Effects of dietary supplementation of chamomile oil on Indian shrimp (Penaeus indicus) performance, antioxidant, innate immunity, and resistance to Vibrio parahaemolyticus infection

Abstract

The stimulatory effects of dietary chamomile (Matricaria chamomilla) oil (ChO) on Indian shrimp (Penaeus indicus)’s growth performance, biochemical parameters, antioxidants, innate immunity, and resistance to Vibrio parahaemolyticus infection were investigated. Shrimp (4.0–4.5 g) were fed with diets enriched with 0.0 (control), 1.0, 3.0, and 5.0 g ChO/kg feed three times a day to apparent satiety for 56 days. Intramuscularly, V. parahaemolyticus were injected after the feeding trial, and clinical symptoms and mortalities were observed for 96 h. In ChO-fed animals, growth-stimulating effects were found on final weight, weight gain, specific growth rate, and feed intake with an optimum level of 3 g/kg diet. Dietary ChO did not significantly affect feed conversion ratio, protein efficienct ratio, protein productive value, and energy utlilization. Serum protein (total protein, albumin, and globulin) profile, as well as antioxidant and immunity variables, significantly higher in ChO-fed animals particularly at the 3.0 and 5.0 g/kg feed treatments. Conversily, significant reductions in levels of aspartate and alanine aminotransferase, creatinine, urea, malondialdehyde, and nitric oxide were detected in animals fed 3.0 or 5.0 g ChO/kg feed. Vibrio spp. showed low abundance in the gills and intestine of ChO-fed Indian shrimp compared to the control one; particularly in the treatments of 3.0 and 5.0 g/kg feed. The control group died completely after the bacterial challenge; however, ChO-fed animals were more resistant, with relative survival rates of 80.0% and 86.7% in the 3.0 and 5.0 g ChO/kg feed treatments, respectively, with no significant difference between them. Therefore, diets containing 3.0 g ChO/kg feed were found to be optimum for Indian shrimp, boosting its growth, antioxidant capacity, and innate immunity. Furthermore, ChO-enriched diets effectively increased its resistance to infection by V. parahaemolyticus.