The choline content of feed ingredients and mixed feeds determined by an enzymatic assay

A recently developed procedure for the determination of choline in ingredients and feeds was utilised to establish the levels and the variability of choline in a series of ingredients and to compare the analysed and calculated choline values of mixed feeds. The concentrations of choline in samples of maize (7), canola meal (3), wheat middlings (1) and dehydrated bakery product (1) were, respectively, 1·55±0·18, 7·59±0·08, 2·35 and 2·39 g kg⁻¹, all higher than ingredient composition table values. Choline contents lower than table values were found in samples of poultry by-products (7) and meat and bone meal (6): 2·18±0·87 and 1·08±0·29 g kg⁻¹, respectively. The average choline concentration found in samples of dehulled soybean meal (7) was 2·73±0·18 g kg⁻¹, similar to table values. The choline in samples of poultry fat (2) averaged 0·48±0·02 g kg⁻¹. Significant correlations between the concentrations of choline and of some components of the proximate analysis were found. The analysed choline concentrations in mixed feeds were only 1·4% lower than the calculated levels based on the ingredient analyses. The procedure was adequate for choline determination in ingredients or mixed feeds. The high variability in the choline content of some ingredients may require analysis for proper feed formulation. © 1998 Society of Chemical Industry.     

Comparative study on decontamination of mixed feeds by radicidation and by pelletisation

Feed components contaminated with Salmonella act as vehicles in the transmission of these bacteria to animals and hence to meat and poultry. Sanitary improvements in processing, bagging and storage do not always effectively reduce Salmonella contamination rates and therefore ingredients or mixed feed should be decontaminated at the end of processing. Enumeration of Enterobacteriaceae was used to assay the decontamination effect of pelletisation of mixed feed. A working temperature over 80° usually reduced the bacterial count by a factor of 10⁵; lower temperatures currently used, reduced it by a factor of 10³ only. In similar dose-range-finding tests on decontamination with ⁶⁰Co gamma rays, about 0.5 Mrad were required for reductions in the counts of the most resistant Enterobacteriaceae by a factor of 10⁵. Survival curves being usually non-linear, ‘gross effective dose’ had to be used as a parameter. Neither loss of nutritive value nor the occurrence of orally toxic factors was observed when rats were fed for 2 years on a ration containing 35% fishmeal irradiated at 0.8 Mrad. A combination of improved sanitation, pelletising at the highest possible temperature and, if still required, terminal low-dose irradiation of the hermetically bagged material seems, therefore, a promising approach to the manufacture of Salmonella-free feeds.     

Natural occurrence of zearalenone and trichothecene toxins in maize-based animal feeds in zambia

A year-long collection of maize-based animal feed samples from the National Milling Company and mouldy maize collected from farmers fields near Lusaka were analysed for Fusarium mycotoxins. In the survey, 148 samples were tested for zearalenone, deoxynivalenol and nivalenol, and 60 samples for T-2 toxin and diacetoxyscirpenol. Zearalenone was present up to 0.6 mg kg^?1 in 17% of the feed samples, and deoxynivalenol was found at I-0 mg kg^?1 in 1.4 % of these samples. This is the first report of these toxins in animal feeds in Zambia. Zearalenone was also found in 57.6 % of the 33 mouldy maize samples collected at levels ranging from 0.08 to 6.0 mg kg^?1 (mean concentration 1.11 mg kg^?1), and 49.5% of these samples contained deoxynivalenol at levels ranging from 0.5 to 16.0 mg kg^?1 (mean concentration 5.56 mg kg ^?1). T-2 toxin and diacetoxyscirpenol were not detected.     

Detection of ochratoxin A in animal feeds and capacity to produce this mycotoxin by Aspergillus section Nigri in Argentina.

Ochratoxin A (OA) is a mycotoxin detected in a variety of food and feeds mostly from countries with a temperate climate because of the fungi that produce it, mainly Aspergillus ochraceus and Penicillium verrucosum. In Argentina, there is no available information about the natural occurrence of OA and ochratoxigenic fungi from feedstuffs. The aim was to evaluate the natural occurrence of OA in poultry, pig and rabbit feeds over 8 months. Likewise, the capacity to produce OA by Aspergillus section Nigri was investigated. Mycotoxin analysis showed that in some months of sampling, OA was detected in three feeds. OA was found in 38% of the poultry feed samples tested with levels ranging from 25 to 30 ng g(-1). From rabbit feed samples, 25% contained OA and the levels ranged from 18.5 to 25 ng g(-1). Only 13% of the pig feed samples were contaminated with similar levels of toxins. Ninety-four black Aspergillus strains from feedstuffs were tested for OA production. Among these, the tested species were A. niger var. niger, A. niger var. awamori, A. japonicus var. japonicus, A. japonicus var. aculeatus and A. foetidus. For the detection of OA, three methodologies were applied: the two TLC methods used for the fast screening of the filamentous fungi for the production of OA were not sensitive enough to detect OA in any of the black Aspergillus strains. When an HPLC methodology was used, the results showed that 46% of the black Aspergillus strains were producers of OA, with levels ranging from 13 to 25 ng ml(-1) culture medium. The highest percentage of ochratoxicogenic strains was isolated from rabbit feeds with 100 and 78% of A. niger var. niger and A. niger var. awamori, with mean levels of 15.5 and 14.6 ng ml(-1), respectively. From pig feeds, 61% of the A. niger var. awamori were producers of this toxin with mean levels of 16 ng ml(-1). In poultry feeds, the lowest percentage of OA producer strains was detected. The results for the occurrence of OA in feeds from different sampling months depended on storage and humidity-temperature conditions. Therefore, a good storage practice becomes very important to prevent OA production     

STUDIES ON THE MYCOFLORA OF MALT

The mycoflora of malt which caused gushing beer has been investigated and compared with the mycoflora of malt from nine malting plants in Sweden, Denmark, Finland and England. Malt which caused gushing beer was found to contain a high proportion of grains contaminated by Aspergillus, Penicillium and Rhizopus. The commonest species isolated were found to be Aspergillus fumigatus and Aspergillus amstelodami. These fungi occurred on all malt samples investigated independent of their origin. The mycoflora on malt differs greatly from that found on barley. Evidence is presented showing that barley becomes contaminated during the malting process.     

Determination of nitrofurans residues in animal feeds by flow injection chemiluminescence procedure

A simple flow injection chemiluminescence (FI-CL) method was developed for the rapid and sensitive determination of nitrofurans, including furazolidone, nitrofurantoin and nitrofurazone, in animal feeds based on its chemiluminescence induced by potassium permanganate in sulphuric acid medium. The method involves the injection of nitrofuran samples or standards into H₂SO₄ carrier stream, which then merges at a T-piece with a reagent stream consisting of KMnO₄ in the H₂SO₄ carrier solution. The elicited chemiluminescence intensity of the resulting reaction mixture was measured by photomultiplier tube operated at a voltage of 950 V. Optimum CL signals were given using 2.5 × 10⁻⁵ mol L⁻¹ potassium permanganate in 0.1 mol L⁻¹ sulphuric acid as an oxidant stream and a carrier stream of 0.1 mol L⁻¹ sulphuric acid with a total flow rate of 7.0 mL min⁻¹. Results detailing the optimisation of the analytical signal, calibration, and common interferences of animal feeds were also discussed. The proposed FI-CL method was successfully applied to the determination of nitrofurans in animal feeds, with excellent recoveries, as the determination is free from interference. The method validation has been compared versus HPLC method for animal feed samples.     

Detection of rabbit and hare processed material in compound feeds by TaqMan real-time PCR

Food and feed traceability has become a priority for governments due to consumer demand for comprehensive and integrated safety policies. In the present work, a TaqMan real-time PCR assay targeting the mitochondrial 12S rRNA gene was developed for specific detection of rabbit and hare material in animal feeds and pet foods. The technique is based on the use of three species-specific primer/probe detection systems targeting three 12S rRNA gene fragments: one from rabbit species, another one from hare species and a third fragment common to rabbit and hare (62, 102 and 75 bp length, respectively). A nuclear 18S rRNA PCR system, detecting a 77-bp amplicon, was used as positive amplification control. Assay performance and sensitivity were assessed through the analysis of a batch of laboratory-scale feeds treated at 133°C at 3 bar for 20 min to reproduce feed processing conditions dictated by European regulations. Successful detection of highly degraded rabbit and hare material was achieved at the lowest target concentration assayed (0.1%). Furthermore, the method was applied to 96 processed commercial pet food products to determine whether correct labelling had been used at the market level. The reported real-time PCR technique detected the presence of rabbit tissues in 80 of the 96 samples analysed (83.3%), indicating a possible labelling fraud in some pet foods. The real-time PCR method reported may be a useful tool for traceability purposes within the framework of feed control.     

Spoilage moulds and aflatoxins from poultry feeds

Aflatoxin producing strains of Aspergillus flayus Link (IMI 280819) and A. oryzae (Ahlb.) Cohn (IMI 280831) were among the eleven spoilage moulds isolated from five types of poultry feeds. The recorded pH and moisture content values of the various feeds are conducive to mould deterioration. All the four principal aflatoxins (B₁, B₂, G₁, G₂) were detected in the analysed feeds though at toxicologically ‘safe’ levels for most farm animals. Significant quantities of aflatoxin B₁ were produced by the two fungal isolates in all the five classes of poultry feeds with A. flavus yielding the larger amounts. Optimum aflatoxin B₁ production and mycelial growth in chick mash infusion medium were recorded for both species at 30 and 35 °C, respectively and similarly on the 8th and 6th day respectively when cultures were incubated at 30 °C.     

Occurrence of aflatoxins and ochratoxin A in Indian poultry feeds

From 1998 to 2001, 216 ingredients intended for incorporation into chicken feed, which included groundnut cake, maize, millets, rice bran, sorghum, soybean, sunflower, and mixed feeds, were assayed for aflatoxins and ochratoxin A contamination using an indirect competitive enzyme-linked immunosorbent assay. Thirty-eight percent of the samples were contaminated with aflatoxins and 6% with ochratoxin A. The incidence scores of aflatoxin contamination in excess of 10 microg/kg were 41 of 95 for maize, 18 of 30 for mixed feeds, 10 of 37 for groundnut, 6 of 29 for sorghum, 5 of 10 for sunflower, 3 of 14 for rice bran, and 1 of 8 for millet. Ochratoxin A contamination, in excess of 10 microg/kg, was found in 9 of 29 sorghum samples, 1 of 27 groundnut samples, 1 of 14 rice bran samples, 1 of 10 sunflower samples, and 2 of 8 millet samples. Ochratoxin A was not found in maize and mixed feeds. None of the three soybean samples contained ochratoxin A. This is the first report, to our knowledge, of co-occurrence of aflatoxins and ochratoxin A in Indian poultry feeds. The results confirm the importance of analysis of ingredients before incorporating them into mixed feeds.     

Detection of Listeria spp. in faeces from animals,in feeds,and in raw foods of animal origin

Thirty-nine samples of feeds and 79 faecal samples were collected at seven different dairy farms, at some of which the cows were suffering from Listeria mastitis. Faecal samples were also collected from poultry on a dairy farm and from cages used for transportation of poultry to slaughter. Also neck-skin samples were taken from 17 carcasses of dressed poultry, and five samples of scalding and chilling water at a poultry slaughterhouse. Finally, 67 samples of minced beef were collected from retail shops. The overall results show that approximately 82% of the feed samples harboured Listeria spp. and 62% Listeria monocytogenes. The faecal samples showed that 67% harboured Listeria spp. and 51% L. monocytogenes. In the minced beef samples, Listeria spp. could be demonstrated in 67% and L. monocytogenes in 28%. Of the faecal samples from poultry, 33% harboured Listeria spp. and also 33% L. monocytogenes. Listeria spp. were detected in 94% of the poultry neck-skin samples, and L. monocytogenes in 47%. Almost all L. monocytogenes from faeces and feeds agglutinated Listeria antisera against serotypes 1–4, while only 71% of the strains from minced beef agglutinated the same antisera. The high prevalence of positive findings indicates that the isolation method used is suitable for detection Listeria spp. in heavily contaminated material as well as in foods with low bacterial counts.     

Evaluation of detergent extraction procedures for characterising carbohydrate components in ruminant feeds and digesta

Steers fitted with simple rumen and abomasal cannulas were given isoenergetic diets of approximately equal amounts of untreated (UT) barley straw and concentrates (flaked maize + tapioca) alone (BS) or with urea (BSU) or fishmeal (BSF). Similar diets were also given in which the barley straw had been treated (AT) with NaOH (BSA, BSAU and BSAF respectively). The diets were given in a 6 × 6 Latin square design. Feed components and abomasal digesta samples were analysed for neutral (NDF) and acid (ADF) detergent fibres and for monosaccharide constituents of structural polysaccharides. Hemicellulose contents were estimated as the sum of xylose + arabinose (X + A) and by the difference between ash-free NDF and ash-free ADF (NDF-ADF). Cellulose was estimated as β-linked glucose (C) and by the difference between ash-free ADF and lignin (ADF–L).¹⁰³ Ruthenium and PEG were given as flow markers and flows (g24h^?1) at the abomasum of carbohydrate components estimated in these ways were calculated. Approximately 98% (by wt.) of the cellulose (C) found in original feed and digesta samples was recovered in both NDF and ADF. Recoveries of hemicellulose (X + A) in NDF from UT straw, AT straw and abomasal digesta were approximately 92, 48 and 50%, respectively. The ADF fraction of feeds and digesta contained 3–6 and 10–17% of the nitrogen and xylose, respectively, present in the original samples. Mouth to abomasum digestibilities of hemicellulose (NDF– ADF) for diets BS, BSU, BSF, BSA, BSAU and BSAF were 39, 62, 67, 29, 61 and 76%, respectively. Corresponding values for cellulose (ADF–L) were 37, 34, 50, 45, 48, and 63%, respectively. The use of NDF–ADF and ADF–L as measures of hemicellulose and cellulose contents, respectively, of feeds and digesta, and the digestibility of these carbohydrate fractions between mouth and abomasum of steers are discussed.     

Rapid determination of gizzerosine in fish meals using microchip capillary electrophoresis with laser-induced fluorescence detection

ABSTRACT

Sensitive detection of gizzerosine, a causative agent for deadly gizzard erosion in chicken feeds, is very important to the poultry industry. In this work, a new method was developed based on microchip capillary electrophoresis (MCE) with laser-induced fluorescence (LIF) detection for rapid analysis of gizzerosine, a biogenic amine in fish meals. The MCE separation was performed on a glass microchip using sodium dodecyl sulfate (SDS) as dynamic coating modifier. Separation conditions, including running buffer pH and concentration, SDS concentration, and the separation voltage were investigated to achieve fast and sensitive quantification of gizzerosine. The assay proposed was very quick and could be completed within 65 s. A linear calibration curve was obtained in the range from 0.04 to 1.8 μg ml^–1 gizzerosine. The detection limit was 0.025 μg ml^–1 (0.025 mg kg^–1), which was far more sensitive than those previously reported. Gizzerosine was well separated from other endogenous components in fish meal samples. Recovery of gizzerosine from this sample matrix (n = 3) was determined to be 97.2–102.8%. The results from analysing fish meal samples indicated that the present MCE-LIF method might hold the potential for rapid detection of gizzerosine in poultry feeds.     

Mycoflora and deoxynivalenol in whole wheat grains (Triticum aestivum L.) from Southern Brazil

The fungal species Fusarium graminearum is related to deoxynivalenol (DON) formation. The aim of this study was to evaluate mycoflora and DON occurrence in 53 whole wheat grain samples collected in Southern Brazil during the 2012 crop. Wheat grains showed adequate values of water activity ranging from 0.48 to 0.72, within the required limits of moisture content, ranging from 9.1% to 13.9%. In addition, low counts of fungal colonies, ranging from 10 to 8.2 × 10², were found. For Fusarium genera, there was predominance of Fusarium verticillioides (34%) and F graminearum (30.2%). For Aspergillus species, 37.7% of Aspergillus flavus was determined. Regarding the Penicillium species, Penicillium digitatum (49%) was the most found species. DON was detected in 47.2% (25 out of 53) of the samples analysed, with levels ranging from 243.7 to 2281.3 µg kg^?1 (mean: 641.9 µg kg^?1).     

Occurrence of mycotoxigenic fungi and mycotoxins in animal feed from bihar,india

A total of 387 samples comprising animal feed, poultry feed and cattle cakes from India were examined in order to isolate mycotoxin-producing fungi as well as mycotoxins. Of 385 Aspergillus flavus group isolates 53% were capable of producing aflatoxins in liquid SMKY medium. Toxigenic strains of other mycotoxigenic fungi, viz A ochraceus, A versicolor, Penicillium citrinum and Fusarium moniliforme, were also recorded. In feed samples, beside the aflatoxins present in 139 samples zearalenone, ochratoxin A and citrinin were also recorded alone or as cocontaminants. A monsoon climate together with the socioeconomic conditions of this region are important determinants for the high incidence of mycotoxins in animal food.     

The production of aflatoxins in fresh date fruits and under simulated storage conditions

Sixteen varieties of date fruit (Phoenix dactylifera) at three stages of maturation (Kimri, Rutab and Tamr) were examined for the presence of fungi and analysed for aflatoxins B₁, B₂, G₁ and G₂ and sterigmatocystin. Single samples of each variety were used in the study. Samples as received were initially examined for mycoflora and toxin levels and then stored at 98% relative humidity and 30 °C for 14 days to investigate the effects of possible adverse storage conditions on mycoflora and, in particular, aflatoxin formation. All samples showed an absence of aflatoxins and their precusor, sterigmatocystin, after adverse storage for 14 days, although aflatoxin‐producing Aspergillus flavus isolates were identified in 10 varieties at the first stage of maturation (Kimri). High fungal counts were associated with the Rutab stage and low counts with the Tamr stage. The counts of A flavus ranged from 5.00 to 8.16 log₁₀(cfu g^?1) under simulated storage conditions, and three varieties contained significant levels of aflatoxin B₁ or B₂ ranging from 35 to 11 610 µg kg^?1. Sterigmatocystin was not detected in any of the samples as received or under simulated storage conditions. © 2002 Society of Chemical Industry     

A rapid h.p.l.c. method for the determination of methionine hydroxy analogue free acid in supplemented feeds

Two methods are described for determining methionine hydroxy analogue free acid (HMB) in supplemented poultry feeds. The procedure is based on extraction of analogue from the feed, followed by high-pressure liquid chromatographic measurement of the HMB directly after extraction or, more rigorously, after extraction and hydrolysis of oligomers to monomer. Recoveries of HMB over the supplementation range 0.08–0.25% (by wt) are 98% with coefficients of variation of 5.4% in commercial poultry feeds. A 98% correlation coefficient is obtained when the analyses are compared with the gas chromatographic method.     

Polymerase chain reaction detection of bacterial ribosomal genes from fresh and stored animal feeds

Feed quality can be influenced by both the microbial population levels and types of organisms that become associated with the feed matrices during processing and storage. Evaluation of microbial quality of animal feeds is difficult, because feeds generally contain a diverse bacterial population that can fluctuate widely depending on a variety of factors. Microbial diversity may be investigated in animal feed using the polymerase chain reaction (PCR) and 16S rDNA primers. In this study a bacterial isolation step involving centrifugation was combined with several DNA extraction techniques, and PCR amplicons were visualised on electrophoresis gels. Seven different animal feeds and two commonly used feed ingredients, either fresh or stored for approximately 14 months at ?20 °C, were chosen (18 feed sources in total) to represent a variety of different matrices, concentrations of macronutrients such as protein and fat, and particle sizes. DNA extraction involving polyethylene glycol 8000 appeared to be the most reliable protocol for the extraction of community DNA for PCR analysis of feeds. The majority of the feeds (14 out of 18 animal feeds and feed ingredients) examined in this study yielded at least one PCR‐positive replicate (1.1 kb band on gel), whereas no amplified products could be obtained from either of the other two DNA extraction protocols. Although some protocol refinement may be necessary for individual feeds, this approach has the potential to be a reliable method for monitoring microbial diversity changes in feeds and for rapid, simultaneous detection of a wide variety of micro‐organisms in animal feeds during processing and storage. © 2002 Society of Chemical Industry     

Animal Feed Production and Contamination by Foodborne Salmonella

Animal feeds can potentially become contaminated with foodborne Salmonella either during harvesting, processing at the feed mill or during storage. Any environment that comes in contact with feed during these stages that also harbors Salmonella can theoretically contaminate the feed. This also holds true for ingredients that are combined with feeds as they are being mixed at the feed mill. Animal feeds are also potential reservoirs for cross contamination from Salmonella containing vectors and environmental sources while being fed to animals. Although several factors may determine the extent of contamination, the potential for infection in animals these have not been well characterized. In addition, certain animal management and feeding programs can lead to animals becoming more susceptible to Salmonella colonization and invasion. Control measures to limit Salmonella contamination of feed include agents that directly reduce or destroy the organism in feed. Antimicrobial compounds and management strategies have also been developed for preventing colonization and eliminating Salmonella colonized in the gastrointestinal tract. The future prospects for minimizing Salmonella contaminated feed will probably involve combining more efficient monitoring and sampling approaches with more rapid and sensitive detection technologies.

---

Zusammenfassung (Redaktion). Futtermittel k?nnen schon bei der Ernte der Futterpflanzen sowie w?hrend der Futter-Herstellung oder -Lagerung von Salmonellen kontaminiert werden; grunds?tzlich kann dies überall dort passieren, wo Futtermittel mit der Au?enwelt (mit Salmonellen) in Kontakt kommen. Dies gilt ebenso für Zusatzstoffe, die den Futtermitteln in Futtermühlen beigemengt werden. Futtermittel sind auch potenzielle Reservoire für die Kontamination mit Salmonellen w?hrend des Fütterns von Tieren. Obwohl das Ausma? einer solchen Kontamination mit Salmonellen von etlichen Faktoren bestimmt wird, sind die Umst?nde, die zur Infektion der Tiere führen k?nnen, noch nicht ausreichend charakterisiert worden. Au?erdem k?nnen bestimmte Tierhaltungs- und Fütterungsverfahren eine Infektion von Tieren durch Salmonella sogar begünstigen. Um dieses zu verhindern, k?nnen Wirkstoffe eingesetzt werden, welche die Salmonella-Populationen im Futter reduzieren oder zerst?ren. Es wurden ebenso Verfahren mit antimikrobiell wirksamen Stoffen entwickelt, um eine Besiedlung des Gastrointestinaltraktes durch Salmonella zu verhindern bzw. dort bereits vorhandene Samonellen abzut?ten. Zukünftig mu? ein effektiveres Monitoring- und Probenahme-Verfahren mit schnelleren und empfi ndlicheren Nachweisverfahren kombiniert werden, um eine eventuelle Kontamination von Futtermitteln durch Salmonella zu minimieren.

     

A survey of ochratoxin A contamination in feeds and sera from organic and standard swine farms in northwest Italy

BACKGROUND: A survey was carried out on conventional (n = 11) and organic (n = 4) swine farms in northwest Italy in order to investigate the occurrence of ochratoxin A (OTA) in feed and serum samples collected from September 2006 to March 2009. Each farm was sampled twice and a total of 30 feed samples and 285 serum samples were collected. OTA levels were determined through extraction, immunoaffinity column purification and high‐performance liquid chromatography analysis coupled with fluorimetric detection. RESULTS: All feed samples resulted to be contaminated with OTA at levels ranging from 0.22 to 38.4 µg kg^?1. The OTA concentrations found in organic feed samples were significantly higher (P < 0.05) than those found in conventional feed samples. All serum samples resulted to be contaminated with OTA at levels ranging from 0.03 to 6.24 ng mL^?1. The OTA concentrations found in organic serum samples were significantly higher (P < 0.001) than those found in conventional serum samples. CONCLUSION: None of the feed samples contained more than the maximum level (50 µg OTA kg^?1, considering a feed moisture content of 120 g kg^?1) recommended by the European Commission for OTA in complementary and complete swine feedstuffs. The OTA contamination of organic feed and serum samples was found to be significantly higher than that of conventional feed and serum samples. Copyright © 2010 Society of Chemical Industry     

Rapid detection of aflatoxin-producing strains of the Aspergillus flavus group isolated from mixed feed and cereal grain in Spain

A total of 133 samples (mixed feeds and cereal grains) were examined in order to detect the incidence of strains of the Aspergillus flavus group. The ability to produce aflatoxin was tested in all strains isolated on cracked rice, aflatoxin-producing-ability (APA) medium and glucose-yeast extract agar (GYA) medium. Ten out of the 67 isolations were aflatoxin-producing strains in rice and GYA medium; only three of them were aflatoxin-positive on the APA test. Of those isolated 95% were identified as A. flavus. The GYA medium is the most efficient and easiest way to detect B₁, B₂, G₁ and G₂ aflatoxin-producing-strains.