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.

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.

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 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.

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.