The Reserach On Relative Bio-value Of Nano-vitamin D₃ In Broiler

An experiment was conducted to evaluate the effects of ordinary vitamin D3(VD3) and nanoVD3 on growth performance, serum biochemical parameters, tibial quality and calcium and phosphorus metabolism rate of broiler from 1 to 42 days of age and to research the relative bio-value of nano VD3. This experiment can provide a theoretical basis for the use of nano VD3 in actual production.By using a single factor completely randomized design, seven hundred and ninety-two one-day-old AA broilers were randomly divided into 11 groups with 6 replicates in each group a 12 broilers in each replicate. Ordinary VD3 and nano VD3 were used to provide 0, 200, 400, 600, 800, 1000 IU/kg activity in a nutritionally completed corn-soybean meal diet. The experiment phase was divided into 1~21 d and 22~42 d.The results as follow:(1) At 1~21 d, 22~42 d and 1~42 d, the average daily weight gain(ADG), the daily feed intake(ADFI) of the treatment groups were significantly higher than those in control group(P<0.05), and the feed weight ratio(F/G) were significantly lower than the control group(P<0.05).with the increase of ordinary VD3 and nano VD3 level, ADG, ADFI and F/G had reached a plateau.(2) At 21 d, the total protein(TP) content of the treatment groups were significantly higher than the control group(P<0.05). The plasma calcium content of the fourth group was the highest. The calcium content of plasma 7~11 and the control group had no significant difference(P>0.05). The alkaline phosphatase(ALP) activity of the control group was the highest. At 42 d, the plasma calcium content of all groups were not significant(P>0.05), and the ALP of the control group was also the highest.(3) At 21 d, the tibia length, diameter, quality, tibia strength and tibia ash proportion of the control group were significantly lower than the treatment groups(P<0.05). At 42 d, the tibia length, diameter, quality of the control group were still lower than the treatment groups(P<0.05), and 1~6 groups were not significant difference in tibia strength(P>0.05). The tibia strength of the seventh group reached the maximum value.(4) At 21 d, with the increase level of VD3 and nano VD3, the calcium and phosphorus metabolism rate were increased gradually. At 42 d, the calcium and phosphorus metabolism rate of the tenth group had reached the maximum value. With the increase level of VD3 and nano VD3, the calcium and phosphorus metabolism rate were first increased and then decreased.Conclusion: No additional VD3 will directly lead to a decline in the growth performance of broilers. The tibia development was inhibited and the calcium, phosphorus metabolism rate were also affected. By using the exponential regression model, for 1~21 d, the ADG, ADFI, tibia weight, tibia strength, tibia ash ratio and calcium metabolism rate as the evaluation index, the relative bio-value(RBV) of nano VD3 were 1.76, 1.74, 0.84, 1.19, 1.13, 1.35 times respectively. For 22~42 d, the ADG, ADFI and calcium metabolism rate as the evaluation index, the RBV of nano VD3 were 1.36, 1.2, 1.37 times respectively.