Lactic acid bacteria (LAB) as probiotic candidates have various beneficial functions, such as regulating gut microbiota, inhibiting intestinal pathogens, and improving gut immunity. The colonization of the intestine is a prerequisite for probiotic function. Therefore, it is necessary to screen the highly adherent LAB. In this study, the cell surface properties, such as hydrophobicity, auto-aggregation, co-aggregation, and adhesion abilities of the six chicken-derived LAB to Caco-2 cells were investigated. All six strains showed different hydrophobicity (21.18–95.27%), auto-aggregation (13.61–30.17%), co-aggregation with Escherichia coli ATCC 25922 (10.23–36.23%), and Salmonella enterica subsp. enterica serovar Typhimurium ATCC 13311 (11.71–39.35%), and adhesion to Caco-2 cells (8.57–26.37%). Pediococcus pentosaceus 2–5 and Lactobacillus reuteri L-3 were identified as the strains with strong adhesion abilities (26.37% and 21.57%, respectively). Moreover, these strains could survive in a gastric acid environment at pH 2, 3, and 4 for 3 h and in a bile salt environment at 0.1%, 0.2%, and 0.3% (w/v) concentration for 6 h. Furthermore, the cell-free supernatant of P. pentosaceus 2–5 and L. reuteri L-3 inhibited the growth of enteropathogenic bacteria and the strains inhibited the adhesion of these pathogens to Caco-2 cells. In this study, these results suggested that P. pentosaceus 2–5 and L. reuteri L-3, isolated from chicken intestines might be good probiotic candidates to be used as feed additives or delivery vehicles of biologically active substances.

Probiotics are the most promising alternative to antibiotics for improving animal production and controlling pathogenic infections, while strains derived from natural hosts are considered highly desirable due to their good adaptation to the gastrointestinal tract. The aim of this study was to screen Lactobacillus with broad-spectrum antibacterial activity from broilers fed an antibiotic-free diet and evaluate their potential as poultry probiotics. A total of 44 lactic acid bacteria (LAB) strains were isolated from the intestines of healthy broilers, among which 3 strains exhibited outstanding antimicrobial activity and were subsequently identified through 16S rRNA sequencing as Enterococcus faecium L8, Lactiplantibacillus plantarum L10, and Limosilactobacillus reuteri H11. These three isolates demonstrated potent bacteriostatic activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella cholerae, with inhibition zones ranging from 15.67 ± 1.53 to 21.33 ± 0.58 mm. The selected LAB strains exhibited high tolerance to acid and bile salts, with L. reuteri H11 displaying the highest survival rate (ranging from 34.68% to 110.28%) after exposure to 0.3% (w/v) bile salts for 6 h or a low pH environment (pH 2, 2.5, and 3) for 3 h. Notably, L. reuteri H11 outperformed other strains in terms of hydrophobicity (84.31%), auto-aggregation (53.12%), and co−aggregation with E. coli ATCC 25922 (36.81%) and S. aureus ATCC 6538 (40.20%). In addition, the three LAB isolates were either fully or moderately susceptible to the tested antibiotics, except for strain L8, which resisted gentamycin and vancomycin. Consequently, these three LAB strains, especially L. reuteri H11, isolated from the intestines of broiler chickens, represent promising probiotic candidates that can be employed as feed additives to enhance production performance and control poultry pathogens.

Fermentation and enzymolysis are commonly used biological treatment methods to treat forage, especially unconventional one. Both these treatments can improve the nutritional value of the forage, reduce the content of anti-nutritional factors and ameliorate the digestibility of feed....

The use of inorganic copper in feed is hazardous. As probiotics of animals, Candida utilis can absorb copper ions and transform them to organic copper. This study aimed to domesticate the ability of C. utilis (CICC 32211) to absorb and transform copper ions. So, C. utilis (CICC 32211) was cultured in media with different concentrations of copper ions for 24, 48 and 72 h to identify the optimum copper ion concentration. C. utilis (CICC 32211) strains were domesticated for three generations, then the absorption and distribution of copper ions in the yeast cells were studied. We found that the optimum concentration of copper ions was 110 µg/mL. After 48 h, the number of yeast cells was low, but copper ion absorption efficiency was maximized (43.83%). Most of the enriched copper ions were distributed in the yeast cell wall (up to 30.58% when grown in the medium with 110 µg/mL copper ions), while the intracellular copper ion content was low (2.095%). High concentrations of copper ions affected the morphological structure, element content and distribution of yeast cells.

Effect of Cellulase Genes Recombinant L. reuteri on Digestibility of Diet Crude Fiber and Adhesion in Gut of Chicken

Recombinant Lactobacillus could play the role of a probiotic besides other new functions. This experiment aimed to study the gut adhesion ability of recombinant Lactobacilli and its effect on the digestibility of crude fibre in chicks. The adhesion ability of Lactobacilli was observed through in vitro and in vivo tests. Intestinal epithelial cells and recombinant Lactobacillus were co-cultured for observation of adhesion in the in vitro study. A total of 100 one-d-old chicks were randomly divided into four equal groups, namely, C15, C73, C15–73 and control. Each chick in C15, C73, C15–73 and control groups were orally gavaged with 200 μL each of fermentation broth of recombinant Lactobacillus reuteri XNY-Cel15 (C15), recombinant Lactobacillus reuteri XNY-Cel73 (C73) and both containing 100 μl each of XNY-Cel15 and XNY-Cel73 (C15B), or 200 μL of MRS broth (control), respectively, once at the beginning of the trial. The digestibility of crude fibre was determined through a digestion trial. Results of in vitro study showed that recombinant Lactobacillus reuteri adhered to chick intestinal epithelial cells. After feeding for 30 d, the reporter genes of recombinant Lactobacillus were detected in the crop, small intestine, and cecum of chicks, with their sequences corresponding to those of the insert genes. The digestibility of crude fibre in the experimental groups was higher than that in the control group, and the digestibility in C15 group was significantly (P<0.01) higher than other groups. It is concluded that the recombinant Lactobacillus can survive in the digestive tract of chicken for more than 30 d, and help to degrade the crude fibre in the digestive tract.