Stress is a common factor among all animals and aquatic species which were suffer from wide variety of stresses especially management stress, nutritional stress, environmental stress. The present study was aimed to evaluate the efficacy of phytocee in Vit-C phosphate(C-PP) reduction diets on the performance of white shrimp under density stress condition and disease challenge against Vibriosis AHPND. Phytocee is phytogenic feed additive as adaptogen to mitigate and reduce stress in animals. Both phytocee and Vit-C phosphate are considered to have function on health and growth of shrimp reared in high density including immune response after pathogen challenge test.
An experiment was conducted based on a CRD, with 5 treatments and 5 replicates each. All 5 diets were supplemented different level of C-PP in combination with 0.1% Phytocee applied to selected groups as Table 1.
Shrimp with initial mean weight of 1.4 g/shrimp were randomly distributed into 240L glass aquarium (Total 25 aquariums) that contained 120L of 15 ppt seawater. Stocked 30 shrimp per aquarium (250 pcs/m3). During 8 weeks of feeding trial, shrimp were fed experimental diets 3-5%BW 4 times a day and weighted on week 0, 4 and 8 for determined growth performance. Haemolymph samples were collected to study their immune response both under density stress condition and after challenge test by bath treatment against 6.2X105 CFU/ml of Vibrio parahaemolyticus AHPND for 12 days, mortality was recorded.
The results showed that the shrimp fed diets 0.1% phytocee in T4 and T5 had significantly higher (p<0.05) total production per aquarium. Moreover, shrimp fed diets 0.1% phytocee in T3, T4 and T5 had significantly higher (p<0.05) final weight, weight gain, average daily growth (ADG), specific growth rate (%) and better feed conversion ratio (FCR). The immune response of shrimp as total haemocyte count, hemolymph protein and phenoloxidase activity (PO) were not significantly differences (p>0.05). After AHPND challenging, the results found that, phenoloxidase activity of shrimp fed diets 0.1% phytocee in T3, T4 and T5 had significantly higher (p<0.05) than T1 and T2. The survival rate after AHPND challenging was not significantly differences (p>0.05). In conclusion, 0.1% phytocee showed the benefit on reducing C-PP in shrimp diets by 250-500 g/ton(25-50% reduction) without any adverse effects on growth and immune response under density stress condition and Vibriosis challenge test.