عنوان مقاله [English]
Introduction Feed constitutes 70 to 75 percent of poultry flock costs which vitamins constitute 0.08 % of diet and 2 % of feed costs. Vitamins as a group of complex organic compounds are needed in small amounts for normal metabolism of the body. Researches have shown that vitamins with smaller particles as vitamin supplements, were more effective and showed higher bioavailability. Nano form of supplementation increases the surface area which possibly could increase absorption and thereby utilization of vitamins leading to reduction in the quantity of supplements and through higher bioavailability. Their greater bioavailability shows that nano-particulate vitamin compositions can be given in smaller doses with less amount of that vitamins passing through the body unabsorbed. Most vitamins and other substances that are insoluble in water when formulated as nanoparticles, can be easily solved in water and even can penetrate to the body parts that are impervious to the macro particles. this study was conducted to compare the efficacy of Nano-multivitamin (NMV) with common vitamins premix (CVP) on performance, some blood parameters and immune responses of broiler chickens to verify the beneficial effects of nano-vitamins in poultry nutrition,.
Materials and Methods The experiment was conducted in a completely randomized design for 45 days. A total of 600, 1-d-old male broiler chicks (Ross strain) were randomly assigned to 10 treatments with 5 replicates and 12 chicks each. Mash basal diets were prepared and balanced for energy and all nutrient except vitamins according to the Ross Nutrition manual (2007), for starter (1-10 d), grower (11-24 d) and finisher (25-45 d) periods. Liquid NMV and Powder pure vitamins were added to diets after dilution with wheat bran to achieve weight of 2.5 kg of each premix for each ton of feed (2.5 kg premix/ton diet = 100% of recommended level). The size of NMV particles were 20-400 (nm) and the manufacturer's recommendations were used in feed or drinking water. In order to unify the experimental diets, 8 gr of vitamin C was added to Ross recommended vitamin premix and also 400 gr choline chloride (60%) was added to each 2.5 kg of three vitamin premix. Treatments 1, 2 and 3 respectively consisted basal diet (BD) + 50%, 100% and 150% NMV manufacturer recommended levels; treatments 4, 5 and 6 respectively consisted BD + CVP with vitamins levels equal to treatments 1, 2 and 3; treatments 7, 8 and 9 respectively consisted BD + 50%, 100% and 150% CVP which satisfied the Ross strain vitamins recommended levels; and treatment 10 consisted BD without vitamins premix supplementation, as a negative control. Feed intake, weight gain and feed conversion ratio were measured for each pen at 10, 24 and 45 days of age and feeding the diets were removed 5 hours before slaughter. SRBC (SRBC 1%) and CBH (PHA-P) tests were used to assess the humoral and cellular immunities of two chicks of each replicate, respectively. At the age of 42 days, one bird from each pen was selected and blood samples were collected from the wing vein. At the age of 45, one bird from each pen was selected and slaughtered to determine the carcass characteristics.
Results and Discussion Results showed that, treatments 2 and 3 significantly increased average body weight and daily weight gain of the birds in starter period (1-10 d) in comparison with other groups. Treatment 10, significantly decreased feed intake and daily weight gain and increased feed conversion ratio in all periods. This improvement might be due to the higher bioavailability of Nano-vitamins because of particles size reduction or converting fat-soluble vitamins to water-soluble vitamins. Omara et al (2009) demonstrated that nanotechnology can increase the bioavailability of fat-soluble compounds and increase their bioavailability. SRBC test showed no significant differences among the treatments. CBH test revealed that the birds receiving treatment 10 had significantly lower cellular immune response, 24 hours after injection, in comparison with other treatments. Treatment 10 significantly reduced triglyceride levels of serum and breast yield and significantly increased the relative weight of wings in carcasses and relative length of small intestine in comparison with other treatments.
Conclusion The results of this study showed that using NMV in the diet of broiler chickens may improve growth performance of broiler chickens just in the starter period.