Concentration of elements in the hair of growing and adult dogs

Figures & data

Table 1. Proximate analysis and concentrations of elements of the kibbles administered to the dog during the study.

Item	Unit	K1	K2	K3	K4
Crude Protein	% as fed	30.2	31.7	23.6	26.6
Oil and fat	“	18.3	17.6	9.5	18.3
Crude Fibre	“	2.9	3.2	4.6	4.2
Ash	“	6.2	7.0	8.7	6.6
Metabolisable energy	kcal	4008	3930	3399	3943
Ag	μg/g	b.d.l.	b.d.l.	b.d.l.	b.d.l.
Al	“	198.6	247.7	16.8	35.6
Ba	“	5.1	6.5	4.9	3.5
Ca	“	5988.2	7723.3	10129.9	8460.2
Cd	“	b.d.l.	b.d.l.	b.d.l.	b.d.l.
Co	“	b.d.l.	b.d.l.	b.d.l.	b.d.l.
Cr	“	1.2	b.d.l.	b.d.l.	0.3
Cu	“	9.6	9.3	9.0	10.3
Fe	“	90.2	118.2	92.3	94.5
K	“	3996.6	4211.9	3571.8	4256.2
Li	“	0.2	0.3	0.3	0.4
Mg	“	628.0	503.6	786.2	687.2
Mn	“	60.5	45.1	35.2	42.8
Na	“	1679.5	2488.2	2217.0	2015.2
Ni	“	0.7	b.d.l.	b.d.l.	b.d.l.
P	“	5407.7	6599.2	10506.4	7231.5
Pb	“	b.d.l.	0.8	b.d.l.	b.d.l.
Sr	“	11.9	14.0	17.7	20.5
Zn	“	131.1	132.3	84.7	140.4

G1: Growing dogs of small size, fed K1 diet; G2: Growing dogs of medium size, fed K2 diet; G3: Adult dogs of medium size, fed K3 diet; G4: Adult dogs of small size, fed K4 diet; b.d.l.: below detection limit.

Figure 1. Average daily intake of kibbles during the study. A, B and C denote means significantly different for p < .01. G1: Growing dogs of small size, fed K1 diet; G2: Growing dogs of medium size, fed K2 diet; G3: Adult dogs of medium size, fed K3 diet; G4: Adult dogs of small size, fed K4 diet. For K1, K2, K3 and K4 diets, see Table 1.

Figure 2. Effect of the diets on the mean concentrations of Al, Cu, Mn and Zn in the hair of dogs and reported as natural logarithm. These elements significantly differed between groups of dogs (Table 3) and the data reported are the average concentrations of the hair sampled at the beginning of the study (D0) and after 60 days (D60). Within each diagram, a, b denote means which significantly differ for p < .05 and A, B denote means which significantly differed for p < .01. G1: Growing dogs of small size, fed K1 diet; G2: Growing dogs of medium size, fed K2 diet; G3: Adult dogs of medium size, fed K3 diet; G4: Adult dogs of small size, fed K4 diet. For K1, K2, K3 and K4 diets, see Table 1.

Table 2. Mean concentrations and number of samples below the detection limits of the elements in the hair sampled from dog fed commercial diets at the beginning of the study (D0) and after 60 days (D60).

Element	Unit	D0				D60				SEM
		G1	G2	G3	G4	G1	G2	G3	G4
Ag	μg/g	2.9	2.8	4.8	11.4	10.6	11.8	6.8	20.7	3.5
Al	μg/g	554.5	510.2	326.0	613.2	645.9	711.4	297.8	937.5	58.6
Ba	μg/g	2.2	3.2	2.1	2.3	2.0	3.5	1.2	3.2	0.2
Ca	μg/g	1306.3	1297.5	1430.6	1342.1	1582.9	1482.4	1252.5	1715.5	117.8
Cd	μg/g	0.0	0.0	0.1	0.0	0.0	0.0	0.0	0.0	0.0
Co	μg/g	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
Cr	μg/g	0.4	0.9	0.2	0.3	1.0	0.7	0.7	0.9	0.1
Cu	μg/g	11.3	10.0	8.7	9.6	11.8	10.6	8.9	10.2	0.2
Fe	μg/g	518.4	355.8	324.8	451.1	541.9	448.7	236.9	663.2	42.5
K	μg/g	179.3	200.0	115.3	243.0	537.0	338.6	383.2	479.1	29.2
Li	μg/g	0.2	0.1	0.2	0.2	0.7	0.7	0.4	1.0	0.1
Mg	μg/g	532.1	340.0	311.8	486.6	436.1	290.2	242.7	479.2	30.5
Mn	μg/g	9.9	12.4	6.4	8.0	12.5	10.2	5.6	9.7	0.7
Na	μg/g	293.0	375.8	302.3	414.8	1202.1	734.3	1530.2	1116.1	75.1
Ni	μg/g	0.1	0.0	0.3	0.2	0.9	0.8	0.0	1.1	0.1
P	μg/g	326.4	267.4	296.5	300.4	336.0	292.4	273.6	296.6	8.2
Pb	μg/g	0.2	0.1	0.1	0.1	0.1	0.0	0.0	0.0	0.0
Sr	μg/g	2.4	2.9	2.8	2.2	2.6	3.9	5.1	4.3	0.4
Zn	μg/g	229.5	234.8	181.4	217.7	245.1	235.7	194.1	217.0	3.8
Number of Samples lower than b.d.l.
Ag	No < b.d.l.	6	4	9	10	7	4	8	10
Cd	No < b.d.l.	8	5	7	11	9	5	11	10
Co	No < b.d.l.	9	6	11	12	9	6	11	12
Cr	No < b.d.l.	3	4	6	4	4	2	1	6
Ni	No < b.d.l.	7	6	7	10	4	2	11	4
Pb	No < b.d.l.	9	5	10	10	9	6	11	12

G1: Growing dogs of small size; G2: Growing dogs of medium size; G3: Adult dogs of medium size; G4: Adult dogs of small size; b.d.l.: below detection limit.

Table 3. Results of the statistical analysis and estimated mean concentrations of the elements in the hair sampled from dog fed commercial diets at the beginning of the study (D0) and after 60 days (D60). Since data were not normally distributed, a natural logarithmic transformation was applied.

									Main Effects and Interactions (p values)					Covariate
Element	Unit	G1	G2	G3	G4	D0	D60	SEM	Diet	Time	Sex	G × T	G × S
Al	μg/g	6.510	6.560	5.470	6.220	6.120	6.260	0.110	.009	NS	NS	NS	NS	0.731
Ba	μg/g	0.340	1.540	0.900	0.160	0.850	0.620	0.090	NS	NS	NS	NS	NS	0.141
Ca	μg/g	6.930	7.120	7.370	6.910	7.090	7.080	0.080	NS	NS	NS	NS	NS	0.439
Cu	μg/g	2.370	2.360	2.280	2.220	2.280	2.220	0.020	.009	.027	NS	NS	NS	0.056
Fe	μg/g	6.260	5.840	5.300	6.140	5.860	5.910	0.080	NS	NS	NS	NS	NS	0.803
K	μg/g	5.280	5.840	5.900	5.200	5.160	5.930	0.110	NS	.000	NS	NS	NS	0.001
Li	μg/g	−0.990	−1.380	−1.530	−1.010	−1.270	1.260	0.090	NS	.000	NS	.043	NS	0.831
Mg	μg/g	5.770	5.530	6.240	5.670	5.950	5.660	0.080	NS	.022	NS	NS	NS	0.076
Mn	μg/g	2.360	2.400	1.820	1.710	2.130	2.020	0.090	.022	NS	NS	NS	NS	0.371
Na	μg/g	6.230	6.120	6.440	6.230	5.680	6,860	0.120	NS	.000	NS	.022	NS	0.968
P	μg/g	5.780	5.610	5.670	5.660	5.680	5.670	0.030	NS	NS	NS	NS	NS	0.821
Sr	μg/g	0.460	0.990	1.280	0.730	0.760	0.970	0.090	NS	NS	NS	NS	NS	0.432
Zn	μg/g	5.370	5.560	5.320	5.300	5.370	5.400	0.020	.000	NS	NS	NS	NS	0.003

G1: Growing dogs of small size; G2: Growing dogs of medium size; G3: Adult dogs of medium size; G4: Adult dogs of small size; G × T = Interaction Group and Time of Sampling; G × S = Interaction Group and Sex.

Figure 3. Effect of the time of sampling on the concentration of K, and Li and Na in the hair of dogs at the beginning (D0) and after 60 days (D60) of the study. These elements significantly differed between time of sampling for the groups G1, G2 G3 and G4 (Table 3). G1: Growing dogs of small size, fed K1 diet; G2: Growing dogs of medium size, fed K2 diet; G3: Adult dogs of medium size, fed K3 diet; G4: Adult dogs of small size, fed K4 diet. For K1, K2, K3 and K4 diets, see Table 1.

Figure 4. Estimated means of cortisol concentrations in the hair samples regrowth after 60 days from the beginning of the study. G1: Growing dogs of small size, fed K1 diet; G2: Growing dogs of medium size, fed K2 diet; G3: Adult dogs of medium size, fed K3 diet; G4: Adult dogs of small size, fed K4 diet. For K1, K2, K3 and K4 diets, see Table 1.

Figure 5. Significant correlations (p < .01; n = 78) between the concentrations of Aluminium and Iron (Al vs Fe; r = 0.922), Aluminium and Magnesium (Al vs Mg; r = 0.715) and Magnesium and Iron (Fe vs Mg; r = 0.978) in the hair of the 4 groups of dogs fed different diets. Correlations were calculated for the hairs sampled at the beginning of the study and after 60 days of regrowth (n = 78).