Innate Immune Response and Growth Performance of Heterobranchus longifilis Catfish Juveniles Following Dietary Aflatoxin B1 Exposure

We evaluated the effects of dietary aflatoxin B1 (AFB ) exposure on the immune response and the 1 growth performance of Heterobranchus longifilis catfish; and determined the maximum tolerable limits for AFB in H. longifilis. Five experimental isocaloric and isonitrogenous diets amended 1 with varied concentrations of AFB [Diet A (2.0 μg AFB .kg-1); Diet B (7.3 μg AFB .kg-1); Diet C 1 1 1 (17.6 μg AFB .kg-1); Diet D (48.0 μg AFB .kg-1) and Diet E (93.0 μg AFB .kg-1)] were fed to 450 1 1 1 juvenile H. longifilis in five groups of 15 separate plastic tanks for a period or 56 days. At time points day 7, 14, 28 and day 56, five fish were randomly sampled per tank and assessed for innate immunity and growth response. Fish fed diets amended with AFB exhibited significant reduction 1 (P < 0.05) in the serum lysozyme and epidermal mucus lysozyme activity, epidermal mucus alkaline phosphatase activity and in the phagocyte respiratory burst activity. These parameters decreased with increasing concentrations and duration of dietary AFB (P< 0.05). Dietary AFB 1 1 caused significant reductions in the growth performance of juvenile H. longifilis marked by reductions in the percentage gain in length, reduction in percentage gain in weight and a reduction in the specific growth rate. Based on these results, juvenile H. longifilis catfish appears to tolerate diets containing up to 17.6 μg. Kg-1 AFB in diets.

Assessment of immunohematological, hematological and biochemical responses in cultivable fish Cyprinus carpio exposed to an antibiotic sulfamethoxazole (SMX)

Sulfamethoxazole (SMX) is a member of the sulfonamides group of antibiotics which is used extensively in aquaculture throughout the world. In this study, common carp (Cyprinus carpio) was used as the bioindicator to assess the toxicity potential of SMX. Effects were based on chronic toxicity of environmentally relevant dosages of 25, 50, 100, and 200 μg/L of SMX for 28 days. Cytotoxicity through hematology and biochemistry showed a dose–response relationship. Numerous variations were recorded in blood profile and biochemical parameters in SMX-exposed groups when compared to control. Hemoglobin, platelet, and erythrocyte levels were significantly decreased. Leukocyte level was significantly increased with values ranging from 131 to 303 (×103/μL). Changes in biochemical indices: glucose, total protein, and triglycerides showed biphasic trend, but alanine transaminase secretion was significantly increased from 25.13 to 204 U/L at higher concentration compared to control, suggesting liver damage. Spectrophotometric nitroblue tetrazolium reduction assay showed that respiratory burst activity increased as a function of SMX dose and exposure time (0.48–1.33 absorbance) ultimately leading to reduction in immunity. The present study highlights that prolonged exposure of SMX affects biochemistry, hematology, and immunohematology of fish and these biomarkers act as an effective tool for environmental risk assessment of drugs in the aquatic environment.

Effect of dietary inclusion of a commercial polyherbal formulation on some physiological and immune parameters in healthy and stressed hens

The effects of the dietary inclusion of a polyherbal formulation based on three powdered herbs (W. somnifera, T. cordifolia, O. sanctum) on some physiological and immune parameters were studied in healthy and stressed laying hens. The effects of the dietary polyherbal formulation were also compared with those of dietary ascorbic acid (AA) supplement, nowadays considered one of the most potent immunostimulant substances widely used as a food supplement.Experimental data did not show any positive effects, or very low ones, on the assessed parameters in healthy hens as a consequence of the two dietary supplementations. On the contrary, the dietary inclusion of the polyherbal mixture or AA partially counteracted the adverse effects in hens subjected to a moderate and transient dexamethasone-induced stress, when ameliorating effects on natural IgM antibody level, specific antibody response, total immunoglobulin content, respiratory burst activity and total antioxidant capacity were shown. The obtained results justify the ethnomedical use of this polyherbal mixture in stressed laying hens in which faster recovery has been demonstrated, whereas healthy specimens did not seem to substantially benefit from the dietary integration, neither with the polyherbal product nor with AA. Thus, the presence of nutraceutical compounds in several herbal plants exerting no side-effects might be useful for exploring them as an alternative to allopathic substances for preventive or therapeutic purposes in poultry.

Biochemical and haematological responses to thermal stress in Labeo rohita (Hamilton, 1822) fingerlings

An experiment was conducted to understand the effect of thermal shock on stress and recovery in Labeo rohita (Hamilton, 1822) fingerlings. L. rohita fingerlings were exposed to a temperature of 380C for 2 h and permitted to recuperate afterwards for 48 h. Primary and secondary stress parameters were analysed after 2, 4, 8, 12, 24 and 48 h of recovery. The activity of glucose-6-phosphate dehydrogenase and acetylcholine esterase reduced significantly (p<0.05). Erythrocytes, haemoglobin, respiratory burst activity and lysozyme levels increased significantly (p<0.05) by 7.31, 23.91, 109.09 and 70.13% after thermal shock, whereas leucocytes, serum protein, albumin and globulin showed a reverse trend. During recovery, biochemical parameters normalised in 48 h. However, immunological variables such as serum total protein, albumin and globulin, and histopathological changes in gill and kidney tissues did not return to normal condition.

Innate immune responses of whiteleg shrimp (Penaeus vannamei) experimentally infected with acute hepatopancreas necrosis disease-causing Vibbrio parahaemolyticus

The innate immune responses of the whiteleg shrimps (Penaeus vannamei) experimentally challenged with V. parahaemolyticus by immersion were investigated for a period of 120 h. The results showed that the lethal dose 50% (LD50) of shrimps (2 - 3 g) challenged with V. parahaemolyticus was 4.7 × 106 CFU/mL. No significant differences in immune parameters were observed between the control and challenged group right after challenge (0 hpi). However, the total haemocyte count, phenoloxidase activity and respiratory burst activity were decreased in the challenged shrimps after 24 and 48 hpi and significantly different from those in the control shrimps (P < 0,05). At 72, 96 and 120 hpi, there were no significant differences in the total haemocyte count, phenoloxidase activity and respiratory burst activity between two treatments. The observations of this study showed that the innate immune responses of the whiteleg shrimp were decreased due to the infection by V. parahaemolyticus.

Functional features of neutrophils in subclinical hypothyroidism compared to euthyroid status

Neutrophil or polymorphonuclear leukocytes are critical to host defense. They act by migrating (chemotaxis) to site of inflammation or infection, phagocytoze the microorganisms to form phagosome. Reactive Oxygen species and hydrolytic enzymes are released (respiratory burst activity) into this phagosome to kill ingested microorganisms (microbicidal activity). Thyroid hormones are essential for proper differentiation, growth and metabolism of an organism. Increasing evidence indicates that thyroid hormones also play an active role in immunity. Subclinical hypothyroidism is associated with normal thyroid hormone levels with increased thyroid stimulating hormone level. While studies indicate elevated TSH to have some effects on immune functions, there is very little evidence regarding its effect on functional features of neutrophils. In this cross-sectional comparative study, we evaluated the phagocytic, chemotactic, candidacidal, and respiratory burst activity of neutrophils in subclinical hypothyroid and euthyroid subjects. Phagocytosis and metabolic function of the neutrophils was assessed using Nitro-blue tetrazolium test. Chemotaxis, directional movement of the PMNs was measured using the N-Formyl methionyl-leucyl-phenylalanine as chemoattractant. Phagocytic activity was evaluated by exposing leukocytes to candida suspension and counting the number of candida ingested and killed. Microbicidal activity of neutrophils was assessed by the ability of leukocytes to kill Candida albicans in both subclinical hypothyroid and euthyroid subjects. Our study demonstrated that chemotactic and mean phagocytic activity was significantly less in those with subclinical hypothyroidism as compared to euthyroid control group (p value = 0.005 and 0.045 respectively). Respiratory burst activities of both unstimulated & stimulated neutrophils were relatively reduced in subclinical hypothyroidism (p value of 0.08 and 0.07). Candidicidal activity was similar in both groups. We conclude that subclinical hypothyroid individuals having excess of thyroid stimulating hormones are associated altered functional characteristics of neutrophils.