Use of phytase and citric acid supplementation on growth performance and nutrient digestibility of Cirrhinus mrigala fingerlings fed on canola meal based diet

Uso de suplementação de fitase e ácido cítrico no desempenho do crescimento e digestibilidade de nutrientes de dedos Cirrhinus mrigala alimentados em dieta à base de refeição de canola

Abstract

Fishmeal; being a limited and costly feed ingredient is continuously been substituted with locally available plant proteins. However, the occurrence of anti-nutritional factors in plant meal suppresses its potential to be fully replaced. Therefore, in this study we aimed to study the synergistic effects of dietary additives like citric acid and phytase enzyme supplementation on growth performance and nutrient digestibility of Cirrhinus mrigala fingerlings. Canola meal (CM) was used as a test ingredient to replace fishmeal (FM) as; 0%, 25%, 50% and 75%. These four diets were further supplemented by varying levels of phytase (0 and 750 FTU kg^-1) and citric acid (0% and 2.5%) to formulate total sixteen test diets as T₁, T₂, T₃, T₄, T₅, T₆, T₇, T₈, T₉, T₁₀, T₁₁, T₁₂, T₁₃, T₁₄, T₁₅ and T₁₆. Each treatment contained three replicates; applied to fish groups having 15 fingerlings each; following 3×3 factorial arrangement. 1% of chromic oxide was added as an inert marker. Maximum weight gain% (288%) and the lowest value of FCR (1.07) were recorded when fish was fed on diet T₁₂ as compared to fish fed control diet (T₁). Similarly, optimum nutrient digestibility values such as crude protein (77%), crude fat (84%) and gross energy (70%) were noted on same level. It was concluded that 50% canola meal can optimally replace fishmeal when supplemented with phytase and citric acid at the levels of 750 FTU kg^-1 and 2.5%, respectively.

Keywords:
C. mrigala; growth; nutrient digestibility; fishmeal; canola meal