Atresia of ovarian follicles in fishes, and implications and uses in aquaculture and fisheries

Atresia of ovarian follicles, that is the degenerative process of germ cells and their associated somatic cells, is a complex process involving apoptosis, autophagy and heterophagy. Follicular atresia is a normal component of fish oogenesis and it is observed throughout the ovarian cycle, although it is more frequent in regressing ovaries during the postspawning period. An increased occurrence of follicular atresia above physiological rates reduces fish fecundity and even causes reproductive failure in both wild and captive-reared fish stocks, and hence, this phenomenon has a wide range of implications in applied sciences such as fisheries and aquaculture. The present article reviews the available literature on both basic and applied traits of oocyte loss by atresia, including its morpho-physiological aspects and factors that cause a supraphysiological increase of follicular atresia. Finally, the review presents the use of early follicular atresia identification in the selection process of induced spawning in aquaculture and the implications of follicular atresia in fisheries management

Male germ cell proliferation and apoptosis in sexually immature meagre Argyrosomus regius (Asso, 1801) treated with recombinant follicle stimulating hormone

The meagre Argyrosomus regius (Asso, 1801) is a marine fish species that has an increasing aquaculture production in Europe. Lowering the age at maturity of hatchery-produced juveniles would support meagre aquaculture by reducing time between generations in selective breeding programs and reducing industrial costs for broodstock maintenance. The aim of this work was to assess the effects of a treatment with recombinant follicle stimulating hormone (rFsh), produced in ovarian cells of Chinese hamsters, on male germ cell proliferation and apoptosis in sexually immature meagre. The rFsh-treated fish had higher gonadosomatic index, larger seminiferous tubules, more abundant luminal spermatozoa, a lower density of anti-PCNA positive single A spermatogonia, a higher density of anti-PCNA positive spermatocysts and a lower incidence of germ cell apoptosis than control groups. The present study demonstrated the effectiveness of the produced rFsh in stimulating testis development and spermatogenesis in pre-pubertal meagre. Moreover, the rFsh treatment proved to be highly efficient in removing the apoptotic block of spermatogenesis observed in juvenile meagre, allowing spermatogonial survival and progress towards meiosis. The administration of rFsh did not stimulate spermatogonial self-renewal, a process whose control still needs to be elucidated.info:eu-repo/semantics/publishedVersio

Effect of rearing system (free-range vs cage) on gut and muscle histomorphology and microbial loads of Italian White breed rabbits

Objective The growing consumers’ interest on animal welfare has raised the request of products obtained by alternative rearing systems. The present study was conducted to assess the influence of housing system on gut and muscle morphology and on microbial load in rabbits reared under free-range (FR) and cage system (CS). Methods A total of forty weaned (35 days of age) male Italian White breed rabbits were allotted according to the rearing system, and at 91 days of age were randomly selected and slaughtered for the morphological evaluation of tissue from duodenum and longissimus lumborum. Morphometric analysis of the villus height, villus width, crypt depth, villus height/crypt depth ratio, and villus surface was performed. The microbial loads on hind muscle was determined by total mesophilic aerobic count (TMAC), Escherichia coli and Enterobacteriaceae; whereas, total anaerobic bacteria count (TABC) and TMAC, E. coli and Enterobacteriaceae was determined on caecal content. Results Rearing system did not interfere with the duodenum and muscle histomorphology in both rabbit groups. Similarly, microbial load of caecal content showed no significant differences on the TABC and TMAC. Conversely, significant difference was found for E. coli strains in caecal content, with the lower counts in FR compared to CS rabbits (p<0.01). Microbiological assay of muscle revealed significant lower TMAC in FR vs CS rabbits (p< 0.05). All rabbit meat samples were negative for E. Coli and Enterobacteriaceae. Conclusion Free-range could be considered a possible alternative and sustainable rearing system in rabbits to preserve gut environment and muscle quality

Administration of a Polyphenol-Enriched Feed to Farmed Sea Bass ( Dicentrarchus labrax

Farmed fish are exposed to a continuous antigenic pressure by microbial and environmental agents, which may lead to a condition of chronic inflammation. In view of the notion that polyphenols, largely contained in fruits and vegetables, are endowed with antioxidant and anti-inflammatory activities, farmed sea bass (Dicentrarchus labrax L.) have been administered with red grape polyphenol-enriched feed. Polyphenols were extracted from the seeds of Canosina Nero di Troia Vitis vinifera and mixed with conventional feed at two different concentrations (100 and 200 mg/kg, resp.). Fish samples collected at days 223 and 273, respectively, were evaluated for intestinal and spleen cytokine release as well as for spleen macrophage (MØ) and melanomacrophage center (MMC) areas and distribution. Data will show that in treated fish decrease of intestinal interleukin- (IL-) 1β and IL-6 and increase of splenic interferon- (IFN-) γ occur. On the other hand, in the spleen reduction of MØ number seems to parallel increase in MMCs. Collectively, these data suggest that polyphenol-administered sea bass generate lower levels of intestinal proinflammatory cytokines, while producing larger amounts of spleen IFN-γ, as an expression of a robust and protective adaptive immune response. Increase of MMCs corroborates the evidence for a protective spleen response induced by feed enriched with polyphenols

The observed oogenesis impairment in greater amberjack Seriola dumerili (Risso, 1810) reared in captivity is not related to an insufficient liver transcription or oocyte uptake of vitellogenin

The greater amberjack Seriola dumerili is an excellent candidate for the Mediterranean aquaculture, due to its large body size and high growth rate, as well as its high flesh quality and commercial value worldwide. For its successful incorporation in the aquaculture industry, an in-depth understanding of the reproductive function of the species under rearing conditions is necessary, since completion of oogenesis in captivity is currently a bottleneck for the commercial production of the species. Liver and ovary samples from wild and captive-reared greater amberjack females were collected at three different phases of the reproductive cycle: early gametogenesis (EARLY, late April-early May), advanced gametogenesis (ADVANCED, late May-early June) and spawning (SPAWNING, late June-July). The cDNAs of three vitellogenins (VtgA, VtgB and VtgC) were partially sequenced and a qRT-PCR for their expression was used to compare ovarian maturity stage and liver vitellogenin transcript levels between wild and captive-reared individuals. An extensive atresia of late vitellogenic follicles, which prevented any further oocyte development and spawning was observed in captive-reared individuals during the ADVANCED phase. The expression levels of the three vitellogenins, as well as the amount of yolk globules in vitellogenic oocytes, did not differ significantly between captive-reared and wild females, indicating that the observed oogenesis impairment in greater amberjack reared in captivity was not related to an insufficient liver synthesis or a reduced oocyte uptake of vitellogenin

Primi rilievi morfometrici del rene di colombo (Columba Livia).

Il nefrone negli Uccelli si presenta eterogeneo sia nella grandezza che nella struttura. Fondamentalmente abbiamo due differenti tipi di nefroni, con e senza ansa di Henle; i primi sono del tipo dei mammiferi (M) e danno un'urina più concentrata, i secondi sono di tipo rettiliano (R) e danno un "urina meno concentrata (Dantzler e Braun, 1980). Anche nel nefrone degli Uccelli è presente l'apparato iuxtaglornerulare che si associa alle cellule del mesangio. Comunque nessun altro gruppo di vertCbrati mostra un cosi semplice disegno di ansa capillare (Dantzler; 1985) in contrasto con i capillari che noi troviamo anastomizzati nei Mammiferi (Braun, 1982). I reni sono organi simmetrici, destro (dx) e sinistro (sn), suddivisi in tre lobi, pressocchè uguali, per mezzo di scissure trasversali di varia profondità: craniale, medio e caudale. Il parenchirna è formato da lobuli piriformi, con una parte più ampia apicale detta corticale e una più piccola detta midollare. I nefroni M sono meno numerosi e situati in prossimità midollare, quelli R sono in periferia. Nel presente lavoro sono stati comparati il numero e la grandezza dci glomeruli renali di colombi a diverse età e sono stati sottoposti ad analisi statistiche

Ivermectin residues in milk of lactating donkey (Equus asinus): current regulation and challenges for the future

Ivermectin (IVM) is a macrocyclic disaccharide anthelmintic agent with broad-spectrum antiparasitic action. It is used for controlling internal and external parasites in food-producing animals (bovine, swine and equine species), including donkey. This drug is included in Council Regulation (EEC) 2377/9, annex I, with Maximum Residue Limit (MRL) ranging from 15 to 100 μg kg−1 depending on the species. The pharmacokinetic characteristics of IVM mainly depend on the animal species, formulation and route of administration. Due to its high lipophilicity it accumulates in milk of food producing animals. Detailed IVM pharmacokinetic studies were carried out for horse, pig, cattle, sheep, and goat, but there is lack of information for asinine species. Consequently, the absence of “label milk withdrawal time” and MRLs in donkey’s milk indicates that IVM should not be used in lactating animals. On the contrary, information about IVM residues in milk would be of paramount importance in view of the fact that donkey’s milk is a suggested substitute for infants suffering from hypersensitivity to cow’s, sheep’s and goat’s milk protein or from multiple hypersensitivity. European legislation does not explicitly state that an MRL should be determined for every target species; however it’s interpretation led to MRLs being adopted for each species and each foodstuff. Although IVM is approved for use in all lactating animal species the possibility of an illegal use should be considered. In this paper, the problems arising from IVM administration in lactating donkey are analysed. A particular attention is paid for the existing legislation and some proposals are suggested for regulatory framework formulation