This study was carried out on 90 broiler chicks which divided into three groups. The first group has been given 0.75 g/L potassium nitrate and the second group was given 1 g/L potassium nitrate with drinking water for 30 days, While the third group w
as regarded as a control.
The birds were reared in same keeping house and feeded with the same ration without any additives and no vaccinations were applied.
All birds were sacrificed and examined by naked eye. Then the thymus gland was fixed by formalin and stained microscopic sections were examined by microscope.
The histological changes in the birds which dosed by 1 g/L and 0.75 g/L of nitrate were similar and the observed changes were the small size of cortex in some lobules, and the cortex were separated from bulb with increase the number of Hassall bodies in the bulb region, also there were vacuoles and reticular cells in different stages of degeneration and edema in the connective tissues in comparison with control group.
These results confirmed that nitrate had toxic effects on the tissues of thymus, and as a sequence reduced the number of T cells which lead to decrease the resistance and Immune response of the birds and retarded the growth rate.
In this study, five barley cultivars (Arabi Abiad, improved Arabi Abiad,
Arabi Aswad, Furat 1, Furat 2) from the harvest of 1999 season were used .The
chemical composition, Amino acid content, B-Glucan content, viscosity, cell
wall compounds, and
metabolic energy were determined in two laboratories in
Germany .A metabolism trial was also conducted to study the nitrogen balance,
dry matter, Organic matter, ash, and some other productivity parameters.
Results showed that the influence of barley varieties on chemical composition of
the grains was clearly visible. The crude protein content ranged from 138 for
Furat 1 to 169 gr/Kg dry matter for Arabi Abiad. The difference in starch
content resulted in differences in metabolic energy Values from 12.4 for Furat 1
to 13.3 MJ/Kg dry matter for Arabi Aswad. The food assimilation trial showed
that the varieties Arabi Aswad gave the best productivity parameters, and the
crude protein content did not adversely affect the nitrogen balance in all the
barley varieties meald, but it was the lowest for the Arabi Aswad variety meal
(p <0.05). There were no significant differences in dry matter and organic
matter digestibility for diets containing Arabi Abiad, Furat 1 and Furat 2.
