| The purpose of this experiment was to evaluate the nutritional value of the black watermelon seed meal for fattening sheep by using nylon bag technique and in vitro three-step technique.To investigate the effects of levels black watermelon seed meal on ruminal microbial protein synthesis,whole tract digestibility,nitrogen(N)metabolism and production performance of fattening sheep.Experiment 1: The purpose of this experiment was to evaluate the effective degradability of watermelon seed by-products(watermelon seed shell,watermelon seed powder and watermelon seed meal)in rumen of fattening sheep.Three Kazakh sheep weighed(33±3.72)kg with permanent rumen cannulas were used as experimental animals.Using nylon bag technique to evaluate the effective degradability of the dry material(DM),organic material(OM)and crude protein(CP)of watermelon seed by-products in rumen.The results showed that,when the outflow rate(Kp)was 4.98 %/h,that the effective degradability of DM were 7.84%,16.09% and 19.25% of watermelon seed shell,watermelon powder and watermelon meal,the effective degradability of OM were 4.12%,14.64% and 17.71%,the effective degradability of CP were 12.62%,36.02% and 49.22%.And the feeding value of watermelon seed shell was poor,the effective degradability of CP in the watermelon seed powder and watermelon seed meal were higher,it can be used as a new source of protein supplement in fattening sheep.Experiment 2:In this experiment,3 healthy Kazakh sheep weighted(34±4.05)kg with permanent rumen cannulas were used as experimental animals.Using in vitro three-stage technique to evaluate the intestinal digestibility of the black watermelon seed by-products in fattening sheep.The results showed that,after degrading for 16 h in rumen,the degradation rates of DM,CP and OM of the black watermelon seed by-products were all presented as black watermelon seed meal>black watermelon seed powder>black watermelon seed shell(P<0.01),which was similar to the rule in experiment 1.After simulating intestinal digestion in vitro,the intestinal digestibility of DM,OM and CP of black watermelon seed shell were 15.81%? 17.88% and 14.34%.The intestinal digestibility of the protein components of the seed powder and seed meal respectively were 41.89% and 62.24%,and the intestinal digestibility of seed meal protein was 48.48% higher than that of seed powder(P<0.01).The results showed that the intestinal digestibility of the seed shell's nutritive components were very low in fattening sheep,its feeding value is poor.The protein components' intestinal digestibility of the seed powder and the seed meal were high.Moreover,the seed meal was a better protein supplement than the seed powder,and it can provide more RUP for fattening sheep for intestinal absorption and utilization.Experiment 3: Three healthy Kazakh sheep weighted(36±2.49)kg were selected as experimental animals.The trial was designed using a 3×3 Latin square experiment to investigate the effects of the addition of 0%,10% and 20% seed meal in TMR on ruminal microbial protein synthesis and conversion efficiency,whole tract digestibility and nitrogen(N)metabolism of fattening sheep.The results showed that the MCP conversion efficiency of each treatments were similar(P>0.05),with the addition of seed meal increasing,The synthesis of MCP increased first and then decreased,and there was no significant difference between TMR1 and TMR3(P>0.05),but they both were significantly lower than TMR2(P<0.01).The addition of seed meal into the rations had no significant effect on the N intake,intestine's total N and MN in the fattening sheep(P>0.05),the urine nitrogen output presented a decreasing law(P<0.05),the fecal nitrogen output of TMR2 was lower than that of TMR1 and TMR3(P<0.01),and the N deposition showed as TMR2>TMR3>TMR1(P<0.05).The whole tract digestibility of DM was similar with other groups(P>0.05).The whole tract digestibility of OM of TMR2 was significantly higher than that of TMR1 and TMR2(P<0.01).The highest whole tract digestibility of N in TMR2 was 72.03%,it was respectively 17.83% higher than TMR1(P<0.01)and 11.87% higher than TMR3(P<0.05).It can be seen that with adding seed meal into the rations,the MCP synthesis,the deposition and whole tract digestibility of N were increasing fattened sheep.However,due to the large horizontal gradient of the addition of seed meal in the experimental design,the optimal proportion of seed meal in the ration of fattening sheep cannot be indicated.Experiment 4:In order to determine the appropriate dosage of black watermelon seed meal in the total mixed rations of fattened sheep,25 Kazakh fattening sheep,which had similar age and weighted(23±3.18)kg,were used as experimental animals.Single and random factor design was adopted in the experiment,25 experimental sheep were divided into 5 groups,and every 5 sheep in each group were raised in a single sheepfold.We designed 5 TMRs,with the seed meal addition levels respectively of 0%,5%,10%,15% and 20%,to carry out the fattening experiment.The results showed that the ADG of test group 1 was 214.47 g/d,compared with test group 1,test group 2,3 and 4 respectively improved by 6.61%(P<0.05),10.26%(P<0.01)and 13.36%(P<0.01).However,there was no significant difference in ADG between test group 5 and test group 1(P>0.05).F/G showed a trend of decreasing first and then increasing among each treatment groups,and the inflection point occurred when the addition amount of seed meal over the 15%.The results showed the black watermelon seed meal was added into the total mixed rations of fattening sheep as a supplement source of protein,it had potential benefits on ruminal microbial protein synthesis,nitrogen deposition and effective effect of fattening in fattening sheep,and the supplementation of black watermelon seed meal in fattening sheep feeding is recommended that feeding at a level not exceeding 15% of the total intake. |
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