Fungicidal synergistic effect of biogenically synthesized zinc oxide and copper oxide nanoparticles against Alternaria citri causing citrus black rot disease

Citrus black rot disease being caused by Alternaria citri is a major disease of citrus plants with 30–35% economic loss annually. Fungicides had not been effective in the control of this disease during last few decades. In the present study, antifungal role of green synthesized zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) were studied against Alternaria citri. Alternaria citri was isolated from disease fruits samples and was identified by staining with lacto phenol cotton blue. Furthermore, CuO and ZnO NPs were synthesized by utilizing the lemon peels extract as the reducing and capping agent. Nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. From the XRD data, the calculated size of CuO NPs was to be 18 nm and ZnO NPs was16.8 nm using Scherrer equation. The SEM analyses revealed the surface morphology of all the metal oxide NPs synthesized were rounded, elongated and or spherical in the shape. The zone of inhibition was observed to be 50 ± 0.5 mm by CuO NPs, followed by 51.5 ± 0.5 mm by ZnO NPs and maximum zone of antifungal inhibition was observed to be 53 ± 0.6 mm by mix metal oxide NPs. The results of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the synthesized nanoparticles showed that at the certain concentrations (80 mg ml^?1), these NPs were capable of inhibiting the fungal growth, whereas above that specified concentrations (100 mg ml^?1), NPs completely inhibited the fungal growth. Based on these findings, the green synthesized NPs can be used as alternative to fungicide in order to control the citrus black rot disease.     

Assessment the using of silica nanoparticles (SiO2NPs) biosynthesized from rice husks by Trichoderma harzianum MF780864 as water lead adsorbent for immune status of Nile tilapia (Oreochromis niloticus)

Rice husks (RHs) was used as a substrate for biosynthesis of high-value Silica nanoparticles (SiO₂NPs). An isolate of Trichoderma harzianum MF780864 (T. harzianum) was isolated and identified based on the Internal Transcribed Spacers (ITS) sequences; it showed the potentiality to induce SiO₂NPs in the process of RHs biotransformation. SiO₂NPs were produced extracellularly and their size was of about 89 nm. SiO₂NPs characterized by oval, rod and cubical particles by using Transmission Electron Microscope (TEM).The Fourier transform infrared spectroscopy (FTIR) confirmed the presence of various functional groups of biomolecules and capping protein, encapsulating SiO₂NPs. Water and fish samples were collected from private fish farms in El-Sharkia Governorate, Egypt. Lead (Pb) was detected from water and fish samples at its highest concentration at about 0.088 mg/L. The adsorption capacity of Pb by SiO₂NPs was evaluated by testing different concentrations of SiO₂NPs viz. 1, 2, and 3 mg/L, wherein 1 mg/L revealed the highest Pb adsorption efficiency. Within laboratory trials, the results indicated that highest Pb adsorption efficiency revealed through the increasing of SiO₂NPs concentrations until 120 h. In vivo trial that lasted for 8 weeks, Nile tilapia (Oreochromis niloticus) (29.78 ± 0.36 g body weight) supplemented with 0.088 mg/L Pb was divided into four experimental groups having three replicates (15 fish/replicate; 45 fish/group). The results showed that SiO₂NPs supplementation through water revealed significant increase in growth and hematological parameters of O. niloticus. Moreover, enhancement of antioxidant capacity (TAC), and immune related gene expression of IL-1β were increased in the presence of SiO₂NPs compared with the groups of Pb exposure. Moreover, Pb residue level in fish muscles was noticeably decreased in the SiO₂NPs treated groups. Thus, this research opens up other possibilities in the field of using SiO₂NPs as a lead adsorbent for water bioremediation.     

Effect of dietary fish meal replacement by red algae, Gracilaria arcuata, on growth performance and body composition of Nile tilapia Oreochromis niloticus

A 12-week long feeding experiment was initiated to evaluate the effect of dietary supplementation of red algae, Gracilaria arcuata, on the growth performance, feed utilization and body composition of Nile tilapia Oreochromis niloticus (Linnaeus, 1758). The fish were fed with an algae-free control diet (C) and three experimental diets which replaced conventional fish meal with varying levels of dried G. arcuata (20%, 40% and 60%, represented as G20, G40 and G60, respectively). The growth parameters of final weight (FW), weight gain (WG), percentage of weight gain (WG%), daily growth rate (DGR) and specific growth rate (SGR) were significantly reduced (P < 0.05) at all levels of algae incorporation compared to the control diet. Moreover, the negative impact of Gracilaria meal on the growth performance of Nile tilapia increased as the proportion of algae in the diet increased, with fish on diet G20 exhibiting a significantly higher growth performance than the fish on either of the G40 and G60 diets. On the other hand, the feed utilization parameters feed conversion ratio (FCR) and protein efficiency ratio (PER) did not show significant differences between the fish in the control group and those on diet G20, although poorer FCR and PER outcomes were achieved in the case of fish on diet G60. The content of moisture, protein and ash in muscle and carcass increased as the proportion of Gracilaria meal in the diets increased, but the reverse was true for lipid level. These results indicate that incorporation of less than 20% red algae, Gracilaria arcuata, could be feasible in the diet of Nile tilapia and further studies are recommended to optimize the level of algae to improve growth performance.     

Phytase can reduce theneedfor monocalcium phosphate supplementation in soybean and rapeseed meal‐based diets of black sea bream,Acanthopagrus schlegelii (Bleeker, 1854)

A feeding trial was conducted to study the effect of partial replacement of dietary monocalcium phosphate (MCP) with phytase on growth performance, feed utilization and phosphorus discharge in black sea bream, Acanthopagrus schlegelii. In the feeding trial, the control diet (designated as P1.5) was prepared with 1.5% MCP but without phytase, and the three other diets (designated as PP1.0, PP0.5 and PP0, respectively) were supplemented with 1.0%, 0.5% and 0% MCP, respectively, along with 200 mg (400 U) phytase/kg diet in each. Each diet was tested in triplicate tanks and fish were fed twice daily to satiation. After an 8‐week feeding trial in indoor flow‐through cylindrical fibreglass tanks (25 fish per tank, initial body weight: 11.5 ± 0.12 g), fish fed with PP1.0 and PP0.5 had no significant change in weight gain (WG), specific growth rate (SGR), protein efficiency rate (PER) or feed conversion ratio (FCR) compared to the control (p > .05), whereas fish fed with PP0 showed a significantly lower growth performance in the above parameters (p < .05). The addition of phytase did not affect the body composition or muscle composition. The apparent digestibility coefficients (ADCs) of crude protein and phosphorus increased when fish were fed diets in which MCP was replaced by phytase. Phosphorus discharge was also significantly reduced in fish fed diets in which MCP was replaced by phytase (10.2 ± 0.50 to 8.01 ± 0.47 g/kg weight gain). The present study suggests that dietary MCP can be reduced when phytase is added to the black sea bream diet, with a maximum MCP reduction level of up to 1% when phytase is supplemented at 200 mg (400 U)/kg diet. Thus, phytase in the diet of black sea bream is economically and ecologically beneficial.     

Toxicological impact of Zinc Nano Particles on tilapia fish (Oreochromis mossambicus)

In this study we investigated the acute toxicity of Zinc Nano Particles (ZnO NPs) and bulk ZnO on tilapia fish (Oreochromis mossambicus). Oreochromis mossambicus was exposed to the different concentration of ZnO NPs, ZnO and mixed solution of both ZnO NPs and ZnO (20 ppb, 20 ppb, 20 ppb) respectively for 96 h. A very high impact was recorded in hematological parameters which shows significant increased (p < 0.05) in count of white WBCs and platelets in all the experimental groups compared tocontrol group. The count of RBCs, Hb, hematocrit and MCHC were significantly decreased. The remarkable changes which were recorded during this study were histopathological lesions in the gills of exposed fish including, disorganization of gill lamella, cartilaginous core disruption, lifting of epithelium, loss of secondary gill lamellae, blood congestion, fusion of secondary gills lamellae, shortening of secondary gills lamellae, atrophy and curling. Disassembly were seen in plasma membrane of liver along with blood congestion, pyknosis, necrosis, hyperplasia and formation of vacuoles. Intestinal alterations which were observed include shortening of villi, necrosis, detachment and fusion of villi and extreme goblet cells formation. It is concluded from the present study that high level of ZnO NPs, ZnO and mixed solution has a strong tendency to alter hematological parameters, histological architecture, therefore, the indiscriminate use of ZnO NPs and ZnO can subsidize in reducing the population of Oreochromis mossambicus in natural water bodies.     

Determination of synergistic effects of antibiotics and Zno NPs against isolated E. Coli and A. Baumannii bacterial strains from clinical samples

The mortality rates has been increased globally due to multidrug resistant (MDR) E.coli and A.baumanii bacterial strains and also there is an emerging resistance of the Enterobacteriaceae family of bacteria to Carbapenem antibiotics (CRE) in Saudi Arabia. The main aim of our research study is to isolate E.coli and A. baumannii bacterial species from various collected clinical samples and to evaluate the MIC and FICI of Colistin, Ciprofloxacin, Meropenem and ZnO NPs and in combination of Colistin, Ciprofloxacin, Meropenem with ZnO NPs.The clinical isolated strains of A. baumannii (MRO-17-13) and A. baumannii (MRO-17–25) was found to be sensitive towards colistin with 0.5 μg/mL concentration, whereas, all the isolated A. baumannii strains showed similar MIC value 2 mg/mL when tested with ZnO NPs, the MIC value for the ZnO NPs was found to be similar for all the E.coli strains 0.25 mg/mL. The effects of all Ciprofloxacin concentrations used in the study were bacteriostatic against E. coli (01UR19006568-01) strain but 1 mg/mL concentration of ZnO NPs alone is showed bactericidal activity, ZnO NPs effect was found to be concentration dependent, as highest concentration of ZnO NPs showed strongest antibacterial effect. In conclusion, more investigation is required to evaluate the acceptable concentration of Zno NPs and antibiotics selected to avoid toxicity and must be tested against more clinically isolated gram-negative bacterial strains.     

Acaricidal and biological activities of Titanium dioxide and Zinc oxide nanoparticles on the two-spotted spider mite,Tetranychus urticae Koch (Acari: Tetranychidae) and their side effects on the predatory mite,Neoseiulus californicus (Acari: Phytoseiidae)

The excessive application of pesticides raises environmental pollution levels, necessitating the need to identify alternative substances that do not cause ecological damage. In this context, the toxicity and residual efficacy of titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles (NPs) compared to abamectin against adult females of T. urticae was evaluated under laboratory and greenhouse conditions. In addition, the effects of tested NPs on the biological parameters of T. urticae as well as their side effects on the predatory mite, Neoseiulus californicus were examined. In laboratory bioassays, LC₅₀ values of TiO₂ and ZnO NPs were 5.82 and 7.09 mg L^–1, respectively, compared to 4.90 mg L^–1 in abamectin 72 hr post-treatment. TiO₂ and ZnO NPs had a prolongation effect on both the developmental and reproductive durations with mean life spans of 33.18 ± 0.72 days and 30.53 ± 0.82 days in the case of TiO₂ and ZnO NPs, respectively, compared to 24.65 ± 0.53 days in the normal case. Treated T. urticae females produced lesser fecundities (10–22 eggs less than the normal mean) and decreased hatchability rates. The highest mortality percentages in T. urticae populations were 92.4 % and 90.0 % after 24 h of spraying with TiO₂ and ZnO NPs, respectively, compared to 98.4 % in abamectin. In contrast, tested NPs demonstrated less toxicity in N. californicus populations with no phytotoxicity on treated leaves. This study is the first in Egypt to investigate the NPs control of T. urticae mites infesting cucumber plants and the effects on their biology and natural enemies.     

Dietary supplementation of fructooligosaccharide (FOS) improves the innate immune response, stress resistance, digestive enzyme activities and growth performance of Caspian roach (Rutilus rutilus) fry

The present study investigated the effects of prebiotic fructooligosaccharide (FOS) on the innate immune response, stress resistance, digestive enzyme activities, growth factors and survival of Caspian Roach (Rutilus rutilus) fry. After acclimation, fish (0.67 ± 0.03 g) were allocated into 12 tanks (50 fish per tank) and triplicate groups were fed a control diet or diets containing 1%, 2% or 3% FOS. At the end of the trial (7 weeks), humoral innate immune parameters (serum Ig levels, lysozyme activity and alternative complement activity (ACH50)), resistance to salinity stress (150 g L⁻¹), digestive enzyme activities (amylase, lipase and protease) and growth factors (final weight, weight gain, specific growth rate (SGR), food conversion ratio (FCR), and condition factor) were assessed. At the end of the study the innate immune responses (Ig levels, lysozyme activity and ACH50) were significantly higher in 2% and 3% FOS fed fish (P < 0.05), whereas, 1% dietary FOS only elevated serum lysozyme activity. All dietary FOS levels significantly increased resistance to a salinity stress challenge (P < 0.05) and highest survival was observed in the 3% FOS group. Similarly, digestive enzyme activities were significantly elevated with increasing levels of dietary FOS (P < 0.05). Subsequently, elevated growth performance (final weight, SGR and FCR) was observed in roach fed 2% and 3% FOS compared to the control group (P < 0.05). These results indicate that FOS can be considered as a beneficial dietary supplement for improving the immune response, stress resistance, digestive enzyme activities and growth performance of Caspian roach fry.     

Dietary supplementation of green synthesized manganese-oxide nanoparticles and its effect on growth performance,muscle composition and digestive enzyme activities of the giant freshwater prawn Macrobrachium rosenbergii

The green synthesized Mn₃O₄ nanoparticles (manganese-oxide nanoparticles) using Ananas comosus (L.) peel extract was characterized by various techniques. HR-SEM photograph showed that manganese-oxide nanoparticles (Mn-oxide NPs) were spherical in shape, with an average size of 40–50 nm. The Zeta potential revealed the surface charge of Mn-oxide NPs to be negative. Further, the Mn-oxide NPs were dietary supplemented for freshwater prawn Macrobrachium rosenbergii. The experimental basal diets were supplemented with Mn-oxide NPs at the rates of 0 (control), 3.0, 6.0, 9.0, 12, 15 and 18 mg/kg dry feed weight. The as-supplemented Mn-oxide NPs were fed in M. rosenbergii for a period of 90 days. The experimental study demonstrated that prawns fed with diet supplemented with 3–18 mg Mn-oxide NPs/kg shows enhanced (P < 0.05) growth performance, including final weight and weight gain (WG). Significant differences (P < 0.05) in feed conversion ratio (FCR) were observed in prawn fed with different diets. Additionally, prawns fed with 3.0–18 mg/kg Mn-oxide NPs supplemented diets achieved significant (P < 0.05) improvement in growth performance, digestive enzyme activities and muscle biochemical compositions, while, the prawns fed with 16 mg/kg of Mn-oxide NPs showed enhanced performance. Prawns fed on diet supplemented with 16 mg/kg Mn-oxide NPs showed significantly (P < 0.05) higher total protein level. The antioxidants enzymatic activity (SOD and CAT) metabolic enzymes status in muscle and hepatopancreas showed no significant (P > 0.05) alterations in prawns fed with 3.0–18 mg/kg of Mn-oxide NPs supplemented diets. Consequently, the present work proposed that 16 mg/kg of Mn-oxide NPs could be supplemented for flexible enhanced survival, growth and production of M. rosenbergii. Therefore, the data of the present study recommend the addition of 16 mg/kg of Mn-oxide NPs diet to developed prawn growth and antioxidant defense system.     

In vitro antimicrobial effect of metallic nanoparticles on phytopathogenic strains of crop plants

In this research, the in vitro antimicrobial effect of zinc oxide (ZnO), copper oxide (CuO) and iron oxide (Fe₂O₃) nanoparticles (NPs)—with average sizes of 20, 46 and 30 nm, respectively—on the root rot disease caused by the fungus Fusarium oxysporum and on blight disease caused by the fungus Alternaria solani were studied. Also, bacterial diseases caused by Clavibacter michiganensis and Pseudomonas syringae that infects a wide range of plant species were assessed. Different concentrations of NPs (0, 100, 250, 500, 700 and 1,000 mg/L) were prepared on PDA agar or King's B medium in a complete randomized design with four replicates. According to the results, ZnO NPs exhibited an outstanding inhibitory effect against fungi and bacteria strains. The above results were associated with the smaller particle size. Fungi strains showed a differential sensitivity depending on the kind of NPs used. A. solani showed the highest sensitivity to ZnO NPs at 1,000 mg/L (99%), followed by CuO NPs at the same dose (95%). Fe₂O₃ NPs at all evaluated doses had no inhibitory effects on the mycelia growth of this strain, although F. oxysporum revealed greater effectiveness of the CuO NPs (96%) compared with ZnO NPs since it only inhibited 91% of the mycelial growth. The antibacterial activity was studied through optical density. C. michiganensis was found to be more sensitive to ZnO NPs because a lesser dose (700 mg/L) was required to reduce the bacterial growth (90%); in comparison, P. syringae required a dose of 1,000 mg/L to inhibit its growth (67%). CuO NPs displayed the smallest growth inhibition against the bacteria strains analysed. The antimicrobial effect of the metallic NPs that were assayed increased with higher doses.     

Dietary lipid requirement on non-specific immune responses in juvenile grass carp (Ctenopharyngodon idella)

This study aimed to evaluate the dietary lipid requirement and its effects on liver oxidative status and non-specific immune responses of juvenile grass carp (Ctenopharyngodon idella). Purified diets with five dietary lipid levels (0%, 2.5%, 5%, 7.5% and 10%, fish oil/corn oil = 1:1) were each fed to triplicate groups of grass carp (mean initial weight: 6.57 ± 0.01 g) in a recirculating rearing system maintained at 27.5 ± 0.5 °C for 10 weeks. Percent weight gain was highest (P < 0.05) with 5% lipid and lowest in fish fed the lipid free control diet. Feed efficiency (FE) and protein efficiency ratio (PER) in fish followed the same pattern of percent weight gain. Fish fed with lipid containing diets had better non-specific immune response indexes (e.g. phagocytic activity, plasma peroxidase and lysozyme activity) and low-level of liver oxidation status than fish fed with the control diet. But excess dietary lipid supplement would bring over metabolic burden to liver. After the feeding trial, fish were challenged by Aeromonas hydrophila. Fish fed control diet obtained significantly (P < 0.05) lower survival rate. The survival rate was highest with 7.5% lipid. The results of this study indicated that proper dietary lipid supplementation enhanced the immune response of grass carp and improved the survival rate in the bacterial challenge, but excess dietary lipid may elevate liver oxidation rates of grass carp. Analysis by second-order regression of percent weight gain indicated that the optimal dietary lipid level in juvenile grass carp (6.6–35.5 g) is about 6.5%.     

Antifungal activity of zinc oxide nanoparticles against Botrytis cinerea and Penicillium expansum

Antifungal activities of zinc oxide nanoparticles (ZnO NPs) and their mode of action against two postharvest pathogenic fungi (Botrytis cinerea and Penicillium expansum) were investigated in this study. ZnO NPs with sizes of 70 ± 15 nm and concentrations of 0, 3, 6 and 12 mmol l⁻¹ were used. Traditional microbiological plating, scanning electron microscopy (SEM), and Raman spectroscopy were used to study antifungal activities of ZnO NPs and to characterize the changes in morphology and cellular compositions of fungal hyphae treated with ZnO NPs. Results show that ZnO NPs at concentrations greater than 3 mmol l⁻¹ can significantly inhibit the growth of B. cinerea and P. expansum. P. expansum was more sensitive to the treatment with ZnO NPs than B. cinerea. SEM images and Raman spectra indicate two different antifungal activities of ZnO NPs against B. cinerea and P. expansum. ZnO NPs inhibited the growth of B. cinerea by affecting cellular functions, which caused deformation in fungal hyphae. In comparison, ZnO NPs prevented the development of conidiophores and conidia of P. expansum, which eventually led to the death of fungal hyphae. These results suggest that ZnO NPs could be used as an effective fungicide in agricultural and food safety applications.     

The influence of various feeding patterns of emodin on growth,non-specific immune responses,and disease resistance to Aeromonas hydrophila in juvenile Wuchang bream (Megalobrama amblycephala)

The present study was conducted to evaluate the effect of various feeding patterns of emodin on growth, non-specific immune response, and disease resistance to Aeromonas hydrophila in juvenile Wuchang bream. Healthy Megalobrama amblycephala (initial weight: 3.47 ± 0.032) were grown in a circulating water system for 8 weeks. Five groups were studied: one control group was fed with a basal diet for eight weeks (Pattern 1, P1), and three treatment groups were fed with a trial diet of 30 mg emodin kg⁻¹ at one-week (Pattern 2, P2), two-week (Pattern 3, P3), four-week (Pattern 4, P4) intervals. The final treatment group maintained the trial diet for the entire eight-week study duration (Pattern 5, P5). Results indicated that different feeding patterns of emodin significantly influenced the weight gain rate of Wuchang bream (P < 0.05). Fish in the P4 treatment group had significantly higher rates of weight gain (WG) than those in other treatment groups. There were no significant differences in survival rates or feed conversion ratios (FCR) between treatment groups and the control group. White blood cell count (WBC), respiratory burst activity, superoxide dismutase (SOD) activity, myeloperoxidase (MPO) activity and tumor necrosis factor-α (TNF-α) activity were shown to increase at first and then decrease from P3 condition to P5 condition. Fish under P4 treatment showed the most significant improvement of all tested parameters compared to control. Significantly higher levels (P < 0.05) of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity were observed in P2 and P4 treatment groups when compared with the control group, while no significant differences were observed in the AST and ALT activity of fish in P2, P3, P4 and P5 treatment groups. In a bacterial challenge experiment with A. hydrophila, fish under P4 and P5 treatment showed lower cumulative mortality than the control group. The results of this study suggest that an initial 4-week feeding interval is recommended for the economic and practical culture of M. amblycephala.     

Dietary sodium butyrate ameliorated the blood stress biomarkers,heat shock proteins,and immune response of Nile tilapia (Oreochromis niloticus) exposed to heat stress

The present study investigated the effects of sodium butyrate (SB) on the growth performance, histomorphology, immune response, and stress related markers of Nile tilapia subjected to heat stress. SB was incorporated at 0, 0.5, 1, 1.5, and 2 g per kg diet and fed to fish for 8 weeks. The obtained results revealed significantly improved growth performance with a decreased feed conversion ratio in the fish fed SB (P < 0.05). In the anterior, middle, and distal parts of the intestine, villus length and width and internal villi distance as well as the number of goblet cells were increased in the fish fed SB (P < 0.05). The blood total protein, hemoglobin, and white and red blood cell counts showed a significant quadratic influence (P < 0.05). The survival rate for Nile tilapia exposed to heat stress for 48 h revealed that the SB fed groups had noticeably higher survival rates. Dietary SB significantly increased the phagocytic index and lysozyme and phagocytic activities both before and after heat stress (P < 0.05). After heat stress, blood glucose decreased significantly with SB feeding at 0.5, 1, or 1.5 g per kg diet, while cortisol was reduced in fish fed 1.5 or 2 g per kg diet (P < 0.05). Additionally, in fish fed SB, superoxide dismutase (SOD), catalase, and glutathione peroxidase activities were significantly increased both before and after heat stress, while malondialdehyde was decreased by SB feeding (P < 0.05). Liver heat shock protein 70 and SOD gene expression were significantly upregulated in fish fed on SB at 1 g per kg diet (P < 0.05). Thus, supplementation with SB at 1–2 g per kg diet can be used effectively in tilapia diets for improving growth, feed efficiency, and immune response as well as for tolerance to heat stress.     

R-Spondin1 enhances wnt signaling and decreases weight loss in short bowel syndrome zebrafish

BackgroundR-spondins, including R-spondin 1 (RSPO1), are a family of Wnt ligands that help to activate the canonical Wnt/β-catenin pathway, which is critical for intestinal epithelial cell proliferation and maintenance of intestinal stem cells. This proliferation underpins the epithelial expansion, or intestinal adaptation (IA), that occurs following massive bowel resection and short bowel syndrome (SBS). The purpose of this study was to identify if recombinant human RSPO1 (rhRSPO1) could be serially administered to SBS zebrafish to enhance cellular proliferation and IA.MethodsAdult male zebrafish were assigned to four groups: sham + PBS, SBS + PBS, sham + rhRSPO1, and SBS + rhRSPO1. Sham fish had a laparotomy alone. SBS fish had a laparotomy with distal intestinal ligation and creation of a proximal stoma. Fish were weighed at initial surgery and then weekly. rhRSPO1 was administered post-operatively following either a one- or two-week dosing schedule with either 3 or 5 intraperitoneal injections, respectively. Fish were harvested at 7 or 14 days with intestinal segments collected for analysis.ResultsRepeated intraperitoneal injection of rhRSPO1 was feasible and well tolerated. At 7 days, intestinal epithelial proliferation was increased by rhRSPO1. At 14 days, SBS + rhRSPO1 fish lost significantly less weight than SBS + PBS fish. Measurements of intestinal surface area were not increased by rhRSPO1 administration but immunofluorescent staining for β-catenin and gene expression for cyclin D1 was increased.ConclusionsIntraperitoneal injection of rhRSPO1 decreased weight loss in SBS zebrafish with increased β-catenin + cells and cyclin D1 expression at 14 days, indicating improved weight maintenance might result from increased activation of the canonical Wnt pathway.     

Effect of dietary chitosan on challenged <Emphasis Type="Italic">Dicentrarchus labrax</Emphasis> post larvae with <Emphasis Type="Italic">Aeromonas hydrophila</Emphasis>

Effect of different dietary squilla chitosan (Csq) concentrations: 0 (control), 0.5, 1 and 2 g 100 g^–1 diets were studied for weaned sea bass (Dicentrarchus labrax) post larvae. Post larvae were challenged with Aeromonas hydrophila after 5 feeding days, in order to monitor the prophylactic effect on the Csq fed larvae. The experiment started with an average initial weight of 50 ± 2 mg and total length of 12 ± 2 mm for post larval stage (40 days post hatch; dph), then continued feeding diets for a period of 20 days. Larvae survival percentage (%), mean total length (TL), width (W), total weight (TW), total weight gain (TWG), average daily weight (ADW) and specific growth rate (SGR) were recorded as morphometric measurements representing growth compared to the control groups. The results revealed that 1g Csq 100 g^–1 diet at P < 0.05 was the most effective concentration that achieved higher survival percentages; 94.5 ± 0.5 and 74 ± 2.0%, increasing the specific growth rate by 7.22% and 5.77% for non challenged and challenged weaned larval groups, respectively. Otherwise, the control challenged group displayed the lowest performance in all assayed parameters with the coincidental decrease in the survival % and specific growth rates. Similarly, lower growth performance was also observed at 2 g 100 g^–1 diet. Thus, the incorporation of chitosan at a level of 1g in fish diet enhanced the performance and reduced the fish mortality under stress conditions.     

Effect of feeding pineapple waste on growth performance,texture quality and flesh colour of nile tilapia (Oreochromis niloticus) fingerlings

The study aims to evaluate the effects of pineapples waste on the growth, texture quality and flesh colour of Nile tilapia (Oreochromis niloticus) fingerlings. Fingerlings were fed with four different levels of pineapple waste diets throughout 56 days, which contain a control group (Diet 1) and experimental diets that formulated with 10% (Diet 2), 20% (Diet 3) and 30% (Diet 4) of pineapple waste. The experimental diet was formulated with rice bran, fish meal, soybean meal, vitamin and mineral premix, vegetable oil and binder to attain 32% dietary protein. The results revealed that the formulated fish diet with pineapple waste given the optimum weight gain, weight gain percentage, specific growth rate than the control group, where Diet 4 has shown the highest value (p < 0.05). There were no effects of the pineapple waste diet on the texture quality of the fillet, while only red chromaticity (a*) showed a significant difference (p < 0.05). In conclusion, the addition of pineapple waste can improve the growth rate of Nile tilapia, and the supplementation level of the pineapple waste in the diet was 30% of the total feed formulation.     

Evaluation of red seaweed Gracilaria arcuata as dietary ingredient in African catfish,Clarias gariepinus

The aim of this study was to evaluate the use of dried marine seaweed, Gracilaria arcuata for the first time as dietary ingredient in partial substitution of fishmeal on the growth performance, feed utilization and body composition of African catfish, Clarias gariepinus. Four experimental diets were formulated: D1 as a control group; D2; D3 and D4 which included 10%, 20% and 30% G. arcuata meal respectively. One hundred and eighty African catfish weighing 9.62 ± 0.42 g, (mean ± SE) was divided into four groups corresponding to the different feeding regimes. The final body weight of the fishes showed significant differences (P < 0.05) between the control (D1); D2 and other treated groups D3 and D4, with weights of 66.98, 59.60, 47.34 and 30.73 g recorded for D1, D2, D3 and D4, respectively. Significant differences (P < 0.05) were also evident in weight gain, specific growth rate, and feed utilization between treatment and control groups. However, no significant differences (P > 0.05) were observed between the control group and fishes fed D2 for all previous parameters. Protein productive value, protein efficiency ratio, daily dry feed intake and total feed intake were also significantly lower in fish fed with a diet containing G. arcuata than in the control group and D2 which contains 10% of G. arcuata. Overall, the results of the experiment revealed that African catfish fed a diet with G. arcuata included in 20% and 30% levels showed poorer growth and feed utilization than the control group and D2. However, the study recommended that C. gariepinus can accept this ingredient up to 10% in their diets. More defined experiments therefore seem to be necessary in order to determine the maximum level of this marine seaweed in diets with amino acid supplementation for African catfish.