Chen Panliang, Li Yan, Shen Yizhao, Cao Yufeng, Li Qiufeng, Wang Meimei, Liu Mingchao, Wang Zhiyuan, Huo Zihan, Ren Shuai, Gao Yanxia, Li Jianguo
College of Animal Science and Technology, Hebei Agricultural University, Baoding 071001, China.
Key Laboratory of Healthy Breeding in Dairy Cattle (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Hebei Agricultural University, Baoding 071001, China.
Animals (Basel). 2022 Sep 30;12(19):2633. doi: 10.3390/ani12192633.
The objective of this study was to investigate the effects of dietary rumen-degradable starch (RDS, g/kg of DM) to rumen-degradable protein (RDP, g/kg of DM) ratios (SPR) on in vitro rumen fermentation characteristics and microbial protein synthesis (MCPS). Treatments were eight diets with SPR of 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 and 2.6 and were formulated to be isoenergetic, isonitrogenous, and isostarch. Substrates were anaerobically incubated in sealed culture vials (100 mL) for 6, 24 or 48 h. Three incubation runs were conducted within two consecutive weeks. With the increase of the dietary SPR, the gas production (GP), in vitro dry matter disappearance (IVDMD) and concentration of MCPS and total volatile fatty acids (TVFA) linearly increased after 6 h of incubation (p ≤ 0.01), whereas they quadratically increased and peaked at the SPR of 2.3 after 24 and 48 h of incubation (p < 0.05). In response to dietary SPR increasing, the in vitro neutral detergent fiber disappearance (IVNDFD) quadratically increased (p < 0.01), and the ammonia nitrogen (NH3-N) concentration linearly decreased (p < 0.01) after 6, 24 and 48 h of incubation. Based on the presented results, an SPR of 2.3 is recommended for formulating a diet due to its greatest IVDMD, IVNDFD, GP, TVFA and MCPS. However, as the results obtained are strictly dependent on the in vitro conditions, further in vivo studies are needed to verify our findings.
本研究的目的是探讨日粮瘤胃可降解淀粉（RDS，g/kg干物质）与瘤胃可降解蛋白质（RDP，g/kg干物质）比值（SPR）对体外瘤胃发酵特性和微生物蛋白质合成（MCPS）的影响。试验处理为8种日粮，其SPR分别为1.9、2.0、2.1、2.2、2.3、2.4、2.5和2.6，日粮配方为等能量、等氮和等淀粉。底物在密封培养瓶（100 mL）中进行厌氧培养6、24或48小时。在连续两周内进行了3次培养试验。随着日粮SPR的增加，培养6小时后，产气量（GP）、体外干物质消失率（IVDMD）、MCPS浓度和总挥发性脂肪酸（TVFA）呈线性增加（p≤0.01），而培养24和48小时后，它们呈二次曲线增加，并在SPR为2.3时达到峰值（p<0.05）。随着日粮SPR的增加，培养6、24和48小时后，体外中性洗涤纤维消失率（IVNDFD）呈二次曲线增加（p<0.01），氨氮（NH3-N）浓度呈线性下降（p<0.01）。基于上述结果，由于其具有最大的IVDMD、IVNDFD、GP、TVFA和MCPS，建议日粮配方的SPR为2.3。然而，由于所获得的结果严格依赖于体外条件，因此需要进一步的体内研究来验证我们的发现。
