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Fast and versatile beam forming and steering technologies are now crucial for various emerging applications, including wireless optical communications and optical switches. However, these technologies often rely on expensive components, such as spatial light modulators (SLMs) and optical phase arrays (OPAs), which come with complex and power-consuming control systems. In response to this challenge, we propose a dynamic beam-switching method inspired by the mode-hopping effect of lasers. As a proof of concept, we introduce the dynamic beam switching metasurface (DBSM) design, featuring an in-plane mechanical actuation system. Our numerical analyses, based on the finite element method (FEM), demonstrate that the proposed DBSM exhibits versatile beam forming and steering functionalities. These include beam splitting and omnidirectional beam steering. Moreover, we anticipate that the tuning speed of the DBSM will reach the kilohertz (kHz) range or even higher when utilizing a microelectromechanical systems (MEMS) actuator, building upon pioneering research in this field. We envision it holds promising applications in areas such as light detection and ranging (LiDAR), optical wireless communication devices, and optical switches.

A new species of Confuciusornis, a genus of basal birds from the Early Cretaceous, reveals that these early birds had stronger flight capability and more diverse flight modes than previously expected.

The morphology of the pectoral girdle, the skeletal structure connecting the wing to the body, is a key determinant of flight capability, but in some respects is poorly known among stem birds. Here, the pectoral girdles of the Early Cretaceous birds Sapeornis and Piscivorenantiornis are reconstructed for the first time based on computed tomography and three-dimensional visualization, revealing key morphological details that are important for our understanding of early-flight evolution. Sapeornis exhibits a double articulation system (widely present in non-enantiornithine pennaraptoran theropods including crown birds), which involves, alongside the main scapula-coracoid joint, a small subsidiary joint, though variation exists with respect to the shape and size of the main and subsidiary articular contacts in non-enantiornithine pennaraptorans. This double articulation system contrasts with Piscivorenantiornis in which a spatially restricted scapula-coracoid joint is formed by a single set of opposing articular surfaces, a feature also present in other members of Enantiornithines, a major clade of stem birds known only from the Cretaceous. The unique single articulation system may reflect correspondingly unique flight behavior in enantiornithine birds, but this hypothesis requires further investigation from a functional perspective. Our renderings indicate that both Sapeornis and Piscivorenantiornis had a partially closed triosseal canal (a passage for muscle tendon that plays a key role in raising the wing), and our study suggests that this type of triosseal canal occurred in all known non-euornithine birds except Archaeopteryx, representing a transitional stage in flight apparatus evolution before the appearance of a fully closed bony triosseal canal as in modern birds. Our study reveals additional lineage-specific variations in pectoral girdle anatomy, as well as significant modification of the pectoral girdle along the line to crown birds. These modifications produced diverse pectoral girdle morphologies among Mesozoic birds, which allowed a commensurate range of capability levels and styles to emerge during the early evolution of flight.

A number of paravian dinosaurs have been described from the Jurassic Yanliao biota, but these have tended to be morphologically similar to Archaeopteryx. Here, Hu. describe the new paravian dinosaur, Caihong juji gen. et sp. nov., which possesses a suite of unusual skeletal and feather characteristics.

Troodontids were theropod dinosaurs closely related to birds. Here, Xu and colleagues describe a new, feathered troodontid species,Jianianhualong tengi, dating from the Lower Cretaceous period in China that provides insight into troodontid mosaic evolution and paravian feathering.

A new ankylosaurid, Chuanqilong chaoyangensis gen. et sp. nov., is described here based on a nearly complete skeleton from the Lower Cretaceous Jiufotang Formation of Baishizui Village, Lingyuan City, Liaoning Province, China. Chuanqilong chaoyangensis can be diagnosed on the basis of two autapomorphies (glenoid fossa for quadrate at same level as the dentary tooth row; distally tapering ischium with constricted midshaft) and also a unique combination of character states (slender, wedge-like lacrimal; long retroarticular process; humerus with strongly expanded proximal end; ratio of humerus to femur length = 0.88). Although a phylogenetic analysis places Chuanqilong chaoyangensis as the sister taxon of the sympatric Liaoningosaurus near the base of the Ankylosauridae, the two taxa can be distinguished on the basis of many features, such as tooth morphology and ischial shape, which are not ontogeny-related. Chuanqilong chaoyangensis represents the fourth ankylosaurid species reported from the Cretaceous of Liaoning, China, suggesting a relatively high diversity in Cretaceous Liaoning.

Archaeopteryx is the oldest and most primitive known bird (Avialae). It is believed that the growth and energetic physiology of basalmost birds such as Archaeopteryx were inherited in their entirety from non-avialan dinosaurs. This hypothesis predicts that the long bones in these birds formed using rapidly growing, well-vascularized woven tissue typical of non-avialan dinosaurs.We report that Archaeopteryx long bones are composed of nearly avascular parallel-fibered bone. This is among the slowest growing osseous tissues and is common in ectothermic reptiles. These findings dispute the hypothesis that non-avialan dinosaur growth and physiology were inherited in totality by the first birds. Examining these findings in a phylogenetic context required intensive sampling of outgroup dinosaurs and basalmost birds. Our results demonstrate the presence of a scale-dependent maniraptoran histological continuum that Archaeopteryx and other basalmost birds follow. Growth analysis for Archaeopteryx suggests that these animals showed exponential growth rates like non-avialan dinosaurs, three times slower than living precocial birds, but still within the lowermost range for all endothermic vertebrates.The unexpected histology of Archaeopteryx and other basalmost birds is actually consistent with retention of the phylogenetically earlier paravian dinosaur condition when size is considered. The first birds were simply feathered dinosaurs with respect to growth and energetic physiology. The evolution of the novel pattern in modern forms occurred later in the group's history.

An 8-week culture experiment was conducted to evaluate the effects of methionine (Met) on growth, immunity and antioxidant capacity in largemouth bass (Micropterus salmoides). Six dietary Met levels were tested and formulated based on isonitrogenous and isoenergetic principles: 0.74 %, 0.91 %, 1.13 %, 1.37 %, 1.59 % and 1.75 %. Compared to the control group (0 % Met supplementation, diet level of 0.74 %), dietary Met supplementation significantly improved growth, as indicated by higher FW, WG, SGR and lower FCR (p< 0.05). Furthermore, liver Oil Red O staining revealed a significantly lower positive area for groups receiving 1.13–1.75 % Met (p< 0.05). Plasma TC and TG were also significantly lower in the 0.91 %-1.75 % dietary Met groups (p< 0.05). Met supplementation enhanced antioxidant capacity by increasing plasma levels of antioxidant parameters, including CAT, T-SOD and GSH, and by modulating antioxidant gene expression within the Nrf2 signalling pathway in the liver (nrf2, keap1, cat and sod) (p< 0.05), which was supported by significantly lower MDA level in plasma (p< 0.05). Met supplementation also alleviated apoptosis and endoplasmic reticulum stress (ERS) by upregulating anti-apoptotic genes (bcl-2, bcl-xl) and downregulating pro-apoptotic and ERS marker genes (caspase 3, bax, caspase 8, atf4, caspase 9, ask1, ire1, chopα, eif2α, perk) (p< 0.05). Met supplementation also reduced inflammatory responses by modulating NF-κB signalling pathway gene expressions (il-8, nf-κb, il-10 and tnf-α) and lowering plasma TNF-α and IL-8 levels. Nonetheless, mRNA levels of il-1β and tgf-β in the liver and plasma remained unchanged across different Met levels. Based on FCR and SGR, the optimal Met requirement for largemouth bass was determined to be 1.26 %-1.32 % (2.65 %-2.78 % of dietary protein) through quadratic regression analysis. Hence, Met plays a crucial role in regulating growth, immunity, antioxidant, ERS and apoptosis in largemouth bass.

This experiment was aimed to screen the key factors regulating pigment cells and elucidate the potential mechanism of yellowing body color in the channel catfish. Three-channel catfish with all-black body color (NS group) and three channel catfish with yellow body color (YS group) were taken for transcript sequencing analysis using Illumina sequencing technology. The results showed that a total of 2368 significant differentially expressed genes (DEGs) were screened. Compared with the transcription expression genes in the NS group, there were 1003 up-regulated genes and 1365 down-regulated genes in the YS group. Seven DEGs related to pigment regulation were selected for qRT-PCR analysis, and the results confirmed that the transcriptome analysis was reliable. Furthermore, the DEGs were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and the results showed that most of the DEGs were involved in immune response, endocytosis, cell adhesion molecules, etc. Furthermore, analysis of Melanogenesis and Wnt signaling pathways and other pathways with links to pigment regulation obtained by KEGG enrichment revealed that genes that promote melanogenesis, such as etb, plc, and camk2 were significantly down-regulated. Nevertheless, genes that inhibit melanogenesis (nf-κb, tnf-α, ifn) and genes that promote yellow pigmentation (xdh) were significantly up-regulated. In summary, it is hypothesized that oxidative stress is an important factor contributing to the yellowing of the body color of channel catfish, thus causing the expression of genes related to melanogenesis (etb, plc, camk2), yellow pigmentation (xdh), and immune-antioxidant responses (nf-κb, tnf-α, ifn).

The aim of this study was to investigate the effects of dietary yeast polysaccharide (YPS) supplementation on the growth performance, whole-body composition, antioxidant capacity, and immunity of juvenile largemouth bass (Micropterus salmoides). In this study, five diets with YPS levels of 0.00% (control), 0.05% (0.05Y), 0.10% (0.10Y), 0.15% (0.15Y), and 0.20% (0.20Y) were designed and prepared. A total of 300 healthy fish (3.20 ± 0.03 g) were randomly divided into 15 floating cages (1 × 1 × 1 m) in five different groups, with three replicates per group, for an 8-week culture experiment. The 0.10Y and 0.20Y groups had significantly higher feed conversion ratios compared with the control group. There was no significant effect on any of the other growth indicators. Plasma biochemical indices showed that the 0.10Y group exhibited the highest plasma alkaline phosphatase content and the 0.20Y group exhibited the highest plasma glucose content. Plasma antioxidant indices (total antioxidant capacity, superoxide dismutase, and glutathione) and antioxidant genes (catalase and superoxide dismutase) were elevated in the 0.05Y or 0.10Y groups, and the malondialdehyde content decreased with increasing YPS concentration. Moreover, the 0.05Y group showed significantly higher immune-related gene (nuclear factor-kappa B, interleukin-8, and interleukin-10) mRNA expression. Altogether, our results indicate that dietary YPS supplementation enhances the antioxidant and immune capacity of M. salmoides, but with no positive effect on their growth.

This experiment aimed to investigate the effect of dietary supplementation of γ-aminobutyric acid (GABA) on the growth performance, immune response, and oxygen-transport-related factors of Gibel carp (Carassius auratus gibelio). An eight-week culturing experiment was designed with five experimental diets, with the actual GABA content being 368 mg/kg (G1, control group), 449 mg/kg (G2), 527 mg/kg (G3), 602 mg/kg (G4), and 675 mg/kg (G5). The results showed that the level of 527 mg/kg (G3) of GABA significantly increased the specific growth rate (SGR), weight gain rate (WGR), and final body weight (FBW) of Gibel carp, while the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and glucose (GLU) were also increased significantly. In addition, 527 mg/kg (G3) and 602 mg/kg (G4) of GABA significantly increased the total antioxidant capacity (T-AOC). The mRNA expression of tnf-α, tgf-β, and il-10 was significantly increased at the level of 449 mg/kg (G2). In terms of oxygen-carrying capacity, the mRNA expression of epo, tf, tfr1, ho-1, and vegf was markedly increased at the level of 449 mg/kg (G2). In conclusion, dietary GABA supplementation can boost growth performance, enhance the immune system, and increase oxygen-carrying capacity in Gibel carp.

A seven-week trial was designed to evaluate the effects of dietary seaweed polysaccharide (SP) supplementation on the growth performance and physiological health of largemouth bass. The results reveal that the 0.05SP group showed the best growth performance. The mRNA expression levels of tor, 4ebp1, and igf1 genes were remarkably down-regulated in the 0.15SP and 0.2SP groups compared to the control group. The CAT activities were significantly increased in the 0.05SP and 0.1SP groups, and the GSH-Px activity was increased in the 0.15SP group. The expression of the immune response-related gene nfκb was significantly down-regulated in the 0.1SP group, and those of tnfα and il-8 were at the maximum in the control group. Moreover, the expression of il-10 in the 0.15SP and 0.2SP groups was significantly down-regulated. Furthermore, endoplasmic reticulum stress (ERS)-related expression of atf6 was the highest in the control group. Furthermore, the chopα and bax expression levels in the 0.15SP and 0.2SP groups were significantly down-regulated compared with other groups. In addition, the highest expression level of bcl-xl was observed in the 0.15SP group. Finally, the quadratic regression analysis of antioxidant, immune, and ERS core parameters (CAT, nf-κb, and bcl-xl) determined 0.06–0.11% to be the optimal SP supplemental level in largemouth bass diets.

Anchiornis huxleyi has been recently described, based on an incomplete specimen, as a basal avialan filling the morphological gap between non-avian and avian dinosaurs (3). A nearly complete, extensively feathered [...], The early evolution of the major groups of derived non-avialan theropods is still not well understood, mainly because of their poor fossil record in the Jurassic. A well-known result of this problem is the 'temporal paradox' argument that is sometimes made against the theropod hypothesis of avian origins (1). Here we report on an exceptionally well-preserved small theropod specimen collected from the earliest Late Jurassic Tiaojishan Formation of western Liaoning, China (2). The specimen is referable to the Troodontidae, which are among the theropods most closely related to birds. This new find refutes the 'temporal paradox' (1) and provides significant information on the temporal framework of theropod divergence. Furthermore, the extensive feathering of this specimen, particularly the attachment of long pennaceous feathers to the pes, sheds new light on the early evolution of feathers and demonstrates the complex distribution of skeletal and integumentary features close to the dinosaur-bird transition.

An eight-week trial was designed to study the effects of arginine (Arg) supplemented diets on the growth, immunity, antioxidant activity, and oxygen-carrying capacity of juvenile Gibel carp (Carassius auratus gibelio). A total of 300 fish (27.53 ± 0.03 g) were randomized into 15 equal groups and fed on diets with graded Arg levels: 0 (control), 0.2%, 0.4%, 0.6%, and 0.8% (w/w). The results showed that final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) all increased and then declined with increasing levels of Arg supplementation, while feed conversion ratio (FCR) showed the opposite trend. In addition, the fish’s whole-body crude protein and ash content had no remarkable difference at different levels of Arg addition (p > 0.05). Supplementation with 0.6% and 0.8% Arg significantly increased plasma alanine transaminase (ALT) activity (p < 0.05). The malondialdehyde (MDA) levels and superoxide dismutase (SOD) activities of the liver were not significantly different between the different levels of Arg supplementation (p > 0.05), while catalase (CAT) activity was significantly increased with 0.4% Arg supplementation levels (p < 0.05). The 0.8% Arg supplementation greatly increased the expression of hepatic-related genes to the Nrf2 signaling pathway, including sod and gpx (p < 0.05). However, the 0.8% Arg supplementation did not significantly increase the relative expression of genes related to the NF-κB signaling pathway, including il-1β, il-8, and tnf-α (p > 0.05). Similarly, the relative expression of hif-1 signaling pathway-related genes at 0.8% Arg supplementation was significantly elevated, including hif-1α, epo, and vegf (p < 0.05). Hence, Arg supplementation could promote growth and improve immune, antioxidant, and oxygen-carrying capacity in juvenile Gibel carp.

As a restricted amino acid, threonine (Thr) deficiency reduces antioxidant and immune capacity in fish. In the present study, six diets containing different Thr levels (1.39 %, 1.71 %, 1.95 %, 2.28 %, 2.58 %, and 2.65 %) were fed to largemouth bass (15±0.1 g) for 60 days. The present results showed that neither growth nor whole-body composition was affected by different Thr levels. And low dietary Thr levels (1.39 %) significantly decreased serum total protein (TP) and albumin (ALB) levels, but increased alkaline phosphatase (ALP) levels. And 1.39 % Thr diet significantly decreased liver catalase (CAT) activity but increased malonaldehyde (MDA) levels, and the maximum total antioxidant capacity (T-AOC) was observed in response to the 1.95 % Thr diet. Liver proapoptotic factors (bax and caspase9) were significantly elevated in fish fed the 1.39 % Thr diet. The nuclear factor κB (nf-κb) and the NF-κB-mediated inflammatory cytokines were significantly increased in fish fed the 1.39 % Thr diet. The mRNA levels of protein kinase R (PKR)-like endoplasmic reticulum kinase (perk), eukaryotic translation initiation factor 2 (eif2α), activating transcription factor 4 (atf4), and C/EBP-homologous protein (chop), which are factors in the PERK/ATF4/CHOP pathway, one of the unfolded protein response (UPR) signaling pathways, were significantly increased by the 1.39 % Thr diet. The present study showed that low dietary Thr levels caused oxidative damage, reduced immunity, might affected PERK-ATF4-CHOP signaling to induce apoptosis, and via NF-κB signaling to trigger an inflammatory response in largemouth bass. Based on the TP, ALB, CAT, and MDA levels, the dietary Thr requirements for juvenile largemouth bass were estimated to be 2.18 %, 2.29 %, 1.92 %, and 1.88 %. Furthermore, these findings provided a new perspective that low dietary amino acid levels may trigger apoptosis and inflammatory responses in fish through the UPR signaling pathway.

A 9-week experiment investigated the effects of dietary cobalt levels on the growth performance, antioxidant capacity, and immunity of largemouth bass. Six feed groups were designed and each group received different cobalt levels, including 0.129 mg/kg (control group), 0.192 mg/kg, 0.201 mg/kg, 0.233 mg/kg, 0.277 mg/kg, and 0.316 mg/kg. The results show that the control group (0.129 mg/kg diet) had the lowest final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR), and the highest feed conversion ratio (FCR), when compared to the cobalt supplementation groups. Dietary cobalt levels of 0.192 mg/kg increased the body protein content and decreased the body moisture content. Regarding antioxidant capacity, the highest catalase (CAT) activity was found in the 0.277 mg/kg dietary cobalt group, while the malondialdehyde (MDA) content was significantly diminished; the total antioxidant capacity (T-AOC) content and glutathione peroxidase (GSH-Px) activity exhibited the highest values in the 0.192 mg/kg and 0.233 mg/kg dietary cobalt groups, respectively. Regarding gene expression, compared with the control group, the mRNA expression of sod was upregulated in the 0.192 mg/kg, 0.233 mg/kg, and 0.277 mg/kg dietary cobalt groups, while the mRNA expression of gpx was diminished when dietary cobalt levels were below 0.233 mg/kg. In addition, the highest il-10 and tgf-β mRNA expression levels were observed in the 0.201 mg/kg and 0.233 mg/kg dietary cobalt groups, respectively. According to the quadratic regression analysis based on the SGR and FCR, the optimal requirement was 0.24 and 0.26 mg/kg of dietary cobalt, respectively.

The aim of this study was to investigate the effects of S6K1α and β on the expression of glycolysis- and gluconeogenesis-related genes in juvenile blunt snout bream. Two isoforms, α and β, of ribosomal protein S6 kinase 1 in blunt snout bream were cloned and characterized, and their expression patterns were examined in vivo. The sequence analysis showed that s6k1α and s6k1β contain open reading frames of 2217 and 1497 bp, encoding 738 and 498 amino acids, respectively. Both S6K1α and S6K1β consist of an S_TKc domain and an extended S_TK_X domain. s6k1α and s6k1β were abundantly expressed in the heart and gonads. siRNAs were designed, and the experiment showed that α-siRNA inhibited s6k1α and s6k1β expression, but β-siRNA exclusively inhibited s6k1α expression (p < 0.05). α-siRNA upregulated the expression levels of gk and pk, while β-siRNA upregulated pepck and g6p expression (p < 0.05). The expression of g6pdh was found to be downregulated, but the gs mRNA level was overexpressed after treatment with α-siRNA and β-siRNA (p < 0.05). In the present experiment, S6K1α was more intimately involved in the regulation of gluconeogenesis when only S6K1α was inhibited, whereas the inhibition of both S6K1α and S6K1β collectively co-regulated glycolysis.

This experiment evaluated the function of chlorogenic acid (CGA) in the growth, health status, and inflammation of largemouth bass (Micropterus salmoides). Over eight weeks, CGA supplementation was designed at five levels: 0, 60, 120, 180, and 240 mg/kg. The 180 and 240 mg/kg CGA-supplemented groups showed significant improvements in the FBW, SGR, and WGR compared to the control group (0 mg/kg) (p < 0.05). All the CGA-supplemented groups exhibited a significant reduction in the FCR (p < 0.05), with the 180 mg/kg CGA group showing the lowest FCR. Nonetheless, there were no appreciable differences in the plasma concentrations of TP, ALT, or AST among the treatments (p > 0.05). Compared to the control group, the 180 mg/kg CGA group exhibited significantly lower TC and TG levels (p < 0.05). The ALP levels showed no significant differences from the control group (p > 0.05). In terms of antioxidant parameters, CGA supplementation considerably reduced the MDA content (p < 0.05) and increased the GSH levels, while decreasing the CAT, SOD, and GPx activity levels Meanwhile, CGA supplementation resulted in reduced mRNA levels of SOD, CAT, Nrf2, Keap1, and NF-κB compared to the control group. In contrast, the mRNA levels of GPx, IL-8, TLR2, and RelA were elevated in the liver. Our findings indicated that CGA supplementation improved the growth performance and antioxidant status and weakened the inflammatory response of largemouth bass. These findings suggest that CGA could be a valuable dietary supplement for enhancing the health and growth of this species.

An eight-week experiment was conducted to study the effects of dietary ferroporphyrin (FPR) supplementation on growth performance, antioxidant capacity, immune response, and oxygen-carrying capacity in gibel carp. The results demonstrated that the addition of FPR increased the moisture content of the whole fish body. Supplementation with 0.01% FPR significantly increased the plasma albumin (ALB), total protein (TP), and total cholesterol (TC) contents. The addition of 0.03% and 0.04% FPR significantly increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, respectively, while the glucose (GLU), TC, and total triglyceride (TG) levels showed opposite trends. In terms of antioxidant capacity, the 0.03% and 0.04% dietary FPR supplementation increased malondialdehyde (MDA) levels. The activity of glutathione peroxidase (GPx) exhibited an opposite trend to MDA levels. The supplementation of 0.03% of FPR resulted in a notable reduction in mRNA expression levels of nrf2, keap1, cat, and gpx. Regarding immunity, 0.01% FPR supplementation down-regulated the expression levels of il-1β mRNA, while 0.02% FPR down-regulated il-6 and nf-κb expression levels. Furthermore, 0.02% FPR supplementation significantly up-regulated the il-10 mRNA expression levels. In terms of oxygen-carrying capacity, high levels of FPR (0.03% and 0.04%) were found to influence the epo and vegf mRNA expression. In conclusion, the incorporation of dietary 0.01–0.02% FPR improved the immune system of gibel carp without affecting their antioxidant and oxygen-carrying capacity. However, supplementation with higher levels of FPR (0.03–0.04%) led to decreased antioxidant and oxygen-carrying capacity.

This study evaluated the optimal dietary copper (Cu) levels and their effects on growth performance, body composition, and antioxidant capacity in juvenile largemouth bass (Micropterus salmoides). A total of 360 fish (initial average weight (1.67 ± 0.01 g) and initial average length (2.5 ± 0.2 cm)) were randomly assigned to 18 tanks, each containing 20 fish and six dietary Cu concentrations: 2.13 (control), 3.00, 3.66, 4.58, 4.64, and 5.72 mg/kg. The results indicated that fish receiving 3.00 mg/kg of Cu exhibited the best final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR), with a significantly reduced feed conversion ratio (FCR). While body composition (moisture, protein, lipid, and ash) remained consistent across groups, plasma total protein (TP) levels increased with Cu supplementation. Elevated triglycerides (TG) and albumin (ALB) were noted at 4.64 and 5.72 mg/kg, respectively, while glucose (GLU) levels decreased with an increase in dietary Cu. Antioxidant capacity, assessed via hepatic glutathione (GSH) and the activities of catalase (CAT), and showed significant improvements at 3.00 and 3.66 mg/kg Cu, while superoxide dismutase (SOD) showed the highest activity at a dietary Cu level of 5.72 mg/kg. Additionally, the expressions of tgf-β and tnf-α genes were significantly upregulated at a dietary Cu level of 5.72 mg/kg, while il-8 and il-10 genes were upregulated at dietary 3.66 mg/kg. The expression of nrf2 was significantly upregulated in response to a dietary Cu level of 3.66 mg/kg compared to the control group, and the expression of the keap1 gene was significantly upregulated in the fish fed with 5.72 mg/kg of dietary Cu. The results indicated that appropriate dietary supplementation could promote the growth performance and improve the antioxidant status the immunity of largemouth bass, and the optimal Cu requirement for FCR and SGR were approximately 3.10 mg/kg and 3.00 mg/kg, respectively.

To investigate the effects of taurine and vitamin C on gibel carp (Carrassius auratus gibeilo), fish (41.85 ± 0.03 g) were fed three diets with 0% taurine + 0% vitamin C (D0), 0.1% taurine + 0% vitamin C (D1), and 0.1% taurine + 0.1% vitamin C (D2) for 8 weeks. Then 12-hour hypoxic stress test was conducted. The results showed that weight gain rate (WGR), specific growth rate (SGR), and sustained swimming time (SST) were significantly increased in the D2. CAT, SOD, T-AOC, and GSH were increased. GSH-Px and il-6 were decreased in D1 and D2. In hypoxia, CAT and T-AOC were decreased, while GSH, sod, and nrf2 were the highest in D1. Compared to normoxia, GSH-Px was increased, while SOD and MDA were decreased. Il-10 and nf-κb were increased. Vegf, epo, and ho-1 were increased and they all were higher than that in normoxia. The number of gill cell mitochondria and survival rate (SR) of gibel carp had an increasing trend but no significant difference among groups. In conclusion, taurine with vitamin C improved the growth and SST of gibel carp, and taurine and taurine with vitamin C improved antioxidant capacity, immunity, and hypoxia tolerance.

A 95-day experiment was conducted to evaluate the feasibility of partially substituting fishmeal with enzymatic hydrolysate of poultry by-product meal (EHPB) as feed for juvenile largemouth bass (Micropterus salmoides). Five diets (EHPB0, EHPB3, EHPB6, EHPB9, and EHPB12) of fishmeal were 45% (0% EHPB, the control group), 41% (3.1% EHPB), 37% (6.2% EHPB), 33% (9.3% EHPB), and 29% (12.4% EHPB), respectively. The initial mean weigh of largemouth bass was 22.35 ± 0.08 g. There were no significant differences in growth performance among all EHPB groups compared with the control (P > 0.05). The growth performance of EHPB3 was significantly better than that of EHPB12 (P < 0.05). EHPB0 had the highest crude protein and moisture content (P < 0.05). Plasma total cholesterol (TC), triglyceride (TG), and lactate dehydrogenase (LDH) were significantly lower under EHPB9 and EHPB12 than the control (P < 0.05). Low-density lipoprotein (LDL) and alkaline phosphatase (ALP) were significantly lower under EHPB12 than the control (P < 0.05). High-density lipoprotein (HDL), total protein (TP), and albumin (ALB) did not significantly differ among diets (P > 0.05). Hepatic glutathione (GSH) content and glutathione peroxidase (GPx) activity were highest for the control (EHPB0). The hepatic superoxide dismutase (SOD) and catalase (CAT) activity levels were significantly lower for all treatments than the control except for EHPB3 (P < 0.05). Keap1 in the Nrf2 pathway was significantly upregulated and cat was significantly downregulated under all treatments compared with the control except for EHPB3 (P < 0.05). Jnk1/2, nf-κb, il-8/10, tnf-α, and traf2 were significantly upregulated under EHPB6 relative to the control (P < 0.05). The diet containing 29% basal fishmeal (12.4% EHPB) did not affect the growth performance of juvenile largemouth bass. However, the optimal levels of the genes related to antioxidant performance and immune function were attained under 3.1% EHPB (41% fishmeal).

This study investigated the role of cholecystokinin (cck) in the feeding regulation of largemouth bass (Micropterus salmoides) via peptide activation and antagonist inhibition. The results show that the cck gene was expressed in various tissues, with the highest expression level occurring in the brain. Feeding, continuous feeding, and refeeding after fasting could significantly improve the mRNA levels of cck in the brain. Moreover, the activation of cck via injecting an exogenous CCK peptide could inhibit feed intake by regulating the mRNA levels of anorexigenic and feed-promoting factors in the brain and intestine. Furthermore, the CCK peptide reduced feed intake; however, the presence of an antagonist (Ly225910-CCK1R and devazepide-CCK2R) could reverse this effect through regulating the mRNA levels of anorexigenic and feed-promoting factors in the brain and intestine. Treatment with devazepide + CCK (CCK2R) reversed feed intake more effectively than Ly225910 + CCK (CCK1R) treatment. In summary, cck could regulate the feed intake of largemouth bass through regulating feeding-related genes in the brain and intestine. In addition, cck required binding with the receptor to inhibit feed intake more effectively in largemouth bass, and the binding effect of CCK1R was better than that of CCK2R.

This study investigated the effects of replacing 0% (SPC0), 25% (SPC25), 50% (SPC50), 75% (SPC75), and 100% (SPC100) of fish meal (FM) with soy protein concentrate (SPC) on the growth, nutritional metabolism, antioxidant capacity, and inflammatory factors in juvenile largemouth bass (Micropterus salmoides) (17.03 ± 0.01 g). After 56 days of culturing, various growth parameters including FW, WGR, and SGR were not significantly different among SPC0, SPC25, and SPC50 groups; however, they were significantly higher than those in SPC75 and SPC100 groups. Conversely, significantly lower FCR were determined for the SPC0, SPC25, and SPC50 groups compared with that for the SPC100 group; specifically, no significant difference among SPC0, SPC25, and SPC50 groups was found. Moreover, compared with SPC75 and SPC100 groups, a significantly higher FI was observed in the SPC0 group, whereas a significantly lower SR was observed in SPC100 compared with that in SPC0 and SPC25 groups. Compared with the SPC0 group, significantly lower mRNA levels of tor, rps6, 4ebp1, pparγ, and fas were found in SPC75 and SPC100. Additionally, the mRNA levels of cpt were significantly higher in SPC0, SPC25, and SPC50 groups than in SPC75 and SPC100 groups. Moreover, the mRNA levels of scd and acc remained unchanged for all the groups. Replacement of FM with SPC did not significantly affect the mRNA levels of gk, pk, and pepck. Compared with the SPC0 group, significantly decreased activities of CAT were observed in the SPC50, SPC75, and SPC100 groups, and significantly decreased activities of GSH-Px were observed in the SPC75 and SPC100 groups. In addition, significantly lower activity of SOD was observed in SPC100 compared with the other groups. Moreover, compared with the other groups, the SPC75 and SPC100 groups had significantly decreased and increased contents of GSH and MDA, respectively, while significantly lower mRNA levels of nrf2, cat, sod, and gsh-px were found in SPC50, SPC75, and SPC100; however, significantly higher mRNA levels of keap1 were observed in SPC75 and SPC100 groups. Additionally, significantly higher mRNA levels of il-8 and nf-κb were found in the SPC50, SPC75, and SPC100 groups compared with the SPC0 group. Conversely, significantly lower mRNA levels of il-10 and significantly higher mRNA levels of tnf-α were found in the SPC75 and SPC100 groups compared with the other groups. Compared with the SPC0 group, mucosal thickness and villus height were significantly decreased in the SPC75 and SPC100 groups. Collectively, SPC replacing 50% FM did not affect its growth of juvenile largemouth bass. However, SPC replacing 50% or more FM might inhibit antioxidant capacity and immune capacity to even threaten the SR, resulting in impaired intestinal development in replacing FM level of 75% or more.

To reveal the effects of waterborne copper stress on gene expression changes, molecular pathways, and physiological functions in Coilia nasus, juvenile fish were equally divided into two experimental groups, and the copper levels were 1.61 ± 0.03 mg/L (copper-exposed group) and 0 mg/L (control group), respectively. After 4 h, gill tissue samples were collected for transcript sequencing analysis, and two libraries were constructed from the copper treatment group (Cu) and the control group (C) and sequenced using Illumina sequencing technology. The results showed that approximately 40.2–46.0 M clean reads were obtained from each library, and the percentage of uniquely mapped transcripts ranged from 80.57 to 84.93%. A total of 3915 differentially expressed genes (DEGs) were identified under waterborne copper stress, among which 1300 genes were up-regulated, and 2615 genes were down-regulated. Twelve DEGs were randomly selected for quantitative RT-PCR (qRT-PCR) analysis, and the results confirmed that the transcriptome analysis was reliable. Furthermore, the DEGs were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and the results showed that most of the DEGs were involved in metabolic pathways, including steroid biosynthesis, glutathione metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling pathways. Furthermore, due to the waterborne copper levels, gsk-3β was significantly up-regulated, while other metabolism-related genes (tor, pi3k, lpl, aqp7, fabp3) were significantly down-regulated. In addition, the copper-exposed group significantly reduced the expression of some immunity genes (ifn-γ, stat1, cxcl10, and tgf-β), and enhanced the expression of il-1β and tnf-α. In summary, these results indicated that copper causes metabolic disorders and insufficient energy supply in the body, and induces oxidative stress, which results in reduced immune functions.

To improve the breeding efficient of fish, it is crucial to provided essential nutrients based on the nutritional demands. Isoleucine is an essential amino acid, and it plays a significant role in growth and metabolism of largemouth bass. Therefore, this study aimed to investigate the effects of dietary isoleucine on the growth and muscle development of largemouth bass (Micropterus salmoides) by conducting an 8-week feeding experiment. Fish (initial weight 19.97 ± 0.04 g) were randomly distributed into six treatments with three replicate groups of 20 fish and fish were fed diets with varying isoleucine levels (1.47%, 1.68%, 1.93%, 2.30%, 2.46%, and 2.72% of dry diet). Results revealed that isoleucine supplementation increased the specific growth rate (SGR) and significantly decreased the feed conversion ratio (FCR). Moreover, histological analysis of the muscle tissue revealed a significant correlation between the size and density of muscle fibers and isoleucine levels. This alteration may be attributed to the downregulation of myostatin and muscle growth-related genes, MyoD and MyoG, respectively. Additionally, fish fed an isoleucine-supplemented diet showed downregulated expression of apoptosis-related (Caspase-3, Caspase-8, and Caspase-9) and ubiquitin-proteasome pathway-related (Ub, Murf1, Mafbx, and Psmc1) genes (1.93%−2.30%). The muscle and plasma total protein contents showed similar patterns of variation to the gene described above. Furthermore, isoleucine supplementation significantly increased body protein levels and decreased body lipid levels. Quadratic regression analysis revealed that the optimal isoleucine levels for juvenile largemouth bass were 1.997% and 1.837% in the dry diet (4.21% and 3.87% of dietary protein) for SGR and FCR, respectively.

The independent evolution of gigantism among dinosaurs has been a topic of long-standing interest, but it remains unclear if gigantic theropods, the largest bipeds in the fossil record, all achieved massive sizes in the same manner, or through different strategies. We perform multi-element histological analyses on a phylogenetically broad dataset sampled from eight theropod families, with a focus on gigantic tyrannosaurids and carcharodontosaurids, to reconstruct the growth strategies of these lineages and test if particular bones consistently preserve the most complete growth record. We find that in skeletally mature gigantic theropods, weight-bearing bones consistently preserve extensive growth records, whereas nonweight- bearing bones are remodelled and less useful for growth reconstruction, contrary to the pattern observed in smaller theropods and some other dinosaur clades. We find a heterochronic pattern of growth fitting an acceleration model in tyrannosaurids, with allosauroid carcharodontosaurids better fitting a model of hypermorphosis. These divergent growth patterns appear phylogenetically constrained, representing extreme versions of the growth patterns present in smaller coelurosaurs and allosauroids, respectively. This provides the first evidence of a lack of strong mechanistic or physiological constraints on size evolution in the largest bipeds in the fossil record and evidence of one of the longest-living individual dinosaurs ever documented. [ABSTRACT FROM AUTHOR]

This study explored the role of dietary arginine level (DAL) on growth, intestinal antioxidant status and immune response in juvenile largemouth bass (Micropterus salmoides), providing guidance for the optimization of commercial feed in largemouth bass. Six graded arginine levels in diets were fed to the fish for 8 weeks (1.96%, 2.28%, 2.52%, 2.81%, 3.09% and 3.35% diets). The findings were as follows: with increasing DALs, FW, WG and SGR increased first and decreased, and FCR showed the opposite trend. There was no difference in the contents of crude protein and ash among graded DAL (P > 0.05). DAL (3.09% and 3.35%) significantly increased the activities of plasma AST (P

DL-methionyl–DL-methionine (AQUAVI® Met-Met) (Met-Met) (0.10%, 0.20%, 0.30%, and 0.40%) or DL-methionine (DL-Met) (0.10%, 0.20%, 0.30%, and 0.40%) were added to a low-fishmeal diet in an attempt to reduce fishmeal in the diet of Micropterus salmoides (M. salmoides). The fish were randomly allocated into ten experimental groups (n = 100), each with 4 replicates of 25 fish (16.39 ± 0.01 g) each. Compared to 25% FM, 0.40% of DL-Met and 0.10% of Met-Met promoted growth, and 0.10% of Met-Met decreased FCR. Compared to 25% FM, the supplementation of Met-Met or DL-Met improved the intestinal antioxidant capacity by upregulating the NF-E2-related factor 2-mediated antioxidant factors and enzyme activities and nuclear factor kappa-B-mediated anti-inflammatory factors while downregulating the pro-inflammatory factors, thereby exerting anti-inflammatory effects. Moreover, 0.10% of the Met-Met diet affected the Firmicutes-to-Bacteroidota ratio, increased the levels of Proteobacteria, changed the composition of intestinal flora (Roseburia, Lachnospiraceae_NK4A136_group, and unclassified_Oscillospiraceae), and enhanced intestinal dominant bacteria (Caldicoprobacter, Pseudogracilibacillus, and Parasutterella), leading to improved gut health. In summary, the supplementation of DL-Met or Met-Met alleviated the adverse effect of fishmeal reduction (from 40 to 25%) on the growth performance and intestinal health of M. salmoides.