Casein
(n=6) / Hydrolysed casein
(n=5) / Free amino acid
(n=5)
Centrifugation Fraction / Bacterial
DNA / Human
DNA 3 / Total
DNA / Bacterial
DNA / Human
DNA3 / Total
DNA / Bacterial
DNA / Human DNA3 / Total
DNA / P
250×g precipitate / 0.06
(± 0.005) / 0.20
(± 0.01) / 0.26
(± 0.04) / 0.06
(± 0.005) / 0.24
(± 0.03) / 0.30
(± 0.03) / 0.06
(± 0.005) / 0.23
(± 0.025) / 0.29
(± 0.04) / NS
14500×g Precipitate 1 / 0.45
(± 0.05) / 0.45
(± 0.05) / 0.50
(± 0.05) / 0.50
(± 0.05) / 0.36
(± 0.04) / 0.36
(± 0.04) / NS
14500×g Supernatant 2 / 0.58
(± 0.05) / 0.06
(± 0.005) / 0.64a
(± 0.05) / 0.72
(± 0.06) / 0.04
(± 0.004) / 0.76b
(± 0.07) / 0.45
(± 0.05) / 0.05
(± 0.004) / 0.50c
(± 0.05) / < 0.01
Total / 1.09
(± 0.14) / 0.26
(± 0.03) / 1.35
(± 0.16) / 1.28
(± 0.15) / 0.28
(± 0.04) / 1.56
(± 0.13) / 0.87
(± 0.07) / 0.28
(± 0.04) / 1.15
(± 0.19) / NS
Table 4 Mean concentrations of DNA in the terminal ileal digesta for each dietary group
Values are means [mg/g NDDM](± SEM) The probability values refer to Total DNA data
1.It was assumed that all of the DNA detected in the 14500 precipitate was bacterial in origin. A DNA/DAPA ratio was calculated based on this precipitate and used to estimate the bacterial DNA in the other two centrifugation fractions.
2. Bacterial DNA in this fraction was assumed to originate from lysed bacterial cells and was determined from the DNA/DAPA ratio.
3.Human DNA was determined as being the difference between the total DNA detected and the estimated bacterial DNA.
Abbreviations: DAPA, Diaminopimelic acid, DNA, deoxyribonucleic acid, NDDM, native digesta dry matter,NS, not significant (P > 0.05).