Research Article: Study on formulated diet for large yellow croaker (Larimichthys crocea) larvae at the early feeding stage

Most hatcheries in China rely on live prey for successful rearing of fish and shrimp larvae. Besides the high costs, live prey with pathogenic bacteria also increases the risk of contracting foodborne diseases. More than 3.5 billion large yellow croaker (Larimichthys crocea) larvae (total length over 4-centimeters) were raised in 2016. However, no formulated diet is available for replacing live feed in early stages of this croaker so far. In the present study, a new microdiet (Yq) is investigated for rearing croaker larvae at early stages (15 days after hatching). A commercial import diet (Cd) and live prey (Lp) were fed as controls. About 20,000 larvae per tank were hatched from Ningde Fufa Fishery Company in May 4th, 2017. Quality parameters, such as growth performance, survival and three digestive enzyme activities were measured. The survival rate of Yq (58.5%), Cd (51.5%) and Lp (69.6%) exhibited no significant difference (p >0.05). Furthermore, the cost of Yq was only about 23.3% of the cost of Lp. Specific growth rate in Lp was about 8 times higher (p 0.05). The high survival rate and low cost of Yq showed that it is suitable in rearing Larimichthys crocea larvae at the early stages.