Effectiveness of Acidification and Phytase Pretreatment on Growth Performance, Muscle Proximate Composition and Nutrient Digestibility of Rohu (Labeo rohita, Hamilton 1822) Juveniles Fed Soybean Meal Based Diet

This research project studies the growth performance, muscle proximate composition and nutrient digestibility performance by rohu (Labeo rohita) juveniles fed citric acid (CA) acidified phytase (PHY) pretreated soybean meal (SBM) based diet. Basal SBM based diet was supplemented with two levels of CA (0 and 2%) and two levels of microbial PHY (0 and1000 FTUkg(-1)) in factorial arrangement resulting in the formulation of four experimental diets. Chromic oxide (1%) was added as an inert marker in the diets to evaluate the nutrient digestibility. Important water quality parameters such as temperature, pH and dissolved oxygen were monitored and maintained within acceptable limits for fish during entire experiment. The findings of the experiment showed improved weight gain%, specific growth rate (SGR), feed conversion ratio (FCR), muscle composition and digestibilities of dry matter, crude protein and crude fat in Labeo rohita juveniles when fed CA supplemented diet. Similar observations were also recorded for the group fed on PHY supplemented diet. Citric acid addition in the diet also resulted in improved (p<0.05) digestibilities of Ca, Mg, P, Na, K, Cu, Zn, Fe and Mn. Similarly, PHY pretreatment had also resulted in enhanced mineral digestibility as compare to control group. However, both the supplements did not interact positively (p>0.05) for the observed responses except SGR, FCR and crude ash contents in muscles. It was evident from the present study that soybean meal based diet supplemented with CA and PHY performed better than without supplementation.