The Responses of Penaeoid Shrimp to Vitamin D: Histology of midgut gland.

FENUCCI, J.L; PEREIRA N.D.A; FERNÁNDEZ GIMENEZ, ANALIA VERÓNICA

Veracruz

Congreso; World Aquaculture 2009; 2009

World Aquaculture Society

The prawn Artemesia longinaris and shrimp Pleoticus muelleri are the most abundant penaeoid species in the Argentine coastal waters. As the availability of the two species undergoes yearly fluctuations, it is important to establish the feasibility of culturing. Diet quality is an important condition for a successful culture of crustaceans. Numerous studies have revealed that fat-soluble vitamins are essential in most animals for normal health and life functions. Vitamin D play important role in calcium metabolism, lack of this nutrient was correlated with a decrease in alkaline phosphatase activity in crustaceans. The response of midgut gland of argentine prawn and shrimp fed with diets containing different levels of vitamin D was studied in the present work. Three semi purified diets (vitamin free casein, manioc starch, squid protein concentrate and vitamin free fish oil) were designed containing 0 (D0); 3,000 (D3) and 8,000 (D8) UI vitamin D/kg diet. Prawns (4g mean weight) and shrimps (3g mean weight) were obtained from a commercial fisherman and placed in 150 l glass aquaria (33salinity, 18pH 7, 11:13 h photoperiod). Each diet was tested in three replicate groups of 8 prawns during 9 weeks. At the end of trial specimens in intermolt stage were placed on ice and midgut glands were dissected, fixed in Davidson fluid for 24 h, dehydrated in a progressive series of ethanol and embedded in butylparaffin and paraffin. Sections of 5 were stained with hematoxylin-eosin. Midgut gland from prawns fed with D3 and shrimp fed with D8 exhibited normal histology and the cell types (R, F and B) were well preserved and having a conspicuous brush border. In A. longinaris fed diet D0 and D8, the epithelial cells showed signs of shrinkage and the lumina were enlarged in the affected tubules. Apical cells desquamation, damaged basal lamina and in some cases hypertrophy, haemocytic infiltration and protein precipitation in the intertubular space are also observed. Similar histological results were observed in P muelleri fed with D0 and D3 but were not observed haemocytes infiltration and cellular hypertrophy and necrosis were most evident. The damage caused to the midgut gland was not reflected in the general condition of the prawns and shrimps. Vitamin requirements differ among distinct shrimp species probably due to specie-specific differences. Several authors have asserted that vitamin D is important in diet of shrimps however histological studies are not yet available. In previous study was determined that 2,000 IU vitamin D/kg diet is sufficient for normal growth of Litopenaeus vannamei. In present work according to the histological analysis of midgut gland, A. longinaris has a requirement of 3,000 IU/kg diet and P. muelleri 8,000 IU/kg diet. These results allow concluding that the vitamin D is essential nutrient for Artemesia longinaris and Pleoticus muelleri to maintain the normal functional state of the studied species.