Flore fongique de différents substrats et conditions optimales de production des mycotoxines

Les moisissures sont des contaminants fréquents de nombreux substrats végétaux et de certains produits d'origine animale. Leur présence peut améliorer les qualités organoleptiques du produit ou, au contraire, l'altérer et conduire à l'accumulation de métabolites secondaires toxiques : les mycotoxines. L'objectif de ce travail a été de caractériser la flore fongique de différents substrats (céréales et produits de salaison) et d'étudier le potentiel toxinogène des souches isolées afin d'évaluer le risque mycotoxicologique associé à la consommation de ces aliments. Nous avons aussi caractérisé les conditions optimales de production de certaines mycotoxines. L'objectif était double : les comparer avec les conditions naturelles et déterminer les paramètres nécessaires à la production de grandes quantités de toxines partiellement purifiées. Ce dernier point est un préalable nécessaire à l'étude de l'impact de ces contaminants sur la santé animale et la qualité des produits d'origine animale. ABSTRACT : Moulds are common contaminants of a wide variety of vegetal and animal derived foods. Their presence can improve organoleptic properties or, contrary, lead to food spoilage and accumulation of toxic compounds: mycotoxins. The aim of this study was to characterize the fungal flora of several substrates (cereals and dry cured meat products) and to determine the toxigenic potential of isolated strains in order to appreciate the risk associated with consumption of such food products. We also characterized the optimal conditions for some mycotoxin production. The objectives were double: to compare them with natural conditions and to be able to produce large quantities of partially purified toxins. This later point is necessary to investigate effects of these contaminants on both animal health and quality of animal derived product

Preliminary Characterization of the Probiotic Properties of a Bacterial Strain for Used in Monogastric Nutrition

This study aimed to evaluate some probiotic properties of Bacillus subtilis ATCC 6051a. The phenotypic profile, resistance to pH by simulated gastric juice (pH 2 and 3), bile salts by simulated intestinal fluid, survivability (%), heat and antibiotics tolerance were investigated. The strain is a Gram-positive, rod-shaped bacteria, arranged in short chains or in small irregular pairs with the ability to produce spores. Good viability at pH 2 and 3, with a survival of more than ≥80%, was found. In the presence of bile salts 0.3%, over 4 h, the strain exhibited a survival ≥85%. At 80°C, for 120 min., the strain showed good growth (9.04 log CFU/ml). Results were sensitive to most antibiotics, with a highly susceptible (between 16 – 25 mm) to erythromycin, clindamycin, amoxicillin, chloramphenicol, ciprofloxacin, amikacin and kanamycin. The strain was found to be sensitive to vancomycin, gentamicin, and tetracycline. The present research demonstrated that Bacillus subtilis ATCC 6051a can survive under gastrointestinal conditions, which involves them to future in vitro and in vivo probiotic studies

Preliminary Characterization of the Probiotic Properties of a Bacterial Strain for Used in Monogastric Nutrition

This study aimed to evaluate some probiotic properties of Bacillus subtilis ATCC 6051a. The phenotypic profile, resistance to pH by simulated gastric juice (pH 2 and 3), bile salts by simulated intestinal fluid, survivability (%), heat and antibiotics tolerance were investigated. The strain is a Gram-positive, rod-shaped bacteria, arranged in short chains or in small irregular pairs with the ability to produce spores. Good viability at pH 2 and 3, with a survival of more than ≥80%, was found. In the presence of bile salts 0.3%, over 4 h, the strain exhibited a survival ≥85%. At 80°C, for 120 min., the strain showed good growth (9.04 log CFU/ml). Results were sensitive to most antibiotics, with a highly susceptible (between 16 – 25 mm) to erythromycin, clindamycin, amoxicillin, chloramphenicol, ciprofloxacin, amikacin and kanamycin. The strain was found to be sensitive to vancomycin, gentamicin, and tetracycline. The present research demonstrated that Bacillus subtilis ATCC 6051a can survive under gastrointestinal conditions, which involves them to future in vitro and in vivo probiotic studies

Maintaining intestinal microflora balance in heat-stressed broilers using dietary creeping wood sorrel (Oxalis corniculata) powder and chromium (chromium picolinate)

This study aimed to determine the effect of dietary creeping wood sorrel powder (Oxalis corniculata) and chromium supplemented to broilers (1-42 days) exposed to heat stress, on their performance and on the intestinal and caecal microbiota.Area of study: Ilfov, RomaniaMaterial and methods: The feeding trial was conducted on 60, day-old Cobb 500 broilers, divided equally in two groups, each group with six replicates (5 chicks/ replicate). The broilers were housed in an experimental hall at 32° C constant temperature and 23h light regimen. Unlike the dietary control diet (C), the experimental diet (E) was supplemented with 1% creeping wood sorrel powder and 20 mg chromium picolinate/ kg premix. One bird from each replication was slaughtered on days 28 and 42, and samples of caecal and intestinal content were collected for bacteriological analysis.Main results: The dietary creeping wood sorrel powder and chromium supplements for heat-stressed broilers had no significant influence on their growth performance (1-42 d). Overall, E diet had a beneficial effect on the balance of the caecal microflora; however, in the intestine, E diet had a positive influence on the balance of the intestinal microflora, only for the samples collected at 28 days.Research highlights: Dietary creeping wood sorrel powder and chromium supplements can be an efficient tool for maintaining a proper balance of intestinal microflora in heat-stressed broilers.

Dietary Willow Bark Extract for Broilers Reared Under Heat Stress

A 28-day feeding trial was conducted on 60, Cobb 500 broilers (14 days), assigned to 2 groups (C, E) housed in an experimental hall (32° C, 23 h light regimen). Compared to the conventional diet C, the experimental diet (E) included 1% white willow bark extract (WBE). At 42 days of age, 6 blood samples /group were collected and 6 broilers/ group were slaughtered and caecal content was collected. The dietary WBE didn’t influence broiler performance. The serum concentrations of glycaemia, cholesterol and triglycerides were lower (P <0.05) in E group than in C group. E broilers had the lowest count (P<0.05) of Enterobacteriaceae, E. coli and staphylococci colony forming units in the caecal content. The inclusion of WBE (1%) in the diet of broilers reared at 32° C had an hypocholesterolemiant and hypoglycaemic effect and reduced the pathogenic bacteria in the caecum

Dietary ascorbic acid and chromium supplementation for broilers reared under thermoneutral conditions vs. high heat stress

The present study evaluates the effect of dietary ascorbic acid and chromium (AACr) on performance and microflora balance of broiler reared under thermoneutral conditions (TN) vs. high heat stress (HS). Two experiments were conducted on 112 Cobb 500 broilers, assigned in two experimental groups (28 chickens/group) and housed in an environmental controlled hall. Two groups (C-TN and AACr-TN) were kept in thermoneutral conditions. In the second experiment, other two groups were kept (C-HS and AACr-HS) in high heat stress (32° C). The structure of diets was the same in both experiments. Compared with the control diet (C), the experimental diet included the addition of a premix with 25 g ascorbic acid / kg premix + 20 mg chromium picolinate/ kg premix (AACr). At the end of the experiment, 8 broilers / group were slaughtered and samples of intestinal and caecal content were collected for bacteriological assessment. Dietary AACr did not affect (p>0.05) body weight, daily feed intake, feed conversion rate neither under TN nor under HS condition. The use of AACr in broiler diet led to a significantly reduction of staphylococci in the caecum. Both in caecum and intestinal content of AACr broilers, irrespective the temperature conditions the number of lactobacilli was significantly higher than in the C broilers. Combination of ascorbic acid and Cr (AACr) has a positive effect in limiting the development of the pathogenic bacteria colonizing the intestine and caecum during the heat stress

Piglets’ Intestinal Microflora Fed with a Plants Mix

The objective of this study was to evaluate the effect of a plant mix (bilberry, black currant, quince, peppermint and fennel essential oil) inclusion into the diets of piglets (18-45 kg) on intestinal microflora equilibrium. An experiment was performed on 8 castrated hybrid TOPIGS (18.69±1.25 kg) divided in 2 groups (C and E). The piglets were kept in an experimental house in individual metabolic cages. Compared to the conventional diet (18% crude protein and 3214 kcal/kg metabolic energy) of group C, the diet of E group had included 789 mg mixture of plants/kg feed. At the final of the experiment the piglets were slaughtered and digesta samples were collected from jejunum and ileum for microbiological analysis. For jejunum, a significant (P<0.05) decrease of Staphylococci spp. (log10 CFU/g) concentration in E group was noticed correlated strongly negative with a statistically significant (P<0.05) increasing concentration of Lactobacillus spp. (log10 CFU/g) concentration. The results were similar for ileum. This dietary mixture of plants had some effects on microbial population of piglets’ jejunum and ileum to help positively the intestinal changes of microbiota

Blood Parameters, Digestive Organ Size and Intestinal Microflora of Broiler Chicks Fed Sorghum as Partial Substitute of Corn

A study was conducted to evaluate the effects of dietary white sorghum (WS), as partial substitute of corn on blood parameters, digestive organ size and intestinal microflora of broilers at 35 d. Cobb 500 broilers (n=400), assigned to 2 groups, were fed with isocaloric and isonitrogenous corn-soybean meal control diets (C) or corn-WS-soybean meal diets (WS), where corn was partially replaced (50%) with WS. At 35 d, sixteen broilers per group were selected for blood sampling, gastrointestinal (GIT) measurements, digesta pH and ileum microflora analysis. There was no effect (P>0.05) of the dietary WS inclusion on blood biochemistry parameters, GIT development and digesta pH of broilers. In our study, dietary WS significantly reduced the ileal population of Enterobacteriaceae (-1.38%; P<0.0001) and E. coli (-1.16%; P=0.020), and increased the Lactobacillus spp. (+1.07%; P=0.014) compared with the C diet. In conclusion, feeding white sorghum, as partial substitute of corn in broiler diets, did not affect blood parameters, digestive organ size and digesta pH, that support the obtained performance. In addition, sorghum had a positive effect of the ileal microflora increasing the beneficial bacterial Lactobacillus spp

Maintaining intestinal microflora balance in heat-stressed broilers using dietary creeping wood sorrel (Oxalis corniculata) powder and chromium (chromium picolinate)

This study aimed to determine the effect of dietary creeping wood sorrel powder (Oxalis corniculata) and chromium supplemented to broilers (1-42 days) exposed to heat stress, on their performance and on the intestinal and caecal microbiota.Area of study: Ilfov, RomaniaMaterial and methods: The feeding trial was conducted on 60, day-old Cobb 500 broilers, divided equally in two groups, each group with six replicates (5 chicks/ replicate). The broilers were housed in an experimental hall at 32° C constant temperature and 23h light regimen. Unlike the dietary control diet (C), the experimental diet (E) was supplemented with 1% creeping wood sorrel powder and 20 mg chromium picolinate/ kg premix. One bird from each replication was slaughtered on days 28 and 42, and samples of caecal and intestinal content were collected for bacteriological analysis.Main results: The dietary creeping wood sorrel powder and chromium supplements for heat-stressed broilers had no significant influence on their growth performance (1-42 d). Overall, E diet had a beneficial effect on the balance of the caecal microflora; however, in the intestine, E diet had a positive influence on the balance of the intestinal microflora, only for the samples collected at 28 days.Research highlights: Dietary creeping wood sorrel powder and chromium supplements can be an efficient tool for maintaining a proper balance of intestinal microflora in heat-stressed broilers.

Current Situation of Mycotoxin Contamination and Co-occurrence in Animal Feed—Focus on Europe

Mycotoxins are secondary metabolites produced by fungi especially those belonging to the genus Aspergillus, Penicillum and Fusarium. Mycotoxin contamination can occur in all agricultural commodities in the field and/or during storage, if conditions are favourable to fungal growth. Regarding animal feed, five mycotoxins (aflatoxins, deoxynivalenol, zearalenone, fumonisins and ochratoxin A) are covered by EU legislation (regulation or recommendation). Transgressions of these limits are rarely observed in official monitoring programs. However, low level contamination by Fusarium toxins is very common (e.g., deoxynivalenol (DON) is typically found in more than 50% of the samples) and co-contamination is frequently observed. Multi-mycotoxin studies reported 75%–100% of the samples to contain more than one mycotoxin which could impact animal health at already low doses. Co-occurrence of mycotoxins is likely to arise for at least three different reasons (i) most fungi are able to simultaneously produce a number of mycotoxins, (ii) commodities can be contaminated by several fungi, and (iii) completed feed is made from various commodities. In the present paper, we reviewed the data published since 2004 concerning the contamination of animal feed with single or combinations of mycotoxins  and highlighted the occurrence of these co-contaminations