1-21日龄黄羽肉鸡烟酸需要量研究

Study on Niacin Requirement of Yellow-feather Broiler Chicks at 1 to 21 Days Age

采用单因子随机分组试验设计,选用1日龄快长型岭南黄羽肉公雏1 800只,分为6组,每组6个重复,每个重复50只鸡。处理1为空白对照组,处理2、3、4、5、6饲粮中烟酸添加水平分别为25、50、75、100、125 mg/kg,探讨1～21日龄黄羽肉鸡烟酸需要量。结果表明:与对照组相比,试验组21日龄体重、日增重显著提高,料重比降低(P<0.05)。添加烟酸对试验鸡胫骨重量、长度和折断强度影响均不显著(P>0.05)。与空白对照组相比,添加烟酸25 mg/kg可显著降低试验鸡血浆低密度脂蛋白固醇(LDL-C)水平(P<0.05),添加50 mg/kg时,可显著降低游离脂肪酸(NEFA)水平(P<0.05),当添加量超过125 mg/kg时,LDL-C和NEFA水平与对照组差异不显著(P>0.05),但总甘油三酯(TG)水平则明显升高,与各组差异显著(P<0.05)。以日增重为评价指标,依据双斜率拐点模型,1～21日龄黄羽肉鸡烟酸需要量为25mg/kg,低于NRC(1994)1～21日龄肉仔鸡烟酸推荐量35 mg/kg。

The experiment was conducted to determine the niacin requirement of yellow-feather broiler chicks before 22 days age. 1 800 one-day-age Lingnan yellow-feather male broiler chicks were randomly assigned to 6 dietary trearments. Each treatment consisted of 6 replicates with 50 birds per replicate. Five graded dose levels （25,50,75,100 and 125 mg/kg） of niacin were added into the basal diet. The results showed that niacin supplementation significantly improved body weight, average daily gain （ADG） and decreased feed：gain （F：G） of broiler chicks at 1 to 21 days age （P〈0.05） . There was no difference in weight,length and intensity of tibia among treatments （P〉0.05）. Niacin supplementation dose of 25 mg/kg and 50 mg/kg significantly lowered low density lipoprotein cholesterol and non-esterified fatty acid level in plasma compared with the control （P〈0.05）,when niacin supplementation was up to 125 mg/kg,it could significantly increase triglyeereide level （P〈0.05）. Based on ADG,the optimal niacin level estimated by double broken-line regression was 25 mg/kg,lower than NRC meat chick niacin recommended quantity.