Department of Animal Sciences, University of Florida, Gainesville 32611.
Department of Animal Sciences, University of Florida, Gainesville 32611; Division of Food and Animal Science, Kentucky State University, Frankfort 40601.
J Dairy Sci. 2018 Apr;101(4):3008-3020. doi: 10.3168/jds.2017-13678. Epub 2018 Feb 7.
The study was conducted to examine the effect of supplementing bentonite clay with or without a Saccharomyces cerevisiae fermentation product (SCFP; 19 g of NutriTek + 16 g of MetaShield, both from Diamond V, Cedar Rapids, IA) on the performance and health of dairy cows challenged with aflatoxin B (AFB). Twenty-four lactating Holstein cows (64 ± 11 d in milk) were stratified by parity and milk production and randomly assigned to 1 of 4 treatment sequences. The experiment had a balanced 4 × 4 Latin square design with 6 replicate squares, four 33-d periods, and a 5-d washout interval between periods. Cows were fed a total mixed ration containing 36.1% corn silage, 8.3% alfalfa hay, and 55.6% concentrate (dry matter basis). Treatments were (1) control (no additives), (2) toxin (T; 1,725 µg of AFB/head per day), (3) T + clay (CL; 200 g/head per day; top-dressed), and (4) CL+SCFP (CL+SCFP; 35 g/head per day; top-dressed). Cows were adapted to diets from d 1 to 25 (predosing period) and then orally dosed with AFB from d 26 to 30 (dosing period), and AFB was withdrawn from d 31 to 33 (withdrawal period). Milk samples were collected twice daily from d 21 to 33, and plasma was sampled on d 25 and 30 before the morning feeding. Transfer of ingested AFB into milk aflatoxin M (AFM) was greater in T than in CL or CL+SCFP (1.65 vs. 1.01 and 0.94%, respectively) from d 26 to 30. The CL and CL+SCFP treatments reduced milk AFM concentration compared with T (0.45 and 0.40 vs. 0.75 µg/kg, respectively), and, unlike T, both CL and CL+SCFP lowered AFM concentrations below the US Food and Drug Administration action level (0.5 µg/kg). Milk yield tended to be greater during the dosing period in cows fed CL+SCFP compared with T (39.7 vs. 37.7 kg/d). Compared with that for T, plasma glutamic oxaloacetic transaminase concentration, indicative of aflatoxicosis and liver damage, was reduced by CL (85.9 vs. 95.2 U/L) and numerically reduced by CL+SCFP (87.9 vs. 95.2 U/L). Dietary CL and CL+SCFP reduced transfer of dietary AFB to milk and milk AFM concentration. Only CL prevented the increase in glutamic oxaloacetic transaminase concentration, and only CL+SCFP prevented the decrease in milk yield caused by AFB ingestion.
本研究旨在探讨补充膨润土和/或酿酒酵母发酵产物（SCFP；19 克 NutriTek + 16 克 MetaShield，均来自 Diamond V，爱荷华州锡达拉皮兹）对受黄曲霉毒素 B（AFB）挑战的奶牛生产性能和健康的影响。24 头泌乳荷斯坦奶牛（泌乳期 64±11 天）按胎次和产奶量分层，随机分为 4 种处理序列中的 1 种。该实验采用平衡 4×4 拉丁方设计，有 6 个重复方，4 个 33 天期和 5 天的冲洗间隔期。奶牛饲喂含有 36.1%玉米青贮、8.3%苜蓿干草和 55.6%浓缩物（干物质基础）的全混合日粮。处理方法为（1）对照组（无添加剂），（2）毒素（T；每天每头 1725µg AFB），（3）T+黏土（CL；每天每头 200g；表面撒施），（4）CL+SCFP（CL+SCFP；每天每头 35g；表面撒施）。奶牛从第 1 天到第 25 天适应日粮（预饲期），然后从第 26 天到第 30 天口服 AFB（给药期），从第 31 天到第 33 天停止 AFB（撤药期）。从第 21 天到第 33 天每天两次采集牛奶样品，在第 25 天和第 30 天早上喂料前采集血浆样品。从第 26 天到第 30 天，与 CL 或 CL+SCFP 相比，T 组中摄入的 AFB 转移到牛奶中的黄曲霉毒素 M（AFM）更多（分别为 1.65%、1.01%和 0.94%）。CL 和 CL+SCFP 处理组与 T 相比降低了牛奶 AFM 浓度（分别为 0.45 和 0.40 与 0.75µg/kg），并且与 T 不同，CL 和 CL+SCFP 均降低了 AFM 浓度低于美国食品和药物管理局的行动水平（0.5µg/kg）。与 T 相比，在 CL+SCFP 组奶牛的产奶量在给药期有增加的趋势（39.7 与 37.7kg/d）。与 T 相比，CL 降低了指示黄曲霉毒素中毒和肝损伤的血浆谷氨酸草酰乙酸转氨酶浓度（85.9 与 95.2U/L），并且 CL+SCFP 数值上也降低了（87.9 与 95.2U/L）。日粮 CL 和 CL+SCFP 降低了日粮 AFB 向牛奶中的转移和牛奶 AFM 浓度。只有 CL 防止了谷氨酸草酰乙酸转氨酶浓度的升高，只有 CL+SCFP 防止了因摄入 AFB 而导致的产奶量下降。
