| Small peptides generally refer to oligopeptides composed of 2-3 amino acids,also known as small molecule active peptides,which have the characteristics of fast absorption,low energy consumption and low carrier saturation,and can be 100%absorbed and utilized by the body.Studies have shown that small peptides can regulate animal intestinal microccological balance and have a positive impact on animal body development The purpose of this study was to investigate the effects of small peptides on growth performance and serum antibody level of pigs,and to provide theoretical basis for the application of small peptides in commercial pig feeding and management.One hundred 29-day-old piglets with an average body weight of about 10 kg were randomly divided into 5 treatment groups(control group,experimental groups 1,2,3 and 4)with 2 replicates in each group and 10 piglets in each replicate for 150 days.Pigs in control group were fed a normal pig diet,and pigs in experimental groups 1 were fed with 0.5%small peptide,experimental groups 2 with 1%small peptide,experimental groups 3 with 1.5%small peptide,and experimental groups 4 with 2%small peptide.Days 1 to 10 were pre-feeding period,and all pigs were fed normal diet.From day 11 to 31,the experimental group added small peptide as kyobo peptide;From day 32 to 150,small peptides were added as conservation peptides.Pigs were inoculated with blue ear vaccine,swine fever vaccine,foot-and-mouth disease type O vaccine,ring vaccine,pseudorabies vaccine and foot-and-mouth disease type O vaccine at the ages of 50,65,70,80,90 and 100 days,respectively.The pigs were weighed at the ages of 60,80 and 180 days.Serum samples were collected from two pigs in each replicate at 170 days of age,and feed intake and diarrhea were recorded during the experiment.Diarrhea rate,average daily gain and feed to meat ratio of pigs in each group were calculated,and serum levels of swine fever antibody,pseudorabies antibody and foot-and-mouth disease antibody,humoral immune indexes and interleukin levels were detected.The test results are as follows:1.Effects of adding Kyobo peptide on diarrhea and growth and development of piglets aged 40-60 daysThe diarrhea rate was 20%in control group,10%in test group 1,0%in test group 2,0%in test group 3,and 0%in test group 4.Overall,the diarrhea rate of the pigs fed with kyobutide was 2.5%,lower than that of the control group(17.5%).In addition,the average daily gain of the control group was 492.5g and the feed to meat ratio was 1.52.The average daily gain and feed to meat ratio of test group 1 were 523.5 g and 1.43 respectively.The average daily gain of test group 2 was 540 g and the feed to meat ratio was 1.40.The average daily gain of test group 3 was 541 g and the feed to meat ratio was 1.41.The average daily gain of test group 4 was 530 g and the feed to meat ratio was 1.43.2.Effects,of fattening peptides on growth performance of finishing pigs aged 61-180 daysThe average daily gain and feed to meat ratio of pigs in control group aged 61-180 days were 748.93 g and 2.62,respectively.After fattening peptide was added,the average daily gain and feed to meat ratio of test group 1 were 775.57g and 2.53 respectively.The average daily gain of test group 2 was 808.93 g and the feed to meat ratio was 2.42.The average daily gain of test group 3 was 812.71 g and the feed to meat ratio was 2.42,The average daily gain of test group 4 was 803.21g and the feed to meat ratio was 2.44.3.Effects of small peptide supplementation on serum antibody levels of pigs aged 41-180 daysThe serum antibody levels.of pigs at 170 days of age were detected.The serum antibody levels of pigs in control group were 35%swine fever antibody,38.3%PSEUDorabies gB antibody and 25.8%type O foot-and-mouth disease antibody.In test group 1,the antibody levels of CSF,gB and FMD were 37.5%,50%and 50%respectively.In test group 2,the antibody levels of classical swine fever,PSEUDorabies gB and FOOT-and-mouth disease were 83.2%,85%and 85%respectively.In test group 3,the levels of CSF antibody,PSEUDorabies gE antibody,gB antibody and FOOT-and-mouth disease antibody in experimental groups were 56.25%,75.5%and 60%respectively.In test group 4,the levels of CSF antibody,PSEUDorabies gB antibody and FOOT-and-mouth disease O antibody were 42%,50%and 56%respectively.4.Effects of supplementation of Kyobo peptide and fattening peptide on humoral immunity indexes of pigs aged 40-180 daysThe contents of total protein,albumin,IgA,IgG and IgM in experimental group were higher than those in control group.The contents of total protein,albumin,IgA,IgG and IgM of 1%fattening peptide were significantly higher than those of other experimental groups.5.Effects of dietary peptides and fattening peptides on interleukin levels in pigs aged 40-180 daysThe contents of IL-2,IL-4 and IL-5 in experimental group were significantly higher than those in control group.Compared with other experimental groups,the contents of IL-2 and IL-4 increased significantly with 1%fattening peptide,while the contents of IL-5 increased but not significantly.In conclusion,compared with the control group,dietary supplementation of small peptides in experimental groups can reduce diarrhea rate,increase average daily gain,decrease feed to meat ratio,and improve immune regulation ability of piglets.In addition,compared with experimental groups,experimental groups 2 and 3 can play a better role than experimental groups 1 and 4.At the same time,considering the production cost,1%small peptide dosage is the optimal dosage. |
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