Comparative study on milt quality features of different finfish species

The aim of this research was to study the main sperm characteristics of three different finfish species. Twenty-one gilt- head sea bream (Sparus aurata), 20 brown trout (Salmo trutta, morpha fario) and 15 rainbow trout (Oncorhynchus mykiss) male broodstocks, farmed under optimal conditions for each species and fed standard diets for broodstocks, were manually stripped. Brown trout yielded small amounts of sperm (4.5 vs18.13 ml) that were very concentrated (≅8.5 x 109 vs 1.24 x 109 Szoa/ml) with respect to the other species. The duration of spermatozoan motility for gilthead sea bream sperm was significantly longer (almost 50 min), in comparison to the one-minute motility of Salmonids. Single fatty acids of brown trout sperm were higher than in the other two species for almost all detected fatty acids. In partic- ular, eicosapentaenoic acid (EPA) was at least three times more concentrated in brown trout than in rainbow trout or gilt- head sea bream sperm (1238.3 µg/g vs305.6 and 333.3 µg/g, respectively; P < 0.01). Saturated, polyunsaturated and total unsaturated fatty acid classes were significantly higher in brown trout sperm than in the other two species - almost double with respect to gilthead sea bream sperm and more than double in comparison to RT sperm (P < 0.01)

Effects of vitamin E and phosphatidylcholine on qualitative and quantitative parameters of rainbow trout (Oncorhynchus mykiss) milt

The aim of this work was to investigate the effects of vitamin E and phosphatidylcholine on rainbow trout (Oncorhynchus mykiss) milt. One hundred and twelve rainbow trout (RB) broodstock (2n, 1030± 20g body weight, male:female ratio = 50:50) were fed four isoproteic and isolipidic diets for 110 days. Diets were differing for the type of vitamin premix and phosphatidylcholine supplied: Control (vitamin premix without Vit. E, no phosphatidylcholine); Vit.E (a premix with Vit. E, no phosphatidylcholine); PhC, (vitamin premix without Vit. E, phosphatidylcholine 2.5%); Vit.E +PhC, (vitamin premix with Vit. E and phosphatidylcholine 2.5%). Sperm total volume, in sexually mature males (3+; 966±114g body weight), ranged between 18.57ml (Control) and 34.31ml (Vit. E). Sperm density varied between 1.76x109 Szoa/ml (Control) and 1.16x109 Szoa/ml (Vit. E+PhC), while relative density (related to male body weight) tended to increase with Vit. E (>50x109 Szoa/ml) and to reduce with Vit. E + PhC (85% in all treatments, while motility duration was around 2.37min for Vit. E and Control reached only 0.97min. After overnight storage (+4°C, for 18 hours) motility decreased, 75-80% in gamete motility and 3.39- 56.7% in time motility. PhC dietary supplements significantly increased arachidonic acid contents of sperm with respect to Control (>120 vs 73μg/ g), while Vit. E caused a huge increase in C20:3 n-3 (10.25 vs 2.27ppm). DHA/EPA ratio was significantly lower in Control (>2; p<0.05), while n-3/n-6 ratio was significantly the highest for Vit. E (9.46 vs <7.3)

Tuning the domain wall orientation in thin magnetic strips by induced anisotropy

We report on a method to tune the orientation of in-plane magnetic domains and domain walls in thin ferromagnetic strips by manipulating the magnetic anisotropy. Uniaxial in-plane anisotropy is induced in a controlled way by oblique evaporation of magnetic thin strips. A direct correlation between the magnetization direction and the domain wall orientation is found experimentally and confirmed by micromagnetic simulations. The domain walls in the strips are always oriented along the oblique evaporation-induced easy axis, in spite of the shape anisotropy. The controlled manipulation of domain wall orientations could open new possibilities for novel devices based on domain-wall propagation