Individual and combined effects of the dietary Spirulina platensis and Bacillus licheniformis supplementation on growth performance, antioxidant capacity, innate immunity, relative gene expression and resistance of goldfish, Carassius auratus to Aeromonas hydrophila.

This study evaluated the individual and combined effects of the dietary Spirulina platensis (SP) and probiotic bacterium Bacillus licheniformis (BL) on the growth performance, immune responses, and disease resistance in goldfish (Carassius auratus). A total of 216 fish (3.39 ± 0.24 g) were randomly distributed in 12 tanks with 18 fish per tank (4 treatments with 3 replications) and fed with diets containing 0% S. platensis and B. licheniformis (T0), 108 CFU/g B. licheniformis (T1), 2.5% S. platensis (T2), and 108 CFU/g B. licheniformis + 2.5% S. platensis (T3(. There were no significant differences in growth parameters. The alternative complement pathway (ACH50) and lysozyme activity were significantly increased in T2 and T3 treatments. No marked differences were observed in total immunoglobulin and protease activity among treatments (P > 0.05). The relative expression of IGF-1 was not affected by experimental diets (P > 0.05). Ghrelin gene showed significantly higher mRNA levels in fish fed with SP and BL (P < 0.05). The relative expression of catalase (CAT), and glutathione reductase (GSR) significantly increased in fish fed with the SP and BL (P < 0.05). No marked difference in glutathione peroxidase (GPX) gene expression was seen between the treatments (P > 0.05). The mRNA levels of lysozyme, IL6, IL-1ß, TGF, and TNF2 transcription were higher in fish fed with SP and BL (P < 0.05). No notable difference was observed in TNF1 and IL10 gene expression between treatments (P > 0.05). Moreover, the result of the challenge test with A. hydrophila showed that goldfish fed with SP and BL had a lower mortality rate than the control. In conclusion, the supplementation of SP and BL can be used as feed additives to enhance disease resistance against A. hydrophila infection by stimulating the immune system in goldfish.

Effect of a diet enriched with sodium propionate on growth performance, antioxidant property, innate-adaptive immune response, and growth-related genes expression in critically endangered beluga sturgeon (Huso huso).

Organic acids are active substances required for improving the productivity and wellbeing of aquatic animals. Herein, the study investigated the effects of sodium propionate on growth performance, antioxidative and immune responses, and growth-related genes expression in beluga sturgeon (Huso huso). For eight weeks, fish fed sodium propionate at 0, 1.2, 2.5, and 5 g kg-1. The final weight, weight gain, and SGR were substantially increased while FCR decreased by dietary sodium propionate at 2.5 and 5 g kg-1 (P < 0.05). The expression of Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) was markedly upregulated (P < 0.05) by dietary sodium propionate in the gills and livers of beluga. The highest mRNA level of GH and IGF-1 has been observed in fish fed a 2.5 g sodium propionate/kg diet. The red blood cells count, and hemoglobin level were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg-1 levels. Further, the hematocrit level was increased (P < 0.05) by a dietary 5 g sodium propionate/kg diet. The total protein level and lysozyme activity were meaningfully increased (P < 0.05) by 2.5 and 5 g sodium propionate/kg diet compared with 0 and 1.2 g kg-1 levels. The highest superoxide dismutase was observed in fish fed 2.5 g sodium propionate/kg diet. Catalase activity was significantly higher in fish fed 5 g kg-1 than 1.2 g kg-1. The glutathione peroxidase activity was markedly higher in fish fed 2.5, and 5 g kg-1 than fish fed control diet. The lowest malondialdehyde levels were observed in fish fed 1.2, and 2.5 g sodium propionate/kg diets. Moreover, the highest mucosal total protein, total immunoglobulin and lysozyme were recorded in fish fed 2.5, and 5 g sodium propionate/kg diets. The obtained results indicate that dietary sodium propionate is recommended at 2.5-5 g kg-1 to improve beluga sturgeon's growth performance, feed utilization, and wellbeing.

Effects of polystyrene microparticles on inflammation, antioxidant enzyme activities, and related gene expression in Nile tilapia (Oreochromis niloticus).

Due to the importance of Nile tilapia in the aquaculture sector, the present study aimed to evaluate the adverse impacts of the polystyrene microparticles (PS-MPs) on inflammation, immune, and antioxidative responses. For this reason, fish were exposed to waterborne PS-MPs at two sizes (9 µm and 0.35 µm) beside the control group for 28 days. Regardless of particle size, the final weight, weight gain, specific growth rate, and feed conversion ratio of Nile tilapia were not influenced by the PS-MPs exposure (P > 0.05). Superoxide dismutase (SOD), glutathione peroxidase (GPX), and malondialdehyde (MDA) levels were significantly increased in the group exposed to 9 µm and followed by those exposed to 0.35 µm while the lowest SOD, GPX, and MDA were in the control group. The expression of catalase (CAT) and lysozyme genes were upregulated in the group of fish exposed to 9 µm (P < 0.05). The expression of the interferon-gamma (IFN-γ) gene was upregulated in fish exposed to 9 µm and 0.35 µm when compared with the control (P < 0.05). The expression of interleukin 8 (IL8), interleukin (IL-1ß), and tumor necrosis factor (TNF-α) genes was upregulated in the group of fish exposed to 9 µm (P < 0.05). The hepatic mRNA levels of cytochrome P450 (CYP450) gene were significantly upregulated in the group of fish exposed to 9 µm when compared with the control (P < 0.05) without significant differences with those exposed to 0.35 µm (P > 0.05). The obtained results refer to the adverse effects of PS-MPs on the antioxidative, inflammatory, and detoxification-related genes of Nile tilapia.

The blood and mRNA levels of antioxidant-related factors in common carp (Cyprinus carpio) fed p-Coumaric acid.

The natural antioxidants are well known for their antioxidative activity without side effects when compared to antibiotics. Hence, the present study aimed at evaluating p-Coumaric acid as an antioxidant additive on the blood and mRNA levels of antioxidant-related factors in common carp (Cyprinus carpio). Fish fed the basal diet supplemented with p-Coumaric at 0, 0.5, 1, and 1.5 g/kg for 56 days, then the serum, intestine, and liver samples were collected. The growth performance of fish fed with CA showed significantly (P < 0.05) improved FW, WG, and SGR compared to those of the control one. However, the feed conversion ratio was significantly (P < 0.05) reduced in fish fed 1 and 1.5 g/kg diet levels. SOD was not significantly differed among the groups fed with varied p-Coumaric acid (P > 0.05). Serum GPX and TAC were enhanced considerably by p-Coumaric acid regarding the control with the highest being in fish fed 1.5 g/kg diet (P < 0.05). Serum CAT was more elevated in fish provided p-Coumaric acid at 1 or 1.5 g/kg than the control while fish fed 0.5 g/kg did not display significant changes. MDA level significantly decreased by all p-Coumaric acid groups compared to the control one, and the lowest level was observed in 1.5 g/kg (P < 0.05). The mRNA level of CAT was significantly upregulated in the liver by p-Coumaric acid at 1 or 1.5 g/kg (P < 0.05), while the intestine CAT did not influence by p-Coumaric acid (P > 0.05). The measured SOD in the liver and intestine samples revealed no changes in common carp fed p-Coumaric acid (P > 0.05). GPX was significantly upregulated in the intestine by p-Coumaric acid at 1 or 1.5 g/kg (P < 0.05), whereas the liver GPX was upregulated by p-Coumaric acid at 1.5 g/kg. The mRNA level of the GST gene in the intestine of common carp was upregulated by p-Coumaric acid at 1.5 g/kg, whereas the liver displayed upregulated GST in fish fed 1 g/kg diet. The present study approved the application of p-Coumaric acid as a natural antioxidant for friendly, sustainable aquaculture.