A multifunctional transgenic Lactobacillus with probiotic characteristics and an ability to degrade β-glucan and phytic acid (phytate) was engineered to improve nutrient utilization, increase production performance and decrease digestive diseases in broiler chickens. The Bacillus subtilis WL001 endoglucanase gene (celW) and Aspergillus fumigatus WL002 phytase gene (phyW) mature peptide (phyWM) were cloned into an expression vector with the lactate dehydrogenase promoter of Lactobacillus casei and the secretion signal peptide of the Lactococcus lactis usp45 gene. This construct was then transformed into Lactobacillus reuteri XC1 that had been isolated from the gastrointestinal tract of broilers. Heterologous enzyme production and feed effectiveness of this genetically modified L. reuteri strain were investigated and evaluated. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed that the molecular mass of phyWM and celW was approximately 48.2 and 55 kDa, respectively, consistent with their predicted molecular weights. Endoglucanase and phytase activities in the extracellular fraction of the transformed L. reuteri culture were 0.68 and 0.42 U/mL, respectively. Transformed L. reuteri improved the feed conversion ratio of broilers from 21 to 42 days of age and over the whole feeding period. However, there was no effect on body weight gain and feed intake of chicks. Transformed L. reuteri supplementation improved levels of ash, calcium and phosphorus in tibiae at day 21 and of phosphorus at day 42. In addition, populations of Escherichia coli, Veillonella spp. and Bacteroides vulgatus were decreased, while populations of Bifidobacterium genus and Lactobacillus spp. were increased in the cecum at day 21.

Dietary fiber (DF) is an important nutrient component in pig’s diet that remarkably influences their growth and slaughter performance. The ability of pigs to digest DF depends on the microbial composition of the intestinal tract, particularly in the hindgut. However, studies on how DF alters the growth and slaughter performance of pigs by shaping the gut microbial composition and metabolites are still limited. Therefore, this study aimed to investigate the effects of DF on microbial composition, functions, and metabolites, ultimately altering host growth and slaughter performance using Durco × Bamei crossbred pigs supplemented with 0%, 10%, 17%, and 24% broad bean silage in the basic diet. We found that the final weight, average daily gain, fat, and lean meat weight significantly decreased with increasing DF. Pigs with the lowest slaughter rate and fat weight were observed in the 24% fiber-supplemented group. Gut microbial communities with the highest alpha diversity were formed in the 17% fiber group. The relative abundance of fiber-degrading bacteria, bile acid, and succinate-producing bacteria, including Prevotella sp., Bacteroides sp., Ruminococcus sp., and Parabacteroides sp., and functional pathways, including the butanoate metabolism and the tricarboxylic acid [TCA] cycle, significantly increased in the high-fiber groups. The concentrations of several bile acids significantly decreased in the fiber-supplemented groups, whereas the concentrations of succinate and long-chain fatty acids increased. Our results indicate that a high-fiber diet may alter the growth and slaughter performance of Durco × Bamei crossbred pigs by modulating the composition of Prevotella sp., Bacteroides sp., Ruminococcus sp., Parabacteroides sp., and metabolite pathways of bile acids and succinate.

The RNA-Seq technology was used to screen the key genes that affect the early development of the testes of Duroc × Landrace × Yorkshire piglets, to determine the regulatory pathway and provide reference for subsequent reproductive performance research, breeding, and other production practices. This study selected 14-day-old Duroc × Landrace × Yorkshire piglets as the trial animals. Testes from piglets with similar weights and no pathological changes were divided into small testis (ST) and large testis (LT) groups, and the RNA-Seq screening of differentially expressed genes (DEGs) was performed to find candidate genes and regulatory pathways related to early testicular development. The results show that 570 DEGs were found in the ST and LT groups, with 281 upregulated and 289 downregulated. The DEGs were mainly enriched on 47 gene ontology (GO) functional items. The Kyoto encyclopedia of genes and genotypes (KEGG) enrichment analysis found that there were 44 significantly enriched KEGG signal pathways, and the regulation of testicular development mainly focused on the arachidonic acid metabolism, Wnt signaling pathway and GnRH secretion pathways. The PTGES, SFRP1, SPP1, PLA2G4E, KCNJ5, PTGS2, and HCN1 genes were found to be as closely related to the testicular development of these Duroc × Landrace × Yorkshire piglets, and the differential gene expression was consistent with the real-time quantitative reverse transcription PCR (real-time qRT-PCR) validation results. This study was validated by high-throughput sequencing analysis and real-time qRT-PCR, and showed that the PTGES, SFRP1, SPP1, PLA2G4E, KCNJ5, PTGS2, and HCN1 genes may be involved in the regulation of germ cell development, spermatogenesis and semen traits. These should be further studied as candidate genes for early testicular development and reproductive trait regulation in boars.

This study aimed to evaluate the nutritional composition and fermentation quality of feed fermented by Bacillus amyloliquefaciens and Bacillus licheniformis as well as their effects on growth performance, meat quality, blood parameters, and gut microbiota in fattening pigs. A total of 72 healthy Duroc × Landrace × Large White crossbred barrows (68.78 ± 1.41 kg, p > 0.05 for initial body weight among groups) were randomly assigned to three dietary treatments, with four replicates pens per treatment and six pigs per pen. The pigs were fed one of three diets: (1) CK: 100% basal diet; (2) YR1: 50% basal diet + 50% feed fermented with Bacillus amyloliquefaciens YR3.2; and (3) YR2: 50% basal diet + 50% feed fermented with Bacillus licheniformis YR3.1. The experiment consisted of a 7-day adaptation period and a 50-day treatment period. The results showed that the crude protein, starch, lactic acid, acetic acid, and propionic acid contents were significantly higher in the treatment groups than in the control group (p < 0.05). The final body weight of fattening pigs, serum superoxide dismutase activity, and redness value of the longissimus dorsi muscle were significantly higher in the treatment groups than in the control group (p < 0.05). The carcass weight of the YR1 group was significantly higher than that of the other groups (p < 0.05). Moreover, the shear force of pork was significantly lower in the treatment groups than in the control group (p < 0.05). Microbial analysis showed that Firmicutes dominated the jejunum and cecum in all groups (>80%). In the YR1 group, the abundance of Clostridium increased in the jejunum, whereas the abundance of Terrisporobacter decreased. In the YR2 group, the abundances of both Clostridium and Terrisporobacter increased in the jejunum and cecum. In conclusion, fermented feed prepared with Bacillus amyloliquefaciens and Bacillus licheniformis has a positive effect on the growth performance of fattening pigs, but fermented feed prepared by Bacillus amyloliquefaciens YR3.2 has a more significant effect on improving growth performance, feed conversion efficiency and some meat quality indicators.

This study investigates the effects of inoculating a novel Lactobacillus complex, isolated from the yak rumen on the Qinghai-Tibet Plateau, on the quality