Effect of hemoglobin powder substituted for fishmeal on growth performance, protein digestibility, and trypsin gene expression in Litopenaeus vannamei

Recent increases in the price and demand of fishmeal, the primary protein source in shrimp feeds, have caused asearch for alternative protein sources. Hemoglobin powder (HE) is a by-product produced by separating hemoglobin fromplasma of farm animal un-coagulant blood. HE contains high protein content but low lipid content, and thus has highpotential for fishmeal substitution.A six week feeding trial was carried out to investigate effects of HE substituted for fishmeal protein on growth performance,protein digestibility and trypsin gene expression in Pacific white shrimp (Litopenaeus vannamei). Six diets with0%, 12.5%, 25%, 50%, 75% and 100% of HE replacing fishmeal protein were fed four times daily to six groups of shrimp withan average initial weight of 3.53 g/shrimp. Growth of shrimp decreased with increasing level of HE substitution. Although the12.5% HE substitution caused significantly lower final weight, weight gain, SGR, feed intake, PER and PPV in comparisonwith the control diet, FCR of this diet was not statistically different (p0.05). In-vitro and in-vivo protein digestibility of 12.5% HE substitution were significantly lower than that of the controlgroup in which the trypsin gene expression of shrimp fed 12.5% HE substituted diet was the highest