Evaluation on Nutrient Degradation Rate and Combination Effects of Different Roughage Combinations of Donkey by in Vitro Pepsin-Trypsin-Cecal Fluid Method
In vitro three-step method(pepsin-trypsin-cecal fluid method)was used in this study,the in vitro nutrient degradation rate of gastro-intestinal-cecum(GICD)and the contribution rate of gastro-intestine nutrient degradation in different roughage combinations were compared.The fermentation parameters of cecum in vitro were determined by studying the residue after degradation through stomach and small intestine,to explore the combination effects of main roughage.It provides a basis for improving the scientific collocation and utilization efficiency of roughage resources in donkey production.Healthy adult Texas donkeys were selected as cecal fluid donors for culture in vitro.A single-factor completely randomized design was adopted,which was divided into 4 groups with 6 replicates per group.The millet straw was mixed with corn straw(millet straw∶corn straw=6∶4)as the control group(CON group).The other three groups(groups Ⅰ,Ⅱ and Ⅲ)used alfalfa,whole corn silage and Leymus chinensis to replace 20％of the millet straw and corn straw in CON group,respective-ly.The results showed that compared with the CON group,GICD and digestive energy(DE)of dry matter(DM)and organic matter(OM)in group Ⅱ and the GICD of crude protein(CP)in group I were significant-ly increased(P＜0.05).GICD of neutral detergent fiber in groups Ⅰ,Ⅱ,Ⅲ and the GICD of acid detergent fiber in groups Ⅰ and Ⅲ were significantly increased(P＜0.05).There was no significant difference in GICD of hemicellulose among all groups(P＞0.05).The in vitro degradation contribution rates of DM and OM in the stomach-small intestine(pre-cecum)and CP contribution rates in groups Ⅰ,Ⅱ and Ⅲ were significantly higher than those in CON group(P＜0.05).The results of cecum fermentation in vitro showed that there were no significant differences in pH and NH3-N concentration among all groups(P＞0.05).The concentration of bacterial protein and total volatile fatty acid in CON group was lower than that in other groups(P=0.091,P=0.075).At 3,24 and 48 h time points,the gas production in the CON group was lower than that in other 3 groups(P=0.061,P=0.096,P=0.080).At the rest of the time,there was no significant difference in gas production among all groups(P＞0.05).Multiple combined effect values(MFAEI)was groups Ⅱ,Ⅰ,Ⅲand CON group from high to low.In conclusion,substitution of alfalfa grass,whole corn silage and Leymus chinensis for 20％of millet straw and corn straw,respectively,produce positive combination effect,improve nutrient degradation rate and cecal fermentation function,especially the combination effect of whole corn silage and alfalfa replacement group is better.[Chinese Journal of Animal Nutrition,2024,36(5):3183-3191]
万方数据
维普
