Nutritional evaluation of an improved soybean meal as a fishmeal replacer in the diet of Pacific white shrimp,Litopenaeus vannamei

A 12-week growth trial was conducted to assess an improved soybean meal (ISBM) in the diet of Pacific white shrimp (PWS). Four isonitrogenous and isolipidic experimental diets were formulated: the control diet (ISBM-0) contained 30% fishmeal (FM) and three test diets (ISBM-33, ISBM-66 and ISBM-100) were formulated by gradually replacing FM on an isonitrogenous basis. Groups of PWS (3.2 g mean initial weight) were fed their respective experimental diets three times per day. Production performance of PWS was unaffected by diet, except the final weight of shrimp-fed ISBM-66 diet was significantly lower than those fed ISBM-0. Whole-body moisture was significantly higher and protein was significantly lower in PWS-fed ISBM-100 versus shrimp-fed ISBM-0. PWS-fed ISBM-66 had significantly higher oleic acid than shrimp-fed ISBM-0 and linolenic acid versus shrimp-fed ISBM-0 and ISBM-100. The lowest linoleic acid and n-6 polyunsaturated fatty acids levels were found in shrimp-fed ISBM-100. Based on second-degree polynomial regression analysis of final weight and weight gain, the estimated optimum levels of ISBM to replace FM in PWS diets are 89.13% and 95.56% respectively. Overall, results indicate alternative, sustainable, plant-based protein sources such as ISBM may potentially replace FM in PWS diets.