Effect of choline chloride as an osmoregulator as well as its role in growth and the biochemical content of postlarval kuruma shrimp; Marsupenaeus japonicus (Bate).

A 45-day feeding experiment was conducted to examine two levels of dietary choline chloride ( CC) [0.6 and 1.2 g kg−1 CC] against control (0.0 g kg−1 CC) on the biological, biochemical composition and stress tolerance of postlarval (PL-20) Marsupenaeus japonicus. The results showed improvements in some biochemical contents such as phosphatidylcholine ( PC) and methionine (Met) as 0.6 and 1.2 g kg−1 dietary CC significantly ( P < 0.05) increased both PC and Met contents of shrimp carcass more than those of the control group. The results also showed that supplemental (0.6 g kg−1) choline could improve ( P < 0.05) PC/ PE (phosphatidylethanolamine) ratio. Growth parameters of the shrimp group that received 0.6/1.2 g kg−1 dietary CC showed a significant ( P < 0.05) improvement. In case of osmotic stress test, 0.6 g kg−1 supplemented CC level showed significantly ( P < 0.05) longer LT-50 (the lethal time needed to kill half of the population) than the other shrimp groups that received 0.0 and 1.2 g kg−1 dietary CC levels. This study showed the efficacy of 0.6 g kg−1 dietary choline to improve the osmotic tolerance of kuruma shrimp as well as growth, survival and biochemical contents of postlarval kuruma shrimp. [ABSTRACT FROM AUTHOR]