Effective microorganisms (EM) have been proven as a natural remedy for enhancement of growth in livestock and fisheries. The lack of beneficial microbial population in pond water and the fish gut, particularly associated with water change frequency can adversely affect overall fish production. Thus this 60-day experimental study investigated the effects of water-change frequency and Effective Microorganisms (EM) on the growth performance and gut microbiota of Heteroclarias fingerlings. The experiment employed a completely randomized design with three treatments: A (5-day water change without EM), B (5-day water change with EM), and C (10-day water change with EM). Each treatment consisted of triplicate groups of fingerlings (initial mean weight = 4.50 g) at ten fish per 30 L plastic tank. Growth parameters including feed conversion ratio (FCR) and gut microbial diversity were evaluated. Treatment C achieved the highest mean weight gain (11.4 ± 0.95 g; p 0.05) were recorded in specific growth rate (SGR) or feed intake among treatments, EM application markedly enhanced gut microbial composition. The dominance of beneficial bacterial species such as Bacillus subtilis and Bacillus licheniformis in Treatment C, contrast with pathogenic taxa including Enterococcus faecalis observed in other groups. EM inoculation with reduced water-change frequency supports microbial proliferation and low FCR. Integrating EM with a 10-day water-change interval improve growth and water-use efficiency in Heteroclarias.
Oyediran et al. (Wed,) studied this question.