WWW.WAS.ORG • WORLD AQUACULTURE • JUNE 2013 65 The goal of the investigation described here was to assess the effects of a common probiotic bacterium, Bacillus subtilis, and herbal additives Indian almond Terminalia catappa and aloe Aloe vera on growth performance, survival and disease resistance of striped murrel fingerlings challenged by A. hydrophila. Effects on Growth Rate Four experimental diets were prepared (Table 1). Each of three diets contained one of the following feed additives (Fig. 2): Bacillus subtilis, Indian almond Terminalia catappa and aloe Aloe vera. A fourth (control) diet was prepared without feed additives. Ingredients were mixed with feed additives and autoclaved, semi-moist feeds were prepared and stored at -20 C. Striped murrel fingerlings (1.0±0.2 g/fish) were obtained from the Centre for Aquaculture Research and Extension (CARE) Aquafarm, St. Xavier’s College, Palayamkottai, Tamil Nadu, India and stocked into cement tanks (300 L) filled with groundwater at 10 fingerlings per tank in triplicate for each treatment. Fingerlings were fed 5 percent of body weight daily, divided into three feedings, for 50 days and the feeding rate was adjusted every 10 days. Growth parameters were calculated using standard methods (Adewolu 2008). Growth of striped murrel fed diets with a probiotic bacterium and aloe were not different from striped murrel fed the control diet. However, growth of striped murrel fed the diet with Indian almond was substantially greater than that of fish fed the control diet (Table 2). Some herbs promote cellular lipid and fatty acid utilization and protein accumulation resulting in good growth performance (Ji et al. 2007). The growth increase in rohu Labeo rohita fed with herbal supplemented diet was a result of improved food utilization and high protein synthesis (Johnson and Banerji 2007). Effects of Disease Challenge A. hydrophila was isolated from diseased striped murrel (CONTINUED ON PAGE 66) TABLE 1. Semi-moist feed for Channa striata. Ingredient % Fishmeal, anchovy 26.9 Soybean flour 25 Jawala, Acetes sp. 20 Tapioca meal 10.9 Wheat flour 10 Sunflower oil 5.8 Monosodium phosphate 0.3 Mineral premix 0.5 Aqua Saver 0.3 Vitamin and Mineral premix 0.1 Feed additive 0.2 a Vitamin mixture providing the following concentration per kilogram diet; vitamin A 5000 IU; vit D 400 IU; vit E 20 mg; thiamin mononitrate (B1) 4 mg; riboflavin (B2) 6 mg; nicotinamide 50 mg; pyridoxine hydrochloride 3 mg; calcium pentohenate 10 mg; cyanocobalamine (B12) 2mg; ascorbic acid (vit C) 100 mg; biotin 0.1 mg. b Trace mineral mix use providing the following concentration (ppm) copper 10; iron 100; manganese 50; zinc 50; cobalt 0.05; and iodine 0.1 (Dhanaraj and Haniffa 2011). Feed additives- B. subtilis, T. catappa, A. vera. TOP LEFT, FIGURE 3. Injection of A. hydrophila to C. striatus fingerlings. TOP RIGHT, FIGURE 4. Effect of feed additives on weight gain in C. striatus fingerlines fedd different feeds. LEFT, FIGURE 5. Fingerlings of C. striatus showing skin lesions challenged by A. hydrophila.
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