复方精油在肉兔日粮中适宜添加量的研究

Study on the suitable amount of compound essential oil in rabbit diet

本试验旨在探究肉兔日粮中添加不同水平的复方精油(CEO)对肉兔生产性能、屠宰性能、血清免疫、抗氧化性能和兔肉品质的影响,以确定复方精油在肉兔日粮的适宜添加量。试验选取240只(公母各半)35日龄断奶、体重相近的健康新西兰兔,随机分为5个处理组,每组16个重复,每个重复3只兔子。对照组:基础日粮,CEO 150组:基础日粮+150 mg/kg CEO,CEO 300组:基础日粮+300 mg/kg CEO,CEO 450组:基础日粮+450 mg/kg CEO,CEO 600组:基础日粮+600 mg/kg CEO。预饲期5 d,试验期为56 d。试验结果表明:(1)复方精油组全期平均日增重与对照组相比差异不显著(P> 0.05);精油组比对照组显著提高了1~14、15~28、43~56 d以及试验全期的采食量(P <0.05);精油组与对照组相比全期料重比有降低的趋势(P=0.06)。(2)试验组胴体重与对照组相比有降低的趋势(P <0.1),随精油添加水平的增加,呈二次曲线变化趋势(P=0.06);但添加复方精油对全净堂率和半净堂率影响不显著(P> 0.05)。(3)复方精油显著降低了试验组的蒸煮损失率(P <0.05),与对照组相比试验组平均降低了6.71%,且有符合二次曲线的趋势(P=0.07);试验组较对照组肉色的红度显著提高(P <0.01),且符合线性趋势(P <0.01)。(4)添加不同浓度的复合精油显著提高了肉兔血液中IgG的含量(P <0.05),且当添加量为300 mg/kg时血液中Ig G的含量最高;试验组肉兔血清中丙二醛(MDA)的含量显著降低(P=0.03),抗氧化能力提高。综上所述,日粮中添加0~600 mg/kg的复方精油,可以改善肉兔的生产性能、肉品质、免疫力、抗氧化能力,其中胴体重、蒸煮损失率与肉色a*呈现出二次曲线的剂量效应,胴体重、蒸煮损失率随添加量的增加,效应增强,但复方精油添加量过高,则表现出负面效应。本试验条件下,适宜添加量为300 mg/kg。

The purpose of this experiment was to investigate the effect of adding different levels compound essential oil(CEO) on production performance,slaughtering performance,serum immunity,antioxidation of meat rabbit and meat quality,and determining the appropriate amount of compound essential oil in the diet of meat rabbits.A total of 240 New Zealand meat rabbits(half male and half female) at the same weaned age of 35 days were selected and randomly divided into 5 groups,each group had 16 replicates with 3 rabbits per replicate. Control group:basic diet,CEO150 group:basic diet +150 mg/kg CEO;CEO 300group:basic diet+300 mg/kg CEO;CEO 450 group:basic diet +450 mg/kg CEO;CEO 600 group:basic diet+600 mg/kg CEO;The pre-feeding period was 5 days,the formal experimental period lasted for 56 days.The results showed as follow:(1) It was no significant difference in the average daily gain between the compound essential oil group and the control group(P > 0.05);Different concentration compound essential oil could significantly improve 1 ~ 14,15 ~ 28,1 ~ 56 d feed intake of meat rabbit(P < 0.05);Compared with the control group,the feed to gain ratio of the essential oil group tended to decrease during the whole test(P =0.06).(2) Compound essential oil had a tendency to improve the carcass weight of meat rabbits(P < 0.1). The test group and control group confirmed second-degree curve in carcass weight(P < 0.05,P =0.06);However the addition of compound essential oil had no significant effect on the whole net carcass rate and half net carcass rate(P > 0.05).(3) The compound essential oil could significantly reduced the cooking loss rate(P <0.05),compared with the control group,the average decrease of the test group was decreased by 6.71%,and there was a tendency to conform to the quadratic curve(P =0.07);The redness of flesh color in the test group was significantly improved(P < 0.01),and accorded with the linear trend(P < 0.01);(4) Diet supplemented different concentrations of compound essential oil could significantly increased the content of IgG in the blood of meat rabbits(P < 0.05),and the content of IgG in the blood was the highest when the addition amount was300 mg/kg. The content of MDA in the serum of meat rabbit in the test group was significantly reduced(P =0.03),and the ability of antioxidation was improved. To sum up,diet supplemented 0 ~ 600 mg/kg compound essential oil could improve the production performance,meat quality,immunity and antioxidant capacity of meat rabbits,among them carcass weight,cooking loss rate and meat color a*showed second-degree curve effect,with the increase of carcass weight and cooking loss rate,the effect was enhanced. However,if the compound essential oil was added too high,it will show negative effects.Under the test conditions,the suitable addition amount was 300 mg/kg.