饲料中添加适宜水平铁对建鲤肉质、鱼糜稳定性及组织蛋白酶B/L的影响

Effect of Suitable Dietary Iron Supplement on the Fillet Quality,Surimi Stability and Cathepsin B/L of Jian Carp (Cyprlnus carpio var Jian)

探讨饲料中添加适量铁对建鲤肉质、鱼糜品质及其肌肉中组织蛋白酶B/L的影响。以添加适宜水平铁的饲料饲喂90 d的建鲤(适宜组,铁实测质量分数146.1 mg/kg)为研究对象,同时以未添加铁组(缺乏组,铁实测质量分数53.9 mg/kg)作为对照。采样后测定鱼肉品质指标及肌肉中组织蛋白酶B/L活性,并采用免疫组化法进行蛋白表达定量;而后将2组鱼肉加工为鱼糜,并测定其稳定性指标。结果表明,与缺乏组相比,适宜组肌原纤维耐折力、断裂指数分别稍有上升及下降,但差异不显著(P>0.05);剪切力极显著增加31.80%(P<0.01),可溶胶原蛋白含量、不溶胶原蛋白含量和总胶原蛋白含量均分别极显著增加305.45%、180.98%、219.35%(P<0.01)。适宜组鱼肉p H及失水率略呈下降趋势,差异无统计学意义(P>0.05)。适宜组组织蛋白酶B/L活性分别极显著(P<0.01)及显著(0.01<P<0.05)低于缺乏组,免疫组化显示两种酶在建鲤肌肉中均有表达,且适宜组表达量均极显著低于缺乏组(P<0.01)。适宜水平铁能极显著提高鱼糜肌动球蛋白初始Ca^2+-ATPase活性、总疏基含量(P<0.01),降低二硫键含量(0.01<P<0.05)、表面疏水性(P<0.01)及TBA值(P<0.01)。饲料中添加适宜水平铁下调了建鲤肌肉CAT B/L的活性及表达量,改善了建鲤鱼肉的硬度品质,并且提高了加工鱼糜的稳定性。

To study the effect of suitable dietary iron supplement on the quality of fillet,surimi and Cathepsin B/L(CAT B/L) of Jian carp(Cyprlnus carpio var Jian). The fish fed for 90 days with the supplemented diets containing iron of 146.1 mg/kg(suitable group) was collected as experimental group,and those fed without supplemented diets containing iron of 53.9 mg/kg(lacking group) was the control. After sampling,the quality indexes of fillets and the activities of CAT B/L were detected. Then the protein expression level of CAT B/L was quantified by immunohistochemical analysis. Further,the fillet was processed into surimi,and its stability of each group was measured. The results indicated that the MBF and MFI in suitable group increased or declined slightly(P>0.05) when compared to lacking group. While the shear force of suitable group increased 31.80%(P<0.01);the contents of soluble collagen,insoluble collagen and the total collagen increased 305.45%,180.98%,219.35% respectively(P<0.01). The pH and water loss rate of suitable group was in the trend of decline(P>0.05). Moreover,the CAT B/L activities of suitable group was less than the lacking group to the degree of extreme significance(P<0.01) and significance(P<0.05) respectively. Meanwhile,the immunohistochemical analysis indicated that in both groups,CAT B/L were expressed in the muscle tissue and the expression level of suitable group was less than the lacking group extremely significantly(P<0.01). Additionally it was found that suitable dietary iron supplement could increase the initial CA,TSH(P<0.01),and decrease the initial DB(0.01<P<0.05),PSH and TBA(P<0.01) of Jian carp surimi. In conclusion, the suitable dietary iron supplement could lower the activities and expression level of CAT B/L in muscle of Jian carp;especially, it improved the hardness quality of fillet and the stability of surimi.