = 6) were kept for 60 days in a recirculation system, maintaining visual contact. After this period, the mirror test was applied. The same procedure was performed with the same individuals after 30 days of visual isolation. Visual isolation did no effect on the aggressive behaviour. Application of oxytocin (2.5 µg/g) for 1 h (twice) in this first stage was also conducted after the mirror test. The effect of exposure to oxytocin was evaluated by applying the mirror test 24 h after the second exposure. The second stage was conducted with another 10 individuals exposed to oxytocin (7.5 µg/g) for 1 h, after which the mirror test was performed. Exposure to oxytocin (2.5 µg/g) did not effect on combat-related behaviours. However, in the second stage influenced all behaviours related to combat and display, with an increase in the frequency of “rest” behaviour. The results indicate that exposure to a neuropeptide at a dose of 7.5 µg/g reduces the frequency of aggressive behaviour of male Betta splendens.

Care and Use of Siamese Fighting Fish (Betta Splendens) for Research.

Betta splendens, also called Siamese fighting fish or 'betta,' are a popular species in the fishkeeping hobby. Native to South- east Asia, betta have been selectively bred for their fighting ability for hundreds of years, which has resulted in the species' characteristic male aggression. More recently, betta have been bred for a number of ornamental traits such as coloration, fin morphology, and body size. Betta have unique characteristics and an evolutionary history that make them a useful model for studies in the fields of behavior, endocrinology, neurobiology, genetics, development, and evolution. However, standard laboratory procedures for raising and keeping these fish are not well established, which has limited their use. Here, we briefly review the past and present use of betta in research, with a focus on their utility in behavioral, neurobiological, and evolutionary studies. We then describe effective husbandry practices for maintaining betta as a research colony.

DAYA PREDASI IKAN PEMAKAN JENTIK NYAMUK Aedes Sp SEBAGAI SUMBER BELAJAR UNTUK MENYUSUN PANDUAN PRAKTIKUM BIOLOGI SMA

Mosquitoes are vectors of various diseases such as malaria, DHF, and elephantiasis. Many attempts have been made to suppress the mosquito population, one of which is biological control using mosquito larvae. The purpose of this study was to determine the predation power of the Aedes sp larvae. This type of research is descriptive. The data obtained are presented in tabular form and analyzed descriptively. The results showed that the predation power of betta fish (Betta splendens) was higher (80 larvae / 24 hours) compared to guppy fish (Poecillia reticullata) with 52 larvae / 24 hours and black molly fish (Poecillia splendens) with 42 larvae / 24 hours. The results of the study were validated by design experts and material experts with a percentage of 71.24% (good criteria) and compiled as a source of learning in the form of biology practical instructions for senior high school. Kata Kunci : Daya Predasi, Jentik nyamuk, sumber belajar biologi

Something Fishy about Siamese Fighting Fish (Betta splendens) Sex: Polygenic Sex Determination or a Newly Emerged Sex-Determining Region?

Fishes provide a unique and intriguing model system for studying the genomic origin and evolutionary mechanisms underlying sex determination and high sex-chromosome turnover. In this study, the mode of sex determination was investigated in Siamese fighting fish, a species of commercial importance. Genome-wide SNP analyses were performed on 75 individuals (40 males and 35 females) across commercial populations to determine candidate sex-specific/sex-linked loci. In total, 73 male-specific loci were identified and mapped to a 5.6 kb region on chromosome 9, suggesting a putative male-determining region (pMDR) containing localized dmrt1 and znrf3 functional sex developmental genes. Repeat annotations of the pMDR revealed an abundance of transposable elements, particularly Ty3/Gypsy and novel repeats. Remarkably, two out of the 73 male-specific loci were located on chromosomes 7 and 19, implying the existence of polygenic sex determination. Besides male-specific loci, five female-specific loci on chromosome 9 were also observed in certain populations, indicating the possibility of a female-determining region and the polygenic nature of sex determination. An alternative explanation is that male-specific loci derived from other chromosomes or female-specific loci in Siamese fighting fish recently emerged as new sex-determining loci during domestication and repeated hybridization.

Detection of Mycobacterium marinum and multidrug-resistant bacteria in a chronic progressive disease outbreak among Siamese fighting fish (Betta splendens) in India

Detection of Mycobacterium marinum and multidrug-resistant bacteria in a chronic progressive disease outbreak among Siamese fighting fish (Betta splendens) in India

Prevalence of ectoparasites in betta fish (Betta splendens R.) in Pekalongan City

ABSTRACT In Pekalongan City, Betta fish, or Siamese fighting fish is gaining popularity. However, many problems often occur in Betta fish care, such as disease attacks from parasites, including ectoparasites. This research identified the types of ectoparasites in Betta fish and determined its prevalence and degree of infection in betta fish in Pekalongan City. In this exploratory research, data were descriptively analyzed. The data were obtained from 60 samples of betta fish measuring 3.5–5.6 cm taken from betta farmers in Pekalongan City. The results of this research revealed that Tetrahymena sp and Ichthyopthirius multifilis had different prevalence levels of 46.66% for that 3.5 – 4.5 cm in length, and 43.33% of fish with 4.6-5.6 cm long, respectively 44,6 % and 40 % for Ichtyoptirius multifilis. The infection value was 6.79/fish for Tetrahymena sp (moderate), and 4.6/fish for Ichthyopthirius multifilis (low). The water quality parameters were; the temperature of 27.1 – 28.90C, DO 5.8 – 8.2 mg/l, and a pH of 6.3 – 7.3.Keywords: Ectoparasite, Betta Fish, Prevalence, Tetrahymena

Variation in nest building, aggression, learning, and steroid hormone levels in Betta splendens

Individuals within a population present behavioral responses that vary according to intrinsic and extrinsic factors such as ontogenetic phase, nutritional status, reproductive stage, and previous experiences. These differences can be explained by endogenous changes, such as hormone release, that can modulate reproductive behaviors, stress response, and cognitive processes. In order to investigate the relationship between behavior and hormonal levels in the fighting fish Betta splendens, the present study characterized nest building, aggressive behavior, learning of a task, and levels of cortisol and 11-ketotestosterone (11-KT) in 86 male Fighting fish. At the beginning of the experiment (days 1–4), fish were characterized as nest builders, intermediate builders, or non-builders. They were then sequentially tested for aggression (days 7–8), learning performance (days 11–21), and circulating hormone levels (day 23). Nest builders showed the lowest hormonal levels at the end of the experiment and low aggressiveness; Intermediate builders presented low cortisol, but high KT levels and best learned the task; Non-builders were the most aggressive animals with higher cortisol levels (at day 23). Our data suggest that in B. splendens, aggressive behavior and learning performance are related to the relative investment in reproduction and variation in circulating levels of corticosteroids and androgens.

Changes in color of betta fish (Betta splendens) by feeding of Artemia salina enriched with Tagetes erecta flower flour

Abstract. Kiswara CA, Budiharjo A, Sari SLA. 2020. Changes in color of betta fish (Betta splendens) by feeding of Artemia salina enriched with Tagetes erecta flower flour. Cell Biol Dev 4: 46-50. Betta fish are attractive due to their varied and vibrant colors and aggressive temperament. Carotenoids are the pigments found in betta fish. They are kept in chromatophores. While fish cannot synthesize carotenoids in their bodies, they can absorb them from their diet and use them as pigments to enhance the color intensity of their bodies. The purpose of this study was to determine the degree of color change and survival of betta fish fed with Artemia salina (Linnaeus, 1758), which has Tagetes erecta L. flower flour as their food. This study used a completely randomized design (CRD) and three treatments with varying compositions of rice flour: T. erecta flower flour, namely, 5:1, 2:1, and 1:1, respectively. Artemia salina fed simply with rice flour was a control. Betta fish require 40 days of care. Color intensity was determined once every ten days using a color scale with a score of 1 (white), 2 (weak red), 3 (medium red), and 4 (dark red) (red). The results indicated that A. salina fed in a 1:1 ratio had the best effect on improving the color brightness of betta fish. All parts of the betta fish's body received a score of 4 in this treatment, including the head, fins, and tail.

The ornamental fighting fish is the next model organism for genetic studies

AbstractThe fighting fish Betta splendens is a freshwater species from Thailand and other Southeast Asian countries. This fish has been domesticated for 1000 years and bred for fighting, various colours, body size and fin types for 600 years. It is one of the most important fish species cultured for the world ornamental fish market. This fish is easy to culture, highly fecund and displays great morphological diversity. Its biology has been studied for over 100 years. Recently, its compact genome and transcriptomes have been sequenced. Genome editing with CRISPR/cas9 has been applied to knock out genes in this fish. Its diverse phenotypes, including colours, colour patterns, fin types, and aggressive behaviour, are complementary to those of other model animals. Therefore, this fish could be the next important model organism for studying phenotypic variation and aggressive behaviour. In this paper, we synthesized knowledge about its aquaculture, biology, genetics, genomic tools, phenotypes and novel insights on phenotypic variation, sex determination and aggression. We hope that the information described in this paper will facilitate genetic studies on phenotypic variations in aquaculture and aggressive behaviour in other species, including humans.

Induksi hormon oodev untuk meningkatkan tingkat kematangan gonad ikan cupang betina (Betta splendens) melalui pakan

Betta fish are freshwater ornamental fish that are very popular and have quite high economic value, but the reproductive process still depends on the spawning season, so an increase in reproductive potential is needed. The experiment was conducted in order to determine the role of each induction Oocite development (Oodev) hormone in the diet to betta fish female final maturation process and morphology gonads. Completely randomized design (CRD) with one factor consisting of 5 treatments and 3 replications. The main factors are Oodev hormone dosage: 0.0 mL.kg-1 fish weigh; 0.5 mL.kg-1 fish; 1.0 mL.kg-1 fish; 1.5 mL.kg-1 fish and 2.0 mL.kg-1 fish. We used 135 female broodstock with initial weight range ± 1-2.15 g tail-1 and at stage II of gonad maturation. Fish were fed three a day at 07.00 am, 12.00 am and 05.00 pm at satiation level during 45 days. During the final maturation, gonad morphology, survival rates and water quality were observed. The results show that Oodev hormone induction could improve final maturation up to 266.66%. This result comparatively higher than 0.0 mL.kg-1 and 0.5 mL.kg-1 fish hormone induction, and produce 100% of mature broodstock. Thus, the Oodev hormone induction at optimal dose of 1.16 mL.kg-1 of fish can improve the induction maturation up to 2-3 times faster maturation frequency on the out of spawning season.Keywords: Female Betta splendens; Feed; Final maturation; Oodev

Induction of Oodev Hormone to increase Gonad Maturity Rate Female Betta Fish (Betta splendens) Through Feed

Betta fish are freshwater ornamental fish that are very popular and have quite high economic value, but the reproductive process still depends on the spawning season, so an increase in reproductive potential is needed. The experiment was conducted in order to determine the role of each induction Oocite development (Oodev) hormone in the diet to betta fish female final maturation process and morphology gonads. Completely randomized design (CRD) with one factor consisting of 5 treatments and 3 replications.The main factors are Oodev hormone dosage: 0.0 mL.kg-1 fish weigh; 0.5 mL.kg-1 fish; 1.0 mL.kg-1 fish; 1.5 mL.kg-1 fish and 2.0 mL.kg-1 fish. We used 135 female broodstock with an initial weight range ± 1-2.15 g.ekor-1 and at stage II of gonad maturation. Fish were fed three a day at 07.00 am, 12.00 am, and 05.00 pm at satiation level during 45 days. During the final maturation, gonad morphology, survival rates, and water quality were observed. The results show that Oodev hormone induction could improve final maturation up to 266.66%. This result is comparatively higher than 0.0 mL.kg-1 and 0.5 mL.kg-1 fish hormone induction and produces 100% of mature broodstock. Thus, the Oodev hormone induction at optimal dose of 1.16 mL.kg-1 of fish can improve the induction maturation up to 2-3 times faster maturation frequency on the out of spawning seasonKeywords:Female Betta splendens; final maturation; Oodev; feed

IMPROVEMENT OF WATER QUALITY AND BREEDING OF SIAMESE FIGHTING FISH (BETTA SPLENDENS REGAN) USING INDIAN ALMOND (TERMINALIA CATAPPA) LEAVES

The Siamese fighting fish (Betta splendens Regan) is considered as one of the most famous aquarium fishes in the world. Despite the dozens of popular articles and increasing scientific investigations on this exciting species, accounts dealing with reproductive behavior are noticeably lacking in quantitative description and are sometimes contradictory. Thus, this study aimed to evaluate the effectiveness of Indian Almond (Terminalia catappa) leaves in the water quality parametersand breeding of B. splendens. A completely randomized design was usedin the study having four treatments with three replications. There were 12 experimental units with these notations in each Treatment: T1 (no leaf), T2 (1 leaf), T3 (2 leaves), and T4 (4 leaves) per aquarium with a dimension of 12 x 12 x 10 inches at 12L water volume and stocked with 24breeders (male &amp; female), respectively. The result showed that the water quality parameters were found within the optimum range in all Treatments. The water pH and dissolved oxygen in T4 obtained the best result compared to other Treatments and had a highly significant difference (P&lt;.001) observed. Furthermore, T4 positively promoted breeders to spawn at a hatching rate (HR) of 0.45%, then T3 with 0.07%. In addition, T3 and T4 obtained 100% survival rate (SR)while T2 and T1 with 83.33% and 66.67% SR. The HR and SR of B. splendens showed no significant differencein all treatments. Moreover, the application of Indian Almond (T. catappa) leaves can improve water quality, encourage breeding, promote spawning, survival, and hatching of Siamese fighting fish.

Attractivity and palatability of different hydrolysed proteins for the ornamental species Betta splendens (Regan, 1910)

The objective of this study was to define attractivity and palatability of juvenile Betta splendens when fed diets containing tilapia meal (TM) and a 5% inclusion of different protein sources: chicken protein hydrolysate (CPH), porcine liver protein hydrolysate (PLH), feather protein hydrolysate (PHP) and porcine mucosa protein hydrolysate (PMH). Five juveniles were utilized with an average weight of 2.92 ± 0.24 g, and an average length of 3.24 ± 0.39 cm. Feeding management was determined via random drawings of both specimens and feed type, with a feeding schedule of four times per day, in which feeding habits were observed regarding the time of capture of the first pellet, number of pellet rejections, number of approaches without pellet capture and number of pellets consumed. The data were submitted to ANOVA, and, subsequently, Duncan's test was performed with a 5% significance. The greatest index of attractivity and palatability was encountered with PLH at 17.14%. The significant effect (p < 0.05) was observed in the feeding behaviour regarding the consumption of pellets. Thus, PLH may be utilized to effectively increase consumption in Betta splendens juveniles as a substitute to tilapia meal and as a means of reducing feed waste in aquariums of this species.

Genomic consequences of domestication of the Siamese fighting fish.

Siamese fighting (betta) fish are among the most popular and morphologically diverse pet fish, but the genetic bases of their domestication and phenotypic diversification are largely unknown. We assembled de novo the genome of a wild Betta splendens and whole-genome sequenced 98 individuals across five closely related species. We find evidence of bidirectional hybridization between domesticated ornamental betta and other wild Betta species. We discover dmrt1 as the main sex determination gene in ornamental betta and that it has lower penetrance in wild B. splendens. Furthermore, we find genes with signatures of recent, strong selection that have large effects on color in specific parts of the body or on the shape of individual fins and that most are unlinked. Our results demonstrate how simple genetic architectures paired with anatomical modularity can lead to vast phenotypic diversity generated during animal domestication and launch betta as a powerful new system for evolutionary genetics.

Intra-specific copy number variation of MHC class II genes in the Siamese fighting fish.

Duplicates of genes for major histocompatibility complex (MHC) molecules can be subjected to selection independently and vary markedly in their evolutionary rates, sequence polymorphism, and functional roles. Therefore, without a thorough understanding of their copy number variation (CNV) in the genome, the MHC-dependent fitness consequences within a species could be misinterpreted. Studying the intra-specific CNV of this highly polymorphic gene, however, has long been hindered by the difficulties in assigning alleles to loci and the lack of high-quality genomic data. Here, using the high-quality genome of the Siamese fighting fish (Betta splendens), a model for mate choice studies, and the whole-genome sequencing (WGS) data of 17 Betta species, we achieved locus-specific amplification of their three classical MHC class II genes - DAB1, DAB2, and DAB3. By performing quantitative PCR and depth-of-coverage analysis using the WGS data, we revealed intra-specific CNV at the DAB3 locus. We identified individuals that had two allelic copies (i.e., heterozygous or homozygous) or one allele (i.e., hemizygous) and individuals without this gene. The CNV was due to the deletion of a 20-kb-long genomic region harboring both the DAA3 and DAB3 genes. We further showed that the three DAB genes were under different modes of selection, which also applies to their corresponding DAA genes that share similar pattern of polymorphism. Our study demonstrates a combined approach to study CNV within a species, which is crucial for the understanding of multigene family evolution and the fitness consequences of CNV.

Selection for winners impacts the endocrine system in the Siamese fighting fish

In southeast Asia, males of the Siamese fighting fish, Betta splendens, have been selected across centuries for winning paired staged fights and previous work has shown that males from fighter strains are more aggressive than wild-types. This strong directional selection for winners is likely to have targeted aggression-related endocrine systems, and a comparison between fighter and wild-type strains can bring into evidence the key hormones implicated in aggression. Here, we compared the plasma levels of the androgen 11-ketotestosterone (KT) and of the corticosteroid cortisol (F) in F2 males of a fighter and a wild-type strain raised under similar laboratory conditions. We show that F was generally lower in fighter as compared with wild-type males, while no overall differences in KT levels were detected between strains. When presented with a mirror-induced aggressive challenge, post-fight levels of F increased but more significantly so in wild-type males, while KT increased in males of both strains. After the challenge, fighter males had higher levels of KT as compared with wild-type males, while the pattern for F was opposite. As compared with animals in social groups, wild-type males placed under social isolation had lower F levels, while KT decreased for fighters.Taken together, this data suggests that while wild-type males responded to aggression with an increase in circulating levels of both androgens and corticosteroids, males selected for winning fights maintained a blunt F response, increasing only KT levels. These data agree with the hypothesis that a combination of high levels of androgens and low levels of corticosteroids is associated with high aggression. Overall, these results seem to indicate that selection for winning had a stronger impact in the hypothalamus-pituitary-interrenal axis than in the hypothalamus-pituitary–gonadal axis in B. splendens.