【作者】 耿业业；

【导师】 高秀华；

【作者基本信息】 中国农业科学院 ， 动物营养与饲料科学， 2011， 博士

【摘要】 蓝狐是珍贵的毛皮动物之一,属于犬科食肉目,其以消化高蛋白、高脂肪的动物性饲料为主。本课题研究了日粮脂肪类型和水平对蓝狐的消化代谢规律的影响。通过对生产性能、营养物质利用、血清生化指标、消化道酶活、体脂沉积、组织形态学、脂肪代谢相关基因表达等指标的测定,系统的研究脂肪营养素在蓝狐体内的消化、吸收、代谢机理,为饲料的开发与利用、预防和控制脂肪营养素相关疾病提供真实、可靠地科学依据。本文包括两个部分:第一部分脂肪类型对育成期蓝狐消化代谢规律的影响选取日龄相近、体重相近的健康幼狐48只,随机分成3组,每组有8只公狐8只母狐,分别饲喂含不同脂肪类型(鱼油、猪油、牛油)脂肪水平均为12%的试验日粮。结果表明:①鱼油组蓝狐日增重均显著低于猪油和牛油组(P<0.05)。在育成前期,鱼油组蓝狐料肉比和代谢能增重比显著高于其他两组。而在冬毛生长期,各处理组公狐料肉比和代谢能增重比之间存在极显著性差异,以牛油组最低,鱼油组最高(P<0.01)。鱼油组的毛皮质量显著低于其他两组(P<0.05)。②鱼油、牛油和猪油组EE的表观消化率各组之间均存在显著性差异(P<0.05),以猪油组显著优于其他两组。与其他两组相比,蓝狐日粮中添加鱼油可使肠道绒毛变短(P<0.01),隐窝深度加深(P<0.05),而猪油和牛油之间无显著性差异(P>0.05),不同脂肪类型日粮对肠道消化酶活性影响不显著(P>0.05)。③蓝狐鱼油组的TG、TC、HDL-C和LDL-C均表现出较高的浓度,体脂沉积各性状显著升高,尤其是肝脂率和肝体指数(P<0.01),猪油组和牛油组各指标间差异不显著(P>0.05)。猪油和牛油对蓝狐肝脏组织结构未产生不良影响,而鱼油组蓝狐的肝脏组织结构受损伤。④ChREBP基因表达量各组之间存在极显著差异(P<0.01),以鱼油组最高,牛油组最低。鱼油组MTP的基因表达量显著高于其他两组(P<0.05),而猪组与牛油组之间无显著性差异(p>0.05)。鱼油组SREBP-1c基因的表达量极显著低于其他两组(P<0.01),而猪组与牛油组之间无显著性差异(p>0.05)。第二部分日粮脂肪水平对育成期蓝狐消化代谢规律的影响选取日龄相近、体重相近的健康幼狐64只,随机分成4组,每组有8只公狐8只母狐,分别饲喂脂肪水平约为12%、26%、40%和54%的试验日粮。结果表明:①随日粮脂肪含量的增加日采食量和料肉比逐渐降低,日采食代谢能有先增加后保持平衡的趋势,40%组日采食代谢能极显著高于12%组(P<0.01)。公狐以26%组,母狐以40%组生长最快。毛皮质量各指标随着日粮脂肪含量的增加有先增加后降低的趋势,26%组公狐极显著优于其他三组(P<0.01),54%组母狐极显著均劣于其他三组(P<0.01)。②整个育成期,除碳水化合物外的各营养物质的利用率都随着日粮脂肪水平的增加呈逐渐上升趋势。12%组CP、EE、DM和GE的消化率极显著低于40%和54%组(P<0.01)。随着日粮脂肪含量的增加氮摄入量、粪氮、尿氮逐渐降低,NPU和BV有上升趋势。日粮中较高的脂肪水平会引起蓝狐肠道形态学上的改变,使小肠绒毛变短,隐窝加深,同时脂肪酶活性增大,但对胰蛋白酶和淀粉酶活性没有影响。③日粮脂肪水平为54%时,蓝狐体脂沉积各性状显著升高尤其是肝脂率和肝体指数(P<0.05),并出现高血脂高血糖现象,肝脏组织结构受损严重。血清TG和HDL-C可初步作为生长蓝狐肝脏脂肪侵润程度、肝体指数及内脏脂肪含量的预测指标。④MTP基因表达量随着脂肪水平的增高明显增高的趋势,以54%组极显著高于其他组(P<0.01),40%组极显著高于12%和26%组(P<0.01),而12%和26%组两组间无显著差异(P>0.05)。综上所述,本文认为育成期蓝狐日粮适宜脂肪水平为26%;日粮中过高脂肪含量会引起蓝狐病变;MTP基因表达量随着脂肪水平的增高明显增高的趋势。鱼油组多数生理、生产指标显著低于牛油和猪油,而牛油和猪油组间无差异;鱼油组肝脏SREBP-1c基因的表达量显著低于其他两组,但组织形态学观察鱼油组肝脏受损,因此不建议在此时期单独添加鱼油。更多还原

【Abstract】 Blue foxes (Alopex lagopus) are well-known carnivorous mammals of the Canidae family and are precious fur-bearing animals. They mainly live on animal feedstuff of high protein and high fat. This study focused on the effects of dietary lipid levels and fat species on the nutrient absorption and metabolism in Blue foxes.Hopefully, this paper could provide a reliable basis for development and utilization of fodder as well as prevention and control of fat related disease by determination of reproductive performance, nutrient utilization, serum biochemical indices, digestive tract enzyme activity, fat deposition, tectology and genes expression of lipid metabolism and systematic research of the assimilation and metabolism mechanism of fat. The dietary lipid levels are 12%。The paper consists of two parts:PartⅠThe Effect Of Different Fat On Digestion And Metabolism Of Blue Foxes In Growing Period48 larva foxes, which were healthy, and roughly the same age and body weight, were allotted into 3 treatments randomly, each treatment consisted of 8 male and 8 female, fed with diet containing fish oil, lard and tallow seperately.①Blue foxes fed with diet containing fish oil had the lowest daily weight gain, which was significantly lower than the ones fed with diet containing lard and tallow(P<0.05). Feed conversion ratio and energy/gain ratio of fish oil group were significantly higher than the other two groups during the early growing period. However the male blue foxes of the three groups showed extremely significant differences in feed conversion ratio and energy/gain ratio, with the lowest in fish oil group and highest in tallow group(P<0.01).the fish oil fed group had the significant poorer fur quality compared with the other two(P<0.05).②Comparing with the other two treatments, diets with fish oil can shorten the intestinal mucosae(P<0.01) and deepen the recess(P<0.05). The treatments with lard and tallow showed no significant differences (P>0.05).All type of dietary had no significant effect on activity of intestinal digestive enzyme.③The TG, TC, HDL-C and LDL-C of blue foxes in fish oil treatment all with high on centration, the index of fat deposition were significantly raised especially the hepatic fat rate and liver/body ratio(P<0.01). The treatments with lard and tallow showed no significant differences in these indexes (P>0.05). Lard and tallow had no bad effects on liver while the fish oil caused damage to the structure of liver.④Extremely significant difference was observed in expression quantity of ChREBP,reaching the highest in fish oil group and lowest in tallow group(P<0.01). The expression quantity of MTP in group fed with fish oil contained diet was significantly higher than those of lard group and tallow group (P<0.05), between which no significant differences were observed (p>0.05). The expression quantity of SREBP-1c in group fed with fish oil contained diet was significantly lower than those of lard group and tallow group (P<0.01),between which no significant differences were observed (p>0.05).PartⅡThe Affect of Fat Level On Digestion and Metabolism In Blue Foxes In Growing Period 64 larva foxes, which were healthy, and roughly the same age and body weight, were allotted into 4 treatments randomly, each treatment consisted of 8 male and 8 female, fed with diet containing 12%、26%、40% and 54% fat.①Average daily feed intake and feed conversion ratio decreased as the dietary fat increased, d metabolizable energy tended to increase at first then remained stable. The daily metabolizable energy of 40% treatment was significantly higher than 12% treatment (P<0.01). Male foxes in 26% treatment and female in 40% treatment grew most rapidly.As the fat in dietary increased, pelt quality increased at first and then decreased. Pelt quality of male foxes in 26% treatment was significantly better than other treatments (P<0.01) while that of female in 54% treatment was significantly worse than other treatments (P<0.01).②The nutrient-use efficiency increased as the dietary lipid level rose except carbohydrate during growing period. The digestibilities of crude protein, ether extract, dry matter and gross energy of 12% treatment was significantly lower than those of treatment 40% and 54%.As the fat in dietary increased, there was a decline of nitrogen intake, fecal nitrogen and urinary nitrogen, while net protein utilization and biological value of protein increased. High level of fat in dietary would cause morphological change in intestinal canal such as shorter intestinal villi, deeper recess and more lipase activity, but trypsinase and amylopsin were not affected.③With 54% fat in dietary, the index of fat deposition were significantly raised especially the hepatic fat rate and liver/body ratio (P<0.05), hyperlipoidemia and hyperglycosemia were detected, the liver was badly damaged.The TG and HDL-C of serum can be preliminary predictive index of degree of liver fat accumulation, liver/body ratio and visceral adiposity in blue foxes in growing period.④In sum, this study suggested optimum dietary fat level of blue fox in growing period is 26%.④The expression quantity of MTP increased with the fat level and the 54% group was extremely significantly higher than the other groups(P<0.01), 40% group was extremely significantly higher than 12% and 26% group(P<0.01).No significant difference was observed between 12% and 26% group(P>0.05).In conclusion, based on this study, the optimum dietary fat level in blue foxes of growing-furring period is 26%, higher fat level could cause pathological changes. The expression quantity of MTP increased with the fat level. Feeding effect of lard and tallow were equally good. Most physiological performance and production performance of fish oil group were significantly lower than those of lard group and tallow group, between which no significant differences were observed. The expression quantity of SREBP-1c in liver in group fed with fish oil contained diet was significantly lower than those of other groups, but the liver of foxes in fish oil group were morphologically damaged, so fish oil was not recommended at this period.更多还原