Effect of drinking saline water and feed shortage on adaptive responses of sheep and camels

This study investigated the effect of saline load and inadequate feed intake on some of the adaptive physiological responses in female sheep and camels, raised under semi-arid conditions. The experiment comprised five consecutive periods, P1-P5, of 40 days each, during which levels of both energy and protein were gradually decreased by increasing the roughage portion in the diet. Sheep and camels were divided into three groups according to the type of drinking water; namely a fresh water (F) group (280 parts per million total dissolved salts; ppm TDS), low saline (LS) group (7650 ppm TDS) and high saline (HS) group (13,535 ppm TDS). Saline water was obtained by diluting seawater with tap water. In sheep, live body weights (BWs) decreased significantly (p < 0.01) with decreasing nutrient intake, with average final loss equal to 8.4%. Plasma glucose decreased with decreasing protein intake, but as energy intake increased the effect of protein shortage disappeared. Also plasma glucose levels in sheep decreased from a level of 3.51 mmol/l in the F group to 2.89 mmol/l in the HS group. Concentrations of liver enzymes aspartate aminotransaminase (AST) and alanine aminotransaminase (ALT) in sheep increased in plasma in relation to saline load especially at low nutritional level. The activity of the acetylcholine esterase enzyme (AChE) in its three sites; blood, red blood cells and plasma was depressed significantly by both saline load and decreased feed intake. At the P2 period, salinity depressed acetylcholine in its three sites to 60-67% in the HS group as compared to the control. The depression during the P5 period reached 41-54%. Extracellular fluids (ECFs), interstitial fluids (ISF), plasma volume (PV) and blood volume (BV) in the ewes decreased (p < 0.05) by increasing salinity concentration. Decreasing feed intake lowered ECF, ISF and BV from the P2 period. In camels, live BWs decreased insignificantly by decreasing feed intake with a final BW loss of 1.9%. Plasma glucose was not affected by salinity. Protein deficiencies had no effect on plasma AST of camels, but both salinity and low level of nutrient intake affected the concentration of enzyme ALT. Nutrient shortages and saline load affected activity of AChE at the P4 and P5 periods. The inhibition of the enzyme activity during P5 due to high salinity treatment reached 91% in blood, 63% in RBCs and 50% in plasma as compared to the control group. Body fluid compartments of camels were not affected by salinity, only by reduced feed intake. The results indicated better tolerance of camels than sheep to both saline load and feed shortage. (C) 2002 Published by Elsevier Science B.V.