Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be contaminated by several exometabolites of mycotoxigenic fungi that increase and diversify the risk of mycotoxin exposure in ruminants compared to swine and poultry that have less varied diets. Evidence suggests the greatest exposure for ruminants to some regulated mycotoxins (aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone) and to many other secondary metabolites produced by different species of Alternaria spp. (e.g., AAL toxins, alternariols, tenuazonic acid or 4Z-infectopyrone), Aspergillus flavus (e.g., kojic acid, cyclopiazonic acid or β-nitropropionic acid), Aspergillus fuminatus (e.g., gliotoxin, agroclavine, festuclavines or fumagillin), Penicillium roqueforti and P. paneum (e.g., mycophenolic acid, roquefortines, PR toxin or marcfortines) or Monascus ruber (citrinin and monacolins) could be mainly related to forage contamination. This review includes the knowledge of mycotoxin occurrence reported in the last 15 years, with special emphasis on mycotoxins detected in forages, and animal toxicological issues due to their ingestion. Strategies for preventing the problem of mycotoxin feed contamination under farm conditions are discussed.

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Review on Mycotoxin Issues in Ruminants: Occurrence in Forages, Effects of Mycotoxin Ingestion on Health Status and Animal Performance and Practical Strategies to Counteract Their Negative Effects

Traditional uses, phytochemistry and pharmacology of asafoetida (Ferula assa-foetida oleo-gum-resin)—A review

Aflatoxins are secondary fungal metabolites that contaminate agricultural commodities and can cause sickness or death in humans and animals. Risk of aflatoxin contamination of food and feed in Africa is increased due to environmental, agronomic and socio-economic factors. Environmental conditions especially high humidity and temperature favour fungal proliferation, but also drought conditions increase risk of aflatoxin contamination. Low-input farming practices compound fungal and aflatoxin contamination of crops. The socio-economic and food security status of the majority of inhabitants of sub-Saharan Africa leaves them few options for choosing low-risk and high quality products. Several technologies have been tested in Africa to reduce aflatoxin risk. Field management practices that increase yields can reduce the risk of aflatoxin development. They include use of resistant varieties, crop rotation, well-timed planting, weed control, pest control especially control of insect pests and avoiding drought and nutritional stress through fertilization and irrigation. Measures to stop the infection process by controlling the aflatoxin causing fungi in the field are achieved through use of pesticides and atoxigenic fungi to competitively displace toxigenic fungi, and timely harvest. Post-harvest interventions that reduce aflatoxin include rapid and proper drying, proper transportation and packaging, sorting, cleaning, drying, smoking, post harvest insect control, and the use of botanicals or synthetic pesticides as storage protectants. Another approach is to reduce the frequent consumption of ‘high risk’ foods (especially maize and groundnut) by consuming a more varied diet, and diversifying the diet into less risky staples like sorghum and millet. Chemo-preventive measures that can reduce aflatoxin effect include daily consumption of chlorophyllin or oltipraz and incorporating hydrated sodium calcium alumino-silicates into the diet. Reduction and detoxification of aflatoxin is often achieved physically (sorting, physical segregation, flotation etc.), chemically (e.g. calcium hydroxide, ammonia) and microbiologically by incorporating pro-biotics or lactic acid bacteria into the diet. Millers can use blending of less and more contaminated products to reduce the overall risk. There is need for efficient monitoring and surveillance with cost-effective sampling and analytical methods to reduce risk in Africa. Public education and awareness can sensitize the population on aflatoxin risk and its management.

	 

	Key words: Aflatoxin, Sub-Saharan Africa, control measures.

Aflatoxin control and prevention strategies in key crops of Sub-Saharan Africa

Preparation of alginate nanocapsules containing turmeric oil

Aflatoxin B1 (AFB1) is one of the most harmful mycotoxins in animal production and food industry. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 65 samples were screened from various sources with vast microbial populations using a newly developed medium containing coumarin as the sole carbon source. Twenty five single-colony bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screen. Isolate 35-3, obtained from tapir feces and identified to be Stenotrophomonas maltophilia, reduced AFB1 by 82.5% after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of isolate 35-3 was able to degrade AFB1 effectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Activity was reduced to 60.8% and 63.5% at 20 °C and 30 °C, respectively, from 78.7% at 37 °C. The highest degradation rate was 84.8% at pH 8 and the lowest was only 14.3% at pH 4.0. Ions Mg2+ and Cu2+ were activators for AFB1 degradation, however，ion Zn2+ was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the degradation activity of the culture supernatant. The results indicated that the degradation of AFB1 by S. maltophilia 35-3 was enzymatic and could have a great potential in industrial applications.

https://www.mdpi.com/1422-0067/9/8/1489/pdf

Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium

Effect of some chemical and herbal compounds on growth of Aspergillus parasiticus and aflatoxin production

Efficacy of heat treatment and sun drying of aflatoxin-contaminated feed for reducing the harmful biological effects in sheep

Estimation of aflatoxin content of several livestock feeds and feed ingredients indicated the presence of aflatoxin (10–56 ppb AF B1) in compounded feeds. Samples of groundnut cake had aflatoxin content of 279 ppb (AF B1) and 39 ppb (AF B2) and samples of wheat bran, rice bran and rice polish showed negligible aflatoxin content. Fodder samples of maize, sorghum, gram husk and coffee husk contained no detectable aflatoxin. Storage studies with different moisture levels and duration of storage showed a trend of increased mold growth at moisture level above 15% and was highest during 7–21 days of storage (3.66–3.83 logCFU/g). Feeds stored in air-tight containers at 0% moisture level showed no fungal growth and at below 7.5% moisture level there was minimum fungal growth (3.18–4.18 logCFU/g). The aflatoxin (B1) production was maximum (P<0.05) between 12.5–17.5% moisture level upto 14 days of storage. The average aflatoxin (B1) production was highest (P<0.05) at 15% moisture level and 28 days of feed storage (15 ppb) and was well within the permissible limit of 20–30 ppb. At 15% moisture level for 14 days of storage the fungal growth and aflatoxin (B1) production was maximum (P<0.01) in flake (unground) form as compared to the ground form. The results of this study suggested that the moisture level in feeds should be less than 10% for safe storage and feeds with above 12.5% moisture level should be used within a week period or should be dried for safe storage.

Screening for Aflatoxin and Effect of Moisture, Duration of Storage and Form of Feed on Fungal Growth and Toxin Production in Livestock Feeds

Utilization of dietary minerals and blood biochemical values in lambs fed hydrated sodium calcium alumino silicate sorbent material at supplementary level

Studies on influence of different storage conditions and type of bag material on aflatoxin production in animal feeds were conducted. Storage of groundnut cake (GNC) and maize with 12 per cent moisture level in open plastic containers under godown conditions for 28 days period showed a significant (P<0.01) increase in the aflatoxin (B) content from 10±0.50 to 70±3,5 ppb in GNC and 8±0.76 to 34±3.3 ppb in maize. Storage studies with jute/gunny and HDPE bags showed higher fungal spore count (31–58 x 104 CFU/g) and significantly (P<0.05) higher aflatoxin production (385±15 to 393±2 ppb) in feeds stored in gunny (jute) bags as compared to HDPE bags (27–43 x 104 CFU/gm & 343±4 to 360±21 ppb) at 12.5–15 per cent moisture level. The spore count and the aflatoxin production (6–9 x 104 CFU/g & 20–25 ppb) were minimum in both the type of bags at 7.5 per cent moisture level and was uniformly increased in both the bags at 10 per cent moisture level (33–76 ppb & 35–68 ppb). It is suggested that below 10 per centmoisture level is safe for feed storage provided further entry of moisture is not there. At above 12.5 per cent moisture level, storing feeds in HDPE bags could considerably reduce fungal growth and aflatoxin production but drying and storing would be more appropriate and safe.

R.U. Suganthi

Papers

Effect of some chemical and herbal compounds on growth of Aspergillus parasiticus and aflatoxin production

Efficacy of heat treatment and sun drying of aflatoxin-contaminated feed for reducing the harmful biological effects in sheep

Screening for Aflatoxin and Effect of Moisture, Duration of Storage and Form of Feed on Fungal Growth and Toxin Production in Livestock Feeds

Utilization of dietary minerals and blood biochemical values in lambs fed hydrated sodium calcium alumino silicate sorbent material at supplementary level

Influence of Storage Condition, Bag Material and Duration of Feed Storage on Aflatoxin Production