Abstract
The current experiment was carried out to determine the effect of zinc (Zn) supplementation on digestibility of nutrients and blood minerals concentration during hot season of local growing lambs. In the current experiment, twenty-seven local growing Awassi lambs with live weight 25.92 kg± SD=4.29, and aged 8 months ±SD=1.1, were allocated randomly in single pens (1.50 x 1.30 m) by live weight in indoor hall to one of three experimental treatments during July (hot season). Zinc was added to drinking water in three different levels, 0 ml/day (0 mg Zn), 3 ml/ day (36 mg Zn) and 6 ml/day (72 mg) as treatments one (T1), two (T2) and three (T3) respectively. The animals were adapted to the experimental treatments for 3 weeks, followed by 5 days of feed and fecal samples collection for further laboratory proximate analysis to determine the digestibility coefficient of nutrients. At day three of sample collection, blood samples were collected by jugular venipuncture at 11 a.m. for blood minerals and biochemical determination. The results showed that Zn supplementation increased (P<0.001) blood serum Zn concentration. In addition, Zn supplementation decreased both blood serum albumin (P=0.001) and glucose (P=0.010) in T3, whereas serum ALP concentration increased (P=0.042) in T3. Zinc supplementation effectively improved nutrient digestibility coefficient, increased NDF (P=0.004) and ADF (P=0.020) digestibility, and tended to increase DM digestibility. The above results indicate that Zn supplementation may have a role in decreasing the negative effect of heat stress.
