Valeria Micale

Rice protein-concentrate meal as a potential dietary ingredient in practical diets for blackspot seabream Pagellus bogaraveo: a histological and enzymatic investigation

Field and laboratory studies were conducted to evaluate the intestinal responses to partial replacement of fish meal with rice protein concentrate (RPC) in practical diets for blackspot seabream Pagellus bogaraveo. Two experimental diets were formulated to be isoproteic and isoenergetic with an increasing level of RPC (20 and 35%, respectively) and were tested against a fish meal-based control diet (RPC0). The diets showed similar features for growth performances and both intestinal histology and digestive enzymes. This study confirmed that RPC does not induce intestinal mucosa alterations in this fish. The dietary RPC supplement caused a significant increase in trypsin activity, whereas lipase activity was reduced.

Cholecystokinin in White Sea Bream: Molecular Cloning, Regional Expression, and Immunohistochemical Localization in the Gut after Feeding and Fasting

Background The peptide hormone cholecystokinin (CCK), secreted by the midgut, plays a key role in digestive physiology of vertebrates including teleosts, by stimulating pancreatic secretion, gut motility, and gallbladder contraction, as well as by delaying gastric emptying. Moreover, CCK is involved in the regulation of food intake and satiation. Secretion of CCK by the hindgut is controversial, and its biological activity remains to be elucidated. The present paper addresses the regional distribution of intestinal CCK in the white sea bream, Diplodus sargus, as well as the possible involvement of hindgut CCK in digestive processes. Methodology/Principal Findings Full-lengths mRNAs encoding two CCK isoforms (CCK-1 and CCK-2) were sequenced and phylogenetically analyzed. CCK gene and protein expression levels in the different gut segments were measured 3 h and 72 h after feeding, by quantitative real-time RT-PCR and Western blot, respectively. Moreover, endocrine CCK cells were immunoistochemically detected. Fasting induced a significant decrease in CCK-2 in all intestinal segments, including the hindgut. On the other hand, no significant difference was induced by fasting on hindgut CCK-1. Conclusions/Significance The results demonstrated two CCK isoforms in the hindgut of D.sargus, one of which (CCK-2) may be involved in the feedback control of uncompleted digestive processes. On the other hand, a functional role alternative to regulation of digestive processes may be inferred for D.sargus CCK-1, since its expression was unaffected by feeding or fasting.

Ontogeny and distribution of cholecystokinin-immuno reactive cells in the digestive tract of sharpsnout sea bream, Diplodus puntazzo (Cetti, 1777), during larval development

The appearance and regional distribution of cholecystokinin-immuno reactive cells (CCK-IR) in the developing gut of larval Diplodus puntazzo were studied by means of immunohistochemistry, with the aim of understanding the role of this peptide hormone in the acquisition of digestive capacity. Immunohistochemical reaction showed CCK-IR cells from 10 days after hatching (DAH), near the pyloric sphincter and past the first bend in the midgut, as well as in the hindgut. At 25 DAH CCK-IR cells were scattered throughout the midgut, as well as in the hindgut. Since gastric glands appeared at 30 DAH, CCK-IR cells were most abundant in the anterior midgut, near and including the pyloric caeca, and just afore the ileo-rectal sphincter in the posterior midgut, as well as in the hindgut. In older larvae (39 DAH), CCK-IR cells were mainly distributed in the anterior midgut, including the pyloric caeca, as well as in the hindgut. No CCK-IR cells were detected in the foregut at any stage. The distribution pattern of CCK-IR cells differed from other species which also possess a rotated gut as D. puntazzo. In fact, although cells were abundant in regions where the ingested food is retained, so that they can be stimulated to modulating the release of digestive enzymes, a large number of cells occurred also in the hindgut.

Cholecystokinin: how many functions? Observations in seabreams.

A short overview on the regional distribution of the gastro-intestinal peptide hormone cholecystokin (CCK) in fish is presented. In particular, the results of molecular and immunological studies on seabreams, Diplodus puntazzo and Diplodus sargus, are reported, which, by demonstrating CCK in the hindgut, open new questions regarding the functional role of this hormone in that part of the intestine. The putative involvement of hindgut CCK in the feedback control of digestive processes was tested by measuring CCK gene and protein expression in fed and fasted fish. The results of this study led to hypothesize different roles for the two CCK isoforms in D. sargus, one of which related to regulation of digestive processes from pyloric caeca through hindgut. On the other hand, a functional role alternative to regulation of digestive processes may be inferred for the other isoform.

A Histological Study of Ovarian Development in the Giant Red Shrimp Aristaeomorpha foliacea (Crustacea: Decapoda: Aristeidae) from the Southern Tyrrhenian Sea (Western Mediterranean)

The reproductive features of the giant red shrimp, Aristaeomorpha foliacea, were investigated in the southern Tyrrhenian sea by experimental trawl sampling. The annual length-frequency distribution showed a multimodal trend in females, ranging between 16 and 67 mm carapace length (CL), and a unimodal trend in males (18–45 mm CL). Mature males occurred in different proportions all year round, while females displayed seasonal maturity (June—September), with a peak in July. Six oocyte developmental stages were identified, the most advanced of which (Pv, postvitellogenic) had never been described before in this species. Ovary development followed a group-synchronous pattern, with the yolked oocyte stock clearly separated from the reservoir of unyolked oocytes, suggesting that A. foliacea is a total spawner, with determinate fecundity. Based upon histological findings, a revision of macroscopic maturity staging employed in Mediterranean bottom trawl surveys (MEDITS) is proposed.

Comparative Ontogeny of the Digestive Tract in Sharpsnout Sea Bream Diplodus puntazzo Cetti and Common Pandora Pagellus erythrinus L.

The ontogeny of the alimentary tract and its associated structures (liver, pancreas, gall bladder) was compared between sharpsnout sea bream Diplodus puntazzo and Pagellus erythrinus and some differences were highlighted. The first goblet cells appeared earlier in sharpsnout seabream (5-7 DAH) and later in common pandora (9-11 DAH), as well as taste buds which appeared at 11 DAH in sharpsnout seabream and at 17 DAH in common pandora. On the contrary, stomach segmentation in a cardiac, fundic and pyloric portions was more precocious in common pandora than in sharpsnout seabream, although gastric glands were formed almost simultaneously. Early caecal development was much more precocious in sharpsnout seabream (10 DAH) than in common pandora (22 DAH). At 3 DAH in sharpsnout seabream and later (10 DAH) in common pandora, primordial mucosal folding of intestine began, which appeared well developed in the anterior portion, by 22 DAH in common pandora and by 28 DAH in sharpsnout seabream. The functional meanings of these aspects were discussed comparatively.

Alternative Dietary Sources in Feeding of Blackspot Sea Bream Pagellus bogaraveo (Brunnich, 1768)

The present review reports the results of two studies carried out at the Institute for the Coastal Marine Environment of Messina (Italy) on the suitability of plant-derived raw materials as dietary components for an innovative fish species for aquaculture, black spot sea bream Pagellus bogaraveo. The research focused on the effects of the use of plant (protein/lipid) dietary sources on growth performance, body composition and gastro-intestinal enzyme patterns in nutrient digestion of wild juveniles of P. bogaraveo. In particular, the effect of a total replacement of Fish oil by Echium and linseed oils and a partial substitution of fish meal with a graded level of Rice Protein Concentrate, will be discussed.

Digestive enzymatic patterns as possible biomarkers of endocrine disruption in the red mullet (Mullus barbatus): A preliminary investigation.

During two seasonal trawl surveys (April and October, 2012), red mullet specimens were caught from two sites of the northern Sicilian coast (Western Mediterranean), characterized by different degrees of pollution, to assess whether their digestive enzymes could be cost-effective diagnostic tools for endocrine disruption. Pepsin, chymotrypsin, carboxypeptidases A and B, amylase and lipase were measured in the digestive tract of each fish. During both samplings, significant differences in the digestive enzymatic patterns of fish collected from the two sites were found. In April, pepsin and lipase contents were significantly lower in fish from the most impacted site than in those from the reference site. In October, the enzymatic patterns showed trends different from spring, with controversial results for carboxypeptidases A and B and amylase. Pepsin and lipase patterns suggest a detrimental effect played by organic pollutants and the use of these enzymes as possible biomarkers of exposure to endocrine disruptors.

The Reproductive Biology of Pagellus bogaraveo, a New Candidate Species for Aquaculture

A brief review of investigations carried out at IAMC-CNR Messina on the reproductive biology of farmed blackspot sea bream Pagellus bogaraveo, a new candidate species for aquaculture, is presented. Different aspects of sexuality, including hermaphroditism, gametogenesis, spermatozoal ultrastructure, maturity staging, seasonal development of gonads, and spawning in captivity, were studied. Protandrous hermaphroditism appeared to be the prevalent sexual pattern, although a high incidence of gonochorism occurred. Males were most abundant in smaller size classes and reached sexual maturity at 28.0 cm, while females predominated in the larger size classes and reached maturity at 29.5 cm. The reproductive season lasted from February until April, as in the natural environment. Spontaneous spawning in tank occurred occasionally, whereas approximately 50% of females produced eggs upon stripping. The remaining 50% failed to ovulate, or even to achieve oocyte maturation, indicating an impaired reproductive functionality. A high incidence of oocyte atresia was also recorded. Males produced a small quantity of highly viscous milt, containing only 3% motile spermatozoa. The spermatozoon of P.bogaraveo has an ovoid head, a midpiece containing only one mitochondrion, and a 50.64 ± 4.82 μm long flagellum, inserted perpendicularly and eccentrically into the nucleus.

Analysis and occurrence of some phenol endocrine disruptors in two marine sites of the northern coast of Sicily (Italy)

This study reports the occurrence of some endocrine disrupting chemicals in red mullet samples and sediments collected in two representative sites of the northern Sicilian coast (Italy). For this purpose, an improved method, using solid extraction and high-performance liquid chromatography analyses for the simultaneous determination of bisphenol A (BPA), 4-nonylphenol (4-NP) and 4-t-octylphenol (4-t-OP) in fish tissues and sediments, has been developed and validated. Method performance was demonstrated over the concentration range 0.1-200ng/mL, with detection limits from 0.06 to 0.1ng/mL. Recoveries ranged from 83.4% to 102.6%, with relative standard deviations of 7.7-14.0% for the entire procedure. Results showed that BPA, 4-t-OP and 4-NP were detected in all fish samples and sediments from two sampling sites, indicating that these chemicals have contaminated Mediterranean aquatic ecosystem and have accumulated in fish. The study provided more comprehensive fundamental data for risk assessment and contamination control of phenolic EDCs in aquatic environment.