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Intensive aquaculture causes a decline in the health status of fish, resulting in an increased disease incidence. To counteract this, feed additives have been utilized to improve the growth performance and health of aquaculture species. This work specifically investigates the impact of powdered Ficus deltoidea (FD) on various parameters related to growth, blood parameters, liver and intestine morphology, body proximate analysis, digestive enzymes, antioxidant capacity, and disease resistance to motile Aeromonad Septicemia (MAS) caused by Aeromonas hydrophila infection in African catfish, Clarias gariepinus. Four formulated diets were prepared: T1 (0% FD), T2 (0.5% FD), T3 (0.75% FD), and T4 (1% FD). After 8 weeks, the African catfish's growth performance fed with the T2 diet exhibited a substantial improvement (p < 0.05), along with a remarkably lower (p < 0.05) feed conversion ratio (FCR) when compared to the other treatment groups. Blood parameter analysis revealed notably higher (p < 0.05) levels of white blood cell (WBC), lymphocytosis (LYM), hemoglobin (HGB), albumin (ALB), globulin (GLOB), as well as total protein (TP) in the T2 diet group. While all treatment groups displayed normal intestinal morphology, liver deterioration was observed in groups supplemented with higher FD. The T2 diet group recorded the highest villus length, width, and crypt depth. Protease and lipase levels were also notably improved in the T2 diet group compared to other treatment groups. Additionally, catalase (CAT), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were remarkably elevated in all FD diet groups than in the control group. The expression of immune-related genes, including transforming growth factor beta 1, heat shock protein 90, nuclear factor kappa-B gene, and lysozyme G, was upregulated in all treatments. Overall, the results of this study indicate that incorporating dietary FD at 0.5% concentration in the diet of African catfish may enhance their productivity in intensive farming., Competing Interests: Declarations Ethics approval Not applicable. Consent to participate Not applicable. Consent for publication Not applicable. Competing interests The authors declare no competing interests.., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Aquaculture has intensified tremendously with the increasing demand for protein sources as the global population grows. However, this industry is plagued with major challenges such as poor growth performance, the lack of a proper environment, and immune system impairment, thus creating stress for the aquaculture species and risking disease outbreaks. Currently, prophylactics such as antibiotics, vaccines, prebiotics, probiotics, and phytobiotics are utilized to minimize the negative impacts of high-density farming. One of the promising prophylactic agents incorporated in fish feed is resveratrol, a commercial phytophenol derived via the methanol extraction method. Recent studies have revealed many beneficial effects of resveratrol in aquatic animals. Therefore, this review discusses and summarizes the roles of resveratrol in improving growth performance, flesh quality, immune system, antioxidant capacity, disease resistance, stress mitigation, and potential combination with other prophylactic agents for aquatic animals., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

This study was designed to determine the effects of papaya peel extract (PPE) supplementation on the growth and immunophysiological responses of rohu fingerlings at different stocking densities. In this study, three isonitrogenous (307.2-309.8 g kg -1 protein) and isocaloric diets (16.10-16.16 MJ digestible energy kg -1 ) were prepared using three different inclusion levels (0, 5, and 10 g kg -1 ) of PPE. Four hundred and five rohu fingerlings (mean weight: 4.24 g ± 0.12) were randomly distributed into nine treatment groups in triplicates viz. low (10nos 75 L -1 or ≈ 0.565 kg/m 3 ), medium (15nos 75 L -1 or ≈ 0.848 kg/m 3 ), and high (20nos 75 L -1 or ≈ 1.13 kg/m 3 ) following a completely randomized design. The study found that increasing stocking density negatively affected fish growth indices, such as weight gain percentage (WG%), feed efficiency ratio (FER), specific growth rate (SGR) and survival. In contrast, dietary PPE supplementation improved growth indices and survival (p < 0.05). We also observed that aminotransferase, lactate (LDH), and malate dehydrogenase (MDH) activity increased with stocking density, whereas 5 and 10 g kg -1 PPE supplementation reduced LDH and MDH activity (p < 0.05). PPE supplementation positively affected serum indices, decreased glucose levels, and increased respiratory burst activity (p < 0.05). Interferon-gamma (IFN-γ) expression was highest in the low- and medium-stocking density groups fed with 5 g kg -1 PPE, which also increased total immunoglobulin and myeloperoxidase activity while decreasing malondialdehyde concentration (p < 0.05). The results revealed that 5 g kg -1 dietary PPE supplementation could be used as a growth promoter and immunostimulant to improve immuno-physiological responses at low and medium stocking densities., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

The present study was executed to evaluate the effect of photoperiod on serum biochemical parameters (glucose, cortisol, ALT, AST and LDH), electrolytic balance (Sodium and potassium), acute phase response (CRP) and histopathology (liver, kidney and skin) of an endangered high valued catfish, Ompok bimaculatus. Catfish (21.00 ± 1.53 cm and 30.00 ± 2.31 g) from the acclimatized stock were randomly distributed to six 120 × 45 × 60 cm 3 FRP tanks (n = 20 fish per tank) and exposed to 1500 lx light intensity under different photoperiods [24:0 light: dark (L: D), 15L: 9D, 12L: 12D, 9L: 15D, 0L: 24D and a natural photoperiod (control)], and fed at a daily rate of 2% of bodyweight, twice a day for 60 days. Serum glucose, cortisol and enzymes including aspartate transaminase (AST), lactate dehydrogenase (LDH), alanine transaminase (ALT), and acute phase reactant, such as C-reactive protein (CRP) increased significantly (P < 0.05) in continuous light (24L: 0D), continuous dark (0L: 24D) and short day (9L: 15D) photoperiods, whereas in 15L: 9D and 12L:12D photoperiods, those were in decreasing trend. Serum electrolytes, i.e. potassium level was elevated and sodium level was declined in 24L: 0D, 0L: 24D and 9L: 15D photoperiod groups. Moreover, significant histological alterations in the liver, kidney and skin tissue were also evidenced in the experimented catfish. Typical polygonal hepatocytes with normal blood vessels in liver and normal organization of kidney were seen in catfish of 15L: 9D group. Histological analysis of other groups displayed nuclear degeneration, karyorrhexis, karyolysis, melanomacrophages, nuclear hypertrophy, sinusoid dilation and vacuolar degeneration in liver and hyaline droplets accumulation, granular degeneration, fragmentation of glomerulus and focal necrosis of epithelial cells in kidney. Additionally, general structure of the skin was observed in control group as well as in 15L: 9D group. Contrarily, in 24L: 0D group increased number of mucous cells and vacuoles was observed in the skin of butter catfish. In 9L: 15D and 0L: 24D photoperiods, O. bimaculatus exhibited ruptured epithelial cells, enlarged alarm cells, fat cells, necrotic cells and vacuoles in the skin tissue. The present study depicted that 15L: 9D photoperiod can induce better health of catfish, O. bimaculatus, which, in turn, can help farmers to increase the production of this high valued catfish in future., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

A 30-day experiment was carried out to know responses of different weaning approaches to the growth and survival of Anabas testudineus larvae. A total of 10800 larvae (Avg. weight 0.016 ± 0.03 mg; 3DPH) were randomly distributed in nine treatments (triplicates), including two controls. The strategies are as follows: C1 (Control I): feeding with live food (LF) for 30 days and C2 (Control II): feeding with microparticulate diet (MPD) for 30 days; T1: LF for 5 days and MPD for next 25 days; T2: LF for 10 days and MPD for next 20 days; T3: LF for 15 days and MPD for next 15 day; T4: LF for 20 days and MPD for next 10 days; T5: LF for 25 days and MPD for next 5 days; T6: LF for 5 days, then 25% LF replacement by MPD for next 5 days, 50% LF replacement by MPD for next 5 days, 75% LF replacement by MPD for next 5 days, and 100% LF replacement by MPD for last 10 days; and T7: LF for 10 days, then 25% LF replacement by MPD for next 5 days, 50% LF replacement by MPD for next 5 days, 75% LF replacement by MPD for next 5 days, and 100% LF replacement by MPD for last 5 days. Significantly (p < 0.05) higher WG and SGR were recorded in T2 (213.17 ± 0.32, 23.98 ± 0.02) followed by T6, whereas the lowest was found in C2. Significantly higher (p < 0.05) percentage survival was manifested in the T7 (31.83 ± 0.22), followed by T2 (24.75 ± 0.13), and the lowest survival was observed in the C2. The digestive enzyme activities were found to be non-significant (p > 0.05) between different treatment groups. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH) were reported to be significantly higher (p < 0.05) in C2 (68.52 ± 0.08, 19.55 ± 0.10, 21.79 ± 0.04, and 0.044 ± 0.01) followed by T1; however, their reduced level was observed in C1. The activity of superoxide dismutase (SOD), catalase (CAT), glucose, and cortisol levels was observed significantly (p < 0.05) higher in C2 and lower in C1 and T2. As per the finding, it can be recommended that the appropriate weaning time for A. testudineus larvae is from 13 DPH onwards, in which larvae can be fed an initial ten days LF afterward MPD and the best weaning strategy can be adopted as in the T7 group for higher survival percentage., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Aquatic bacterial pathogens can cause severe economic loss in aquaculture industry. An opportunistic pathogen, Aeromonas hydrophila is responsible for Motile Aeromonas Septicemia, leading to high mortality rates in fish. The present study was focused on the efficacy of Aloe barbadensis replacing fishmeal diets on hematological, serum biochemical, antioxidant, histopathological parameters, and disease resistance against A. hydrophila infection in Labeo rohita. Isonitrogenous fishmeal replaced diets (FMR) were prepared with varying levels of A. barbadensis at D1 (0%) (control), D2 (25%), D3 (50%), D4 (75%) and D5 (100%) then fed to L. rohita. After 60 days of post-feeding, the experimental fish were challenged with A. hydrophila. Blood and organs were collected and examined at 1- and 15-days post infection (dpi). The results demonstrated that on 1 dpi, white blood cells (WBC), total protein, cholesterol and low-density lipoprotein (LDL) levels were significantly increased in D3 diet fed groups. The D2 and D3 diet fed group showed decreasing trends of serum glutamic pyruvic transaminase (SGPT) and antioxidant enzymes activity on 15 dpi. The histopathological architecture results clearly illustrated that the D3 diet fed group had given a higher protective effect by reducing the pathological changes associated with A. hydrophila infection in liver, intestine and muscle. Higher percentage of survival rate was also observed in D3 diet fed group. Therefore, the present study suggested that the dietary administration of A. barbadensis up to 50% fishmeal replacement (D3 diet) can elicit earlier antioxidant activity, innate immune response and improve survival rate in L. rohita against A. hydrophila infection., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

The aquaculture industry's rapid growth to meet commercial demand can trigger an outbreak of infectious diseases due to high-density farming. Antibiotic overuse and misuse in fish farming and its global health consequences have led to searching for more natural alternatives such as medicinal plants. In this sense, garlic (Allium sativum) has different bioactive compounds with biological properties for animal health. Among them are the ajoene, alliin, and allicin, which confer biological properties such as growth promotion, antimicrobial, antiviral, antioxidant, and antiparasitic. Ways to use garlic in aquaculture include oil, fresh mash, aqueous extract, and garlic powder. The powder presentation is the most used in aquaculture; it is generally applied by oral administration, adding to the feed, and the dose used ranges from 0.05 to 40 g/kg of feed. Garlic has been used in the aquaculture of different species such as rainbow trout (Oncorhynchus mykiss), spotted grouper (Epinephelus coioides), catfish (Clarias gariepinus), tilapia (Oreochromis niloticus), guppy fish (Poecilia reticulata), goldfish (Carassius auratus), and barramundi (Lates calcarifer). In addition to its properties, garlic's usage became popular, thanks to its low cost, easy incorporation into food, and little environmental impact. Therefore, its application can be an effective solution to combat diseases, improve organisms' health using natural supplies, and as an alternative to antibiotics. This review reports and discusses plant-derived products' beneficial properties, emphasizing garlic and its usages in fish aquaculture., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)