Effects Of Dietary Protein Levels And Carbohydrate Source On Growth Performance And Gut Health In Weaned Piglets

The energy supply pattern of dietary energy substances is inevitably related to pig production and nitrogen deposition performance.The timely energy supply of glucose in the diet can reduce the portion of amino acids used for oxidative energy supply in the digestive tract,thereby improving protein utilization and reducing the production of protein metabolites.This has important theoretical significance for promoting a low protein diet.This study focuses on weaned piglets and explores the effects of different protein levels and carbohydrate sources on their growth performance,diarrhea,serum biochemical indicators,serum immune indicators,and intestinal health under the condition of consistent energy levels.This provides a reference for improving the growth performance,intestinal health,and reducing diarrhea rate of weaned piglets.72 25 day old weaned piglets with an initial weight of 7.2 ± 0.2kg were randomly divided into 4 treatment groups based on litter size,gender,and body weight.Each group had 6 replicates,with 3 pigs per replicate.The experiment is divided into two stages:the first stage is 1-14 days with a net energy of 2450kcal/kg,and the second stage is 15-28 days with a net energy of 2450kcal/kg.Group A1 of the first stage experiment:crude protein(CP)21.8%,corn starch 10.6%,;A2 group:CP 18.5%,corn starch 10.6%;B1 group:CP 21.8%,sucrose 4%,glucose 2%;Group B2:CP 18.5%,sucrose 4%,glucose 2%.Group A1 of the second stage experiment:CP 21.2%,corn starch 7%;A2 group:CP 17.9%,corn starch 7%;B1 group:CP 21.2%,sucrose 4%,glucose 2%;Group B2:CP 17.9%,sucrose 4%,glucose 2%.The experimental period is 28 days.Record daily food intake and score feces.After the feeding experiment,4 animals were randomly selected from each group,with a total of 16 animals undergoing slaughter experiments.Samples of serum and intestinal contents were collected for relevant indicator measurements.The main results of the experiment are as follows:1.The effect of dietary protein levels and carbohydrate source on the growth performance and diarrhea of weaned piglets:In the first stage of the experiment,there was no effect on the growth performance of weaned piglets.In the second stage of the experiment,the feed conversion rate of the sugar group was significantly higher than that of the starch group in terms of carbohydrate source(P<0.05),and there was an interactive effect;There was no difference in production performance at the carbohydrate source and protein level throughout the experiment,but there was an interaction in feed conversion rate(P<0.05).Adding glucose and sucrose to the diet of weaned piglets resulted in a significantly higher feed conversion rate than adding corn starch.In terms of fecal score and diarrhea rate,the high protein group was significantly higher than the low protein group(P<0.05);There is no significant difference in carbohydrate source.The low protein group can effectively improve diarrhea in weaned piglets.2.Effect on serum biochemical indicators:Adding different protein levels and carbohydrates with different sources to the diet does not affect the content of total serum protein and albumin.Corn starch can effectively reduce the concentration of triglycerides in the blood(P<0.05).Reducing protein levels can increase serum IgG content(P<0.05),while the IgA content in the corn starch group is significantly higher than that in the sugar group(P<0.05).Reducing protein levels and adding corn starch can effectively improve the immune performance of weaned piglets.3.Effects on the morphology and physical barrier of intestinal tissue:At the protein level,reducing the protein level can effectively increase the length of small intestinal villi(P<0.05),increase the velvet to hide ratio(P<0.05),and significantly increase the expression of small intestinal tight junction proteins ZO-1,Occludin,and Claudin(P<0.05)in weaned piglets,thereby improving the morphology and source of the small intestine;At the carbohydrate level,adding glucose and sucrose can effectively improve the length of j ejunal villi(P<0.05).The low protein diet and the addition of glucose and sucrose can effectively improve the intestinal tissue morphology and physical barrier function of weaned piglets.4.At the protein level,a low protein diet can increase the content of lactobacilli in the intestines of weaned piglets(P<0.05),while a high protein diet can increase the diversity of gut microbiota(P<0.05);In terms of carbohydrate source,adding corn starch can significantly increase the content of lactobacilli in the intestine of weaned piglets(P<0.05),improving intestinal health.Reducing the protein content in the diet and adding starch to the diet can effectively improve the gut microbiota.In summary,the addition of corn starch has a tendency to improve feed conversion rate,improve piglet immune performance and improve intestinal flora.Reducing dietary protein levels can effectively improve diarrhea in weaned piglets,improve immune performance,improve intestinal tissue morphology and physical barrier function,and improve intestinal bacteria.