International Journal of Aquaculture, 2025, Vol.15, No.3, 149-154 http://www.aquapublisher.com/index.php/ija 150 doses and determining the dosage of probiotics and molasses that are good for silkworm maintenance media (Tubifex sp.) in order to meet the need for natural feed containing high protein for fish larvae at BPBAT Mandiangin. 2 Result and Analysis Based on the results of research on cultivating silk worms (Tubifex sp.) for 31 days using different doses in maintenance media at BPBAT Mandiangin. Productivity data, absolute biomass growth and population increase were obtained. 2.1 Productivity Based on productivity in rearing silk worms for 31 days (Figure 1), it shows that in treatment A the highest productivity value was 3.8 kg/m2 and followed by treatment B the productivity value was 3.4 kg/m2. The high value of silkworm productivity in treatment A is due to the dose of probiotics and molasses utilized by silkworms to meet their growth and reproduction needs so that they are more effective in increasing silkworm productivity, in addition to the difference in mud height in the silkworm maintenance media where in treatment A the mud height is 5 cm and in treatment B 4 cm resulting in the distribution of nutrients in the media with a height of 5 cm not being too excessive so as not to cause overfeeding of silkworms. According to Febrianti (2004) in Hidayat et al. (2016) states that providing different doses in the maintenance media will directly affect the organic matter content in the media. The balance of molasses and probiotic doses can increase the availability of organic matter dissolved in the mud accordingly and the composition between probiotics and balanced molasses is what can increase the productivity value for silk worms. The decrease in biomass and productivity of silk worms is caused by the inability of silk worms to absorb the nutrients needed by silk worms to grow and develop too much in the mud so that it cannot be tolerated by silk worms `which ultimately causes death between individuals. In addition to being influenced by the addition of probiotics and molasses, the difference in value is also caused by the difference in mud height in the silkworm maintenance media in treatment A, the mud height is 5 cm and in treatment B 4 cm, it is suspected that this causes the productivity value in treatment B to be low where the low media height with a greater amount of probiotics and molasses can cause nutrients in the maintenance media to be too abundant. The difference in productivity values was caused by the use of molasses and probiotics in treatment A which could be optimized more effectively by the silk worms compared to treatment B with mud media with the addition of 20 mL of molasses and probiotics resulting in the silk worms experiencing an overfeeding condition where the silk worms could not consume nutrients properly. efficient thus affecting the reproduction of silk worms (Tubifex sp.). Figure 1 Productivity of silk worms (Tubifex sp.) in different probiotic and molasses treatments over 31 days 2.2 Absolute biomass growth Based on silk worm rearing activities, it can be seen that the highest biomass obtained in treatment A was 164 grams and in treatment B the biomass was obtained at 130 grams (Figure 2). Treatments A and B experienced
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