Efficacy of clay minerals for controlling aflatoxin B1 toxicity in commercial broilers

Aflatoxin occurrence in poultry feed causes aflatoxicosis in birds and poses health hazards to the consumers. Aflatoxin B1 (AfB1) is the most predominant and toxic metabolite that is controlled through addition of argillaceous clays as non-nutritive additives. Non-smectitic indigenous clay reserves need testing as AfB1 adsorbent. With detailed mineral and adsorption characteristics, three indigenous non-smectitic clays: (i) palygorskite, (ii) palygorskite-smectite mix, and (iii) interstratified smectite with hydroxy interlayered smectite were tested against 250 ??g kg-1 AfB1 contamination in a poultry feeding trial with three replications at 1% and 2% (w/w) with positive and negative controls. A total of 330 Ross-308 male broiler chicks, initially reared on clean feed under controlled conditions of light and humidity, were distributed into eleven treatment combinations in a completely randomized design with 30 birds in each treatment on an equal weight basis with three replications at day 14 and fed on experimental feeds for three weeks. Three birds from each pen were randomly slaughtered at day 35 and for each replicated treatment, body weight gain, feed intake, and internal organs weight and morphology were recorded. AfB1 contamination reduced weight gain (p 0.0001), feed conversion ratio (p 0.0001) and feed intake (p 0.0001) while clays addition in the toxin feed effectively controlled AfB1 toxicity as suggested by improved body weight, weight gain rate and feed consumption compared to the toxin fed birds. The liver morphology was comparatively better in palygorskite-smectite mix treatment when applied at 1% and the darkish colour was also improved with addition of the clay in the toxin feed. AfB1 feeding caused a 75% reduction in weight gain compared to the clean feed. Palygorskite and palygorskite-smectite mix clays were better than interstratified clay in increasing weight gain and caused a 60% and 65% increase over toxin feed treatment when applied at 1% and 2%, respectively. In conclusion, the indigenous clay sources overall and palygorskite-smectite mix in particular has the potential for use as a mycotoxin binder for controlling AfB1 incidence in poultry.