不同断奶日龄对舍饲肉用羔羊前胃功能发育的影响

Effects of different weaned day of age on functional development of forestomach for confined lambs

选用甘肃肉用羊新品种育种群出生公羔(单羔)55只,分为3个处理组,其中28、42d断奶组各15只,对照组(不断奶)25只.供试羔羊生后均哺食母乳,于7日龄开始补饲.2个断奶组羔羊均于断奶后0、7、14d屠宰,测定前胃各室内容物的相对质量、pH、瘤胃内容物的脂肪酸(VFA)浓度及与总挥发性脂肪酸的比值、主要微生物消化酶比活性等指标.结果表明:对照组羔羊在35d、断奶组羔羊在断奶日瘤网胃内容物占全胃内容物质量相对质量均达到成年羊水平,早期断奶对其未产生显著影响(P>0.05).断奶组与未断奶组羔羊各时段瘤胃、网胃和瓣胃内容物pH均相对稳定,断奶未对其产生明显影响(P>0.05).断奶与否对TVFA和各种酸的浓度无明显影响,所有处理的TVFA浓度均居较高水平,呈随日龄增长的趋势.断奶组羔羊瘤胃内容物微生物蛋白酶活性在断奶后7d和14d上升较快,但仍低于对照组对应日龄;断奶使微生物蛋白活性降低,日龄越小受影响越大,但恢复能力强.断奶可促使微生物淀粉酶活性增强,且断奶日龄越小增幅越大.断奶对纤维酶比活性有影响.舍饲并于7日龄开始补饲条件下,42日龄断奶羔羊调节前胃功能的能力较强,28日龄断奶应激较大,但羔羊可在较短的时间内消除断奶引起的不良影响.

The objective of this study was to investigate the effects of different weaned day of age on functional development of forestomach for confined lambs.Fifty-five male lambs（Gansu modern breeding sheep group,singleton） were divided into 3 treatments,15 animals were used in group A（weaned at 28 days of age）and B（weaned at 42 day of age） respectively,25 suckling lambs were used in group C（control）.All lambs were raised in the supplementary feed from the age of 7 days.Killed and sampled from the group A and B at 0,7,14 days after weaned,and from the control（5 lambs） at the same time respectively.The weight and pH value of contents in every compartment of forestomach,concentration and proportion of volatile fatty acids and activities of microbic enzymes for rumen contents were measured respectively.The results indicated that the weight of contents（% total weight of content for stomach） in control groups at 35 day of age and weaned groups at the weaned days were all close to that in the adult sheep,and there weren＇t significant influence for those by weaned（P0.05）.The pH values of contents for every compartment for forestmoach were relatively stable in all animals at every determined time,and there weren＇t seemingly effect for that by weaned（P0.05）.There were no significant effect on concentration of TVFA and every kind of volatile fatty acid.The concentration of TVFA were all at high level in every group and had a trend to promote with the age increasing.The activities of protease for rumen contents was obviously increased at 7 and 14 day after weaned,but that in weaned groups was lower than that in control respectively.Although it was reduced by weaned and the effect was serious of group A than that of group B,the ability of recovery of group A was stronger than that of group B.The activities of α-amylase were enhanced by weaned and the range was increased stronger of group A than that of group B.The activities of cellulose was affected by weaned（P0.05）.The conclusion indicated that the ability of regulated the function for forestomach of group B was stronger than that of group A,with raised and supplied the suited supplementary diet from 7 d after birth.Although the stress of group A was appeared seriously than that in gorup B,animals could recover during a shorter time.