EFFECT OF COPPER AND CADMIUM CONTAMINATED DIETS ON WATER INTAKE, RUMINAL ENZYME ACTIVITIES, CHARACTERISTICS AND NUTRIENT DIGESTIBILITY IN SHEEP

Nine healthy non-pregnant Rahmani, ewes were used in this study to
evaluate the effect of copper and cadmium chloride as heavy metals on water intake,
ruminal enzymes and nutrient digestibility. The animals were divided into three
groups. The first group was fed 400-g concentrate mixture and 20 g DMlI<g LW of hay
and used as a control group. Whereas the second and third groups were fed the same
diet but the concentrate was treated with CuCI2 and CdCb, respectively daily just
before feeding, CuCI2 or CdCI2 solution (5-mmollL) was sprayed on the weighed .
amount of concentrate (400 glh/d). Diets were fed once daily. Drinking water
significantly (P? 0.05) increased in the ewes received copper or cadmium
contaminated diet. Copper and cadmium decreased significantly (P?0.01) urease
activity, whereas no significant differences were observed in the case of alanine
aminotransferase (AL T), aspartate aminotransfarase (AST) , and gamma-glutamyl
transferase (GGT) activities. The activity of all ruminal enzymes studied was
significantly affected by cadmium treatment; both AL T and AST activities were
significantly increased (P?0.01) while the GGT activities were significantly decreased
(P?0.05).Ruminal ammonia concentration was significantly decreased (P?0.05) by
copper or cadmium chloride treatment. Lower values were obtained in the copper
treated diet animals, but without significant difference (P?0.05) with cadmium treated
diet. Ruminal pH and total VFA concentrations were unaffected (P?0.05) by treating
the diets with both heavy metals. Copper or cadmium treated diets had decreased
significantly (P?O.05) branched-chain VFAs (isobutyric and isovaleric acids), acetic
and butyric acids concentrations and had no significant effect on propionic and valerie
acids. Treating diets with heavy metals (copper or cadmium) resulted in reduction in
the digestibility coefficients of all nutrient components except nitrogen free extract.
Results of the present study indicating that, in sheep, eating diets contaminated with
copper or cadmium (5-mmol) could increase water consumption, negatively affect
several ruminal enzymes activity and nutrient fermentation.