Histological alterations of intestinal villi in chickens fed dried Bacillus subtilis var. natto

Probiotic alternatives to reduce gastrointestinal infections: the poultry experience

The intestinal mucosa represents the most active defense barrier against the continuous challenge of food antigens and pathogenic microorganisms present in the intestinal lumen. Protection against harmful agents is conferred by factors such as gastric acid, peristalsis, mucus, intestinal proteolysis, and the intestinal biota. The establishment of beneficial bacterial communities and metabolites from these complex ecosystems has varying consequences for host health. This hypothesis has led to the introduction of novel therapeutic interventions based on the consumption of beneficial bacterial cultures. Mechanisms by which probiotic bacteria affect the microecology of the gastrointestinal tract are not well understood, but at least three mechanisms of action have been proposed: production/presence of antibacterial substances (e.g., bacteriocins or colicins), modulation of immune responses and specific competition for adhesion receptors to intestinal epithelium. The rapid establishment of bacterial communities has been thought to be essential for the prevention of colonization by pathogenic bacteria. Some animal models suggest that the reduction in bacterial translocation in neonatal animals could be associated with an increase in intestinal bacterial communities and bacteriocin-like inhibitory substances produced by these species. This review emphasizes the role of the intestinal microbiota in the reduction of the gastrointestinal infections and draws heavily on studies in poultry.

Effects ofEnterococcus faeciumand dried whey on broiler performance, gut histomorphology and intestinal microbiota

The experiment was conducted to study the effects of supplementing a broiler starter diet with the probiotic Enterococcus faecium NCIMB 10415 and dried whey (80% lactose) on chick performance, gut histomorphology and intestinal microbiota. One-day-old male Ross 308 strain broiler chickens were fed diets containing: (i) control feed, (ii) control + 3.5% dried whey, (iii) control + 0.2% E. faecium, and (iv) control + 3.5% dried whey + 0.2% E. faecium. Birds were maintained in battery brooders confined in an environmentally controlled experimental room. The experiment lasted for 21 days. Birds fed E. faecium or E. faecium + dried whey exhibited significantly improved weight gain and feed conversion rate (FCR). Weight gain and FCR of treatment groups 1-4 were 628.7, 657.8, 690.9, 689.3 and 1.218, 1.193, 1.107, 1.116, respectively. Lactic acid bacteria counts in both the ileal content and excreta were significantly affected by dietary treatment. Supplementation of the E. faecium and dried whey separately and in combination increased lactic acid bacteria colonization in the ileal content from 4.2 to 5.0, 7.8 and to 5.1 log cfu/g, respectively (treatments 1-4). Similarly, supplementation of dried whey and E. faecium separately and in combination increased lactic acid bacteria in the excreta from 5.3 to 5.5, 8.0 and to 7.2 log cfu/g, respectively. Addition of the probiotic E. faecium increased villus height in the ileum (p < 0.05). Thus, supplementation of E. faecium enhanced broiler chick performance with respect to weight gain and FCR. No additive effect of E. faecium and dried whey was detected. Further studies are needed to investigate the relationship between E. faecium and dried whey with respect to gut histomorphology.

Histological alterations of the intestinal villi and epithelial cells in chickens fed dietary sugar cane extract

1. Sugar cane extract (SCE) is the residue after removing glucose, fructose and sucrose from sugar cane juice. To investigate the effects of dietary SCE on growth performance and alterations to intestinal histology, 36 male Sanuki Cochin chickens were divided into three groups: a control group was fed a commercial diet (180 g/kg CP, 13.59 MJ/kg ME) and the treatment groups were fed the commercial diet supplemented with 0.5 or 10 g/kg SCE ad libitum for 35 d. 2. Feed intake and weight gain tended to be higher in the 0.5 and 10 g/kg SCE groups than in the control group. No specific gross morphological alterations were observed in the visceral organs of chickens in any of the groups. However, intestinal villus height, villus area, epithelial cell area and cell mitosis in each intestinal segment had higher values in the SCE groups than in the control group. In the 0.5 and 10 g/kg SCE groups, but not in the control group, the cells on the villus apical surface protuberated and had larger cell clusters and some areas with cells with no microvilli. 3. The observed alterations to intestinal histology in chickens fed dietary SCE diets demonstrate that the function of villi and cells on the villus tip might be activated in all the intestinal segments and that cell turnover is also accelerated. These activated intestinal functions appear to promote growth and immuno-stimulation in chickens fed SCE diets, especially in the 0.5 g/kg group.

Histological Intestinal Recovery in Chickens Refed Dietary Sugar Cane Extract

Sugar cane extract (SCE), the residue after removing glucose, fructose, and sucrose from sugar cane juice, has growth-promoting, antistress, and immunostimulation effects. The objective of this study was to investigate the effects of refeeding dietary SCE on recovery of BW and intestinal histology after withdrawing feed from chickens. Forty-eight male Sanuki Cochin chickens were assigned randomly to 6 treatments and 8 replicates in a completely randomized design. The 6 treatments were intact control chickens fed ad libitum a basal commercial grower mash diet; 3 d of feed withdrawal; feed withdrawal followed by 1 d of ad libitum access to the same commercial mash diet (AFC); and free access to the commercial mash diet with 0.05, 1, or 3% SCE for 1 d. All SCE groups gained more weight in 1 d of refeeding than the AFC group (P < 0.05). Compared with the AFC group, the SCE groups increased cell mitosis (P < 0.05). On the villus apical surface, flat epithelial cells of the feed withdrawal group developed more protuberated cells than those of the intact control group in all refeeding groups. Compared with the AFC group, the SCE groups showed more protuberated cells. In addition, in the 0.05% SCE group, cell clusters aggregated by many cells were observed on the villus apical surface. The present histological intestinal alterations in chickens refed a SCE-containing diet demonstrate that the villi and epithelial cells might be hypertrophied because of some component in the SCE, resulting in quicker BW recovery in SCE-fed birds compared with those in the AFC group.

Broiler performance and intestinal alterations when fed drug-free diets

A study was carried out to investigate the effects of a drug-free feeding program on broiler performance and intestinal morphology. Chicks vaccinated against coccidia were randomly assigned to 4 dietary treatments: 1) negative control (NC), basal diet; 2) positive control (PC), diet 1 + Lincomycin; 3) program 1 (PG1); diet 1 + Bio-Mos, Vegpro, MTB-100, Acid Pak 4-Way, and All-Lac XCL; 4) and program 2 (PG2), diet 1 + Bio-Mos and All-Lac XCL, each of which were assigned to 13 pens (48 birds in each of 52 pens). Growth traits (BW, feed intake, yield, mortality, BW gain, and feed conversion rate) were obtained through 49 d. At d 14, 3 chicks per pen were challenged with coccidia. Segments of duodenum, ileum, and ceca were removed to measure intestinal morphology at d 14, 28, 35, and 49. Final BW gain of broilers on PC (2.736 kg) was numerically higher than those for NC (2.650 kg). Cumulative feed conversion rate at d 49 was improved (P < 0.05) in birds consuming PC and PG2 compared with NC. Overall, mortality was higher for birds consuming the NC (P < 0.05) than the PC, PG1, and PG2 diets. Interaction of dietary treatments with age and age alone were evident (P < 0.0001) for morphology of duodenum, ileum, and ceca. Lamina propria in ceca was thicker (P < 0.008) in broilers consuming the NC than PG1 and PG2 diets. The results of this study indicated that feeding birds without growth promoters resulted in higher mortality and decreased growth performance than did feeding a diet with an antibiotic, and the combination of Bio-Mos and All-Lac XCL helped to reduce negative effects.

The use of bacterial spore formers as probiotics: Table 1

The field of probiosis has emerged as a new science with applications in farming and aqaculture as alternatives to antibiotics as well as prophylactics in humans. Probiotics are being developed commercially for both human use, primarily as novel foods or dietary supplements, and in animal feeds for the prevention of gastrointestinal infections, with extensive use in the poultry and aquaculture industries. The impending ban of antibiotics in animal feed, the current concern over the spread of antibiotic resistance genes, the failure to identify new antibiotics and the inherent problems with developing new vaccines make a compelling case for developing alternative prophylactics. Among the large number of probiotic products in use today are bacterial spore formers, mostly of the genus Bacillus. Used primarily in their spore form, these products have been shown to prevent gastrointestinal disorders and the diversity of species used and their applications are astonishing. Understanding the nature of this probiotic effect is complicated, not only because of the complexities of understanding the microbial interactions that occur within the gastrointestinal tract (GIT), but also because Bacillus species are considered allochthonous microorganisms. This review summarizes the commercial applications of Bacillus probiotics. A case will be made that many Bacillus species should not be considered allochthonous microorganisms but, instead, ones that have a bimodal life cycle of growth and sporulation in the environment as well as within the GIT. Specific mechanisms for how Bacillus species can inhibit gastrointestinal infections will be covered, including immunomodulation and the synthesis of antimicrobials. Finally, the safety and licensing issues that affect the use of Bacillus species for commercial development will be summarized, together with evidence showing the growing need to evaluate the safety of individual Bacillus strains as well as species on a case by case by basis.