Digestibility, ingestive behavior, and nitrogen balance in goat kids fed a diet containing dehydrated passion fruit residue

ABSTRACT The objective was to determine the optimal dehydrated passion fruit pulp replacing ground corn in diets for goat kids. We used 24 crossbred castrated goat kids with initial body weight of 26.6±0.3 kg. The experimental period was 23 days, with 15 days of adjustment and acclimatization (mostly to the installation and diet). Kids were distributed in a randomized experimental design with four treatments of 0, 80, 160, or 240 g/kg of dehydrated passion fruit residue as a supplementary inclusion in the dry matter (DM) content of the diet. The statistical model considered the fixed effect of the included amount of residue from dehydrated passion fruit. Analysis of variance was conducted using the PROC GLM of SAS. Intakes of DM and total digestible nutrients (TDN) were not affected by residue inclusion. However, neutral detergent fiber (NDF) intake increased linearly. The inclusion linearly decreased intake of ether extract (EE) and non-fibrous carbohydrates (NFC). Crude protein (CP) intake was quadratically affected, with a greater value under treatment of 160 g/kg passion fruit. Dry matter and NFC digestibility decreased linearly with the amount of passion fruit included in diet. Fecal N and total N excretion values (in g/d and %N intake) increased linearly. Nitrogen balance and N retained values showed a quadratic increase, with greater values under the 160 g/kg inclusion. Time spent ruminating, DM and NDF eating efficiency, and g DM/bolus chewed were affected quadratically by inclusion of passion fruit residue. The replacement of ground corn with dehydrated passion fruit residue at a level of 160 g/kg is recommended for diets of goat kids to improve their NDF and CP intake and their N balance without affecting DM and TDN intakes.

摘要 本试验旨在探究脱水西番莲果浆替代磨碎玉米在山羊羔日粮中的最优添加比例。试验选用24只初始体重为26.6±0.3 kg的杂交去势山羊羔，试验周期共23天，其中包含15天的适应驯化期（主要适应圈舍环境与试验日粮）。采用随机试验设计，设置4个处理组，分别在日粮干物质（dry matter, DM）中添加0、80、160、240 g/kg的脱水西番莲果残渣作为补充料。统计模型考虑脱水西番莲果残渣添加量的固定效应，采用SAS软件的PROC GLM过程进行方差分析。结果显示，干物质（DM）与总可消化养分（total digestible nutrients, TDN）的采食量不受残渣添加量的影响；但中性洗涤纤维（neutral detergent fiber, NDF）采食量呈线性升高。粗脂肪（ether extract, EE）与非纤维碳水化合物（non-fibrous carbohydrates, NFC）的采食量则随添加量线性下降。粗蛋白质（crude protein, CP）采食量呈二次效应变化，在160 g/kg处理组中数值最高。日粮中脱水西番莲果残渣的添加量会使干物质与NFC的消化率呈线性降低。粪便氮与总氮排泄量（以g/d和占氮摄入的百分比计）呈线性升高。氮平衡与氮留存量呈二次升高趋势，在160 g/kg添加组中数值最高。反刍时长、干物质与中性洗涤纤维的采食效率，以及每咀嚼食团的干物质克数均受残渣添加量的二次效应影响。综上，推荐在山羊羔日粮中以160 g/kg的比例用脱水西番莲果残渣替代磨碎玉米，可在不影响干物质与总可消化养分采食量的前提下，提升其中性洗涤纤维与粗蛋白质采食量以及氮平衡水平。