Department of Animal and Fish Production, Faculty of Desert and Environmental Agriculture, Matrouh University, Matrouh, Egypt.
North Carolina Agricultural and Technical State University, Greensboro, North Carolina, USA.
J Anim Physiol Anim Nutr (Berl). 2022 Mar;106(2):229-238. doi: 10.1111/jpn.13577. Epub 2021 Jun 1.
This experiment aimed to investigate the effects of substituting barley grain with discarded dates on intake and digestibility, nitrogen (N) utilization and fermentation characteristics of sheep fed Atriplex hay-based diets. Four Barki sheep (50.9 ± 2.93 kg of body weight (BW)) fitted with rumen cannula were used in a 4 × 4 Latin Square design with 23-day periods. Four isonitrogenous (~140 g crude protein (CP)/kg of dry matter (DM)) experimental diets were formulated with Atriplex hay, and dietary sugar content was increased by replacing barley grain with discarded dates (the proportions of discarded dates in the diet were 0, 93, 187 and 280 g/kg DM). Nutrient intakes were not influenced by diet. Organic matter, CP and neutral detergent fibre digestibility increased (p < 0.05) linearly and DM digestibility tended to increase with increased dates inclusion. Ruminal pH and molar proportion of butyrate increased (p < 0.05) linearly with increasing levels of dates inclusion, whereas ruminal ammonia-N decreased (p < 0.05) linearly. Total volatile fatty acid concentration was unaffected. Microbial protein synthesis (MCP) increased linearly and efficiency of microbial protein synthesis tended to increase as discarded dates increased. Total N intake was not affected by diets whereas, urinary N, urea-N and total N execrations linearly decreased (p < 0.05) with higher amounts of dates in the diets. Blood urea-N tended to decrease with increasing levels of dates. It could be concluded that replacing 100% barley grain with discarded dates as a source of soluble carbohydrates can enhance the utilization of N in Atriplex hay-based diet and consequently improve digestibility and MCP.
本试验旨在研究用废弃的枣代替大麦粒对以滨藜干草为基础的日粮绵羊采食量、消化率、氮（N）利用率和发酵特性的影响。4 只安装有瘤胃瘘管的 Barki 绵羊（50.9±2.93kg 体重（BW））采用 4×4 拉丁方设计，试验期为 23 天。4 种等氮（~140g 粗蛋白（CP）/kg 干物质（DM））的试验日粮用滨藜干草配制，通过用废弃的枣替代大麦粒来增加日粮中的糖含量（日粮中废弃枣的比例分别为 0、93、187 和 280g/kg DM）。日粮对养分采食量没有影响。有机物、CP 和中性洗涤纤维消化率呈线性增加（p<0.05），DM 消化率随着枣用量的增加而呈上升趋势。随着枣用量的增加，瘤胃 pH 和丁酸摩尔比例呈线性增加（p<0.05），而瘤胃氨态氮呈线性下降（p<0.05）。总挥发性脂肪酸浓度不受影响。微生物蛋白合成（MCP）呈线性增加，随着废弃枣的增加，微生物蛋白合成效率呈上升趋势。日粮对总 N 摄入量没有影响，而尿液 N、尿素 N 和总 N 排泄量随日粮中枣用量的增加呈线性下降（p<0.05）。血液尿素氮有随枣用量增加而下降的趋势。可以得出结论，用废弃的枣替代 100%的大麦粒作为可溶性碳水化合物的来源，可以提高滨藜干草日粮中 N 的利用率，从而提高消化率和 MCP。
