The experiment was conducted to study the effects of the addition of encapsulated and nonencapsulated compound acidifiers in a diet based on maize-soyabean meal-extruded soyabean on gastrointestinal pH, growth performance, villus height and crypt depth of jejunum, intestinal digestive enzymes activities, microbial population and intestinal mucosal secretory immunoglobulin A in weaning piglets. Sixty-four 28-day-old, crossbred piglets (LandracexLarge White), weighing an average of 7.00±0.10 kg, were randomly assigned to four treatments with four replicates and four piglets (2 male and 2 female) per pen, according to single-factor design principle. The feeding trial lasted 35 days. The results showed that encapsulated compound acidifiers significantly reduced the gastrointestinal pH (P<0.01), and improved the average daily gain and the feed conversion ratio (P<0.05), but they had no significant effect on the average daily feed intake. In addition, encapsulated compound acidifiers significantly increased the ratio between the villus height and crypt depth of jejunum (P<0.01), and stimulated the sucrase activity and lactase activity (P<0.05) as well; during the later weaning period, encapsulated compound acidifiers significantly increased the counts of Lactobacillus and decreased the counts of Escherichia coli in the caecum and the colon (P<0.01); it was also noted that there was an insignificant tendency of lower secretion of intestinal mucosal secretory IgA (P>0.05). These results indicate that the encapsulated compound acidifiers improve the intestinal morphology and function by reducing the gastrointestinal pH, so as to enhance the intestinal adaptation and immunity, and consequently improve the growth performance of weaning piglets.

An experiment was conducted to study the effects of Tremella fuciformis ferment substance (TFS) supplementation in diets on the growth performance, fat deposition, blood lipids, and mRNA expression of lipid storage-related enzymes in the liver and adipose tissue of finishing pigs. Twenty eight-week-old pigs (10.03±0.59 kg) were randomly allocated to two dietary treatments: maizesoyabean meal-based diets with (TFS group) and without TFS (control group). The results of the experiment indicate that compared with the control group, the TFS diet led to a significant increase in the average daily gain and feed conversion ratio of pigs weighing 10 to 100 kg. However, the average backfat depth and leaf lard weight were not affected by TFS. Ingestion of TFS specifically decreased the serum triglyceride and glucose concentrations, but did not change the levels of total cholesterol and free fatty acids in the serum. The mRNA expressions of fatty acid synthase (FAS) and acetyl CoA carboxylase (ACCα) in the liver were down-regulated by dietary TFS. Conversely, the gene expressions of FAS and ACCα in the adipose tissue increased. The mRNA level of carnitine palmityl transferase-I (CPT-I) in adipose tissue was also increased by TFS. These results suggest that the addition of TFS at a dose of 4 g kg -1 improves growth performance and lowers lipid metabolism in finishing pigs.