Nosiheptide (9671 R.P.) isolated from Streptomyces actuosus 40037 (NRRL 2954) is a sulfur-containing polypeptidic antibiotic, quite different from all the other members of this family. Very active in vitro against gram-positive bacteria, it is inactive in vivo in experimentally infected mice. Not toxic, even at high dose, it may be used as a feed additive for chickens and pigs and it shows a favourable effect on the growth and conversion index.
The MICs of erythromycins A, B, C, and D and some of their derivatives were determined against 21 gram-positive and 15 gram-negative microorganisms. Antibacterial activity was confined to gram-positive and very few gram-negative bacteria. Erythromycin B was somewhat less active than erythromycin A, and erythromycin C and D showed about half that activity or even less. Most other derivatives had negligible activity. Determination of potency by diffusion and turbidimetric assays were in line with MICs. The examination of the results of these assays, however, revealed that there are differences between the data of different laboratories, depending on the microorganisms and conditions used.
The purpose of this paper is to detect any changes in fatty acid and
cholesterol content of goat colostrum in the period of 0-72 hours after
kidding. For that purpose, samples of colostrum from 16 goats, belonging to
local populations in north-eastern Romania where collected. Samples were
preserved by freezing and then subjected to chemical analysis. Preparation of
solutions for fatty acids analysis was based on the principle of methylation,
by combining alkaline methylation (NaOCH3/MeOH) with acid (BF3/MeOH). For
cholesterol we used the principle of fat saponification, using potassium
hydroxide, followed by filtration and separation of cholesterol with hexane.
Detection of cholesterol and fatty acids content was performed by gas
chromatography device. Caprinic acid (C10:0), myristic acid (C14:0), palmitic
acid (C16: 0), stearic acid (C18:0) and oleic acid (C18:1) quantified more
than 75% of the total fatty acids determined 72 hours after birth. Among
short-medium-chain fatty acids, capronic acid (C6:0) was found in highest
proportion (average concentration of 5.7% of total fatty acids), but at the
same time, presented the most obvious oscillation range from 0 to 72 hours
(6.56% at birth, 2.45% and 7.59% from 12 hours to 72 hours), with the
differences between mean values being significant (p<0.05). In the case of
polyunsaturated fatty acids, the ratio between omega 3 and omega 6 was 1/4.64
at kidding and 1/4.23 at 72 hours after birth, the differences being
insignificant. In goat colostrum, the mean concentration of cholesterol was
9.43 mg per 100 g.
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