Improving The Nutritive And Feeding Value Of Double-low Rapeseed Hull In Ruminants Diets

The content of neutral detergent fiber (NDF) in double-low rapeseed hull was assessed as deliberated index. In the experiments, the mixed nesting design was adopted to screen out the optimal treatment group and treatment time by three different chemical methods: dry NaOH method (the treated time spans were 1d, 2d, 3d, respectively) ; urea-ammonification treatment (the treated time spans were 10d, 15d, 20d, respectively); alkali-ammonification treatment(the treated time spans were 15d, 20d, 25d, respectively). L₉ (3⁴) orthogonal design was adopted to screen out the optimal treatment group, which was characterized by the optimal ratio of cellulose, β-glucanase, xylanase and a-amylase. Thus, the optimal chemical treatment and optimal enzyme preparation treatment were determined. Structure changes of optimal methods were analysed with scanning electron microscope (SEM). Meanwhile, the experiments studied the effects of the different diets, which were formulated with straw, untreated double-low rapeseed hull, double-low rapeseed hull treated with chemical method and double-low rapeseed hull treated with enzyme preparation as the roughages, respectively, on the growth performance of black goats from Hubei Macheng. The results were as follows:Compared with the control group (untreated group) , the contents of NDF in double-low rapeseed hull treated by dry NaOH method, urea-ammonification treatment and alkali-ammonification treatment all decreased; and the content of the degradability of NDF after 24h in rumen was enhanced. After the hull had been treated by different chemical methods, there was extremely significant difference in the content of NDF and in the degradability of NDF (P<0.01) . After the hull had been treated for different time spans by the same method, there was extremely significant difference in the content of NDF and in the degradability of NDF within the groups (P<0.01) . Compared with thecontrol, the degradability of NDF of double-low rapeseed hull treated by dry NaOH method increased by 74.22%, 66.16%, 58.64%, respectively; the degradability of NDF in the hull treated by urea-ammonification treatment increased by 63.81%, 19.07%, 15.64%, respectively; the degradability of NDF in the hull treated by alkali-ammonification treatment increased by 28.88%, 58.04%, 7.79%, respectively.There was no significant difference in the content of NDF or in the degradability of NDF between trial groups after double-low rapeseed hull had been treated by enzyme preparation (P>0.05). Compared with the control, the content of NDF of treated groups decreased by 8.15%, 6.59%, 8.56%, 9.81%, 8.42%, 9.57%, 7.11%, 7.62%, and 8.05%, respectively; the degradability of NDF of treated hull increased by 88.07%, 89.05%, 72.75%, 61.42%, 59.29%, 54.77%, 68.72%, 64.96%, and 90.74%, respectively.SEM experiment showed that the structure of the pre-and post-treated double-low rapeseed hull changed significantly. The structure of untreated double-low rapeseed hull was compact, and the cellular organelles were easily invisible. After alkali-ammonification treatment, the thin cell tissue expanded, and some "aperture" structures formed. Most cellular organelles disintegrated and dropped. The surface of double-low rapeseed hull treated by enzyme preparation was smooth. The "aperture" structures were more regular, and the cellular organelles disintegrated and dropped completely. This experiment showed that the cell wall became loose after the double-low rapeseed hull had been treated, which provided advantaged conditions for infiltration of rumen liquid, thus enhancing the efficiency of double-low rapeseed hull utilization.There was significant difference in feed intake, average daily gain (ADG) and Feed/Gain (F/G) of goats between the two treated group and the straw group (P< 0.05) . There was not significance in these aspects between the trial group and the untreated double-low rapeseed hull group (P>0.05 ); however, the feed intake and ADG of the goats increased, while F/G of the goats decreased.The above results suggested that the method of alkali-ammonification treatment for 20 days at normal temperature was optimal; the optimal ratio of enzyme preparation was cellulose, 0.3846g; fi-glucanase, 0.1667g; xylanase, 0.2000g; a-amylase, 0.0125g (500g double-low rapeseed) . Alkali-ammonification treatment and enzyme preparation treatment could enhance the nutritive value of double-low rapeseed hull, and the treateddouble-low rapeseed hull could promote the growth performance of goats.