Dietary thyme essential oil (Thymus vulgaris) changes serum stress markers, enzyme activity, and hematological parameters in gibel carp (Carassius auratus gibelio) exposed to silver nanoparticles

Gibel carp (Carassius auratus gibelio) juveniles with an average weight of 8.73± 2.1 g were fed a basal diet (control) and three experimental diets (T200, T400 and T800), containing 200, 400 and 800 mgkg^-1, respectively of thyme essential oil (Thymus vulgaris) for six weeks. After six weeks feeding trial, both control and thyme essential oil-added feed groups were exposed to sub-acute toxicity of silver nanoparticles (Ag-NPs) for a period of 96 h. At 96 h after exposure, the number of erythrocytes (RBC), leucocyte (WBC), hematocrit (Hct), hemoglobin (Hb), the differential leukocyte count in blood and alanine aminotransferase (ALT), aspartate aminotransferase (AST) activity, HDL-cholesterol, LDL-cholesterol, cortisol and lactate in serum were measured. The results revealed feeding a thyme essential oil diet significantly conferred resistance to oxidative stress with sub-acute toxicity of Ag-NPs. Thyme essential oil enhanced the RBC and WBC count, hematocrit and hemoglobin content, at both low (T400) and high doses (T800). Biochemical analysis showed that serum ALT and AST activities, and LDL-cholesterol in the thyme essential oil-added feed groups were significantly reduced with increasing dietary thyme essential oil. Plasma HDL-cholesterol was significantly elevated by a high-dose of dietary thyme essential oil (T800). Furthermore, cortisol and lactate levels in serum significantly decreased throughout the thyme essential oil-added feed groups compared to the control. In summary, the use of thyme essential oil at 400 and 800 mgkg^-1, as dietary supplements, has potential to decrease oxidative stress of gibel carp providing resistance to non-fatal effects of pollutant by Ag-NPs

Gender and age blood parameters references in African catfish (Clarias gariepinus) cultured in earthen ponds during dry season in Ibadan metropolis, Nigeria

Blood analysis is important in fish health investigation and may be influenced by intrinsic and extrinsic factors. However difficulties exist in the use of blood analysis in the investigation of fish health due to the paucity of species specific, gender and age based reliable references. The current study therefore aims to determine some blood parameters in order to provide reliable references for dry season of the normal condition values of C. gariepinus, a widely cultured fish in Nigeria. This study involved random sampling of 900 C. gariepinus aged 4, 5 and 6 months from earthen pond for three years. Data obtained for blood parameters using standard method were analyzed using descriptive statistic, students'-test, one-way ANOVA level of significant set at p ~,0.05. Results showed the female had significantly (p ~,0.001) higher values than the males for each age bracket and the values increased sig nificantly (p 0~,.05) with increased in PCV. hemoglobin, RBC, WBC, total protein, potassium, sodium, Creatinine, ALT, AST and glucose. The females and males values at 4, 5 and 6 months old were PCV (32.14 ~c 0.19% vs 26.72 ~c 1.l2; 36.45 ~c 1.39% vs 32.33 ~c 1.46%; 40.83 ~c 0. 73% vs 35.01 ~c 0.08%.), total protein (3.98 ~c 0.16g/l vs 3.49 ~c 0.18g/l; 4.45 ~c 0.10g/l vs 4.33 ~c 0.04g/l). Lymphocytes, neutrophils, mono cytes and ESR values showed no stable trend in gender differences with increased age. In both the females and the males, lymphocytes decreased significantly (p ~,0.05) while neutrophils and monocytes increased significantly (p~,0.05) with increased age. ESR decreased significantly (P~, 0.05) in the males and non-significantly in the females with increase in age. It is hoped that these values obtained would serve as a reliable reference to enhance an appropriate intervention in the culture of C. gariepinus aged 4. 5 and 6 months in earthen pond which may be extrapolated for use in other culture systems

Behavior Changes and LC50 of Dried Garlic (Allium sativum) Acute Toxicity in Nile Tilapia (Oreochromis niloticus) Juvenile [RESEARCH NOTE]

Plant-based compounds are emerging substitutes for chemical treatments in aquaculture since they are known to cause less harm to both the environment and its organisms. Garlic (Allium sativum) is a popular herb that has a broad range of uses, especially in the control and treatment of bacterial and parasitic diseases. However, its toxicity to tilapia is not well-studied. Hence, this study was conducted to test the toxicity levels of garlic powder in juvenile Nile tilapia (Oreochromis niloticus) by determining the cumulative mortality and median lethal concentration (LC50). Test fish were exposed through immersion in 6 concentrations (150, 200, 250, 300, 350, and 400 mg L-1) of garlic powder with 25% allicin and a control in 96 h static bioassay. Within 24 h, test fish exposed to 250 mg L-1 garlic and above, exhibited abnormal behaviors such as lethargy, gasping for air, and weak responses to environmental stimuli. Cumulative mortality was highest at 100% in 400 mg L-1 garlic at 48 h. Mortalities were dependent on the concentration and duration of exposure. The 96 h LC50 of garlic powder to O. niloticus was 225.86 mg L-1 with lower and upper confidence limits of 210.37 and 242.50 mg L-1, respectively at 27°C

GROWTH PERFORMANCE, HEMATOLOGICAL AND HISTOLOGICAL PARAMETERS OF NILE TILAPIA LARVAE FED DIETS SUPPLEMENTED WITH B-GLUCANES AND NUCLEOTIDES

Food additives are used to improve immunity and performance. This study aimed to evaluate the dietary addition of nucleotides and ?-glucans in the larval stage of Nile tilapia on growth, hematoimmunological performance, histological changes, survival, and stress challenges. The experiment was conducted for 30 days using a total of 800 larvae distributed in 20 aquariums in four treatments: Diet without supplementation; diet supplemented with 0.75g · kg-1 ?-glucan; diet supplemented with 2g · kg-1 nucleotide and diet supplemented with 0.75 + 2g · kg-1 ?-glucan and nucleotide. The diet without supplementation had lower survival during the experimental period and after challenges and greater villus heights. Larvae fed a diet supplemented showed greater final weight, daily weight gain, total length and specific growth rate, better responses in the hypoxia test. Hematological parameters did not differ between treatments. The thickness of the villi was smaller in the treatment with nucleotide supplementation. In conclusion, treatment with a diet supplemented with ?-glucan + Nucleotides positively influenced the productive performance and survival rate of Nile tilapia larvae.Food additives such as nucleotides and ?-glucans are used to enhance the performance and immunity of aquatic organisms. This study aimed to evaluate the addition of these substances in the diet of Nile tilapia larvae, assessing growth, survival, hematological parameters, histological changes, and stress resistance. The experiment lasted 30 days, with 800 larvae distributed across 16 aquariums and divided into four treatments: control (no supplementation), ?-glucan (0.75 g kg-1), nucleotide (2 g kg-1), and ?-glucan + nucleotide (0.75 + 2 g kg-1). The larvae fed diets supplemented with ?-glucan showed higher final weight, daily weight gain, total length, and specific growth rate, and better performance in the hypoxia test. Larvae fed the combination of ?-glucan + nucleotides also differed from the control for the same parameters, except for length. After stress challenges with salinity and hypoxia, larvae in the control group showed lower survival, demonstrating that the supplementation of ?-glucan and nucleotides improves stress resistance and animal well-being. Intestinal villus thickness was reduced in the nucleotide-supplemented diet. In conclusion, the supplementation of ?-glucan and nucleotides has positive effects on the survival and performance of Nile tilapia larvae, particularly under stress conditions