饲粮消化能和可消化粗蛋白质水平对燕山绒山羊营养物质表观消化率的影响

Effects of Dietary Digestible Energy and Digestible Crude Protein Levels on Nutrient Apparent Digestibility of Yanshan Cashmere Goats

本试验旨在研究饲粮消化能(DE)和可消化粗蛋白质(DCP)水平对舍饲燕山绒山羊公羔营养物质表观消化率的影响。选择体况良好、体重为(16.17±1.90) kg的4月龄断奶燕山绒山羊公羔90只,随机分为9组,每组10只。试验采用3×3完全随机设计,DE设定低(11.6 MJ/kg)、中(12.8 MJ/kg)、高(14.0 MJ/kg) 3个水平,DCP也设定低(8.5%)、中(9.5%)、高(10.5%) 3个水平,共配制9种饲粮。每组试验羊随机饲喂1种饲粮,当试验羊平均体重达到20 kg时,每组选择4只进行消化代谢试验,预试期7 d,正试期3 d。结果显示:1)随着饲粮DE水平的升高,粪能显著降低(P<0.05),总能表观消化率显著提高(P<0.05);饲粮DCP水平和DE水平与DCP水平的交互作用对摄入总能、粪能、尿能、消化能和总能表观消化率均未产生显著影响(P>0.05)。2)摄入氮和粪氮随饲粮DE水平的升高而显著降低(P<0.05);低、中DE水平组的氮表观消化率显著低于高DE水平组(P<0.05);低DCP水平组的摄入氮和氮表观消化率显著低于高DCP水平组(P<0.05),低、中DCP水平组的可消化氮显著低于高DCP水平组(P<0.05);饲粮DE水平与DCP水平的交互作用对各氮代谢指标均无显著影响(P>0.05)。3)随着饲粮DE水平的升高,干物质、有机物、粗脂肪和钙的表观消化率逐渐提高,其中干物质、有机物的表观消化率表现为各组间差异显著(P<0.05),粗脂肪的表观消化率表现为高DE水平组显著高于低DE水平组(P<0.05),钙的表观消化率表现为高、中DE水平组显著高于低DE水平组(P<0.05);饲粮DCP水平以及DE水平与DCP水平的交互作用对干物质、有机物、粗脂肪、中性洗涤纤维、酸性洗涤纤维、钙和磷的表观消化率均未产生显著影响(P>0.05)。综上所述,随着饲粮DE水平的提高,燕山绒山羊的干物质、有机物、粗脂肪、钙、总能和氮的表观消化率持续提高;饲粮DCP水平显著影响了燕山绒山羊的摄入氮、消化氮和氮表观消化率;饲粮DE和DCP水平分别为14.0 MJ/kg和10.5%时燕山绒山羊的总能表观消化率、消化能、氮表观消化率最高,DE和DCP水平分别为12.8 MJ/kg和10.5%时燕山绒山羊的沉积氮最高。

The objective of this study was to evaluate the effects of dietary digestible energy(DE)and digestible crude protein(DCP)levels on nutrient apparent digestibility of Yanshan cashmere goats under stall-feeding condition.Ninety 4-month-old weaned male Yanshan cashmere goats with good body condition and body weight of(16.17±1.90)kg were divided into 9 groups with 10 goats per group.Nine diets were formulated according to a 3×3 completely random experiment design,in which DE were designed at 3 levels and they were low(11.6 MJ/kg),medium(12.8 MJ/kg)and high(14 MJ/kg),DCP were also designed at 3 levels and they were low(8.5%),medium(9.5%)and high(10.5%).Goats in each group randomly fed one of nine diets.Four lambs per group were selected for a digestion and metabolism trial after the lambs in each group reached 20 kg of average body weight,and the pretrial and trial lasted for 7 and 3 days,respectively.The results showed as follows:1)the fecal energy(FE)was significantly decreased with the increase of dietary DE level(P<0.05),but the gross energy(GE)was significantly increased(P<0.05).Dietary DCP level and the interaction of DE level and DCP level had no significant effects on GE,FE,urinary energy(UE),DE and GE apparent digestibility.2)The nitrogen(N)intake and fecal N were significantly decreased with the increase of dietary DCP level(P<0.05).N apparent digestibility in low and medium DE level groups was significantly higher than that in high DE level group(P<0.05).The N intake and N apparent digestibility in low DCP level group was significantly lower than those in high DE level group(P<0.05).The digestible N in low and medium DCP level groups was significantly lower than that in high DE level group(P<0.05).The interaction of DE level and DCP level had no significant effects on N metabolism indices(P>0.05).3)The apparent digestibility of dry matter(DM),organic matter(OM),calcium(Ca)and ether extract(EE)were gradually increased with the increase of dietary DCP level(P<0.05).The apparent digestibility of DM and OM showed significant difference among groups(P<0.05),the apparent digestibility of EE in high DE level group was significantly higher than that in low DE level group(P<0.05),and the apparent digestibility of Ca in high and medium DE level groups was significantly higher than that in low DE level group(P<0.05).Dietary DCP level and the interaction of DE level and DCP level had no significant effects on the apparent digestibility of DM,OM,EE,neutral detergent fiber(NDF),acid detergent fiber(ADF),Ca and phosphorus(P).In conclusion,the apparent digestibility of DM,OM,EE,Ca,GE and N are increased continuously with the increase of dietary DE level,and dietary DCP level significantly affects the N intake,digestible N and N apparent digestibility of Yanshan cashmere goats.DE and the apparent digestibility of GE and N of Yanshan cashmere goats are highest in the diet with 14 MJ/kg DE and 10.5%DCP,and the N retention is highest of Yanshan cashmere goats in the diet with 12.8 MJ/kg DE and 10.5%DCP.