Feeding effect of selenium enriched rotifers on larval growth and development in red sea bream Pagrus major

Feeding trials were conducted to investigate the effect of selenium (Se)-enriched rotifers on growth and development of red sea bream Pagrus major larvae. Fish were reared from fertilized eggs (98% hatch rate) to 20. days post hatch (dph) at 19. °C with two different food sources; non-enriched S-type rotifers (0.0. μg. Se/g D.W., control diet) or Se-enriched rotifers (2.2. μg. Se/g D.W., Se-enriched diet) at 10. rotifers/mL, respectively. On the last day of larviculture, the Se-enriched diet accelerated growth and developmental stage of fish larvae. The larvae fed Se-enriched rotifers were advanced in the following parameters compared to those fed control diet: total length (6.06 vs 5.53. mm), standard length (5.74 vs 5.26. mm), head length (1.46 vs 1.28. mm), eye diameter (0.57 vs 0.50. mm), the number of caudal fin rays (5.8 vs 1.9), and the proportion of individuals undergoing notochord flexion (55 vs 3%). Fish larvae of 20. dph showed higher Se concentration (9.5 ± 0.2. μg/g DW) with the Se-enriched diet than with the control diet (1.3 ± 0.3. μg/g DW), but there were no significant differences in the composition of polyunsaturated fatty acids which significantly affect larval growth and development. Therefore, the feeding of Se enriched rotifers enhanced growth and development of the red sea bream P. major larvae

Recent Developments of Computational Methods for pKa Prediction Based on Electronic Structure Theory with Solvation Models

The protonation/deprotonation reaction is one of the most fundamental processes in solutions and biological systems. Compounds with dissociative functional groups change their charge states by protonation/deprotonation. This change not only significantly alters the physical properties of a compound itself, but also has a profound effect on the surrounding molecules. In this paper, we review our recent developments of the methods for predicting the Ka, the equilibrium constant for protonation reactions or acid dissociation reactions. The pKa, which is a logarithm of Ka, is proportional to the reaction Gibbs energy of the protonation reaction, and the reaction free energy can be determined by electronic structure calculations with solvation models. The charge of the compound changes before and after protonation; therefore, the solvent effect plays an important role in determining the reaction Gibbs energy. Here, we review two solvation models: the continuum model, and the integral equation theory of molecular liquids. Furthermore, the reaction Gibbs energy calculations for the protonation reactions require special attention to the handling of dissociated protons. An efficient method for handling the free energy of dissociated protons will also be reviewed