The effects of dietary Spirulina platensis or curcumin nanoparticles on performance, body chemical composition, blood biochemical, digestive enzyme, antioxidant and immune activities of Oreochromis niloticus fingerlings.

CONTEXT: Recently, prioritize has been given to using natural phytogenic or nano compounds as growth promoters and immunostimulants in fish diets as an alternative to antibiotics. AIMS: The main propose of this trial was to determine the impact of supplementing diets with spirulina or curcumin nanoparticles on the performance and health indicators of Nile tilapia fingerlings. METHODS: In a 56-day feeding trial, 180 tilapia fingerlings were assigned into three main groups, as follows: 1st, control group, 2nd, Spirulina platensis (SP; 5 g kg-1 diet) and 3rd, curcumin nanoparticles (CUR-NPs; 30 mg kg-1 diet). KEY RESULTS: Incorporating tilapia diets with SP or CUR-NPs significantly improved performance, body chemical analysis, blood biochemical and hematological indices, digestive enzyme activities, and antioxidant and immunostimulant features compared to the control. CONCLUSION: Fortified tilapia diets with CUR-NPs or SP efficiently boost the productivity and health of Nile tilapia fingerlings. IMPLICATIONS: The research introduces new practical solutions for applying safe feed additives as alternatives to antibiotics in tilapia farming.

Growth, sex reversal pattern, and reproductive characteristics of Barramundi (Lates calcarifer) broodstock candidates reared in floating cages.

Sex reversal of male to female is a characteristic of barramundi (Lates calcarifer), which is affected by several factors, thereby changing the broodstock population. A study was conducted in floating cages in Langkawi, Malaysia, to determine the weight point at the onset of the sex reversal phenomena. A total of 75 female and 55 male adult individuals (3-4 weeks of age) were sampled from the fish cultured in cages to ascertain their sex at different weights. The water temperature and salinity values were 29.82 °C and 33.12 ppt, respectively. The specimens were classified into twelve bodyweight classes (2.00-8.00 ± 0.5 kg intervals). Female specimen body weight distribution was highest in the 6.01-6.50 kg class (22.6%), followed by the 5.51-6.00 kg and 4.51-5.00 class (13.3%), while male specimen body weight distribution was highest in the 4.51-5.00 kg class (32.1%), followed by the 4.01-4.50 kg class (30.3%). Length-to-weight relationships for females and males of Asian Seabass indicated positive allometric growth. The correlation between body weight and GSI, using Pearson's correlation, for both sexes, for the male and female barramundi, there was a weak correlation between body weight and GSI, which was 37 and 30%, respectively. Based on the present study's findings, it can be concluded that sex reversal from male to female in Barramundi largely occurred at 4.57 kg body weight and 66.8 cm total length.

Dietary curcumin nanoparticles promoted the performance, antioxidant activity, and humoral immunity, and modulated the hepatic and intestinal histology of Nile tilapia fingerlings.

The current study investigated the effects of dietary curcumin nanoparticles (C-NPs) on the performance, hemato-biochemical profile, digestive enzymes activities, antioxidant status, humoral immunity, and liver and intestinal histology of Nile tilapia (Oreochromis niloticus). Fish (4.3 ± 0.5 g) were fed with diets enriched with 0.0 (control), 15, 30, 45, and 60 mg C-NPs/kg diet up to apparent satiety thrice a day for 60 days. The growth-stimulating effects of dietary C-NPs were significantly observed in terms of final weight, weight gain %, specific growth rate, and feed intake. Compared with the control group, serum amylase, lipase, and proteases activities of Nile tilapia significantly (P < 0.05) increased alongside the increase in dietary levels of C-NPs in a dose-dependent manner. The counts of red blood cells and white blood cells as well as hemoglobin and hematocrit levels of Nile tilapia fed with 30-60 mg C-NPs/kg diet were statistically (P < 0.05) higher than fish in the control group with no significant differences among them (P > 0.05). Moreover, lymphocytes and monocytes significantly (P > 0.05) increased; meanwhile neutrophils significantly (P > 0.05) decreased as C-NPs levels in diets increased. In a similar trend, antioxidant (malondialdehyde, superoxide dismutase, catalase, and glutathione peroxidase) and humoral immunity (lysozyme and total immunoglobulin) biomarkers were significantly higher in C-NPs-fed fish. Liver histology showed improvements in the cell architecture of fish fed with C-NPs containing diets up to 45 mg/kg diet. Compared with the control diet, feeding Nile tilapia with C-NPs diets resulted in a higher villi length/width and absorption area. According to the regression curves, the current study recommends using the dietary C-NP with optimum values of 45-55 mg/kg diet to improve the performance, digestive enzymes, antioxidant activities, and immunity response of Nile tilapia.