饲料能量和维生素B_6对乌鳢生长和蛋白质合成与调控的影响

Effects of dietary energy and vitamin B_6 on growth and protein synthesis of Channa argus

本研究旨在探讨饲料能量和维生素B6分别与蛋白质的交互作用对乌鳢生长和蛋白质合成与调控的影响。选择健康的体重为(10.92±0.42)g的乌鳢(Channa argus)在池塘网箱中进行两个试验。试验一:采用3×3双因子试验,设计了3种不同蛋白质水平[34.7%、38.3%和41.8%可消化蛋白(DP)]和3个能量水平[14.5、16.0 MJ和17.5MJ的可消化能(DE)]的9种试验饲料;试验二:采用3×3双因子试验,设计了3个可消化蛋白水平(34.5%、38.5%和42.0%)和3个维生素B6水平(6、18 mg/kg和30 mg/kg)的9种试验饲料,饲养8周,研究对其特定生长率、核酸和血中IGF-Ⅰ的影响。试验一:在相同饲料DE水平下,鱼体增重随DP水平升高而升高;在相同饲料DP水平下,鱼体增重先随饲料DE水平升高而升高,而后随DE水平升高而降低。饲料蛋白质水平极显著地影响乌鳢的RNA/DNA比率(P<0.01),显著影响RNA含量及血液中IGF-Ⅰ的含量(P<0.05)。能量水平极显著地影响乌鳢的RNA/DNA比率及RNA含量(P<0.01),显著的影响血液中IGF-Ⅰ的含量(P<0.05)。乌鳢生长和RNA/DNA及其血中IGF-I呈正相关(P<0.05)。试验二:随着蛋白质水平的增加,乌鳢的特定生长率和平均增重率呈先升高后稳定的趋势;随着维生素B6的添加,乌鳢的生长显著增加(P<0.05)。饲料蛋白质水平极显著地影响乌鳢的RNA/DNA比率、RNA含量及血液中IGF-Ⅰ的含量(P<0.01),随着蛋白质水平的增加,乌鳢的RNA/DNA比率及RNA含量呈先升高后稳定的趋势。维生素B6极显著地影响乌鳢的RNA/DNA比率及RNA含量(P<0.01),与乌鳢生长和RNA/DNA及其血中IGF-Ⅰ呈正相关(P<0.05)。在本试验条件下,适宜蛋能比(23.3 g/MJ)、蛋白质(34.5%～42.0%)和维生素B6(18～30 mg/kg)的添加量,通过提高血中IGF-I的含量和促进蛋白质的合成来促进乌鳢的生长。

Effects of interaction of energy and vitamin B6 respective on protein on growth and protein synthesis and regulation were investigated in this study.In the trail 1, Channa argus was fed diets that contained three digestible protein （DP） （34.7 % ,38.3 % ,41.8 %） and three digestible energy （DE） levels （14.5,16.0,17.5 MJ/kg）,In the trail 2,Chcuma argus was fed diets that contained three DP（34.5 % ,38.5 % ,42.0 %） and three vitamin B6 levels （6,18,30 mg/kg）,The two trails with respective 3 x3 faetoral design were investigated to study the effects of energy and vitamin B6 on weight gain, RNA and IGF-I of snakehead Channa argus[initial body weight （10.92 ± 0.42）g]in cage for 8 weeks.Results of trail 1 indicated that weight gain of the fish increased with the increase of dietary protein level at same dietary energy level, weight gain of the fish increased with the increase of energy from 14.5 MJ/kg to 16.0 MJ/kg DE ,and then declined with the continuous increase of energy level up to 17.5 MJ/kg DE at same dietary protein level.Dietary protien significantly in- fluenced RNA/DNA ratio（P 〈 0.01 ）,energy level significantly influenced RNA/DNA ratio RNA（P 〈 0.01 ） and significant- ly influenced insulin-like growth factor -I （IGF-I）levels （P 〈 0.05）.IGF-I and RNA/DNA showed a positive correlation with growth （P 〈 0.05 ）.Results of trail 2 indicated that dietary protein level significantly influenced weight gain of snake- head （P 〈 O.05）.Growth performance had significantly improved with vitamin B6 supplementation （P 〈 0.05） ,however in- teraction of protein level and vitamin B6 showed no significant effects on growth performance of snakehead （P 〈 0.05 ）.Di- etary vitamin B6 level significantly influenced RNA/DNA ratio,RNA and IGF-I content （P 〈 0.01 ）.IGF-I and RNA/DNA showed a positive correlation with growth （P 〈 0.05）.In conclusion,the optimal protein to energy ratio was 23.3 g/MJ and feeds with adequate vitamin B6 supplementation（ 18 - 30 mg/kg） in proper protein level （34.5 % - 42.0 %） could improve growth performance and protein metabolism for Channa argus.