The objective of this study was to evaluate the effect of diets containing different inclusion levels (0, 7, 14, 21 and 28%) of soybean meal fermented by Lactobacillus acidophilus (SMFL) on the zootechnical performance and intestinal bacteria count of South American catfish juveniles (Rhamdia quelen). The experimental design was completely randomized with five treatments and four replications and lasted 56 days.
Five isoproteic (39% crude protein) and isoenergetic (4,300 kcal of gross energy kg-1) diets were formulated where SMFL was included in replacement of fish meal. 240 South American catfish juveniles (3.0±0.5 g) were distributed in 20 tanks (70 liters) connected in a recirculation aquaculture system.
At the end of the experiment the inclusion of SMFL up to 21% in replacement of fish meal did not affect (P>0.05) the weight gain (Figure I.A) and also decreased (P<0.05) the concentration of Vibrionaceae bacteria present in the intestine compared to the control group (Figure I.B). The amount of total lactic and heterotrophic bacteria did not differ between dietary treatments.
The results demonstrate that fermentation with Lactobacillus acidophillus enables greater inclusion of soybean protein in South American catfish diets and promotes the control of intestinal pathogenic bacteria.