The effects of ethoxyquin and Angelica sinensis extracts on lipid oxidation in fish feeds and growth, digestive and absorptive capacities and antioxidant status in juvenile red carp (Cyprinus carpio var. xingguonensis): a comparative study

Transcriptomic and metabolomic analysis revealed potential mechanisms of growth and disease resistance dimorphism in male and female common carp (Cyprinus carpio)

Sexual dimorphism is well-documented in aquaculture, particularly regarding growth differences, wherein one sex often grows faster than the other. However, despite the phenomenon being so widely documented, its underlying molecular mechanisms remain poorly understood. As an important digestive and immune organ, the gut plays key roles in the regulation of fish growth. In this study, we conducted RNA-seq and metabolomic analysis on the gut of female and male common carp. We discovered that growth-related pathways, such as "Glycolysis/Gluconeogenesis" and "Riboflavin metabolism" are significantly enriched in the gut of female carp. Conversely, pathways linked to disease resistance, such as "Th17 cell differentiation" and "Autophagy-animal" are predominantly enriched in male carp. Following intraperitoneal injection of spring viraemia of carp virus (SVCV) into both male and female carp, quantitative reverse transcription polymerase chain reaction (RT-qPCR) analysis and histopathological staining confirmed that male carp exhibit greater disease resistance compared to females. This study identified the disease resistance dimorphism in common carp and specific mechanisms underlying growth differences. Our findings offer valuable insights for the application of growth dimorphism and disease-resistant breeding in fish.

Substituting ethoxyquin with tea polyphenols and propyl gallate enhanced feed oxidative stability, broiler hepatic antioxidant capacity and gut health

The safety of ethoxyquin has garnered increasing attention. This study evaluated the effects of partially substituting ethoxyquin with tea polyphenols and propyl gallate on feed oxidative stability, hepatic antioxidant properties, intestinal morphology and barrier functions, as well as the antioxidant and anti-inflammatory profiles of the intestinal mucosa in broilers. A total of 351 one-day-old male Arbor Acres Plus broilers were randomly assigned to 3 groups, each comprising 9 replicates with 13 birds per replicate. The treatments included a control group (CON) fed a basal diet, an ethoxyquin group (EQ) that received the basal diet supplemented with 120 g/t of ethoxyquin, and a substitution group (TP) receiving the basal diet supplemented with 6 g/t of tea polyphenols, 6 g/t of propyl gallate, and 30 g/t of ethoxyquin. In vitro experiments showed that both EQ and TP supplementation significantly reduced the acid value (AV), peroxide value (POV), and total oxidation value (TOV) of the feeds, with the TP group exhibiting lower AV and TOV than the EQ group. In vivo assessments revealed no significant differences in growth performance among the groups. Additionally, the TP group exhibited significantly higher glutathione peroxidase activity, increased glutathione content, and elevated protein expression of Keap1, Nrf2, and NQO1 in the liver compared to the control group (P < 0.05). Moreover, dietary TP significantly increased liver catalase activity, glutathione content, and NQO1 protein levels compared to the EQ group (P < 0.05). Both additives effectively reduced malondialdehyde levels in the intestinal mucosa by approximately 50% (P < 0.05) through the activation of the Nrf2/ARE pathway, as indicated by increased mRNA expression of TXN, CAT, GPX1, and GPX4 (P < 0.05). Furthermore, compared to the control group, the TP group exhibited greater villus height and villus height-to-crypt depth ratio (VCR) in the jejunum, as well as elevated VCR in the ileum (P < 0.05). The TP group also achieved the lowest serum levels of diamine oxidase activity, D-lactate and lipopolysaccharide contents among all groups (P < 0.05). The inclusion of both EQ and TP increased the mRNA expression of Occludin, Claudin-1, Mucin-2, and E-cadherin in the jejunum (P < 0.05). Moreover, the combination of tea polyphenols and propyl gallate effectively mitigated the proinflammatory effect of ethoxyquin, as evidenced by reductions in TNF-α, IL-18, and IFN-γ expression, potentially mediated by inhibition of the TLR-4/MyD88/NF-κB signaling pathway. In conclusion, this study demonstrates that partially replacing ethoxyquin with tea polyphenols and propyl gallate enhances feed oxidative stability, liver antioxidant capacity, and gut health in broilers, suggesting an efficient alternative with a lower dosage requirement.

Ethoxyquin attenuates enteric oxidative stress and inflammation by promoting cytokine expressions and symbiotic microbiota in heat-stressed broilers

Intestinal oxidative stress in broilers is produced by chronic heat stress (HS) and has a negative impact on poultry performance as it induces intestinal inflammation and promotes the invasion of gram-negative bacteria, such as bacterial lipopolysaccharide (LPS). Therefore, dietary inclusion of the antioxidant compound, ethoxyquin (EQ), could improve enteric antioxidant capacity, immune responses, and the epithelial barrier, and maintain the symbiotic gut microbiota community. To investigate the effects of EQ supplementation on alleviating enteric oxidative stress in heat-stressed broilers, 200 one-day-old male Ross 308 broilers were randomly assigned to 4 groups (n = 50 chicks/group; n = 10 chicks/replicate) and fed a basal diet supplemented with 0 (CT), 50 (EQ-50), 100 (EQ-100), and 200 (EQ-200) mg EQ/ kg-1 for 5 wk. The chicks were raised in floor pens inside the broiler farm at a temperature and humidity index (THI) of 29 from d 21 to d 35. Growth performance traits, relative organ index, hepatic antioxidant enzymes, serum immunity, total adenylate, and cytokine activities were improved in the EQ-50 group (linear or quadratic P < 0.05), promoting the relative mRNA expression of cytokine gene-related anti-inflammatory and growth factors. A distinct microbial community colonised the gut microbiota in the EQ-50 group, with a high relative abundance of Lactobacillus, Ligilactobacillus, Limosilactobacillus, Pediococcus, Blautia, and Faecalibacterium compared to the other groups. Dietary supplementation with 50 mg EQ/ kg-1 for 5 wk attenuates enteric oxidative stress and intestinal inflammation by enhancing serum immune and cytokine content (IgG, IL-6, and TGF-β,) and symbiotic microbiota in heat-stressed broilers. EQ promotes the expression of Hsp70, SOD2, GPx 4, IL-6, and IGF-1 cytokine gene-related anti-inflammatory and growth factors in heat-stressed hepatic broilers. Collectively, EQ-50 could be a suitable feed supplement for attenuating enteric oxidative stress and intestinal inflammation, thereby promoting the productivity of heat-stressed broilers.

Insights into the molecular mechanisms, structure-activity relationships and application prospects of polysaccharides by regulating Nrf2-mediated antioxidant response

The occurrence and development of many diseases are closely related to oxidative stress. In this context, accumulating evidence suggests that Nrf2, as the master switch of cellular antioxidant signaling, plays a central role in controlling the expression of antioxidant genes. The core molecular mechanism of polysaccharides treatment of oxidative stress-induced diseases is to activate Keap1/Nrf2/ARE signaling pathway, promote nuclear translocation of Nrf2, and up-regulate the expression of antioxidant enzymes. However, recent studies have shown that other signaling pathways in which polysaccharides exert antioxidant effects, such as PI3K/Akt/GSK3β, JNK/Nrf2 and NF-κB, have complex crosstalk with Keap1/Nrf2/ARE, may have direct effects on the nuclear translocation of Nrf2. This suggests a new strategy for designing polysaccharides as modulators of Nrf2-dependent pathways to target the antioxidant response. Therefore, in this work, we investigate the crosstalk between Keap1/Nrf2/ARE and other antioxidant signaling pathways of polysaccharides by regulating Nrf2-mediated antioxidant response. For the first time, the structural-activity relationship of polysaccharides, including molecular weight, monosaccharide composition, and glycosidic linkage, is systematically elucidated using principal component analysis and cluster analysis. This review also summarizes the application of antioxidant polysaccharides in food, animal production, cosmetics and biomaterials. The paper has significant reference value for screening antioxidant polysaccharides targeting Nrf2.

The Extract of Angelica sinensis Inhibits Hypoxia-Reoxygenation and Copper-Induced Oxidative Lesions and Apoptosis in Branchiae and Red Blood Corpuscles of Fish

The study explored the effects of Angelica sinensis extract (AsE) on oxidative lesions and apoptosis in branchiae and red blood corpuscles in hypoxia-reoxygenation (HR) and Cu-treated carp (Cyprinus carpio var. Jian). After feeding trial for 30 days, the carp were exposed to HR and CuSO4. The results indicated that dietary AsE increased the durative time, decreased the oxygen consumption rate, suppressed ROS generation and cellular component oxidation, decreased enzymatic antioxidant activity and reduced glutathione (GSH) levels in red blood corpuscles and branchiae in carp under hypoxia. Moreover, dietary AsE avoided the loss of Na+,K+-ATPase, metabolic and antioxidant enzyme activities, ROS generation and cellular component oxidation, as well as the increase in caspase-8, 9, and 3 activities in the branchiae of the carp and inhibited ROS generation. It furthermore avoided the loss of Na+,K+-ATPase and metabolic enzyme activities, the decrease in GSH levels and hemoglobin content, the increase in the activities of caspase-8, 9, and 3 and the increase in the levels of cytochrome c and phosphatidylserine exposure in the red blood corpuscles of Cu-exposed carp. The present results suggested that dietary AsE improved hypoxia tolerance and inhibited HR or Cu-triggered oxidative lesions and apoptosis. Therefore, AsE can be utilized as a natural inhibitor of Cu and HR stress in fish.

Comprehensive quality evaluation of two different geography originated Angelica sinensis Radix based on potential production area development and resource protection

Angelica sinensis Radix (ASR) is mainly produced in the southern region of Gansu, China, and is a famous edible and medicinal herb. Noticeably, Aba region in Sichuan, China has similar geographical and climatic conditions to the southern region of Gansu, China, and has the potential to further develop the ASR planting industry chain. This study was the first to use an innovative method that combines GC-MS, HPLC-DAD fingerprints, and stoichiometric analysis to compare and explore the feasibility of using the Aba region as a source of high-quality ASR supplements. GC-MS analysis showed that the composition of ASR essential oil(AEO) in these two regions was highly similar (>99%). The HPLC data showed that the main sources of differences in ASR components between the two regions were coniferyl ferulate, E-ligustilide, Z-ligustilide, and Butylidenephthalide, which have great potential in anti-depression, regulating gut microbiota, and other aspects. The ASR in Aba region was rich in these components, and its biological activity might be higher to some extent than that in southern Gansu. This study confirmed the potential of the Aba region in Sichuan to become a high-quality production area for ASR, which was conducive to the expansion of ASR resources and the development of related industrial chains.

Integrated biomarker parameters response to the toxic effects of high stocking density, CuSO4, and trichlorfon on fish and protective role mediated by Angelica sinensis extract

The present study explored the protective role of dietary the extract of Angelica sinensis (EAs) on high density, CuSO₄, or trichlorfon-treated Crucian carp (Carassius auratus auratus). Firstly, the study showed that the optimum density for growth and growth inhibition was 0.49 and 0.98 fish L^-1 water, respectively. Dietary EAs relieved the high density-induced growth inhibition in Crucian carp. The appropriate concentration of EAs for recovery of growth was estimated to be 4.30 g kg^-1 diet in high-density fish. Moreover, high density decreased both digestive and absorptive enzyme activities and increased lipid oxidation in digestive organs, suggesting the ability of high density to induce oxidative damage. However, dietary EAs inhibited the oxidative damage through elevating ROS scavenging ability and enzymatic antioxidant activity in digestive organs. Secondly, our data demonstrated that the appropriate concentration of CuSO₄ to induce the decrease in feed intake (FI) was 0.8 mg Cu L^-1 water. Dietary EAs returned to FI of Crucian carp treated with CuSO₄. The appropriate concentration of EAs for recovery of FI was estimated to be 4.25 g kg^-1 diet. Moreover, dietary EAs suppressed the CuSO₄-induced decrease in digestion and absorption capacity and increase in protein metabolism in digestive organs of Crucian carp. Finally, the present results suggested that dietary EAs inhibited the trichlorfon-induced rollover (loss of equilibrium) in Crucian carp. The appropriate concentration of EAs for inhibition of rollover was estimated to be 4.18 g kg^-1 diet. Moreover, trichlorfon stimulated not only the decrease in energy metabolism but also lipid and protein oxidation, suggesting that trichlorfon caused loss of function and oxidative damage in muscles of fish. However, dietary EAs improved muscular function and inhibited oxidative damage via quenching ROS and elevating non-enzymatic and enzymatic antioxidant activity in muscles of trichlorfon-induced fish. So, EAs could be used as an inhibitor of high density, CuSO₄, and trichlorfon stress in fish.

Effects of traditional Chinese medicines on immunity and culturable gut microflora to Oncorhynchus masou

The present study was conducted to evaluate the effect of dietary traditional Chinese medicines on the growth, immunity, and composition of culturable gut microflora in Oncorhynchus masou. Diets were formulated to contain no medicine (control), antitoxic decoction (A), general antiphlogistic decoction (B), or Herbae Artemisiae Capillariae decoction (C). Fish were manually fed twice daily till apparent satiation for 30 days. Compared with that in the control group, supplementation with the three kinds of Chinese herbal medicine enhanced fish growth significantly (P < 0.05). The activities of liver superoxide dismutase and glutathione peroxidase in the treatment groups were significantly higher compared with those in the control group (P < 0.05). The quantity of intestinal microflora was higher in the treatment groups compared with that in the control group. Moreover, there were some effects of dietary Chinese herbal medicine on the composition of intestinal microflora. Microflora of Pseudomonas sp., Psychrobacter sp., Microbacterium sp., Macrococcus sp., Burkholderia sp., and Arthrobacter sp. were found in the treatment groups, whereas there were none in the control group. There was a significant increase in their amounts in the treatment groups (P < 0.05). The three kinds of traditional Chinese medicines can improve the growth and immunity of Oncorhynchus masou and affect the quantity and composition of intestinal microflora.