Aquaculture is a rapidly growing food production sector globally. Aquaculture production provides an essential source of protein and micronutrients for humans. However, the expansion of aquaculture production has been accompanied by the use of intensive farming systems, thereby increasing the risk of disease outbreaks and fish mortality. Antibiotics are commonly used but are not recommended due to the emergence of antibiotic-resistant bacteria, environmental side effects, and changes in microbial communities.
Supplementing nerolidol into the diet of farmed tilapia helps improve fish growth and performance, along with increasing meat quality.
The aim of the study was to evaluate whether dietary supplementation with free nerolidol or nanoencapsulated nerolidol improves growth performance, meat antioxidant status, and fillet fatty acids in Nile tilapia.
Why add nerolidol to fish feed
Pharmaceutical manufacturers are beginning to replace natural products and nutritional additives that enhance the antioxidant system. These include essential oils and their isolated compounds such as sesquiterpenes.
Sesquiterpenes are C-15 terpenoids that occur as hydrocarbons or in oxidized forms such as alcohols, ketones, aldehydes, acids, or natural lactones. They are important components of essential oils with many significant applications in fish production. Nerolidol is a fatty alcohol sesquiterpene with several pharmacological properties including neuroprotective, trypanocidal, antibacterial, and antioxidant activities.
Research shows that using nanotechnology or loading nerolidol into nanotubes can increase its antioxidant capacity.
Nanotechnology is an attractive alternative solution to avoid excessive antibiotic use, to identify new natural bioactive compounds that can be used as growth promoters. This technology can be used to improve the efficacy of bioactive compounds.
The antioxidant properties of nerolidol will improve fish health, increase tilapia growth performance, and enhance antioxidant status and fatty acids in fillets.
Feeding Trial
The trial lasted 60 days, with diets containing 38% protein.
Fed with 5 diets: Control diet without supplementation (A); Supplementation with 0.5ml/kg feed nerolidol (B); 1ml/kg feed nerolidol (C); 0.5ml/kg feed nanoencapsulated nerolidol (D); 1ml/kg feed nanoencapsulated nerolidol (E).
Fish were weighed and measured at the beginning and end of the feeding trial. Parameters such as weight, specific growth rate (SGR), fish survival rate, and feed intake were monitored.
Fish were collected at the end of the trial for muscle fillet sampling. Tissue was evaluated for meat reactive oxygen species (ROS), meat hydrogen peroxide concentration, meat lipid peroxidation (LPO) levels, meat carbonyl protein content, and meat antioxidant capacity against peroxyl radicals (ACAP).
Fish fillets were also examined for meat superoxide dismutase (SOD) activity, meat catalase (CAT) activity, muscle protein content, and fatty acids.
Results
Supplementation with 1ml nano nerolidol/kg feed increased the final body weight and growth rate of fish compared to other diets. Fish receiving the supplemented feed had lower lipid peroxidation levels and reduced reactive oxygen species in the meat.
There were no significant differences in survival rate and feed intake among the treatments.
Nanoencapsulation of nerolidol promotes fish health by enhancing growth and reducing the production of lipid-damaging free radicals. It strengthens muscle tissue and boosts the production of antioxidant enzyme systems. Hydrogen peroxide concentrations decreased in fish supplemented with nerolidol.
Fish on the nanoencapsulated nerolidol diet had higher meat ACAP levels and increased CAT activity compared to fish on the non-nanoencapsulated nerolidol diet. There were no significant differences in SOD activity across the diets.
All supplemented diets showed lower saturated fatty acid (SFA) levels compared to results for fish receiving the control diet. However, total monounsaturated fatty acid (MUFA) content increased for supplemented fish.
The nanoencapsulation of nerolidol provides strong benefits for fish health. Improvements in growth performance and reduced levels of meat ROS (reactive oxygen species) and LPO (peroxidation) were observed in fish fed with nerolidol nanospheres. Both forms improved meat quality based on reduced SFAs and increased MUFAs, indicating that dietary supplementation with nanoencapsulated nerolidol is an attractive method to improve fish health and meat quality.
Source: Feed navigator
