Feed additives containing sequestrant clay minerals and inactivated yeast reduce aflatoxin excretion in milk of dairy cows

Abstract

The objective was to evaluate the efficacy of 2 dietary mycotoxin sequestrants, Toxy-Nil (TN) or Unike Plus (UP), in reducing aflatoxin (AF) M 1 concentrations in milk of dairy cows challenged with dietary AF. Thirtytwo mid-lactation Holstein cows were blocked by parity, days in milk, and milk yield and were randomly assigned within block to receive one of the following treatments:(1) 2.8 mg of AF/cow per d (positive control, PC), (2) 2.8 mg of AF + 100 g of TN/cow per d, (3) 2.8 mg of AF + 100 g of UP/cow per d, or (4) no AF and no additives (negative control, NC). For 7 d, treatments, dispersed in 150 g of sweet feed carrier, were top-dressed twice daily by mixing into the top portion of the TMR at each feeding. After the experimental period, cows were fed the NC diet and clearance of AFM 1 via milk was monitored for 7 d. Feed and water were available ad libitum throughout the trial. Treatments had no effect on feed intake, milk yield, milk composition, or milk somatic cell count. Relative intake of AF was similar among PC, TN, and UP, averaging 106.5, 107.6, and 102.5 ± 2.9 μg/kg of diet dry matter, respectively. Relative intake of mycotoxin sequestrants was similar between TN and UP, averaging 0.4 and 0.4 ± 0.1% of diet dry matter, respectively. Concentration and mass of AFM 1 secreted in milk and in urine were similar between TN and UP, but were lower than PC; concentrations in milk averaged 0.2, 0.3, and 0.6 ± 0.1 μg/kg, respectively, and mass secreted in milk averaged 8. 1, 9.8, and 20.5 ± 1.7 μg/d. Concentrations in urine averaged 6.9, 7.4, and 14.2 ± 1.5 μg/L, respectively, and mass secreted in urine averaged 225.7, 250.8, and 521.6 ± 53.1 μg/d. Likewise, concentration and mass of free AF excreted in feces were similar between TN and UP, but were lower than PC; concentrations averaged 7.7, 8.9, and 12.4 ± 0.6 μg/kg, respectively, and mass excreted averaged 57.8, 69.6, and 95.6 ± 4.8 μg/d. Transfer of AF from feed to AFM 1 in milk was reduced by 63 and 52%, and in urine, by 57 and 52% for TN and UP, respectively. Transfer of AF from feed to free AF in feces was reduced by 38 and 26% for TN and UP, respectively. The clearance rate of AFM 1 in milk did not differ among PC, TN, and UP (46.1, 66.5, and 50.0 ± 6.7%/d, respectively). Results indicate that dietary inclusion of 100 g of TN or UP significantly reduced AFM 1 in milk of cows consuming TMR containing approximately 105 μg of AF/kg of diet dry matter. Results also suggest that both TN and UP reduced absorption of AF.

Effect of Supplemental Kluyveromyces marxianus and Pichia kudriavzevii on Aflatoxin M1 Excretion in Milk of Lactating Dairy Cows

“…Increasing digestion is a factor that contributes to improving DMI [43]. However, our results were not consistent with others who found no effect on DMI when cows received dietary AFB 1 at 210 to 313 µg/kg and fed supplemental clay or inactivated yeast supplements to bind AFB 1 [28,37]. Mycotoxin binders appear to have a dose-dependent effect on DMI [44].…”

“…These results are consistent with previous reports in that AFB 1 was readily absorbed within the gastrointestinal tract and metabolized in the liver to form AFM 1 , which is quickly excreted into milk or urine. As expected, cows fed AFB 1 secreted substantial quantities of AFM 1 into their milk [35][36][37]. Concentrations of AFM 1 in milk were consistent with those reported by Kutz et al [38], who also fed AFB 1 at about 100 µg/kg of DM, but were markedly higher than those reported by others [13,28], who fed about 75 µg of AF/kg of DM, probably due in part to concentrations of AFB 1 fed.…”

Adverse Effects, Transformation and Channeling of Aflatoxins Into Food Raw Materials in Livestock

“…Following the channeling of AFB 1 in ruminants, the ingested aflatoxins may be degraded, at least in part, to AFL, AFM 1 and many other hydroxylated metabolites by certain rumen microbes or may be sequestered by some rumen fluid components such as chlorophyllin structures as well as bacterial and yeast cell walls (Gallo et al, 2015). The remaining fraction is rapidly adsorbed in the gastro-intestinal tract by passive diffusion and then is extensively metabolized in the liver to AFM 1 , which enters the systemic circulation or is conjugated to glucuronic acid, and afterward excreted via bile, urine or milk (Kuilman et al, 2000;Rodrigues et al, 2019). Obviously, different levels of feed contamination may lead to different carry-over rates, which are also influenced by other physiological factors such the health status of animals including the status of the liver and its enzymatic activities.…”

“…AFB 1 , AFM 1 and AFL have been detected in liver, kidney and muscle tissue of bovine (Kuilman et al, 1998). AFM 1 is excreted via urine at a greater extent than through milk but the physiological factors regulating the relative uptake by kidneys and mammary glands are still unknown (Rodrigues et al, 2019). AFM 1 has been detected in both the milk and urine of cattle and dairy ewes 6 h after AFB 1 ingestion (Helferich et al, 1986;Battacone et al, 2003), and its concentration decreased rapidly after withdrawal of aflatoxin from diets (Rodrigues et al, 2019).…”

“…AFM 1 is excreted via urine at a greater extent than through milk but the physiological factors regulating the relative uptake by kidneys and mammary glands are still unknown (Rodrigues et al, 2019). AFM 1 has been detected in both the milk and urine of cattle and dairy ewes 6 h after AFB 1 ingestion (Helferich et al, 1986;Battacone et al, 2003), and its concentration decreased rapidly after withdrawal of aflatoxin from diets (Rodrigues et al, 2019). Fecal excretion of FB 1 results from a lack of absorption by the GIT or a highly efficient elimination by the biliary system in the form of conjugated metabolites (Yiannikouris and Jouany, 2002;Jouany et al, 2009).…”