Crude extract from yellow yam (Dioscorea cayennensis) in in-vitro Lactobacillus spp. assessment, and as a growth promoter in tambaqui juveniles (Colossoma macropomum)

ABSTRACT This study aimed to analyze in vitro growth of Lactobacillus spp. with crude extract from yellow yam (Dioscorea cayennensis; CEYY) at different concentrations (0%, 2%, 4%, 6%, and 8%) and the growth performance and metabolic responses of tambaqui juveniles fed with diets containing different CEYY concentrations (0, 20, 40, 60, and 80 g kg–1). In the in vitro assay, there was no effect on the Lactobacillus spp. growth. The inclusion of 80 g CEYY kg diet–1 increased growth performance, plasma lysozyme activity and intestinal lactate levels. Hepatic glycogen levels were higher with 60 g CEYY kg diet–1. The lipase and nonspecific alkaline protease enzymes displayed the highest activity in the control group. There was no influence on the hematologic parameters, plasma glucose and amylase enzyme. In conclusion, the supplementation of 80 g CEYY kg diet–1 could be indicated for tambaqui, as it improved growth performance, plasma lysozyme and intestinal lactate.