LAUSR

Effective microorganisms (EMs) were commonly used to improve water quality in aquaculture, but its use as a fish nutritional supplement has not been investigated. Thus, two experiments were conducted. The first experiment aimed to evaluate the effects of 0%, 2%, and 4% EM-supplemented diets on the growth, hematological, and histopathological parameters on Oreochromis niloticus under two feeding regimens A and B with either 2:1 meal ratio (morning-concentrated diet) or 1:2 (evening-concentrated diet), respectively. EM-fed fish exhibited significantly higher rates of weight gain, specific growth, survival, and feed conversion efficiency mainly in the morning-concentrated diet. WBC count, HGB, and HCT showed significant differential values at different feeding regimens, with the highest recorded with 2% EM diets. Histopathological parameters such as the intestinal perimeter ratio, mucosal fold length, intraepithelial lymphocyte, and goblet cells were elevated exponentially with increased EMs dose. In the second experiment, EM-supplemented diets were assessed for the antiparasitic activity in fish that was experimentally challenged with Trichodina species. Lower infection rates of 28% and 35% were recorded in EM-treated groups at 2% and 4% EM groups, respectively. We concluded that 2% was more efficient than 4% EMs, both for its beneficial health effects and in avoiding the overdosage-associated toxicity risk.