Supplementation of AQUAGEST ® as a Source of Medium-Chain Fatty Acids and Taurine Improved the Growth Performance, Intestinal Histomorphology, and Immune Response of Common Carp ( Cyprinus carpio ) Fed Low Fish Meal Diets

Hermetia illucens larvae oil as an alternative lipid source: Effects on immune function, antioxidant activity, and inflammatory response in gilthead seabream juveniles

Hermetia illucens larvae oil (HIO) is a promising new ingredient that can potentially be an alternative lipid source in aquafeeds. To assess its viability in gilthead seabream juvenile diets, a 10-week feeding trial was performed, and the effects on antioxidant, immune, and inflammatory responses were evaluated. Four diets were formulated to include HIO at increasing levels: 0, 4, 7.9, and 9.5 %, replacing a vegetable oil mix at 0, 42 %, 84 %, and 100 %, respectively. At the end of the trial, no significant changes were detected in the plasma immune humoral parameters, except for a linear increase in plasma peroxidase activity. Hepatic lipid peroxidation (LPO) remained unchanged, while the activity of antioxidant enzymes showed a linear increase corresponding to the level of dietary HIO inclusion. Fish fed the HIO diets exhibited lower intestinal LPO, and no differences between groups were observed in the activity of the oxidative stress-related enzymes. Regarding the inflammation-related genes, the different diets did not affect interleukin-1β and transforming growth factor β expressions in the intestine. In contrast, upregulation of tumor necrosis factor α and interleukin-10 was observed, being higher in fish fed the diet with total vegetable oil replacement than the others. In conclusion, these findings suggest that Hermetia illucens larvae oil can be included at levels up to 7.9 % of gilthead seabream juvenile diets without compromising their immune, antioxidant, and inflammatory responses while enhancing intestinal LPO.

Nutritional impact of nano zeolite, probiotic, and fatty acids as feed additives on health status of Nile tilapia (Oreochromis niloticus)

For human consumption, fish is a good and affordable source of several crucial elements. Growing aquaculture management and output is always necessary. Therefore, this study was designed to evaluate the effect of probiotics, nano zeolite, and/or medium chain fatty acids (MCFA) on fish health and the chemical composition of the fish body. The experimental fish were distributed into eight groups. T1: Control group fed the basal diet without feed additives, T2: Nano zeolite at a rate of 2 mg/kg diet, T3: Pedococcus at a rate of 2 gm kg diet, T4: Medium chain fatty acids used according to produced company recommendation at a rate of 3.5 gm/kg diet, T5: Nano zeolite (2 mg/kg diet) + Pedococcus (2 mg/kg diet), T6: Nano zeolite (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet), T7: Pedococcus (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet), and T8: Nano zeolite (2 mg/kg diet) + Pedococcus (2 mg/kg diet) + Medium chain fatty acids (3.5 gm/kg diet). The obtained results showed an insignificant difference in the body composition of Nile tilapia fish fed feed additives alone or in combination. Moreover, the feed additives did not affect the health status of fish, as indicated by normal liver and kidney functions.

Effects of exogenous taurine supplementation on the growth, antioxidant capacity, intestine immunity, and resistance against Streptococcus agalactiae in juvenile golden pompano (Trachinotus ovatus) fed with a low-fishmeal diet

Taurine has various biological functions in fish, playing an essential role in growth, resistance to oxidative stress, and intestine immunity. Here, we evaluated the effects of exogenous taurine added to low-fishmeal diets on the growth, anti-oxidative stress, intestine immunity, and Streptococcus agalactiae resistance in juvenile golden pompano (Trachinotus ovatus). Our study showed that exogenous taurine supplementation of 1.2% (T3 group) greatly enhanced the weight gain rate and specific growth rate (SGR) of juvenile golden pompano, significantly upregulating growth-related factor expression in the brain and liver, as well as the levels of growth-related parameters in the serum. Polynomial regression analysis using SGR estimated the optimal dietary taurine level for golden pompano at 1.18%. Moderate exogenous taurine also increased the muscular thickness and villus length within the intestine, maintained intestinal physical barrier stability, activated the Nrf2/Keap-1/HO-1 signaling pathway, increased intestinal antioxidant enzyme gene expression and antioxidant enzyme activity in the serum, and upregulated immunoglobulin and complement levels in parallel with declining reactive oxygen species (ROS) levels in the serum. Antioxidant factor expression was also upregulated in the intestine. Furthermore, supplementation suppressed NF-κB signaling and intestinal pro-inflammatory cytokine gene expression, increased anti-inflammatory cytokine gene expression, and improved intestine immunity. Finally, taurine supplementation improved the survival rate of golden pompano challenged with S. agalactiae. Overall, our findings provide additional information and support for the rational use of taurine in healthy aquatic animal farming.

Effects of a commercial feed additive (Sanacore® GM ) on immune-antioxidant profile and resistance of gilthead seabream (Sparus aurata) against Vibrio alginolyticus infection

The effects of a functional additive (Sanacore® GM; SAN ) on immune and antioxidant indices, and the resistance of gilthead seabream (Sparus aurata) against Vibrio alginolyticus infection. For this, four diets containing 0% (the control), 0.1%, 0.2%, and 0.4% SAN were offered to triplicated groups of fish (20 - 23 g) for ten weeks. Subsequently, fish were injected intraperitoneally with V. alginolyticus and monitored for further ten days. Feeding the fish on SAN-supplemented diets showed positive effects on leukocyte counts and its differential percentages. Serum lysozyme activity and total immunoglobulin values, as well as phagocytic activity and indices, were linearly and quadratically higher in SAN-fed fish; especially at the 0.4% SAN diet. Similarly, linear and quadratic increases in catalase, superoxide dismutase, and total antioxidant capacity were observed in SAN-fed fish, particularly at the 0.4% SAN diet. Conversely, serum malondialdehyde values decreased in SAN-fed fish compared with the control group, which showed its highest value. The highest expression of the IL-1β gene coupled with the lowest TNF-α and HSP70 genes expressions was found in the fish fed with the 0.4% SAN. On the other hand, fish fed on the control diet showed the lowest IL-1β gene coupled with the highest TNF-α and HSP70 genes expressions. After bacterial infection, most of the control fish died with a relative percent of survival of 5.0%; meanwhile feeding gilthead seabream on SAN-enriched diets significantly enhanced their protection against V. alginolyticus infection. Fish fed on the 0.4% SAN diet showed 100% survival. The SAN administration to gilthead seabream especially at the 0.4% level led to significant promotions in antioxidative and immune responses and augment the fish resistance to V. alginolyticus infection.

Taurine alleviates endoplasmic reticulum stress, inflammatory cytokine expression and mitochondrial oxidative stress induced by high glucose in the muscle cells of olive flounder (Paralichthysolivaceus)

The aim of the present study was to evaluate the effects of taurine on endoplasmic reticulum stress, inflammatory cytokine expression and mitochondrial oxidative stress induced by high glucose in primary cultured muscle cells of olive flounder (Paralichthys olivaceus). Three experimental groups were designed as follows: muscle cells of olive flounder incubated with three kinds of medium containing 5 mM glucose (control), 33 mM glucose (HG) or 33 mM glucose + 10 mM taurine (HG + T), respectively. Results showed that taurine addition significantly alleviated the decreased activity of superoxide dismutase (SOD) and the ratio of reduced to oxidized glutathione (GSH/GSSG) induced by high glucose. The increase of cellular reactive oxygen species (ROS), malondialdehyde content and cell apoptosis induced by high glucose were alleviated by taurine. Besides, gene expression of glucose-regulated protein 78, PKR-like ER kinase, tumor necrosis factor-α, interleukin-6, interleukin-1β, interleukin-8, muscle atrophy F-box protein and muscle RING-finger protein 1 were significantly up-regulated in the HG group, and taurine addition decreased the expression of these genes. High glucose led to the swelling of the endoplasmic reticulum (ER). Meanwhile, the nuclear translocation of nuclear factor κB (NF-κB) and the release of cytochrome C from mitochondria induced by high glucose were suppressed by taurine addition. These results demonstrated that taurine alleviated ERS, inflammation and mitochondrial oxidative stress induced by high glucose in olive flounder muscle cells. The ROS production, NF-κB signaling pathway and mitochondria function were the main targets of the biological effects of taurine under high glucose condition.

A mixture of β-Glucan and Mannanoligosaccharide Ameliorated the Growth Rate, Digestive Enzyme Activity, Intestinal Morphometry, and Immunity of Common Carp (Cyprinus carpio)

The feasible strategies to keep up the growth and wellbeing of aquatic organisms by using beneficial dietary additives are highly recommended. Among these additives, β-glucan (BG) and mannanoligosaccharide (MOS) were examined on common carp performances in the current experiment. For 80 days, carps were fed four diets with 0%, 1%, 2%, and 3% BG/MOS (1:1) and distributed in four groups (triplicates). Higher final weight and weight gain (P<0.05) were detected in carps fed 1%, 2%, and 3% of BG/MOS than the control group. The feed conversion ratio showed lower values (P<0.05) in carps fed BG/MOS mixture at 2%, and 3% than 0% and 1% levels. The activities of amylase, lipase, and protease were higher in fish fed BG/MOS mixture than in the control group. Interestingly, fish fed BG/MOS mixture had markedly increased villi length and width with branched villi integrity. Further, the count of goblet cells was increased (P<0.05) in groups fed BG/MOS mixture than in carps fed the basal diet. The hemoglobin and hematocrit levels and the counts of red and white blood cells were higher in carps fed BG/MOS mixture than the control with the highest counts in 3% level. Additionally, the blood total protein, globulin, and phagocytic activity were higher (P<0.05) in groups that received BG/MOS mixture at 3% than the control. The lysozyme had a higher value in 1% group than the control (P<0.05). Therefore, using the mixture of BG/MOS at 2–3% is suggested for improving the growth rate, intestinal health, blood health, and immunity of common carp.

The influence of coconut oil on the growth, immune, and antioxidative responses and the intestinal digestive enzymes and histomorphometry features of Nile tilapia (Oreochromis niloticus)

The trials of finding non-conventional and alternative aquafeed ingredients are increasing. In this sense, this study evaluated the influence of coconut oil on the growth, feed utilization, immune, and antioxidative responses of Nile tilapia. Five test diets were formulated by mixing coconut oil with the other ingredients at 0, 1, 2, 3, and 4% of the total ration and presented for tilapia for 60 successive days. The final weight, SGR, weight gain (WG), and feed intake were superior in fish delivered 2% of coconut oil (P < 0.05). Concurrently, fish that received 2% coconut oil had lower FCR and higher PER than fish of the control and 4% groups (P < 0.05). Higher lipase activity was observed in fish of 2% and 3% levels than the remaining groups (P < 0.05). Besides, the amylase and protease activities of fish in 1%, 2%, and 3% groups were higher than the 0% level (P < 0.05). The total blood cholesterol, RBCs, and PCV showed higher values in Nile tilapia fed 2% and 3% coconut oil (P < 0.05). The lysozyme and phagocytic activities were higher in fish fed 2% and 3% levels than the control (P < 0.05), while the phagocytic index in 2% and 3% levels was higher than 0% and 4% levels. Furthermore, SOD and CAT were higher in fish fed 1%, 2%, and 3% than fish fed 0% and 4% levels while GSH was higher in fish of 1%, 2%, and 3% than fish fed 0% level (P < 0.05). However, the MDA level was markedly lower in fish fed 25, 3%, and 4% coconut oil than the 0% level (P < 0.05). The intestine's histological structure in all groups appeared normal, forming of intestinal villi projecting from the intestinal wall. Also, the structure of the hepatopancreas had a normal architecture in all groups. To sum up, the inclusion of coconut oil at 2 to 3% is recommended as a replacer for fish oil in Nile tilapia diets.

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.

Dietary Gracilaria persica mediated the growth performance, fillet colouration, and immune response of Persian sturgeon (Acipenser persicus)

Algal seaweeds have abundant amounts of active substances and can be used as pharmaceuticals and biomedicals in aquafeeds. In this context, the powder of red macroalgae Gracilaria persica was included in the diets of Persian sturgeon at the rate of 0, 2.5, 5, and 10 g/kg to investigate its role on the growth rate, fillet colouration, haemato-biochemical indices, serum, and skin mucus immunity. The weight gain, SGR, and FCR displayed no significant changes in fish fed varying levels of G. persica (P > 0.05). The level of total carotenoids was significantly higher in the blood and fillet of fish fed 5 and 10 g G. persica/kg diet (P < 0.05). Dietary G. persica significantly altered RBCs, WBCs, and HCT at 5, and 10 g/kg, whereas the Hb was increased in fish fed 5 g/kg (P < 0.05). The blood total protein and albumin were significantly increased in fish fed 5 and 10 g/kg (P < 0.05). No significant alterations were observed on ALT, AST, ALP, and glucose levels of fish fed varying levels of G. persica (P > 0.05). Serum Ig, lysozyme, superoxide dismutase, catalase, and respiratory burst activities were increased in fish fed 5, and 10 g/kg than fish fed 0 and 2.5 g/kg diet (P < 0.05). The level of total protein and lysozyme activity in the skin mucus were significantly higher in the blood and fillet of fish fed 5, and 10 g G. persica/kg diet than fish fed 0 and 2.5 g/kg (P < 0.05). Based on the obtained results, G. persica can be used as a feasible feed additive in the diets of Persian sturgeon at 5-10 g/kg diet.