scholarly journals Aquaculture-Mediated Invasion of the Genetically Improved Farmed Tilapia (Gift) into the Lower Volta Basin of Ghana

Diversity ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 188 ◽  
Author(s):  
Anane-Taabeah ◽  
Frimpong ◽  
Hallerman

The need for improved aquaculture productivity has led to widespread pressure to introduce the Genetically Improved Farmed Tilapia (GIFT) strains of Nile tilapia (Oreochromis niloticus) into Africa. However, the physical and regulatory infrastructures for preventing the escape of farmed stocks into wild populations and ecosystems are generally lacking. This study characterized the genetic background of O. niloticus being farmed in Ghana and assessed the genetic effects of aquaculture on wild populations. We characterized O. niloticus collected in 2017 using mitochondrial and microsatellite DNA markers from 140 farmed individuals sampled from five major aquaculture facilities on the Volta Lake, and from 72 individuals sampled from the wild in the Lower Volta River downstream of the lake and the Black Volta tributary upstream of the lake. Our results revealed that two farms were culturing non-native O. niloticus stocks, which were distinct from the native Akosombo strain. The non-native tilapia stocks were identical to several GIFT strains, some of which showed introgression of mitochondrial DNA from non-native Oreochromis mossambicus. We also found that the non-native cultured tilapias have escaped into the wild and interbred with local populations, and also observed potentially admixed individuals on some farms. Our results highlight aquaculture as a vector in the spread of invasive non-native species and strains, and underscore the importance of genetic baseline studies to guide conservation planning for wild populations.

2011 ◽  
Vol 9 (4) ◽  
pp. 915-919 ◽  
Author(s):  
Valter Monteiro de Azevedo-Santos ◽  
Odila Rigolin-Sá ◽  
Fernando Mayer Pelicice

Cage aquaculture has been developed in many countries, including Brazil. This form of production, although economically productive, may cause several impacts to the environment. Considering the historical relationship between aquaculture and species introduction, our study investigated the potential of cage aquaculture in spreading non-native species into hydroelectric reservoirs. We interviewed 19 fish farmers in Furnas Reservoir, Grande River basin. All producers have grown exclusively Nile tilapia (Oreochromis niloticus), an African fish, and all producers reported the occurrence of fish escapes. Releases were mainly accidental, but highly frequent during some management procedures, such as length classification, fish capture and juvenile stocking. Escapes were also reported due to cage damage and deliberate releases. These results indicate that, in cage aquaculture facilities, fish are frequently released to the external environment. When raising non-native species (e.g. Furnas Reservoir), these facilities constitute an important vector for fish introductions.


2015 ◽  
Vol 1 (1) ◽  
pp. 147-158
Author(s):  
Mohd Golam Quader Khan ◽  
Brendan J McAndrew ◽  
David J Penman

Sex determination in the Nile tilapia Oreochromis niloticus is more complex than a simple XX-XY sex determining mechanism, as evidenced from fairly frequent unexpected sex ratios in progeny. The production of uniform, homozygous experimental material is particularly advantageous for studying sex determining mechanism as well as for the genetic mapping and genome sequencing studies in which interpretations are facilitated by homozygosity. To better understand the genetic mechanism of sex determination, a fully inbred line of clonal females (XX) was verified in controlled environmental conditions using test crosses and microsatellite DNA markers from the tilapia linkage map. A total of successfully amplified 87 microsatellite DNA markers covering all 24 linkage groups were selected for screening sexually mature females from this line. 67 markers were found polymorphic in outbred individuals screened. Markers from LG1, LG3 and LG23 were given more emphasis because sex determining genes have been mapped on these LGs in different species of tilapia. The verification and validation of this clonal line of females made them an important resource to use as a ‘standard reference line’ in genomics, sex determination studies and other studies in Nile tilapia. DOI: http://dx.doi.org/10.3329/ralf.v1i1.22378 Res. Agric., Livest. Fish.1(1): 147-158, Dec 2014


2018 ◽  
Vol 49 (12) ◽  
pp. 3919-3925
Author(s):  
Nur Un Nesa ◽  
Abdullah Al Faroque ◽  
Md. Rafiqul Islam Sarder ◽  
Md. Fazlul Awal Mollah

2018 ◽  
Vol 51 ◽  
pp. 185-192
Author(s):  
S. Kruhlyk ◽  
V. Dzitsiuk ◽  
V. Spyrydonov

Genetic variability of domestic dogs is a source for effective process of breed formation and creating unique gene complexes. In the world, for preservation of genetic resources of dogs, there are dog training associations which have great confidence: American Club Dog Breeders (AKC), the British Kennel Club (KC) and the Federation Cynologique Internationale (FCI), aimed at protecting breeding dogs, standards creation, registration of a breed, and issuance of accurate pedigrees. Evaluation of the genetic diversity of dog breeds is able to significantly complement and improve their breeding programs. Since breeds of dog differ in morphological and economic characteristics, the problem of finding of the breed features in the genome of animals is becoming more topical. From this point of view, French Bulldog is an interesting breed of dog (FRANC.BULLDOGGE, FCI standard number 101) which belongs by the classification of breeds, adopted in FCI, to the group IX – a dog-companion for health and fun, but to a subgroup of fighting dogs of a small format. French Bulldog breed has been researched slightly not only in Ukraine and also abroad, as the main work of all dog association is focused on solving theoretical and practical issues of breeding, keeping, feeding, veterinary protection and others. The study was conducted at Research Department of Molecular Diagnostic Tests of Ukrainian Laboratory of Quality and Safety of Agricultural Products. 33 animals of French Bulldog breed, admitted to use in dog breeding of Ukrainian Kennel Union (UKU), were involved for the genetic analysis using DNA markers. The materials of the research were buccal epithelial cells, selected before the morning feeding of animals by scraping mucous membrane of oral cavity with disposable, dry, sterile cotton swab. Genomic DNA was extracted using KIT-set of reagents for DNA isolation according to the manufacturer's instructions. PEZ1, PEZ3, PEZ6, PEZ8, FHC 2010, FHC 2054 markers, recommended by International Society for Animal Genetics (ISAG), ACN, КC and FCI, were used for research. As a result of research 25 alleles for all the loci were detected in the experimental sample of dogs. The average number of alleles at the locus Na, obtained by direct counting, was 4.16. The most polymorphic loci for this breed were PEZ6 and PEZ3 with 8 and 6 allelic variants. Monomorphic loci were PEZ8 and FHC 2054 which had 4 and 3 alleles and the lowest level of polymorphism was observed for PEZ 1 and FHC 2010 loci in which only 2 alleles were identified. On analyzing the molecular genetic characteristics of dogs of French Bulldog breed, we found a high variability of genotype on rare alleles, which included alleles: M, C, D, E, J, K, L, O, N and representing 60% of the total number of the identified alleles. C, D, E alleles for PEZ3 locus and O allele at PEZ6 locus are unique to the sampling of dogs because they are not repeated in other loci. Typical alleles: N, F, R, I, P, K, M are 40% of the total. But F, R alleles for PEZ3 locus and P allele for locus PEZ6 are not repeated either in standard allelic variants or in rare one, indicating a high information content of these alleles and loci to be used for further monitoring of allele pool, genetic certification and identification of dogs. Microsatellite DNA loci were analyzed as a result of investigations of French Bulldogs and the most informative: PEZ3, PEZ6 and PEZ8 were found, which have high efficiency in individual and breed certification of dogs due to high variability. These data allow further monitoring of the state of genetic diversity of the breed and the development of measures for improvement of breeding to preserve the structure of breeding material. The study of individual and population genetic variability is advisable to continue for breeding of French Bulldogs "in purity" and preserving valuable gene complexes. The results are the basis for further monitoring of the proposed informative panels of microsatellite DNA markers for genotyping dog of French Bulldog breed and their complex evaluation.


2008 ◽  
Vol 16 (2) ◽  
pp. 156
Author(s):  
Liao Xinjun ◽  
Chang Hong ◽  
Zhang Guixiang ◽  
Wang Donglei ◽  
Song Weitao ◽  
...  

2010 ◽  
Vol 34 (2) ◽  
pp. 169-177
Author(s):  
Fu-ping LIU ◽  
Jun-jie BAI ◽  
Hong-mei SONG ◽  
Xing YE ◽  
Sheng-jie LI ◽  
...  

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 460
Author(s):  
Tawni B. Riepe ◽  
Victoria Vincent ◽  
Vicki Milano ◽  
Eric R. Fetherman ◽  
Dana L. Winkelman

Efforts to advance fish health diagnostics have been highlighted in many studies to improve the detection of pathogens in aquaculture facilities and wild fish populations. Typically, the detection of a pathogen has required sacrificing fish; however, many hatcheries have valuable and sometimes irreplaceable broodstocks, and lethal sampling is undesirable. Therefore, the development of non-lethal detection methods is a high priority. The goal of our study was to compare non-lethal sampling methods with standardized lethal kidney tissue sampling that is used to detect Renibacterium salmoninarum infections in salmonids. We collected anal, buccal, and mucus swabs (non-lethal qPCR) and kidney tissue samples (lethal DFAT) from 72 adult brook trout (Salvelinus fontinalis) reared at the Colorado Parks and Wildlife Pitkin Brood Unit and tested each sample to assess R. salmoninarum infections. Standard kidney tissue detected R. salmoninarum 1.59 times more often than mucus swabs, compared to 10.43 and 13.16 times more often than buccal or anal swabs, respectively, indicating mucus swabs were the most effective and may be a useful non-lethal method. Our study highlights the potential of non-lethal mucus swabs to sample for R. salmoninarum and suggests future studies are needed to refine this technique for use in aquaculture facilities and wild populations of inland salmonids.


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