عنوان مقاله [English]
Introduction:A The use of vitamin C in conditions of heat stress and poultry rejuvenation compared to this stressor has been recorded by researchers for many years (Nameghi 1386). .
The experiment was a completely randomized design with 7 treatments and 4 replications, 10 birds each. Treatments included: control diet, 3 level of vitamin C (0, 100 and 200 mg/kg) and 3 level of Nano vitamin C (0, 100 and 200 mg/kg). The experimental diets were based on corn and soybean. During the experiment, water and food were offered ad libitum. Body weight and feed intake at the end of each period were measured and used to calculate body weight gain and feed conversion ratio. At d 42 one bird from each replicate was selected and killed to measure the internal organ weights. Also, the weight and length of the jejunum were calculated, and partly for intestinal morphology in formalin 10%.
Results and discussion: The effect of dietary treatments on feed consumption in broiler chickens was significant (P<0.05). Chickens that received 200 mg of vitamin C kg-1 diet had the greatest feed intake than other chicks. The results of this study was in line with the results of Kutlu and Forbes (1993) who reported that 250 mgof vitamin C increased these parameters. Experimental treatments had a significant effect on the weight gain of chicks (P<0.001). Chickens that received 50 mg nano vitamin C had the greatest weight gain compared to other treatments. According to these results, Roshani et al. (2006) reported that vitamin C during the stress period improved the feed intake and daily weight gain. Sahin and Kucuk (2002) reported that the use of 200 mg vitamin C /kg of diet improved the feed intake of quails under stress conditions. Gross (1988) showed that vitamin C under stress conditions caused an increase in daily weight gain in broiler chicks. In another study, Ping et al. (2011) showed that nano multivitamin improved weight gain, feed intake and reduced mortality. Chicks fed 50 mg nano vitamin C had the best conversion ratio compared to other treatments. The results of this experiment are consistent with the results of Alba et al. (1393), Kutlu and Forbes (1993), and Amakye et al. (2000). They reported that the use of vitamin C supplementation significantly reduced the feed conversion ratio compared to the control group. Sahin and Kucuk (2002) reported that using 200 mg/kg of vitamin C improved feed consumption and feed conversion ratio under heat stress. Researchers reported that vitamin C supplementation in summer did not have a significant effect on the relative weight of the thigh, which is similar to the results of this experiment (Konca, 2009). Relative weight of breast and carcass was affected by experimental treatments and a significant difference was observed between the groups. The greatest relative weight of the carcass was related to birds received 200 mg vitamin C kg-1 diet. The greatest relative weight was related to treatment with 50 mg nano vitamin C. According to these results, Sahin et al. (2002) reported that vitamin C supplementation of 250 mg/kg of diet improved live weight, nutritional efficiency and carcass traits. Also, Roshani et al. (2006) reported that vitamin C supplementation during the stressful period significantly increased the weight of the chest. Rafie et al. (1393) reported that 250 mg/kg vitamin C increased breast weight and could somewhat reduce the negative effects of heat stress. Darmankouhi (2005) reported that ascorbic acid increased the carcass quality and yield under heat stress conditions. Relative weight of liver was not affected by experimental treatments. The effect of treatments on relative weight of spleen was significant (P<0.05). Chickens fed 100 mg of vitamin C had the greatest relative spleen weight. An experiment showed that vitamin C had no significant effect on different gastrointestinal system (Konca, 2009). Nemati et al. (1392) reported that the use of antioxidants such as vitamin C under stress conditions, reduced spleen relative weight, immune system, and mortality. Raeisi et al. (1394) showed that the effect of different levels of vitamin C on the relative weight of the spleen and liver was significant. The greatest amount of relative length of jejunum was belonged to birds received 100 mg of nano vitamin C. This level was significantly different from that of the control group and 50 mg vitamin C (P<0.05). The relative weight of the jejunum was not affected by the treatments. Treatments did not have a significant effect on white blood cells. The greatest amount of RBC was related to treatment with 200 mg nano vitamin C (P<0.05). This treatment was significantly different from control treatments, 50 mg vitamin C, 50 mg nano-vitamin C and 100 mg vitamin C (P<0.001). The greatest amount of hemoglobin was related to the level of 200 mg nano vitamin C (P<0.001). The experimental treatments did not have any effect on the heterophile levels. The greatest amount of lymphocyte was related to birds fed 50 mg and 100 mg nano vitamin C(P<0.001), which had a significant difference with 200 mg vitamin C and nano vitamin C (P<0.05). Gross (1988) showed that the number of lymphocytes was increased by the use of vitamin C in broiler diets. Taghilu et al. (1389) showed that 0.05% of vitamin C improved hematocrit. Regarding the effect of vitamin C, Tuleun et al. (2011) showed that vitamin C had no significant effect on blood cell parameters. In another study Mirzapoor et al. (1394) examined levels of 250 and 500 mg of vitamin C on blood parameters. Results showed that vitamin C increased the amount of red blood cells and hemoglobin and improved hematocrit of the blood.The greatest amount of glutathione peroxidase enzyme was related to the level of 200 mg nano vitamin C kg-1 diet(P<0.001), which was significantly different from other treatments. Research has shown that vitamin C has an electron capability that acts as a regenerator of active oxygen species (ROS) and has a moderating role in the antioxidant defense activity (Sies et al. 1995). Chickens that received different levels of vitamin C and nano vitamin C had a significant difference compared to the control group (Data was not shown in this article).. Rafiei et al. (1393) showed that lemon powder with 250 mg/kg of vitamin C reduces the negative effects of heat stress and improves the immune response of the bird. Pardu et al. (1985) reported that the consumption of 1000 mg/kg of vitamin C would increase antibody production against SRBC. Mccorre et al. (1980) showed that ascorbic acid can increase the activity of B lymphocytes improving humoral immune responses. Amakye et al., reported vitamin C improve humoral immune response in broiler chicks. Conclusion: The results of this experiment showed that consumption of 50 mg nano vitamin C kg-1 diet had a positive effect on growth performance of broiler chicks, thus improving the weight gain and feed conversion ratio. Also increased the weight of the liver, spleen and bursa, and improved immune function and the rate of humoral immune response. Also, 200 milligrams of nano-vitamin C kg-1 diet increased the concentration of hemoglobin and glutathione peroxidase enzyme under heat stress conditions.