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This study investigated the relationship between the size, condition, year class, family, and sexual maturity of Atlantic salmon (Salmo salar) using data collected in an aquaculture selective breeding programme. Males that were sexually mature at 2 years of age (maiden spawn) have, on average, greater fork length and condition factor (K) at 1 year of age than their immature counterparts. For every 10‐mm increase in fork length or 0.1 increase in K at 1 year of age, the odds of sexual maturity at 2 years of age increased by 1.48 or 1.22 times, respectively. Females that were sexually mature at 3 years of age (maiden spawn) have, on average, greater fork length and K at 2 years of age than their immature counterparts. For every 10‐mm increase in fork length or 0.1 increase in K at 2 years of age, the odds of sexual maturity at 3 years of age increased by 1.06 or 1.44 times, respectively. The family explained 34.93% of the variation in sexual maturity among 2‐year‐old males that was not attributable to the average effects of fork length and K at 1 year of age and year class. The proportion of variation in sexual maturity among 3‐year‐old females explained by the family could not be investigated. These findings suggest that the onset of sexual maturation in Atlantic salmon is conditional on performance (with respect to energy availability) surpassing a threshold, the magnitude of which can vary between families and is determined by a genetic component. This could support the application of genetic selection to promote or inhibit the onset of sexual maturation in farmed stocks. [ABSTRACT FROM AUTHOR]

Most fish are ectothermic; therefore, their physiology is significantly affected by temperature. Aquaculture fish have limited ability to avoid elevated water temperatures, with impacts increasing as a result of climate change. To date, quantifying gene expression has been proposed to monitor heat stress in salmon liver. This study aimed to establish a faster multiplexed proteomics method to measure the abundance of thermal stress biomarkers in liver of salmon reared at 15°C or 20°C. Moreover, this study aimed to determine the effects that sample pooling, and data normalisation using housekeeping (HK) protein peptides would exert over the statistical significance of these thermal stress markers. A multiple reaction monitoring (MRM) mass spectrometry method, comprised 45 peptides derived from thermal stress markers and 10 peptides from HK proteins, was applied to measure these markers in liver of salmon reared at 15°C or 20°C. When samples were processed individually, 34 peptides were significant between salmon livers at 15°C or 20°C. In pooled samples, this decreased to five significant peptides. Peptides hprt1_HYADDLDR (hypoxanthine phosphoribosyl transferase) and gapdh_VPTPNVSVVDLTVR (glyceraldehyde‐3‐phosphate dehydrogenase) were the most stable and unstable HK protein peptides, respectively. When data was normalised with hprt1_HYADDLDR, 16 peptides were significant in individual samples and 13 in pooled samples. Significant peptides serpinh1a_ADLSNISGK, SerpinH1_TNSILFIGR, ela2_VVGGEDVR and gapdh_VPTPNVSVVDLTVR were common regardless of data strategy. A fast and reliable MRM method was established to validate thermal stress markers in salmon liver, where individual samples yielded better results than pooled samples. Sample pooling was only better when combined with normalisation as it validated twice the number of markers than sample pooling alone. This method could be applied to monitoring stress response in experiments involving feeding additives designed to mitigate thermal stress or in selective breeding programs to help understanding family variance in thermal tolerance. [ABSTRACT FROM AUTHOR]

Dominant mutations in the gene encoding the mRNA splicing factor PRPF31 cause retinitis pigmentosa, a hereditary form of retinal degeneration. Most of these mutations are characterized by DNA changes that lead to premature termination codons. We investigated 6 different PRPF31 mutations, represented by single-base substitutions or microdeletions, in cell lines derived from 9 patients with dominant retinitis pigmentosa. Five of these mutations lead to premature termination codons, and 1 leads to the skipping of exon 2. Allele-specific measurement of PRPF31 transcripts revealed a strong reduction in the expression of mutant alleles. As a consequence, total PRPF31 protein abundance was decreased, and no truncated proteins were detected. Subnuclear localization of the full-length PRPF31 that was present remained unaffected. Blocking nonsense-mediated mRNA decay significantly restored the amount of mutant PRPF31 mRNA but did not restore the synthesis of mutant proteins, even in conjunction with inhibitors of protein degradation pathways. Our results indicate that most PRPF31 mutations ultimately result in null alleles through the activation of surveillance mechanisms that inactivate mutant mRNA and, possibly, proteins. Furthermore, these data provide compelling evidence that the pathogenic effect of PRPF31 mutations is likely due to haploinsufficiency rather than to gain of function., Introduction Retinitis pigmentosa (RP) is a hereditary disease that causes progressive degeneration of the retina and leads in many cases to complete loss of sight. Clinically, RP is characterized by [...]

Natural and traditional diets have been gradually replaced with formulated diets for the Chinese mitten crab Eriocheir sinensis culture, but it is unclear what effects different feeding modes have on digestive physiology and metabolism of E. sinensis. This study investigated the effects of three feeding modes, formulated diets (FD), natural diets (ND, trash fish and freshwater snails) and traditional diets (TD, soybean, wheat, broad bean and corn) on digestive enzyme activity, physiological indices and metabolomics of adult female E. sinensis. The ND had the highest activities of trypsin and lipase in the hepatopancreas, while the highest amylase activity was detected in TD. The highest content of hepatopancreas triglyceride was detected in FD, while the highest levels of lipoprotein lipase, hepatic lipase, lactic acid, malonaldehyde, acid phosphatase and alkaline phosphatase in the hepatopancreas, as well as the total cholesterol, high‐density lipoprotein cholesterol, low‐density lipoprotein cholesterol and γ‐glutamyltransferase in serum were detected in ND. The TD had the highest content of glucose and uric acid in the hepatopancreas as well as the free cholesterol, lactic acid, aspartate aminotransferase and alanine aminotransferase in the serum. The metabolomics showed that most differential metabolites involved in amino acid anabolism in serum and hepatopancreas were significantly up‐regulated in FD. The metabolites involved in energy metabolism and gluconeogenesis in the hepatopancreas were significantly down‐regulated in FD. These results suggested that feeding with formulated diets promotes amino acid synthesis and reduces energy metabolism, which leads to more protein and glucose deposition in tissue. [ABSTRACT FROM AUTHOR]