颗粒饲料中小麦添加比例对青海藏羊生长性能与肠道发育的影响

Effect of wheat ratios added to pellet feed on growth performance and intestinal development of Qinghai Tibetan sheep

【目的】研究颗粒饲料中小麦添加比例对青海藏羊生长性能、小肠形态发育及空肠消化酶活性、免疫机能和抗氧化指标的影响。【方法】选择90只体质量相近((21.87±2.35)kg/只)、发育良好的3月龄高原型藏羊,随机分为3组,每组6个重复,每个重复5只羊,分别饲喂小麦质量分数为0%(对照组)、10%(试验Ⅰ组)、15%(试验Ⅱ组)的颗粒饲粮,饲喂试验为期90 d。饲养试验结束后,测算平均日增重(ADG)、平均日采食量(ADFI)和料重比(F/G);从每组中随机挑选5只羊进行屠宰,采集小肠各段(十二指肠、空肠和回肠)制备石蜡切片,测量绒毛高度(VH)、绒毛宽度(VW)、隐窝深度(CD)和肌层厚度(MT),并计算绒毛高度/隐窝深度(绒隐比,V/C);测定空肠食糜α-淀粉酶、纤维素酶(CE)、糜蛋白酶、脂肪酶、胰蛋白酶(TPS)活性,免疫球蛋白A(immunoglobulin A,IgA)、IgG、IgM、白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)质量浓度及抗氧化特性(超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性,丙二醛(MDA)浓度及总抗氧化能力(T-AOC))。【结果】①试验Ⅱ组藏羊的终末体质量、平均日增重显著小于对照组(P<0.05),而料重比显著大于对照组(P<0.05)。②试验Ⅰ组藏羊的十二指肠VW显著高于对照组(P<0.05),对照组的十二指肠MT显著高于试验Ⅱ组(P<0.05);试验Ⅰ组藏羊的空肠VH、V/C显著高于对照组(P<0.05),试验Ⅰ组藏羊的空肠MT显著高于其余2组(P<0.05);各组藏羊间回肠的VH、VW、CD、MT及V/C差异均不显著(P>0.05)。③试验Ⅰ组藏羊的空肠CE、糜蛋白酶及TPS活性显著高于其余2组(P<0.05),对照组的空肠α-淀粉酶活性显著低于其余2组(P<0.05),各组间空肠的脂肪酶活性差异不显著。④试验Ⅰ组藏羊的空肠IgA、IgG质量浓度显著高于试验Ⅱ组(P<0.05),各组间空肠的IgM、IL-1β和TNF-α质量浓度差异不显著(P>0.05)。⑤对照组藏羊的空肠T-AOC及GSH-Px、CAT、SOD活性显著低于试验Ⅰ组(P<0.05),各组间空肠的MDA浓度差异不显著(P>0.05)。【结论】颗粒饲料中小麦质量分数为10%时,不会损害青海藏羊的生长发育,且会显著提高小肠发育能力、空肠抗氧化能力及免疫机能和消化酶活性,可考虑在藏羊育肥中推广应用。

【Objective】This experiment investigated the effects of wheat supplemental proportion in pellet diet on growth performance,morphology of small intestine,digestive enzyme activities,immune function and antioxidant indexes of jejunum in Qinghai Tibetan sheep.【Method】Ninety 3-month-old plateau Tibetan sheep with similar body weight of((21.87±2.35)kg)were randomly divided into 3 groups with 6 replicates per group and 5 sheep per replicate,which were fed pellet diets with 0%(control group),10%(Ⅰgroup)and 15%(Ⅱgroup)wheat,respectively.The trial lasted for 90 days after a 15-day adaption.At the end of the feeding experiment,average daily gain(ADG),average daily feed intake(ADFI)and feed to gain(F/G)were measured.Five sheep were randomly selected from each group and slaughtered,each segment of small intestine(duodenum,jejunum and ileum)was collected for paraffin section,villus height(VH),villus width(VW),crypt depth(CD)and muscular thickness(MT)were measured,and the villus height/crypt depth(V/C)was calculated.The contents ofα-amylase,cellulase,chymotrypsin,lipase,tryp-sin(TPS),immunoglobulin A(IgA),IgG,IgM,IL-1β,TNF-αand antioxidants(SOD,GSH-Px,CAT,MDA and total antioxidant capacity(T-AOC))of jejunal chyme were measured.【Result】①The final body weight and average daily gain ofⅡgroup were significantly lower than those of control group(P<0.05),while the ratio of feed to gain was significantly higher(P<0.05).②The VW of duodenum inⅠgroup was higher than that in control group(P<0.05).The MT of duodenum in control group was higher than that inⅡgroup(P<0.05).The VH and V/C of jejunum inⅠgroup was significantly higher than that in control group(P<0.05).The jejunum MT inⅠgroup was significantly higher than that in the other groups(P<0.05),while there were no significant differences in VH,VW,CD,MT and V/C in ileum among all groups(P>0.05).③The activities of CE,chymotrypsin and TPS in jejunum ofⅠgroup were significantly higher than those of other groups(P<0.05).The activity ofα-amylase in jejunum of control group was significantly lower than that of other groups(P<0.05),while there was no significant diffe-rence in lipase activity of jejunum among all groups.④The contents of IgA and IgG in jejunum ofⅠgroup were higher than those ofⅡgroup(P<0.05).The contents of IgM,IL-1βand TNF-αin jejunum were not significantly different among all groups(P>0.05).⑤The T-AOC,GSH-Px,CAT and SOD activities in jejunum of control group were significantly lower than those inⅠgroup(P<0.05).The content of MDA in jejunum of control group had no significant difference among all groups(P>0.05).【Conclusion】The addition of 10%wheat in pellet diet had no damage on the growth performance of Qinghai Tibetan sheep,but significantly improved development ability of small intestine,antioxidant capacity,immune function and digestive enzyme activities of jejunum.Thus,it can be widely applied in Tibetan sheep fattening.