Inclusion ofSalicornia ramosissimabiomass in diets for juvenile whiteleg shrimp (Penaeus vannamei) induces favourable but transient effects in the immune and oxidative status
Authors: Ramos-Pinto Lourenço , Marçal Raquel , Barreto André , Laranjeira Adriana , Machado Marina , Fernández-Boo Sérgio , Teixeira Carla , Oliveira Joana , Couto Ana , Dias Jorge , Guilherme Sofia , Veríssimo Ana C. S. , Pinto Diana C. G. A. , Pacheco Mário , Rocha Rui J.M. , Costas Benjamín 
Published: July 2024

The whiteleg shrimp,Penaeus vannamei, is a highly valued and globally produced crustacean species. However, the rising cost of shrimp feed, exacerbated by increasing cereal prices, prompts the exploration of cost-effective and sustainable formulations for shrimp farming. This study investigates the potential ofSalicornia ramosissima, a non-edible biomass co-product, as a substitute for wheat meal in juvenile whiteleg shrimp diets, aiming to create economically and ecologically sound formulations. The present study aimed to assess the impact of incorporatingS. ramosissimainto whiteleg shrimp aquafeeds on various aspects of shrimp development, including growth performance, survival, immune status, and oxidative status. A commercial-like diet was formulated and served as control, whereas four other diets containedS. ramosissimastems or a combination of leaves and seeds, both at inclusion levels of 5% and 10%, in addition to the control diet. Whiteleg shrimps were fed the experimental diets for 31 and 55 days, followed by a bacterial bath challenge to gauge their immune response to pathogens.

At the end of the feeding period, whiteleg shrimps’ growth performance and survival rates remained consistent across all diets. However, whiteleg shrimp fed diets withS. ramosissimainclusion consumed more feed to achieve similar weights to those fed on the control diet, particularly in diets containing leaves and seeds at a 10% inclusion level, likely due to lower digestibility of dry matter, lipids, and energy. WhileS. ramosissimabiomass inclusion did not affect shrimp weight, relative growth rate, or survival, it did lead to higher feed conversion ratios and feed intake, suggesting differences in nutrient digestibility and metabolic utilization. Additionally,S. ramosissimainclusion affected whiteleg shrimps’ overall body composition, particularly moisture and ash content. DietaryS. ramosissimainclusion modulated antioxidant enzyme activity in the shrimp’s hepatopancreas, indicating potential health improvements. The study also observed gene expression changes related to antioxidant enzymes, indicating an overall down-regulation with the inclusion ofS. ramosissima. Despite challenges in feeding efficiency, the inclusion ofS. ramosissima, especially stems, shows promise in reducing feed costs by utilizing a by-product. Furthermore,S. ramosissimainclusion led to subtle changes in certain plasma humoral parameters and hepatopancreas gene expression. Although some immune parameters varied, these effects appeared to diminish over time. In conclusion, this study highlights the potential ofS. ramosissimaas a functional feed ingredient capable of enhancing shrimp’s antioxidant response, aligning with global resource optimization and sustainability initiatives.