Takahashi T, Sakaguchi E
Laboratory of Animal Nutrition, Faculty of Agriculture, Okayama University, Japan.
J Comp Physiol B. 1998 May;168(4):281-8. doi: 10.1007/s003600050147.
To estimate the contribution of coprophagy to protein intake, we observed the behavior, particularly that associated with coprophagy, in adult and young captive nutrias (experiment 1), and analyzed chemical composition and amino acid composition, including diaminopimeric acid (DAP), an indication of bacterial-deprived protein, of soft feces, entire hard feces, and the black part and green part of hard feces (experiment 2). Nutrias practiced coprophagy 48 times per 24 h in adults, and 28 times in young animals, which not only had a 24-h rhythm but also had 1-h or 2-h short-term rhythms. Nutrias ingested food and drank water vigorously after sunset, following which they practiced coprophagy from midnight to morning, before lying down for much of the day. When coprophagy was prevented we sampled soft feces, produced from midnight to noon, which had high (P < 0.05) concentration of crude protein (CP), DAP on a dry matter (DM) basis and 13 amino acids on a 16 g N basis than hard feces, and had a low (P < 0.05) content of acid detergent fiber (ADF). CP was greater in the black part than the green part of hard feces (P < 0.05) although ADF was less (P < 0.05). The chemical composition of the black part of hard feces was not significantly different from that of soft feces. The dry weight of soft feces excreted in experiment 1 was 34.5 g and 9.7 g DM per 24 h in adult and young animals, respectively. Using this value, the contribution of soft feces to CP intake in adult nutrias was estimated as 16%, superior to that obtained in rabbits for a diet with similar ADF concentration. To Met and Lys intake the contribution of soft feces was 26% and 19%, respectively in adult animals. These results suggest that coprophagy is quite an effective manner for nutrias to ingest extra protein.
为了评估食粪行为对蛋白质摄入的贡献，我们观察了成年和幼年圈养海狸鼠的行为，特别是与食粪行为相关的行为（实验1），并分析了软粪、整个硬粪以及硬粪的黑色部分和绿色部分的化学成分和氨基酸组成，包括二氨基庚二酸（DAP），它是细菌来源蛋白质的一个指标（实验2）。成年海狸鼠每24小时进行48次食粪行为，幼年动物为28次，这种行为不仅有24小时的节律，还有1小时或2小时的短期节律。海狸鼠在日落后大量进食和饮水，随后从午夜到清晨进行食粪行为，然后在一天的大部分时间里躺下休息。当阻止食粪行为时，我们采集了从午夜到中午产生的软粪，其粗蛋白（CP）、以干物质（DM）计的DAP以及以16克氮计的13种氨基酸的浓度均高于硬粪（P<0.05），而酸性洗涤纤维（ADF）含量较低（P<0.05）。硬粪的黑色部分CP含量高于绿色部分（P<0.05），尽管ADF含量较低（P<0.05）。硬粪黑色部分的化学成分与软粪没有显著差异。实验1中成年和幼年动物每24小时排出的软粪干重分别为34.5克和9.7克DM。利用这个值，估计成年海狸鼠软粪对CP摄入的贡献为16%，高于ADF浓度相似的饮食条件下兔子的贡献。对于成年动物，软粪对蛋氨酸和赖氨酸摄入的贡献分别为26%和19%。这些结果表明，食粪行为是海狸鼠摄取额外蛋白质的一种非常有效的方式。
