本试验旨在研究不同限饲水平与营养补偿对小尾寒羊生长性能、消化代谢以和瘤胃液纤维素酶活性的影响。选择体重相近的3月龄小尾寒羊公羊40只,采用单因素4水平随机设计,每组10只,正试期90 d。对照(Ⅰ)组全期自由采食;30 d限饲期内,Ⅱ、Ⅲ和Ⅳ组分别按照NRC(2007)推荐的日增重500、400和300 g/d所需要的代谢能(ME)和粗蛋白质(CP)的量配制饲粮,限饲结束后,试验组自由采食60 d为营养补偿期。在24~30 d和84~90 d进行消化代谢试验。结果表明:1)限饲期,限饲水平对结束体重和平均日增重(ADG)有显著影响(P < 0.05),随限饲水平的升高,结束体重和ADG呈降低趋势,料肉比呈升高趋势。营养补偿期,各组间结束体重无显著差异(P > 0.05);Ⅱ、Ⅲ和Ⅳ组体重补偿百分比分别为对照组的104.36%、101.71%、99.61%;限饲水平对ADG有显著影响(P < 0.05);随限饲水平的升高,ADG呈升高趋势,料肉比呈下降趋势。2)限饲期,限饲水平对干物质(DM)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)的表观消化率有显著影响(P < 0.05),均随限饲水平的升高而降低,而对有机物(OM)、CP的表观消化率无显著影响(P > 0.05)。营养补偿期,组间营养物质的表观消化率差异不显著(P > 0.05)。3)限饲期,限饲水平对食入氮、氮沉积、氮沉积率有显著影响(P < 0.05),均随限饲水平的升高而下降;尿氮/食入氮随限饲水平升高而升高,组间差异不显著(P > 0.05);粪氮和尿氮的变化不显著(P > 0.05)。营养补偿期,组间氮代谢指标差异不显著(P > 0.05)。4)1~30 d,试验组瘤胃液纤维素酶活性呈降低趋势,31~90 d,呈升高趋势,在90 d,试验组均高于对照组。综上所述,对小尾寒羊采用短期适度限饲,经过营养补偿可以使其生长性能、消化代谢不受影响。

The objective of this study was to explore the effects of dietary restriction level and realimentation on growth performance, digestion, metabolism and cellulase activity in ruminal fluid of small tail Han sheep. Forty 3-month old small tail Han sheep with average body weight (BW) of (19.77±1.34) kg were randomly split into four groups with ten sheep in each group by a single factor four levels design. The study lasted for 90 days. Control group (group Ⅰ) was fed ad libitum during the whole period; during 30-day dietary restriction period, three experimental groups were fed diets with different metabolizable energy (ME) and crude protein (CP) levels, which were designed to meet requirements of 500 (group Ⅱ), 400 (group Ⅲ) and 300 g/d (group Ⅳ) of daily gain recommend by NRC(2007), after that, a 60-day realimentation period (ad libitum) was started. Digestion and metabolism tests were carried out on 24 to 30 days and 84 to 90 days, respectively. The results showed as follows: 1) at dietary restriction period, dietary restriction level had significant effects on final BW and average daily gain (ADG) (P < 0.05), with the increase of dietary restriction level, final BW and ADG tended to be decreased, while feed to meat ratio tended to be increased. At realimentation period, final BW was not significantly different among groups (P >0.05); the compensation percentage in BW of groups Ⅱ, Ⅲ and Ⅳ was 104.36%, 101.71% and 99.61% of BW of group Ⅰ; dietary restriction level had significant effect on ADG (P<0.05); with the increase of dietary restriction level, ADG tended to be increased, while feed to meat ratio tended to be decreased. 2) At dietary restriction period, dietary restriction level had significant effects on the apparent digestibility of dry matter (DM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) (P<0.05), and all were decreased with the increase of dietary restriction level, but no significant differences were found for organic matter (OM) and CP apparent digestibility (P >0.05). At realimentation period, the apparent digestibility of all nutrients showed no significant difference among the four groups (P>0.05). 3) At dietary restriction period, dietary restriction level had significant effects on nitrogen intake, nitrogen retention, nitrogen retention percentage (P<0.05), and all were decreased with the increase of dietary restriction level; urinary nitrogen/nitrogen intake tended to be increased with the increase of dietary restriction level, but was not differ significantly (P>0.05). No significant differences of fecal and urinary nitrogen among the four groups were found (P>0.05). At realimentation period, there were no significant differences of the nitrogen metabolism indices among the four groups (P>0.05). 4) On 1 to 30 days, cellulase activity in ruminal fluid of experimental groups tended to be decreased, while on 31 to 90 days, tended to be increased, and on 90 days, all experimental groups were higher than group Ⅰ. The present results indicate that short-term moderate dietary restriction with a realimentation period is not harmful for the growth performance, digestion and metabolism of small tail Han sheep.