| In order to illustratting the unkown mechanism of silkworm excrement, We carried out the research on the nutritional evaluation of silkworm excrement, the effects of the different ratios of silkworm excrement to rice straw on the rumen microbial fermentation in vitro, and the effects of diets with different concentrations of silkworm excrement on the growth, rumen microbial, and slaughter of sheep. And the results are showed as follows:Trial 1:Proximate analysis of silkworm excrement. The results showed as follows:1) The dry matter, rude protein, neutral detergent fiber, acid detergent fiber, curde fibre, ether extract, or-ganic matter, Ca, P respectively were 89.61%,16.85%,34.32%,17.64%,20.91%,3.95%, 79.60%,11.36%,0.44%.2) The dry matter, crude protein, neutral detergent fiber, acid deter-gent fiber effective degradation rate of silkworm excrement respectively were 47.30%,43.26%, 47.56%,36.17%.3) The metabolic energy and grading index value of silkworm excrement is 8.27 MJ/Kg and 3.38.Trial 2:In vitro fermentation was conducted to investigate associative effects of different mix-tures of silkworm excrement and rice straw. In the trail, SE and RS were mixed at the ratios of 100:0,80:20,60:40,40:60,20:80,0:100, respectively, the mixtures were incubated in vitro for 24 hour and 72 hour. The results showed as follows:1) The pH values varied between 6.26-6.73, being in the appropriate range.2) The NH3-N concentration of SE40 and SE60 groups was high-er than these of the others.3) The TVFA production of various groups increased with the in-creasing of SE:RS ratios, the ratio of acetate to propionate were SE80<SE40<SE60, there were no significant difference between them but significantly lower than the other groups (P>0.05).4) The SE80, SE40 and SE60 were significantly higher than the other groups in MCP production (P<0.05).5) The higher the SE:RS ratio was, the higher the degradability of in vitro organic matter was.6) The accumulated gas production of SE80 group was higher than these of the other groups (P<0.05).7) It is indicated that, the optimum group is the ratio of 80:20, based on its maximum associative effect (0.76) between the silkworm excrement and rice straw.Trial 3:This Experiment was conducted to evaluate the effects of different proportion silkworm excrement in diet on growth performance, nutrient digestibilities and metabolism, serum bio-chemical indexes and the change of rumial bacteria of sheep. Thirty-two lambs (24.06±2.25 Kg) were randomly divided into four groups with 8 replicates per group. Lambs in the groups were fed the corn based concentrate and rice straw diets and supplemented with 0 (control group), 20%(T20),30%(T30),40%(T40) silkworm excrement, respectively. The experiment lasted for 75 days, three lambs in each group were slaughtered to determine the change of rumial bacte-ria at end of the experiment. The results showed as follows:1) The average daily gain (ADG), dry matter intake (DMI), feed conversion ratio (F/G) in groups T20 and T30 were significantly higher than those in groupT40 (P<0.05). There was no significant difference on the ADG, F/G in groups T20, T30 and control group (P>0.05).2) There was no significant difference on the DM apparent digestibility and OM apparent digestibility in all groups (P>0.05). The CP apparent di-gestibility in group T20 was significantly higher than that in group T40 (P<0.05). The NDF ap-parent digestibility in group T30 was significantly higher than that in control group (P<0.05). The ADF apparent digestibility in group T30 and T40 were significantly higher than that in group T40 and control group (P<0.05).3) The GLO in control group was significantly lower than that in groups T20 and T40 (P<0.05). The ALP in groups T20, T30, and T40 was signifi-cantly higher than that in control group (P<0.05). The BUN in groups T30, T40 were signifi-cantly higher than that in control group (P<0.05). The TG in groups T20, T30, and T40 was sig-nificantly lower than that in control group (P<0.05). The HDL in groups T40 was significantly higher than that in control group (P<0.05). The LDL in groups T40 was significantly lower than that in control group (P<0.05), and there were no significant difference on HDL and LDL in groups T20, T30, T40 (P>0.05).4) The diet which increse SE 30%, promoted B. fibrisolovens, R. flavefaciens, P. ruminicola, R. amylophilus to significantly starch adhesive rumen microorgan-ism(P<0.05), improvemed the degradation rate of rice straw. Raising the concentration of vola-tile fatty acid and ammonia nitrogen significantly in ruminal environmental (P<0.05).Trial 4:This experiment was conducted to evaluate the effects of different proportion silkworm excrement in diet on slaughter performance, organ weight, meat physicochemical characteristics and nutritional ingredient. Three lambs in each group were slaughtered at end of the feeding ex-periment. The dressing percentage in groups T20 and T30 were significantly higher than that in group T40 (P<0.05), and there was no significant difference in control group (P>0.05); There were no significant difference on carcass weight among groups T20, T30 and T40 (P>0.05); The loin muscle area and GR value among groups T20, T30 and T40 were significantly higher than those in control group (P<0.05)3) The heart weight of T20 was significantly higher than that in control group (P<0.05), the spleen weight of T30, T20 was significantly higher than that in con-trol group (P<0.05).3) There were no significant difference on pH45min among groups T20, T30 and T40 (P>0.05), the pH24h of T30, T40 was significantly higher than that in control group and group T20 (P<0.05). The spleen weight of T30, T20 was significantly higher than that in control group (P<0.05). The shearing force of T20, T30, T40 was significantly lower than that in control group (P<0.05), and there were no no significant difference on shearing force in group T20, T30, T40 (P>0.05). There were no no significant difference on L*,a*, b* in all groups (P>0.05).4) There were no no significant difference on water content and ash content in all groups (P>0.05). The content crude protein of T20, T30, T40 was significantly higher than that in con-trol group and group T40 (P<0.05). The content intramuscular fat of T20, T30 was significantly higher than that in control group (P<0.05). |
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