| The effects of nicotinic acid and different levels of folic acid in diets on nutrients metabolism, immune function and performance of broilers researched in the thesis, and the physiological and biochemical mechanism was studied, too.7 treatments were set in this experiment, and each containing 3 repeats, each repeat was composed of 10 broilers. Treatmentâ… was control group, without folic acid and nicotinic acid. Treatmentâ…¡,â…¢,â…£supplemented folic acid 0.75mg/kg, 1.5mg/kg, 3.0mg/kg respectively, and treatmentâ…¤,â…¦,â…¥were supplemented nicotinic acid 60mg/kg and 0.75mg/kg, 1.5mg/kg, 3.0mg/kg respectively.Experiment one: At the 21-old day and 42-old day, record feed intake and average daily gain, calculate the the ratio of diet to meat. The results show that it could improve the day feed intake and the average daily gain, and reduce the ratio of diet to meat of broilers in diets supplied the different levels of folic acid significantly (P<0.05). It could very significantly improved the average daily gains of broilers by supplied the different levels of folic acid and 60mg/kg nicotinic acid (P<0.01). At the 42-old day, it could remarkably improve the average daily gain, day feed intake and the ratio of diet to meat of broilers by supplied different levels of folic acid and different levels of folic acid and 60mg/kg nicotinic acid(P<0.05). The treatmentâ…¢andâ…£have the best effect on gain, that is it could significantly improve the broilers gain by supplied1.5mg/Kg folic acid in diets (P<0.05).At the 42-old day, drew out two broilers in per repeat at random. The results show that it have not remarkable effect on the slaughter weight, slaughter rate, weight of all clean chamber,rate of all clean chamber and breast muscle rate in diets added the different levels of folic acid and the different levels of folic acid and 60mg/Kg nicotinic acid(P<0.05). It had remarkable effects on the abdomen fat weight and abdomen fat rate (P<0.05) or very significantly (P<0.01). It had remarkable effect on the breast muscle rate (P<0.05). It had remarkable effect on the leg muscle rate and weight (P<0.05).Experiment two: At 32 ~ 45-old day, randomly taking two broilers out from each repeat to do the metabolize experiment. The results showed that, it have significant effect on apparent digestibility rate of DM, CP, EE, CF, OM, and NFE (P<0.05).When the level of folic acid is 1.5~3.0mg/kg, the nutrients in diet have the most utilization. And nicotinic acid cooperated with folic acid promote broilers to utilize nutrient.At 21-old day and 42-old day, drew 2 broilers out per repeat to slaughter. We separated left breast muscle from body to analyze the composition of muscle. The results showed that, water, CP and EE in muscle haven't significant difference by supplying folic acid and nicotinic acid. But the contents of CP in muscle were increased along with improving folic acid level. Supplying nicotinic acid could induce the contents of EE in muscle, but difference was not significant (P>0.05).Experiment three: At 21-old day and 42-old day, drew 2 broilers out per repeat to collect blood. Separate serum to test serum biochemical parameter. The results showed that, when the folic acid level was 1.5-3.0mg/kg, the content of total protein and albumin in serum of 21-old broilers have significant... |
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