Search

It is well known that during the suckling period pancreatic secretion is low. The aim of the study was to investigate the effects of dietary supplementation with pancreatic-like enzymes of microbial origin (PLEM) and SiO2, as an antibacterial factor, on the performance of piglets fed creep feed during weaning and thereafter. The experiment was performed on piglets from 30 litters. The piglets were divided into 5 groups (n= 63–66) and weaned at the age of 28 d old. The control group received standard creep feed (Days 7–28), and groups P1 and P2 and groups PA1 and PA2 received creep feed with SiO2supplemented with protease (P1 and P2) or with protease+amylase (PA1 and PA2) during Days 7–13 (P1 and PA1) or Days 14–20 (P2 and PA2) before weaning. Dietary supplementation with PLEM and SiO2led to a significant (P< 0.05) increase in ADG in the treated piglets compared to the control with the best results obtained in group P2. To summarize, creep feed supplemented with PLEM improves productivity parameters of piglets under standard rearing conditions.

Positron lifetime diagnostics was used to study manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) acetylacetonates, γ-chloro and γ-bromo chelate complexes of cobalt and nickel, and similar halo and nitro chelate complexes of copper. The dependences of the annihilation lifetime τ2on the metal nature and the stability constant of the metal chelate ring were established. The annihilation lifetime and intensity were found to depend not only on the electronic effect of the γ-substituent in the chelate ring but also on the structure of the complex. A comparison of the dependences of the frequencies of the C-O and M-O stretching vibrations on τ2revealed that a positron interacts simultaneously with the γ-carbon atoms and the O atoms of the chelate ring, whose accessibilities are determined by the structures of bis(chelates). The plots of the ionization potentials of the n-orbitals of the bis(chelates) vs. τ2were similar to the plots of the quenching rate constant of the benzophenone triplet vs. τ2in the presence of the bis(chelates).Positron lifetime diagnostics was used to study manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) acetylacetonates, γ-chloro and γ-bromo chelate complexes of cobalt and nickel, and similar halo and nitro chelate complexes of copper. The dependences of the annihilation lifetime τ2on the metal nature and the stability constant of the metal chelate ring were established. The annihilation lifetime and intensity were found to depend not only on the electronic effect of the γ-substituent in the chelate ring but also on the structure of the complex. A comparison of the dependences of the frequencies of the C-O and M-O stretching vibrations on τ2revealed that a positron interacts simultaneously with the γ-carbon atoms and the O atoms of the chelate ring, whose accessibilities are determined by the structures of bis(chelates). The plots of the ionization potentials of the n-orbitals of the bis(chelates) vs. τ2were similar to the plots of the quenching rate constant of the benzophenone triplet vs. τ2in the presence of the bis(chelates).

This paper was presented in place of one that was to have been given by the late Professor A. G. Khomenko, Director of the Central Tuberculosis Research Institute, Moscow. Professor Khomenko had a long and distinguished career and with his death Russia has lost one of its finest and most active workers in the fight against TB.