Fish Genetics

DNA analysis of hake products commercialized in southern European (Spanish and Greek) market chains have demonstrated more than 30% mislabeling, on the basis of species substitution. Tails and fillets were more mislabeled than other products, such as slices and whole pieces. African species were substitute species for products labeled as American and European species, and we suggest it is a case of deliberate economically profitable mislabeling because real market prices of European and American hake products are higher than those of African in Spanish market chains. The presented results suggest fraud detection that disadvantages African producers. Government-mandated genetic surveys of commercial hakes and the use of subsequent statements of fair trade on labels of seafood products could help to reduce fraud levels in a global market of increasingly conscious consumers sensitive to ethical issues.

Nile tilapia is a high economically fish species and also as one of the targets in increase production program by the Ministerial of Marine Affairs and Fisheries 2010-2014. One of the obstacles to reach the goal is that the growth of Nile Tilapia decrease when they reach gonad maturation stage and the spawning being uncontrolled, so the productivity becomes suboptimal. Rearing of sterile (triploid, 3N) Nile tilapia is one solution to prevent uncontrolled spawning. In this study to obtain high percentage of triploid Nile tilapia, different age of embryos (i.e. 2, 3, 4, 5 and 6 min after fertilization, maf) were subjected to heat shock treatment of
41±10C for 4 minutes. The results showed that the use of 3-maf old embryos produces 100% triploid and similar hatching rate with the control. The percentage of triploid individuals in other treatments was also high (88-100%), but low hatching rate. Thus, this method can be applied to produce triploid Nile tilapia to support enhancement of aquaculture production level.

The Indonesian leaffish Pristolepis grootii (Bleeker, 1852) is an indigenous fish species. The purpose of this study was to analyze the characteristics of the β-subunit of follicle-stimulating hormone (FSH-β) and the β-subunit of luteinizing hormone (LH-β) of P. grotii. Complementary DNA (cDNA) was synthesized from mRNA that was extracted from P. grootii pituitary glands. Twelve fish were reared in two aquaria and injected with luteinizing hormone-releasing hormone analog (LHRHa) for the analysis of FSH-β and LH-β gene expression. The results showed that P. grootii FSH-β was 227 bp in length, consists of 93 amino acid residues, while LH-β was 300 bp in length and consists of 100 amino acid residues. P. grootii FSH revealed the highest similarity (91%) with climbing perch Anabas testudineus, while LH-β with Betta splendens (90%). Two putative N-glycosylation sites in FSH-β and one site in LH-β were conserved in P. grootii. The expression of FSH-β and LH-β in fish injected with LHRHa was higher than that of LHRHa not injected fish. The ovary of P. grootii had various sizes of oocytes. The injection of LHRHa affected the development of oocytes; there was a trend for higher doses LHRHa to develop oocytes faster. Thus, it is most likely that the isolated genes are FSH-β and LH-β of P. grootii.

In order to put cultured species on the market with high quality and few casualties, many important studies are carried out. Most of the researches are conducted in the development of feed and feed ingredients 30-60% of the production cost in farming. Therefore, in aquaculture, an interest in alternative feed ingredients is moving at a very fast rate. In this context, the use of enzymes, probiotics and prebiotics in animal feed has steadily increased in recent years with reasons such as effective control of fish diseases and prevention of infection, strengthening the immune system of fish, increase of the digestibility, reduction of the feed cost, reduction of larval-term mortality, provision of increase in growth, live weight gain, and getting rid of the negative effects of stress.

A study on the food and feeding habit of Chrysichthys nigrodigitatus (Lacepede) was conducted in River Niger within the
region of Oshimili local government area of Delta State Nigeria. A total of 90 specimens were collected with the help of fishermen
using gill net, cast net and traps. The fish samples were immediately taken to the laboratory for analysis. Morphometric characteristics
such as weight, length, condition factor, egg weight, Gonado Somatic Index (GSI) and sex ratio were determined. The stomach content
was analyzed using numerical method to determine the food content. The total length of the fish sampled ranged from 14.40-44.60 cm,
while the standard length varied from 11.00 cm to 47.00 cm and the fish body weight ranged between 19.00 g to 503.20 g. Sex ratio 1
female to 1 male was observed. The mean condition factor for both male and female obtained was 1.67. Of all the 90 fishes sampled,
none had empty gut representing 100%. The major food items were phytoplankton, plant part and Detritus. Out of 41 females sampled,
only 17 had eggs and the eggs were matured at stage IV.

Tujuan dari penelitian ini adalah mengetahui dosis hormon 17α-metiltestoteron yang optimal untuk pembentukan kelamin jantan ikan lele sangkuriang (Clarias sp). Metode penelitian eksperimental menggunakan Rancangan Acak Lengkap (RAL) dengan 4 perlakuan dan 3 ulangan. Pada benih lele sangkuriang yang berumur 20 hari direndam dengan hormon 17α-metiltestoteron dengan dosis 0, 4, 6 dan 8 mg/l air selama 8 jam. Wadah penelitian adalah stoples dengan volume 15 liter air sebanyak 12 unit yang dilengkapi dengan heater dan aerasi. Jumlah benih yang direndam sebanyak 30 ekor per perlakuan. Hasil penelitian menunjukkan bahwa P3 (dosis 8 mg/l) mendapatkan persentase jantan tertinggi yaitu sebesar 71,11% dan uji statistik menunjukkan perbedaan yang nyata (Fhitung > Ftabel 0,05), kelangsungan hidup tertinggi pada P0 (kontrol) yaitu sebesar 82,22%, uji statistik menunnjukkan perbedaan yang sangat nyata (Fhitung > Ftabel 0,01) dan pertumbuhan bobot harian tertinggi pada P0 (kontrol) yaitu sebesar 1,928%, uji statistik juga menunjukkan perbedaan yang nyata (Fhitung > Ftabel 0,05).

Batak fish (Tor soro) is a fish species found in North Sumatra that have a high economic value. Information of chromosome is required as early stage genetic characterization of soro. This activity aims to determine the number of chromosomes soro. Solid tissue chromosome preparation procedure involves dipping of fish in Colchicine solution, hypotonic treatment, fixation with Carnoy solution, ring-making, and staining using 10% Giemsa solution. The result of thisstudy was the number of chromosomes soro is 100 chromosomes (2n).

Context: DNA fingerprinting using genetic markers such as Random Amplification of Polymorphic DNA (RAPD), Restriction Fragment Length Polymorphism (RFLP), microsatellite (Simple sequence repeat), Amplified Fragment Length Polymorphism (AFLP) etc. can be successfully used to reveal genetic variation within and among different populations. Objective: The aim of the present study was to assess genetic diversity in two wild and one hatchery populations of stinging catfish Heteropneustes fossilis by RAPD fingerprinting. Materials and Methods: A total of 90 live fish (H. fossilis), 30 from each source, were collected from a beel in Patuakhali, a beel in Jessore and Rupali Hatchery, Mymensingh. Genomic DNA was extracted from fin tissues. The concentration of DNA was estimated using a spectrophotometer. Fifteen decamer primers of random sequence from three kits (six from kit A, seven from kit B and two from kit C) (Operon technologies, Inc., Alameda, CA, USA) were screened on sub-samples of...

The early developmental pattern of inland fishes of Bangladesh are not well studied though it has a great importance in fisheries and aquaculture sector. The embryonic study provides interesting information on further growth and health of the fish and considered as an essential component for optimization of fish seed production by natural and induced breeding. Therefore, the current review work has been undertaken to provide a detail information on embryonic development of important inland fishes of Bangladesh. Information was collected from published scientific papers, un-published Masters and PhD dissertations from universities, popular articles and other published and grey literature. Diameters of unfertilized egg of the reviewed fish species were found to be 0.5 to 1.3 mm and fertilized egg were 0.49 to 1.6 mm. Shapes of the egg were also variable from species to species. There is little information available on egg activation and egg micropyle of fish species of Bangladesh. The...

Hatchery production of common carp seed has been practiced for several decades in Bangladesh but information on sperm biology of induced broods is limited. The study aimed to determine the sperm biology artificially induced broods to improve the current hatchery management. Sperm volume, motility, concentration and pH were 2.04±1.07 µl g-1 of fish, 93±3 %, 1.77±0.49×10 10 cells ml-1 and 7.59±0.29, respectively. There has been a substantial variation (p<0.05) in volume (µl g-1 of fish), concentration (×10 10 cells ml-1) and motility (%) among the fortnightly collected sperm samples. The motility (%) of the fresh sperm was similar in all the activation media tested, however, sperm were motile for longer duration in 0.3% than in 0.2% NaCl, tap water and distilled water. Sperm biology of the induced broods would be useful in breeding programs advancing the development of aquaculture of the species.

DNA fingerprinting using genetic markers such as Random Amplification of Polymorphic DNA (RAPD), Restriction Fragment Length Polymorphism (RFLP), microsatellite (Simple sequence repeat), Amplified Fragment Length Polymorphism (AFLP) etc. can be successfully used to reveal genetic variation within and among different populations.

By accident, the world-famous brewery Carlsberg became a central force in global marine science during the first three decades of the 20th century. Within a core group of scientists and managers, Johannes Schmidt (1877-1933) was the key figure combining the efforts of the International Council for the Exploration of the Sea (ICES), the Danish state and several private companies. Launching 26 oceangoing expeditions Schmidt made landmark discoveries such as the breeding ground for the Atlantic eel in the Sargasso Sea. The scientific frontier was pushed literally kilometres into the deep sea and across the World’s oceans. While the formal North Atlantic Empire of the small state of Denmark was in decline, an informal empire of science was erected instead.

Abstract The culture of tetraploid Clarias gariepinus using warm shock entails the production of a species with four set of chromosome per cells. Spawning was carried out, after fertilization (30 min) egg was subjected to warm shock at 38 to 400c for 5 min. A diploid control was produced and its growth and survival rate compared. Tetraploid has the highest mean weight (0.677 ± 0.010), mean length (5.00cm ± 0.577) and survivability of 42.7%. While the diploid has mean length of (5.000 ± 0.012), mean weight of (0.6590 ± 0.010) and 85.3%. Tetraploid has a dual purpose as broodstock in interploidy of triploid and faster growth rate. Key words: Tetraploid, chromosome spawning survivability

Supplying food to billions of people and providing income for many millions more, aquaculture is the fastest growing area of animal-derived food production in the world. Aquaculture is the farming of fish and other animals living in water. The aquaculture industry is currently faced with solving the simultaneous problems of developing economically viable production systems, reducing the impact on the environment and improving public perception. This paper considered aquaculture as the only way to increase fish production and also discusses technical environmental and management considerations regarding the use of genetically modified organism (e.g. fish) in aquaculture. This paper discusses advantage of biotechnological research application and commercialization. Fish farmers, and the researchers who assist themselves with implementing biotechnology tools, are testing various ways of improving production. Transgenic techniques using biotechnology creates fishes with high disease resistance, environmental tolerance, reproductive efficiency and nutritional value. Gene transfer technology is one area where great advances have been made.  Triploidy is a technique for producing sterile fish. Many commercial trout and carp farmers around the world have adopted the use of triploidy and research is underway to optimize its use in salmon. While nature is feeling the increasing pressure of seven billion hungry people, aquaculture provides a sensible alternative to harvesting the rivers and oceans. When holding hands with biotechnology, it has huge potential for becoming the main protein producer of the future. Perhaps even in the near future, when you dip your sushi roll into the soy sauce, delight in the knowledge that what is about to tickle your palate is probably a triploid, genetically superior, sustainably farmed GMO (Genetically Modified Organism) - the product of biotechnology in aquaculture.

Clarias gariepinus growth hormone (CgGH) transgenesis was previously used to develop a population of second-generation (G2) transgenic mutiara catfish (C. gariepinus). The third generation of these fish (1-month old fingerlings) had 2–3 times improvement in growth compared to non-transgenic fish in the commercial feed test for 6 weeks of rearing. We assessed the impact of CgGH transgene expression on growth and protein and amino acid content of the G3 generation of these transgenic mutiara catfish relative to non-transgenic catfish. Since variation in composition of feed mixes can affect protein and amino acid content of fish, we tested three mixtures of commercial feed and boiled tuna (Euthynnus affinis): feed A (50:50 feed to tuna), B (65:35), and C (80:20) to transgenic catfish. Feed A* (50:50) was fed as a control to non-transgenic catfish. Feed efficiency, including feed conversion ratio and protein use efficiency (i.e., protein retention and protein productive value), was asse...

Nile tilapia is a high economically fish species and also as one of the targets in increase production program by the Ministerial of Marine Affairs and Fisheries 2010-2014. One of the obstacles to reach the goal is that the growth of Nile tilapia decrease when they ...

Clarias gariepinus growth hormone (CgGH) transgenesis was previously used to develop a population of second-generation (G 2) transgenic mutiara catfish (C. gariepinus). The third generation of these fish (1-month old fingerlings) had 2-3 times improvement in growth compared to non-transgenic fish in the commercial feed test for 6 weeks of rearing. We assessed the impact of CgGH transgene expression on growth and protein and amino acid content of the G 3 generation of these transgenic mutiara catfish relative to non-transgenic catfish. Since variation in composition of feed mixes can affect protein and amino acid content of fish, we tested three mixtures of commercial feed and boiled tuna (Euthynnus affinis): feed A (50:50 feed to tuna), B (65:35), and C (80:20) to transgenic catfish. Feed A* (50:50) was fed as a control to non-transgenic catfish. Feed efficiency, including feed conversion ratio and protein use efficiency (i.e., protein retention and protein productive value), was assessed. Feed efficiency, protein content, and essential amino acid content in G 3 transgenic catfish (feed A and B) were higher than in non-transgenic fish (feed A*). The latter were deficient in lysine and methionine. Transgenic catfish fed with feed C (80:20) showed lysine deficiency and lower growth than fish fed feeds A and B. Feed B (65:35) was the optimal feed mixture utilized; it increased growth, protein levels, and feed conversion efficiency in G 3 catfish. The growth of transgenic fish was higher than non-transgenic fish when supported by feeding with balanced nutrients.

The founder stock of a captive breeding program is prone to changes in genetic structure due to inbreeding and genetic drift. Genetic characterization of the founder population using suitable molecular markers may help monitor periodic changes in the genetic structure in future. To develop benchmark information about the genetic structure we analyzed six microsatellite loci in the Brodbank collections of rohu (Labeo rohita) originated from three major rivers—the Jamuna, the Padma and the Halda. A total of 28 alleles were detected in 90 individuals with an average of 4.6 alleles per locus. The average observed heterozygosity ranged from 0.655 to 0.705 and the expected heterozygosity ranged from 0.702 to 0.725. The mean FIS values were 0.103, 0.106 and 0.018 for the Jamuna, Padma and Halda fishes respectively. The population pair-wise FST values ranged from 0.0057 to 0.0278. Structure analysis grouped the fishes of the three rivers into two clusters. The numbers of half-sib families were 5, 5 and 4 and the numbers of full-sib families were 12, 10 and 18 for the Halda, Jamuna and the Padma samples respectively. Bottleneck was detected in all the river samples. We recommend to collect more fish from different locations of the major rivers to broaden the genetic variability of the founder stocks of the Brood bank. Keywords: Microsatellite, Genetic variation, Major carps, Brood bank, Bottleneck, Sib-ship