Assessment of antibacterial activity of two different sizes of colloidal silver nanoparticle (cAgNPs) against Vibrio harveyi isolated from shrimp Litopenaeus vannamei

Abstract

Silver nanoparticles are the most important nanomaterials for antibacterial uses and are famous for their strong inhibitory and antibacterial effects. In recent years, extensive studies have been undertaken on the use of antimicrobial properties of silver, incorporated within aquaculture industry. To evaluate the scientific basis for the use of the nano silver in shrimp aquaculture, in this study the antimicrobial activities of colloidal nano silver with two different sizes (16.62 and 22.22 nm) was evaluated against gram negative bacteria, V. harveyi. Before the experiments, cAgNPs were characterized using several analytical techniques. Well diffusion method, micro-dilution tests (MIC and MBC) and kinetic of death were used to evaluate the bactericidal activity of the nanoparticles. Results showed that MIC and MBC values of cAgNPs in both studied sizes are equal (MIC = MBC). Best bactericidal kinetics in the presence of 16.62 and 22.22 nm nanoparticles obtained at 4 and 6 h, respectively. The obtained results suggested that smaller silver nanoparticles had a faster antibacterial activity than the larger particles. According to the obtained results, the activity of cAgNPs against V. harveyi is fast and has potential for the treatment of bacterial infection in aquaculture.

Effects of Dietary Silica Nanoparticle on Growth Performance, Protein Digestibility, Hematology, Digestive Morphology, and Muscle Composition of Nile Tilapia, Oreochromis Niloticus

“…The improved growth performance as seen in this study occurred because silica in nanoform may function as the nutrient carrier (especially for amino acids). These hauled nutrients could have further contributed to increasing the digestion and absorption of nutrient molecules through the controlled encapsulation and release of nutrients from the gastrointestinal tract to the bloodstream (Bahabadi et al, 2017). This increase could also be correlated with the amelioration of DNA and RNA syntheses and an improvement in gut microorganisms, which are supported by NPs (Onuegbu et al, 2018); however, this warrants a further investigation with silica NPs.…”

“…Silica NP was incorporated into diets at levels of 0 mg/Kg (T0), 1 mg/Kg (T1), 2 mg/kg (T2), and 3 mg/Kg (T3). As an innate marker, 0.05% Cr 2 O 3 was incorporated into diets for the further determination of the digestibility of tilapia according to Austreng (1978). The proximate compositions of the ingredients and diets were analyzed before and after the formulation of diets (Table 1), respectively, according to AOAC (2005) (for details, as shown in section Proximate Composition of Fish Muscle).…”

“…For the estimation of %APD and %DMD, five fish from each replication tank were sacrificed after 28 days (first stage) and 56 days (second stage) of feeding. In both stages, to avoid nutrient and marker leaching into the water, the fecal content was collected from the marginal gut, close to the anal region, following the method of Austreng (1978). Feces were extracted from each of the five fish sacrificed, weighed, and dried individually (thereby 15 replications for each treatment) in a hot-air oven (106 • C).…”