Potential androgenic effects of urban sewage sludge in male rats

Figures & data

Table 1. Body weight gain, mean water/food consumption and SS intake of immature animals¹ in different groups at the end of the experiment

Groups (ppm)	Number of animals	Body weight gain^2	Water consumption (ml/rat/day)	Food consumption (g/rat/day)	SS consumption (g/kg bw per day)
Negative Control	10	59.4 ± 7.78	17.13 ± 4.87	10.43 ± 3.38	—
TP (androgenic control)	10	71.7 ± 2.95	19.63 ± 5.69	11.41 ± 3.34	—
TP+FLU (anti-androgenic control)	10	66.1 ± 3.35	19.90 ± 5.54	10.56 ± 3.14	—
TP+SS 10000 ppm	10	69.7 ± 5.17	16.75 ± 3.77	10.17 ± 3.26	0.91 ± 0.02
TP+SS 20000 ppm	10	69.2 ± 9.41	17.83 ± 4.25	10.83 ± 3.40	1.85 ± 0.04

¹ Values are mean ± SD.

² Body weight gain = final minus initial body weight.

Note: Animals were 21-day old at the start of treatment. They were dosed on 10 consecutive days with an oral dose of test compound at the appropriate concentration levels and were stimulated by an sc injection of 1mg/kg/day TP; ¹ Values are mean ± SD, and were compared to the final body weight in g for the liver, and in mg for the other organs; Comparisons were performed first between the Negative control and TP-only groups for statistical significance (^a P < 0.05) to ensure that the TP induced the appropriate androgenic effects. A second comparison was performed between TP and TP plus sewage sludge (SS) or FLU (^b P < 0.05); TP: testosterone propionate; FLU: flutamide.

Table 2. Relative organs weights (%) of immature animals in different groups at the end of the experiment

			Relative weights (%)
Groups	Number of animals	Final body weights (g)	Liver	Kidneys	Adrenals	Testes	Epididymes	Ventral prostate	Full seminal vesicle
Negative Control	10	104.8 ± 12.74	5.06 ± 0.28	500.69 ± 43.12	23.2 ± 27.3	364.32 ± 16.82	40.19 ± 3.24	35.56 ± 4.11	14.77 ± 2.73
TP (androgenic control)	10	120.1 ± 7.11	5.28 ± 0.15	496.01 ± 37.34	10.8 ± 1.27	166.97 ± 14.82	52.31 ± 5.16	68.45 ± 9.64	104.32 ± 36.67
TP+FLU (anti-androgenic control)	10	109.3 ± 10.05	5.28 ± 0.29	514.47 ± 42.21	26.8 ± 33.6	126.64 ± 36.19	30.18 ± 4.04	43.79 ± 4.43	56.05 ± 25.75
TP+SS 10000 ppm	10	111.3 ± 8.14	5.22 ± 0.30	503.82 ± 26.49	12.2 ± 3.45	154.65 ± 17.65	52.52 ± 7.28	75.22 ± 13.79	115.84 ± 25.67
TP+SS 20000 ppm	10	117.3 ± 11.84	5.18 ± 0.56	525.25 ± 59.77	11.6 ± 1.89	187.12 ± 32.25	54.37 ± 8.17	64.99 ± 16.87	93.04 ± 36.35

Note: Animals were 21-day old at the start of treatment. They were dosed on 10 consecutive days with an oral dose of test compound at the appropriate concentration levels and were stimulated by an sc injection of 1mg/kg/day TP; ¹ Values are mean ± SD, and were compared to the final body weight in g for the liver, and in mg for the other organs; Comparisons were performed first between the Negative control and TP-only groups for statistical significance (^aP < 0.05) to ensure that the TP induced the appropriate androgenic effects. A second comparison was performed between TP and TP plus sewage sludge (SS) or FLU (^bP < 0.05); TP: testosterone propionate; FLU: flutamide.

Table 3. Body weight gain, mean water/food consumption and SS intake of pubertal animals¹ (98-day old) in different groups at the end of the experiment

Groups (ppm)^2	Number of animals	Body weight gain^3	Water consumption (ml/rat/day)	Food consumption (g/rat/day)	SS consumption (g/kg bw per day)
Negative control	10	247.6 ± 27.3	37.09 ± 2.61	23.36 ± 2.16	—
SS (2500)	10	239.4 ± 17.5	38.96 ± 4.88	25.59 ± 2.68^*	0.20 ± 0.004
SS (5000)	10	247.3 ± 19.4	37.29 ± 2.82	25.99 ± 3.88^*	0.40 ± 0.004
SS (10000)	10	257.1 ± 26.2	38.64 ± 2.99^*	27.08 ± 1.48^*	0.84 ± 0.003
SS (20000)	10	232.6 ± 14.9	40.81 ± 2.84^*	26.95 ± 1.93^*	1.67 ± 0.02

¹ Values are mean ±SD.

² Sewage Sludge (SS) in the diet.

³ Body weight gain = final minus initial body weight.

* Means differ from Negative control at P < 0.05.

Table 4. Relative organs weights (%)¹ of pubertal animals (98-day old) in different groups at the end of the experiment

Groups^2 (ppm)	Number of animals	Final body weights(g)	Liver	Kidneys	Adrenals	Testes	Epididymes	Ventral prostate	Full seminal vesicle
Negative control	10	409 ± 30.9	3.48 ± 0.23	0.29 ± 0.02	0.01 ± 0.001	0.36 ± 0.02	0.11 ± 0.01	0.08 ± 0.01	0.26 ± 0.04
SS (2500)	10	421.2 ± 21.2	3.63 ± 0.17	0.29 ± 0.02	0.01 ± 0.001	0.37 ± 0.03	0.11 ± 0.01	0.09 ± 0.01	0.23 ± 0.04
SS (5000)	10	433.3 ± 23.7	3.47 ± 0.42	0.30 ± 0.01	0.01 ± 0.001	0.36 ± 0.03	0.10 ± 0.01^*	0.07 ± 0.03	0.23 ± 0.07
SS (10000)	10	426.6 ± 34.3	3.75 ± 0.30	0.29 ± 0.02	0.01 ± 0.001	0.35 ± 0.02	0.10 ± 0.01^*	0.08 ± 0.01	0.24 ± 0.04
SS (20000)	10	413.1 ± 31.1	3.49 ± 0.29	0.31 ± 0.02^*	0.01 ± 0.001	0.37 ± 0.02	0.11 ± 0.01	0.07 ± 0.01	0.22 ± 0.02

¹ Values are mean ± SD, and were compared to the final body weight in g for the liver, and in mg for the other organs.

* Means differ from Negative control at P < 0.05.

² Sewage Sludge (SS) in the diet.

Table 5. Plasma hormones levels¹ of pubertal animals (98-day old) in different groups at the end of the experiment

Groups^2 (ppm)	Number of animals	FSH (ng/ml)	LH (ng/ml)	DHT (pg/ml)	T (ng/ml)
Negative control	10	13.63 ± 2.21	19.84 ± 16.16	136.05 ± 57.99	1.49 ± 1.08
SS (2500)	10	10.31 ± 2.16^*	6.56 ± 2.35^*	145.15 ± 80.84	2.45 ± 2.11
SS (5000)	10	9.58 ± 0.97^*	8.12 ± 1.81	140.38 ± 90.16	1.68 ± 1.34
SS (10000)	10	9.99 ± 1.38^*	12.82 ± 10.86	96.91 ± 42.52	0.88 ± 0.48
SS (20000)	10	9.46 ± 1.24^*	11.44 ± 6.04	146.30 ± 101.32	2.85 ± 2.76

¹ Values are mean ±SD.

² Sewage Sludge (SS) in the diet. FSH: Follicle-Stimulating Hormone; LH: Luteinizing Hormone; DHT: dihydrotestosterone; T: Testosterone.

* Means differ from Negative control at P < 0.05.

Table 6. Sperm counts¹ of pubertal animals (98-day old) in different groups at the end of the experiment

Groups (ppm)	Number of animals	Sperm number in testis (x106)	Daily sperm production (x106/testis/day)	Relative sperm production (x106/g testis/day)	Sperm number in the caput/corpus epididymis (x106)	Sperm transit time in the caput/corpus epididymis (days)	Sperm number in the cauda (x106)	Sperm transit time in the cauda (days)
Negative control	10	176.57 ± 18.99	28.95 ± 3.11	21.71 ± 2.63	101.92 ± 13.63	3.54 ± 0.51	156.53 ± 18.86	5.43 ± 0.59
SS (2500)	10	180.46 ± 18.07	29.58 ± 2.96	20.73 ± 1.26	111.53 ± 12.41	3.79 ± 0.45	154.35 ± 17.54	5.28 ± 0.86
SS (5000)	10	191.49 ± 21.40	31.39 ± 3.51	22.14 ± 1.91	98.05 ± 14.91	3.15 ± 0.53	139.98 ± 16.91	4.48 ± 0.42
SS (10000)	10	178.87 ± 21.01	29.32 ± 3.44	21.72 ± 1.71	100.92 ± 18.98	3.48 ± 0.76	140.27 ± 15.21	4.85 ± 0.81
SS (20000)	10	180.99 ± 29.07	29.67 ± 4.77	20.79 ± 2.05	101.15 ± 12.92	3.47 ± 0.56	146.07 ± 23.18	5.03 ± 1.09

¹ Values are mean ± SD.

Table 7. Sperm motility¹ of pubertal animals (98-day old) in different groups at the end of the experiment

Groups (ppm)	Number of animals	Type A sperm (%)	Type B sperm (%)	Type C sperm (%)
Negative Control	10	63.3 ± 12.4	23.7 ± 9.5	13.9 ± 2.9
SS (2500)	10	48.1 ± 12.1	28.7 ± 11.6	23.7 ± 5.3
SS (5000)	8	61.7 ± 9.1	22.4 ± 8.1	16.4 ± 4.7
SS (10000)	10	30.9 ± 11.1	41.5 ± 13.2	27.9 ± 8.9
SS (20000)	9	26.9 ± 9.3	40.4 ± 7.5	33.0 ± 9.6

¹ Values are mean ±SD. Means differ from negative control at *P < 0.05; Type A sperm:mobile with progressive trajectory; Type B sperm: mobile with non-progressive trajectory; Type C sperm: immotile.

Figure 1. Experimental design of the study.