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Clay minerals as sorbents for mycotoxins in lactating goat’s diets: Intake, digestibility, blood chemistry, ruminal fermentation, milk yield and composition, and milk aflatoxin M1 content

Gouda, G.A., Khattab, H.M., Abdel-Wahhab, M.A., Abo El-Nor, S.A., El-Sayed, H.M., Kholif, S.M.
Small ruminant research 2019 v.175 pp. 15-22
Trifolium alexandrinum, additives, aflatoxin B1, aflatoxin M1, ammonium nitrogen, bentonite, blood glucose, clay, crossbreds, crude protein, diet, digestibility, energy, fatty acid composition, feces, feed conversion, goats, hay, lactation, lactose, milk, milk composition, milk yield, montmorillonite, neutral detergent fiber, nutrient intake, nutritive value, organic matter, rumen, rumen fermentation, sorbents, total solids, volatile fatty acids, zearalenone
We assessed the effect of bentonite and montmorillonite, as sorbents, on feed utilization, lactation performance, and mycotoxin concentrations in milk. During the first week of lactation, fifteen lactating crossbred (Nubian × Baladi) goats weighing 20.5 ± 0.5 kg were randomly assigned to three treatments (five does each) in a complete randomized design for a 90-day trial with repeated measures. Goats were stratified according to parity and expected average milk yield to be fed daily with one of three diets: a basal diet containing 600 g concentrates and 400 g berseem hay (Control treatment), or the control diet supplemented with bentonite clay at 20 g/kg dry matter (DM) concentrate (Bentonite treatment), or the control diet supplemented with montmorillonite clay at 20 g/kg DM concentrate (Montmorillonite treatment). The basal diet used in all treatments was naturally contaminated with aflatoxin B1 (AFB1) at 56.7 μg/kg and zearalenone (ZEN) at 112.5 μg/kg. Additives had no effect on nutrient intake but increased (P < 0.05) the digestibility of DM, organic matter, crude protein, ether extract, non-fibre carbohydrates and neutral detergent fibre. The montmorillonite diet had a greater (P < 0.05) nutritive value than the bentonite and control diets. Does that received the bentonite treatment had greater (P < 0.001) ruminal ammonia-N concentration at 6 h after feeding than those received the control or the montmorillonite treatment. Feeding the bentonite and montmorillonite diets increased (P < 0.001) the total N concentration in the rumen. Moreover, montmorillonite treatment increased (P < 0.01) ruminal total volatile fatty acid concentrations at 3 and 6 h after feeding, however, AFB1 and ZEN concentrations were decreased (P < 0.05) in the rumens of the montmorillonite does compared with the control does. Additives increased (P < 0.01) the concentrations of plasma glucose compared with the control diet. Without affecting the daily yields of milk or energy-corrected milk, additives increased (P < 0.05) the concentrations of total solids, solids-non-fat, protein, lactose and energy in milk. Despite an increased concentration of faecal AFB1 (P < 0.001), montmorillonite and bentonite treatments decreased the concentrations of aflatoxin M1(AFM1) in milk (P < 0.001) and ZEN in faeces. It was concluded that the addition of bentonite or montmorillonite at 20 g/kg DM concentrate (equal to 1.2% of total diet DM) in the diets of lactating does enhanced nutrient digestibility and milk composition and decreased the content of AFM1 in milk, resulting in improving the health benefit of milk for consumers.