Halibut Hb18

In this study, halibut bone, a byproduct of Greenland halibut processing, was prepared into a thick soup through a non-frying process. The formation of colloidal micro-nano particles and flavor characteristics in halibut bone soup was explored. The results showed that the nutrients in halibut bones migrated to the soup continuously with the cooking process and reached the highest concentration (total sugars, 38.16 mg/100 ml; water-soluble proteins, 25.71 mg/ml; fatty acids, 2.15 g/100 ml; solids, 1.14 g/100 ml) at 150 min. Taste substances such as organic acids, 5'-nucleotides and total free amino acids (TFAAs) content in halibut bone soup also reached maximum at 150 min. At this time, results for particle size showed that MNPs with uniform size (725.62 nm) were formed, which made the bone soup milky white, stable, and had good tasting. Headspace-gas chromatography-ion mobility spectrometry results showed that a total of 59 volatile substances were detected from the halibut bone soup. The content of volatile flavor substances in the 150 min group was lower than that in the 90-120 min group. Meanwhile, aldehydes and ketones gradually became esters. PRACTICAL APPLICATION: Soup is an indispensable part of the world food culture. In order to increase the added value of Greenland halibut, halibut bone soup was studied in this paper. This study found that halibut bone soup that had not been fried, formed the MNPs and has a more harmonious and pleasant flavor. Thus, non-fried halibut bone soup is a good processing method and can improve economic efficiency.

Otoliths (ear-stones) in the inner ears of vertebrates containing visible year zones are used extensively to determine fish age. Analysis of otoliths is a time-consuming and difficult task that requires the education of human experts. Human age estimates are inconsistent, as several readings by the same human expert might result in different ages assigned to the same otolith, in addition to an inherent bias between readers. To improve efficiency and resolve inconsistent results in the age reading from otolith images by human experts, an automated procedure based on convolutional neural networks (CNNs), a class of deep learning models suitable for image processing, is investigated. We applied CNNs that perform image regression to estimate the age of Greenland halibut (Reinhardtius hippoglossoides) with good results for individual ages as well as the overall age distribution, with an average CV of about 10% relative to the read ages by experts. In addition, the density distribution of predicted ages resembles the density distribution of the ground truth. By using k*l-fold cross-validation, we test all available samples, and we show that the results are rather sensitive to the choice of test set. Finally, we apply explanation techniques to analyze the decision process of deep learning models. In particular, we produce heatmaps indicating which input features that are the most important in the computation of predicted age.

Atlantic Halibut (Hippoglossus hippoglossus) has a X/Y genetic sex determination system, but the sex determining factor is not known. We produced a high-quality genome assembly from a male and identified parts of chromosome 13 as the Y chromosome due to sequence divergence between sexes and segregation of sex genotypes in pedigrees. Linkage analysis revealed that all chromosomes exhibit heterochiasmy, i.e. male-only and female-only meiotic recombination regions (MRR/FRR). We show that FRR/MRR intervals differ in nucleotide diversity and repeat class content and that this is true also for other Pleuronectidae species. We further show that remnants of a Gypsy-like transposable element insertion on chr13 promotes early male specific expression of gonadal somatic cell derived factor (gsdf). Less than 4.5 MYA, this male-determining element evolved on an autosomal FRR segment featuring pre-existing male meiotic recombination barriers, thereby creating a Y chromosome. Our findings indicate that heterochiasmy may facilitate the evolution of genetic sex determination systems relying on linkage of sexually antagonistic loci to a sex-determining factor.