Search Results (8)

Chinese tongue sole (Cynoglossus semilaevis) is an important marine aquaculture species that exhibits pronounced female-biased sexual size dimorphism, which limits the economic value of male stocks. The F4 generation of genome-edited dmrt1^−/− ZZ males carried a stable 8 bp deletion in dmrt1, developed ovarian lamella-like gonads and were completely sterile, as in vitro fertilization with their gonads produced no viable embryos. From 12 to 15 months post-hatch (mph), their growth rate was significantly higher than that of wild-type males and ultimately comparable to that of females. They weighed 3.2-fold heavier and measured 1.38-fold longer than their 15 mph wild-type male counterparts. Muscle nutritional composition and most texture traits of dmrt1^−/− ZZ males did not differ from wild-type females. However, their fat content was significantly lower than that of wild-type males, while their Omega6 content was significantly higher. Metabolomic analysis identified 1262 metabolites and revealed differential enrichment of pathways related to amino acids, energy, and antioxidant and neuromuscular metabolism, without evidence of detrimental shifts. Overall, dmrt1 editing yields a fast-growing, functionally sterile male line whose flesh quality is similar to that of wild-type tongue sole, supporting its potential use in sex-control breeding in Chinese tongue sole and providing a valuable model for studying sexual size dimorphism. Full article

Harvesting sea urchins from barrens and enhancing their gonads through aquaculture offers a promising way to convert low-value individuals into high-quality seafood. This study evaluated whether red sea urchins (Mesocentrotus franciscanus, RSUs) fed nutrient-enriched seaweeds produced in a land-based integrated multi-trophic aquaculture (IMTA) system could significantly improve gonad size and quality. Two seaweed species, Ulva australis and Devaleraea mollis, were grown in effluent from white seabass (Atractoscion nobilis) tanks and used to feed RSUs over an 8-week period. RSUs readily consumed both seaweeds, with measurable ingestion, fecal output, and absorption efficiency. We hypothesized that RSUs fed IMTA seaweed would exhibit increased gonadosomatic index and improved gonad quality. GSI significantly increased in both groups, from an initial 3.00 ± 0.50% (9.02 ± 1.80 g) to 4.64 ± 0.66% (23.04 ± 10.20 g) in the U. australis group and to 6.35 ± 1.30% (31.20 ± 7.20 g) in the D. mollis group. Gonad quality improved from “D” (unmarketable) to average “B” (high-quality) grade, based on color, firmness, and texture. These results demonstrate that RSUs collected from barrens can be enhanced into premium seafood using nutrient-enriched seaweeds. Integrating RSUs into land-based IMTA systems may increase aquaculture efficiency, reduce waste, and diversify seafood production in a sustainable and economically viable way. Full article

Urogenital cannulation is a traditional method used in aquaculture to achieve sexual differentiation, but it is considered invasive. Ultrasonography is a valuable non-invasive tool for determining sex and gonadal development in fish species like mullet (Mugil liza) and Brazilian sardine (Sardinella brasiliensis) that lack sexual dimorphism. The methodology involves emitting high-frequency sound waves (20 MHz to 20,000 MHz) above the human hearing range. These waves interact with the tissues of the body, producing echoes that are detected by a transducer. The echoes are then processed by computer graphics to generate detailed images of the internal structures of the organism. This allows for the determination of the sex of fish based on the sonographic features of the tissues. For instance, in male fish, hypoechogenic structures reflect fewer sound waves, leading to darker images. Conversely, in female fish, hyperechogenic tissues reflect more sound waves, resulting in lighter images. It is possible to classify the gonadal maturation stage based on differences in image texture. This non-invasive method eliminates the need for specimen dissection. It is especially valuable when the goal is to preserve the spawners’ life and integrity. This review emphasizes the application of this technology in aquaculture, specifically targeting fish from the Clupeidae and Mugilidae families. Full article

Housefly maggot larvae (HML) have been identified as a potential alternative animal diet for the fattening process of the Chinese mitten crab (Eriocheir sinensis). However, the feasibility and potential impacts of HML supplementation require further investigation. The present study evaluated the effects of dietary HML on the growth indices, nutrient compositions, antioxidant activity, and texture profiles of edible tissues of E. sinensis. The results showed that dietary HML supplementation effectively improved the hepatic steatosis index of both genders and sweet amino acid content of edible tissues (except for male gonad) (p < 0.05). Additionally, dietary HML significantly increased the total antioxidant capacity in the gonad and female muscle (p < 0.05). For the textural properties, HML feeding significantly improved the adhesiveness in the male muscle, and the cohesiveness, chewiness, and resilience in the female muscle (p < 0.05). Furthermore, HML feeding significantly decreased the levels of the equivalent umami concentration of the male gonad, male muscle, and hepatopancreas (p < 0.05). Conversely, HML feeding significantly increased the sweetness value in the muscle, hepatopancreas, and female gonad (p < 0.05). Our findings indicate that HML could serve as a viable alternative feed for fattening to improve the edible yield and change the flavor characteristics in E. sinensis. Full article

Bottarga is a traditional Sardinian (Italy) food derived from several treatments of female mullet gonads (Mugil cephalus) that occur in specific humidity (53%) and temperature (25 °C) conditions. In this work, samples from the east (BEC) and west coasts (BWC) of Sardinia were evaluated for microbiological quality, physico-chemical composition, and sensorial features. Chemical analyses show a protein and fat content of about 39% and 18.6%, respectively, without any difference between the two areas. The bottarga also had a concentration of calcium equal to 455 and 413 mg/kg for BWC and BEC, respectively, as well as a sodium concentration of about 0.70% in both samples. The cholesterol found in the samples was 417 and 389 mg/100 g of the edible part of the bottarga from the west and east coasts, respectively. Overall, microbiological evaluation indicates appropriate hygiene and safety conditions. No significant differences were observed between BEC and BWC samples regarding color uniformity and texture attributes (greasiness, adhesiveness, and friability), while the global odor and sea odor were higher for BWC than BEC. Full article

The market value of sea urchin gonads is determined by the specific characteristics associated with gonad size and texture. Formulated feeds can effectively promote the gonad growth of sea urchins but cannot assure essential gonad texture traits. The objective of this study was to investigate the impact of vitamin C (VC) on the gonad growth, texture, collagen content, and the expression of genes involved in the collagen synthesis of sea urchins (Mesocentrotus nudus). Graded amounts of VC (0, 3000 and 6000 mg/kg) were supplemented to make three formulated feeds. Fresh kelp (Saccharina japonica) was used as the control diet. Each diet was randomly distributed to three tanks of M. nudus. The results indicated that the gonadosomatic index (GSI) and texture traits of M. nudus fed C3000 were significantly greater than those fed C0 and C6000. Collagen type I (Col I) in the gonads of M. nudus fed C3000 showed significantly greater areas than those fed C0 and C6000. Consistently, the expression levels of collagen alpha-1 (colp1α) of M. nudus fed C3000 were significantly higher than those fed C0 and C6000. As for the transforming growth factor beta (tgf-β)/Smads pathway, the expression levels of collagen synthesis genes (tgf-β receptor 1 and 2, smad nuclear-interacting protein 1 (snip1) and prolyl 4-hydroxylase subunit beta (p4hβ)) in the C3000 group were significantly greater than those in the C0, C6000 and kelp groups. On the contrary, the expression levels of collagen degradation genes (lysyl oxidase-like 2 (loxl2) and matrix metalloproteinase 14 (mmp14)) in the C3000 group were significantly lower than those in the C0, C6000 and kelp groups. In conclusion, VC at an addition level of 3000 mg/kg significantly increased the gonad texture and collagen contents of M. nudus, which could be accomplished by increasing collagen synthesis and inhibiting collagen degradation through the tgf-β/Smads pathway. These results could contribute to better understanding the beneficial effects of VC addition on the gonad texture quality of M. nudus. Full article

Paracentrotus lividus is a widespread sea urchin species appreciated worldwide for the taste of its fresh gonads. High-pressure processing (HPP) can provide a thermal equivalent to pasteurization, maintaining the organoleptic properties of the raw gonads. This study evaluated HPP technology’s effect at 350 MPa and 500 MPa on microbial inactivation and biochemical characteristics of P. lividus gonads. HPP at 350 MPa resulted in a higher decrease in protein and free amino acids associated with a loss of olfactory, color, and gustatory traits and a visual alteration of the texture. On the other hand, gonad samples stored for 40 days after treatments at 500 MPa showed a good organoleptic profile similar to fresh gonads. Furthermore, only 500 MPa effectively reduced mesophilic bacteria contamination among the two HPP treatments carried out. Total lipids increased during storage; however, the SAFA/PUFA rate was homogeneous during HPP trials ranging from 2.61–3.91 g/100 g. Total protein decreased more than 40% after HPP at 350 MPa, whereas, after 500 MPa, it remained stable for 20 days. The amount of free amino acid constantly decreased during storage after HPP at 350 MPa and remained constant at 500 MPa. HPP can effectively remove the bacterial flora and inactivate enzymes, maintaining the properties of the fresh sea urchin gonads. Full article

Endocrine-disrupting chemicals include natural and synthetic estrogens, such as 17α-ethynilestradiol (EE₂), which can affect reproduction, growth and immunity. Estrogen signalling is mediated by nuclear or membrane estrogen receptors, such as the new G-protein-coupled estrogen receptor 1 (GPER1). The present work studies the effect of EE₂ and G1 (an agonist of GPER1) on body and muscle parameters and growth-related genes of 54 two-year-old seabreams. The fish were fed a diet containing EE₂ (EE₂ group) and G1 (G1 group) for 45 days and then a diet without EE₂ or G1 for 122 days. An untreated control group was also studied. At 45 days, the shortest body length was observed in the G1 group, while 79 and 122 days after the cessation of treatments, the shortest body growth was observed in the EE₂ group. Hypertrophy of white fibers was higher in the EE₂ and G1 groups than it was in the control group, whereas the opposite was the case with respect to hyperplasia. Textural hardness showed a negative correlation with the size of white fibers. At the end of the experiment, all fish analyzed in the EE₂ group showed a predominance of the gonadal ovarian area. In addition, the highest expression of the mafbx gene (upregulated in catabolic signals) and mstn2 (myogenesis negative regulator) was found in EE₂-exposed fish. Full article