Attractability and palatability of formulated diets incorporated with fermented aquatic weeds meal (FAWM) for Asian catfish Clarias batrachus fingerling

Abstract

The inclusion of protein sources from aquatic weeds is limited in the commercial aquafeed industry due to the variability of their nutritional profile, palatability issue, and levels of anti-nutritional factors (ANFs). This research set out to observe the physical, biochemical, and bacteriological properties, as well as the attractability and palatability of various types of fermented aquatic weeds meal (FAWM) treated diets for Asian catfish production. Four experimental diets (30% crude protein) were prepared by replacing 50% protein of control diet with different FAWM and labeled as D₀ (control group), D₁ (fermented Azolla), D₂ (fermented Pistia), and D₃ (fermented Eichhornia). The physical properties of FAWM diets in terms of pellet durability index, bulk density, water stability, floatability, and swelling test showed significant (p<0.05) alterations among the diet groups in this research. The color and flavor of FAWM diet groups were characterized by a greenish-black and brown, along with a strong fermented flavor, while control diet showed typical color and odor. Both total bacteria (TB) and lactic acid bacteria (LAB) were considerably (p<0.05) greater in FAWM groups when those compared to the control diet. The diet containing fermented Azolla (D₁) had remarkably (p<0.05) higher attractability (53.33%) and palatability (14.22 mg/g) than other tested diets. Additionally, the outcomes of taste preference assessment revealed that the fish exhibited a significant (p<0.05) preference for pellets from the D1 diet. Though the significantly higher growth performance and feed utilization were occurred in the Despite the control diet displaying significantly better growth performance and feed utilization, the fish fed with fermented Azolla diet experienced an increased final weight (g), weight gain (%), Specific growth rate (%/day), feed conversion ratio, and protein efficiency ratio amongst the FAWM diet groups. Based on the above findings, it can be concluded that incorporating FAWM, specially fermented Azolla meal could assist in generating low-cost, more palatable, attractable, and high quality aquafeed for Asian catfish production in captivity.