Bacillus is a species widely used as a probiotic in the aquaculture industry. The Bacillus spores have more advantages than their vegetative ones, and an addition of minerals such as calcium, magnesium, and manganese can improve the spore production. The purpose of this study was to determine the effect of different sources of manganese on the production and sporulation efficacy of B. subtilis SB3. The sources of manganese used in this study were manganese chloride (MnCl2) and manganese sulfate (MnSO4) at the concentration of 10 mM. Media without manganese supplementation was used as a control. The results showed that there was a significant effect of different manganese sources on the spore production of B. subtilis SB3. The highest spore production was found in media with MnCl2 supplementation with the total spore of 8.77 x 107 spores. mL-1. However, spore production with MnSO4 supplementation was still higher (22.7%) compared to that without manganese supplementation. The decrease in spore production with MnSO4 supplementation was possible due to the sulfate inhibition. The high spore production in media with MnCl2 supplementation was also preceded by the high production of vegetative cells from B. subtilis SB3 (2.54 x 108 cells. mL-1). The results indicated that manganese could stimulate both vegetative cell growth and its spores. The highest sporulation efficacy (35%) was also achieved in media with MnCl2 supplementation. On the other hand, the germination rate of B. subtilis SB3 spores was not influenced by manganese supplementation.Abstrak Bacillus adalah species yang banyak digunakan sebagai probiotik pada industri akuakultur. Dalam bentuk spora, species ini lebih banyak mempunyai kelebihan dibandingkan dalam bentuk vegetatifnya dan peningkatan produksi sporanya dapat dilakukan dengan penambahan mineral seperti kalsium, magnesium dan mangan. Tujuan penelitian ini adalah untuk mengetahui pengaruh sumber mangan yang berbeda terhadap produksi dan efisiensi sporulasi B. subtilis SB3 indigenous akuatik. Sumber mangan yang dipakai dalam penelitian ini adalah mangan klorida (MnCl2) dan mangan sulfat (MnSO4) sebanyak 10 mM dan sebagai kontrol digunakan media tanpa suplementasi mangan. Hasil penelitian menunjukkan bahwa terdapat pengaruh yang nyata penggunaan sumber mangan yang berbeda terhadap produksi spora. Produksi spora tertinggi didapatkan pada media dengan suplementasi MnCl2 sebanyak 8,77 x 107 spora. mL-1. Sedangkan produksi spora dengan suplementasi MnSO4 juga masih lebih tinggi (22,7%) dibandingkan tanpa suplementasi magan. Penurunan produksi spora pada media dengan penambahan mangan sulfat diduga karena adanya penghambatan oleh sulfat. Tingginya produksi spora pada media dengan suplementasi MnCl2 sebelumnya juga didahului dengan tingginya produksi sel vegetatif dari B. subtilis SB3 (2,54 x 108sel. mL-1). Hal ini menunjukkan bahwa mangan dapat menstimulasi baik pertumbuhan sel vegetatif dan sporanya. Efisiensi sporulasi tertinggi juga dicapai pada media dengan suplementasi MnCl2 sebesar 35%. Di sisi lain, kemampuan germinasi spora B. subtilis SB3 tercatat sama dan tidak dipengaruhi oleh suplementasi mangan.

Developing a sustainable feed with minimal or no fishmeal in tilapia production is a challenge to this industry. New Technology Promoter Binder (NTPB), a guanidinoacetic acid, is a nutritional supplement to enhance the energy metabolism of the muscle and brain tissue of vertebrates. This study aimed to evaluate several plant-based diet formulations with zero and minimal use of fishmeal enriched with NTPB on the growth, feed efficiency, and health status of Tilapia sp. The experimental diets in this study were conducted based on four formulations (minimum fishmeal/FM and zero fishmeal/NFM-based diets) with 0, 0.6, and 1.2 g·kg⁻¹ feed of NTPB supplementation. The research indicated that the various diets given to tilapia affected the growth performance of fish in terms of growth parameters and feed efficiency. Tilapias fed with NTPB grew better than those without NTPB in both FM- and NFM-based diets. The addition of NTPB was safe for tilapia as demonstrated in the blood glucose, urea, and creatinine levels, which were normal for healthy fish. The viscerosomatic and hepatosomatic indexes of tilapia fed with the experimental diets showed no distinct differences. Adding NTPB to tilapia diets increased the hardness and amino acid contents of the tilapia’s muscle, which would benefit consumers.

Probiotic is considered an effective means for disease prevention in the aquaculture system. The most of probiotic species used in aquaculture were Bacillus in the form of vegetative cells. Therefore, this study evaluates the immune responses of Oreochromis niloticus under the Bacillus supplementation in the form of vegetative cells and spore. The addition of vegetative cells and spore Bacillus was given in the fish diet for 49 days. Several non-specific immune responses were evaluated afterward. Treatment without Bacillus supplementation in the diet was used as a control. The results showed that Bacillus supplementation in the form of spore and vegetative increased the non-specific immune response compared to those of control. Some parameters of the immune response, such as total leukocytes, haematocrit value, and respiratory burst, were affected by the form of Bacillus supplementation. Total haematocrit (31.67%), total leukocytes (8,2x104 cells.mm-3), Lymphocyte (81.33%) and respiratory burst (0.09 nm) of Tilapia with spore Bacillus supplementation were noted as the highest value. On the other hand, the phagocytosis activity of Tilapia was found statistically similar to vegetative or spore form of Bacillus supplementation. The factor that affected those results was the higher viability of the Bacillus spore in the fish diet. This study indicated that Bacillus supplementation in the form of spore gave the best improvement on the Tilapia non-specific immune response and could maintain the health status of the fish.