2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P04 NITROGEN IN bREEDING LAyING hENS AND
ENVIRONMENT PROTECTION
MáRIA AnGELOVIČOVá, MAREK AnGELOVIČ and
MIROSLAVA KAČánIOVá
Faculty of Biotechnology and Food Sciences, Slovak University
of Agriculture, Tr. A.Hlinku 2, Nitra, 949 76 Slovakia,
maria.angelovicova@uniag.sk
Introduction
At EU–15 level the gross nitrogen balance in 2000
was calculated to be 55 kg ha –1 , which is 16 % lower than
the balance estimate in 1990, which was 66 kg ha –1 . In 2000
the gross nitrogen balance ranged from 37 kg ha –1 (Italy)
to 226 kg ha –1 (the netherlands). All national gross nitrogen
balances show a decline in estimates of the gross nitrogen
balance (kg ha –1 ) between 1990 and 2000, apart from
Ireland (22% increase) and Spain (47% increase). The following
Member States showed organic fertilizer application
rates greater than the threshold of 170 kg ha –1 specified by
the nitrates Directive in 2000: the netherlands (206 kg ha –1 )
and Belgium (204 kg ha –1 ). The general decline in nitrogen
balance surpluses is due to a small decrease in nitrogen input
rates (–1.0 %) and a significant increase in nitrogen output
rates (10 %). The gross nutrient balance for nitrogen provides
an indication of potential water pollution and identifies
those agricultural areas and systems with very high nitrogen
loadings. As the indicator integrates the most important agricultural
parameters with regard to potential nitrogen surplus
it is currently the best available approximation of agricultural
pressures on water quality. High nutrient balances exert pressures
on the environment in terms of an increased risk of leaching
of nitrates to groundwater. The application of mineral
and organic fertilizers can also lead to emissions to the atmosphere
in the form of nitrous dioxide and ammonia, respectively.
Gross nitrogen balances are above 100 kg per ha in the
netherlands, Belgium, Luxembourg and Germany. They are
particularly low in most Mediterranean countries given the
overall lower livestock production in this part of Europe.
It is currently not possible to provide gross nitrogen balance
estimates for the new EU Member States and the accession
as the relevant statistical data are under elaboration. national
balances, however, can mask important regional differences
in the gross nutrient balance that determine actual nitrogen
leaching risk at regional or local level. Individual Member
States can thus have acceptable gross nitrogen balances at
national level but still experience significant nitrogen leaching
in certain regions, for example in areas with high livestock
concentrations. There are a number of regions where pig
livestock units have increased by more than 25 % between
1990 and 2000 (for example, north-western Denmark, northwestern
France, north-eastern Spain and northern Belgium).
These are likely to be regional ‘hotspots’ for high gross nitrogen
balances that can lead to environmental pressures. Member
States with high nitrogen balances are making efforts
to reduce these pressures on the environment. These build
s341
on a range of different policy instruments, requiring considerable
political effort to succeed given the significant social
and economic consequences of reducing livestock production
in many affected areas 3,4 .
Experimental
We realized experiments with laying hens Shaver
Starcross 288, which ingested feed mixture with different
protein content. In six experiments laying hens fed feed
mixture with protein contents 173.10 g per kilogram and in
four experiments were used feed mixture with protein contents
146.12 or 146.68 g per kilogram. It is soya cereal type
assigned for laying hens. The laying hens ingested fodder ad
libitum.
Within experiments were researched:
protein contents in feed mixture in one kilogram (chemical
analysis – Kjeldahl method and calculation),
excreted nitrogen [g kg –1 •
•
] in dropping per bird and day
(chemical analysis – Kjeldahl method and calculation).
Results
Higher protein contents 173.10 g per kilogram of feed
mixture resulted in excreted dropping at laying hens higher
nitrogen contents in compare with protein contents 146.40 g
per kilogram feed mixture. After ingestion of feed mixture
with protein content 173.10 g per kilogram was nitrogen
content in dropping from 1.88 g per bird and day. The laying
hens, which fed feed mixture with protein contents 146.40 g
per kilogram, excreted the nitrogen in dropping 1.38 g per
bird and day. From these results follows that near decrease
protein contents in feed mixture from 173.10 to 146.40 g
per kilogram is possibility of nitrogen decrease in excreted
dropping at laying hens about 26.60 % per bird and day. This
different of decrease of excreted nitrogen in dropping at layers
is statistically significant (P < 0.001). Correlation coefficient
between content of crude protein in feed mixture and content
of nitrogen in dropping at layers has high level r = 0.99.
Low-protein diet system for layers with addition of
amino acids is beside biologically-cattle-breeding, economical
and ecological too.
Progressive decrease of proteins content to 146.0 g per
1 kg feeding mixture set up the order of limiting amino acids
for layers: methionine, lysine, tryptophane and threonine 5 .
On bases of results model trials on layers were concluded
that feeding, fat-enriched mixture supplied DL-methionine,
choline chloride and vitamin B 2 by need of the effective
Table I
Excreted nitrogen [g kg –1 ] in dropping at laying hens, which
ingestion of feed mixture with different protein contents
Trial Index SD v % t-test
1 st CP [g kg –1 ] 173.10 0.91 0.52 55.68 +++
2 nd CP [g kg –1 ] 146.40 0.32 2.68
1 st n [bird day –1 ] 1.88 0.005 0.22 18.52 +++
2 nd n[bird day –1 ] 1.38 0.02 1.57