Can perfluoroalkyl acids biodegrade in the rumen simulation technique (RUSITEC)?

Environmental Sciences Europe

Table 2 Fermentation characteristics of PFAA-free hay and PFAA hay with low and high PFAA levels

Item	PFAA level	PFAA-free hay^c (day 7–12)	PFAA hay (day 13)	SEM	P value^d
pH	Low^a	6.87 ± 0.03	6.77 ± 0.08	1.60	≤0.05
pH	High^b	6.86 ± 0.02	6.69 ± 0.09	2.16	≤0.05
Redox potential, mV	Low^a	−271 ± 19	−309 ± 30	29.7	≤0.05
Redox potential, mV	High^b	−267 ± 24	−298 ± 27	31.9	≤0.05
Ammonia, mmol/l	Low^a	11.77 ± 0.50	9.82 ± 1.12	1.87	0.09
Ammonia, mmol/l	High^b	11.81 ± 0.61	6.85 ± 0.42	0.91	≤0.05
Volatile fatty acids (VFA), mmol/day
Total VFA	Low^a	22.32 ± 1.00	25.90 ± 0.78	1.60	≤0.05
Total VFA	High^b	22.78 ± 0.85	28.38 ± 0.52	2.16	≤0.05
Molar proportion (%)
Acetate	Low^a	66.46 ± 0.50	64.03 ± 0.20	0.99	≤0.05
Acetate	High^b	65.55 ± 1.92	61.80 ± 1.18	2.25	≤0.05
Propionate	Low^a	25.39 ± 0.49	28.65 ± 0.26	1.25	≤0.05
Propionate	High^b	26.46 ± 2.02	31.41 ± 1.22	2.60	≤0.05
Butyrate	Low^a	8.15 ± 0.27	7.32 ± 0.14	0.39	≤0.05
Butyrate	High^b	8.00 ± 0.38	6.79 ± 0.10	0.56	≤0.05

^aThree vessels with one nylon bag containing PFAA hay and a second filled with PFAA-free hay
^bThree vessels with two nylon bags with PFAA hay
^cSix vessels contained two nylon bags filled with PFAA-free hay
^dComparison of the mean was performed using t test