蛋氨酸限制与补偿对羔羊生长性能及内脏器官发育的影响

本试验旨在研究蛋氨酸限制与补偿对羔羊生长性能及内脏器官发育的影响。选取12对1周龄断奶的湖羊双胞胎公羔羊,采用配对试验设计,每对双胞胎羔羊分别分到2组中。第1阶段,2~8周龄,分别补充[基础代乳粉+0.70%蛋氨酸,基础开食料+0.40%蛋氨酸,对照(control,CON)组]和限制蛋氨酸[基础代乳粉,基础开食料,限制(restriction,RES)组];第2阶段,9~12周龄,2组羔羊饲喂相同的饲粮(基础开食料+0.40%蛋氨酸)。在8和12周龄末,各选取6对双胞胎羔羊进行屠宰,分离内脏器官并称重。结果表明:1)8周龄,RES组的体重显著低于CON组(P0.05);2~8周龄,RES组平均日增重极显著低于CON组(P0.01),而RES组料重比显著高于CON组(P0.05);9~12周龄,2组平均日增重和料重比均无显著差异(P0.05)。2)8周龄,RES组的宰前活重、空体重、胴体重均显著低于CON组(P0.05),但2组间的屠宰率无显著差异(P0.05);12周龄,RES组和CON组宰前活重、空体重、胴体重、屠宰率均无显著差异(P0.05)。3)8和12周龄,2组的各内脏器官在重量、占宰前活重比例均无显著差异(P0.05)。4)8周龄,RES组的瘤胃重量显著低于CON组(P0.05),其余各胃肠道指数均无显著差异(P0.05);12周龄,2组间各胃肠道指数也无显著差异(P0.05)。由此可见,限制饲粮蛋氨酸水平降低了羔羊瘤胃重量、生长性能和屠宰性能,恢复饲粮蛋氨酸水平后,羔羊生长性能及内脏器官发育状况也随之恢复。

Effects of Dietary Methionine Restriction and Compensation on Growth Performance and Visceral Organ Development of Lambs

The aim of this study was to assess the effects of dietary methionine ( Met) restriction and compen?sation on growth performance and visceral organ development of lambs. Twelve pairs of male Hu twin lambs weaned at one week of age were selected and divided into two groups with a matched?pairs design. During 2 to 8 weeks of age, lambs were fed diets containing either sufficient [ basal milk replacer+0.70% Met and basal starter+0.40% Met, control ( CON) group] or deficient Met [ basal milk replacer and basal starter, restriction ( RES) group] . During 9 to 12 weeks of age, all lambs were fed diets containing sufficient Met ( basal starter+ 0.40% Met) . Six twins each time were slaughtered at the end of 8 and 12 weeks of age for weighting viscer?al organs, respectively. The results showed as follows:1) body weight of 8?week?old lambs in RES group was significantly lower than that in CON group ( P<0.05);average daily gain in RES group was significantly lower than that in CON group during 2 to 8 weeks of age (P<0.01), whereas feed to gain ratio was significantly higher ( P<0.05); no significant differences were found in average daily gain and feed to gain ratio between two groups during 9 to 12 weeks of age ( P>0. 05 ) . 2 ) Live body weight before slaughter, empty body weight, carcass weight of 8?week?old lambs in RES group were significantly lower than those in CON group ( P<0.05) , but no significant difference was found in dressing percentage between two groups ( P>0.05);no significant differences were observed in live body weight before slaughter, empty body weight, carcass weight, and dressing percentage between groups at 12 weeks of age ( P>0.05) . 3) No significant differences were ob?served in weights and percentages of live body weight before slaughter of visceral organs between groups at 8 and 12 weeks of age (P>0.05). 4) No significant differences were observed in gastrointestinal tract indexes between groups at 8 and 12 weeks of age ( P>0.05) except rumen weight at 8 weeks of age, which was signif?icantly lower in RES group than in CON group (P<0.05). In conclusion, dietary restriction of Met level re?sults in decreased rumen weight, growth performance and slaughter performance of lambs, but subsequent re?coveries of growth performance and visceral organ development appear after the compensation of dietary Met level.