| In this experiment,the effects of compound chemical treatment of straw with two kinds of nitrogen sources on its fiber structure,production performance and urine physicochemical properties of Tan sheep were studied.The purpose of this paper was to study the effects of compound chemical treatment of straw with different nitrogen sources on its nutritional value and physical and chemical indexes of urine in Tan sheep.This experiment consists of two phases,the first stage wascomposite chemical treatment test:Composite chemical treatment trial design of three groups,respectively,the control group(unprocessed straw),trial group Ⅰ(4%urea+2%calcium oxide+1%sodium chloride compound chemical treatments of straw),trial group Ⅱ(7.1%ammonium chloride+2%calcium oxide+1%sodium chloride compound chemical treatments of straw).Then the surface structure and nutrient compositionbefore and after straw composite chemical treatment were measured.The second stage was feeding test.Twenty-four healthy three-month-old Ningxia Tan sheep with similar body weight were randomly divided into 3 groups with 8 sheep in each group.The ration of concentration to forage was 30:70,and the ratio of alfalfa to straw was 60:40 as roughage to feed Tan sheep,The control group was fed a basal diet+unprocessed straw,the trial group Ⅰ was fed a basal diet+straw compound chemical treated with urea,and the trial group Ⅱ was fed a basal diet+straw compound chemical treated with ammonium chloride.The preparation period was 15 d,and the formal experiment period was 60 d.After the end of formal experiment period,the growth performance,slaughter performance,meat quality,blood biochemical indexes,antioxidant capacity,digestion and metabolism,rumen fermentation parameters,urine physical and chemical indexes and kidney development of Tan sheep were measured.The results showed as follows:1)The fiber structure of straw was damaged by urea or ammonium chloride compound chemical treatment.Compared with the control group,the content of CP and Ca in rice straw in test Ⅰ group and test Ⅱ group was significantly increased(P<0.05),and the content of NDF was significantly decreased(P<0.05).The CP level of rice straw in Ⅱ group was significantly higher than that in test Ⅰ group(P<0.05),and the NDF content was significantly lower than that in test Ⅰ group(P<0.05).2)The apparent digestibility of NDF and ADF of Tan sheep in Ⅰgroup and Ⅱ group were significantly higher than those in control group(P<0.05).The nitrogen digestibility,nitrogen use efficiency and protein epigenetic value of Tan sheep in all test groups were significantly higher than those in control group(P<0.05).The DE and digestibility of GE of Tan sheep in Ⅰ group was significantly higher than that in control group and Ⅱ group(P<0.05),and the DE and digestibility of GE of Tan sheep in Ⅱ group was significantly higher than that in control group(P<0.05).On the 60th day of the experiment,the pH of rumen fluid in test group Ⅰ was significantly higher than that in control group(P<0.05).In the late period of the experiment,the rumen NH3-N content of Tan sheep in test Ⅰ group was significantly higher than that in control group(P<0.05);The acetic acid/propionic acid value of rumen fluid in test group Ⅰ and test group Ⅱ was significantly lower than that in control group(P<0.05).3)On day 30 of the experiment,the serum TP content of Tan sheep in Ⅰ group and Ⅱ group was significantly higher than that in the control group(P<0.05),the serum ALB content and HDL-C content of Tan sheep in Ⅱ group were significantly higher than that in the control group(P<0.05),and the serum Glu content of Tan sheep in test Ⅱ group was significantly lower than that in the control group on day 60.The content of UREA in Ⅱ group was significantly lower than that in Ⅰ group(P<0.05);On day 30 of the experiment,the activity of GSH-Px in serum of Tan sheep in Ⅰ group was significantly higher than that in control group(P<0.05),the activity of T-SOD in serum of Tan sheep in Ⅱ group was significantly higher than that in control group(P<0.05),and the content of MDA in serum of Tan sheep in Ⅱ group was significantly lower than that in control group(P<0.05)on day 60 of the experiment.4)The average daily gain(ADG)of Tan sheep in test Ⅰ group was significantly higher than that in control group and test Ⅱ group(P<0.05),the average daily gain(ADG)of Tan sheep in test Ⅱ group was significantly higher than that in control group(P<0.05),and the feed/gain(F/G)of Tan sheep in test Ⅰ group and test Ⅱ group was significantly lower than that in control group(P<0.05).The increase of chest circumference of Tan sheep in test Ⅰ group was significantly higher than that in control group(P<0.05),and the increase of body height of Tan sheep in test Ⅱ group was significantly higher than that in control group and test Ⅰ group(P<0.05).The economic benefit of the Ⅰ group was the highest,the test Ⅱ group was the second,and the control group was the lowest.The bone weight of Tan sheep in test Ⅰ group was significantly higher than that in control group and test Ⅱ group(P<0.05),and the eye muscle area of Tan sheep in test Ⅱ group was significantly higher than that in control group(P<0.05).The pH value of mutton of Tan sheep in test Ⅱ group was significantly higher than that in control group(P<0.05),the yellowness value B*was significantly lower than that in control group(P<0.05),and the brightness value L*was significantly lower than that in control group and test Ⅰ group(P<0.05).The content of mutton CP in test group Ⅰ and test group Ⅱ was significantly higher than that in control group(P<0.05),and the Ash in test group Ⅰ was significantly higher than that in control group and test group Ⅱ(P<0.05).5)The urine pH value of Tan sheep in test Ⅱ group was significantly decreased(P<0.05),and the magnesium content of Tan sheep in test Ⅱ group was significantly increased(P<0.05)compared with that in control group and test Igroup.The mucus in the renal tubules increased in the control group and the test group Ⅰ,while the renal capsule in the test group Ⅰ increased and the glomerulus shrank,The renal coefficient of test group Ⅱ was significantly higher than that of control group and test group Ⅰ(P<0.05).In conclusion,urea or ammonium chloride compound chemical treatment of rice straw can improve the nutritional value,and destroy the surface structure of rice straw.Urea or ammonium chloride compound chemical treatment of rice straw can promote the growth and development of Tan sheep,improve economic benefits,improve mutton quality,but also can improve the antioxidant capacity,promote the metabolism of nutrients,nitrogen and energy.In addition,ammonium chloride can also reduce the risk of urinary stones in Tan sheep. |
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