Period for Development of Hepatopancreas
Homogeneous period: The starting feeding period of early stage of shrimp (Pl) have freak hepatopancreas function. Metabolism is the main problems during this period while bacterial infections rarely happen. It is most important to reduce the pressure on metabolism and digestion in order to promote growth, development, improve immunity, rich nutrition system, promote proper digestion etc.
Turn liver period: Shrimp after attaining stage (PL25) in grow out ponds, shrimp starts feeding for growth and development of body. But poor development of hepatopancreas affects on fast body growth and weight. This is the vital period for healthy hepatopancreas in shrimp. Diseases are easily occurring such as swelling and atrophy of hepatopancreas with various stress factors.
Envelop period: Envelop period is the mature time of hepatopancreas function with shrimp length 6-8 cm. There are one white protective envelop besides and turn into normal dark chocolate brown color. Shrimp enters into rapid growth period and also hepatopancreas located in the middle part of head region during entire culture. There are many elements related for shrimp feeding besides water quality. The healthy of hepatopancreas is also vital important in various functions for L. vannamei.
Sign of Hepatopancreas in EMS/AHPND:
Whitening of the hepatopancreas, reduction in size of hepatopancreas, dark spots or streaks on the hepatopancreas, Hardening of hepatopancreas, intertubular haemocytic infiltrations among HP tubules, Hepatopancreas(HP) often appears pale to whitish due to loss of pigment, the HP of shrimp is significantly shrunken, small or discolored, Often pale to white hepatopancreas (HP) due to pigment loss in the connective tissue capsule, significant atrophy.(shrinkage) of HP.
The frequent application of antibiotics and too much use of Vitamins are not suitable for shrimp health. This will affect heavy burden & pressure for hepatopancreas. Antibiotics do not only treat diseases, but also produce endotoxins which will do harm for the health of hepatopancreas and intestine. It Is better to avoid strictly antibiotic use in shrimp. The suitable amount of vitamins shall conform to the digestive ability of intestine and the proper proportion.
The all herb extracts will not do well for hepatopancreas and large application also damage to hepatopancreas. The use of high quality herbal extracts can be suitable for protecting hepatopancreas. Feed intake shall be reduced within reasonable dosage. The stop feeding will cause the consume of glycogen and fat in hepatopancreas. Reasonable reduce the feed intake is feasible, but stop feeding is inadvisable.
Control Measures for Protection to Hepatopancreas in Shrimps
(source: Functionary Properties of Hepatopancreas in Shrimp & Its Protection for Success of Culture)