In vitro efficacy of cetyltrimethylammonium bromide (CETAB)-modified nano-montmorillonite against aflatoxin B1 associated toxicity and methanogenesis.

Background: Modified nano-montmorillonite is gaining attention as a feed additive for its benefits on ruminal fermentation. Chemical and mechanical methods were used to modify montmorillonite. Cetyltrimethylammonium bromide (CETAB) was utilized for chemical modification, while grounding was carried out to achieve the desired nanoscale particle size, resulting in the formation of the nanoscale powder known as MNM. Impacts of MNM supplementation on a basal diet, either contaminated with aflatoxin B1 (AFB1) or not at a level of 20 ppb were tested. Treatments included control (no supplements), a diet with 5 g per kilogram of dry matter (DM) of natural montmorillonite (NM), and diets with MNM at two doses, 0.5 (low) and 1 (high) grams per kilogram DM.

Results: The MNM showed better physicochemical traits than NM clay, including narrower particle size range, higher cation exchange capacity (CEC), greater specific surface area (SSA), and more functional groups. A significant linear decreasing effect (P < 0.05) of MNM addition on methane (CH) production was observed by the increasing level of the MNM clay. The control diet contaminated with AFB1 resulted in lower fiber degradability than the other treatments (P < 0.05). No variations were observed in ruminal protozoal counts by both clay supplementations, although there was a noticeable trend (P = 0.08) towards reduced protozoal populations due to AFB1 contamination. AFB1-contaminated diets showed indications of reduced (P < 0.05) levels of total volatile fatty acids (VFA), and concentrations of butyrate and propionate (P < 0.05), alongside shifts towards elevated (P = 0.006) acetate levels, while the low dose of MNM exhibited higher (P < 0.01) propionate concentrations than the other treatments.

Conclusion: These findings underscored the anti-methanogenic properties and the favorable impacts of MNM in mitigating the adverse impacts of AFB1on ruminal fermentation and nutrient degradability.