EFFECT OF EXOPOLYSACCHARIDES PRESENCE ON SENSITIVITY OF
Lactococcus lactis
CELLS FOR BACTERIOPHAGE INFECTION *
Andreja MIKLIČ a) and Irena ROGELJ
a) Univ. of
Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale,
Slovenia, Ph.D., M.Sc.
Original scientific paper
Language: Slovene
ABSTRACT Several lactic acid bacteria produce exopolysacharides (EPS)
with different composition and structure. EPS are believed to play a role in the
protection of the microbial cell against desiccation, phagocytosis, antibiotics
or toxic compounds and phage attack. The effect of EPS of seventeen strains of
Lactococcus lactis, isolated from starter cultures in three Slovenian
dairy plants, on bacteriophage adsorption was studied. In order to determine the
possible influence of EPS presence on bacteriophage adsorption, we treated cells
with different chemical agents. After washing the cells with 25 mM NaOH, most of
isolates were susceptible for more bacteriophages as before. EPS of studied
isolates consisted mainly from galactose, glucose and xylose. The highest
concentration of polysaccharides was detected in PT19 isolate (galactose
130.6 μM and xylose 146.9 μM), which was susceptible only to
FPT19
phage. In the future we will try to confirm the presumption that isolates MB18,
KR7, PT4, PT13 and PT19 produce EPS which mask receptors for phage adsorption.
The article is a part of doctoral dissertation 'Defence of
Lactococcus lactis isolates from dairy plants against phage infection',
issued by Andreja Miklič, supervisor prof. Irena Rogelj, Ph.D.
a), Franc
Viktor NEKREP and Romana MARINŠEK-LOGAR
a) Univ. of
Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale,
Slovenia, M.Sc.
Original scientific paper
Language: Slovene
ABSTRACT
Butyrate is an important probiotic factor that beneficially affects the activity
and survival of colonocytes and exerts an anticarcinogenic activity in the
colon, too. Recently, on the basis of 17 rumen strains a new species P.
xylanivorans
with type strain Mz5T was established. The strain Mz5T
produced butyrate and lactate as major fermentation products and utilized
acetate in the medium with oat spelts xylan. Butyrate production was strongly
increased during the logarithmic growth phase and was still slowly increasing in
the late stationary phase. The rate of butyrate production was similar to other
carbohydrates (birchwood and beechwood xylan, xylose, arabinose and glucose).
The bulk of butyrate with regard to lactate was formed during the early
logaritmic phase regardless of substrate. Therefore, P. xylanivorans Mz5T
could be used as probiotic in animal feed to improve xylan degradation and also
for increased production of butyrate in the colon. The best choice would be a
culture in the early logarithmic phase grown on an inexpensive source of
carbohydrates.
The article is a part of a master of science thesis
'Isolation of highly xylanolytic rumen bacterium and characterization of its
enzymatic system for xylan degradation', issued by Maša Zorec, supervisor
ass. prof. Romana Marinšek Logar, Ph.D.
THE EFFECT OF PERRORALY ADDED CHESTNUT TANNINS ON DAILY GAIN AND
COMPOSITION OF FAECES IN SHEEP AND GOATS
*
Andreja KOMPREJ a), Andrej OREŠNIK,Milan
POGAČNIK and Anton VIDRIH
a)Univ. of Ljubljana,
Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia,
M.Sc.
Original scientific paper
Language: Slovene
ABSTRACT
The effect of extracted tannins from chestnut wood (Castanea sativa
Mill.), which were added to the diet for sheep and goats was studied.
Preparation (Tanin, Sevnica) contained 74 % mainly hydrolysable tannins. 21
young sheep and 10 goats, which grazed at the Karst region, were included into
the experiment. Every three days the amount of 0.5 g preparation kg–1
body weight was applied to thirteen young sheep and five goats. Eight young
sheep and five goats were observed as a control group. All sheep and goats
grazed at the same paddocks on the same pasture. The experiment lasted 68 days.
The average daily gain of the experimental group of sheep was 37 g day–1
and 18 g day–1
of the control group of sheep. The differences in daily gains of the young sheep
were not statistically significant. In the first period (35
days), the experimental group of sheep had less dry matter (189–217 g kg–1vs. 195–229 g kg–1), more crude protein (177–157 g kg–1
DM vs. 170–142 g kg–1 DM) and more tannins (0.77–0.61 % in DM
vs. 0.73–0.52 % in DM) in faeces than the control group of sheep. The
correlation between the tannins and crude protein content in the faeces of sheep
was highly statistically significant (r = 0.92, P < 0.05). Results demonstrate
the effect of added chestnut tannins on the composition of faeces, what is
probably due to the place of digestion of the ingested nutritive substances.
Both groups of goats lost body weight (–79 g day–1). In the faeces of
goats there were more dry matter (192–297 g kg–1)
and less crude protein (108–144 g kg–1 DM)
and tannins (0.24–0.48 % in DM) than in the faeces of
sheep.
The article is a part of master of science thesis 'The effect
of chestnut tannins on protein utilisation in sheep and goats', supervisor
prof. Andrej Orešnik, Ph.D.
EFFECT OF VITAMIN-MINERAL PREMIX ON SOME RELATIONSHIPS BETWEEN
SERUM PARAMETERS IN BREEDING HORSES
Mansur S. HAREADY a)
a)Central Lab. for Food and
Feed, EG-588 Orman, GIZA, Egypt, Ph.D.
Original scientific paper
Language: English
ABSTRACT
Eight Arabian stallions were selected from clinically normal horses. After 10
day adaptation period the animals were divided into two equal groups: control
and experimental. All horses were housed individually and allowed to walk on
sandy paddock twice a day between meals. Both groups were fed the same diet
which was composed of 6 kg hay and 4 kg barley. However, the experimental group
was supplemented with 150 g of micronutrient premix. Premix was composed of
180 g of oats husk meal, 260 g dicalcium phosphate as carrier, 25 g
lignosulphate, 20 g methionine, 20 g lysine, 200 g calcium, 40 g salt (NaCl),
30 g soy oil, 100 g yeast, 50 g mixture of vitamins, 75 g mixture of minerals
and antioxidants per kg. The experiment was divided into adaptation and
experimental period that lasted 10 and 30 days, respectively. The blood was
drawn at the beginning of experimental period and thereafter in 10 days
intervals. Serum samples were analysed for total serum protein, serum urea,
serum lipids, serum glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic
transaminase (GPT). The results showed highly significant differences between
both groups in serum protein, serum lipids, serum GOT and GPT. Significant
difference has been found between both groups in serum urea (P < 0.1). These
changes in serum parameters between groups could be due to the additive
micronutrient premix fed to the experimental groups. The correlations between
parameters: protein and urea was significant negative, between lipids and GOT
highly significant negative, and between lipids and GPT non-significant.
URINE CORTISOL IN PIGS OF DIFFERENT MH-GENOTYPES
*
a), Milena KOVAČ, Jan LADEWIG and Ivan ŠTUHEC
a)Univ. of Ljubljana,
Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia,
Ph.D.
Original scientific paper
Language: English
ABSTRACT Urine cortisol concentration was evaluated in German Landrace
barrows of two MH-genotypes (NN, Nn) housed in metabolic cages. Furthermore,
cortisol in urine was evaluated as a substitute measure of plasma cortisol
values in pigs. Three replicates were done, each including 4 animals. Altogether
there were 12 animals included in the experiment. The
effect of MH-genotype on urine cortisol concentration was evaluated and
correlations between urine and plasma cortisol were calculated.Higherurine cortisol values in NN- in comparison to
Nn-pigs indicated stronger response to stressors by stress resistant
NN-genotype. The correlation between urine (12-hr
urine values) and plasma (the average of 12 collections per day, taken between 8.00 a.m. and 11.00 a.m.) cortisol
values was practically negligible in samples taken on
the same day (r = 0.07, P = 0.71). In time-lag samples (urine taken the day
after blood collection) correlation was increased (r = 0.22), but still not
significant (P = 0.22). A connection between plasma and urine cortisol values
was indicated, but it should be better understood before urine cortisol is used
as a substitute of plasma cortisol measuring in pigs.
The paper presents a part of the results from the Ph.D.
thesis 'The estimation of the degree of stress in
pigs with the evaluation of cortisol concentration in plasma, urine and
saliva', issued by Nataša Siard, supervisor Prof. Ivan Štuhec, Ph.D.
GENETIC PARAMETERS OF
WEANING-TO-OESTRUS INTERVAL IN PIGS
USING BAYESIAN ANALYSIS
a), Milena
KOVAČ and Rainer RÖHE
a)Univ. of Ljubljana,
Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia,
Assist., Ph.D.
Original scientific paper
Language: English
ABSTRACT
Genetic parameters for weaning-to-oestrus interval (WOI) were estimated on
11,026 sows from pig selection farm Ptuj (Slovenia). Univariate analyses of
observations of WOI across parities and two-trait analyses of records of
primiparous (PP) and multiparous (MP) sows were performed applying Bayesian
approach. WOI was analysed on original scale, transformed using a natural log
transformation (lnWOI) and considered as a mixture of normal and exponential
distributions (trWOI). Statistical model included genotype, season of service as
year-month interaction, and parity as fixed effects, and previous lactation
length and number of piglets weaned as covariates. Direct additive genetic
effect and permanent environment were considered as random effects. (Co)variance
components were estimated by Bayesian analyses. Gibbs chains of length between
130,000 and 180,000 were run. Univariate analysis for sows across parities
resulted in heritability estimates of 0.06, 0.07, and 0.07 for WOI, lnWOI and
trWOI, respectively. Permanent environment (PE) accounted for 26 % of phenotypic
variation for WOI and 19 % for both lnWOI and trWOI. In bivariate analysis,
heritability was 0.19 in PP and 0.06 in MP. Genetic correlation for WOI between
PP and MP was 0.80. The PE proportion was 0.10 in MP sows. Based on genetic
parameters, selection on improved rebreeding performance in pigs is expected to
be most efficient considering WOI in primiparous and multiparous sows as
different traits. Transformation of WOI increased the genetic parameters only
slightly.
ASSESSMENT OF LABOUR SUPPLY MOBILITY ON AGRICULTURAL HOLDINGS IN
SLOVENIA IN THE PERIOD 1991–2000 *
Luka JUVANČIČ
a)
a)Univ. of Ljubljana,
Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia,
Assist., Ph.D., M.Sc.
Original scientific paper
Language: Slovene
ABSTRACT
The paper aims in quantitative evaluation of various determinants on labour
supply mobility on agricultural households in Slovenia. Through the use of
longitudinal dataset, quantitative analysis of intertemporal employment
decisions of farm holders is carried out by application of agricultural
household modelling. Two sets of probit models were applied. Functional forms of
the models differ with respect to the predicteded effect of previous employment
status of reference person. Determinants tested refer to personal
characteristics of reference persons (gender, age, education level, opportunity
off-farm income), household characteristics (size, structure), characteristics
of the agricultural holding (economic size, labour input, labour intensity) and
local labour market conditions. Despite specific macroeconomic and structural
conditions, the model results do not differ considerably from the existing
empirical evidence on labour supply dynamics on agricultural households.
Participation of holders at the labour market is neither symmetrical nor
reversible. Results reveal a marked tendency towards upkeeping of the same
employment status, which is more distincted in the case of holders employed on
the farm. A low level of labour supply mobility worsens efficiency of labour
allocation on agricultural holdings. Elements of this problem emerge on both,
supply (e.g. low level of educational and professional attainment of reference
persons) and demand side of labour market (e.g. unfavourable local labour market
conditions).
Key words:agriculture
/ households / labour market / labour supply mobility / agricultural household
models / probit model / Slovenia
____________________
*
The article presents a part of the results from dissertation
thesis 'Modelling of employment decisions on farm households in Slovenia',
carried out by the author under supervision of prof. Emil Erjavec at the
Chair for Agricultural Economics, Policy and Law at the Zootechnical
Department of the Biotechnical faculty.
