Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma del Estado de México, Toluca, Estado de Mexico, Mexico.
Centro Nacional de Investigación Disciplinaria en Fisiología y Mejoramiento Animal, INIFAP, 76280, Ajuchitlan, Queretaro, Mexico.
Environ Sci Pollut Res Int. 2019 Apr;26(10):9992-9999. doi: 10.1007/s11356-019-04400-1. Epub 2019 Feb 9.
Environmental impact of livestock production has received a considerable public scrutiny because of the adverse effects of nutrient run-offs, primarily N and P, from agricultural land harboring intensive energy livestock operations. Hence, this study was designed to determine the efficacy of dietary phytase supplementation on fermentation of a sorghum grain-based total mixed ration (TMR) using a ruminal in vitro digestion approach. Phytase was supplemented at three doses: 0 (control), 540 (P540), and 720 (P720) g/t dry matter, equivalent to 0, 2.7 × 10, and 3.6 × 10 CFU/t DM, respectively. Compared to P720 and the control, gas production was higher for P540 after 12 h (P = 0.02) and 24 h (P = 0.03) of fermentation suggesting a higher microbial activity in response to phytase supplementation at lower phytase levels. Correspondingly, dry matter degradability was found to have improved in P540 and P720 compared to the control by 13 and 11% after 24 h of incubation (P = 0.05). For ammonia nitrogen (NH-N), a tendency towards lower values was only observed for P540 at 24 h of fermentation (P = 0.07), while minimal treatment effects were observed at other fermentation times. The concentrations of total volatile fatty acids (VFA) were higher (P < 0.05) after 48 h of fermentation for P540 and P720 compared to the control (P = 0.03) by 10% and 14%, respectively. Ruminal acetate tended towards higher values in the presence of phytase after 12 h of fermentation (P = 0.10), but towards lower values after 24 h of fermentation (P = 0.02), irrespective of the phytase dose applied. A trend towards lower ruminal propionate levels was observed in the presence of phytase after 6 h (P = 0.10) and 12 h (P = 0.06) of fermentation, while no effects were found at other fermentation times. In conclusion, phytase supplementation has the potential to improve metabolic energy activity of rumen microorganisms and the use of feed constituents. Thus, phytase supplementation could help to reduce environmental contamination in areas of ruminant production.
畜牧业生产对环境的影响受到了相当大的公众关注，因为农业土地上的养分流失（主要是氮和磷）对集约化能源畜牧业的不利影响。因此，本研究旨在确定日粮植酸酶添加对利用瘤胃体外消化法发酵高粱谷物全混合日粮（TMR）的效果。植酸酶分别添加 3 个剂量：0（对照）、540（P540）和 720（P720）g/t 干物质，分别相当于 0、2.7×10 和 3.6×10 CFU/t DM。与 P720 和对照相比，P540 在发酵 12 和 24 小时后的气体产量更高（P=0.02 和 P=0.03），这表明在较低的植酸酶水平下，微生物对植酸酶添加的反应更高。相应地，与对照相比，P540 和 P720 在 24 小时的孵育后，干物质降解率分别提高了 13%和 11%（P=0.05）。对于氨态氮（NH-N），仅在发酵 24 小时时，P540 观察到有降低的趋势（P=0.07），而在其他发酵时间观察到最小的处理效果。发酵 48 小时后，与对照相比，P540 和 P720 的总挥发性脂肪酸（VFA）浓度分别升高了 10%（P<0.05）和 14%（P=0.03）。在发酵 12 小时时，添加植酸酶后瘤胃乙酸的含量趋于更高（P=0.10），但在发酵 24 小时时，其含量趋于更低（P=0.02），而与添加的植酸酶剂量无关。在发酵 6 和 12 小时时，添加植酸酶后瘤胃丙酸水平有降低的趋势（P=0.10 和 P=0.06），而在其他发酵时间则没有发现这种影响。总之，植酸酶添加具有提高瘤胃微生物代谢能量活性和利用饲料成分的潜力。因此，植酸酶添加可以帮助减少反刍动物生产地区的环境污染。
