Direct-Fed Microbial PrimaLac and Salinomycin Modulate Whole-Body and Intestinal Oxygen Consumption and Intestinal Mucosal Cytokine Production in the Broiler Chick

Effect of direct-fed microbials on growth performance, blood biochemical indices, and immune status of female goats

The effect of direct-feed microbial (DFM) treatment on body weight, serum biochemical indexes, serum immunoglobulins, and serum cytokines was studied. The study was a completely randomized design with 20 growing females Beichuan white goats, weighing 25.11 ± 1.96 kg, divided into two groups of 10 goats per treatment. Goats were offered (1) 10 mL saline solution (Control group) (2) or 10 mL microbials solution (DFM group) on days 0 and 7 for two times. No effect on final body weight and body size was observed between DFM and control group (p > 0.05). DFM treatment had greater serum total protein, globulin, and albumin/globulin ratio than the control treatment (p < 0.05). The concentrations of IgA, IgG, IgM, INF-γ, and IL-2 in DFM group were significantly higher than those in the control group on days 7, 14, and 21 (p < 0.05), and the highest content was detected on day 14 of the experiment. The concentrations of IgA, IgG, IgM, IL-2, INF-γ, INF-α, IL-4, and IL-5 in DFM group on day 14 were higher than those on day 0 (p < 0.05). In conclusion, DFM enhanced serum immunoglobulins and cytokines without affecting body weight, body size, and normal serum metabolism.

The effects of probiotic and threonine application on the carcass yield, internal organ development, intestinal morphology and cecal microbiota of broilers challenged with Clostridium perfringens

The aim of this study was to explore the effects of probiotics (Ecobiol®) and threonine supplements on broiler internal organs and intestinal health under Clostridium perfringens challenge. A total of 1600 male Ross 308 broiler chicks were randomly assigned to eight treatments with eight replicates each of 25 birds. Dietary treatments consisted of two levels of supplemented threonine (without and with threonine supplementation), two levels of probiotics (Ecobiol®) supplement (0 and 0. 1% of diet), and two levels of challenge (without and with 1 ml of the C. perfringens inoculum (∼10⁸ cfu/ml) on d 14, 15, and 16 of the experiment), which fed to the birds during a 42 d feeding trial. The results showed that adding threonine and probiotic supplements to the diets of C. perfringens-infected birds reduced the relative gizzard weight by 22.9% compared to those fed un-supplemented diet (P ≤ 0.024). As compared to the non-challenged group, the C. perfringens challenge significantly reduced the carcass yield of broilers by 1.18% (P < 0.0004). The groups receiving threonine and probiotic supplementation had higher carcass yield, and the inclusion of probiotics in the diet decreased abdominal fat by 16.18% compared with the control treatment (P ≤ 0.001). Adding threonine and probiotic supplements to the diets of broilers challenged with C. perfringens increased the jejunum villus height in comparison with C. perfringens-infected group fed an unsupplemented diet on day 18 (P ≤ 0.019). The number of cecal E. coli increased in birds under C. perfringens challenge in comparison with the negative group. Based on the findings, dietary inclusion of threonine and probiotic supplement could beneficially affect intestine health and carcass weight during the C. perfringens challenge.

Probiotics and gut health: linking gut homeostasis and poultry productivity

The use of probiotics in poultry production has increased rapidly, and this movement has been promoted by global events, such as the prohibition or decline in the use of antibiotic growth promotants in poultry feeds. There has been a persistent search for alternative feed additives, and probiotics have shown that they can restore the composition of the gut microbiota, and produce health benefits to the host, including improvements in performance. Probiotics have shown potential to increase productivity in poultry, especially in flocks challenged by stressors. However, the outcomes of probiotic use have not always been consistent. There is an increasing demand for well defined products that can be applied strategically, and currently, probiotic research is focusing on delineating their mechanisms of action in the gut that contribute to an improved efficacy. In particular, mechanisms involved in the maintenance and protection of intestinal barrier integrity and the role of the gut microbiota are being extensively investigated. It has been shown that probiotics modulate intestinal immune pathways both directly and through interactions with the gut microbiota. These interactions are key to maintaining gut homeostasis and function, and improving feed efficiency. Research has demonstrated that probiotics execute their effects through multiple mechanisms. The present review describes recent advances in probiotic use in poultry. It focuses on the current understanding of gut homeostasis and gut health in chickens, and how it can be assessed and improved through supplementation of poultry diets with probiotics in poultry diets. In particular, cellular and molecular mechanisms involved in the maintenance and protection of gut barrier structure and function are described. It also highlights important factors that influence probiotic efficacy and bird performance.

Effect of Lactobacillus Species Probiotics on Growth Performance of Dual-Purpose Chicken

Introduction

In-feed probiotics are becoming attractive alternatives to antibiotics in the poultry industry due to the ever-growing strict prohibitions on antibiotic growth promoters (AGP) in animal production.

Methods

The study was conducted to investigate the effects of Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus on the growth performance of 120 day-olds randomly selected Sasso dual-purpose chicken. They were divided into four groups with two replicates per group and 15 chicks per replicate. The treatments were T₁ (control), T₂ (supplement diet with 4g probiotic), T₃ (supplement diet with 2g probiotic), T₄ (supplement diet with 1g probiotic). The experimental feeding trials were conducted after two weeks adaptation period.

Results

The present findings revealed that the chickens supplemented with Lactobacillus species probiotics during the first week of age have shown higher body weight than control (p < 0.05). The feed intake of week one of T₂ and T₃ were significantly higher (p< 0.05) than the T₁ (control). However, there was no significant difference (p> 0.05) in feed intake in the 2^nd, 3^rd, 4^th, and 5^{t h} weeks of all treatment groups. The present result showed that there was a significant body weight gain (p< 0.05) in all probiotic fed groups than the control group. The highest body weight gain was observed in chickens found in the T4 treatment group. Whereas the body weight gains significantly higher and improved the feed conversion (p<0.05) in the T₂ and T₄ than the T₁ (control). However, the feed conversion ratio was significantly influenced by probiotic inclusion in T₃ as compared to the control group.

Conclusion

Overall, the results suggest that Lactobacillus paracaseis sparacasei and Lactobacillus rhamnosus have a positive effect on the growth performance of broilers.

Dietary inclusion of multispecies probiotics to reduce the severity of post-weaning diarrhea caused by Escherichia coli F18+ in pigs

This study was aimed to determine the efficacy of multispecies probiotics in reducing the severity of post-weaning diarrhea caused by enterotoxigenic Escherichia coli (ETEC) F18⁺ on newly weaned pigs. Thirty-two pigs (16 barrows and 16 gilts, BW = 6.99 ± 0.33 kg) at 21 d of age were individually allotted in a randomized complete block design with 2 × 2 factorial arrangement of treatments. Pigs were selected from sows not infected previously and not vaccinated against ETEC. Pigs were fed experimental diets for 25 d based on 10 d phase 1 and 15 d phase 2. The factors were ETEC challenge (oral inoculation of saline solution or E. coli F18⁺ at 2 × 10⁹ CFU) and probiotics (none or multispecies probiotics 0.15% and 0.10% for phase 1 and 2, respectively). Body weight and feed intake were measured on d 5, 9, 13, 19, and 25. Fecal scores were measured daily. Blood samples were taken on d 19 and 24. On d 25, all pigs were euthanized to obtain samples of digesta, intestinal tissues, and spleen. The tumor necrosis factor alpha (TNFα), malondialdehyde (MDA), peptide YY (PYY), and neuropeptide Y (NPY) were measured in serum and intestinal tissue. Data were analyzed using the MIXED procedure of SAS. The fecal score of pigs was increased (P < 0.05) by ETEC challenge at the post–challenge period. The ETEC challenge decreased (P < 0.05) jejunal villus height and crypt depth, tended to increase (P = 0.056) jejunal TNFα, increased (P < 0.05) ileal crypt depth, and decreased (P < 0.05) serum NPY. The probiotics decreased (P < 0.05) serum TNFα, tended to reduce (P = 0.064) jejunal MDA, tended to increase (P = 0.092) serum PYY, and increased (P < 0.05) jejunal villus height, and especially villus height-to-crypt depth ratio in challenged pigs. Growth performance of pigs were not affected by ETEC challenge, whereas the probiotics increased (P < 0.05) ADG and ADFI and tended to increase (P = 0.069) G:F ratio. In conclusion, ETEC F18⁺ challenge caused diarrhea, intestinal inflammation and morphological damages without affecting the growth performance. The multispecies probiotics enhanced growth performance by reducing intestinal inflammation, oxidative stress, morphological damages.

Effect of the Use of Yarrowia lipolytica or Saccharomyces cerevisiae Yeast with a Probiotic in the Diet of Turkey Hens on Growth Performance and Gut Histology

The aim of the study was to determine whether the alternative yeast species Yarrowia lipolytica in turkey feed would have a more beneficial effect on growth performance and intestinal histology than the commonly used species Saccharomyces cerevisiae. An additional objective of the study was to test whether the addition of a probiotic to feed containing Yarrowia lipolytica or Saccharomyces cerevisiae yeast would enhance its effect on growth performance and intestinal histology in turkeys. The experiment was carried out on 480 turkey hens randomly divided into six groups. Birds from the control group (C) and group P were fed standard feeds but group P additionally received a probiotic (0.05%). Groups Y and YP received feed containing Yarrowia lipolytica fodder yeast (3%), and the YP group received also the probiotic (0.05%). Similarly, in groups S and SP, the turkeys received feed with Saccharomyces cerevisiae fodder yeast (3%), and for the SP group the probiotic was added to the feed (0.05%). Yarrowia lipolytica yeast added in the amount of 3% to the turkey feed may be an alternative to the commonly used Saccharomyces cerevisiae yeast, because it improved growth performance, and above all, had a more beneficial effect on intestinal histology. The use of Yarrowia lipolytica alone can be beneficial for growth performance, while the combined use of 3% Yarrowia lipolytica in the feed and a 0.05% addition of a probiotic containing Bacillus licheniformis and Bacillus subtilis has a more beneficial effect on gastrointestinal histology.

Effect of dietary supplementation of prebiotic on growth performance, immune response and intestinal microbial load in broiler chickens

The experiment was conducted to study the effect of using prebiotic (mannan oligosachharide -MOS) in place of antibiotic growth promoter (AGP) on performance, immune response and intestinal microbial load in broiler chickens. Day-old broiler chicks (192) were randomly distributed into 20 groups each of 8 chicks (4 treatments × 6 replicates). Four experimental diets T1, T2, T3 and T4 were formulated to contain no additive, bacitracin methylene di-salicylate (BMD) at 20 mg/kg diet, MOS at 0.1 and 0.2%, respectively. Body weight gain (g) was increased by the feeding of diets containing 0.2% levels of MOS, but feed intake (g), feed conversion ratio (FCR) and mortality (%) did not differ significantly. Antibody (28 d), titres were significantly higher after feeding 0.1 or 0.2% MOS and antibiotic (T2) supplemented group. During d 35, the response to intra-dermally injected phyto-hemagglutinin, an index of the in vivo cell-mediated immune response, was increased in the 0.2% MOS supplemented group. Significant reduction was observed in coliforms and total plate count in cecal (28 and 42 d) and excreta (42 d) in MOS (0.1 or 0.2%) or antibiotic (T2) supplemented groups. Lactobacillus count significantly increased in cecal (28 and 42 d) and excreta (42 d) in MOS @0.1 or 0.2% supplemented groups. Thus, it can be concluded that, 0.2% MOS with basal diet has a beneficial effect for growth performance, immune response and gut health status in broiler chickens, and MOS could be a good alternative to antibiotic growth promoter.

Effects of a blend of Saccharomyces cerevisiae-based direct-fed microbial and fermentation products in the diet of newly weaned beef steers: growth performance, whole-blood immune gene expression, serum biochemistry, and plasma metabolome1

We examined the effects of dietary supplementation of a Saccharomyces cerevisiae-based direct-fed microbial (DFM) on the growth performance, whole-blood immune gene expression, serum biochemistry, and plasma metabolome of newly weaned beef steers during a 42 d receiving period. Forty newly weaned Angus crossbred steers (7 d post-weaning; 210 ± 12 kg of BW; 180 ± 17 d of age) from a single source were stratified by BW and randomly assigned to 1 of 2 treatments: basal diet with no additive (CON; n = 20) or a basal diet top-dressed with 19 g of the DFM (PROB; n = 20). Daily DMI and weekly body weights were measured to calculate average daily gain (ADG) and feed efficiency (FE). Expression of 84 immune-related genes was analyzed on blood samples collected on days 21 and 42. Serum biochemical parameters and plasma metabolome were analyzed on days 0, 21, and 42. On day 40, fecal grab samples were collected for pH measurement. Compared with CON, dietary supplementation of PROB increased final body weight (P = 0.01) and ADG (1.42 vs. 1.23 kg; P = 0.04) over the 42 d feeding trial. There was a tendency for improved FE with PROB supplementation (P = 0.10). No treatment effect (P = 0.24) on DMI was observed. Supplementation with PROB increased (P ≤ 0.05) the concentrations of serum calcium, total protein, and albumin. Compared with CON, dietary supplementation with PROB increased (P ≤ 0.05) the expression of some immune-related genes involved in detecting pathogen-associated molecular patterns (such as TLR1, TLR2, and TLR6), T-cell differentiation (such as STAT6, ICAM1, RORC, TBX21, and CXCR3) and others such as TNF and CASP1, on day 21 and/or day 42. Conversely, IL-8 was upregulated (P = 0.01) in beef steers fed CON diet on day 21. Plasma untargeted plasma metabolome analysis revealed an increase (P ≤ 0.05) in the concentration of metabolites, 5-methylcytosine and indoleacrylic acid involved in protecting the animals against inflammation in steers fed PROB diet. There was a tendency for lower fecal pH in steers fed PROB diet (P = 0.08), a possible indication of increased hindgut fermentation. This study demonstrated that supplementation of PROB diet improved the performance, nutritional status, and health of newly weaned beef steers during a 42 d receiving period.

Effects of Lactococcus lactis MG1363 producing fusion proteins of bovine lactoferricin-lactoferrampin on growth, intestinal morphology and immune function in weaned piglet

AIMS

We developed a strategy for localized delivery of the LFCA (lactoferricinlactoferrampin), which is actively synthesized in situ by Lactococcus lactis (pAMJ399-LFCA/LLMG1363), and explored the possibility of using pAMJ399-LFCA/LLMG1363 as an alternative additive diet to antibiotics.

METHODS AND RESULTS

The antimicrobial activities of the LFCA derived from pAMJ399-LFCA/LLMG1363 were tested in vitro. The results showed that LFCA had an inhibitory effect on Staphylococcus aureus, Escherichia coli and Salmonella enteritidis. Then, the pAMJ399-LFCA/LLMG1363 was used as an additive diet for piglets. Our data demonstrated that oral administration of pAMJ399-LFCA/LLMG1363 significantly improved the average daily gain, feed-to-gain ratio, intestinal mucosal integrity and decreased the serum endotoxin and d-lactic acid levels. The mRNA expression levels of intestinal tight junction proteins (including occludin, Claudin-1 and ZO-1) were significantly upregulated by pAMJ399-LFCA/LLMG1363 administration. The serum immunoglobulin G (IgG) levels, intestinal secretory immunoglobulin A (sIgA) levels, IL-2, IL-10 and TGF-β levels were significantly increased by pAMJ399-LFCA/LLMG1363. Furthermore, our data revealed that oral administration of pAMJ399-LFCA/LLMG1363 significantly increased the number of general Lactobacillus, and decreased the total viable E. coli counts in the ileum and cecum contents.

CONCLUSIONS

We developed a novel pAMJ399-LFCA/LLMG1363 secreting LFCA, which had probiotic effects on the growth performance, intestinal morphology, intestinal barrier function and immunological indices of weaned piglets.

SIGNIFICANCE AND IMPACT OF THE STUDY

pAMJ399-LFCA/LLMG1363, with probiotic effects on the health of weaned piglets, may be a promising feed additive for weaned piglets.

Potency of probiotics Bifidobacterium spp. and Lactobacillus casei to improve growth performance and business analysis in organic laying hens

Aim:

This study aimed to determine the use of probiotics Bifidobacterium spp. and Lactobacillus casei as alternative antibiotic growth promoters (AGPs) to improve growth performance and business analysis.

Materials and Methods:

This study used a completely randomized factorial design. The first factor was the time of administration (1, 2, 3, and 4 weeks) and the second was the use of probiotics (control without probiotics; 0.1% AGP and 0.5% Bifidobacterium spp. + 0.25% L. casei). One hundred and eighty laying hens (Lohmann strain), of 30 weeks old, were divided into 12 treatment groups, composed of five replicates, each consisting of three laying hens.

Results:

The results showed that using 0.5% Bifidobacterium spp. + 0.25% L. casei in weeks 1 and 2 showed the lowest feed intake (FI) (112.11-112.19 g/day), the highest egg weight (60.28 g) in the 1^st week, the lowest feed conversion ratio (FCR) (2.21-2.23), and highest feed efficiency (44.75-45.25%) for 3-4 weeks, and the highest hen-day production (86.66-86.90%) for 3-4 weeks and the most profitable business analysis (IDR. 30,353).

Conclusions:

Based on the results, it can be concluded that the addition of 0.5% Bifidobacterium spp. + 25% L. casei probiotics can be used as a substitute for AGP; it can reduce the FI and FCR, increasing egg weight, feed efficiency, and hen-day production, as well as illustrating the results of the most profitable business analysis.

Effects of Enterococcus faecalis on egg production, egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with Enterococcus faecalis (EF) on egg production, egg quality and caecal microbiota. A total of 360 Hy-Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 3.75 · 10⁸ cfu EF/kg (Group I) or the basal diet + 7.5 · 10⁸ cfu EF/kg (Group II). The experiment lasted for 45 d. Eggs and caecal samples were collected at the end of the experiment. Results showed that dietary supplementation with EF did not affect the average daily egg weight, cracked egg rate, mortality and egg quality. However, EF supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p < 0.05). The differences in caecal microbiota between Group II and the Control were significant. The relative abundance of Verrucomicrobia and Cyanobacteria at the phylum level, Rikenellaceae, Christensenellaceae and Veillonellaceae at the family level, and the Faecalibacterium, Christensenellaceae R-7 group and Eubacterium coprostanoligenes group at the genus level changed significantly in Group II compared with the Control (p < 0.05). In conclusion, the tested dietary supplementations with EF improved product performance and affected the caecal microbial community structure of laying hens during the late laying period.

16S ribosomal RNA sequencing reveals a modulation of intestinal microbiome and immune response by dietary L-theanine supplementation in broiler chickens

Despite the availability of abundant literature on green tea, studies on the use of L-theanine (an amino acid found only in green tea) as a feed additive in poultry especially broiler are limited. So, this study was conducted to explore the effects of L-theanine on the intestinal microbiome and immune response in a broiler. A total of 400-d-old chicks were randomly divided into four treatment groups (A, B, C, and D) using a complete randomized design. Treatments were as follows: A, control (basal diet); B, basal diet + 100 mg L-theanine/kg diet; C, basal diet + 200 mg L-theanine/kg diet; and D, basal diet + 300 mg L-theanine/kg diet. Mucosal samples from ileum and jejunum of broiler chicken were extracted at 21 and 42 d of age. Extraction of genomic DNA was followed by amplification of V3 and V4 hypervariable regions of 16S ribosomal RNA. After Illumina sequencing, results revealed that treatment with L-theanine significantly increased the population of Lactobacillus in ileum and jejunum as compared to a control group, but the higher population was observed in jejunum at both 21 and 42 d of age. The overall diversity of the jejunum microbiome in the treatment group was significantly lower than that of the ileum and control group (P < 0.05). Results of this study revealed that mRNA expression of TLRs (TLR-2 and TLR-4) and cytokines (TNF-α, IFN-γ, and IL-2) was decreased in response to treatment with L-theanine. Moreover, the negative correlation of abundance of Lactobacillus was observed with expression of IL-2 and IFN-γ in the intestine and these effects were highly significant (P < 0.01). In summary, our finding revealed that dietary supplementation of L-theanine exhibited a positive influence on intestinal bacteria by supporting beneficial microbes like Lactobacillus while decreasing harmful microbes like Clostridium.

Comparison of single- and multi-strain probiotics effects on broiler breeder performance, egg production, egg quality and hatchability

1. This study was conducted to investigate the effect of multi-strain probiotic (containing Lactobacillus acidophilus 2.5 × 10⁷ cfu/g, Lactobacillus casei 2.5 × 10⁷ cfu/g, Bifidobacterium thermophilum 2.5 × 10⁷ cfu/g and Enterococcus faecium 2.5 × 10⁷ cfu/g) and single-strain probiotic (Pediococcus acidilactici 1 × 10¹⁰ cfu/g) on broiler breeder performance and gastrointestinal health. 2. A completely randomised trial was conducted using 300 broiler breeder hens (Ross 308) aged 51 weeks old which were randomly allocated to 1 of 5 dietary treatments with 6 replicates per treatment in a 10 week trial. Treatments included (1) the basal diet a negative control, (2) basal diet supplemented with 0.1 g/kg multi-strain probiotic (MS), (3) basal diet supplemented with 0.1 g/kg single-strain probiotic (SS), (4) basal diet supplemented with 0.1 g/kg of both of probiotics (MS+ SS) and (5) positive control basal diet supplemented with 0.5 g/kg oxytetracycline antibiotic (OX). 3. Body weight, egg production, yolk weight, eggshell thickness and weight, Haugh unit, fertility and hatchability were determined. Results showed that dietary treatments had no significant effect on total hen house or total hatching egg production, egg weight, yolk colour index, shell weight, mortality, body weight, fertility, hatchability, oviduct and stroma weight or number of large and small yellow follicles (P > 0.05). None of the jejunum morphological parameters, apparent ileal digestibility of protein and ileal Lactobacillus population were influenced by supplemental probiotics (P > 0.05), although ileum Escherichia coli count was reduced by inclusion of dietary probiotics (P < 0.05). 4. It was concluded that although both probiotic treatments reduced coliforms, they did not improve broiler breeder performance or gastrointestinal tract (GIT) function.

Effect of in ovo injection of raffinose on growth performance and gut health parameters of broiler chicken

The effects of in ovo injection of raffinose (RFO) as a prebiotic on growth performance, relative weight of proventriculus, gizzard, drumstick and breast muscles, and ileum mucosa morphology were examined in Cobb 500 broilers. A total of 240 fertilized eggs were divided into 4 groups: a non-injected with intact shell and 3 levels of RFO solution (1.5, 3.0, and 4.5 mg in 0.2 mL of an aqueous diluents). The RFO solution was injected into the air sac on d 12 of incubation. In total 144 birds were fed a standard diet and management and sacrificed at d 21 post hatch for collection of samples. Total RNA was extracted from the small intestine, and RT-qPCR was performed to quantify mRNA levels of marker genes of immune cells. Injection of RFO had no significant effect (P > 0.05) on d one body weight of chicks. On d 21, the relative weight of the proventriculus, drumstick, breast, and gizzard was not affected (P > 0.05) by RFO. On hatch d, the villus height increased linearly (P < 0.01) with an increasing dose of RFO. Also, an increasing dose of RFO increased the villus height and villus height:crypt depth ratio (P < 0.05) but did not affect the crypt depth on d 21. The expression levels of CD3 and chB6, which are T cell and B cell marker genes, respectively, were significantly enhanced by high dose RFO (4.5 mg). In conclusion, although an increasing dose of RFO in ovo injection did not significantly influence growth performance or slaughter yield of broilers, RFO has the potential of enhancing ileum mucosa morphology and improving immunity in the small intestine, which are indicators of improved gut health.

Enrofloxacin and Probiotic Lactobacilli Influence PepT1 and LEAP-2 mRNA Expression in Poultry

Expression of peptide transporter 1 (PepT1) and liver-expressed antimicrobial peptide 2 (LEAP-2) in chickens can be influenced by food deprivation, pathological conditions and drug administration. Effect of three putative probiotic Lactobacillus strains and enrofloxacin on the expression of PepT1 and LEAP-2 mRNA was investigated in Ross 308 chickens. One-day-old chicks (n = 24) were allocated to following groups: control (without treatment); group treated with probiotics via feed; group treated with a combination of probiotics and enrofloxacin; and a group given enrofloxacin only. The drug was administered at a dose of 10 mg kg^-1, via drinking water for 5 days. Samples from liver, duodenum and jejunum were collected 126 h after the start of the treatment. Expression levels of PepT1 and LEAP-2 were determined by real-time polymerase chain reaction and were statistically evaluated by Mann-Whitney test. Enrofloxacin administered alone or in combination with probiotics provoked a statistically significant up-regulation of PepT1 mRNA levels in the measured organ sites. These changes can be attributed to a tendency of improvement in utilization of dietary peptide and in body weight gain. LEAP-2 mRNA expression levels did not change significantly in enrofloxacin-treated chickens in comparison with control group.

Studies on the growth performance of different broiler strains at high altitude and evaluation of probiotic effect on their survivability

Identification of appropriate breeds of broilers and development of new feed additives is required for the development of poultry industry at high altitude. Therefore, this experiment was conducted first to identify the suitable broiler strain for this region. One week old chicks (150) from three broiler strains, i.e. Vencobb, RIR cross-bred, and Hubbard were randomly selected and divided equally into three groups. All the chicks were provided the same basal diet. The body weight gain and feed: gain responses were significantly (P < 0.05) improved in RIR cross-bred. Mortality was also observed lower in RIR cross-bred. Thereafter, the second trial was conducted in RIR cross-bred to evaluate the effect of probiotic supplementation (T1@ 9 gm/kg feed, T2@ 18 gm/kg feed) on their performance and mortality. No significant differences (P > 0.05) were observed in weight gain, feed intake, feed: gain, and water intake among the three groups, however, mortality from ascites and coccidiosis was reduced in probiotic treated groups. Hence, our results suggest that RIR cross-bred is suitable for rearing in high altitude regions and probiotic supplementation has no beneficial effects on production performance of broilers at high altitude. However, probiotic supplementation indicated lesser loss due to mortality of birds.

Effects of two different probiotics on microflora, morphology, and morphometry of gut in organic laying hens

The current study investigated the effects of Lactobacillus acidophilus and Bacillus subtilis, used as probiotics, on the microflora, morphology, and morphometry of the gut in organic laying hens. The birds (180 Hy-Line laying hens) were divided into 3 homogenous groups and received a pre-deposition diet from 16 to 20 wk of age and a deposition diet for the remaining 7 months of the experiment. The control group ( CTR: ) was fed a corn-soybean cake-based diet, the second group ( L: ) received the same diet supplemented with 0.1% of L. acidophilus while in the third group ( B: ) the basal diet was supplemented with 0.05% of B. subtilis At 18 wk of age ( T1: ) and at 5 ( T2: ) and 7 months ( T3: ) from the beginning of deposition, 9 subjects per group were humanely killed for microbiological, morphological and morphometric analyses of the intestinal tract. The 2 probiotic-supplemented diets increased Lactobacillus spp. and Bifidobacterium spp. counts compared with the CTR diet. The lowest viable counts of E. coli, coliforms and staphylococci were observed in the L group (P < 0.001). Clostridium spp. decreased (P < 0.001) in both L and B subjects. The probiotic supplementation appeared to affect the intestinal microbial population, promoting the presence of beneficial bacteria such as Lactobacillus spp. and Bifidobacterium spp. and reducing potential harmful bacteria such as E. coli, clostridia and staphylococci. Morphological and morphometric analyses did not reveal substantial differences among groups. At T3, the plasma cell infiltrate in the villi of the CTR hens was more severe than that observed in the L and B groups (P = 0.009).

Effect of a potential probiotics Lactococcus garvieae B301 on the growth performance, immune parameters and caecum microflora of broiler chickens

In this study, a novel Lactococcus garvieae B301 was isolated from the intestinal tract of a healthy piglet. L. garvieae B301 was tolerant to acid pH, simulated gastric and small intestinal transit juices, indicating that it was capable of surviving in the gastrointestinal tract. L. garvieae B301 was safe and beneficial to broilers, as broiler chickens supplemented with L. garvieae B301 had lower diarrhoea incidence and mortality than the Control. Moreover, supplementation of broiler diets with L. garvieae B301 resulted in an increase in body weight and the number of caecum lactic acid bacteria and Bifidobacterium spp., and decrease in feed-to-gain ratio and the number of caecum coliforms. It also had a positive effect on the thymus index and bursa of Fabricius index and enhanced serum levels of immune globulins. All these results showed that L. garvieae B301 could enhance the growth performance of broiler chickens and improve their health. Thus, L. garvieae B301 could be a promising feed additive for broiler chickens.

Effect of direct-fed microbials on utilization of degradable intake protein in receiving steers

Kenney, N. M., Vanzant, E. S., Harmon, D. L. and McLeod, K. R. 2015. Effect of direct-fed microbials on utilization of degradable intake protein in receiving steers. Can. J. Anim. Sci. 95: 93–102. One hundred ninety-two crossbred beef steers (280±25 kg) were assigned to a 5×2 factorial; degradable intake protein (DIP; 80, 90, 100, 110, 120% of requirement) with and without a direct-fed microbial (DFM) primarily containing Lactobacillus acidophilus and Enterococcus faecium (109CFU steer−1d−1). Dry matter intake, morbidity, and immune response were not affected (P≥0.11). The first 28 d, average daily gain (ADG) did not differ with DIP in control, but increased in a cubic fashion with DFM (DIP×DFM; P=0.05). No differences (P≥0.25) in ADG occurred from days 29 to 56; however, there was a tendency (P=0.08) for a cubic increase in ADG with increasing DIP with DFM over 56 d. The first 28 d, growth efficiency did not differ across DIP levels in control but increased linearly with DFM (DIP×DFM; P=0.05). No differences (P≥0.21) in efficiency were observed from days 29 to 56 or overall. Without DFM, fecal pH decreased between days 7 and 14; however, with DFM there was no change in pH (DFM×time; P<0.05). Performance response to DFM is dependent on DIP; however, DFM does not impact morbidity or humoral immune response.

Evaluation of the efficacy of sequential or continuous administration of probiotics and phytogenics in broiler diets

Three dietary combinations of probiotics and phytogenics administered sequentially or continuously were assessed for their effects on broiler performance, nutrient digestibility, caecal microbiota composition, volatile fatty acid (VFA) pattern and plasma total antioxidant capacity (TAC). One-day-old Cobb male broilers (n = 525) were allocated to five experimental treatments for 42 days. Each treatment had three replicates of 35 broilers each. Depending on the time-frame of sequential or continuous addition in the basal diet (BD) of the probiotics (108 CFU/kg BD) and phytogenics (125 mg/kg BD), experimental treatments were: control (no additions, Days 1–42); PE1, probiotic Days 1–14 and phytogenic Days 15–42; PE2, probiotic Days 1–28 and phytogenic Days 29–42; PE3, probiotic and phytogenic continuously (Days 1–42); and A (2.5 mg avilamycin/kg diet, Days 1–42). There was no loss of probiotic viability upon mixing with the phytogenic for up to 7 days. Overall bodyweight gain was higher (P = 0.025) in the control and PE1 than PE2 and PE3, whereas Treatment A was intermediate and not different from the rest. Overall feed intake in the control was the highest (P = 0.003). Treatments PE1, PE2 and PE3 had better (P = 0.004) overall feed conversion ratio (FCR) than the control. The FCR in PE1 and PE3 did not differ from A, which had the best FCR. Mortality did not differ among treatments. Nutrient digestibility and caecal microbiota composition did not differ among treatments. However, differences (P ≤ 0.05) in caecal VFA pattern were noted, with the control having the lowest acetate molar ratio as well as the highest sum of valeric, hexanoic and heptanoic acids. Plasma TAC in the control was lower than in PE3, PE1 and PE2 at Day 14 (P < 0.001) and PE1 (P = 0.003) at Day 42. The concept of sequential or throughout probiotic and phytogenic administration showed promising results regarding feed efficiency and plasma TAC.

Effect of dietary antimicrobials on immune status in broiler chickens

This study evaluated the effects of dietary anticoccidial drugs plus antibiotic growth promoters (AGPs) on parameters of immunity in commercial broiler chickens. Day-old chicks were raised on used litter from a farm with endemic gangrenous dermatitis to simulate natural pathogen exposure and provided with diets containing decoquinate (DECX) or monensin (COBN) as anticoccidials plus bacitracin methylene disalicylate and roxarsone as AGPs. As a negative control, the chickens were fed with a non-supplemented diet. Immune parameters examined were concanavalin A (ConA)-stimulated spleen cell proliferation, intestine intraepithelial lymphocyte (IEL) and spleen cell subpopulations, and cytokine/chemokine mRNA levels in IELs and spleen cells. ConA-induced proliferation was decreased at 14 d post-hatch in DECX-treated chickens, and increased at 25 and 43 d in COBN-treated animals, compared with untreated controls. In DECX-treated birds, increased percentages of MHC2(+) and CD4(+) IELS were detected at 14 d, but decreased percentages of these cells were seen at 43 d, compared with untreated controls, while increased TCR2(+) IELs were evident at the latter time. Dietary COBN was associated with decreased fractions of MHC2(+) and CD4(+) IELs and reduced percentages of MHC2(+), BU1(+), and TCR1(+) spleen cells compared with controls. The levels of transcripts for interleukin-4 (IL-4), IL-6, IL-17F, IL-13, CXCLi2, interferon-γ (IFN-γ), and transforming growth factorβ4 were elevated in IELs, and those for IL-13, IL-17D, CXCLi2, and IFN-γ were increased in spleen cells, of DECX- and/or COBN-treated chickens compared with untreated controls. By contrast, IL-2 and IL-12 mRNAs in IELs, and IL-4, IL-12, and IL-17F transcripts in spleen cells, were decreased in DECX- and/or COBN-treated chickens compared with controls. These results suggest that DECX or COBN, in combination with bacitracin and roxarsone, modulate the development of the chicken post-hatch immune system.

Effects of multistrain probiotics on growth performance, apparent ileal nutrient digestibility, blood characteristics, cecal microbial shedding, and excreta odor contents in broilers

This experiment was conducted to investigate the efficacy of Lactobacillus acidophilus, Bacillus subtilis, and Clostridium butyricum supplementation in broilers. A total of 400 one-day-old mixed sex Ross 308 broilers with an initial average BW of 46 ± 0.5 g were randomly allotted into 4 treatments with 5 replicate pens per treatment and 20 broilers in each pen for 35 d. Dietary treatments were (1) an antibiotic-free diet (CON), (2) CON + 5 mg/kg of avilamycin, (3) CON + 1 × 10(5) cfu of multistrain probiotics/kg of diet (P1), and (4) CON + 2 × 10(5) cfu of multistrain probiotics/kg of diet (P2). Broilers fed the P1 and P2 diets had greater BW gain than broilers fed the CON diet during d 22 to 35 (P = 0.01) and overall (P = 0.02). Feed conversion ratios in P1 and P2 were decreased (P = 0.03) compared with that in CON from d 22 to 35. Ileal digestibility of most essential amino acids, with the exception of His and Phe, were increased (P < 0.05) in P1 and P2 compared with CON. Serum IgA and IgM concentrations in P2 were higher (P < 0.05) than those in CON. The cecal Lactobacillus numbers were increased (P = 0.02), and the counts of Escherichia coli were decreased (P = 0.03) in P1 and P2 compared with CON. Dietary supplementation with multistrain probiotics decreased (P < 0.05) the excreta NH3 content compared with the CON. In conclusion, dietary supplementation with multistrain probiotics improved broiler growth performance, ileal amino acids digestibility, and humoral immunity. Furthermore, the probiotics decreased the cecal numbers of E. coli and decreased the NH3 content of excreta.

Direct fed microbial supplementation repartitions host energy to the immune system

Direct fed microbials and probiotics are used to promote health in livestock and poultry; however, their mechanism of action is still poorly understood. We previously reported that direct fed microbial supplementation in young broilers reduced ileal respiration without changing whole-body energy expenditure. The current studies were conducted to further investigate the effects of a direct fed microbial on energy metabolism in different tissues of broilers. One hundred ninety-two 1-d-old broiler chicks (16 chicks/pen) were randomly assigned to 2 dietary groups: standard control starter diet (CSD) and CSD plus direct fed microbial (DFMD; 0.3%) with 6 pens/treatment. Body weight, feed consumption, whole-body energy expenditure, organ mass, tissue respiration rates, and peripheral blood mononuclear cell (PBMC) ATP concentrations were measured to estimate changes in energy metabolism. No differences in whole body energy expenditure or BW gain were observed; however, decreased ileal O(2) respiration (P < 0.05) was measured in DFMD fed broilers. In contrast, the respiration rate of the thymus in those broilers was increased (P < 0.05). The PBMC from DFMD fed broilers had increased ATP concentrations and exhibited increased ATP turnover (P < 0.01). To determine if the increased energy consumption by PBMC corresponded with an altered immune response, broilers were immunized with sheep red blood cells (SRBC) and assayed for differences in their humoral response. The DFMD-fed broilers had a faster rate of antigen specific IgG production (P < 0.05) and an increase in total IgA (P < 0.05). Collectively, these data indicate that supplementation with the direct fed microbial used in this study resulted in energy re-partitioning to the immune system and an increase in antibody production independent of changes in whole body metabolism or growth performance.

Effects of anticoccidial and antibiotic growth promoter programs on broiler performance and immune status

This study investigated the effects of various coccidiosis control programs in combination with antibiotic growth promoters (AGPs) on growth performance and host immune responses in broiler chickens. The coccidiosis programs that were investigated included in ovo coccidiosis vaccination (CVAC) with Inovocox or in-feed medication with diclazuril as Clinacox (CLIN) or salinomycin (SAL). The AGPs were virginiamycin or bacitracin methylene disalicylate plus roxarsone. As a negative control, chickens were non-vaccinated and fed with non-supplemented diets (NONE). All animals were exposed to used litter from a commercial broiler farm with confirmed contamination by Eimeria parasites to simulate in-field exposure to avian coccidiosis. Broiler body weights in the CVAC group were greater at 14 and 32 days of age, but not at day 42, compared with the NONE, CLIN, and SAL groups. At day 14, the SAL group showed decreased body weight and reduced ConA-stimulated spleen cell proliferation compared with the CLIN and SAL groups. In contrast, at days 34 and 43, splenocyte proliferation was greater in the CVAC and CLIN groups compared with the NONE and SAL groups. Lymphocyte subpopulations and cytokine mRNA expression levels in the intestine and spleen were also altered by the denoted treatments. Collectively, these results suggest that in ovo coccidiosis vaccination or coccidiostat drug medication programs in combination with AGPs influences chicken growth and immune status in an Eimeria-contaminated environment.

Effects of dietary lipids and Clostridium butyricum on the performance and the digestive tract of broiler chickens

The effects of two sources of dietary lipids and supplementation of Clostridium butyricum on performance and intestinal metabolism of broilers were investigated. In a 2 x 2 factorial arrangement, 168 one-day-old broiler chicks were divided into four treatment groups, and fed four diets with two lipid sources (soya bean oil or fish oil, at 25 g/kg and 30 g/kg in starter and grower diets respectively), and without or with supplementation of C. butyricum (1 x 10(9) colony forming units per kg diet). C. butyricum had no effect on broiler performance. At 20 and 40 d of age, the pH of caecal digesta and the relative length of caecum were decreased after supplementation of C. butyricum (p < 0.05). After this treatment, the activity of alkaline phosphatase was increased in jejunal mucosa at 40 d of age (p < 0.01). Furthermore, there were increases in populations of lactic acid bacteria and the concentrations of acetic acid, n-butyric acid, n-valeric acid and total short chain fatty acids in caecal digesta of birds fed C. butyricum (p < 0.05). A significant interaction between lipid source and C. butyricum was found in the pH of caecal digesta at 20 d of age (p < 0.01). The results of the present study indicated that dietary supplementation of C. butyricum maybe a benefit for gut health of broiler chickens.

Review: The use of direct fed microbials to mitigate pathogens and enhance production in cattle

McAllister, T. A., Beauchemin, K. A., Alazzeh, A. Y., Baah, J., Teather, R. M. and Stanford, K. 2011. Review: The use of direct fed microbials to mitigate pathogens and enhance production in cattle. Can. J. Anim. Sci. 91: 193–211. Direct-fed microbials (DFM) have been employed in ruminant production for over 30 yr. Originally, DFM were used primarily in young ruminants to accelerate establishment of the intestinal microflora involved in feed digestion and to promote gut health. Further advancements led to more sophisticated mixtures of DFM that are targeted at improving fiber digestion and preventing ruminal acidosis in mature cattle. Through these outcomes on fiber digestion/rumen health, second-generation DFM have also resulted in improvements in milk yield, growth and feed efficiency of cattle, but results have been inconsistent. More recently, there has been an emphasis on the development of DFM that exhibit activity in cattle against potentially zoonotic pathogens such as Escherichia coli O157:H7, Salmonella spp. and Staphylococcus aureus. Regulatory requirements have limited the microbial species within DFM products to organisms that are generally recognized as safe, such as lactic acid-producing bacteria (e.g., Lactobacillus and Enterococcus spp.), fungi (e.g., Aspergillus oryzae), or yeast (e.g., Saccharomyces cerevisiae). Direct-fed microbials of rumen origin, involving lactate-utilizing species (e.g., Megasphaera elsdenii, Selenomonas ruminantium, Propionibacterium spp.) and plant cell wall-degrading isolates of Butyrivibrio fibrisolvens have also been explored, but have not been commercially used. Development of DFM that are efficacious over a wide range of ruminant production systems remains challenging because[0] comprehensive knowledge of microbial ecology is lacking. Few studies have employed molecular techniques to study in detail the interaction of DFM with native microbial communities or the ruminant host. Advancements in the metagenomics of microbial communities and the genomics of microbial–host interactions may enable DFM to be formulated to improve production and promote health, responses that are presently often achieved through the use of antimicrobials in cattle.

Effects of probiotic inclusion levels in broiler nutrition on growth performance, nutrient digestibility, plasma immunoglobulins, and cecal microflora composition

The aim of this work was to investigate the effect of inclusion levels of a 5-bacterial species probiotic in broiler nutrition. Five hundred twenty-five 1-d-old male Cobb broilers were allocated in 5 experimental treatments for 6 wk. The experimental treatments received a corn-soybean coccidiostat-free basal diet and depending on the addition were labeled as follows: no addition (C), 10(8) cfu probiotic/kg of diet (P1), 10(9) cfu probiotic/kg of diet (P2), 10(10) cfu probiotic/kg of diet (P3), and 2.5 mg of avilamycin/kg of diet (A). Each treatment had 3 replicates of 35 broilers each. Treatment effects on broiler growth performance and biomarkers such as ileal and total tract nutrient digestibility, plasma Ig concentration, and cecal microflora composition were determined. Differences among treatments were considered significant when P < or = 0.05. Overall BW gain was significantly higher in treatment P1 (2,293 g) compared with P2 (2,163 g), C (2,165 g), and P3 (2,167 g), with A (2,230 g) being intermediate and not different from P1. Overall feed conversion ratio values were similar and significantly better for P1 (1.80) and A (1.80) compared with P2 (1.87), C (1.89), and P3 (1.92). Ileal apparent digestibility coefficients (ADC) of CP and ether extract were higher in A. Generally, treatments A and P1 showed an improved total tract ADC for DM, organic matter, ash, ether extract, and AME(n) values. The total tract ADC of CP was higher in P1, C, and P2. There were no differences between treatments regarding plasma Ig in 14- and 42-d-old broilers. Treatments P2 and P3 were effective at beneficially modulating cecal microflora composition. In particular, the lower cecal coliform concentration (log cfu/g of wet digesta) was seen in P2 (6.12) and P3 (4.90) in 14- and 42-d-old broilers, respectively, whereas at 42 d, P3 and P2 had the highest Bifidobacterium (8.31; 8.08) and Lactobacillus concentrations (8.20; 7.86), respectively. It is concluded that probiotic inclusion level had a significant effect on broiler growth responses, nutrient ADC, AME(n), and cecal microflora composition.

Effect of dietary antibiotic, probiotic and prebiotic as growth promoters, on growth performance, carcass characteristics and hematological indices of broiler chickens

This experiment was conducted for comparison the effects of antibiotic (flavomycin), probiotic (primalac), prebiotic (Biolex-MB) and mixture ofprobiotic and prebiotic (primalac plus Biolex-MB) as dietary growth promoter on growth performance, carcass characteristics and hematological indices of broiler chickens. Three hundred day old Ross 308 broilers were equally distributed into 30 floor pens and reared for 42 day. A basal diet was formulated covering the recommendations of NRC (1994) for starter (0-21 days) and grower (22-42 days) periods and considered as control diet. Four tested diets were formulated by supplemented the basal control diet with antibiotic (flavomycin), probiotic (primalac), prebiotic (Biolex-MB) and mixture ofprimalac plus Biolex-MB, respectively. Six replicates were used for each treatment. The results of present study showed that all growth promoters used was improved growth indices of Ross 308 broilers. The highest significant (p<0.05) values of carcass and thigh were recorded for broilers fed diet supplemented with flavomycin. The highest (p>0.05) value of breast was recorded for broilers fed the diet supplemented with primalac, meanwhile the lower value were showed for birds fed either diet or diet supplemented with Biolex-MB. The percent of carcass and cuts followed the same trend. Hematological parameter including cholesterol was recorded the highest (p>0.05) values groups fed the diets either control or supplemented with flavomycin, meanwhile the lower value was showed for bird fed diet supplemented primalac plus Biolex-MB. Triglycerides and very low density lipoprotein cholesterol (VLDL) were recorded the highest concentration for bird fed both control and diet supplemented with flavomycin groups while least concentration was found for bird fed diet supplemented with primalac. The results of present study revealed that probiotic and prebiotic as growth promoters can use as alternatives non-antibiotic feed additives to their free harmful side effects on the consumers and to improve broiler chickens growth indices.

Bacterial-mucosal interactions in inflammatory bowel disease: an alliance gone bad

The complex interaction of genetic, microbial, and environmental factors may result in continuous activation of the mucosal immune system leading to inflammatory bowel disease (IBD). Most present treatments for IBD involve altering or suppressing the aberrant immune response; however, the role of the intestinal microbiota in the pathophysiology of IBD is becoming more evident. The epithelial layer is essential for the proper functioning of the gastrointestinal tract, and its increased permeability to the luminal antigens may lead to the inflammatory processes and mucosal damage observed in IBD. Factors affecting the efficacy of the epithelial barrier include presence of pathogenic bacteria (e.g., Helicobacter spp.), presence of probiotic bacteria, availability of selected nutrients, and others. Defective function of the mucosal barrier might facilitate the contact of bacterial antigens and adjuvants with innate and adaptive immune cells to generate prolonged inflammatory responses. This review will briefly describe the complex structure of the epithelial barrier in the context of bacterial-mucosal interactions observed in human IBD and mouse models of colitis.

Interactions between commensal bacteria and the gut-associated immune system of the chicken

The chicken gut-associated lymphoid tissue is made up of a number of tissues and cells that are responsible for generating mucosal immune responses and maintaining intestinal homeostasis. The normal chicken microbiota also contributes to this via the ability to activate both innate defense mechanisms and adaptive immune responses. If left uncontrolled, immune activation in response to the normal microbiota would pose a risk of excessive inflammation and intestinal damage. Therefore, it is important that immune responses to the normal microbiota be under strict regulatory control. Through studies of mammals, it has been established that the mucosal immune system has specialized regulatory and anti-inflammatory mechanisms for eliminating or tolerating the normal microbiota. The mechanisms that exist in the chicken to control host responses to the normal microbiota, although assumed to be similar to that of mammals, have not yet been fully described. This review summarizes what is currently known about the host response to the intestinal microbiota, particularly in the chicken.

Performance Assessment of Broiler Chickens Given Mushroom Extract Alone or in Combination with Probiotics

A study was conducted to evaluate the effect of combined Shiitake mushroom (Lentinus edodes) extract with probiotics (PrimaLac) on the growth and health of broiler chickens. In trial 1, 540 d-of-hatch chicks were randomly assigned to 6 treatment groups, replicated 3 times, with 15 males and 15 females per pen for 3 wk. Dietary probiotics and mushroom treatments were as follows: 1) control feed + ad libitum tap water; 2) control feed + skip-a-day mushroom water; 3) control feed + ad libitum mushroom water; 4) probiotic feed + ad libitum tap water; 5) probiotic feed + skip-a-day mushroom water; 6) probiotic feed + ad libitum mushroom water. Body weight gain, feed consumption and efficiency, mortality, bursa, liver, and spleen relative weights of chicks were taken. In trial 2, the performance of broilers 3 to 7 wk withdrawn from the mushroom extract was evaluated along with the comparative level of fecal biofidobacteria in the control and mushroom extract treatment (trt). Mortality, weight gain, feed consumption and efficiency, carcass yield, fat pads, bursa weights and fecal bifidobacteria were measured in trial 2. In trial 1, significant differences (P < 0.05) in female weight gain (trt 4-0.62 vs. trt 1-0.54 kg) and male spleen weights were observed. In trial 2, significant differences were observed in male weight gain (trt 2-2.40 vs. trt 4-1.12 kg), male and female fat pads, male bursa weights (trt 3-0.15 vs. trt 6-0.39), female carcass yield percentage (trt 1-77.8 vs. trt 4-66.4), and feed consumption and efficiency. Body weights were severely depressed in the male broilers receiving the probiotics feed in treatments 4, 5, and 6, but not in the female broilers. These results indicate that performance differences in gender occur with additives during different grow-out periods, and mushroom extract promotes bifidobacteria growth in broiler chickens after 4 wk of withdrawal. It appears that probiotics and mushroom extract offered no combination potential for weight gain, which was compromised in this study, but possible health-enhanced attributes.

Microarchitecture and Spatial Relationship Between Bacteria and Ileal, Cecal, and Colonic Epithelium in Chicks Fed a Direct-Fed Microbial, PrimaLac, and Salinomycin

Direct-fed microbials (DFM) could serve as a potential alternative to the feeding of antibiotics in poultry production. In this study, the effects of providing a DFM were compared with the feeding of salinomycin on intestinal histomorphometrics, and microarchitecture was examined. Broiler chicks (n=18 per treatment; trials 1 and 2) were fed a standard starter diet (control), control+PrimaLac (DFM; 0.3% wt/wt), and control+salinomycin (SAL; 50 ppm) from hatch to 21d. The birds were euthanized on d 21, and the ileal, jejunal, cecal, and colon tissues were dissected. Samples were examined by light microscopy (jejunum and ileum; trial 1) and scanning electron microscopy (ileum, cecum, and colon; trial 2). Feeding of the DFM increased intestinal muscle thickness (P<0.05) up to 33% compared with the control treatment. The DFM group also had increased villus height and perimeter (P=0.009 and 0.003, respectively) in jejunum. Segmented filamentous-like bacteria were less numerous in DFM-treated chicks than in the control chicks. Very few segmented filamentous-like bacteria were found near other microbes in the ileum. The DFM chicks had a larger number of bacteria positioned over or near goblet cells and in intervilli spaces. Bacteria in the colon were observed to be attached primarily around and within the crypts. Mucous thickness was less, and the density of bacteria embedded in the mucous blanket appeared to be lower in DFM-treated animals than in the control in all intestinal segments. The birds fed SAL had fewer bacteria and enterocytes in the ileum than in the control-and DFM-treated birds, and they had thicker and fewer microvilli. Because gastrointestinal track colonization by the DFM organisms can prevent the attachment of pathogens to the epithelium, spatial relationships, in this study, demonstrate the functionality of DFM and probiotics in preventing disease. It also supports previous observations that the feeding of salinomycin may alter intestinal function.