Effects of dietary Lithothamnium organic mineral on Pacific white shrimp, Penaeus vannamei, raised in low salinity water synbiotic system

Abstract

This study aimed to evaluate the Lithothamnium organic mineral in the diets of Penaeus vannamei in low-salinity water with a synbiotic system. Two diets were formulated by partially replacing inorganic minerals (calcium, magnesium, and potassium) with a commercial source of Lithothamnium at levels of 2% (LT2) and 4% (LT4) per kg of diet, and two more diets were prepared using the same levels: 2% (CTLT2) and 4% (CTLT4) of Lithothamnium per kg of diet, fixed onto the pellets using a commercial binder. The experiment was conducted for 50 days with a stocking density of 50 shrimps (3.1 g) per m² in a low-water salinity synbiotic system. Different doses and application forms affected the activities of digestive enzymes (trypsin, chymotrypsin, leucine aminopeptidase, amylase, and lipase) in the shrimp hepatopancreas. The oxidative stress enzymes did not differ significantly between the times analyzed, but MDA at 25 days of culture showed different values between LT2 and LT4 treatments compared to CTLT4. The shrimp's proximate and mineral composition showed that the concentration of lipids was lower in the CTLT2 and CTLT4 treatments, while the concentration of calcium was higher in the CTLT4 treatment. The LT2 treatment has a significant difference in shrimp performance (final weight, weekly growth, yield, and FCR) and a higher return on investment (34.26) compared to the other treatments and the control. Based on these results, the Lithothamnium organic mineral addition in diets for Penaeus vannamei for optimal growth was 2% addition (LT2) in the shrimp feed.