Inclusion of Lacticaseibacillus paracasei NSMJ15 in broiler diets induces changes in jejunal immune cell population and cecal microbiota.

Objective: The objective was to investigate growth performance, antioxidant enzyme activity, intestinal morphology, immune cell distribution, short chain fatty acid (SCFA) profile, and microbiota in broiler chickens fed a diet containing Lacticaseibacillus paracasei NSMJ15. Methods: A total of 120-day-old Ross 308 male broilers were allocated to 2 dietary treatments in a randomized complete block design. A control group was fed a corn-soybean meal control diet, and an NSMJ15-supplemented group was fed a control diet supplemented with 1 g/kg L. paracasei NSMJ15 at the expense of cornstarch. Each dietary treatment had 6 replicates with 10 birds per cage. Growth performance was recorded on day 9. On day 10, one bird representing median body weight was selected to collect serum for antioxidant enzyme activity, jejunal tissue for immune cell isolation and morphometric analysis, and cecal digesta for 16S rRNA gene sequencing and SCFA analysis. Results: Supplementation of L. paracasei NSMJ15 did not affect growth performance, serum antioxidant enzyme activity, and jejunal histomorphology compared to the control group. In the NSMJ15-supplemented group, the population of CD3+CD4+CD8- T cells increased (p=0.010), while the population of CD3+CD8+TCRγδ+ T cells decreased (p=0.022) compared to the control group. The L. paracasei NSMJ15 supplementation decreased (p=0.022) acetate concentration in the cecal digesta compared to the control group. The 16S rRNA gene sequencing analysis showed that NSMJ15-supplemented group differentially expressed (p<0.05) 10 more amplicon sequence variants compared to control group without affecting alpha and beta diversity indices of the cecal microbiota. Genera Mediterraneibacter and Negativibacillus were positively (p<0.05) correlated with CD4+ T cells, while genera Gemmiger, Coprococcus, Sellimonas, Massilimicrobiota, and Blautia were negatively (p<0.05) correlated with SCFA concentration. Conclusion: The results of the present study suggest dietary L. paracasei NSMJ15 supplementation may increase percentage of CD4+ T cells and decrease acetate concentration in broiler chickens by increasing the differential expression of specific microbial genera.

Intestinal Immune Cell Populations, Barrier Function, and Microbiomes in Broilers Fed a Diet Supplemented with Chlorella vulgaris.

This study aimed to evaluate the effects of dietary Chlorella vulgaris (CV) on the distribution of immune cells, intestinal morphology, intestinal barrier function, antioxidant markers, and the cecal microbiome in 10-day-old broiler chickens. A total of 120 day-old Ross 308 male broiler chicks were assigned to two dietary treatments using a randomized complete block design, with body weight as the blocking factor. Birds fed a diet containing CV showed an increase in CD4+ T cells (p < 0.05) compared to those fed the control diet. The relative mRNA expression of intestinal epithelial barrier function-related markers (occludin and avian ß-defensin 5) was elevated (p < 0.05) in the CV-supplemented group compared to the control group. The alpha diversity indices (Chao1 and observed features) of the cecal microbiome in 10-day-old birds increased (p < 0.05), indicating higher richness within the cecal bacterial community. In the microbiome analysis, enriched genera abundance of Clostridium ASF356 and Coriobacteriaceae CHKCI002 was observed in birds fed the diet containing CV compared to those fed the control diet. Taken together, dietary CV supplementation might alter intestinal barrier function, immunity, and microbiomes in 10-day-old broiler chickens.

The Modulatory Effects of Lacticaseibacillus paracasei Strain NSMJ56 on Gut Immunity and Microbiome in Early-Age Broiler Chickens.

Gut health has been attracting attention in the livestock industry as several studies suggest that it is a crucial factor for growth performance and general health status in domestic animals, including broiler chickens. Previously, antibiotics were widely used to improve livestock growth, but their use is now prohibited due to serious problems related to antibiotic resistance. Thus, finding new feed additives to replace antibiotics is drawing attention. Probiotics are representative feed additives and many beneficial effects on broiler chickens have been reported. However, many probiotic studies are focused on productivity only, and there are insufficient studies related to the gut environment, especially gut immunity and gut microbiome. In this study, we conducted an animal experiment using Lacticaseibacillus paracasei NSMJ56 to determine whether it has beneficial effects on gut immunity and microbiome. To evaluate the effects of NSMJ56 supplementation, newly hatched Ross 308 broiler chickens were fed an NSMJ56-containing diet for 10 days, and growth performance, antioxidant indicators, gut morphology, gut immunity-related parameters, and gut microbiome were analyzed. Flow cytometry analysis results revealed that NSMJ56 treatment increased CD4+ T cells and decreased CD8+ T cells in small intestine lamina propria and decreased IL1b and IL10 gene expression in small intestine tissue. In the microbiome analysis, NSMJ56 treatment increased the alpha diversity indices and led to three enriched genera: Massilimicrobiota, Anaerotignum, and Coprococcus. This study suggests that NSMJ56 supplementation has regulatory effects on gut immunity and microbiome in early-age broiler chickens.