Aflatoxins (AF) are a major problem in broiler production and are significant economic and public health burdens worldwide. A commercial sodium bentonite (Na-B) adsorbent was used to prevent the effect of AF [50 µg of aflatoxin B₁ (AFB₁)/kg of feed] in broiler productivity, biochemical parameters, macroscopic and microscopic liver changes, and AFB₁ liver residues. The influence of Na-B (0.3%) and monensin (MON, 100 mg/kg), alone or in combination, was investigated in depth. The dietary treatments were as follows: treatment (T) 1: basal diet (B); T2: B + MON; T3: B + Na-B; T4: B + Na-B + MON; T5: B + AFB₁; T6: B + AFB₁ + Na-B + MON; T7: B + AFB₁ + MON; T8: B + AFB₁ + Na-B. Birds were fed dietary treatments for 28 d (d 18 to 46). No significant differences (P < 0.05) were observed among treatments with respect to broiler performance, biochemical parameters, or relative liver weights. With the exception of T8, all livers showed histopathological alterations, with accumulation of fat vacuoles. The normal appearance of livers from T8 showed the protective effect of Na-B against aflatoxicosis. The residual AFB₁ levels in livers from T5 to T8 ranged from 0.2 to 1.0 ng/g and were higher in livers from T6 (P < 0.05). Results of this study indicate a competition between AFB₁ and MON for adsorption sites on Na-B when feed contains low levels of the toxin, indicating a nonselective adsorption capacity of this particular Na-B. In addition, significant levels of AFB₁ in livers indicate that this determination is an important technique not only for diagnosis of aflatoxicosis in broilers, but also for quality control of avian products.

Synthetic zeolites (NaX, NaY, NaA, and CaA) were evaluated in vitro for their ability to sorb aflatoxin (AF) B1 from an aqueous solution. Zeolite NaA (ZN) was selected to be tested in vivo because of its high affinity and its stable association with AFB1. This sorbent was incorporated into diets (1%) containing 2.5 mg/kg AFB1. Male broiler chicks from 21 to 42 d of age received ad libitum access to their respective diets and water. When compared with controls, BW gains were lower (P < 0.05) for broilers that were fed AF in their diets. No differences were found between the BW gains of chicks fed diets without AF and those of chicks fed AF + ZN, indicating almost total protection against the effects caused by AF. Liver weights were considerably higher in chicks fed a diet containing AF, compared with those of controls, nevertheless, no significant differences were found in feed:gain ratio among the groups. The findings of this research suggest that ZN can counteract some of the toxic effects of AF in growing broiler chicks.

In vitro studies indicated that a sodium bentonite (SB) from southern Argentina had a high ability to sorb aflatoxin B1 (AFB1) from aqueous solution. We evaluated this compound for its ability to reduce the effects of total aflatoxins (AF; 5 mg AFB1/kg) in the diet of growing broiler chickens from 30 to 52 d of age. The diets were amended with 0.3% Argentinean SB to determine the effect of this compound during aflatoxicosis. When compared with the controls, BW gains were significantly (P < 0.05) lower for broilers fed diets containing AF alone (1,865 vs. 1,552 g). No differences were found between the BW gains of broiler chickens fed diets without AF (1,785 g) and those of chickens fed AF + SB (1,809 g). These results suggest that effects of AF treatment were ameliorated when SB was used in the broiler chick diets. The AF significantly (P < 0.05) decreased feed efficiency. Liver, kidney, and pancreas relative weights increased in chickens fed the diet containing AF alone. Alterations in the levels of serum total protein, albumin (ALB), and globulins (GLOB) were observed for AF diets, and moderate protection was provided by the sorbent. The ALB:GLOB ratio decreased in both groups of birds fed with the AF-contaminated diet, and we observed a moderate increase in this ratio by 0.3% addition of SB. The histopathological findings in liver sections of broiler fed diets with AF + SB indicated a nonprotective effect of this adsorbent, because a moderate hepatic steatosis was observed.

Sodium bentonite (SB) was evaluated for its ability to reduce the deleterious effects of fumonisin B1 (FB1) and aflatoxin B1 (AFB1) in broiler diets. It was incorporated into the diets (0.3%) containing 2.5 mg/kg AFB1, 200 mg/kg FB1, or a combination of 2.5 mg/kg AFB1 and 200 mg/kg FB1. Aflatoxin B1 significantly diminished body weight gain, whereas FB1 or the combination of FB1 and SB had no effect. Addition of SB in the diets significantly diminished the inhibitory effects of dietary AFB1. Feeding AFB1 alone caused significant increases in the relative weights of most observed organs. Feeding FB1 alone did not alter relative weights of any organs. In the combined diet (AFB1 plus FB1) relative weights of the liver, kidney, gizzard, and spleen were increased. Addition of SB to the diet containing AFB1 diminished the relative weights of liver, kidney, and spleen. Addition of SB to diets containing AFB1 and FB1 only decreased liver weights. In relation to the control, lower serum levels of total protein, albumin, and globulins were observed for all AFB, containing diets without SB addition, whereas all other treatments were not altered. Livers of birds fed diets containing AFB1 and a combination of AFB1 and FB1 were enlarged, yellowish, friable, and had rounded borders. The histopathology of them, stained with hematoxylin and eosin, showed multifocal and varied cytoplasmatic vacuolization with perilobular location. Incorporation of SB reduced the incidence and severity of the hepatic histopathology changes associated with aflatoxicosis.

Clay feed additives have been increasingly incorporated into animal diets to prevent aflatoxicosis. Due to the nonselective nature of the binding interaction, many important components of the diets could also be made unavailable because of these feed additives. The anticoccidial monensin (MON) could also be sequestered by these clays. The use of sodium bentonite (Na-B) from a mine in the province of Mendoza, Argentina, was investigated as a sequestering agent to prevent the effects of 100 µg/kg of dietary aflatoxin B(1) (AFB(1)). In vitro studies demonstrated that the above Na-B was a good candidate to prevent aflatoxicosis. They also showed that MON competes with AFB(1) for the adsorption sites on the clay surface and effectively displaces the toxin when it is in low concentration. Even though the levels of MON in diets, approximately 55 mg/kg, are high enough to not be significantly changed as a consequence of the adsorption, they can further affect the ability of the clays to bind low levels of AFB(1). An in vivo experiment carried out with poultry showed that 100 µg/kg of AFB(1) does not significantly change productive or biochemical parameters. However, liver histopathology not only confirmed the ability of this particular Na-B to prevent aflatoxicosis but also the decrease of this capacity in the presence of 55 mg/kg of MON. This is the first report stressing this fact and further research should be performed to check if this behavior is a characteristic of the assayed Na-B or of this type of clay. On the other hand, the presence of MON should also be taken into account when assaying the potential AFB(1) binding ability of a given bentonite.