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The presence of intermuscular bones in fisheries products limits the consumption and commercialization potential of many fish species, including tambaqui (Colossoma macropomum). These bones have caused medical emergencies and are an undesirable characteristic for fish farming because their removal is labor-intensive during fish processing. Despite the difficulty in identifying genes related to the lack of intermuscular bone in diverse species of fish, the discovery of individuals lacking intermuscular bones in a Neotropical freshwater characiform fish has provided a unique opportunity to delve into the genetic mechanisms underlying the pathways of intermuscular bone formation. In this study, we carried out a GWAS among boneless and wt tambaqui populations to identify markers associated with a lack of intermuscular bone. After analyzing 11 416 SNPs in 360 individuals (12 boneless and 348 bony), we report 675 significant (Padj

Sex-specific DNA markers are useful for studying sex- determination mechanisms and establishment of monosex populations. Three widely spaced geographical populations (Liangzi, Poyang and Yuni Lakes in China) of blunt snout bream (Megalobrama amblycephala) were screened with AFLPs to search for sex-linked markers. Female and male pools (10 individuals in each pool) from each population were screened using 64 different primer combinations. A total of 4789 genomic fragments were produced, with a mean frequency of 75 bands per primer pair. Three different primer combinations produced putative sex-associated amplifications and were selected for individual screening in the three populations. However, none showed sex specificity when we converted these three markers into sequence characterized amplified region markers and evaluated all the individuals from the three populations.

Summary The objective of this study was to compare haematological and serum biochemical parameters of cultured and wild specimens of the northern snakehead, Channa argus, to establish baseline values. Thirty sexually immature and disease-free wild fish (37.70 ± 13.68 cm total length, 555.3 ± 449.0 g weight) and 30 cultured fish (36.82 ± 1.72 cm total length, 450.5 ± 58.8 g weight) were examined. In cultured northern snakehead, the average values of alanine aminotransferases (370.1 IU L−1), aspartate amino transferases (1145.3 IU L−1), albumin (15.84 g L−1), direct billuribin (6.15 μmol L−1), urea (1.40 mmol L−1), glucose (21.54 mmol L−1) and cholesterol levels (6.60 mmol L−1) were significantly higher (P 0.05) was found for total protein, globulin, total bilirubin, chromium, sodium, chloride or triglyceride levels between wild and cultured populations. The mean values of the red blood cell (RBC) counts, hematocrit, haemoglobin, and mean corpuscular volume (MCV) were significantly higher (P

Summary In search for an easy, rapid and cost-effective method to determine the ploidy levels of diploid and tetraploid dojo loaches Misgurnus anguillicaudatus distributed naturally in China, direct (karyotyping) and indirect (flow cytometry, erythrocyte nuclear measurements and morphometric analysis) methods were compared. The results revealed that all techniques employed may be successfully used to determine the ploidy levels. It was discovered that karyotyping is cumbersome; flow cytometry is expensive whereas erythrocyte nuclear measurement requires a long time and intensive labour. On the other hand, the morphometric analysis method, especially the measurement of head length (HL), snout length (SL) and depth of caudal peduncle (CPD), is the simplest, with no damage to the fish and can be considered a practical alternative to other techniques. The discriminant function developed from the specimens, D = 7.539(HL/CPD)−2.342(HL/SL)−5.636, categorized an observation as a diploid if the discriminant analysis gave a positive score, while negative scores were categorized as tetraploids.