混合挥发性脂肪酸钠盐对羔羊小肠消化酶活性及氮沉积的影响

Effects of Mixed Volatile Fatty Acid Sodium Salts on Activities of Intestinal Digestive Enzymes and Nitrogen Retention in Lambs

本文旨在研究混合挥发性脂肪酸钠盐对羔羊小肠食糜消化酶活性及氮沉积的影响。选取15只7周龄、平均体重(13.8±0.8)kg的杂交公羔羊,随机分为5组,每组3只,饲喂代乳料作为基础营养供给。各组分别向代乳料中添加0、5、15、30和60 g/d混合挥发性脂肪酸钠盐(乙酸钠、丙酸钠和丁酸钠的摩尔比为65∶25∶10)。试验期为24 d。在试验期的最后4天,收集粪样和尿样,用于测定粪氮和尿氮。试验结束后将羔羊屠宰,收集小肠食糜,测定小肠食糜中的α-淀粉酶、胰蛋白酶、脂肪酶、糜蛋白酶和半乳糖苷酶的活性。结果表明:添加混合挥发性脂肪酸钠盐对小肠食糜pH、胰蛋白酶、脂肪酶、糜蛋白酶和半乳糖苷酶活性均没有显著影响(P>0.05),对粪氮、尿氮及氮表观消化率也没有显著影响(P>0.05)。30和60 g/d组的α-淀粉酶活性显著低于其他各组(P<0.05)。添加混合挥发性脂肪酸钠盐有增加羔羊氮沉积的趋势(P=0.090)。结果提示,向代乳料中添加30～60 g/d混合挥发性脂肪酸钠盐可降低羔羊α-淀粉酶的活性,有增加氮沉积的趋势,但是对小肠胰蛋白酶、脂肪酶、糜蛋白酶和半乳糖苷酶的活性没有显著影响。

The objective of this trial was to study the effects of mixed volatile fatty acid(VFA) sodium salts on activities of digestive enzymes in intestinal digesta and nitrogen(N) retention in lambs.Fifteen cross-bred male lambs,aged 7 weeks,with an average body weight of(13.8±0.8) kg,were randomly divided into five groups with three lambs in each group.Lambs were all fed milk replacers which provided basal nutrient requirement for them.The supplemental level of mixed VFA sodium salts(molar proportion of acetate,propionate and butyrate was 65∶ 25∶ 10) in each group was 0,5,15,30 and 60 g/d,respectively.The feeding trial lasted for 24 days.At the last four days of the feeding trial,faeces and urine samples were collected for the analysis of faecal N and urinary N.Lambs were slaughtered to collect intestinal digesta for the analysis of pH and activities of α-amylase,trypsin,lipase,chymotrypsin and galactohydrolase.The results showed as follows: no significant difference was found among groups in pH and activities of trypsin,lipase,chymotrypsin and galactohydrolase in intestinal digesta(P>0.05),the same as faecal N,urinary N and N apparent digestibility(P>0.05).Supplementation of mixed VFA sodium salts at 30 and 60 g/d significantly decreased the α-amylase activity(P<0.05),and tended to increase the N retention(P=0.090).It is concluded that supplementation of mixed VFA sodium salts at 30 to 60 g/d can decrease the α-amylase activity,and tends to increase the N retention,whereas activities of intestinal trypsin,lipase,chymotrypsin and galactohydrolase will not be affected.