Parabramis pekinensis was treated as research object in order to investigate the correlation between morphological traits and body weight. We measured 9 morphological indexes including total length (X₁), body length (X₂), body height (X₃), head length (X₄), snout length (X₅), eye diameter (X₆), eye distance (X₇), caudal stalk length (X₈) and caudal stalk height (X₉). The principal morphological traits affecting body weight were screened out and the regression equation was established. The regression equation of Y1 (age 1 group) shape character (X) and weight (Y) was Y = − 169.183 + 32.544 × ₃ + 10.263 × ₄ + 15.655 × ₇. The regression equation of Y2 (age 2 group) shape character (X) and weight (Y) was Y = − 694.082 + 7.725 × ₁ + 72.822 × ₃ + 77.023 × ₆, the regression equation of Y3 (age 3 group) shape character (X) and weight (Y) was Y = − 1161.512 + 26.062 × ₁ + 22.319 × ₂- 107.218 × ₅ + 83.901 × ₇. Gene expression was consistent with these conclusions. TOR signaling pathway expression raised in Y1 then width increased. And GH-IGF-1 signaling pathway expression raised in Y2 then the length increased. In conclusion, the paper could prove that P. pekinensis showed a growth trend, which was increasing width first and length later. In some sense, the study not only enriched the basic biological data of P. pekinensis, but also provided waiting morphological traits for selective breeding of P. pekinensis artificial breeding in future.

Excessive feed input led to eutrophication and Cyanobacterial blooms in the culture of giant freshwater prawn (GFP, Macrobrachium rosenbergii). In order to improve the water quality and control the Cyanobacterial blooms, we tried the mixed culture of oriental river prawn (ORP, Macrobrachium nipponense), which can feed on plant and organic debris. In this study, the culture trial began on June 20th and ended on September 10th. The control group (CG) was GFPs monoculture, while the experimental group (EG) cultured GFPs and ORPs. Water samples were collected from the ponds for five times to compare the changes of water environmental factors and phytoplankton communities in CG and EG. Phosphate, nitrite, sulfide, and ammonia nitrogen in CG were significantly higher than those in EG at the end of culture (p < 0.05). In the middle stage of culture, the Margalef index, Pielou index, and Shannon–Wiener index of EG were significantly higher than those of CG (p < 0.05). The biomass and density of phytoplankton in EG were lower than those in CG, and the occurrence of Cyanobacterial blooms in EG was later. The results indicated that ORPs in the mixed culture model effectively transformed and stored part of the energy by consuming the residual bait, which reduced the degree of eutrophication and Cyanobacterial blooms.

White bream Parabramis pekinensis is an omnivorous fish belong to Cyprinidae that is widespread in Asia. In this study, we presented chromosome-level genome assemblies of P. pekinensis by using PacBio HiFi long reads and Hi-C technology. We assembled high-quality genome of 1.03 Gb with scaffold N50 length of 40.04 Mb, and a total of 98.31% of the assembled sequences were anchored to 24 chromosomes. BUSCO analysis revealed that the genome assembly has a high-level completeness of 98.35% gene coverage. A total of 26,542 protein-coding genes were predicted, of which 92.61% were functionally annotated. The phylogenetic analysis indicated that the lineage leading to P. pekinensis was diverged from the lineage to Megalobrama amblycephala approximately 7.6 million years ago. The high-quality genome assembly provide valuable resources for evolutionary study and genetic breeding of genus Parabramis.

Unreasonable ratio of protein to lipid in feeds could affect growth, antioxidant, and related pathway genes expression. This study aimed to investigate the suitable proportion of protein to lipid in feed with Parabramis pekinensis . The ratio protein‐lipid ( P / L) indicated by G1 (2.52), G2 (3.16), G3 (4.03), G4 (5.33), G5 (7.49), and G6 (11.67), which were fed to P. pekinensis (80 ± 10.52 g) for 56 days. The present results showed that diets with a protein‐to‐lipid ratio of approximately 3.5:1 (35% protein and 10% lipid, or less) were optimal for enhancing growth parameters, including body weight, WGR, PER, VSI, HSI, SGR, and feed conversion ratio (FCR). The quadratic regression analysis of FCR and protein efficiency ratio (PER) in P. pekinensis showed that P/L ratio performed best around 5.33. As the P/L ratio in feeds turned down, the best growth performance appeared at about 5.33 ( p < 0.05), which was due to the unbalanced feed protein and fat levels. Meanwhile, P/L in 5.33 group exerted a protective function against oxidative damage in P. pekinensis . In addition, the increased antioxidant capacity contributed to the growth performance of the fish in 5.33 group, which showed the connection obviously. Thus, the connection existed in target of rapamycin (TOR) and Nrf2 signaling pathway, which was downregulated when the P/L ratio was around 2.52 and 11.67. On the contrary, the P/L ratio around 5.33 could enhance the expression of tor and s6k1 to improve the growth of P. pekinensis . In the Nrf2 signaling pathway, the expression of keap1 , sod1 , and gpx affected antioxidant ability and the P/L ratio from 4.03 to 7.49 could be able to balance the antioxidant capacity, maintaining in normal level of P. pekinensis .