Effect Of Betaine Levels On Blood Biochemical Parameters And Growth Performance Of Duroc-landrace-yorkshire Cross-bred Pigs In Fattening Period In Different Low Protein Diets

The purpose of this study was to investigate the effect of different dietary protein content and betaine content on blood biochemical parameters and growth performance of Duroc-Landrace-Yorkshire cross-bred fattening pigs.Research is analyzed from three main discussions,1)The effect of different protein levels in diets on fattening pigs;.2)The effect of different betaine levels in diets on fattening pigs;3)The effect of the interaction between proteins and betaine in diets on the fattening pigs.Randomly selected 150 Duroc-Landrace-Yorkshire cross-bred fattening pigs as test animals,those are about 3 months old,good healthy and in similar weight about 49 ± 4.04 kg.Those are randomly and averagely divided into 10 groups,which is 15-head fattening pigs each group.The first sets as the control group,and the remaining nine groups are test.The control group was fed with a controlled diet prepared by the NRC（2012）recommended standard（15% crude protein,no betaine）,In accordance with the two-factor test design,including 13%,14%,15% three protein levels and 0.1%,0.15% and 0.2% betaine levels,9 different trials diets were prepared to feed,the experimental groups were fed to the diet Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ,Ⅵ,Ⅷ,Ⅶ,and IX.Feeding for a period of 35 days,the initial and final weight will be tested and record at early and end of feding experiment,and daily feed intake will be record during the feeding experiment.Anticoagulant blood samples were collected from the vena cava anterior before and after feeding experiment,then plasma was separated respectively.Plasma biochemical parameters were measured by automatic biochemical analyzer and the results were statistically processed analyzed by SPSS23.0 software.The results of the study are as follows:1)The results that effects of different protein levels in diets on fattening pigs showed that protein levels in diets had significant or highly significant effects on TP,BUN,ALB,ChE,CK,α-HBDH,TC,LDL-C,HDL-C,Ca²⁺,and IP（P<0.05 or P<0.01）.Reducing the protein level in the diet,it can improve the fattening pig ADG,G/F,reduce F/G,improve the growth performance of fattening pigs,which 14% protein level is best in this test,ADG,F/G are improved,but ADFI rises obviously,may be at 14% protein level can stimulate fattening pigs to eat more.Reduce the protein level in the diet,it can reduce the BUN content and ALB content（P<0.05）,but the difference with the recommended standards is not significant（P>0.05）,at the same time,14% protein levels,TP content increased significantly,indicating that 14% protein levels can meet the nutritional needs of fattening pigs.Lower dietary protein levels,it has no effect on the content of IgG,but CK,ALP,α-HBDH activity significantly are decreased（P<0.05）,ChE activity is increased,indicating that low protein diet will not be immune to fattening pigs and heart,liver and other organs have adverse influence,but also it may improve fattening pig fat deposition.The content of TC,LDL-C and HDL-C are increased and later decreased with the protein level decreased in the diet,which was to increase the content of TC,LDL-C and HDL-C at 14% protein levels,indicating that low protein diets are beneficial to the metabolism and utilization of cholesterol in organism.Reduce the dietary protein level,it has no effect on the content of GLU（P>0.05）,but the Ca²⁺,IP are a significant reducted（P<0.05）.It is indicated that low protein diets will not affect the feeding of fattening pig blood sugar,but may affect the utilization of calcium and phosphorus in organism.In addition,CHE,CK,Ca²⁺,IP has decreased the protein content in the diet and showed the trend of secondary curves.2)The results that effect of different betaine levels on fattening pig in diets show that in 0.15%,0.2% betaine levels,it can improve fattening pig ADG,G/F,reduce F/G.Adding the amount of 0.15% which can improve the growth performance of fattening pigs is best,ADG,F/G,G/F are improved,ADFI reduced.The addition of betaine can increase TP content,but cannot get to the significant level（P>0.05）,the BUN content has decreased trend with the increase of betaine,and the betaine has no significant effect on ALB（P> 0.05）.Adding betaine can not significantly increase the IgG content（P>0.05）,but decrease ChE,CK,ALP,α--HBDH activity,indicating that adding betaine has the function of protecting myocardium and liver,and it also shows that betaine has the effect of promoting fat decomposition metabolism and decreasing fat deposition.The addition of betaine can improve the content of TC,LDL-C and HDL-C,and reduce TG content,which shows that betaine has the effect of regulating the proportion of endogenous lipoprotein,stimulating blood to accelerate the delivery of cholesterol and protecting liver.Adding betaine can significantly reduce the Ca²⁺,IP,Mg²⁺ content,that it may lead to decrease absorption of Ca²⁺,IP,Mg²⁺ in fattening pig.Adding betaine does not affect to the glucose supply in fattening pigs（P< 0.05）.3)The results that effect of the interaction between protein and betaine on the fattening pigs show that the interaction between protein content and betaine content in the diets has a highly significant effect on TP,BUN,IgG,ChE,CK,ALP,α-HBDH,TC,HDL-C,and GLU（P<0.01）in the plasma,has a significant effect on ALB and Ca²⁺（P<0.05）,and has no significant effect on TG and LDL-C（P>0.05）.Through the analysis of factors and multiple comparisons,and the control group as the reference,the various combinations are compared,14% protein +0.15% betaine combination is the best ratio in this test,which is beneficial to the growth performance of fattening pigs,and also reduces the feeding cost.