饲料蛋白和脂肪水平对太湖鲂鲌冬片鱼种生长、体组成和消化酶活性的影响

DIETARY PROTEIN AND LIPID ON GROWTH PERFORMANCE, BODY COMPOSITION AND DIGESTIVE ENZYME ACTIVITIES OF WINTERLING CULTER ALBURNUS ♀×MEGALOBRAMA TERMINALIS

  • 摘要: 为优化太湖鲂鲌配合饲料配方, 设计3个饲料蛋白水平(36%、39%和42%)和3个脂肪水平(6%、8%和10%)的3×3因子实验, 配制9种实验饲料(P36L6、P36L8、P36L10、P39L6、P39L8、P39L10、P42L6、P42L8和P42L10), 分别饲喂9组3重复平均体重为8.59 g的太湖鲂鲌冬片鱼种60d, 以探讨饲料中不同含量的蛋白和脂肪对太湖鲂鲌冬片鱼种生长、饲料利用、体成分和肠道消化酶等的影响。结果表明: 实验鱼摄食蛋白水平为39%和42%的6种饲料(P39L6、P39L8、P39L10、P42L6、P42L8和P42L10) 后, 其鱼体增重率和饲料系数在组间无显著差异(P>0.05), 但鱼体增重率均比摄饲料蛋白水平为36%的3种饲料(P36L6、P36L8和P36L10)的实验组要高(P<0.05), 而饲料系数则较低; 在同一饲料蛋白水平时, 饲料脂肪水平变化对蛋白质沉积率无显著影响; 摄食蛋白质水平为39%饲料的3个实验组的蛋白质沉积率均高于饲料蛋白为36%的3个实验组。饲料同一脂肪水平时, 饲料蛋白水平从39%提高到42%对蛋白质沉积率有降低的趋势, 但差异不显著; 脏体指数(VSI)与饲料脂肪水平(L)呈正相关(VSI=0.223L+4.611, R=0.746, P=0.000); 全鱼粗脂肪随饲料蛋白的升高而降低, 但随饲料脂肪水平的升高而增加; 摄食3种低脂肪水平(6%)的饲料(P36L6、P39L6和P42L6)的太湖鲂鲌肌肉粗脂肪含量均显著低于摄食其他6种脂肪水平较高(8%和10%)饲料组; 摄食3种蛋白水平为36%的饲料(P36L6、P36L8和P36L10)后, 太湖鲂鲌肠道淀粉酶活性显著高于蛋白水平39%和42%的饲料组; 太湖鲂鲌肠道蛋白酶和脂肪酶活性均不受饲料蛋白和脂肪水平及其交互作用的影响; 因此, 能使实验鱼获得良好生长和饲料利用的适宜饲料蛋白和脂肪水平分别为39%和6%。过低的饲料蛋白水平和过高的饲料脂肪水平易导致鱼体脂肪积累过多。

     

    Abstract: To optimize the feed formulation of a hybrid fish, Culter alburnus ♀ × Megalobrama terminalis ♂, a 3×3 factorial feeding trial was conducted. Nine diets were prepared with varying protein levels (36%, 39% and 42%) and lipid levels (6%, 8% and 10%) to evaluate production responses, including growth, feed utilization, body composition, and activity of digestive enzymes. The diets, labeled as P36L6, P36L8, P36L10, P39L6, P39L8, P39L10, P42L6, P42L8, and P42L10, were fed to 9 triplicate groups of fish with an initial average body weight of 8.59 g for 60d. Weight gain rates (WGR) and feed conversion ratios (FCR) of fish fed diets with protein levels of 39% and 42% (P39L6, P39L8, P39L10, P42L6, P42L8, and P42L10) did not show significantly differences among treatments (P>0.05). However, fish fed diets with a protein level of 36% (P36L6, P36L8, and P36L10) exhibited lower WGR and higher FCR (P<0.05). Protein retention (PR) of fish fed diets with one level of dietary protein were not significantly different, but fish fed diets with a dietary protein level of 39% (P39L6, P39L8, and P39L10) had higher PR compared to those of fish fed diets with 36% dietary protein (P36L6, P36L8, and P36L10). PR were not significantly different between treatments of fish fed diets with one level of dietary lipid and dietary protein level of either 39% or 42%; Viscera-somatic index (VSI) positively correlated with dietary lipid level (L) (VSI=0.223L+4.611, R=0.746, P=0.000). Whole fish body lipid tended to decrease with increasing dietary protein level and increase with increasing dietary lipid level. Fish fed diets with a dietary lipid level of 6% (P36L6, P39L6, and P42L6) had lower muscle lipid compared to those fed diets with 8% and 10% dietary lipid levels. Fish fed diets with a protein level of 36% (P36L6, P36L8, and P36L10) exhibited higher intestinal amylase activities compared to those fed diets with higher dietary protein levels. Intestinal protease and lipase activities were not significantly influenced by dietary protein level, lipid level or their interaction. Based on these results, it can be concluded that a dietary protein level of 39% and a dietary lipid level of 6% are suitable for maintaining good growth performance and feed utilization in the trial fish. Low dietary protein and high dietary lipid may lead to additional body lipid deposition.

     

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