The effects of different levels of chitosan, ZnO and chitosan–ZnO NPs on growth performance, proximate composition and digestive enzyme activity in Pacific white shrimp (Penaeus vannamei)

Abstract

Introduction: In the present study, the effect of different levels of dietary supplement chitosan, zinc oxide and zinc oxide nanoparticles coated with chitosan on growth indices, survival, body chemical composition and digestive enzyme activity of Pacific white shrimp was investigated for 90 days.
Materials & Methods: For this purpose, shrimps with an average weight of 3.27 ± 0.11 g in 300-liter fiberglass tanks with a density of 40 shrimps per tank, in the form of eight different treatments with levels of 10, 20 and 40 mg/kg of dietary supplement containing zinc oxide and zinc oxide nanoparticles coated with chitosan and 36 (mg/kg) chitosan and control treatment (without additive) were fed with 3 replicates. At the end of the period, the growth indices including average body weight gain, body weight gain, specific growth ratio and food conversion ratio, survival rate, body chemical composition and digestive enzymes activity (amylase, lipase and protease) were compared with the control treatment.
Results: The results showed that the use of different levels of zinc oxide and zinc oxide nanoparticles coated with chitosan in the diet significantly improved the growth and survival indices, so that the most appropriate increase in body weight, specific growth rate and the food conversion ratio was observed in the treatments of zinc oxide 20 and zinc oxide nanoparticles coated with chitosan 10 mg/kg (p<0.05). Regarding the biochemical analysis of the carcass and the activity of digestive enzymes, the results indicated a significant increase in the amount of protein and fat and the activity of amylase, lipase and protease enzymes in the experimental treatments compared with the control treatment (p<0.05).
Conclusion: The results of this study showed that the level of 10 mg/kg zinc oxide coated with chitosan in the diet could be used to improve growth performance, survival, digestive enzymes activity and carcass quality of Pacific white shrimp.