Table 3.

Fluid nutrient concentrations and digesta content masses in different regions of the gut of four species of herbivorous (Campostoma) and carnivorous (Nocomis) minnows

Gut region	C. anomalum	C. oligolepis	C. pauciradii	N. micropogon
Glucose (mM)
Proximal	4.19 ± 0.40	5.49 ± 0.94b	6.07 ± 0.49	3.41 ± 1.58
Mid	3.97 ± 0.51	2.54 ± 0.39ab	3.22 ± 0.36	–
Distal	5.69 ± 1.17	2.50 ± 0.42a	3.22 ± 1.88	3.74 ± 1.82
	F2,17 = 1.47	F2,29 = 4.05	F2,14 = 2.43	t = 0.14
	P = 0.26	P = 0.03	P = 0.13	P = 0.89
Protein (mg/ml)
Proximal	14.69 ± 2.90	30.41 ± 4.86b	26.26 ± 4.81b	17.60 ± 5.39
Mid	11.12 ± 1.31	11.73 ± 1.93a	13.53 ± 4.14ab	–
Distal	11.37 ± 1.28	12.04 ± 2.21a	9.51 ± 3.66a	18.86 ± 5.32
	F2,17 = 1.01	F2,29 = 10.66	F2,14 = 4.27	t = 0.17
	P = 0.39	P < 0.01	P = 0.04	P = 0.87
Lipid (mg/ml)
Proximal	14.84 ± 5.00	40.72 ± 5.09b	18.43 ± 6.04b	12.71 ± 2.04
Mid	12.78 ± 2.81	10.96 ± 1.19a	10.71 ± 2.54b	–
Distal	5.21 ± 0.34	12.40 ± 3.86a	3.40 ± 2.08a	8.81 ± 2.53
	F2,17 = 0.35	F2,29 = 25.63	F2,14 = 5.69	t = 1.20
	P = 0.71	P < 0.01	P = 0.02	P = 0.27
Gut content mass (GCM/BM)
Proximal	0.013 ± 0.002	0.032 ± 0.004	0.019 ± 0.003	0.012 ± 0.002
Mid	0.015 ± 0.006	0.027 ± 0.002	0.022 ± 0.004	–
Distal	0.006 ± 0.001	0.029 ± 0.003	0.024 ± 0.007	0.013 ± 0.003
	F2,26 = 1.22	F2,29 = 0.86	F2,29 = 0.29	t = 0.37
	P = 0.31	P = 0.43	P = 0.75	P = 0.72

Values are mean ± SEM. Comparisons were made among gut regions for each nutrient class and gut content mass for the Campostoma species with ANOVA followed by Tukey’s HSD with a family error rate of P = 0.05. Nutrient concentrations or gut masses for a particular species that share a superscript letter are not significantly different. Comparisons were made among the two gut regions in N. micropogon with t-test. Sample sizes (nutrient analyses; gut content mass): C. anomalum (6; 9), C. oligolepis (10; 10), C. pauciradii (5; 10), and N. micropogon (5; 5)