Assessing the bioavailability of the Novel Met-Met product (AQUAVI® Met-Met) compared to dl-methionine (dl-Met) in white shrimp (Litopenaeus vannamei)

This trial was conducted to compare Novel Met-Met product (AQUAVI® Met-Met) and dl-methionine (dl-Met) regarding their availability to juvenile white shrimp. Eleven experimental diets were formulated (Basal, dl-Met 0.06, dl-Met 0.12, dl-Met 0.18, dl-Met 0.24, dl-Met 0.3, AQUAVI 0.06, AQUAVI 0.12, AQUAVI 0.18, AQUAVI 0.24, AQUAVI 0.3), the basal diet was formulated without any additional methionine addition; the other ten diets (dl-Met 0.06, dl-Met 0.12, dl-Met 0.18, dl-Met 0.24, dl-Met 0.3; AQUAVI 0.06, AQUAVI 0.12, AQUAVI 0.18, AQUAVI 0.24, AQUAVI 0.3) were formulated with five graded levels of methionine with two different methionine sources of dl-Met and AQUAVI® Met-Met, respectively. Each diet was fed at a restricted rate to four groups of 30 shrimp for 63 days. The highest value of survival was observed with shrimp fed AQUAVI 0.24 diet, which was significantly higher than that of shrimp fed the basal, dl-Met 0.06 and dl-Met 0.18 (P < 0.05) diets, but without statistical difference with shrimp fed other diets (P > 0.05). The highest values of growth performance (WG and SGR) were observed with shrimp fed AQUAVI 0.12 diet, which were significantly higher than those of shrimp fed the basal, dl-Met 0.06 and dl-Met 0.18 (P < 0.05) diets, but without statistical difference with shrimp fed other diets (P > 0.05). A non-linear exponential regression model indicated that AQUAVI® Met-Met was found to be more bioavailable than dl-Met with calculated relative bioavailability values of 285.8%, 276.4% and 300.4% based on weight gain, specific growth rate and feed efficiency, respectively. These findings lead to the conclusion that differences in bioavailability do exist between sources of synthetic methionine, and AQUAVI® Met-Met is more available than DL-Met for L. vannamei.