Dietary algal-sourced zinc nanoparticles promote growth performance, intestinal integrity, and immune response of Nile tilapia (Oreochromis niloticus).

BACKGROUND: Trace elements play a crucial role in fish nutrition, with zinc (Zn) being one of the most important elements. BIO-sourced zinc nanoparticles were synthesized using the green microalga Pediastrum boryanum (BIO-ZnNPs, 29.35 nm). 30 or 60 mg/ kg dry feed of the BIO-ZnNPs (BIO-ZnNPs30 and BIO-ZnNPs60) were mixed with the Nile tilapia (Oreochromis niloticus) basal diet and fed to the fish for 8 weeks to evaluate their impact on fish growth, digestion, intestinal integrity, antioxidative status, and immunity. RESULTS: A significant enhancement was observed in all investigated parameters, except for the serum protein profile. BIO-ZnNPs at 60 mg/kg feed elevated the activities of reduced glutathione (GSH) and catalase (CAT), enzymatic antioxidants, but did not induce oxidative stress as reflected by no change in MDA level. Fish intestinal immunity was improved in a dose-dependent manner, in terms of improved morphometry and a higher count of acid mucin-producing goblet cells. Interleukin-8 (IL-8) was upregulated in BIO-ZnNPs30 compared to BIO-ZnNPs60 and control fish groups, while no significant expressions were noted in tumor necrosis factor-alpha (TNFα), nuclear factor kappa B (NFkB), and Caspase3 genes. CONCLUSION: Overall, BIO-ZnNPs inclusion at 60 mg/kg feed showed the most advantage in different scenarios, compared to BIO-ZnNPs at 30 mg/kg feed. The positive effects on growth and intestinal health suggest that BIO-ZnNPs supplementation of aquafeeds has many benefits for farmed fish.

Impact of dietary administration of Arthrospira platensis free-lipid biomass on growth performance, body composition, redox status, immune responses, and some related genes of pacific whiteleg shrimp, Litopenaeus vannamei.

The current study aimed to assess the influence of dietary inclusion of cyanobacterium Arthrospira platensis NIOF17/003 as a dry material and as a free-lipid biomass (FL) on the growth performance, body composition, redox status, immune responses, and gene expression of whiteleg shrimp, Litopenaeus vannamei postlarvae. L. vannamei were fed five different supplemented diets; the first group was fed on an un-supplemented diet as a negative control group (C-N), the second group was fed on a commercial diet supplemented with 2% of A. platensis complete biomass as a positive control group (C-P20), whereas, the three remaining groups were fed on a commercial diet supplemented with graded amounts of FL at 1%, 2%, and 3% (FL10, FL20, and FL30, respectively). The obtained results indicated that the diet containing 1% FL significantly increased the growth performance, efficiency of consumed feed, and survival percentage of L. vannamei compared to both C-N and C-P20 groups. As for the carcass analysis, diets containing A. platensis or its FL at higher levels significantly increased the protein, lipid, and ash content compared to the C-N group. Moreover, the shrimp group fed on C-P20 and FL10 gave significantly stimulated higher digestive enzyme activities compared with C-N. The shrimp fed C-P20 or FL exhibited higher innate immune responses and promoted their redox status profile. Also, the shrimp fed a low FL levels significantly upregulated the expression of both the peroxiredoxin (Prx) and prophenoloxidase (PPO1) genes than those receiving C-N. The current results recommended that dietary supplementation with 1% FL is the most effective treatment in promoting the performance and immunity of whiteleg shrimp.

Arthrospira platensis nanoparticles dietary supplementation improves growth performance, steroid hormone balance, and reproductive productivity of Nile tilapia (Oreochromis niloticus) broodstock.

This study evaluates the impact of dietary supplementation of the blue-green alga Arthrospira platensis NIOF17/003 nanoparticles (AN) on the growth performance, whole-body biochemical compositions, blood biochemistry, steroid hormonal, and fry production efficiency of Nile tilapia (Oreochromis niloticus) broodstock, during the spawning season. After a 21-day preparation period to equip the females and ensure that their ovaries were filled with eggs, mating between the mature females and males took place in a 3:1 ratio during a 14-day spawning cycle. A total of 384 tilapia broodstock 288 females and 96 males with an initial body weight of 450.53±0.75, were divided into four groups; AN0: a basal diet as a control group with no supplementation of Arthrospira platensis, and the other three groups (AN2, AN4, and AN6) were diets supplemented with nanoparticles of A. platensis at levels of 2, 4, and 6 g kg─1 diet, respectively. The results found that fish-fed group AN6 showed the highest significant differences in weight gain (WG), final weight (FW), feed conversion ratio (FCR), protein efficiency ratio (PER), and feed efficiency ratio (FER). Females fed the AN6 diet showed the highest significant fat content. Compared to the AN0 group, fish fed on the supplemented diets showed significant improvement (p < 0.05) in triglyceride, glucose, and aspartate aminotransferase (AST). A gradual increase in AN inclusion level resulted in a gradual increase in the concentrations of luteinizing hormone (LH), and follicle-stimulating hormone (FSH), testosterone, progesterone, and prolactin. The rates (%) of increase in fry production for females fed supplemented diets were 10.5, 18.6, and 32.2% for AN2, AN4, and AN6, respectively, compared to the control group. This work concluded that the inclusion levels of 6 g kg─1 of A. platensis nanoparticles in the diet of Nile tilapia broodstock significantly improved the growth performances, steroid hormone concentrations, and increased the fry production efficiency by 32.2%, respectively. These findings revealed that A. platensis nanoparticles resulted in a significantly enhanced female' reproductive productivity of Nile tilapia broodstock.