Apparent Nutrient Digestibility of Balanced Diets with Soy Bean Extract or Meat and Bone Meal in the Nile Tilapia (Oreochromis niloticus L.) Infected with Vibrio anguillarum


Abstract: Nile tilapia, Oreochromis niloticus L., infected with Vibrio anguillarum or not infected were fed balanced diets containing vegetal (solvent extracted soy bean meal (SBM)) or animal (meat and bone meal (MBM)) protein sources in order to demonstrate the apparent nutrient and energy digestibility. Regardless of protein sources in the diets, feed intake was lower in the infected group. Apparent nutrient (AD_{DM} and AD_{CP}) and energy digestibility (AD_{kJ}) values of Nile tilapia fed the SBM diet were significantly better (P < 0.05) than those fed the CONT and MBM diets and changed little between the measurement days in both groups (non-infected and infected). Although no visible symptoms associated with vibriosis were evident on either the skin or internal organs, the significantly lower (P < 0.05) AD_{DM}, AD_{CP}, and AD_{kJ} values obtained between day 1 and 10 (specifically on days 3 and 10) in the infected group fed the CONT and MBM diets might have implicated the pathogenicity of the bacteria. Further research concentrating on higher amounts of solvent extracted soy bean and meat and bone meal, different environmental conditions and doses of infection with V. anguillarum and immune response parameters including physiological and cellular stress responses is needed in order to identify the overall apparent nutrient digestibility of plant and animal protein sources in Nile tilapia infected with V. anguillarum.

Keywords: Nile tilapia, solvent extracted soy bean, meat and bone meal, vibriosis, digestibility coefficients

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