Bee venom enhances performance and immune function in thinlip mullet: A promising approach for sustainable aquaculture.

As an environmentally friendly alternative to antibiotics, bee venom holds promise for aquaculture due to its diverse health advantages, including immune-amplifying and anti-inflammatory features. This study investigated the effects of dietary bee venom (BV) on the growth and physiological performance of Thinlip mullet (Liza ramada) with an initial body weight of 40.04 ± 0.11 g for 60 days. Fish were distributed to five dietary treatments (0, 2, 4, 6, and 8 mg BV/kg diet) with three replicates. Growth traits, gut enzyme ability (lipase, protease, amylase), intestinal and liver histology, blood biochemistry, immune responses [lysozyme activity (LYZ), bactericidal activity (BA), nitroblue tetrazolium (NBT%)], and antioxidant status [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), malondialdehyde (MDA)] were evaluated. BV supplementation significantly improved growth performance, digestive enzyme activity, histological integrity of organs, immune responses (LYZ, BA), and antioxidant status (SOD, CAT, GPx), while declining MDA levels. Optimal BV levels were identified between 4.2 and 5.8 mg/kg diet for different parameters. Overall, the findings suggest that BV supplementation can enhance growth and physiological performance in Thinlip mullet, highlighting its potential as a beneficial dietary supplement for fish health and aquaculture management.

Comparative impact of replacing fish meal with azolla on growth, water quality, and physiology of red tilapia fingerlings at varying salinities.

A 210-day experiment to assess the efficacy of substituting azolla plant powder at levels of 0, 20, 40, and 60% for fish meal on red tilapia fingerlings (RTF, initial weight of 18.23 ± 0.12 g) performance under salinity levels of 5, 18, and 28ppt. Among the various conditions, RTF-fed 20% azolla at 28 and 5ppt salinity showcased the highest specific growth rate (SGR), whereas the lowest SGR was observed in fish-fed 60% azolla at 5ppt salinity. Upon azolla incorporation, noteworthy elevations in phytoplankton, zooplankton, dissolved oxygen (DO), pH, NH3, and NO3 were noted and conversely, azolla introduction led to decreased NH4 and NO2 concentrations in all salinity levels. Further, a significant (p < 0.05) interaction between azolla levels and water salinity (S×A) significantly impacted the hematological parameters of RTF. The highest levels of superoxide dismutase (SOD), catalase (CAT), and total protein (TP) were found in RTF-fed 20% azolla at 28ppt salinity, while the lowest CAT and TP levels occurred in RTF-fed 60% azolla at 5ppt salinity. The highest aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were recorded in the RTF group fed 60% azolla at 5ppt salinity, with the lowest values seen in the group given 20% azolla at 28ppt salinity. RTF fed a 20% azolla diet at 18ppt salinity exhibited the highest lysozyme value, in contrast to the lowest value observed in the RTF group fed the control diet at 18ppt salinity. In conclusion, this study recommends the utilization of azolla at inclusion levels ranging from 20 to 40%, as it has the potential to notably enhance the immune system and elevate the survival rate of RTF.

Growth Performance, Growth-Related Genes, Digestibility, Digestive Enzyme Activity, Immune and Stress Responses of de novo Camelina Meal in Diets of Red Seabream (Pagrus major).

A 60-day experiment was designed to assess the effect of different ratios of fish meal (FM): camelina meal plant protein (CM) on growth response and relative gene expression of growth-promoting factors, feed utilization potency, digestive enzymes activities, apparent digestibility (ADC), stress response, non-specific immunity of Pagrus major. Four isonitrogenous (490.7 g/kg of crude protein) and isolipidic (91.5 g/kg total lipid) experimental diets were formulated and designated as camelina meal (CM0), soyabean meal (SBM20.5), CM20.5, and CM33 based on protein contents. At the end of the feed trial, significantly higher (p < 0.05) weight gain, specific growth rate, and feed intake but lower feed conversion ratio were recorded in fish fed CM0, SBM20.5, and CM20.5 than fish fed CM33. The lowest growth, feed utilization, enzyme activity, and digestibility were recorded in fish fed CM33. Significantly higher pepsin, amylase, and protease activities were observed in fish fed CM0, SBM20.5, and CM20.5 diets than fish fed CM33. The highest ADC of protein was recorded in fish fed CM0, SBM20.5, and CM20.5 diets. Hematocrit levels were depressed CM33 while total serum protein, total cholesterol, triglyceride, blood urea nitrogen, total bilirubin, aspartate aminotransferase, and alanine aminotransferase were not significantly changed by the inclusion of CM. Non-specific immune variables (lysozyme activity, peroxidase activity in serum and nitro blue tetrazolium) in fish fed CM0, SBM20.5, and CM20.5 were significantly higher than in fish fed CM33 diet. The superoxide dismutase of fish fed CM20.5 was not significantly different from CM0 and SBM20.5 (p > 0.05). Catalase and low salinity stress test show that CM0, SBM20.5, and CM20.5 were not significantly (p > 0.05) different, while CM33 was significantly lower than the rest of the diets. TBARs show that CM20.5 and CM33 diets were significantly different (p < 0.05), but CM20.5 was not significantly different from SBM20.5. Significantly higher hepatic IGF-1 and IGF-2 mRNA expression was found in fish-fed diet groups CM0, SBM20.5, and CM20.5 than fish fed CM33. The present study indicated that the addition of CM up 205 kg/kg to diet maintains growth, digestive enzymes, nutrient digestibility, immunity, stress resistance, and feed utilization efficiency of red sea bream.

Effect of Substituting Fish Oil with Camelina Oil on Growth Performance, Fatty Acid Profile, Digestibility, Liver Histology, and Antioxidative Status of Red Seabream (Pagrus major).

A 56-day feeding trial to evaluate the responses of red seabream (initial weight: 1.8 ± 0.02 g) to the substitution of fish oil (FO) with camelina oil (CO) at different ratios was conducted. The control diet formulated at 46% CP (6F0C) contained only FO without CO; from the second to the fifth diet, the FO was substituted with CO at rates of 5:1 (5F1C), 4:2 (4F2C), 3:3 (3F3C), 2:4 (2F4C), and 0:6 (0F6C). The results of the present study showed that up to full substitution of FO with CO showed no significant effect on growth variables BW = 26.2 g-28.3 g), body weight gain (BWG = 1275.5-1365.3%), specific growth rate (SGR = 4.6-4.7), feed intake (FI = 25.6-27.8), feed conversion ratio (FCR = 1.0-1.1), biometric indices condition factor (CF = 2.2-2.4), hepatosomatic index (HSI = 0.9-1.1), viscerasomatic index (VSI = 7.5-9.5), and survival rates (SR = 82.2-100) with different FO substitution levels with CO. Similarly, there were no significant differences (p < 0.05) found in the whole-body composition except for the crude lipid content, and the highest value was observed in the control group (291 g/kg) compared to the other groups FO5CO1 (232 k/kg), FO4CO2 (212 g/kg), FO2CO4 (232 g/kg) and FO0CO6 (244 g/kg). Blood chemistry levels were not influenced in response to test diets: hematocrit (36-33%), glucose (Glu = 78.3-71.3 mg/dL), total protein (T-pro = 3.1-3.8 g/dL), total cholesterol (T-Chol = 196.0-241 mg/dL), blood urea nitrogen (BUN = 9.0-14.6 mg/dL), total bilirubin (T-Bil = 0.4-0.5 mg/dL), triglyceride (TG = 393.3-497.6 mg/dL), alanine aminotransferase test (ALT = 50-65.5 UL/L), aspartate aminotransferase test (AST = 38-69.3 UL/L). A remarkable modulation was observed in catalase (CAT) and superoxide dismutase (SOD) activities in the liver, as CAT and SOD values were lower with the complete FO substitution with CO (0F6C), and the highest values were observed in the control and (4F2C). This study indicates that red seabream may have the ability to maintain LC-PUFAs between tissues and diets, and CO substitution of FO could improve both lipid metabolism and oxidation resistance as well as maintain digestibility. In conclusion, dietary FO can be replaced up to 100% or 95% by CO in the diets of red seabream as long as n-3 HUFA, EPA, and DHA are incorporated at the recommended level.

Assessing the effectiveness of CoQ10 dietary supplementation on growth performance, digestive enzymes, blood health, immune response, and oxidative-related genes expression of Nile tilapia (Oreochromis niloticus).

The present study was conducted to investigate the effects of CoQ10 dietary supplementation on growth performance, feed utilization, blood profile, immune response, and oxidative status of Nile tilapia (12.4 ± 0.11 g, initial body weight). Five experimental diets were formulated containing CoQ10 at levels of 0, 10, 20, 30, 40 mg kg-1 diet (D1, D2, D3, D4, and D5, respectively). The results of a 56-days feeding trial showed that, significantly higher weight gain % (WG %), specific growth rate (SGR), feed intake (FI), and feed efficiency ratio (FER) were recorded in fish groups fed diets supplemented with different levels of CoQ10 than fish fed the control diet, while survival rate (SR%), condition factor (CF), hepatosomatic index (HSI) and viscerasomatic index (VSI) showed no obvious differences (P > 0.05) among all experimental groups. The highest activities of digestive enzymes (protease, amylase, and lipase) were recorded in D3, D4, and D5 groups. Moreover, blood status of all experimental fish was within normal rates and significant alterations were only in the case of glucose, cortisol, total cholesterol (T-Chol), triglycerides, and total protein (TP), where fish fed on D3, D4 and D5 diets exhibited lower values of glucose, cortisol, T-Chol, and triglycerides and higher values of TP. Furthermore, the lowest values of immune response [lysozyme, bactericidal, respiratory burst (NBT), and alternative complement pathway activities (ACP)], antioxidant capacity and oxidative related genes expressions [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)] resulted from feeding on the basal diet (D1) compared to CoQ10 diets, especially with its high levels {≥20 mg kg-1 diet (D3, D4, and D5)} in most cases. In conclusion, our results suggest that the use of ≥20 mg CoQ10 kg-1 diet improves the growth and health being of Nile tilapia.

Influence of dietary inosine and vitamin C supplementation on growth, blood chemistry, oxidative stress, innate and adaptive immune responses of red sea bream, Pagrus major juvenile.

Both inosine (INO) and vitamin C (l-ascorbic acid, AsA) play important roles in growth performance, feed utilization and health status of fish. Therefore, a 56 days feeding trial was conducted to determine the interactive effects of dietary INO and AsA on growth performance, oxidative status, innate and adaptive immune responses of red sea bream. Fish growth performance and fed utilization parameters were significantly affected by dietary INO supplementation but not by AsA. Fish fed diets with INO at 4 g kg-1 diet in combination of high and low levels of AsA (3.1 g kg-1 and 9.3 g kg-1) produced the highest growth and feed utilization performances. In terms of growth and feed utilization performances no significant interaction effects were observed between INO and AsA. Dietary INO significantly influenced hematocrit, glucose and glutamyl oxaloacetic transaminase (GOT) content of red sea bream meanwhile AsA also significantly influenced hematocrit, glucose, total cholesterol, blood urea nitrogen (BUN) and glutamic-pyruvate transaminase (GPT) content of the test fish. No significant interaction effects was also observed between INO and AsA on measured hematological parameters. Reactive oxygen metabolites (d-ROMs) significantly influenced by both INO and AsA. Fish fed diet groups D1, D4 and D6 showed best oxidative stress resistance. Only INO was a significant factor on nitro-blue-tetrazolium activity (NBT) and bactericidal activity (BA). Neither INO nor AsA was a significant factor on serum catalase activity (CAT), total serum protein (TSP), peroxidase activity (PA) and lysozyme activity (LA). No significant interaction effects was observed between INO and AsA on measured innate immune parameters. Agglutination antibody titer was significantly influenced by dietary supplementation, after 15 days of vaccination but not in 21 days. In the day 15th fish and diet group D3 and D5 showed significantly higher values compared to diet groups control and D1. INO was the only significant factor of increasing agglutination antibody titer in 15 t h day. While AsA was not a significant factor on agglutination antibody titer values in day 15 t h, there was an interaction between dietary INO and AsA levels. Finally under the experimental conditions, fish fed high INO and low AsA levels (4 g kg-1 and 0.31 g kg-1 diet, respectively) showed best growth and feed utilization performance. Simultaneously, low level of INO and high level of AsA (2 g kg-1 and 0.93 g kg-1 diet, respectively) improved blood chemistry and immunological parameters. Furthermore, combined use of INO and AsA is possible to improve hemato-immunological responses of red sea bream.

Bacillus subtilis as probiotic candidate for red sea bream: Growth performance, oxidative status, and immune response traits.

The effects of dietary administration of Bacillus subtilis on the growth, digestive enzyme activity, blood chemistry, oxidative status and immune response of red sea bream (Pagrus major) were evaluated in the current study. Fish fed five different levels of B. subtilis at 0 (BS0), 1 × 104 (BS1), 1 × 106 (BS2), 1 × 108 (BS3) and 1 × 1010 (BS4) CFU kg-1 diet for 60 days. The obtained results showed that B. subtilis supplementation significantly improved growth performance (FBW, WG and SGR), feed utilization (FI, FCE, PER and PG) and whole-body protein content when compared to the control group (P < 0.05). Furthermore, the specific activities of amylase, protease and lipase enzymes up regulated significantly upon B. subtilis incorporation in red sea bream diets (P < 0.05). No changes have been reported on blood biochemical variables except for the plasma total protein, which increased significantly in fish fed BS3 diet when compared with the control diet (P < 0.05). Hematocrit, hemoglobin and the nitro blue tetrazolium values also reported the highest values significantly in fish fed B. subtilis, especially in case of BS3 and BS4 diets (P < 0.05). Serum bactericidal activity enhanced significantly in BS2, BS3 and BS4 groups (P < 0.05), while mucus bactericidal activity showed no significant activity among tested groups (P > 0.05). Serum lysozyme activity exhibited higher values in case of BS3 and BS4 groups than BS0 group (P < 0.05), while mucus lysozyme activity increased only in BS3 group. Also, serum peroxidase activity enhanced significantly in fish fed BS2 and BS3 diets (P < 0.05), however, no activities were observed in the collected mucus. All groups reflexed high tolerance ability against oxidative stress except for BS0 and BS1 groups. Additionally, catalase activity increased significantly in all B. subtilis fed groups when compared to BS0 group (P < 0.05). Considering the obtained results, the supplementation of B. subtilis in the diet of red sea bream at 1 × 108 and 1 × 1010 CFU kg-1 diet could improve the growth, feed utilization, health condition and immune response.

Growth performance, blood health, antioxidant status and immune response in red sea bream (Pagrus major) fed Aspergillus oryzae fermented rapeseed meal (RM-Koji).

This study evaluated the effects of dietary substitution of fishmeal by graded levels of a blend composed of Aspergillus oryzae fermented rapeseed meal [0% (RM0), 25% (RM25), 50% (RM50), 75% (RM75) and 100% (RM100)] on growth performance, haemato-immunological responses and antioxidative status of Pagrus major (average weight 5.5 ±â€¯0.02 g). After 56 days, growth performances were significantly improved in fish fed RM25 diet compared to control (P < 0.05). Meanwhile, up to 50% replacement of fishmeal did not affect growth performance, feed conversion efficiency, protein efficiency ratio, protein apparent digestibility, protease activity, fish somatic indices and survival compared to control. While blood hematocrit and plasma protein were significantly enhanced in groups fed RM0 and RM25 diets, most of the hematological parameters did not change through the trial except glutamic pyruvate transaminase which was significantly increased in RM75 and RM100 groups and blood cholesterol which was gradually decreased with the increasing level of the blend. Interestingly, feeding fish with RM25 and RM50 diets significantly showed enhanced lysozyme, bactericidal and peroxidase activities and fish fed the same diets showed high resistance against oxidative stress (biological antioxidant potential and reactive oxygen metabolites). Additionally, catalase activity and tolerance against low salinity seawater were higher in fish fed RM25 diet. These findings suggested that, at a moderate level (25% and 50%), substitution of fishmeal by the fermented rapeseed meal promoted growth, nutrient utilization, and exerted immune responses and anti-oxidative effects in red sea bream.

Effects of dietary supplementation of Lactobacillus rhamnosus or/and Lactococcus lactis on the growth, gut microbiota and immune responses of red sea bream, Pagrus major.

Pagrus major fingerlings (3·29 ± 0·02 g) were fed with basal diet (control) supplemented with Lactobacillus rhamnosus (LR), Lactococcus lactis (LL), and L. rhamnosus + L. lactis (LR + LL) at 10(6) cell g(-1) feed for 56 days. Feeding a mixture of LR and LL significantly increased feed utilization (FER and PER), intestine lactic acid bacteria (LAB) count, plasma total protein, alternative complement pathway (ACP), peroxidase, and mucus secretion compared with the other groups (P < 0.05). Serum lysozyme activity (LZY) significantly increased in LR + LL when compared with the control group. Additionally, fish fed the LR + LL diet showed a higher growth performance (Fn wt, WG, and SGR) and protein digestibility than the groups fed an individual LR or the control diet. Superoxide dismutase (SOD) significantly increased in LR and LR + LL groups when compared with the other groups. Moreover, the fish fed LR or LL had better improvement (P < 0.05) in growth, feed utilization, body protein and lipid contents, digestibility coefficients (dry matter, protein, and lipid), protease activity, total intestine and LAB counts, hematocrit, total plasma protein, biological antioxidant potential, ACP, serum and mucus LZY and bactericidal activities, peroxidase, SOD, and mucus secretion than the control group. Interestingly, fish fed diets with LR + LL showed significantly lower total cholesterol and triglycerides when compared with the other groups (P < 0.05). These data strongly suggest that a mixture of LR and LL probiotics may serve as a healthy immunostimulating feed additive in red sea bream aquaculture.