Hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂) are an essential species in marine aquaculture. However, they are susceptible to high temperatures, which can reduce disease resistance, slow growth rates, and decrease production efficiency, resulting in significant economic losses. This study aims to investigate the differences in heat tolerance between hybrid grouper and their parental species, tiger grouper (Epinephelus fuscoguttatus) and giant grouper (E. lanceolatus), and to identify heat stress-related signaling pathways and key genes. Through controlled temperature experiments, we measured the physiological and biochemical parameters of serum (ACP, AKP, TG, COR) and liver (HSP70, HSP90, SOD, CAT) in Hulong hybrid grouper and their parents, followed by liver transcriptome analysis of the three grouper species. The results showed that the lethal temperature of tiger grouper is 41°C, and the lethal temperature of Hulong hybrid grouper and giant grouper is 40°C. Significant changes in antioxidant and heat stress-related indicators were observed in the early stages of stress. Comparative analysis of DEGs related to heat tolerance between Hulong hybrid grouper and their parents revealed common DEGs including the hsp family, danaj family, slc family, pnpla2, magot, actalb, and prodh. Among these, the gene expression trends in hybrids were similar to those of their maternal parent and varied between the same or opposite trends compared to those of their paternal parent. These findings suggest that the hybrids inherit heat regulation genes from both parents, with a higher proportion from the maternal parent, which likely explains their intermediate heat tolerance. This research provides insights into the potential relationship between heat tolerance in Hulong hybrid grouper and their parents and identifies key genetic information affecting heat tolerance.

PAGE \* Arabic \* MERGEFORMAT 3In the published article, there was an error in the legend for [Figure 2] as published. [The English name of the fish is wrong]. The corrected legend appears below.[FIGURE2 (A-L) Changes in serum ACP, AKP, COR, and TG activities in the three grouper species under different stress days. T represents the high temperature group (36°C), Z represents the normaltemperature group (28-29°C), and samples were taken on days 1,2,3,7,11,15,30, and 60 of cultivation. EE represents the Hybrid Grouper, EL represents the Giant Grouper, and EF represents the Tiger Grouper.] The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error in the legend for [Figure 3] as published. [The English name of the fish is wrong]. The corrected legend appears below.[FIGURE3 (A-L) Changes in liver SOD, CAT, HSP70, and HSP90 activities in the three grouper species under different stress days. T represents the high temperature group (36°C), Z represents the normal-temperature group (28-29°C), and samples were taken on days 1, 2, 3, 7, 11, 15, 30, and 60 of cultivation.EE represents the Hybrid Grouper, EL represents the Giant Grouper, and EF represents the Tiger Grouper.] The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error in the legend for [Figure 4] as published. [The English name of the fish is wrong]. The corrected legend appears below.[FIGURE4 GO classification of the Hulong hybrid grouper and its parents.]The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error in the legend for [Figure 5] as published. [The English name of the fish is wrong]. The corrected legend appears below.[FIGURE5 KEGG enrichment of common differential genes between progeny and parents. EE represents the Hulong hybrid Grouper, EL represents the Giant Grouper, and EF represents the Tiger Grouper.]The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error. [The English name of the fish is wrong].A correction has been made to [Abstract], [Paragraph 10,13,16,24]. 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The suitable water temperature range of giant" "decreasing with rising temperatures (Lin et al., 2008). Hulong hybrid groupers fed with shrimp diets exhibit high red blood cell" "conditions (De et al., 2019). Hulong hybrid groupers, resulting from" "Hulong hybrid groupers and their parent species, E. lanceolatus and E."PAGE \* Arabic \* MERGEFORMAT 3"of Hulong hybrid groupers, as well as the parental species, which are" "indirectly affecting the production of Hulong hybrid groupers.""Hulong hybrid groupersand their parent species, Epinephelus" "tolerance in Hulong hybrid groupers and their intrinsic connections" "and key genes involved in the heat stress response of Hulong hybrid groupers and their parents, providing valuable insights for future"]"The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error. [The English name of the fish is wrong]. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.In the published article, there was an error. [The English name of the fish is wrong]. The authors apologize for this error and...

Triploid fish sometimes grow faster and larger than diploids, making them valuable in aquaculture. Their underdeveloped gonads redirect energy from reproduction to muscle growth. This study compared embryonic development and antioxidant responses between allotriploid and hybrid diploid grouper (Epinephelus fuscoguttatus ♀ × E. lanceolatus ♂) after cold shock, aiming to support large-scale allotriploid production. The diploid group had a 99.08% fertilization rate and 82.87% hatching rate, while the triploid group had lower rates (95.71% fertilization, 39.63% hatching, 11.52% deformity). Triploids developed later, with higher incidences of abnormalities and mortality, especially in the gastrula and neuro-embryo stages. Triploid larvae exhibited shortened tails, abnormal yolk sacs, and impaired swimming. Flow cytometry showed triploids that had 1.55 times more DNA and larger red blood cells. Triploids had lower midgut trypsin and lipase levels than diploids (p < 0.05) but similar glucose, liver malondialdehyde, and total cholesterol levels (p > 0.05). However, they had higher liver and spleen lactate dehydrogenase, catalase, and alkaline phosphatase, along with lower spleen malondialdehyde and liver superoxide dismutase (p < 0.05). These findings offer insights into reducing mortality in allotriploid grouper aquaculture, aiding large-scale production efforts.

Two rearing systems are used for Plectropomus leopardus: sea-cage culture and the land-based flow-through aquaculture system. Cages approximate natural conditions and yield many high-quality eggs but offer limited control over ovarian development; the land-based system is highly controllable yet ovaries develop slowly and seldom reach full maturity. We compared these systems by analyzing growth–gonad relationships, monthly hormone profiles (GnRH, E2, GnIH), and hypothalamic transcriptomes in 14- and 18-month-old females. Within each system, body weight did not predict gonadal stage and energy allocation was size-independent. In cages, ovaries reached full maturity with normal histology; in tanks, gonads of all sizes remained at stage III, indicating arrested development. Serum GnRH and E2 displayed parallel increases from 12 to 14 months, declined at 16 months and surged at 18 months in both systems, while GnIH fluctuated inversely, suggesting antagonistic control. Transcriptome analysis identified fshr, cyp11a1 and sox17 as key down-regulated genes in tank-reared fish. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment implicated GnRH, oxidative phosphorylation, ribosome and Wnt pathways in ovarian progression. These findings elucidate reproductive constraints under artificial conditions and provide molecular targets for controllable breeding of P. leopardus.