Seankamsorn Anuthida, Cherdthong Anusorn, Wanapat Metha
Tropical Feed Resources Research and Development Center (TROFREC), Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
Animals (Basel). 2019 Dec 23;10(1):37. doi: 10.3390/ani10010037.
It was hypothesized that the combination of glycerin and chitosan improves ruminal fermentation efficiency via an enhanced propionate (C3) and reduces in vitro CH production. This was explored through in vitro gas production with substrates containing crude glycerin, which replaced cassava chips in the studied ration. The experimental design was organized following a 3 × 3 factorial in completely randomized design and the arrangement of treatments were different levels of crude glycerin supplementations 0, 10.5, and 21% of total mixed ration (TMR) and chitosan levels were added at 0, 1, and 2% dry matter (DM) of substrate. Then, 0.5 g of TMR substrates were added into 40 mL bottles, together with respective doses of chitosan and then incubated at 39 °C. The dietary treatments were performed in three replicates within the incubation, and incubations were repeated on three separate days (runs). No interactions were found between crude glycerin and chitosan doses in terms of theoretical maximum of asymptotic gas production (), rate of gas production (), the discrete lag time prior to gas production (), or the cumulative gas production at 96 h of incubation ( > 0.05). Cumulative gas production at 96 h of incubation was similar among the doses of crude glycerin and levels of chitosan, which ranged from 64.27 to 69.66 mL/g DM basis of substrate ( > 0.05). The concentration of ruminal NH-N after 2 and 4 h of incubation ranged from 14.61 to 17.10 mg/dL and did not change with the addition of crude glycerin with chitosan ( > 0.05). The concentration of CH after 2 h of incubation did not change among treatments ( > 0.05), whereas after 4 h of incubation, CH synthesis was significantly reduced by enhancing doses of crude glycerin and chitosan ( < 0.05). The combination of 21% of crude glycerin in TMR with 2% chitosan depressed CH production as much as 53.67% when compared to the non-supplemented group. No significant crude glycerin and chitosan interaction effect was detected for in vitro digestibility of nutrients after incubation for 12 and 24 h using the in vitro gas production technique ( > 0.05). In addition, no significant changes ( > 0.05) were observed in total volatile fatty acids, acetate (C2) or butyrate content among treatments and between the main effects of crude glycerin with chitosan. At 4 h of incubation, ruminal C3 content and the C2 to C3 ratio changed significantly when crude glycerin and chitosan was added ( < 0.05). The 21% crude glycerin incorporate into TMR, in combination with 2% additional chitosan, increased C3 content by 26.41%, whereas the ratio of C2 to C3 was reduced by 31% when compared to the control group. Propionate concentration increased by 11.75% when increasing levels of chitosan at 2% of substrate, whereas the C2 to C3 ratio decreased by 13.99% compared to the 0% chitosan group. The inclusion of crude glycerin at 21% in TMR diets with chitosan supplementation at 2% enhanced ruminal propionate concentration and reduced methane production without causing any detrimental effect on the gas kinetics or nutrient digestibility.
据推测，甘油和壳聚糖的组合可通过提高丙酸（C3）来提高瘤胃发酵效率，并减少体外甲烷的产生。通过使用含有粗甘油的底物进行体外产气实验来探究这一推测，其中粗甘油替代了研究日粮中的木薯片。实验设计采用3×3析因完全随机设计，处理方式为粗甘油添加量分别为总混合日粮（TMR）的0、10.5%和21%，壳聚糖添加量分别为底物干物质（DM）的0、1%和2%。然后，将0.5 g TMR底物加入40 mL瓶中，再加入相应剂量的壳聚糖，然后在39℃下孵育。日粮处理在孵育过程中进行三次重复，且在三个不同的日子（批次）重复孵育。在理论最大渐近产气率（）、产气速率（）、产气前的离散滞后时间（）或孵育96小时时的累积产气率（>0.05）方面，未发现粗甘油和壳聚糖剂量之间存在相互作用。孵育96小时时的累积产气率在粗甘油剂量和壳聚糖水平之间相似，范围为每克底物干物质64.27至69.66 mL（>0.05）。孵育2小时和4小时后瘤胃NH-N浓度范围为14.61至17.10 mg/dL，且随着粗甘油与壳聚糖的添加未发生变化（>0.05）。孵育2小时后处理组之间CH浓度未发生变化（>0.05），而孵育4小时后，随着粗甘油和壳聚糖剂量的增加，CH合成显著降低（<0.05）。与未添加组相比，TMR中21%的粗甘油与2%的壳聚糖组合可使CH产生量降低多达53.67%。使用体外产气技术孵育12小时和24小时后，未检测到粗甘油和壳聚糖对营养物质体外消化率有显著的相互作用效应（>0.05）。此外，处理组之间以及粗甘油与壳聚糖主要效应之间的总挥发性脂肪酸、乙酸（C2）或丁酸含量未观察到显著变化（>0.05）。孵育4小时时，添加粗甘油和壳聚糖后瘤胃C3含量以及C2与C3的比值发生显著变化（<0.05）。与对照组相比，TMR中添加21%的粗甘油并额外添加2%的壳聚糖可使C3含量增加26.41%，而C2与C3的比值降低31%。当底物中壳聚糖水平增加到2%时，丙酸浓度增加了11.75%，而与0%壳聚糖组相比，C2与C3的比值降低了13.99%。TMR日粮中添加21%的粗甘油并补充2%的壳聚糖可提高瘤胃丙酸浓度并减少甲烷产生，且不会对气体动力学或营养物质消化率产生任何不利影响。
