本试验旨在研究不同中性洗涤纤维(NDF)水平饲粮对肉羊生长性能和营养成分表观消化率的影响,以确定肉羊饲粮中最佳NDF水平。试验动物为杜寒杂交(黑头杜泊羊×小尾寒羊)F₁代肉用绵羊,采用单因素完全随机区组试验设计,将体重相近的50只母羊和25只公羊随机分为5个处理,每个处理10只母羊和5只公羊,每5只为1个重复,公母分圈饲养。5组试验羊饲喂粗蛋白质水平同为14.8%,而NDF水平分别为26.51%、33.35%、38.71%、43.51%、48.35%的试验饲粮,考察试验羊的生长性能,并在体重达到30 kg左右时进行为期4 d的粪袋全收粪试验,测定饲粮营养成分的表观消化率。试验期为48 d。结果表明:1)不同NDF水平的饲粮对试验羊净增重、平均日增重没有显著影响(P>0.05),试验羊的性别对净增重、平均日增重有显著影响(P<0.05)。试验羊增重效果表现为33.35%组>26.51%组>38.71%组>43.51%组>48.35%组。2)试验羊的干物质采食量与饲粮NDF水平呈现正相关关系(R²=0.744 6),并且48.35%组显著或极显著高于26.51%、33.35%和38.71%组(P<0.05或P<0.01)。饲粮NDF水平显著影响试验羊的料重比(P<0.05),以33.35%组最低,48.35%组最高。3)饲粮NDF水平对干物质、有机物、粗蛋白质、粗脂肪、NDF和酸性洗涤纤维的表观消化率存在极显著影响(P<0.01),各营养成分表观消化率均以33.35%组为最高。综合考虑生长性能和营养成分表观消化率,在粗蛋白质水平为14.8%的肉羊饲粮中,最佳NDF水平为33.35%。

This experiment was conducted to investigate the effects of diets with different neutral detergent fiber (NDF) levels on growth performance and nutrient apparent digestibility of meet sheep, and to determine dietary optimal NDF level of meat sheep. This experiment was performed with hybrid F₁ sheep of Black Head Dorper sheep譙mall Tail Han sheep. Fifty female lambs and twenty-five male lambs with the similar body weight were randomly assigned to five groups with ten female lambs and five male lambs each group (five lambs per replicate) by a single factor completely randomized block design. Female and male lambs were separated to feed. Each group was fed one of the five experimental diets which had the same crude protein level (14.8%) and different NDF levels. The NDF levels of the five experimental diets were 26.51%, 33.35%, 38.71%, 43.51% and 48.35%, respectively. Growth performance was measured, and the nutrient apparent digestibility was determined by a 4-day digestive trial which was conducted after the body weight of sheep reached about 30 kg. The experiment lasted for 48 days. The results showed as follows: 1) there were no significant effects on net weight gain and average daily gain of sheep fed diets with different NDF levels (P>0.05), but sex of sheep played a significant role on those (P<0.05). The order of weight gain effect was 33.35% group>26.51% group>38.71% group>43.51% group>48.35% group. 2) Dry matter intake of sheep had a positive correlation with dietary NDF level (R²=0.744 6), and showed a significant difference between 48.35% group and 26.51%, 33.35% or 38.71% groups (P<0.05 or P<0.01). Dietary NDF level had a significant effect on feed/gain (P<0.05), the 33.35% group was the lowest and the 48.35% group was the highest. 3) Dietary NDF level had significant effects on apparent digestibility of dry matter, organic matter, crude protein, ether extract, NDF and acid detergent fiber (P<0.01), and the highest values of them were all found in 33.35% group. Through a comprehensive consideration of growth performance and nutrient apparent digestibility, this experiment recommen 33.35% as the optimal dietary NDF level of meat sheep when dietary protein level is 14.8%.