Effects of dietary cholesterol on hepatopancreas associated with morphotypic differentiation in male Amazon River Prawns,Macrobrachium amazonicum(Heller, 1862)

Abstract

Cholesterol is a necessary element in the diet of prawns and it is involved in the metabolic processes of sexual maturation and synthesis of the molting hormone.Freshwater prawns are not able to synthesise cholesterol from specialised metabolic pathways. The aim of this study was to describe changes in structural and morphometric patterns of hepatopancreas associated with morphotypic differentiation of males Macrobrachium amazonicum when fed with different levels of cholesterol.Considering the four morphotypes of this species, Translucent Claw morphotype specimens were split into experimental units and divided into four groups, fed with different levels of cholesterol (0%, 0.5%, 1%, 2%) for 50 days. They were collected as they reached Green Claw (GC) morphotype, weighed to determine the hepatosomatic index, and the hepatopancreas was processed in histological routine for morphologic and morphometric analysis. In this study, it was possible to observe that the 2% cholesterol treatment exhibited more animals that reached the GC morphotype, and there was no significant weight gain in all treatments. Histologically, B-cell abundance and hypervacuolized as well as F-and R-cells shortages were observed as the percentage of cholesterol increased. This alteration in cellular profile correlates with the morphometric analyses that exhibited an increase in epithelial area and alterations in the lumen shape. This imbalance observed in the lumen-epithelium relationship may be associated with a low digestive performance and possibly congested the functions of hepatopancreas. Thus, high doses of cholesterol promoted morphotypic differentiation without weight gain, due to alterations on hepatopancreas. K E Y W O R D S

Histology of the hepatopancreas and anterior intestine in the freshwater prawn Macrobrachium carcinus (Crustacea, Decapoda)

“…In M. carcinus, the abundance of F-cells in the distal region may suggest that they originate directly from the E-cells, as well as the R-and B-cells observed in this region. Therefore, in M. carcinus we suggest that the distal region acts in generative and epithelial renewal of the entire hepatopancreatic epithelium, as in M. amazonicum (Heller, 1862) (Franceschini-Vicentini et al, 2009;Ribeiro et al, 2014;Ruiz et al, 2019).…”

“…According to Ribeiro et al (2014), vacuolization in B-cells may suggest the functional stage of these cells. Longo and Diaz (2015) and Ruiz et al (2019) suggest that the various small vacuoles showing scarce acid glycoproteins in the B-cell cytoplasm, would indicate the beginning of the digestion process. On the other hand, the presence of a large vacuole in the cytoplasm indicates the end of the digestive process (Franceschini-Vicentini et al, 2009;Ribeiro et al, 2014).…”

“…Recently, Štrus et al (2019) and Vogt (2019) presented reviews regarding morphology and functional role of epithelial cells in the hepatopancreas with great emphasis on marine species. The morphology of the hepatopancreas provides support for studies on nutritional requirements for the development of sustainable cultivation techniques, as well as knowledge about the biology of the species (Icely and Nott, 1992;Johnston et al, 1998;Franceschini-Vicentini et al, 2009;Díaz et al, 2010;Longo and Díaz, 2015;Ruiz et al, 2019).…”

Differential expression of neuropeptide F in the digestive organs of female freshwater prawn, Macrobrachium rosenbergii, during the ovarian cycle

“…Hence, we discussed the expression and distribution of NPF in related to their possible related functions in the HP. In decapod crustaceans, the HP cells are involved in absorption, nutrient assimilation, waste excretion, and immune response (Ruiz et al 2019 , 2020 ; Vogt 2019 ). In Macrobrachium carcinus and M. rosenbergii , the middle region of the HP tubules is primarily made up of F- and/or B-cells, indicating that these cells may be involved in intense secretion of digestive enzymes for extracellular digestion as well as some intracellular digestion (Sonakowska et al 2015 ).…”

Evaluation ofAgave lechuguillaby‐product crude extract as a feed additive for juvenile shrimpLitopenaeus vannamei

“…The B, F and R cells from shrimp hepatopancreas are cellular types showing high morphological plasticity. For example, the morphometric analysis from the epithelial area and the shape of the lumen of the hepatopancreas tubules in Macrobrachium amazonicum were useful to evaluate structural changes, when fed with different cholesterol levels (Ruiz, Ribeiro, Vicentini, Vicentini, & Papa, ). Moreover, the histological structure of L. vannamei hepatopancreas fed with Streptomyces strains was evaluated by measuring the epithelium height, the tubules total count, atrophy and tubule hepatopancreatic necrosis, showing better histological integrity, with significantly lower degree of atrophy and necrotic tubules, than fed without Streptomyces (García‐Bernal et al, ).…”