Comparative biochemical composition of wild and farm origin grayling (Thymallus thymallus) eggs

Figures & data

Figure 1. Principal component analysis (PCA). (A) PCA of wild (N = 5) and farm origin grayling eggs (N = 11) based on fatty acid (FA) content (% of total), FA ratios and protein content (see Table 1). (B) Projections of loading densities for the first two principal components of FA content (% of total), FA ratios and protein content (same as in Table 1), affecting distribution of egg samples in (a).

Table 1. Sum of fatty acid (FA) and protein content in mg/100 g of grayling egg wet weight, fatty acid profile in wild and farm origin grayling eggs in mg/100 g of fresh matter and in % of individual FA of total identified. Composition of FA groups and ratios in wild and farm origin grayling eggs are also presented. Statistical significance of difference between the means of the two groups is indicated with P value.

	Wild origin eggs	Farm origin eggs	Significance	Wild origin eggs	Farm origin eggs	Significance
	g/100 g of fresh material
FA sum	6.18 ± 0.36	6.67 ± 1.41
Proteins	22.48 ± 0.93	19.47 ± 2.11	p < 0.01
Fatty acid	mg/100g of fresh matter			% of total FAs
C14:0	104.5 ± 11.37	105.14 ± 15.12		1.72 ± 0.12	1.54 ± 0.08	p < 0.001
C14:1 n-5	1.67 ± 0.27	0.56 ± 0.08	p < 0.01	0.03 ± 0.01	0.01 ± 0.00	p < 0.001
C16:0	991.25 ± 67.84	874.29 ± 124.25		16.36 ± 0.26	12.91 ± 0.31	p < 0.001
sum C16:1*	311.61 ± 39.60	185.27 ± 25.28	p < 0.001	5.14 ± 0.54	2.72 ± 0.09	p < 0.001
C18:0	201.43 ± 17.07	146.13 ± 21.90	p < 0.001	3.33 ± 0.26	2.18 ± 0.12	p < 0.001
sum C18:1*	1487.98 ± 109.94	1894.80 ± 224.31	p < 0.01	24.55 ± 0.76	27.75 ± 0.90	p < 0.001
C18:2 n-6	597.19 ± 55.67	824.65 ± 98.78	p < 0.001	9.89 ± 1.20	12.05 ± 0.70	p < 0.001
C18:3 n-6	27.47 ± 6.97	23.13 ± 4.81		0.46 ± 0.12	0.35 ± 0.08	p < 0.05
C18:3 n-3	177.71 ± 39.22	245.90 ± 34.88	p < 0.01	2.92 ± 0.54	3.58 ± 0.17
C18:4 n-3	53.58 ± 7.54	73.65 ± 10.69	p < 0.01	0.88 ± 0.11	1.09 ± 0.14	p < 0.01
C20:0	1.99 ± 1.83	6.16 ± 1.09	p < 0.01	0.03 ± 0.03	0.09 ± 0.01	p < 0.05
C20:1 n-9	40.09 ± 3.77	98.72 ± 16.39	p < 0.001	0.67 ± 0.10	1.46 ± 0.12	p < 0.001
C20:2 n-6	67.80 ± 4.97	57.22 ± 9.24	p < 0.05	1.12 ± 0.11	0.84 ± 0.06	p < 0.001
C20:3 n-6	37.96 ± 10.76	25.02 ± 3.77		0.63 ± 0.21	0.38 ± 0.05
C20:4 n-6 (ARA)	176.48 ± 5.02	55.33 ± 8.78	p < 0.001	2.92 ± 0.18	0.83 ± 0.04	p < 0.001
C20:3 n-3	18.95 ± 4.45	15.67 ± 2.71		0.31 ± 0.06	0.23 ± 0.02	p < 0.01
C20:4 n-3	22.16 ± 3.24	40.07 ± 6.46	p < 0.001	0.37 ± 0.04	0.58 ± 0.05	p < 0.001
C20:5 n-3 (EPA)	486.47 ± 62.08	307.60 ± 47.44	p < 0.001	8.01 ± 0.70	4.56 ± 0.18	p < 0.001
C22:1 n-9c	0.00 ± 0.00	6.57 ± 1.34	p < 0.001	0.00 ± 0.00	0.10 ± 0.01	p < 0.001
C22:2 n-6	3.23 ± 0.88	4.54 ± 1.16	p < 0.05	0.05 ± 0.01	0.06 ± 0.01
C22:4 n-6	10.51 ± 0.72	2.34 ± 0.61	p < 0.001	0.17 ± 0.02	0.03 ± 0.01	p < 0.001
C22:5 n-6 (n-6 DPA)	49.61 ± 3.60	22.89 ± 3.19	p < 0.001	0.82 ± 0.07	0.34 ± 0.02	p < 0.001
C22:5 n-3 (n-3 DPA)	161.69 ± 23.38	79.44 ± 12.02	p < 0.01	2.66 ± 0.26	1.17 ± 0.07	p < 0.001
C22:6 n-3 (DHA)	918.85 ± 56.58	1629.81 ± 250.99	p < 0.001	15.18 ± 0.61	24.22 ± 1.24	p < 0.001
SFA	1372.80 ± 90.40	1166.48 ± 164.56	p < 0.05	22.66 ± 0.37	17.22 ± 0.37	p < 0.001
MUFA	1854.96 ± 135.06	2207.21 ± 262.75	p < 0.05	30.61 ± 1.00	32.35 ± 0.84	p < 0.001
PUFA	2819.21 ± 150.01	3412.07 ± 451.29	p < 0.05	46.56 ± 1.18	50.39 ± 0.71	p < 0.001
n-6 PUFA	942.78 ± 69.12	991.99 ± 117.53		15.62 ± 1.66	14.53 ± 0.67
n-3 PUFA	1839.41 ± 160.77	2392.15 ± 350.39	p < 0.01	30.33 ± 1.24	35.44 ± 1.26	p < 0.001
LC PUFA	1788.80 ± 101.97	2155.95 ± 326.76	p < 0.05	29.54 ± 0.73	32.01 ± 1.46	p < 0.01
LC n-6 PUFA	345.60 ± 14.77	167.34 ± 23.09	p < 0.001	5.73 ± 0.51	2.48 ± 0.08	p < 0.001
LC n-3 PUFA	1608.12 ± 135.56	2072.59 ± 316.22	p < 0.01	26.52 ± 1.12	30.77 ± 1.44	p < 0.001

*sum of positional and geometric isomers of FA.

ARA: Arachidonic acid, EPA: Eicosapentaenoic acid, DPA: Docosapentaenoic acid, DHA: Docosahexaenoic acid, SFA: Saturated fatty acids, MUFA: Monounsaturated fatty acids, PUFA: Polyunsaturated fatty acids.

Figure 2. Sum of fatty acids (FA) and protein content in the wild and farm origin grayling eggs. Statistically significant difference between the means of two groups is denoted by asterisks (** - p < 0.01).

Figure 3. Proportion (% of total) of the EFA and FA groups (DHA, EPA, ARA, SFA, MUFA, PUFA) in the wild and farm origin grayling eggs. Statistically significant difference between the means of two groups is denoted by asterisks (*** - p < 0.001). DHA: Docosahexaenoic acid, EPA: Eicosapentaenoic acid, ARA: Arachidonic acid, SFA: Saturated fatty acids, MUFA: Monounsaturated fatty acids, PUFA: Polyunsaturated fatty acids.

Figure 4. Fatty acid ratios in wild and farm origin grayling eggs. Statistically significant difference between the means of two groups is denoted by asterisks (*** - p < 0.001). EPA: Eicosapentaenoic acid, ARA: Arachidonic acid, DHA: Docosahexaenoic acid, PUFA: Polyunsaturated fatty acids.

Figure 5. Embryo and larval development. (A) Normal developing wild origin grayling larvae before hatching (A, B, C) and after hatching (C, D). Wild origin eggs are intensively yellow/orange coloured. (B) Deformities noticed in farm origin grayling larvae before hatching (A, B, C) and after hatching (D, E, F). Spine malformations, such as coiled tail (A, B, C) or bended spine (D, E) and jaw malformations (E, F) are shown. Farm origin eggs are pale, light yellow coloured.

Table 2. Colorimetric values L*, a* and b* measured for wild and farm origin grayling eggs. Average ± SD of all three parameters, and significance of comparison between both groups of eggs is presented.

	Wild origin eggs	Farm origin eggs	Significance
L* (lightness)	50 ± 4.9	62.4 ± 4.3	p < 0.001
a* (redness)	14.7 ± 5.1	−0.8 ± 1.2	p < 0.01
b* (yellowness)	42.7 ± 6.5	22.7 ± 8.4	p < 0.001

Data availability statement

The data presented in this study are available on request from the corresponding author upon reasonable request.