Diet, ontogenetic changes and rhythm of feeding activities in Macrobrachium macrobrachion (Herklots, 1851) (Decapoda, Palaemonidae) in the waterbodies and rivers of Benin, West Africa

Knowledge of the diet of Macrobrachium macrobrachion (Herklots, 1851) in its natural environment is a key factor facilitating its successful breeding. We have analysed the stomach content of 452 specimens collected from the Ouémé River Delta (ORD) (338 stomachs) and from the Mono River/Grand-Popo Lagoon complex (MGLC) (114 stomachs), from February to October 2016. The analysis enables to calculate the coefficient of vacuity for the ORD (3.50%) and for the MGLC (3.50%). The results show that M. macrobrachion has a detritivore-omnivore type of diet, feeding mainly on phytoplankton (diatoms and cyanophytes) and detritus. However, the diet of the young shrimps, composed mostly of insect larvae, differs from that of adult. In the adult M. macrobrachion, the pace of feeding activities is greatest in the morning (6.00 to 9.00 am), low in middle of the day (10.00 am to 13.00 pm), and there is a slight trophic activity between 17.00 and 22.00 pm. Outside of the above periods, i.e., from 14.00 to 16.00 pm and 23.00 pm to 5.00 am, the species is at rest. Juveniles feed at dawn. In the nighttime and at dusk, groups of shrimps of varying sizes do feed. The findings of this study suggest that live prey is the best feed for the larvae of M. macrobrachion in captivity and should be distributed preferably early in the morning.

Variable predator–prey relations in zooplankton overwintering in Subarctic fjords

Zooplankton predator–prey relations in northern Norwegian fjords are highly variable in time and space, and the mechanisms driving this variability are still poorly understood. Replicate Juday net sampling in October and February from 1983 to 2005, which included five repeated tows from bottom to surface, was conducted in Saltfjord and Mistfjord, northern Norway. The time-series provided evidence of in situ variability in species abundance, as well as seasonal and interannual changes in standing stock abundance. The shallow sill of one fjord caused accumulation of coastal water in the fjord’s basin, while the other fjord’s deeper sill selected denser water of Atlantic origin from the same open shelf habitat. The selective advection caused differences in the immigration of species recruiting to the fjords’ specific overwintering communities of zooplankton. Statistical analyses of the cumulated replicate data indicated significant in situ variability in the spatial density of species. Cases with an abundance of carnivores relating positively to other species probably resulted from the carnivores’ attraction to patches with concentrations of prey. Interspecific negative density relations likely indicated either predator avoidance or substantial trophic activity during the sampling. During years of high abundance, some wintering stocks of carnivores evidently reduced the local stocks of overwintering prey. We conclude that predator–prey interactions and stock variability in Subarctic fjords result from complex bio-geophysical interactions that occur on the scales of local habitats and basin-scale population systems.

Morphometric study of angioarchitectonic under the effect of opioid (experimental study)

Opioids are potent drugs that are widely used to combat pain in severe wounds and in cancer patients. The professional literature provides a limited amount of data on the morphometric analysis of the links of the hemomicrocirculatory bed of the cerebellar cortex and choroid of the eyeball under the influence of an opioid in the experiment. The aim of the work was to establish the features and conduct morphometric studies of the links of the hemomicrocirculatory bed of the cerebellar cortex and choroid in normal conditions and under conditions of 6-week exposure to an opioid in the experiment. The experimental study was carried out on 24 male white rats, 3 months old and weighing 160-180 g. The material for the study is represented by preparations of the choroid and cerebellum with an injected vascular bed. Compared with the control group of animals, profound destructive changes in the angioarchitectonics of the choroid and cerebellar cortex were found under the influence of Nalbuphine. The capillary component is destroyed, the arterioles are tortuous, sclerosed, their lumen is uneven, the wall is thickened, the venules are dilated and deformed. A decrease in comparison with the norm in the diameter of arterioles, the density of the network of exchange vessels, arterio-venular coefficient, as well as an increase in the diameter of venules and an indicator of trophic activity of the tissue. Expansion of arterio-venular anastomoses indicates the discharge of blood from the arterioles into the venous bed, bypassing the destroyed capillaries. A pronounced relationship was established between the depth of structural transformations of the hemomicrocirculatory bed of the cerebellar cortex, choroid of the white rat’s eye and morphometric parameters. It has been confirmed that the triggering mechanism of destructive changes under the influence of narcotic analgesics is the development of angiopathy.

[Trophic activity of Vulpes vulpes in a wetland: which effects on the reproductive biology of Ardea purpurea?]

[In an Ardea purpurea colony regularly monitored from 2004 to 2018, some predatory events of Vulpes vulpes have been observed since 2010. This was followed by a reduction in the reproductive success and in the number of breeding pairs. Some herons likely abandoned their nests in the reed bed and moved to nesting on trees. The Authors discuss the possibility that these events were a consequence of the predatory activity of the red fox.] [Article in Italian]

Low molecular weight compound GSB-106 mimics the cellular effects of BDNF after serum deprivation

The in vitro model of serum deprivation shows that the survival of SH-SY5Y neuronal cells is ensured by the intrinsic trophic activity of BDNF loop 4-th mimetic GSB‑106 (10-7 М), which is comparable to that of endogenous neurotrophin (10-9 М). The analysis of the cell cycle and S‑phase showed that GSB‑106, like BDNF, induces cell cycle arrest in the G1 phase, diminishes the number of cells in the S‑phase, reduces the number of apoptotic cells and does not stimulate proliferation.

Trophic selectivity of litter saprophages (Diplopoda, Isopoda) in natural forests in the steppe conditions

The forest litter serves as a bridge between the above ground forest flora and fauna with the soil. Trophic activity of soil invertebrates affects the decomposition processes of plant organic residues and, thus, on the forest soils fertility. It is a natural mechanism that positively influences on maintenance and improvement of natural soils properties. The object of this study is the representatives of Diplopoda Rossiulus kessleri (Lohmander, 1927) and Isopoda Porcellio scaber (Latreille, 1804). The aim of the paper is to qualify the trophic preferences of the saprophages, as soil invertebrate representatives, of natural forest ecosystems in conditions of the steppe zone of Ukraine. To identify the ecological role of millipedes and woodlice as primary destructors of leaf litter, we made a field experiment studying their trophic preferences with the use of microcosms. Microcosms (containers) were filled with soil free from invertebrates; after it added a certain mixture of leaf litter and saprophages representatives. To analyze the decomposition rate of leaf litter the percentage of consumed litter was determined by calculating air-dry mass of leaf litter in the beginning and at the end of experiment. A regression model that reflects the trophic selectivity of saprophages for the following mixture components of such tree species as the common maple (Acer campestre (L.), little-leaved linden (Tilia cordata (Mill.), common oak (Quercus robur (L.), European white elm (Ulmus laevis (Pall.), European ash (Fraxinus excelsior (L.) is proposed. Among other regression model types (linear, quadratic, special cubic), permissible statistical estimates revealed a special cubic mathematical model and it allowed to conclude on the saprophages trophic selectivity. The special cubic regression model has a relatively high performance (the determination coefficient is 87.5 %) and adequately approximates empirical data with a significance level of less than 0.05. It was found out that common maple and European white elm litter is consumed in a greater quantity than any other litter from suggested. It is confirmed by their main effects coefficients in the regression equation. Thus, the saprophages trophic selectivity persistence in natural forests under the conditions of the steppe zone has been proved. Consequently, the saprophages trophic activity increases with the presence of the maple and European white elm in natural forests, which makes expedient the use of these tree species, in the design of forest stands.

[Birds trapped in telephone wiring system]

[Six cases of birds trapped in telephone wires or in structures connected to telephone wires were signaled in the areas of Turin and Novara (Piedmont, N. W. Italy). The birds stayed hanging fatally either by chance or during a trophic activity. The species involved in the described episodes are five, but become eight when added to the ones subjects of previous signaling: Little bitten Ixobrychus minutus, Grey heron Ardea cinerea, Moorhen Gallinula chloropus, Barn owl Tyto alba, Little owl Athene noctua, Robin Erithacus rubecula, Starling Sturnus vulgaris, Hooded crow Corvus corone cornix.] [Article in Italian]

MORPHOLOGICAL REORGANIZATION OF THE RATS SUBMANDIBULAR GLAND AFTER 2 AND 4 WEEKS OF EXPERIMENTAL STREPTOZOTOCIN-INDUCED DIABETES MELLITUS

This article represents the results of studying the morphological features of the submandibular gland in 40 male rats during experimental streptozotocin-induced diabetes mellitus at the end of 2 and 4 weeks. Destructive changes of parenchymal and stromal elements in the submaxillary salivary glands of white rats and the vessels of the microvasculature were determined beginning from 2 weeks with the increase to 4 weeks of experimental diabetes mellitus. There is a statistically reliable decrease in the diameter of the organ artery, an increase in the index of the trophic activity of the submandibular gland tissue, and decrease in the packing density index of the capillaries. Reliable decrease of the diameter of the interlobular arterioles, the diameter of the intralobular (front capillary) arterioles and capillaries is observed. These changes are confirmed by morphometric parameters: a statistically evidenced narrowing of the diameter of the organ artery was observed to (62.50±3.30) μm, an increase, in comparison with the norm and control, to the index of the trophic activity of the submandibular gland to (58.27±0.71) μm, and decrease in the packing density of the capillaries to (72.00±6.33) μm. A reliable narrowed diameter of the interlobular arterioles to (31.60±1.61) μm, the diameter of the intralobular (per-capillary) arterioles to (18.04±0.28) μm and capillaries to (5.14±0.09) μm was observed. A little dilatation of post-capillary venules to (23.52±0.43) μm was observed. After 4 weeks of the experiment, the rate of disrupt of the angiographic relief of the submandibular gland arise, and the arteries and arterioles remain narrowed. In some places, the formation of shaped elements beyond the border of capillaries is present. Compared with the previous stage of the research, a mild dilatation of the diameter of the organ artery up to (70.06±2.43) μm, dilatation of the diameter of the interlobular arterioles to (36.06±1.01) μm and the diameter of the intralobular (front capillary) arterioles up to (18 26±0.64 μm, the dilatation of the diameter of the capillaries to (5.71±0.13) μm, the control (5.91±0.19) μm and the dilatation, compared with the norm and control, post-capillar venules to (26, 35 ± 0.50) µm were determined. The index of the trophic activity of the gland tissue decreases as compared with the indication for 2 weeks during the experiment to (58.27±0.71) μm and the capillary packing density gradually decreases to (65.8±1.84) μm. Thus, under conditions of streptozotocin-induced diabetes mellitus, the first structural changes in the bloodstream occur after 2 weeks are observed: a statistically significant decrease in the diameter of the organ artery, an increase trophic activity of the submandibular gland tissue and decrease in the capillary packing density in comparison with the norm. A reliable decrease in the diameter of the interlobular arterioles, the diameter of the intralobular (front capillary) arterioles and capillaries is observed. At the same time, a mild dilatation of post-capillary venules occurs. Interlobular arterioles become anfractuous, have an uneven color. After 4 weeks of the experiment, the temp of disrupt of the angiographic relief of the submandibular gland arise, and the arteries and arterioles remain narrowed. In some places, the formation of shaped elements beyond the border of capillaries is observed.