Impacts of poultry by-product meal substituting fishmeal on growth efficiency, body composition, liver, and intestine morphology of European sea bass, Dicentrarchus labrax.

A twelve week feeding experiment was conducted to evaluate the replacement of fishmeal (FM) with poultry by-product meal (PBM) in practical diets for European sea bass, Dicentrarchus labrax with an average initial weight of 0.89 g. Five isocaloric (5.1 kcal lipid g-1) and isonitrogenous (451 g protein kg-1) diets were formulated with PBM replacing FM at levels of 0% (control), 25%, 50%, 75%, and 100%. The experiment was carried out in 30-in. nylon mesh net cages (hapas). At the termination of the trial, growth performance including final body weight, weight gain, specific growth rate, and protein growth rate of diets containing up to 75% PBM were comparable to those of the control group, whereas the diet with 100% PBM resulted in a significantly lower values (p < 0.05). Feed utilization exhibited variation among the treatments (p < 0.05). Whole body composition also showed significant differences across the dietary treatments. Essential amino acid (EAA) contents specifically arginine (Arg), histidine (His), methionine (Met), and threonine (Thr) in the whole body of fish fed diets with up to 50% PBM replacement were not significantly different from those in the control group. Furthermore, the intestinal microvilli length, width and absorption area increased significantly (p < 0.05) with PBM replacement levels up to 50%. Histological analysis of the liver revealed mild vacuolation of hepatocytes in fish fed up to 50% PBM,while pre-pancreatic fatty degeneration of hepatocytes was observed in fish fed diets with 75% and 100% PBM. Therefore, this study demonstrates that PBM can replace up to 50% of FM in the diets of European sea bass without adverse effects on growth performance, body composition, or liver and intestine morphology.

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.

Multi-functional application of octacosanol as a feed additive in animal and aquaculture: A review.

Demand for sustainable animal and aquaculture production drives the exploration of novel feed additives. We highlight octacosanol, a long-chain alcohol from plant sources, as a promising multifunctional feed additive. The review comprehensively evaluates octacosanol's applications in animal and aquaculture nutrition, including its molecular properties and mechanisms of action. It elucidates how octacosanol affects lipid metabolism, energy utilization and immune modulation. Octacosanol enhances livestock growth, efficiency, carcass quality and stress resilience. We thoroughly discuss how it enhances feed utilization, disease resistance and overall performance in finfish and shellfish in aquaculture. The review also addresses the ecological and sustainability aspects of octacosanol utilization. We identify challenges and knowledge gaps in octacosanol research, prompting suggestions for future investigations. We address regulatory considerations, dosage optimization and potential interactions with other feed additives to ensure the safe and effective use of octacosanol. In conclusion, the review highlights octacosanol's potential as a versatile feed additive in the animal and aquaculture industries and urges further research to uncover its benefits and sustainability contributions, proposing a prospective research plan for this purpose. This thorough analysis is a valuable resource for researchers, nutritionists and industry professionals looking to find innovative methods to improve production practices and advance sustainable food systems.

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.

Stevioside mitigates lead toxicity in thinlip mullet juveniles: Impacts on growth, metabolism, and immune function.

This study investigates the impact of varying concentrations of stevioside in the presence of lead (Pb) exposure on multiple aspects of thinlip mullet (Liza ramada) juveniles. Over 60 days, a total of 540 juvenile L. ramada with an initial weight of 3.5 ± 0.13 g were evenly distributed into six groups, each consisting of three replicates. The experimental diet consisted of varying levels of stevioside (150, 250, 350, and 450 mg/kg diet), with a consistent concentration of lead (Pb) set at 100 µg/kg diet. Stevioside demonstrated a positive influence on growth parameters, with the 450 mg/kg +Pb treatment showing the highest values. Biochemical parameters remained stable, but lead-exposed fish without stevioside displayed signs of potential liver damage and metabolic issues. Stevioside supplementation, especially at higher doses (≥250 mg/kg), reversed these negative effects, restoring biochemical markers to healthy control levels. Lead exposure significantly suppressed antioxidant enzyme activities, but co-administration of stevioside exhibited a dose-dependent protective effect, with 250, 350, and 450 mg/kg groups showing activities comparable to the healthy control. Lead-exposed fish without stevioside demonstrated attenuation of the immune response, but stevioside supplementation reversed these effects, particularly at ≥250 mg/kg. Stev (≥250 mg/kg) reduced IL-1ß and hepcidin expression, contrasting dose-dependent upregulation in lower dosages and lead-only group. Histological examinations of the intestine and liver supported these findings. In conclusion, stevioside, especially at 450 mg, positively impacted growth, biochemical parameters, antioxidant activity, immune response, and gene expression in L. ramada exposed to lead, suggesting its potential to mitigate lead toxicity in aquaculture. Additional research is warranted to investigate the long-term impacts of stevioside supplementation and its prospective implementation in aquaculture.

Effects of L-ascorbic acid on growth, non-specific immunity, antioxidant capacity, and intestinal and hepatopancreatic histology of red swamp crayfish, Procambarus clarkii.

This study investigated the dietary effects of coated L-ascorbic acid (LA) on growth, feed utilization, survival, serum biochemical indices, immunity, antioxidant capacity, and intestinal and hepatopancreatic histology of the pre-adult red swamp crayfish. Four isoproteinous and isolipidic diets were formulated to contain several LA levels as 0, 1300, 1600, and 1900 mg/kg and designated as control (LA0), LA13, LA16, and LA19, respectively. However, the analyzed LA concentrations in diets were 0.00, 199.57, 360.45, and 487.50 mg/kg in LA0, LA13, LA16, and LA19, respectively. Triplicate treatments of crayfish (21.60 ± 0.14 g) were fed the test diets and reared in fiberglass tanks with a density of 20 individuals per each for eight weeks. Results revealed that all LA treatments had significantly enhanced growth performance compared to the control. Of interest, the LA16 treatment recorded the highest final tank biomass, biomass gain, total feed intake, condition factor, and muscle yield among the other treatments. The tank feed conversion ratio was significantly decreased in LA treatments compared to the control. Moreover, dietary LA16 and LA19 had significantly higher survival rates (93.3%) compared to (85.0%) in the LA0 group. All dietary doses of LA significantly increased serum parameters (total protein, albumin, globulin, lysozyme activity) and respiratory burst activity compared to the LA0 treatment. Dietary LA16 significantly boosted the hepatopancreatic antioxidant capacity, manifested by decreased malondialdehyde concentrations, increased catalase, superoxide dismutase, and glutathione peroxidase enzyme activities, and reduced glutathione content compared to the LA-free diet. A normal histoarchitecture of the hepatopancreatic tubules was found in all LA treatments except with some minor degenerative changes in the tubular lumen, and hepatopancreatic cells associated with enlarged nuclei were found in the LA19. However, normal intestinal histoarchitecture was found in all treatments with no recorded intestinal lesions. Of interest, the polynomial regression performed on the analyzed LA concentrations suggested that 380 mg/kg would be suitable to provide maximal biomass gain for pre-adult crayfish. In conclusion, results revealed that coated LA could enhance the growth, immunity, and antioxidant capacity of pre-adult red swamp crayfish, suggesting its potential as a functional and necessary micronutrient for crayfish diets.

Effects of Different Aquafeed Sources on Growth Performance, Oxidative Capacity, and Fatty Acid Profile of Three Carps Reared in the Semi-Intensive Composite Culture System.

The current experiment is designed to evaluate the effect of different aquafeeds (farm-made versus commercial) on growth, body composition, oxidative capacity, and fatty acid profile in the semi-intensive composite culture system. For this, 1,100 fingerlings/acre having initial body weight and length, Labeo rohita (61.34 g, 171 mm), Catla catla (71.45 g, 181 mm), and Cyprinus carpio (30.80 g, 91 mm) were randomly distributed to 16 ponds and randomly fed on eight different diets (n = 2 pond/diet) in a completely randomized research design. Aquafeed were farm-based diets (D1-D2) and commercial aquafeed (D3-D8). The farm-made diets contained various crude protein levels of maize gluten (24.9%) and rice polish (7.3%), whereas commercial diets were procured from commercial feed plants (AMG, Supreme, Aqua, Star Floating, Hi-Pro, and Punjab feed). The growth performance of carps (L. rohita and C. catla) was significantly improved (p < 0.05) by feeding D3 as compared to other diets. Similarly, white blood cell concentration was greater (p < 0.05) in all species fed by D3 than in those fed on D7, D8, D5, D6, D1, and D2 fed groups, respectively. Alanine transaminase, aspartate transaminase, and alanine phosphatase activities were significantly lower (p < 0.05) in the D3-fed L. rohita, C. catla, and C. carpio compared with those fed on the rest of the treatments. The activities of glutathione peroxidase and superoxide dismutase were also higher (p < 0.05) for the D3 fed L. rohita, C. catla, and C. carpio than those fed on the rest diets. The groups fed on D3 and D4 had greater (p < 0.05) concentrations of myristic (14), palmitic acid (16), and stearic (18) acids than those fed on the rest of the commercial diets. However, meat chemical composition was similar (p > 0.05) across the treatments. These results also prove that the increase in the dietary protein level and lipid content can improve the fish's body's crude protein and fat levels. Feeding D3 improved the production performance, oxidative status, and fatty acid profile in composite major carps culture systems. Thus, based on growth, survival, and body composition, it is concluded that D3 and D4 may be recommended for a commercial culture of major carps. Dietary treatments had no significant impact (p > 0.05) on water's physical-chemical properties. Calcium content and alkalinity varied (p < 0.05), with D5 showing the lowest calcium and the highest alkalinity.

Dietary Wood and Activated Charcoal Improved Ammonium Removal, Heavy Metals Detoxification, Growth Performance, Blood Biochemistry, Carcass Traits, and Histopathology of European Seabass.

A 120-day growth trial was completed to assess rearing water quality and fish performance in terms of growth, feed efficacy, digestive enzymes, immunity, and antioxidant activity of seabass fed an experimental diet (ED) supplemented with commercial wood charcoal (WC) and activated wood charcoal (AC). Three levels (0, 10, and 20 g) of WC and AC were administered, representing five treatments: control (CD) fish-fed ED without additives, (WC-1) fish-fed ED containing 10 g kg-1 WC, (WC-2) fish-fed ED containing 20 g kg-1 WC, (AC-1) fish-fed ED containing 10 g kg-1 AC, and (AC-2) fish-fed ED containing 20 g kg-1 AC. Three hundred fish (60.12 ± 0.20 g/fish) were stocked in 15 cement tanks (4.0 m × 2.0 m × 1.2 m, water volume 5 m3 each) at 20 fish/tank and a daily feed ration of 3% of body weight. Results revealed significant improvements with increased growth variables (final weight, weight gain, and specific growth rate), decreased FCR, and decreased ammonia levels and heavy metals (Cu, Cd, Fe, Mn, and Zn) content in rearing water, muscle, and liver with fish fed WC and AC supplemented diets. Furthermore, considerable improvements in digestive enzymes, immunity, and antioxidant activity, with enhanced kidneys, liver, intestines, gills, and spleen. Fish fed the WC-1 diet had a higher final weight (171.90 g), better FCR (1.25), and improved internal organs than the other groups.

Neem leaf powder (Azadirachta indica) mitigates oxidative stress and pathological alterations triggered by lead toxicity in Nile tilapia (Oreochromis niloticus).

This study investigated the clinical and pathological symptoms of waterborne lead toxicity in wild Nile tilapia collected from a lead-contaminated area (the Mariotteya Canal: Pb = 0.6 ± 0.21 mg L-1) and a farmed fish after 2 weeks of experimental exposure to lead acetate (5-10 mg L-1) in addition to evaluating the efficacy of neem leaf powder (NLP) treatment in mitigating symptoms of lead toxicity. A total of 150 fish (20 ± 2 g) were alienated into five groups (30 fish/group with three replicates). G1 was assigned as a negative control without any treatments. Groups (2-5) were exposed to lead acetate for 2 weeks at a concentration of 5 mg L-1 (G2 and G3) or 10 mg L-1 (G4 and G5). During the lead exposure period, all groups were reared under the same conditions, while G3 and G5 were treated with 1 g L-1 NLP. Lead toxicity induced DNA fragmentation and lipid peroxidation and decreased the level of glutathione and expression of heme synthesis enzyme delta aminolaevulinic acid dehydratase (ALA-D) in wild tilapia, G2, and G4. NLP could alleviate the oxidative stress stimulated by lead in G3 and showed an insignificant effect in G5. The pathological findings, including epithelial hyperplasia in the gills, edema in the gills and muscles, degeneration and necrosis in the liver and muscle, and leukocytic infiltration in all organs, were directly correlated with lead concentration. Thus, the aqueous application of NLP at 1 g L-1 reduced oxidative stress and lowered the pathological alterations induced by lead toxicity.

Impacts of algae supplements (Arthrospira & Chlorella) on growth, nutrient variables, intestinal efficacy, and antioxidants in New Zealand white rabbits.

An 8-week trial to examine the impacts of Arthrospira platensis and Chlorella vulgaris on the growth, nutrient aspects, intestinal efficacy, and antioxidants of 75 New Zealand white male rabbits (initial body weight = 665.93 ± 15.18 g). Herein the study was designed in one-way ANOVA to compare the effects of the two algae species with two levels of supplementations in the feeds of New Zealand white rabbits. The rabbits were divided into five groups (n = 15/group), where the first group was allocated as the control group (Ctrl) while the second and third groups received A. platensis at 300 or 500 mg/kg diet (Ap300 or Ap500). The fourth and fifth groups fed C. vulgaris at 300 or 500 mg/kg diet (Ch300 or Ch500). The basal diet rabbits exhibited the lowest values of weight, lipase, protease, and the highest feed conversion ratio, which improved noticeably with algae addition, particularly with Ap500, Ch300, and Ch500. All tested groups showed normal intestinal structure. Amylase potency, hematological indicators, and serum biochemistry revealed non-significant variation except for a higher serum total protein and lower total cholesterol in algal groups. The best GPx existed in groups fed algal diets, while favorable SOD and CAT efficiency occurred at the higher level of Arthrospira and both levels of Chlorella. In conclusion, incorporating Arthrospira or Chlorella in the diet of New Zealand white rabbits improved performance, nutrient utilization, intestinal efficacy, and antioxidants. Arthrospira (Ap500) and Chlorella (Ch300 or Ch500) have almost the same beneficial effect on rabbit performance.

Ameliorative impacts of sodium humate on heat-stressed laying Japanese quail (Coturnix coturnix Japonica).

A total of 300 laying Japanese quails (230.10 ± 20 g body weight) divided into four groups (15 birds in 5 replicates/group) were used to examine the impacts of dietary sodium humate (SH) supplementation at levels of 0% (control diet), 0.2%, 0.4% and 0.6% on egg variables and physiological merits of laying quails for 10 weeks under heat stress conditions (15 June and 23 August 2021). Results showed 0.4% SH increased (p < 0.05) weight (12.27 vs. 11.91 g), production (79.84% vs. 69.20%), mass (597.13 vs. 510.48 g) and brokenness (2.8% vs. 5.4%) of eggs as compared to control. Egg shape, shell thickness, shell strength and cholesterol content as well as feed conversion ratio were higher (80.2, 295.8 µm, 1.468 kg/cm,2 11.08 mg/g and 2.69, p < 0.05) in 0.4% SH than in control group (75.2, 279.0 µm, 1.304 kg/cm,2  14.94 mg/g and 2.76). Feed intake, percentages of eggs' shells, yolk, albumen and serum biochemistry (total protein, albumin, AST and HDL) were not altered with the dietary SH. Birds fed on SH diets showed higher levels of globulin, calcium and phosphorus, as well as lower contents of albumin/globulin ratio, triglycerides, cholesterol, corticosterone compared with the control. Regression analysis of antioxidants expected higher total antioxidant capacity (TAC), superoxide dismutase, glutathione peroxidase at 0.35%, and glutathione at 0.40% SH, while the lowest concentration of malondialdehyde was computed at 0.45%. Similarly, immunoglobulins (IgG and IgM) maximum values were determined at 0.35% and 0.40% levels. Moreover, the concentration of tumour necrosis factor-alpha increased (p < 0.05) in all SH levels as compared to the control group. It is conceivable to conclude that the dietary implementation of SH at a level of 0.4% improved egg variables and well-being aspects of laying quail exposed to heat stress conditions.

Effect of Treating Eggs with Coenzyme Q10 (CoQ10) on Growth Variables, Histomorphometry, and Antioxidant Capacity in Red Tilapia (Oreochromis aureus × Oreochromis mossambicus) Larvae.

Red tilapia eggs one day post fertilization (dpf) were exposed to coenzyme Q10 (CoQ10) at rates of 0, 5, and 10 mg/L for control, treatment 2 (C5), and treatment 3 (C10), respectively, without exchanging water and until the larval mouth-opening stage. Fertilized eggs of red tilapia exposed to different concentrations of CoQ10 were hatched at rates (p > 0.05) between 38 to 54.67%. The yolk-sac diameter at the 2nd day post hatching (dph), ranged from 1.85 to 1.87 mm in depth and 1.63 to 1.88 mm in width and was not altered by the CoQ10 treatments. Similarly, red tilapia survival (p > 0.05) ranged from 22.67 to 32%. On 6 dph, a slight percentage (2.08%) of survived fishes exposed to high CoQ10 dose (C10) exhibited larval deformation in the form of an axial curvature of the spine in the abdominal and caudal region. Larvae displayed a normal structure of the esophagus folds in all fish groups, and larvae in the C5 group displayed the longest folds and widest muscularis layer, followed by fishes in the C10 group and the control. Red tilapia fry on 30 dph treated with CoQ10 possessed higher antioxidant potentials in terms of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) compared to the control. In conclusion, treating Red tilapia fertile eggs with 5 mg/L CoQ10 improves the growth, gut structure, and antioxidant efficiency of the produced larvae.

Exploring the Roles of Dietary Herbal Essential Oils in Aquaculture: A Review.

The aquaculture sector is one of the main activities contributing to food security for humanity around the globe. However, aquatic animals are susceptible to several farming stressors involved in deteriorated growth performance, reduced productivity, and eventually high mortality rates. In some countries still, antibiotics and chemotherapies are comprehensively applied to control biotic stressors. Aside from the apparent benefits, the continuous usage of antibiotics develops bacterial resistance, deteriorates bacterial populations, and accumulates these compounds in the aquatic environment. Alternatively, environmentally friendly additives were used to avoid the direct and indirect impacts on the aquatic ecosystem and human health. In aquaculture, medicinal herbs and extracts are extensively used and approved for their growth-promoting, anti-inflammatory, and antioxidative properties. Herbal essential oils contain many bioactive components with powerful antibacterial, antioxidative, and immunostimulant potentials, suggesting their application for aquatic animals. Essential oils can be provided via diet and can benefit aquatic animals by improving their well-being and health status. The use of essential oils in aquafeed has been studied in a variety of aquatic animals to determine their beneficial roles and optimum doses. The outputs illustrated that herbal essential oils are exciting alternatives to antibiotics with prominent growth promotion, antioxidative, and immunostimulant roles. Herein, we reviewed the beneficial roles of essential oils in aquaculture. This review also aims to describe trends in herbal essential oils use, mainly in commercial fish species, and to analyze different factors that affect essential oils' efficacy on the growth performance, antioxidative, and immune responses of finfish species.

Dietary Guduchi (Tinospora cordifolia) enhanced the growth performance, antioxidative capacity, immune response and ameliorated stress-related markers induced by hypoxia stress in Nile tilapia (Oreochromis niloticus).

Nile tilapia can tolerate a wide range of farming conditions; however, fluctuations in the environmental conditions may impair their health status. The incorporation of medicinal herbs in aquafeed is suggested to overcome stressful conditions. In this study, dietary Guduchi (Tinospora cordifolia) was evaluated on the growth performance, antioxidative capacity, immune response, and resistance of Nile tilapia against hypoxia stress. Fish fed five diets incorporated with Guduchi at 0, 2, 4, 6, and 8 g/kg for 56 days then exposed with hypoxia stress for 72 h. The growth performance, feed intake, and feed efficiency ratio were significantly (P < 0.05) increased by including Guduchi in tilapia diets regardless of the inclusion level. Similarly, the lipase and protease activities were markedly (P < 0.05) increased in tilapia fed dietary Guduchi. The activities of lysozyme and bactericidal activities in serum and mucus, nitro-blue tetrazolium (NBT), and alternative complement activity (ACH50) were markedly (P < 0.05) enhanced in tilapia treated with Guduchi supplements regardless of the dose. Additionally, the activities of liver and intestinal superoxide dismutase, catalase, and glutathione peroxidase were markedly enhanced (P < 0.05) by including Guduchi in tilapia diets compared with the control. Before and after hypoxia stress, tilapia-fed dietary Guduchi had lower glucose and cortisol levels than fish-fed Guduchi-free diets (P < 0.05). In all groups, glucose and cortisol levels were markedly higher after hypoxia compared before hypoxia stress (P < 0.05). In conclusion, dietary Guduchi can be included at 5.17-5.49 g/kg to enhance the growth performance, digestive enzyme activity, immune and antioxidative responses, and the resistance of Nile tilapia against hypoxia stress.

Impacts of different antioxidants sources on semen quality and sperm fertilizing ability of Muscovy ducks under high ambient temperature.

The potentiality of coenzyme Q10 (CoQ10), D-Aspartic acids (D-Asp), Maca or vitamin C, as antioxidant agents, to reduce negative impacts of high ambient temperature on semen quality, oxidative capacity and fertility of Muscovy ducks was investigated. Seventy-five Muscovy males (34-wk of age) were distributed randomly into five experimental groups of fifteen ducks each. The first group was fed a basal diet without supplementation and served as a control. The other four groups were fed a basal diet supplemented with 400 mg CoQ10, 400 mg D-Asp, 500 mg Maca and 200 mg vitamin C (ascorbic acid) per kg diet for 17 consecutive weeks under high ambient temperature conditions. The dietary inclusion of antioxidants significantly maintains better semen variables and a higher fertility rate either for fresh or preserved semen. Among the tested antioxidants, the Maca group showed the best status and outperformed the others in terms of motility, viability, sperm cell concentration, intact acrosome and membrane integrity percentages, total proteins, total antioxidants capacity, glutathione peroxidase, superoxide dismutase (SOD), malondialdehyde (MDA), testosterone, and the fertility rate for the fresh semen, as well as, forward motility, SOD and MDA for the preserved semen. The CoQ10 showed similar results to Maca in some measurements. Conversely, the basal diet had the poorest performance in all examined variables. The dietary incorporation of antioxidants (Maca or CoQ10) enhances fresh and preserved semen quantity and quality, as well as the fertility rate of Muscovy males under high ambient temperature conditions.

Dietary Synbiotics Can Help Relieve the Impacts of Deltamethrin Toxicity of Nile Tilapia Reared at Low Temperatures.

The optimal water temperature for the normal growth of Nile tilapia is between 26 and 28 °C, and the toxicity of pesticides is strongly related to water temperature. An alternate approach to augmenting the resistance of fish to ambient water toxicity and low water temperature via synbiotic feeding was proposed. In this study, fish were allocated into four groups with 10 fish in each replicate, where they were fed a basal diet or synbiotics (550 mg/kg) and kept at a suboptimal water temperature (21 ± 2 °C). The prepared diets were fed to Nile tilapia for 30 days with or without deltamethrin (DMT) ambient exposure (15 µg/L). The groups were named control (basal diet without DMT toxicity), DMT (basal diet with DMT toxicity), synbiotic (synbiotics without DMT toxicity), and DMT + synbiotic (synbiotics with DMT toxicity). The results displayed upregulated transcription of catalase, glutathione peroxidase, and interferon (IFN-γ) genes caused by DMT exposure and synbiotic feeding when compared with the controls. Moreover, HSP70 and CASP3 genes displayed increased transcription caused by DMT exposure without synbiotic feeding. However, fish fed with synbiotics showed downregulated HSP70 and CASP3 gene expressions. The transcription of IL-1ß and IL-8 genes were also decreased by DMT exposure, while fish fed synbiotics showed upregulated levels. DMT exposure resulted in irregular histopathological features in gills, intestine, spleen, and liver tissues, while fish fed synbiotics showed regular, normal, and protected histopathological images. Our results indicated that dietary synbiotics ameliorated histopathological damages in DMT-exposed tilapia through alleviation of oxidative stress and inflammation as well as enhancing the immunity.

Dietary probiotics as a strategy for improving growth performance, intestinal efficacy, immunity, and antioxidant capacity of white Pekin ducks fed with different levels of CP.

The potential impacts of probiotics on the performance and health status of white Pekin ducks fed with optimal or suboptimal dietary CP were evaluated during the growing period. A total of 180 male white Pekin ducks (14-day-old ducks with an initial weight of 415.65 ± 2.20 g) were randomly divided into 4 experimental groups (45 in each group of 5 replicates) in a 2 × 2 factorial design. The main factors included 2 dietary CP levels (18 or 14%) and dietary probiotic addition (with or without probiotics). The probiotic source was supplemented at 0.2 g per kilogram of diet from a blend of Lactobacillus acidophilus and Lactobacillus casei. The results showed that the diet containing 18% CP and probiotics significantly increases the final and total weight gain. Activities of intestinal enzymes (amylase, lipase, and protease), morphometrics (villus length, goblet cell count, and cryptal depth), and carcass percentage were also increased significantly. Total protein content, lysozyme activity, bactericidal activity, nitro blue tetrazolium levels, alternative complement pathway, superoxide dismutase activity, and catalase activity were significantly increased, whereas glucose, cortisol, and total cholesterol levels were decreased when treated with diet containing 18% CP and probiotics. Conversely, the group treated with diet containing 14% CP without probiotics showed the poorest performance, carcass properties, immune response, and antioxidant potential. In conclusion, probiotic addition to the 14% CP diet improved the performance of white Pekin ducks caused by reduced CP diet to performance due to the 18% CP diet without probiotic supplementation.

Antiparasitic and Antibacterial Functionality of Essential Oils: An Alternative Approach for Sustainable Aquaculture.

Using synthetic antibiotics/chemicals for infectious bacterial pathogens and parasitic disease control causes beneficial microbial killing, produces multi-drug resistant pathogens, and residual antibiotic impacts in humans are the major threats to aquaculture sustainability. Applications of herbal products to combat microbial and parasitic diseases are considered as alternative approaches for sustainable aquaculture. Essential oils (EOs) are the secondary metabolites of medicinal plants that possess bioactive compounds like terpens, terpenoids, phenylpropenes, and isothiocyanates with synergistic relationship among these compounds. The hydrophobic compounds of EOs can penetrate the bacterial and parasitic cells and cause cell deformities and organelles dysfunctions. Dietary supplementation of EOs also modulate growth, immunity, and infectious disease resistance in aquatic organisms. Published research reports also demonstrated EOs effectiveness against Ichthyophthirius multifiliis, Gyrodactylus sp., Euclinostomum heterostomum, and other parasites both in vivo and in vitro. Moreover, different infectious fish pathogenic bacteria like Aeromonas salmonicida, Vibrio harveyi, and Streptococcus agalactiae destruction was confirmed by plant originated EOs. However, no research was conducted to confirm the mechanism of action or pathway identification of EOs to combat aquatic parasites and disease-causing microbes. This review aims to explore the effectiveness of EOs against fish parasites and pathogenic bacteria as an environment-friendly phytotherapeutic in the aquaculture industry. Moreover, research gaps and future approaches to use EOs for sustainable aquaculture practice are also postulated.

The growth performance, antioxidant capacity, immunological responses, and the resistance against Aeromonas hydrophila in Nile tilapia (Oreochromis niloticus) fed Pistacia vera hulls derived polysaccharide.

The present study aimed at evaluating the supplementation of dietary Pistacia vera hulls derived polysaccharide (PHDP) at varying levels (0, 2.5, 5, and 10 g/kg diet) on the growth rate, digestive enzyme activity, immune response, and antioxidative capacity of Nile tilapia. After the feeding trial (60 days), fish were injected intraperitoneally with Aeromonas hydrophila, and the cumulative mortality was calculated for 10 days. The final body weight, weight gain, specific growth rate, survival rate, amylase activity, red blood cells, hemoglobin, serum total protein, and serum lysozyme activity (LZM) were significantly higher in fish fed PHDP at 5 and 10 g/kg than fish fed 0 and 2.5 g/kg diet (P ≤ 0.05). However, the feed conversion ratio and glucose levels were significantly decreased by 5 and 10 g PHDP/kg diet. Further, the protease digestive activity, serum alkaline phosphatase, and serum alternative complement (ACH50) had higher values in fish fed 5 g PHDP/kg diet than tilapia fed 0 g PHDP/kg diet (P ≤ 0.05). The serum protease and immunoglobulin (Ig) presented the highest values in fish fed 10 g PHDP/kg diet followed by fish fed 5 g PHDP/kg diet (P ≤ 0.05). The LZM, ACH50, and Ig in the mucus samples were significantly higher in fish fed 5 or 10 g PHDP/kg diet than fish fed 0 g PHDP/kg diet (P ≤ 0.05). The levels of superoxide dismutase and catalase in the liver tissue was significantly higher in fish fed 5 or 10 g PHDP/kg diet than fish fed 2.5 g PHDP/kg diet (P ≤ 0.05). On the other hand, malondialdehyde concentration was significantly lower in tilapia fed 5 and 10 g PHDP/kg diet than tilapia fed 0 and 2.5 g PHDP/kg diet (P ≤ 0.05). The lowest mortality rate and the highest relative percentage survival were in fish fed 5 g/kg followed by 10 g level after 10 days of A. hydrophila injection. Accordingly, dietary PHDP at 5-10 g/kg is recommended to improve the growth performance, antioxidative capacity, immune response, and resistance against A. hydrophila in Nile tilapia.

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.