A preliminary evaluation of the San Pedro daisy (Lasianthaea podocephala) tuber powder, as a feed additive on the intensive culture of shrimp (Litopenaeus vannamei) under laboratory conditions

An experimental study was carried out during seven weeks to preliminarily evaluate the effect of the dietary inclusion of powder from the tuber Lasianthaea podocephala, commonly known as the San Pedro daisy or pionilla, as a feed additive on the production parameters, food consumption, and nutritional condition of the white shrimp, Litopenaeus vannamei, intensively farmed under laboratory conditions. Hypothetically, the additive should improve these parameters as it does when used for humans. The powder was included at different levels (0 [Control], 0.2 [T1] and 1 g kg^-1 [T2]) in a commercial shrimp feed. The tuber powder exhibited a free amino acid profile being arginine (8.59 mg g^-1) and glutamine (3.36 mg g^-1) the most abundant. Feed consumption was not influenced by any treatment; however, the survival and the overall production responses were higher in both treatments using the powder (T1 and T2) compared to the control. No significant differences were detected in muscle concentrations of lactate and glucose, although higher protein and lower cholesterol concentrations were observed in shrimp reared in the control. The lower cholesterol concentration of shrimp from the control could be associated to a poor nutritional status. In conclusion, addition of the powder of San Pedro daisy did not improve the feed consumption, but apparently had a positive effect on survival, production response and nutritional status of shrimp. These responses could be associated to an hypothetic effect of some plant components at a nutritional-molecular level, or to a possible antimicrobial effect; however, further specific studies are needed.