Mycopathologia 109: 157-164, 1990. 9 1990 Kluwer Academic Publishers. Printed in Belgium.
157
A mycological and bacteriological survey on feed ingredients and mixed poultry feeds in Reunion island Pascal Bauduret Laboratoire V~tOrinaire Ddpartemental de la R~union, 14, rue du Stade de l'Est, 97490 Sainte-Clotilde, Ile de la R~union, France Accepted: Received 8 July 1988; accepted 28 June 1989
Key words: mixed poultry feeds, fungi, Aspergillus flavus, aflatoxins
Abstract
A survey was carried out in Reunion island to obtain data on the occurrence of fungi, aflatoxigenic strains of Aspergillusflavus, aflatoxins, total aerobic bacteria and salmonellae of 150 samples of mixed poultry feeds and raw materials. These were collected at five farms over a 3-month period during the warm rainy season. White corn and Brazilian soybean meal seemed to present a better microbiological quality than yellow corn and US soybean meal. Mixed poultry feeds presented a high total mold count reflecting the mold flora of raw materials. The most frequent and abundant fungi were Aspergillus flavus, A. glaucus group, Fusarium spp., Penicillium spp., A. candidus, Mucor spp., A. restrictus, Scopulariopsis spp., Cladosporium spp. and A. versicolor. Of the 118 A.flavus strains screened, 42 (35.6~o) were aflatoxigenic. Yellow corn samples were the most frequently contamined with aflatoxigenic strains (54.5 ~o), followed by mixed feeds (44~o). Of the 66 samples tested, 24 (36 ~o) contained aflatoxins (traces to 22 ng/g). A good correlation seemed to exist between presence of at least one aflatoxigenic strain per sample and presence of aflatoxins.
Introduction
Reunion island, a French tropical country in the Indian Ocean, has a well developed poultry husbandry. Mixed feeds are made locally from imported raw materials. Yellow and white corn are from African origin (Kenya, Tanzania, Zimbabwe, Madagascar, Mauritius... ). Soybean meals come from Brazil (pellet-type) or the USA. Mineral and vitamin concentrates originate in France. Because mold contamination can decrease nutritional value of feeds [2] and affect animal
health (mycosis, mycotoxicosis) [ 14] especially in tropical countries where temperature and relative humidity are high, it is necessary to control microbiological quality of feedstuffs. So, a mycological unit was set up in the Veterinary laboratory of Reunion island in 1986. Surveys are regularly done in order to obtain data about fungal occurrence in raw materials and feedstuffs [3]. The following study, carried out in the 1988 warm rainy season, includes an examination of mycoflora, total aerobic bacteria and salmonellae in the samples collected. Aflatoxigenic strains of Aspergillus flavus and aflatoxin contamination
158
Mycological studies
were also investigated. The microbiological quality of raw materials and feedstuffs was evaluated, and results compared with those obtained in other countries.
External mycoflora was determined according to French Standard AFNOR V08-301. A 20 g subsample was placed with glass balls in 180 ml of dilution liquid (1.6 g tryptone; 8.5 g sodium chloride; 2 drops Tween 80; 1000 ml distilled water), and thoroughly mixed on an orbital shaker (400 r.p.m.) for 20 min. Appropriate serial decimal dilutions were made, and for each one, 1 ml was pipetted into 4 sterile disposable petri dishes. M2 agar (2~o malt extract; 0.2~o yeast extract and 1.8 ~o agar) containing 60 #g/ml chloramphenicol (Sigma, St.-Louis, USA) and 50 #g/ml gentamycin sulfate (Sigma) was added to 2 plates. M5 agar (5% malt extract; 0.2~o yeast extract; 5~o sodium chloride and 1.8% agar), also containing antibiotics, was poured in the other 2 plates. One plate of each medium was incubated at 25 ~C, and the others at 35 ~ After 4 to 6 days of incubation, molds were identified and counts were made of individual species and genera. Results were expressed in propagules per gram of sample. Internal mycoflora was determined only on samples of whole corn. From each sample, 50 whole kernels were surface-sterilized for 2 min with sodium hypochloride containing about 1000 p.p.m, available chlorine, and washed twice with sterile water. 25 kernels were plated on M2 agar
Materials and methods
Samples In January, February, and March 1988, samples of yellow and white corn, US and Brazilian soybean meals, concentrates, and mixed poultry feeds were taken at 2 weeks intervals on five farms dispersed over the whole island. The samples were stored at 4 ~ as soon as they were collected, sent to the laboratory and analysed the day after.
Physico-chemicals parameters At the moment of collection, temperature (~ C), and relative humidity (~o) were measured inside each sample respectively with a NOVO Quick Thermometer and a stick hygrometer of HANNA Instruments (HI8565). On arrival at the laboratory, the moisture content of the samples was measured with an infra-red dessicator SARTORIUS at 133 ~
u)
,~
100 T
157
A mycological and bacteriological survey on feed ingredients and mixed poultry feeds in Reunion island Pascal Bauduret Laboratoire V~tOrinaire Ddpartemental de la R~union, 14, rue du Stade de l'Est, 97490 Sainte-Clotilde, Ile de la R~union, France Accepted: Received 8 July 1988; accepted 28 June 1989
Key words: mixed poultry feeds, fungi, Aspergillus flavus, aflatoxins
Abstract
A survey was carried out in Reunion island to obtain data on the occurrence of fungi, aflatoxigenic strains of Aspergillusflavus, aflatoxins, total aerobic bacteria and salmonellae of 150 samples of mixed poultry feeds and raw materials. These were collected at five farms over a 3-month period during the warm rainy season. White corn and Brazilian soybean meal seemed to present a better microbiological quality than yellow corn and US soybean meal. Mixed poultry feeds presented a high total mold count reflecting the mold flora of raw materials. The most frequent and abundant fungi were Aspergillus flavus, A. glaucus group, Fusarium spp., Penicillium spp., A. candidus, Mucor spp., A. restrictus, Scopulariopsis spp., Cladosporium spp. and A. versicolor. Of the 118 A.flavus strains screened, 42 (35.6~o) were aflatoxigenic. Yellow corn samples were the most frequently contamined with aflatoxigenic strains (54.5 ~o), followed by mixed feeds (44~o). Of the 66 samples tested, 24 (36 ~o) contained aflatoxins (traces to 22 ng/g). A good correlation seemed to exist between presence of at least one aflatoxigenic strain per sample and presence of aflatoxins.
Introduction
Reunion island, a French tropical country in the Indian Ocean, has a well developed poultry husbandry. Mixed feeds are made locally from imported raw materials. Yellow and white corn are from African origin (Kenya, Tanzania, Zimbabwe, Madagascar, Mauritius... ). Soybean meals come from Brazil (pellet-type) or the USA. Mineral and vitamin concentrates originate in France. Because mold contamination can decrease nutritional value of feeds [2] and affect animal
health (mycosis, mycotoxicosis) [ 14] especially in tropical countries where temperature and relative humidity are high, it is necessary to control microbiological quality of feedstuffs. So, a mycological unit was set up in the Veterinary laboratory of Reunion island in 1986. Surveys are regularly done in order to obtain data about fungal occurrence in raw materials and feedstuffs [3]. The following study, carried out in the 1988 warm rainy season, includes an examination of mycoflora, total aerobic bacteria and salmonellae in the samples collected. Aflatoxigenic strains of Aspergillus flavus and aflatoxin contamination
158
Mycological studies
were also investigated. The microbiological quality of raw materials and feedstuffs was evaluated, and results compared with those obtained in other countries.
External mycoflora was determined according to French Standard AFNOR V08-301. A 20 g subsample was placed with glass balls in 180 ml of dilution liquid (1.6 g tryptone; 8.5 g sodium chloride; 2 drops Tween 80; 1000 ml distilled water), and thoroughly mixed on an orbital shaker (400 r.p.m.) for 20 min. Appropriate serial decimal dilutions were made, and for each one, 1 ml was pipetted into 4 sterile disposable petri dishes. M2 agar (2~o malt extract; 0.2~o yeast extract and 1.8 ~o agar) containing 60 #g/ml chloramphenicol (Sigma, St.-Louis, USA) and 50 #g/ml gentamycin sulfate (Sigma) was added to 2 plates. M5 agar (5% malt extract; 0.2~o yeast extract; 5~o sodium chloride and 1.8% agar), also containing antibiotics, was poured in the other 2 plates. One plate of each medium was incubated at 25 ~C, and the others at 35 ~ After 4 to 6 days of incubation, molds were identified and counts were made of individual species and genera. Results were expressed in propagules per gram of sample. Internal mycoflora was determined only on samples of whole corn. From each sample, 50 whole kernels were surface-sterilized for 2 min with sodium hypochloride containing about 1000 p.p.m, available chlorine, and washed twice with sterile water. 25 kernels were plated on M2 agar
Materials and methods
Samples In January, February, and March 1988, samples of yellow and white corn, US and Brazilian soybean meals, concentrates, and mixed poultry feeds were taken at 2 weeks intervals on five farms dispersed over the whole island. The samples were stored at 4 ~ as soon as they were collected, sent to the laboratory and analysed the day after.
Physico-chemicals parameters At the moment of collection, temperature (~ C), and relative humidity (~o) were measured inside each sample respectively with a NOVO Quick Thermometer and a stick hygrometer of HANNA Instruments (HI8565). On arrival at the laboratory, the moisture content of the samples was measured with an infra-red dessicator SARTORIUS at 133 ~
u)
,~
100 T
