| Ensuring the healthy state of weaning piglets and making them grow efficiently is the key to obtain good efficiency of pig production.However,the problem of poorer intestinal health and lower growth efficiency of piglets under the condition of feed without antibiotic has not been completely resolved.Under the condition of feed without antibiotic,the increase of intestinal microorganism may lead to the increase of amino acid requirement;and the disorder of intestinal flora.Therefore,the combination of plant extracts,such as carvacrol and thymol,can improve the intestinal health and growth performance of piglets.On the other hand,the development of gastrointestinal digestive system is not perfect when piglets are weaned.Using short-term protein restriction and then recovering nutrition supply to achieve compensatory growth,combined use of medium chain fatty acids and organic acids with synergistic antibacterial effect may also be an important way to improve the intestinal health of piglets and ensure the growth performance of piglets.Therefore,in order to explore the nutritional regulation measures to improve the intestinal health and growth performance of weaned piglets under the condition of feed without antibiotic,this experiment studied the joint regulation of dietary amino acid levels and compound plant extract components on the growth performance and intestinal health of weaned piglets.And the effect of restoring nutrient supply after short-term restriction of dietary protein level on diarrhea and growth performance of weaned piglets,and explored the effect of combined application of medium-chain fatty acid compound organic acid.This experiment is divided into two parts:Part I The effects of different levels of amino acid and compound plant extract components on the growth performance and intestinal health of weaned pigletsIn this experiment,560 weaned piglets(DLY)weighing 7.74±1.23 kg were selected for this experiment.They were randomly divided into 4 experimental groups according to the principle of relatively consistent body weight and sex,with 5 repeats in each group,each pen 28 piglets.A 2×2 experimental design was used,with 2 amino acid levels and 2carvacrol–thymol blend(CB)levels.Low level amino acid diet: earlier SID Lys level is1.35%,later SID Lys level was 1.25%;high level amino acid diet: earlier SID Lys level was 1.5%,and later SID Lys level was 1.4 %;the two amino acid level diets were not added or added with 500 mg/kg CB to form 4 test groups.The adaptation period was 7days,and the formal period was 42 days.On the 7,14,and 42 days after the start of the formal experiment,two piglets with a weight close to the average weight were selected in each pen to collect blood and fecal samples.The main results were as follows:1.Effects on growth performance and diarrhea: increasing the dietary amino acid level significantly reduced the ADFI(P < 0.05)and FCR(P < 0.01)of the piglets during0-14 days after weaning,and diarrhea rate(P < 0.05)of 0～14 days and 0～42 days after weaning;Dietary supplementation CB significantly increased the BW(P < 0.01),ADG,ADFI and ADLys I(P < 0.05)of piglets,and did not affect FCR,but there was a trend to reduce the diarrhea rate of piglets from 0～ 14 days after weaning(P < 0.1).2.Effect on plasma urea nitrogen: the influence of amino acid level and CB on PUN content had an interactive effect(P < 0.01).Increasing dietary amino acid levels significantly reduced the PUN content at 7 day after weaning(P < 0.01);Dietary supplementation CB significantly reduced the PUN content at 14 day after weaning(P <0.05).3.Effects on the oxidative stress state: dietary supplementation of CB significantly increased the plasma SOD level at 7 day and the plasma GSH-px level at 14 day after weaning(P < 0.05),significantly reduced the content of plasma MDA at 7 and 14 days.4.Effects on intestinal inflammatory response: increasing dietary amino acid levels significantly reduced the content of plasma IL-6(P < 0.01)and fecal lipocalcin 2 at 14 day after weaning(P < 0.05).Dietary supplementation of CB significantly reduced the content of fecal lipocalcin 2 at 7 day after weaning and plasma IL-1β at 14 day after weaning(P < 0.05).5.Effects on intestinal barrier function: the level of amino acid and CB had an interactive effect on the content of D-lactic acid and endotoxin in piglets’ plasma(P <0.05).Increasing dietary amino acid levels had a tendency to reduce the content of plasma D-lactic acid in piglets at 14 day after weaning,and increase the content of fecal secretory Ig A and MUC2 at 7 day after weaning(P < 0.1);Dietary supplementation of CB significantly reduced the content of plasma endotoxin in piglets at 7 and 14 days after weaning,as well as the content of plasma D-lactic acid at 7 day after weaning(P < 0.05),had a tendency to increase the content of fecal secretory Ig A in piglets 14 day after weaning(P < 0.1).6.Effects on specific fecal microorganisms and metabolites: increasing dietary amino acid levels significantly increased the relative abundance of Enterococcus and Lactobacillus in piglet feces 14 days after weaning(P < 0.05),and increased fecal isovaleric acid and the trend of total BCFAs content(P < 0.1);dietary supplementation of CB significantly reduced the relative abundance of fecal E.coli at 14 days after weaning(P < 0.05).Part II: Effects of medium-chain fatty acid compound organic acids on growth performance and intestinal health of weaned piglets under the conditions of compensatory growthIn this experiment,324 weaned piglets(DLY)weighing 6.77±1.10 kg at the age of21 days were selected and randomly divided into 3 groups according to the principle of relatively consistent body weight and sex.Each group has 6 pens,each pen 18 piglets.The dietary protein level of the piglets in the control group was 18% during the experiment period;the piglets of the compensatory growth group were fed a diet with a protein level of 16% on the 0-14 days of the experiment,and a diet with a protein level of18% on the 15-35 days of the experiment;the piglets in the compensatory growth combined with acid group were added with 6700 mg/kg coated medium-chain fatty acid compound organic acid on the basis of the compensatory growth group.The adaptation period was 7 days,and the formal period was 35 days.On the 14 th and 35 th days after the start of the formal experiment,two piglets with a weight close to the average weight were selected for each pen to collect blood samples.The main results were as follows:1.Effects on growth performance: compared with the control group,the BW and ADG of the piglets in the compensatory growth group and the compensatory growth +acid group were significantly reduced,and the FCR was significantly increased(P < 0.05).In the nutritional recovery stage,there was no significant difference in growth performance between the three groups.During the whole experiment,compared with the control group,the ADG of the piglets in the compensatory growth group was significantly reduced(P < 0.05),while the ADG of the piglets in the compensatory growth + acid group did not change significantly,but the FCR of the piglets in the two experimental groups increased significantly(P < 0.05).2.Effects on the content of plasma urea nitrogen: compared with the control group,the content of plasma PUN of piglets in the compensatory growth group was significantly reduced at 14 day after weaning,and the content of plasma PUN of piglets in the compensatory growth + acid group was significantly reduced at 35 day after weaning(P <0.05);Compared with compensatory growth group,the content of plasma PUN of piglets in the compensatory growth + acid group was significantly lower at 35 day after weaning(P < 0.05)3.Effects on the content of plasma hormone: compared with the control group,the levels of plasma growth hormone,insulin,IGF-1 and glucagon in the piglets of the compensatory growth group and the compensatory growth + acid group were significantly increased at 14 day after weaning.(P < 0.05).Compared with the control group,the levels of plasma IGF-1 of piglets at 35 day after weaning and plasma leptin levels of piglets at14 day after weaning in the compensatory growth group had an tendency to increase(P <0.1),while the compensatory growth + acid group were significantly increased(P < 0.05).In summary,the main conclusions of this study are as follows:(1)In the case of piglets with low overall diarrhea,the dietary SID Lys level within 2weeks after weaning is 1.5%,while ensuring the balance of other essential amino acids can improve the growth efficiency of piglets in the 2 weeks after weaning,however,the restore of nutrient supply after short-term restriction of protein intake do not achieve the effect of maintaining growth performance during the 35 d nursery period.(2)The improvement of diet amino acid level and the addition of carvol-thymol in diet mainly improve the metabolism of amino acids and the ability of intestinal antioxidation,and improve the growth performance of piglets in an antibiotic-free diet. |
PDF Full Text Request