Preference and performance trials were conducted to investigate the effects of extruded corn with different degrees of gelatinization on the feed preference, growth performance, nutrient digestibility, and fecal microbiota of weaning piglets. In the preference trial, 144 piglets who were 35 days old were weighed and allotted to six treatments with four replications per treatment. Piglets in each treatment group were allowed to choose two of the following four corn-supplemented diets: conventional corn (NC) or extruded corn with low (LEC; 41.82% gelatinization), medium (MEC; 62.60% gelatinization), or high (HEC; 89.93% gelatinization) degrees of gelatinization for 18 days. The results showed that the piglets preferred diets supplemented with a low degree of gelatinization of extruded corn. In the performance trial, 144 piglets who were 35 days old were weighed and allotted into four treatments with six replications per treatment. Piglets in each treatment were fed one of the four diets for 28 days. The results showed that LEC and MEC decreased the feed:gain ratio at 14–28 days and 0–28 days, respectively, and increased the apparent total tract digestibility (ATTD) of crude protein compared with NC. Meanwhile, LEC increased the total protein and globulin content in the plasma on day 14, and MEC increased the ATTD of ether extract (EE) compared with NC. Extruded corn with low and medium degrees of gelatinization increased the abundance of Bacteroidetes at the phylum level and Lactobacillus, Alloprevotella, Prevotellaceae_UCG-03, and Prevotella_2 at the genus level. The results showed that extruded corn can improve feed preference, increase growth performance and nutrient digestibility, and modify gut microbiota, and the ideal degree of gelatinization is approximately 41.82–62.60%.

This study aimed to develop a multi-bioactive composite plant extract as an alternative to dietary antibiotics for application in animal production. Five plant materials were initially selected from 23 candidate plants via in vitro antibacterial, antioxidant, and anti-inflammatory screening, and formulated into three candidate extracts (C1, C2, C3) by orthogonal design, with respective dominant activities and moderate the other activities. Three feeding trials in mice demonstrated that administration of 1000 mg/kg C1 or C2 caused no adverse effects on hematological parameters or organ indexes. Supplementation with 250 mg/kg C1 or 125 mg/kg C2 significantly increased body weight gain and feed intake, reduced the feed-to-gain ratio, and modulated gut microbiota composition. In LPS-challenged mice, C1 and C2 restored jejunal villus height and crypt depth, downregulated the gene expression of TLR4, TNF-α, NF-κB, and IL-1β, and increased hepatic T-AOC activity while decreasing MDA content. Furthermore, a feeding trial in piglets demonstrated that dietary supplementation with 200 mg/kg C2 achieved growth performance comparable to that of conventional antibiotic supplementation, highlighting its potential as a substitute for feed antibiotics. In conclusion, this study has developed a new multi-bioactive composite plant extract that may serve as a promising alternative to feed antibiotics.

The objective of this study was to evaluate the effect of reducing dietary protein levels on barrows during the late fattening period. Fifty Duroc × Landrace × Yorkshire barrows with body weights averaging 76.30 ± 6.57 kg were randomly divided into normal protein (NP) and low protein (LP) groups. The feeding experiment lasted for 55 days. Dietary crude protein (CP) contents were 13.5% in the NP and 11.5% in the LP during days 1–28 and 12.5% and 10.5% during days 29–55, respectively. Results showed that compared with the NP, the LP increased the average daily gain (ADG) of barrows during days 29–55 (p < 0.05); enhanced the digestibility of nutrients, including dry matter (p < 0.01), CP (p < 0.01), calcium (p < 0.01), and phosphorus (p < 0.05); and decreased serum blood urea nitrogen (p < 0.01), total cholesterol (p < 0.05), and free fatty acids (p < 0.05). Lowering dietary CP increased fecal Lactobacillus abundance (p < 0.01); reduced concentrations of fecal ammonia nitrogen, histamine, butylamine, putrescine, 1,2-heptaenediamine, p-cresol, and indole-3-acetic acid (p < 0.01); and had no negative effects on meat quality (p > 0.05). These results suggested that reducing dietary CP by 2% could improve growth, promote efficient nutrient utilization, increase beneficial fecal microbiota abundance, and reduce the emission of fecal malodorous compounds in late-fattening barrows.