| To serve development of isoacids additive on increasing ruminant production and oxidation resistance with base data, this study was conducted to investigate the effects of isoacids on rumen fermentation in vitro and the performance and blood parameters of Nanjiang brown goat (NBG). Firstly, using vitro methods, we examined the effects of isoacids on rumen fermentation indexes, including gas production, pH, ammonia nitrogen (NH3-N), microbial protein (MCP) and volatile fatty acids (VFAs), to determine the most suitable ratio among four single isoacid and the most suitable volume of mix isoacids addition. And then, we used the suitable isoacids feeding NBG to investigate the effects of isoacids on performance and blood parameters of goats.Experiment1, to pick out the most suitable level of single isoacid on rumen fermentation in vitro, this study examined the effects of different levels of single isoacid on rumen fermentation parameters. The addition level of valerate,2-methy-butyrate and isobutyrate were0.0%,0.3%,0.6%,0.9%and1.2%of substrate dry matter (DM), and the addition level of isovaleric acid was0.0%,0.2%,0.5%,0.8%and1.1%of substrate DM, each level had four replicates. The results are as follows,There were no significantly differences in gas production and pH among different valerate addition levels (P>0.05). When valerate reached0.6%DM, compared with control group, MCP concentration increased significantly (P<0.05), NH3-N dropped significantly (P<0.05).0.2%DM isovalerate increased the gas production significantly (P<0.05), and there were no significant differences among the rest levels (P>0.05). The difference of pH was not significant among each level (P>0.05). Compared with control group,0.2%DM isovalerate dropped NH3-N concentration significantly (P<0.05). The MCP concentration of0.2%DM,0.5%DM and0.8%DM were significantly higher than control group and1.1%DM (P<0.05), thus, MCP peaked at0.2%DM.In different addition levels of2-methy-butyrate, gas production and MCP changed insignificantly (P>0.05). And at0.6%DM pH and NH3-N minimumed and were significantly lower than0.0%DM and0.3%DM (P<0.05).For gas production, there were no significant differences among addition levels of isobutyrate. pH of addition levels of isobutyrate were significantly lower than control group’s.0.9%DM’s MCP concentration was the peak and higher than control group’s and0.3%DM’s (P<0.05).In conclusion, use MCP as a standard to screen, the most appropriate level of single isoacid was that, valerate was0.6%DM, isovalerate acid was0.2%DM,2-methy-butyrate was0.6%DM and isobutyrate was0.9%DM.Experiment2, in this experiment, the orthogonal design of L9(34) was used. The results of experiment1was taken for reference, four single isoacid had3levels, respectively, valerate (0.3%DM,0.6%DM and0.9%DM), isovalerate (0.1%DM,0.2%DM and0.5%DM),2-methy-butyrate (0.3%DM,0.6%DM and0.9%DM) and isobutyrate (0.6%DM,0.9%DM and1.2%DM), and a control group added. The results were as follows, the gas production of treatment2and3were significantly rised than control group’s (P<0.05). pH of treatment2,3,4and6were significantly dropped (P<0.05), compared with treatment1,5,7,8and control group. NH3-N of treatment2was the lowest in all groups and significantly lower than control group (P<0.05). The treatment2’s MCP concentration was the highest in ten groups, significantly higher than treatment3,5,8,9and control group (P<0.05). For VFAs, treatment2’s TVFA and acetate concentration were the maximum among all the groups, acetate concentration was significantly greater than treatment5,8,9and control group (P<0.05), no significant difference with treatment1,3,4,6and7(P＞0.05). There was no significant difference in propionate and butyrate concentration among all the groups (P>0.05).All in all, gas production, NH3-N, MCP and VFAs were examined in vitro method, effect of treatment2on rumen fermentation in vitro was the best among all the groups. So the ratio of valerate, isovalerate,2-methy-butyrate and isobutyrate was6:2:3:9.Experiment3, after experiment2’s work, this experiment,6isoacids addition levels (0%DM,0.25%DM,0.5%DM,1.00%DM,2.00%DM and3.00%DM) were chosen for trial in vitro. And the results showed that, as the addition of mix isoacids rised, gas production increased at first, when isoacids reached1.0%DM the gas production peaked and then dropped, but there were no significant differences in all levels(P>0.05). pH dropped firstly, when addition level reached2.0%DM it rised, there were no significant difference among1.0%DM,2.0%DM and3.0%DM (P>0.05) and of which pH were lower than control group (P<0.05). At1.0%DM level, NH3-N and MCP level reached minimum and maximum respectively, and both of them had significant differences comparing with control group(P<0.05). For TVFA and acetate concentration also reached peak at1.0%DM and significantly higher than the rest groups. Propionate concentration of1.0%DM level was the highest and significant greater than0.25%DM,0.50%DM and control group (P<0.05). The butyrate of0.25%DM,1.00%DM and3.0%DM level were higher than control group (P<0.05), however, there were no significant differences among0.25%DM,1.0%DM,2.0%DM,3.0%DM (P>0.05).In conclusion, adding mix isoacids in culture solution may improve gas production, MCP and VFAs, decrease pH and NH3-N. In this test, the appropriate addition level of mix isoacids for rumen fermentation was1.0%DM.Experiment4, one factor randomized block design was taken,10goats equally separated in two groups, control group feeded basal feed, and isoacids group feeded isoacids and basal feed. After10d pre-test period,30-d test was carried out. The results showed that, compared with control group, average daily gain (ADG) increased20.17%(P<0.05), feed intake (FI) hardly affected (?>0.05) and feed conversion rised significantly (P<0.05). Urine nitrogen (UN) and total protein (TP) were significantly affected (P<0.05), dropped11.88%and rised4.30%, respectively. Triglyceride (TG), glucose (GLU), glutamic-pyruvic transaminase (GPT), glutamic-oxalacetic transaminease (GOT) were hardly affected (P>0.05).T4and growth hormone (GH) increased10.63%and11.85%(P<0.05), respectively. T3and Insulin (Ins) insignificantly increased (P>0.05). Essential amino acids (EAA) insignificantly increased (P>0.05). GSH-PX activity increased15.69%(P<0.05), SOD activity also rised but insignificantly (P>0.05). And MDA concentration dropped14.13%(P<0.05). In conlusion, isoacids added in feed may improve ADG, feed conversion and oxidation resistance of NBG... |
PDF Full Text Request