Background: Collagen is the most abundant structural protein in the mammalian connective tissue and represents approximately 30% of animal protein. The current study evaluated the potential capacity of collagen extract derived from Nile tilapia skin in improving the cutaneous wound healing in rats and investigated the underlying possible mechanisms. A rat model was used, and the experimental design included a control group (CG) and the tilapia collagen treated group (TCG). Full-thickness wounds were conducted on the back of all the rats under general anesthesia, then the tilapia collagen extract was applied topically on the wound area of TCG. Wound areas of the two experimental groups were measured on days 0, 3, 6, 9, 12, and 15 post-wounding. The stages of the wound granulation tissues were detected by histopathologic examination and the expression of vascular endothelial growth factor (VEGF), and transforming growth factor (TGF-ß1) were investigated using immunohistochemistry. Moreover, relative gene expression analysis of transforming growth factor-beta (TGF-ß1), basic fibroblast growth factor (bFGF), and alpha-smooth muscle actin (α-SMA) were quantified by real-time qPCR. Results: The histopathological assessment showed noticeable signs of skin healing in TCG compared to CG. Immunohistochemistry results revealed remarkable enhancement in the expression levels of VEGF and TGF-β1 in TCG. Furthermore, TCG exhibited marked upregulation in the VEGF, bFGF, and α-SMA genes expression. These findings suggested that the topical application of Nile tilapia collagen extract can promote the cutaneous wound healing process in rats, which could be attributed to its stimulating effect on recruiting and activating macrophages to produce chemotactic growth factors, fibroblast proliferation, and angiogenesis. Conclusions: The collagen extract could, therefore, be a potential biomaterial for cutaneous wound healing therapeutics.

Ammonia is a critical hazardous nitrogen metabolic product in aquaculture. Despite trials for its control, ammonia intoxication remains one of the most critical issues to overcome. In this study, we explored the modulatory effect and potential mechanism by which Yucca schidigera extract (YSE) can ameliorate ammonia intoxication-induced adverse effects on tilapia health and metabolism. A total number of 120 Nile tilapia were evenly assigned into four groups with three replicates each. The first group served as normal control group; the second group was exposed to ammonia alone from the beginning of the experiment and for four weeks. The third group was supplied with YSE in water at a dose of 8 mg/L and exposed to ammonia. The fourth group was supplied with YSE only in water at a dose of 8 mg/L. YSE supplementation succeeded in improving water quality by reducing pH and ammonia levels. Moreover, YSE supplementation markedly alleviated chronic ammonia-induced adverse impacts on fish growth by increasing the final body weight (FBW), specific growth rate (SGR), feed intake and protein efficiency ratio (PER) while reducing the feed conversion ratio (FCR) via improvements in food intake, elevation of hepatic insulin-like growth factor (ILGF-1) and suppression of myostatin (MSTN) expression levels with the restoration of lipid reserves and the activation of lipogenic potential in adipose tissue as demonstrated by changes in the circulating metabolite levels. In addition, the levels of hepato-renal injury biomarkers were restored, hepatic lipid peroxidation was inhibited and the levels of hepatic antioxidant biomarkers were enhanced. Therefore, the current study suggests that YSE supplementation exerted an ameliorative role against chronic ammonia-induced oxidative stress and toxic effects due to its free radical-scavenging potential, potent antioxidant activities and anti-inflammatory effects.

The antioxidant and detoxification systems involve intricate pathways in which nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) play pivotal roles. In the basal state, reactive oxygen species are generated and neutralized in a balanced manner. However, stressors can disrupt this equilibrium, resulting in oxidative stress and cellular damage. In this study, we analyzed the expression of nrf2 and keap1 in Nile tilapia (Oreochromis niloticus) under homeostasis and challenge with Aeromonas hydrophila. During homeostasis, the predominant expression of nrf2 was observed in the liver, blood, muscle, gut, and gills, while keap1 was highly expressed in the brain, liver, blood, spleen, eye, head kidney, and gills. After the challenge, the spleen demonstrated the highest keap1 expression, while the liver displayed the highest nrf2 levels among the tissues examined. Apparently, our findings suggest that the spleen may be susceptible to initial damage following infection, leading to the manifestation of the first lesion. This susceptibility could be attributed to the spleen’s high expression of keap1, acting as a negative regulator of nrf2. Notably, a positive correlation was observed between nrf2 and keap1 expression in several tissues, with the strongest association observed in the blood, gills, and head kidney under both normal and inflammatory conditions. Our findings indicate that blood may serve as a crucial mediator of Nrf2/Keap1 signaling in tissues like the liver and gut during normal and inflammatory states. By shedding light on the altered expression and correlation of nrf2 and keap1 in various tissues, this study elucidates their potential connection to antioxidant and immune responses, as well as the pathological features of A. hydrophila infection.

The danger posed by waterborne toxicity from herbicides endangers the aquatic ecosystem. Using dietary medicinal herbs is a useful approach to mitigate the effects of herbicide toxicity on aquatic animals. This study attempts to examine the consequences and potential mechanisms behind the dietary addition of horseradish tree (Moringa oleifera) leaf extract (MOLE) with the help of phytase addition to check the overall growth performance, biochemical changes, histological alteration, and gene expression in normal and after glyphosate challenge in Nile tilapia. A total number of 135 Nile tilapia fish (7.93 $$\pm$$ 0.03 g) were randomly assigned into three groups each in triplicate. The first group is the control group and fed basal diet; the second group supplied with MOLE (200 mg of extract/kg), and the third group was supplied with MOLE (200 mg /kg), and phytase (0.2g/ kg) for 8 weeks. After the feeding trial, each experimental group was divided into two subgroups to be unchallenged and challenged with glyphosate (30 mg/L of water). The results declared significant enhancements (P < 0.05) in Weight Gain Percent (WG%), Specific growth rate (SGR), and Protein efficiency ratio (PER) and reducing feed conversion ratio (FCR) with up-regulating hepatic gh, igf1,myogenine, intestinal ghrelin and NPY in fish groups fed MOLE and phytase compared with the control group. Moreover, improving the hepatic antioxidant capacity while down-regulating hepatic igf1bp, myostatin. Interstingly, MOLE and phytase lightened glyphosate-induced biochemical alterations, antioxidants, apoptosis, and inflammation-associated genes compared to the glyphosate-challenged group. Interestingly, UPLC-ESI-MS/MS analysis recognized 16 compounds encompasing two glucosinolates, three flavonoids, one phenolic and three alkaloids in addition to four fatty acids, a terpenoid, one phytate and an aromatic glycoside. These components might be accountable for the potential effects exerted by MOLE. Therefore, the current study suggests that dietary supplementation to MOLE and phytase can be used as substitute feed supplements in sustainable farming of Nile tilapia to defend against glyphosate challenges and enhance growth, antioxidant capacity, exerting anti-inflammatory and antiapoptotic effects under normal health conditions or post glyphosate challenge.