Study On Silage Of Pomelo Peel Residue And Its Feeding Effect On Goats

China is rich in pomelo resources,after processing pomelo products,a large amount of pomelo peel residue waste is produced,which causes resource waste and environmental pollution.The pomelo peel residue is rich in nutrients and active substances,which have feeding values.However,because of its high moisture content and bitter substances,fresh pomelo peel residue has poor palatability when fed directly to animals.Therefore,pomelo peel residue was processed into silage in this study.This practice not only improve its nutritional value,but also solve problems including poor palatability and inappropriate storage,which is conducive to the rational utilization of waste resources,reduction in feed costs,and promotion in the high-quality development of modern animal husbandry.The purpose of this study was to screen the optimal scheme of pomelo peel residue mixed silage and to explore its feeding effect in goats by studying the effects of different water content and additives on the quality and nutritional components of pomelo peel residue.Therefore,pomelo peel residue mixed silage tests and goat feeding tests were carried out,and the results are as follows:1.Mixed silage tests:The orthogonal test of five factors and four levels L₁₆（4⁵）was designed to include different moisture content（65%,70%,75%,80%）,urea（0,1%,2%,3%）,EM bactericide（0,2.5,5,7.5 m L/kg）,pectin enzyme（0,0.25,0.5,1 m L/kg）and dry material type（no addition control,hybrid pennisetum hay,dried straw,bamboo powder）,and the fermentation quality and nutrient composition were determined for the above pomelo peel residue silages.The results showed that 13 of the16 treatment groups had the best comprehensive score of fermentation quality,of which adding dry materials had the greatest effect on the fermentation quality of pomelo peel residue silage with the order of effect as dry material species>urea>moisture content>EM inoculants>pectinase.The tests that were beneficial to improving the fermentation quality included the dry material types of no addition and bamboo powder,the urea levels of 0 and 2%,EM inoculant addition at 2.5 m L/kg and 5 m L/kg,pectinase additoin at 0 and 0.25 m L/kg and the silage moisture content of 70%and 65%.The results of the analysis of nutrient composition showed that:（1）urea had the greatesteffect on the crude protein content of pomelo peel residue silage,followed by neutral detergent fiber and acid detergent fiber,and the best two adding levels of urea were 3%and 2%;（2）no different effects were detected between dry material types on neutral detergent fiber and acid detergent fiber although the no addition group had the best effect;and（3）water content,EM inoculants and pectinase had little effect.Based on the analysis of fermentation quality,nutritional composition and cost saving,the optimal silage condition of pomelo peel residue included 70%moisture,adding 2%urea,2.5 m L/kg EM inoculants and additon of bamboo powder.2.Goat feeding tests:27-day-old Dazu black goats（female）at fattening stage with body weight of 19.84±0.83 kg were random Ly divided into 3 groups and fed with pomelo peel residue silage of the optimal scheme instead of sweet sorghum silage at three alternative levels of 0%（control group）,50%（trial group I）and 100%（trial group II）,to study the effects of pomelo peel residue silage on growth performance,nutrient apparent digestibility and blood biochemical indices of fattening sheep.Compared with the control group,the average daily feed intake of trial I and trial II groups were respectively increased by 16.97%（P<0.01）and 10.4%（P<0.05）.The average daily gain of trial group II was increased by 10.85%compared with control group（P<0.05）and 12.14%compared with trial group I（P<0.05）,but there was no significant difference between trial group I and control group（P>0.05）.The ratio of feed to gain（F/G）of trial group I was significantly higher than that of control group（P<0.05）,but there was no significant difference between trial group II and control group（P>0.05）.As for the apparent digestibility of nutrients of fattening sheep,compared with the control group,the apparent digestibility of CP in trial group II was increased by 6.61%（P<0.05）.The apparent digestibility of NDF in control group,trial group I and trial group II were 36.08%,42.79%and 53.47%,respectively,which obviously increased and there were significant differences among the three groups（P<0.05）.The apparent digestibility of ADF in the three groups were 18.36%,26.31%and44.20%,respectively,which also obviously increased and there were significant differences among the three groups（P<0.05）.The apparent digestibility of crude Ash in the three groups were 14.21%,31.6%and 42.83%,respectively,which were also significantly increased,and there were very significant differences among the three groups（P<0.01）.The apparent digestibility of ether extract tended to increase with the replacement amount of pomelo peel silage,but did not reach a significant level among the three groups（P>0.05）.As for the effects of blood biochemical indices of fattening sheep,compared with the control group,the contents of total protein and globulin in trial groups I and II were significantly increased,while the contents of urea nitrogen and blood glucose were significantly decreased（P<0.05）,and the contents of urea nitrogen and blood glucose were significantly decreased（P<0.05）,and trial group II showed better effect;There were no significant effect on the content of cholesterol and triglyceride（P>0.05）.Comprehensive analysis found that trial group II（50%replacement group）and trial group II（100%replacement group）had better feeding effect than control group on fattening sheep,and trial group II was better.In conclusion,mixed silage of pomelo peel resudue and bamboo powder is beneficial to improving the fermentation quality and nutritional value of pomelo peel residue,and had better feeding effect than that of sweet sorghum silage.The silage with pomelo peel residue was 100%instead of goat and showed better growth performance,improved nutrient apparent digestibility and blood biochemical indices.The results suggest that pomelo peel residue not only realizes purpose of feed utilization and reduction in environmental pollution,but also helps to reduce the cost of raising goats and promote the healthy development of local herbivorous animal husbandry.