Digestive enzyme ratios are good indicators of hatchling yolk reserve and digestive gland maturation in early life stages of cuttlefish Sepia officinalis L.: application of these new tools in ecology and aquaculture.

In Sepia officinalis (Linnaeus, 1758), the digestive gland matures during the first month post-hatching, while a shift from intracellular acid to extracellular alkaline digestion occurs. The purpose of this study was to investigate the possibility of using enzymatic ratios for the description of digestive system maturation in early life stages of S. officinalis. Second, it is intended to apply these new tools as eco-physiological indicators for understanding the impact of cuttlefish eggs' life history from different spawning sites of the English Channel on digestive performance of juveniles. An experimental rearing was performed over 35 days after hatching (DAH) on juveniles from wild collected eggs in 2010 and 2011. Four digestive enzyme activities and their ratios [i.e., trypsin, cathepsin, acid (ACP), and alkaline (ALP) phosphatase, ALP/ACP, and trypsin/cathepsin] were studied along with histological features (e.g., internal yolk surface and digestive gland development). The two enzyme ratios were good indicators of digestive system maturation allowing the study of the digestive gland's development. They were highly correlated to juveniles' weight increase and histological features of the gland in early DAH. These ratios described more accurately the shift occurring between the intracellular acid and the extracellular alkaline modes of digestion in S. officinalis and were more specific than separated enzyme activities. Their application as eco-physiological tools revealed that enzyme ratios reflected yolk content and digestive gland development in new hatching juveniles. Finally, ALP/ACP ratio was shown to be a powerful tool to describe growth performance of S. officinalis which is useful for aquaculture optimization.

Differential bioaccumulation behaviour of Ag and Cd during the early development of the cuttlefish Sepia officinalis.

Cuttlefish eggs were exposed to background concentrations of dissolved Ag and Cd, using the radiotracers (110m)Ag and (109)Cd. At different time of the embryonic development (50 days), some eggs were placed in non-contaminating conditions. During the experiment, the uptake and depuration kinetics, and distribution of these metals among the egg compartments (i.e. eggshell, vitellus, peri-vitelline fluid and embryo) were assessed. In parallel, experiments were conducted with sub-lethal concentrations of stable Ag and Cd (2 and 1 microgl(-1), respectively) to compare the metal behaviour at higher concentrations. From the spawning date up to 1 month of development, both metals were taken up efficiently by the eggs, reaching load/concentration ratio (LCR) of 1059+/-75 and 239+/-22 for (110m)Ag and (109)Cd, respectively. From this time onwards, (110m)Ag activity continued to increase in eggs, whereas (109)Cd kinetics displayed a significant decrease. Whatever the developmental stage, Cd was mainly associated with the eggshell all along the exposure experiment. In addition, both stable Cd concentrations and (109)Cd LCR remained low in the embryo all along the embryonic development, indicating that the eggshell acted as an efficient shield against the penetration of this metal. In contrast, (110m)Ag passed through the eggshell from day 30 onwards and was then accumulated in the embryo, which contained more than 40% of the whole egg metal burden at the end of the exposure period. In depuration conditions, it is noteworthy that Ag continued to accumulate in the embryo indicating translocation processes from the eggshell and a high affinity of the metal for the embryo tissues. Overall our results showed that at day 30 of the embryonic development the cuttlefish eggshell becomes permeable to Ag but not to Cd. Exposure to stable metals confirmed the saturation capacities of the eggshell for Cd and the Ag penetration properties.

Preliminary study of the effects of commercial lactobacilli preparations on digestive metabolism of juvenile sea bass (Dicentrarchus labrax).

Two forms of the same commercial product (SORBIAL, Allonnes, France), one with live bacteria (PSA) and the other with heat-inactivated bacteria (PSI), containing a mixture of 2 strains of lactobacilli and their growth medium were tested as a diet complement for juvenile sea bass (Dicentrarchus labrax) during a 103-day experiment. In addition to zootechnical parameters (survival, growth, conformation), some effects on digestive metabolism were studied, including enzymatic, ultrastructural and microbial aspects. Microbial preparations improved survival rate. The ventral, dorsal and operculum malformations which usually occur in juveniles did not appear in those receiving PSA and PSI. Furthermore, they stimulated, but not constantly, trypsin and acid phosphatase activities. Intestinal ultrastructure showed an increase in the number of endocytosis vesicles at the apical pole of enterocytes in fishes receiving enrichments. Bacterial flora was not modified in terms of quantity, especially the lactic acid bacteria counts, which were not changed in fishes receiving live lactobacilli (PSA). The mode of action of these multiple beneficial effects appears complex and could be caused by different molecules inside the bacterial cell or excreted into their medium.

Reversible antispermatogenic and antifertility activities of Mondia whitei L. in male albino rat.

Chronic administration of Mondia whitei L. root bark extract (400 mg/kg/day) for 55 days caused testicular lesions resulting in the cessation of spermatogenesis, degenerative changes in the seminiferous tubules and epididymides. The wet weight of the seminal vesicle increased, whereas the weights of testes, epididymides and ventral prostate were unchanged. The treatment also resulted in a partial antifertility effect, and an increase in the protein content of the testes and epididymides. The cholesterol contents of the testes were significantly elevated after 55 days, whereas testosterone and 17beta-oestradiol contents of the testes were unchanged. Serum protein was elevated but serum testosterone was unchanged. A recovery period resulted in normal spermatogenesis and fertility, suggesting reversible antispermatogenic and antifertility effects of the plant.

Effects of aqueous extracts of Hibiscus macranthus and Basella alba in mature rat testis function.

Mature male albino Wistar rats (180-220 g) were given by gastric intubation Hibiscus macranthus Hochst A ex Rich (Malvaceae) and Basella alba L. (Basellaceae) aqueous extract from both fresh and dry leaves, at a dose equivalent to 0.720 or 0.108 g of plant, respectively per kg body weight. This was to evaluate their effects on male reproductive function. Control groups were treated equally, but given water instead of the extract. After the treatment periods, animals were killed, their blood collected, the testes and some annex glands removed for histological and biochemical analysis. Results showed that the extract from fresh leaves significantly increased the body weight of rats by 17% from day 7 as compared to controls, whereas the increase was less pronounced (4%) when the rats were given dry leaf extract. The weight of seminal vesicles of rats given the extracts also increased after 15 days. The histological analysis of testis showed abundant spermatozoa in the lumen of the seminiferous tubulus from day 7 in rats fed with the extract when compared to the controls. The serum level of testosterone was significantly increased on the 15th day by 80% in rats given both types of extracts compared to the controls. Testis of treated rats showed high testosterone production in vitro (136 and 62%, respectively for treated and control after 15 days, compared to those of 3 days). Activity of prostatic acid phosphatase was high in prostate, testis and serum of treated rats in all experimental period. From these findings and observation, it was concluded that the aqueous extract of H. macranthus and B. alba had anabolizing and virilizing effects.