Protein and cellulose level in diet: Effects on enzymatic activity,metabolite and amino acid profiles in freshwater anomurans Aegla uruguayana (Decapoda: Anomura)

The aims of this study were to evaluate the short‐term effects of artificial diets with different protein: cellulose ratios (D1 = 60:0, D2 = 45:15 and D3 = 30:30) on the enzymatic activity and metabolite profile and to probe the suitability of the amino acid profile of the different diets in Aegla uruguayana. The different artificial diets affected the digestive total protease and amylase activities in a short period of time. Lipases were not affected by the diets. In the haemolymph, an effect of the diet was found in glucose and triglyceride measurements. Particularly, the glucose of the organisms fed D1 was significantly lower than that of organisms fed D2, without significant differences in D3. The concentrations of triglycerides were different among organisms subjected to the treatments, indicating a greater concentration in organisms fed D2 than in those fed D1. In muscle tissue, the concentration of glycogen followed the same trend as haemolymphatic glucose, indicating that the organisms fed D2 had a higher concentration of this metabolite compared to the rest. The amino acid profile of muscle tissue of wild and fed aeglids had a high and significant correlation in all cases, showing few changes in the short‐term feeding regime. Some changes were observed mainly in aeglids fed D3, which exhibited the lowest amounts of methionine, lysine and arginine and the highest amounts of aspartic + glutamic acids. In addition, D2 has a good quality of EAA, fulfilling almost all the requirements of a wild aeglid.     

Use of different geometric morphometrics tools for the discrimination of phenotypic stocks of the striped clam Ameghinomya antiqua (Veneridae) in north Patagonia,Argentina

The striped clam (Ameghinomya antiqua (King, 1832)) metapopulation of the San José Gulf is a good model for phenotypic stocks studies based on the shell shape variation in different fishing grounds. These sites show differences in circulation, tidal currents, coastal topography, and bathymetry. Furthermore, it is known that the diverse environments produce differences in the growth rate of this species. In the current work, we study the shell shape changes in the striped clam from different fishing grounds of the San José Gulf through geometric morphometrics methods. Outlines and landmarks analyses were successful to determinate the provenance of the individuals, with almost the 90% of correct assignations for the most of the fishing grounds. The different methodologies showed variations in diverse morphological traits, and as a result different patterns of the shell shape among localities were evidenced. Moreover, each site presented a typical shell shape. Our results showed that the geometric morphometrics methods are powerful tools to identify and separate intra-specific groups. This approach is applicable to other exploited species with subtle shape variations.     

GENETICS. The Human Variome Project

An ambitious plan to collect, curate, and make accessible information on genetic variations affecting human health is beginning to be realized.     

Influence of seminal plasma during different stages of bovine sperm cryopreservation

This study aimed to evaluate the effect of seminal plasma on bovine sperm cryopreservation and to assess the integrity of plasma and acrosomal membranes, mitochondrial potential, remodelling of F-actin cytoskeleton and sperm chromatin fragmentation during the cooling, equilibrium and freezing/thawing stages. Six ejaculates collected from seven Nelore bulls (n = 42) were used in this study. Each ejaculate was divided into two aliquots (with seminal plasma = SP group; without seminal plasma = NSP group) and packed to a final concentration of 50 × 10⁶ sperm per straw. Statistical analyses were performed using SAS software (version 9.3), and p ≤ .05 was considered significant. A time effect was observed for all sperm characteristics (p < .05), except for chromatin fragmentation (p > .05). The presence of seminal plasma better preserved the acrosomal integrity (SP = 75.2% and NSP = 71.7%; p < .05) and also provided lower F-actin remodelling during cryopreservation process (SP = 29.9% and NSP = 32.4%; p < .05). Regarding to the cryopreservation stages, it was observed that cooling step induced higher remodelling of F-actin than the equilibrium and freezing/thawing stages (56.3%, 32.2% and 23.9%, respectively; p < .05). The equilibrium step had minor influence on overall sperm characteristics while the freezing/thawing stage was responsible for the highest percentage of damage in plasma membrane (−65.2%), acrosomal membrane (−34.0%) and mitochondrial potential (−48.1%). On the other hand, none of the cryopreservation stages affected chromatin integrity. It was concluded that the presence of seminal plasma provides increased acrosomal integrity and reduced remodelling of F-actin cytoskeleton. Higher F-actin remodelling is observed after the cooling step while the freezing/thawing step is most damaging to sperm membranes and mitochondrial potential during bovine sperm cryopreservation.     

Cryopreservation of llama semen using a combination of permeable cryoprotectants

Semen cryopreservation is not available for massive use in South American Camelids (SACs) due to the lack of an efficient protocol and the low pregnancy rates obtained with artificial insemination (AI). The use of a single cryoprotectant (CP) is commonly used in SACs frozen semen. The objective of the study was to evaluate the combined cryoprotective capacity of two permeable CPs at different stages of the cryopreservation protocol in llama semen. Sixteen ejaculates from 4 llama males were analysed, and sperm quality was assayed in raw semen, at 5°C, after equilibration of samples with the CPs and when samples were thawed. The following CPs and combination were used: 6% glycerol (GL), 6% dimethylformamide (DMF) and the combination of both CPs: 3% GL and 3% DMF. A Kruskal–Wallis test and an experimental factorial design, considering one factor with four levels (raw semen, 6% GL, 6% DMF and GL/DMF), were used. Total sperm motility and live sperm with intact acrosomes remained unchanged after equilibration of samples (p > .05). A significant decrease in the percentage of functional membrane, motile and live sperm with intact acrosomes was observed when samples were thawed (GL, DMF and GL/DMF). Nevertheless, the cryopreservation protocols used preserved sperm DNA quality; thus, sperm chromatin condensation and DNA fragmentation were unaffected (p > .05) when GL, DMF and GL/DMF were used. To conclude, no superiority was found between the use of a single or a combination of permeable cryoprotectants to freeze llama semen.