TABLE 3.

Determination of turnover rates for acetate in hindmost gut sections IV and V of the three fish species

Species	Gut section	Expta	Temp (°C)	Turnover constantb (min−1)	Mean pool sizec (μmol ml−1)	Acetate turnoverd (nmol ml−1 min−1)
K. sydneyanus	IV	1	19	0.0051	55.2 ± 7.6	281
		2	22.5	0.015	29.2 ± 4.1	438
		3	16	0.02	32.2 ± 4.6	655
		4	18.5	0.019	38.9 ± 8.6	747
		5	18.5	0.027	26.9 ± 7.6	724
	V	1	19	0.0145	42.7 ± 3.9	619
		2	22.5	0.0063	44.3 ± 7.4	274
		3	16	0.0162	27.6 ± 1.5	450
		4	18.5	0.0107	42.0 ± 4.2	452
O. pullus	IV	1	20	0.04	18.6 ± 3.8	749
		2	20	0.036	14.5 ± 3.4	525
		3	16	0.028	13.3 ± 2.3	381
	V	1	20	0.021	5.9 ± 1.1	130
		2	20	0.046	10.8 ± 2.5	497
		3	18	0.025	19.7 ± 8.5	492
A. arctidens	IV	1	19	0.0256	10.1 ± 4.2	259
		2	16	0.0246	14.9 ± 7.6	365
	V	1	22	0.0064	18.1 ± 4.9	116
		2	19	0.0069	20.3 ± 4.9	140
		3	16	0.0126	10.6 ± 4.8	134

^aIn each experiment samples were removed from the gut section in duplicate at various intervals over 120 min (n = 5 and 4 for sections IV and V of K. sydneyanus and 3 for the same gut sections in O. pullus and A. arctidens, respectively).

^bDetermined as the slope of plots of log specific activity [2-¹⁴C]acetate versus time (see Fig. 2) × 2.303.

^cMeans are for samples taken in duplicate over the time course of the experiment (120 min) ± one standard deviation.

^dDetermined as the pool size versus turnover rate constant.