Evaluating two multistrain probiotics on growth performance, intestinal morphology, lipid oxidation and ileal microflora in chickens

Direct-fed Microbials (DFM) and Poultry Genomics: A Synergistic Approach to Sustainable Antibiotic Free Farming

Improper usage of antibiotics in poultry production is a great threat to the ecosystem because their residues can enter into the food chain or leach into soil or water systems and increase antibiotic resistance risks. Hence, direct-fed microbials (DFMs) have gained recognition as a sustainable and viable alternative to antibiotics in poultry production, capitalizing on the relationship between microbial genetics, host genomics, and gut microbiota. This review delves into the genetic and host genomic mechanisms through DFMs effects including the enhancement of nutrient metabolism, modulation of gut microbiota and strengthening of the host immunity. The revolution of multi-omics has participated in the identification of probiotic strains with desirable traits and revealed their impact on host gene expression, particularly in genes related to intestinal health, such as tight junction proteins and mucins. Furthermore, the review summarizes the benefits of using DFMs in poultry production, the factors affecting their efficacy and their challenges and limitations. Future research integrating host and microbial genomics, along with precision microbiome engineering, holds promise for maximizing the potential of DFMs in advancing sustainable poultry farming practices.

Impact of multistrain probiotics on growth performance, immune response, and gut morphometry in broiler chicken Gallus gallus domesticus

The objective of this investigation was to examine the impact of four lab-isolated probiotics Enterococcus faecium (OR563785.1), Weissella confusa (OR563786.1), Weissella cibaria (OQ543569.1), Lactiplantibacillus plantarum (OQ689085.1) in 1:1:1:1 of CFU dilution as multistrain probiotics (MSP) regarding growth performance, haemato-biochemical indices and immune function in broilers. Ninety uniformly weighed broilers were divided into five groups at random with (n = 18/group). NC: negative control (basal diet); PC: commercial probiotic, G1: MSP supplemented, G2: MSP + vaccinated, G3: (vaccinated). Blood samples were collected at 42 days of age to assess immunological, haemato-biochemical parameters, and intestinal morphometry. Compared to the group of negative control, the broiler chicks' body weight was considerably (p < 0.05) higher in MSP-treated groups (G1, G2). This study found that, as compared to the NC, there was a substantial rise (p < 0.05) in RBC and hemoglobin in the probiotic-supplemented bird group. The results indicated that cholesterol and triglyceride remarkably decreased compared to control in probiotic-treated groups. There was no discernible change in the enzyme activity of ALT, AST, and ALP across the groups (p > 0.05). The findings indicated higher levels of immunoglobulin and interleukins in the MSP group than in the control (NC). The villus's height to crypt depth ratio was higher in the MSP groups (G1, G2) in contrast with the PC group (p < 0.05). The haemagglutination inhibition test (HI) revealed that the probiotic-treated groups had greater New Castle disease virus (NDV) antibodies than the other groups. The humoral response to live NDV vaccinations may be enhanced by multistrain probiotics. These results revealed MSP significantly affected growth performance, haematobiochemical parameters, and immunity through alteration in intestinal morphology which helps in nutrient uptake.

Impact of gut microbial diversity on egg production performance in chickens

Chickens are one of the most economically important poultry species, and their egg-laying performance is a crucial economic trait. The intestinal microbiome plays a significant role in the egg-laying performance. To clarify the diversity of chicken intestinal microbiota and its connection to egg-laying performance, this study utilized 16S rRNA sequencing technology to characterize the intestinal microbiomes of 101 chickens from 13 breeds with varying levels of egg production. The results reveal significant differences in gut microbiota structure among chicken groups with varying egg production levels. High egg-producing chickens showed significantly higher abundances of Firmicutes, Proteobacteria, and Lactobacillus, while low egg-producing chickens displayed greater microbial α-diversity and more complex community structures. These differences in gut microbiota influence key physiological functions, including nutrient absorption and hormone regulation through metabolic pathways, and directly affect egg production performance. The low and medium production groups partially overlapped on the principal coordinates analysis plot, whereas the high-production group was distinctly separate. This study provides a scientific basis and intestinal microbiome data for selecting probiotics related to high egg production in chickens.

IMPORTANCE

This study elucidates the critical role of gut microbiota in the egg-laying performance of chickens, a key economic indicator in the poultry industry. By employing 16S rRNA sequencing, we uncovered distinct microbial profiles associated with varying levels of egg production. High egg-producing chickens exhibit a higher abundance of specific bacterial taxa, such as Firmicutes and Proteobacteria, which are linked to enhanced nutrient absorption and metabolic efficiency. Conversely, lower and medium egg-producing chickens display greater microbial diversity, suggesting a more complex but less efficient gut ecosystem. Our findings provide valuable insights into the relationship between gut microbiota and egg production, offering a scientific foundation for the selection of probiotics that could potentially improve the egg-laying performance of chickens. This research not only advances our understanding of avian gut microbiology but also has practical implications for optimizing poultry farming practices and enhancing economic outcomes.

Metabolic interactions of Limosilactobacillus reuteri ZJ625 and Ligilactobacillus salivarius ZJ614 in co-culture: implications for multi-strain probiotics

AIMS

Limosilactobacillus reuteri ZJ625 and Ligilactobacillus salivarius ZJ614 are potential probiotic bacteria. The mechanisms of enhanced benefits by muti-strain probiotics are yet fully understood. We elucidated the influence of co-culturing on the metabolite profiles of Limosilactobacillus reuteri ZJ625 and Ligilactobacillus salivarius ZJ614 to decipher the impacts of co-culturing on metabolic interactions between the strains.

METHODS AND RESULTS

Limosilactobacillus reuteri ZJ625 and Ligilactobacillus salivarius ZJ614 were grown in single and co-cultures in defined media. Bacterial cell metabolites were extracted at the mid-stationary growth phase and analysed using two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS). Mass-spectral data were preprocessed and analysed using unsupervised and supervised methods based on the group allocations. A total of 1387 metabolites were identified, with 18.31% significant metabolites (P < 0.05) and 10.17% differential metabolites (P < 0.05, variable importance on projection > 1). The differential metabolites identified include arabinofuranose, methyl-galactoside, N-acetylglutamic acid, phosphoric acid, and decanoic acid. The metabolites impacted carbohydrate and amino-sugar metabolism.

CONCLUSION

Co-culturing of Limosilactobacillus reuteri ZJ625 and Ligilactobacillus salivarius ZJ614 influenced the metabolite profiles of the strains and impacted metabolic/biosynthetic pathways, indicating cell-to-cell interactions between the strains.

Effect of different levels of single cell protein and probiotic microorganisms on performance, immunological responses, and intestinal histology in laying hens

An experiment was conducted to evaluate the effects of single-cell protein (SCP), as a valuable by-product and substitute for soybean meal, and multistrain probiotics on the performance, blood biochemistry, intestinal histomorphology, ileal microbiota, and immune responses in laying hens. Leghorn laying hens were randomly assigned to nine experimental treatments with eight replicates of five birds each. Dietary treatments consisted of three levels of replacement of soybean meal with SCP (0.0%, 30%, and 60%) and three levels of probiotics (0.0, 50, 100 mg/kg) offered through 70 days of main recording. The result indicated that replacing 30% soybean meal with SCP in the diet significantly increased the eggshell weight, thickness, and strength; however, hens receiving 60% SCP replacement showed lower productive performance. During the second 35-d trial, hens receiving at least 50 mg/kg probiotics produced higher eggshell weight, thickness, and strength than the control hens. Remarkable lower levels of serum cholesterol content were observed in the SCP and probiotic-supplemented diets. The significant reduction in the ileal pH, Escherichia coli and Clostridium spp. enumerations and a remarkable increase in Lactobacillus count was observed after feeding incremental levels of probiotics. The highest villus height to crypt depth ratio, antibody titer against sheep red blood cells (in secondary response) and Newcastle disease vaccine, as well as egg production and egg mass, were found in the hens that received 30% SCP replacement in combination with 50 or 100 mg/kg probiotic (SCP × Probiotic). The present study concluded that feeding SCP, as a cheap protein alternative source, along with probiotics while reducing production costs can support productive performance via modulating the intestinal microbiomes and health indices and fortifying the immune system in laying hens.

Effects of Tibetan Sheep-Derived Compound Probiotics on Growth Performance, Immune Function, Intestinal Tissue Morphology, and Intestinal Microbiota in Mice

Probiotics play an important role in animal growth, immunity, and gut microbial balance and are now widely used in agriculture, food, and medicine. This study analysed the effects of different concentrations of Tibetan sheep compound probiotics on the immunity, tissue morphology, and intestinal microbiota of mice using histological, molecular, and 16S rRNA techniques. The results showed that the composite probiotics sourced from Tibetan sheep improved the growth performance of mice, increased the length of small intestinal villi and mucosal thickness, and enhanced the intestinal barrier function of mice. DZ-L and DZ-M significantly increased the mRNA expression levels of ZO-1, Occludin, and Claudin-1 mRNA. They also up-regulated IL-10 and TNF-β, and down-regulated TNF-α, IL-1β, and IL-8. The immune function of mice was enhanced, with DZ-M treatment having an extremely significant effect, while the effect of DZ-H treatment was slightly lower compared to DZ-L and DZ-M. In addition, the composition and diversity of the intestinal microbiota were modulated, and at the phylum level, the relative abundance of Firmicutes was higher in the DZ-M group, the relative abundance of Desulfobacterota, Actinobacteriota, and Patescibacteria was reduced in the probiotic complex group, and the relative abundance of Verrucomicrobiota was higher. At the genus level, the relative abundance of Muribaculaceae was higher in the DZ-L and DZ-M groups, and the relative abundance of Lachnospiraceae_NK4A136_group in the DZ-H group; and the relative abundance of Bacteroides and Roseburia in the composite probiotic group. This study can improve the reference for the development of new green feed additives instead of antibiotics, which will also further promote the development of the livestock industry.

Dietary Lactobacillus reuteri SL001 Improves Growth Performance, Health-Related Parameters, Intestinal Morphology and Microbiota of Broiler Chickens

It was assumed that dietary inclusion of Lactobacillus reuteri SL001 isolated from the gastric contents of rabbits could act as an alternative to feed antibiotics to improve the growth performance of broiler chickens. We randomly assigned 360 one-day-old AA white-feathered chicks in three treatments: basal diet (control), basal diet plus zinc bacitracin (antibiotic), and basal diet plus L. reuteri SL001 (SL001) treatment. The results showed the total BW gain and average daily gain (ADG) of broilers in SL001 treatment increased significantly (p < 0.05, respectively) compared with the control group from day 0 to 42. Moreover, we observed higher levels of immune globulins in both the SL001 group and the antibiotic group. Total antioxidant capacity and levels of antioxidant factors were also significantly increased (p ≤ 0.05, respectively) in the SL001 treatment group, while the interleukin 6, interleukin 4, creatinine, uric acid, total cholesterol, triglyceride, VLDL, LDL and malondialdehyde were remarkably decreased (p < 0.05, respectively). In the ileum of SL001 treatment broilers, the height of villi and the ratio of villi height to crypt depth were significantly increased (p < 0.05). Meanwhile, the crypt depth reduced (p < 0.01) and the ratio of villi height to crypt depth increased (p < 0.05) in the jejunum compared to the control. The abundance of microbiota increased in the gut of broilers supplemented with SL001. Dietary SL001 significantly increased the relative abundance of Actinobacteria in the cecal contents of broilers (p < 0.01) at the phylum level. In conclusion, L. reuteri SL001 supplementation promotes the growth performance of broiler chickens and exhibits the potential application value in the industry of broiler feeding.

Evaluation of the antibacterial activity of Weissella confusa K3 cell-free supernatant against extended-spectrum βeta lactamase (ESBL) producing uropathogenic Escherichia coli U60

Different strategies have been approved for controlling extended-spectrum βeta lactamase (ESBL) producing uropathogenic bacteria. The antibacterial activity of Lactic acid bacteria (LAB) is an effective strategy due to its probiotic characteristics and beneficial effects on human health. The antibiotic susceptibility test, disk diffusion method, and double disc synergy test indicated that five enteric uropathogenic isolates were ESBL producers during the present study. They recorded diameters of inhibition zones as ≤ 18, ≤ 8, ≤ 19, and ≤ 8 mm against cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), and ceftriaxone (CRO). Genotypically, blaTEM genes are the most common, with (100 %) occurrence in all the five enteric tested uropathogens, followed by blaSHV and blaCTX genes (60 %). In addition, out of 10 LAB isolates from dairy products, the CFS of isolate no. K3 had high antibacterial activity against the tested ESBLs, especially no. U60, with a MIC of 600 µl. Additionally, the MIC and sub-MIC of K3 CFS inhibited the production of antibiotic-resistant bla TEM genes of U60. Analyzing the 16S rRNA sequence confirmed that the most potent ESBL-producing bacteria (U60) and LAB (K3) isolates were identified as Escherichia coli U60.1 and Weissella confuse K3 with accession numbers MW173246 and MW173299.1, respectively, in GenBank.

Diet Composition and Using Probiotics or Symbiotics Can Modify the Urinary and Faecal Nitrogen Ratio of Broiler Chicken's Excreta and Also the Dynamics of In Vitro Ammonia Emission

The objective of this research was to determine whether diet composition, or adding probiotic or symbiotic feed additives to broiler diets can modify the N composition of the excreta and the dynamics of ammonia volatilization from the manure. A total of 574 one-day-old Ross 308 broiler chickens were fed four different diets. The treatments included a corn and soybean meal-based control diets (C), wheat-based and wheat bran containing diets (W), a multi-strain probiotic treatment (Broilact^®; Br), and a symbiotic additive containing Bacillus subtilis, inulin, and Saccharomices cerevisiae (Sy). Feeding the wheat-based diet significantly improved the weight gain and FCR of chickens. Treatment W also significantly increased the dry matter content of the excreta compared with the probiotic and symbiotic treatments. Both Br and Sy tended to decrease the amount of excreted uric acid, which is the main substrate of ammonia. Treatment Sy reduced the urinary N ratio of the excreta in comparison with treatment W. The symbiotic additive resulted in significantly higher ammonia emission in the first two hours. On the other hand, the dynamics of the emission was slow at the beginning and increased steeply after 15 h when the wheat-based diets were fed. Based on our results, the wheat-based diets, containing soluble arabinoxylans, and the symbiotic treatments of broiler diets have an impact on the urinary and faecal nitrogen composition of the excreta, and also on the dynamics of ammonia release from the manure.

Effects of three different probiotics of Tibetan sheep origin and their complex probiotics on intestinal damage, immunity, and immune signaling pathways of mice infected with Clostridium perfringens type C

Tibetan sheep have unique intestinal microorganisms in their intestines that are adapted to the highland alpine and anoxic environment. To further clarify the probiotic properties of Tibetan sheep-derived probiotics, we selected three Tibetan sheep-derived probiotic isolates (Enterococcus faecalis EF1-mh, Bacillus subtilis BS1-ql, and Lactobacillus sakei LS-ql) to investigate the protective mechanisms of monocultures and their complex strains against Clostridium perfringens type C infection in mice. We established a model of C. perfringens type C infection and used histology and molecular biology to analyze the effects and mechanisms of different probiotic treatments on mice after C. perfringens type C infection. After supplementation with either probiotics or complex probiotics, mice were improved in terms of weight reduction and reduced the levels of cytokines in serum and increased the levels of intestinal sIgA, and supplementation with complex probiotics was effective. In addition, both probiotic and complex probiotic supplementation effectively improved the damage of intestinal mucosa and spleen tissue. The relative expressions of Muc 2, Claudin-1, and Occludin genes were increased in the ileum. The three probiotics and the compound probiotics treatment significantly reduced the relative mRNA expression of toll-like/MyD88/NF-κB/MAPK. The effect of probiotic treatment was similar to the results of engramycin treatment, but the effect of engramycin treatment on intestinal sIgA was not significant. Our results clarify the immunomodulatory effects of the three probiotic isolates and the complex probiotics on C. perfringens infection, and the repair of the intestinal mucosal barrier.

Probiotics in Poultry Nutrition as a Natural Alternative for Antibiotics

Since the early 1950s, antibiotics have been used in poultry for improving feed efficiency and growth performance. Nevertheless, various side effects have appeared, such as antibiotic resistance, antibiotic residues in eggs and meat, and imbalance of beneficial intestinal bacteria. Consequently, it is essential to find other alternatives that include probiotics that improve poultry production. Probiotics are live microorganisms administered in adequate doses and improve host health. Probiotics are available to be used as feed additives, increasing the availability of the nutrients for enhanced growth by digesting the feed properly. Immunity and meat and egg quality can be improved by supplementation of probiotics in poultry feed. Furthermore, the major reason for using probiotics as feed additives is that they can compete with various infectious diseases causing pathogens in poultry's gastrointestinal tract. Hence, this chapter focuses on the types and mechanisms of action of probiotics and their benefits, by feed supplementation, for poultry health and production.

Effects of a direct fed microbial (DFM) on broiler chickens exposed to acute and chronic cyclic heat stress in two consecutive experiments

Two consecutive 35 d experiments were conducted to investigate the effects of a multistrain DFM fed continuously to broiler chickens exposed to HS from 28 to 35 d on broiler performance, body composition, ileal digestibility, and intestinal permeability using serum Fluorescein Isothiocyanate Dextran (FITC-d) concentration. The treatments were arranged as a 2 × 2 factorial with temperature: Elevated (HS: 33 ± 2°C for 6 h and 27.7°C for the remaining 18 h from 28 to 35 days of age) and Thermoneutral (TN: 22 to 24°C over the entire 24-h day from 28 to 35 days of age) and diet: corn-soybean meal based with and without DFM (3-strain Bacillus; Enviva PRO) fed over the entire 35-d period as the two factors. Experimental diets were formulated to meet all nutrient recommendations based on breed standards using a starter (0–10 d), grower (10–21 d), and finisher (21–35 d) period. For each of the 2 experiments, 648 Ross 708 broiler chicks were allotted among the treatments with 9 replicate pens of 18 broilers. Data were analyzed as a 2 × 2 factorial within each experiment in JMP 14. In both experiments, cloacal temperatures were increased (P ≤ 0.05) in the broilers subjected to the HS treatment at both 28 d (acute) and 35 d (chronic). Supplementing birds with DFM reduced cloacal temperatures in the Experiment 1 at 28 d, but not at the other time periods. The HS treatment reduced body weight gain and lean tissue accretion from 0 to 35 d in both experiments (P ≤ 0.05). In Experiment 2, when the litter was reused BWG was increased by 36 g/bird with supplementation of DFM (P ≤ 0.05). Ileal digestibility at 28 d (2 h post HS) was improved with DFM supplementation in both experiments (P ≤ 0.05). Serum FITC-d increased with HS at both 28 and 35 d. Serum FITC-d was generally decreased with DFM at 28 d but the response was inconsistent at 35 d. Overall, the results suggest that HS reduced broiler performance and DFM treatment improved intestinal permeability and nutrient digestibility responses to HS in both experiments but did not improve performance until built up litter was used in Experiment 2.

Bacillus spp. Probiotic Strains as a Potential Tool for Limiting the Use of Antibiotics, and Improving the Growth and Health of Pigs and Chickens

The pressure to increasingly optimize the breeding of livestock monogastric animals resulted in antimicrobials often being misused in an attempt to improve growth performance and counteract diseases in these animals, leading to an increase in the problem of antibiotic resistance. To tackle this problem, the use of probiotics, also known as direct in-feed microbials (DFM), seems to be one of the most promising strategies. Among probiotics, the interest in Bacillus strains has been intensively increased in recent decades in pigs and poultry. The aim of the present review was to evaluate the effectiveness of Bacillus strains as probiotics and as a potential strategy for reducing the misuse of antibiotics in monogastric animals. Thus, the potential modes of action, and the effects on the performance and health of pigs (weaning pigs, lactation and gestation sows) and broilers are discussed. These searches yielded 131 articles (published before January 2021). The present review showed that Bacillus strains could favor growth in terms of the average daily gain (ADG) of post-weaning piglets and broilers, and reduce the incidence of post-weaning diarrhea in pigs by 30% and mortality in broilers by 6-8%. The benefits of Bacillus strains on these parameters showed results comparable to the benefit obtained by the use of antibiotics. Furthermore, the use of Bacillus strains gives promising results in enhancing the local adaptative immune response and in reducing the oxidative stress of broilers. Fewer data were available regarding the effect on sows. Discordant effects have been reported regarding the effect on body weight (BW) and feed intake while a number of studies have supported the hypothesis that feeding probiotics to sows could benefit their reproductive performance, namely the BW and ADG of the litters. Taken all the above-mentioned facts together, this review confirmed the effectiveness of Bacillus strains as probiotics in young pigs and broilers, favoring their health and contributing to a reduction in the misuse of direct in-feed antibiotics. The continuous development and research regarding probiotics will support a decrease in the misuse of antibiotics in livestock production in order to endorse a more sustainable rearing system in the near future.

Novel mono- and multi-strain probiotics supplementation modulates growth, intestinal microflora composition and haemato-biochemical parameters in broiler chickens

Background

The reduction of antimicrobial usage in food‐producing animals necessitates the intense search for novel alternatives, including new probiotic strains with more effective properties in improving growth performance and curtailing diseases in animals.

Objective

This study evaluated the effects of novel mono‐ and multi‐strain probiotics on the growth performance, intestinal microbiota and haemato‐biochemical parameters of broilers.

Methods

A total of 160 one‐day‐old Cobb 500 broilers were divided into eight treatment groups with two replicates consisting of (1) basal diet (negative control), (2) basal diet with antibiotic, colistin sulphate, (3) basal diet with commercial probiotic, PROMAX® (positive control), (4) basal diet with Pediococcus acidilactici I5, (5) basal diet with P. pentosaceus I13, (6) basal diet with Enterococcus faecium C14, (7) basal diet with Lactobacillus plantarum C16 and (8) basal diet with the combination of all the four probiotic strains. Birds were kept for 35 days and through oral gavage, 1 ml of 108 study probiotic strains administered on days 3–6, 14 and 18.

Results

Supplementation with P. pentosaceus I13, L. plantarum C16 or multi‐strain probiotics significantly (p < 0.05) improved the body weight gain and feed conversion ratio with decrease in feed intake and intestinal Enterobacteria counts. There was a significant (p < 0.05) increase in haemoglobin, mean corpuscular volume, total white blood cells, platelets counts and a lowered (p < 0.05) total cholesterol and glucose levels in multi‐strains probiotic supplemented birds.

Conclusion

The supplementation with novel multi‐strain probiotics improved growth, intestinal health and haemato‐biochemical parameters in broilers and could be used as suitable antibiotic alternatives.

Positive Influence of a Probiotic Mixture on the Intestinal Morphology and Microbiota of Farmed Guinea Fowls (Numida meleagris)

To understand the effectiveness of a probiotic mixture on intestinal morphology, mucus layer composition, and cecal microbiota diversity, 40 10-day-old Guinea fowls (Numida meleagris) were assigned to two groups: the control group (C), receiving drinking water, and the treated group (P), receiving water plus a commercial multi-strain probiotic (Slab51®, 2 × 10¹¹ CFU/L). Birds were slaughtered after 4 months, and the intestines were collected. Samples from the duodenum, ileum, and cecum were processed for morphological and morphometric studies, and conventional glycohistochemistry. Cecal samples were also used to assess the microbiota by 16S metataxonomic approach. Group P showed significant increase in the villus height (p < 0.001 in the duodenum and p < 0.05 in the ileum and cecum), villus width (p < 0.05 in all investigated tracts), depth of crypts (p < 0.001 in the duodenum and cecum; p < 0.05 in the ileum), and goblet cells per villus (p < 0.001 in all investigated tracts) compared with group C. Cecal microbiota of the birds varied considerably and comparing the relative abundance of the main observational taxonomic units (OTUs), a positive enrichment of several beneficial taxa, such as Oscillospira, Eubacterium, Prevotella, and members of the Ruminococcaceae, was observed. The enrichment of those taxa can improve microbiota stability and resilience facing environmental stresses, enhancing its resistance against invading pathogens. Ruminococcaceae, which represent the most important taxon in both groups, and Prevotella have a key role in the gut physiology due to the production of short-chain fatty acids (SCFAs), which are a vital energy source for enterocytes, improve glucose metabolism, and exert an overall anti-inflammatory effect. Probiotic administration enriches the presence of Coprococcus, Oscillospira, and Eubacterium taxa that produce butyrate, which exerts a beneficial effect on growth performance, structure of villi, and pathogen control and has anti-inflammatory properties too. This study indicates that Slab51® supplementation positively affects the morphology and microbiota diversity of the guinea fowl intestine.

The Recent Trend in the Use of Multistrain Probiotics in Livestock Production: An Overview

It has been established that introducing feed additives to livestock, either nutritional or non-nutritional, is beneficial in manipulating the microbial ecosystem to maintain a balance in the gut microbes and thereby improving nutrient utilization, productivity, and health status of animals. Probiotic use has gained popularity in the livestock industry, especially since antimicrobial growth promoter's use has been restricted due to the challenge of antibiotic resistance in both animals and consumers of animal products. Their usage has been linked to intestinal microbial balance and improved performance in administered animals. Even though monostrain probiotics could be beneficial, multistrain probiotics containing two or more species or strains have gained considerable attention. Combining different strains has presumably achieved several health benefits over single strains due to individual isolates' addition and positive synergistic adhesion effects on animal health and performance. However, there has been inconsistency in the effects of the probiotic complexes in literature. This review discusses multistrain probiotics, summarizes selected literature on their effects on ruminants, poultry, and swine productivity and the various modes by which they function.

Relative Effects of Dietary Administration of a Competitive Exclusion Culture and a Synbiotic Product, Age and Sampling Site on Intestinal Microbiota Maturation in Broiler Chickens

In this research, the effects of early post-hatch inoculation of a competitive exclusion product (Br) and the continuous feeding of a synbiotic supplement (Sy) containing probiotic bacteria, yeast, and inulin on the production traits and composition of ileal chymus (IC), ileal mucosa (IM), and caecal chymus (CC) microbiota of broiler chickens were evaluated. The dietary treatments had no significant effects on the pattern of intestinal microbiota or production traits. The digestive tract bacteriota composition was affected mostly by the sampling place and age of birds. The dominant family of IC was Lactobacillaceae, without change with the age. The abundance of the two other major families, Enterococcaceae and Lachnospiraceae decreased with the age of birds. In the IM, Clostridiaceae was the main family in the first three weeks. Its ratio decreased later and Lactobacillaceae became the dominant family. In the CC, Ruminococcaceae and Lachnospiraceae were the main families with decreasing tendency in the age. In IC, Br treatment decreased the abundance of genus Lactobacillus, and both Br and Sy increased the ratio of Enterococcus at day 7. In all gut segments, a negative correlation was found between the IBD antibody titer levels and the ratio of genus Leuconostoc in the first three weeks, and a positive correlation was found in the case of Bifidobacterium, Rombutsia, and Turicibacter between day 21 and 40.

Role of Exposure to Lactic Acid Bacteria from Foods of Animal Origin in Human Health

Animal products, in particular dairy and fermented products, are major natural sources of lactic acid bacteria (LAB). These are known for their antimicrobial properties, as well as for their roles in organoleptic changes, antioxidant activity, nutrient digestibility, the release of peptides and polysaccharides, amino acid decarboxylation, and biogenic amine production and degradation. Due to their antimicrobial properties, LAB are used in humans and in animals, with beneficial effects, as probiotics or in the treatment of a variety of diseases. In livestock production, LAB contribute to animal performance, health, and productivity. In the food industry, LAB are applied as bioprotective and biopreservation agents, contributing to improve food safety and quality. However, some studies have described resistance to relevant antibiotics in LAB, with the concomitant risks associated with the transfer of antibiotic resistance genes to foodborne pathogens and their potential dissemination throughout the food chain and the environment. Here, we summarize the application of LAB in livestock and animal products, as well as the health impact of LAB in animal food products. In general, the beneficial effects of LAB on the human food chain seem to outweigh the potential risks associated with their consumption as part of animal and human diets. However, further studies and continuous monitorization efforts are needed to ensure their safe application in animal products and in the control of pathogenic microorganisms, preventing the possible risks associated with antibiotic resistance and, thus, protecting public health.

Multi-Strain Probiotics: Synergy among Isolates Enhances Biological Activities

The use of probiotics for health benefits is becoming popular because of the quest for safer products with protective and therapeutic effects against diseases and infectious agents. The emergence and spread of antimicrobial resistance among pathogens had prompted restrictions over the non-therapeutic use of antibiotics for prophylaxis and growth promotion, especially in animal husbandry. While single-strain probiotics are beneficial to health, multi-strain probiotics might be more helpful because of synergy and additive effects among the individual isolates. This article documents the mechanisms by which multi-strain probiotics exert their effects in managing infectious and non-infectious diseases, inhibiting antibiotic-resistant pathogens and health improvement. The administration of multi-strain probiotics was revealed to effectively alleviate bowel tract conditions, such as irritable bowel syndrome, inhibition of pathogens and modulation of the immune system and gut microbiota. Finally, while most of the current research focuses on comparing the effects of multi-strain and single-strain probiotics, there is a dearth of information on the molecular mechanisms of synergy among multi-strain probiotics isolates. This forms a basis for future research in the development of multi-strain probiotics for enhanced health benefits.

Probiotics (Direct-Fed Microbials) in Poultry Nutrition and Their Effects on Nutrient Utilization, Growth and Laying Performance, and Gut Health: A Systematic Review

Simple Summary

Probiotics are live bacteria, fungi, or yeasts that supplement the gastrointestinal flora and help to maintain a healthy digestive system, thereby promoting the growth performance and overall health of poultry. Probiotics are increasingly being included in poultry diets as an alternative to antibiotics. This systematic review provides a summary of the use of probiotics in poultry production and the potential role of probiotics in the nutrient utilization, growth and laying performance, and gut health of poultry.

Abstract

Probiotics are live microorganisms which, when administered in adequate amounts, confer health benefits to the host. The use of probiotics in poultry has increased steadily over the years due to higher demand for antibiotic-free poultry. The objective of this systematic review is to present and evaluate the effects of probiotics on the nutrient utilization, growth and laying performance, gut histomorphology, immunity, and gut microbiota of poultry. An electronic search was conducted using relevant keywords to include papers pertinent to the topic. Seventeen commonly used probiotic species were critically assessed for their roles in the performance and gut health of poultry under existing commercial production conditions. The results showed that probiotic supplementation could have the following effects: (1) modification of the intestinal microbiota, (2) stimulation of the immune system, (3) reduction in inflammatory reactions, (4) prevention of pathogen colonization, (5) enhancement of growth performance, (6) alteration of the ileal digestibility and total tract apparent digestibility coefficient, and (7) decrease in ammonia and urea excretion. Thus, probiotics can serve as a potential alternative to antibiotic growth promoters in poultry production. However, factors such as the intestinal health condition of birds, the probiotic inclusion level; and the incubation conditions, feedstuff, and water quality offered to birds may affect the outcome. This systematic review provides a summary of the use of probiotics in poultry production, as well as the potential role of probiotics in the nutrient utilization, growth and laying performance, and gut health of poultry.

Effects of in ovo feeding of N-acetyl-L-glutamate on early intestinal development and growth performance in broiler chickens

The present study determined the effects of in ovo feeding (IOF) of N-acetyl-L-glutamate (NAG) on early intestinal development and growth performance of broilers. A total of 702 fertile broiler eggs were randomly divided into 3 treatments: 1) non-punctured control group, 2) saline-injected control group, and 3) NAG solution-injected group (1.5 mg/egg). At 17.5 D of incubation, 300 μL of each solution was injected into each egg of injected groups. Results indicated that the hatchability and healthy chicken rate were not affected by NAG injection (P > 0.05). Chicks from NAG solution-injected group had significantly decreased average daily feed intake and feed conversion ratio during 1-14 D than those in the non-punctured control group (P < 0.05). Compared with the non-punctured control group, IOF of NAG significantly increased the density of goblet cells in jejunum at hatch, duodenum at 7 D, and ileum at 14 D; decreased crypt depth in jejunum at hatch; and increased villus height in duodenum and jejunum and villus height:crypt depth ratio in duodenum at 7 D (P < 0.05). The intestinal mRNA expression of Na⁺-dependent neutral amino acid transporter, peptide transporter, and excitatory amino acid transporter 3 did not differ between groups at 7 or 14 D. However, the mRNA expression level of rBAT in jejunum significantly increased in the NAG solution-injected group than in the non-punctured control group at 7 D (P < 0.05). In conclusion, IOF of NAG (1.5 mg/egg) accelerated the early intestinal development by enhancing intestinal immune and absorption function, thereby positively affecting the feed efficiency for the first 2 wk post-hatch.