Colour change of greenlip abalone, Haliotis Laevigata Donovan, fed dried macroalgae meals in concurrent laboratory and on-farm trials

Figures & data

Table 1. Proximate composition of mixed species macroalgae (MSM) meal and Gracilaria cliftonii meal and diets used in experimental treatments.

	Ingredient (meals)		Diets
Proximate composition (%)	MSM meal	G. cliftonii meal	Commercial diet	15% G. cliftonii meal + 85% commercial diet	15% MSM meal + 85% commercial diet
Carbohydrate^a	53	39	48.1	46.54	45.95
Lipid	0.40	1.10	4.20	4.10	3.90
Protein	9.40	25.20	29.70	29.56	30.75
Moisture	14.70	3.80	12.20	10.70	9.60
Ash	22.50	30.90	5.80	9.10	9.80
Energy (MJ kg^−1)	10.76	13.09	15.10	14.45	14.48
Diet stability (%)^b	-	-	65.75	53.91	73.84

^a Calculated by difference, carbohydrate % = 100% – (lipid % + protein % + moisture % + ash %).

^b Diet stability was calculated by immersing diets in water at 22 °C in culture tanks for 16 h, sieved through a fine mesh screen (500 µm), and dried till constant weight.

Table 2. Experiment 1 growth performance and feed utilisation for greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% Gracilaria cliftonii meal or a diet formulated to contain 85% of the commercial diet and 15% mixed species macroalgae (MSM) meal. The three-month laboratory feed trial was carried out to validate experiment 1 on farm feed trial.

Treatment	Commercial diet	15% G. cliftonii meal diet	15% MSM meal diet	ANOVA (P =)
Growth performance
Initial weight (g)	55.39 ± 1.02	55.76 ± 1.00	55.53 ± 0.59	0.958
Initial shell length (mm)	76.37 ± 0.25	76.37 ± 0.41	76.48 ± 0.48	0.976
Final weight (g)	72.08 ± 2.17	77.77 ± 0.81	72.12 ± 1.09	0.055
Final shell length (mm)	80.04 ± 0.92	82.00 ± 0.32	80.37 ± 0.25	0.110
Biomass gain (g tank^−1)	158.94 ± 22.86	226.07 ± 24.27	161.05 ± 13.41	0.104
SGR (% day^−1)	0.29 ± 0.01	0.36 ± 0.03	0.280 ± 0.02	0.064
Shell growth rate (µm day^−1)	39.85 ± 7.47^a	61.20 ± 1.74^b	42.31 ± 3.00^a	0.037
Feed utilisation
Feed intake	2.89 ± 0.35	3.08 ± 0.07	3.17 ± 0.05	0.645
(g as fed kg abalone^−1 day^−1)
Apparent FCR	1.27 ± 0.25	1.00 ± 0.11	1.33 ± 0.12	0.414

Notes: SGR = Specific growth rate. FCR = Feed conversion ratio. Means ± SE, n = 3. Means in the same row which share the same superscript are not significantly different (one-factor ANOVA; SNK; P > 0.05).

Figure 1. Experiment 1 lip and foot colour of greenlip abalone in either the 15% Gracilaria cliftonii meal treatment (formulated to contain 15% G. cliftonii meal (GM) and 85% of commercial diet) or the commercial treatment or the 15% MSM treatment (formulated to contain 15% mixed species macroalgae meal (MSM) and 85% of commercial diet) during a three-month laboratory feed trial. Bar = 1 cm.

Table 3. Experiment 1 colour properties of lip, foot and shell of greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% mixed species macroalgae (MSM) meal or a diet formulated to contain 85% of the commercial diet and 15% Gracilaria cliftonii meal during a three-month laboratory feed trial.

Treatment	Commercial diet			15% G. cliftonii meal			15% MSM meal			ANOVA (P =)
Month	1	2	3	1	2	3	1	2	3	Month (A)	Treatment (B)	A × B
Colour properties of lip
Hue (degree)	35.9 ± 0.61	41.2 ± 0.49	38.9 ± 0.78	40.9 ± 0.39	46.8 ± 0.57	47.1 ± 0.58	37.7 ± 0.63	42.1 ± 0.89	40.8 ± 0.33	< 0.001 (1 < 2 < 3)	< 0.001 (C < M < G)	0.074
Saturation (%)	26.7 ± 2.97	35.3 ± 3.42	33.0 ± 3.91	37.1 ± 1.82	47.0 ± 4.08	56.1 ± 2.21	27.3 ± 2.59	34.5 ± 3.92	37.7 ± 3.07	0.001 (1 < 2 = 3)	< 0.001 (C = M < G)	0.333
Brightness (%)	56.7 ± 0.77	52.1 ± 0.89	53.3 ± 1.14	56.1 ± 0.49	48.6 ± 1.08	48.9 ± 1.07	56.3 ± 0.33	51.6 ± 1.21	50.5 ± 0.99	< 0.001 (1 > 2 = 3)	0.006 (C = M > G)	0.247
Colour properties of foot
Hue (degree)	15.5 ± 1.03	15.9 ± 0.67	16.7 ± 1.30	16.9 ± 0.71	14.9 ± 0.08	16.1 ± 1.00	15.1 ± 0.83	15.7 ± 0.85	17.4 ± 0.86	0.233	0.982	0.425
Saturation (%)	59.1 ± 4.15	67.6 ± 2.34	66.0 ± 2.33	61.9 ± 2.42	66.9 ± 4.73	70.9 ± 1.82	58.2 ± 5.45	66.9 ± 3.07^b	67.9 ± 2.47	0.014 (1 < 2 = 3)	0.648	0.928
Brightness (%)	52.5 ± 0.87	44.6 ± 0.34	48.5 ± 0.53	53.1 ± 1.14	42.9 ± 2.28	45.0 ± 1.14	52.4 ± 0.57	44.8 ± 0.34	45.6 ± 1.58	< 0.001 (1 > 2 < 3)	0.288	0.247
Colour properties of shell
Hue (degree)	144.5 ± 10.19	126.1 ± 5.43	80.6 ± 4.55	128.9 ± 3.08	82.7 ± 9.18	54.4 ± 6.76	149.4 ± 5.52	107.0 ± 2.80	90.5 ± 7.56	< 0.001 (1 > 2 > 3)	< 0.001 (C = M > G)	0.146
Saturation (%)	30.9 ± 3.07^bc	27.2 ± 1.34^c	54.4 ± 6.76^bc	31.2 ± 1.17^bc	55.7 ± 5.80^a	63.5 ± 2.79^a	32.5 ± 3.75^bc	38.3 ± 2.05^bc	44.1 ± 2.14^b	< 0.001	< 0.001	0.002
Brightness (%)	45.4 ± 0.78	41.8 ± 1.02	42.1 ± 0.45	45.4 ± 0.96	40.8 ± 1.81	40.4 ± 2.23	44.0 ± 0.78	39.2 ± 1.23	41.5 ± 1.62	0.002 (1 > 2 = 3)	0.375	0.824

Notes: Means ± SE, n = 3. A significance level of P < 0.05 was used for all statistical tests. Where significant effects were detected, post-hoc tests were used to determine differences between all treatment combinations (two-factor ANOVA; SNK; P < 0.05). 1, 2 and 3 – months, respectively; Comm – commercial treatment; MSM – 15% MSM meal treatment; G – 15% G. cliftonii meal treatment. In the case of interactions means in the same row which share the same superscript are not significantly different (P > 0.05).

Table 4. Growth performance and feed utilisation for greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of commercial diet and 15% Gracilaria cliftonii meal during the preconditioning phase (months one to three) of a six-month phase feeding trial. During this phase the switched treatment was identical to the 15% G. cliftonii meal.

Treatment	Constant commercial diet	Constant 15% G. cliftonii meal diet	15% G. cliftonii meal diet switched to commercial diet	ANOVA (P =)
Growth performance
Initial weight (g)	55.39 ± 1.02	55.76 ± 1.00	54.57 ± 1.73	0.809
Initial shell length (mm)	76.37 ± 0.25	76.37 ± 0.41	74.70 ± 0.68	0.076
Final weight (g)	72.08 ± 2.17	77.77 ± 0.81	72.08 ± 2.17	0.104
Final shell length (mm)	80.04 ± 0.92	82.00 ± 0.32	81.78 ± 0.52	0.136
Biomass gain (g tank^−1)	158.94 ± 22.86	226.07 ± 24.27	220.81 ± 23.63	0.162
SGR (% day^−1)	0.29 ± 0.01	0.36 ± 0.03	0.38 ± 0.04	0.130
Shell growth rate (µm day^−1)	39.85 ± 7.47^a	61.19 ± 1.74^b	77.01 ± 4.45^b	0.006
Feed utilisation
Feed intake	2.89 ± 0.35	3.08 ± 0.07	2.99 ± 0.04	0.824
(g as fed kg abalone^−1 day^−1)
Apparent FCR	1.27 ± 0.25	1.00 ± 0.11	0.98 ± 0.09	0.450

Notes: SGR = Specific growth rate. FCR = Feed conversion ratio. Means ± SE, n = 3. Means in the same row which share the same superscript are not significantly different (one-factor ANOVA; SNK; P > 0.05).

Figure 2. Experiment 2 lip colour for greenlip abalone in either the 15% Gracilaria cliftonii meal treatment (formulated to contain 15% G. cliftonii meal (GM) and 85% of commercial diet) or the commercial treatment or the diet switch treatment during a six-month phase feeding trial. During the first phase (months one to three) of the trial, the diet switch treatment was the 15% G. cliftonii meal diet, and switched to the commercial diet during the second phase (months four to six). Bar = 1 cm.

Table 5. Experiment 2 colour properties of lip, foot and shell of greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% Gracilaria cliftonii meal during the preconditioning phase (months one to three) of a six-month phase feeding trial. The switched treatment was identical to the 15% G. cliftonii meal during this phase.

Treatment	Constant commercial diet			15% G. cliftonii meal diet			15% G. cliftonii meal diet switched to commercial diet			ANOVA (P =)
Month	1	2	3	1	2	3	1	2	3	Month (A)	Treatment (B)	A × B
Colour properties of lip
Hue (degree)	35.9 ± 0.61^d	41.2 ± 0.4^c	38.9 ± 0.78^c	40.9 ± 0.39^c	46.8 ± 0.57^a	47.1 ± 0.58^a	39.3 ± 0.20^c	43.7 ± 0.49^b	46.5 ± 0.59^a	< 0.001	< 0.001	0.005
Saturation (%)	26.7 ± 2.97	35.3 ± 3.42	33.0 ± 3.91	37.1 ± 1.82	47.0 ± 4.08	56.1 ± 2.84	39.1 ± 2.90	46.1 ± 2.31	56.1 ± 2.84	< 0.001 (1 < 2 < 3)	< 0.001 (C < S = G)	0.189
Brightness (%)	56.7 ± 0.76	52.1 ± 0.89	53.3 ± 1.14	56.1 ± 0.49	48.6 ± 1.0	48.9 ± 1.07	55.4 ± 1.35	51.3 ± 1.59	49.9 ± 1.75	< 0.001 (1 > 2 = 3)	0.028 (S = C + G;C > G)	0.411
Colour properties of foot
Hue (degree)	15.5 ± 1.03	15.9 ± 0.68	16.7 ± 1.30	16.9 ± 0.71	14.9 ± 0.08	16.1 ± 1.00	16.6 ± 0.29	16.5 ± 0.44	18.6 ± 0.73	0.123	0.120	0.369
Saturation (%)	59.1 ± 4.15	67.6 ± 2.34	66.0 ± 2.33	61.9 ± 2.42	66.9 ± 4.73	70.9 ± 1.82	60.9 ± 1.29	64.4 ± 4.23	67.5 ± 2.16	0.020 (1 < 2 = 3)	0.576	0.862
Brightness (%)	52.5 ± 0.87	44.6 ± 0.34	48.5 ± 0.53	53.1 ± 1.14	42.9 ± 2.29	45.0 ± 1.14	52.3 ± 1.16	47.5 ± 1.84	48.9 ± 1.86	< 0.001 (1 > 2 < 3)	0.288	0.393
Colour properties of shell
Hue (degree)	144.5 ± 10.19	126.1 ± 5.43	80.6 ± 4.55	128.9 ± 3.08	82.7 ± 9.18	54.4 ± 6.76	135.4 ± 8.48	82.7 ± 19.15	59.5 ± 4.46	< 0.001 (1 > 2 > 3)	0.002 (C > S = G)	0.380
Saturation (%)	30.9 ± 3.07^c	27.2 ± 1.34^c	34.8 ± 4.14^c	31.2 ± 1.17^c	55.7 ± 5.80^ab	63.5 ± 2.80^ab	35.3 ± 3.09^c	51.5 ± 6.06^b	67.2 ± 3.46^a	< 0.001	< 0.001	0.004
Brightness (%)	45.4 ± 0.78	41.8 ± 1.02	42.1 ± 0.45	45.4 ± 0.96	40.8 ± 1.81	40.4 ± 2.23	44.2 ± 0.77	41.6 ± 1.58	40.8 ± 1.24	0.003 (1 > 2 = 3)	0.631	0.929

Notes: Means ± SE, n = 3. A significance level of P < 0.05 was used for all statistical tests. Where significant effects were detected, post-hoc tests were used to determine differences between all treatment combinations (two-factor ANOVA; SNK; P < 0.05). 1, 2 and 3 – months respectively; Comm – commercial treatment; S – diet switch treatment; GM – 15% G. cliftonii meal treatment. In the case of interactions means in the same row which share the same superscript are not significantly different (P > 0.05).

Table 6. Growth performance and feed utilisation for greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of commercial diet and 15% Gracilaria cliftonii meal during the second phase (months four to six) of a six-month phase feeding trial. During this phase the switched treatment was identical to the commercial diet.

Treatment	Constant commercial diet	Constant 15% G. cliftonii meal diet	15% G. cliftonii meal diet switched to commercial diet	ANOVA (P =)
Growth performance
Initial weight (g)	70.83 ± 2.17	77.31 ± 0.67	73.87 ± 4.56	0.360
Initial shell length (mm)	79.65 ± 0.94	81.73 ± 0.71	80.52 ± 1.13	0.357
Final weight (g)	83.81 ± 2.97	96.46 ± 2.54	86.98 ± 4.26	0.083
Final shell length (mm)	85.27 ± 0.63	87.49 ± 0.86	85.61 ± 1.05	0.227
Biomass gain (g tank^−1)	90.88 ± 7.17	133.99 ± 21.13	91.78 ± 4.26	0.097
SGR (% day^−1)	0.20 ± 0.01	0.27 ± 0.04	0.20 ± 0.02	0.194
Shell growth rate (µm day^−1)	67.65 ± 4.18	69.37 ± 2.35	61.30 ± 3.61	0.295
Feed utilisation
Feed intake	2.55 ± 0.05	2.35 ± 0.09	2.56 ± 0.07	0.143
(g as fed kg abalone^−1 day^−1)
Apparent FCR	1.37 ± 0.04	1.04 ± 0.18	1.41 ± 0.08	0.116

Notes: SGR = Specific growth rate. FCR = Feed conversion ratio. Means ± SE, n = 3. Means in the same row which share the same superscript are not significantly different (one-factor ANOVA; SNK; P > 0.05).

Table 7. Growth performance and feed utilisation for greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% Gracilaria cliftonii meal during a six month phase feeding trial. During the first phase (months one to three) of the trial, the diet switch treatment was in the 15% G. cliftonii meal diet and switched to the commercial diet during the second phase (months four to six).

Treatment	Constant commercial treatment	Constant 15% G. cliftonii meal treatment	15% G. cliftonii meal diet switched to commercial diet	ANOVA (P =)
Growth performance
Initial weight (g)	55.39 ± 1.02	55.76 ± 1.00	54.57 ± 1.73	0.809
Initial shell length (mm)	76.37 ± 0.25	76.37 ± 0.41	74.70 ± 0.68	0.076
Final weight (g)	83.81 ± 2.97	96.49 ± 2.54	86.98 ± 4.26	0.083
Final shell length (mm)	85.27 ± 0.63	87.49 ± 0.86	85.61 ± 1.05	0.227
Biomass gain (g tank^−1)	243.44 ± 27.84^a	360.06 ± 3.71^b	316.36 ± 28.35^ab	0.031
SGR (% day^−1)	0.24 ± 0.02^a	0.27 ± 0.05^b	0.31 ± 0.01^ab	0.049
Shell growth rate (µm day^−1)	50.81 ± 3.02^a	63.54 ± 2.59^b	62.33 ± 3.00^b	0.037
Feed utilisation
Feed intake	3.08 ± 0.26	2.98 ± 0.09	3.22 ± 0.06	0.611
(g as fed kg abalone^−1 day^−1)
Apparent FCR	1.32 ± 0.14	0.98 ± 0.02	1.10 ± 0.08	0.106

Notes: SGR = Specific growth rate. FCR = Feed conversion ratio. Means ± SE, n = 3. Means in the same row which share the same superscript are not significantly different (one-factor ANOVA; SNK; P > 0.05).

Table 8. Experiment 2 colour properties of lip, foot and shell of greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of commercial diet and 15% Gracilaria cliftonii meal during the diet switch phase (months four to six) of a six month phase feeding trial. During this phase the switched treatment was identical to the commercial diet treatment.

Treatment	Constant commercial treatment				15% G. cliftonii meal Treatment				15% G. cliftonii meal diet switched to commercial diet				ANOVA (P =)
Month	3	4	5	6	3	4	5	6	3	4	5	6	Month (A)	Treatment (B)	A × B
Colour properties of lip
Hue (degree)	38.9 ± 0.78	40.9 ± 0.77	40.1 ± 0.69	39.8 ± 0.54	47.1 ± 0.58	46.0 ± 0.86	46.5 ± 1.06	44.5 ± 0.50	46.5 ± 0.59	44.4 ± 0.12	45.3 ± 0.32	43.1 ± 0.14	0.020 (3 = 4 = 5 > 6)	< 0.001 (C < S < G)	0.057
Saturation (%)	33.0 ± 3.91^f	36.8 ± 4.20^ef	32.6 ± 3.76^f	42.4 ± 1.80^def	56.1 ± 2.84^abc	57.1 ± 2.91^abc	59.0 ± 2.06^abc	69.1 ± 4.02^a	56.1 ± 2.84^abc	59.9 ± 4.17^ab	46.1 ± 0.69^cde	48.8 ± 0.84^bcd	0.030	< 0.001	0.013
Brightness (%)	53.3 ± 1.14^ab	52.0 ± 0.67^b	53.1 ± 1.26^b	51.9 ± 0.26^b	48.9 ± 1.07^bc	49.1 ± 0.80^bc	48.9 ± 0.51^bc	45.5 ± 1.73^c	49.9 ± 1.75^bc	48.8 ± 2.25^bc	54.3 ± 1.00^ab	57.4 ± 0.61^a	0.165	< 0.001 (C = S > G)	0.001
Colour properties of foot
Hue (degree)	16.7 ± 1.30	15.7 ± 1.13	15.1 ± 0.85	16.0 ± 0.69	16.1 ± 1.00	16.8 ± 0.63	16.8 ± 0.67	17.8 ± 0.24	18.6 ± 0.73	19.7 ± 0.69	16.8 ± 0.75	18.6 ± 0.88	0.249	0.001 (C = G < S)	0.452
Saturation (%)	66.0 ± 2.33	67.0 ± 3.25	65.3 ± 2.88	69.1 ± 0.96	70.9 ± 1.82	68.9 ± 2.83	70.3 ± 2.01	69.1 ± 3.37	67.5 ± 2.16	67.0 ± 3.55	62.0 ± 2.05	71.7 ± 0.60	0.262	0.248	0.424
Brightness (%)	48.5 ± 0.53	45.3 ± 2.35	46.7 ± 0.34	45.1 ± 1.60	45.0 ± 1.14	46.2 ± 1.66	45.3 ± 1.43	47.3 ± 1.73	48.9 ± 1.86	48.3 ± 1.88	51.1 ± 1.68	47.1 ± 1.04	0.707	0.032 (C = G < S)	0.386
Colour properties of shell
Hue (degree)	80.6 ± 4.55	63.9 ± 6.89	54.8 ± 0.45	54.6 ± 3.84	54.4 ± 6.76	43.4 ± 2.27	44.9 ± 2.51	42.1 ± 0.41	59.5 ± 4.46	50.9 ± 2.46	56.5 ± 4.78	56.5 ± 5.73	0.002 (3 > 4 = 5 = 6)	< 0.001 (C > S > G)	0.138
Saturation (%)	34.8 ± 4.14^e	53.1 ± 6.48^d	61.3 ± 1.92^cd	61.4 ± 5.35^cd	63.5 ± 2.80^bcd	74.3 ± 2.38^abc	78.6 ± 3.80^ab	85.1 ± 2.57^a	67.2 ± 3.46^bcd	67.7 ± 3.68^bcd	59.6 ± 1.56^cd	62.7 ± 2.71^bcd	< 0.001	<0.001	0.002
Brightness (%)	42.1 ± 0.45	43.1 ± 0.75	44.5 ± 1.35	44.5 ± 0.97	40.4 ± 2.23	40.1 ± 2.45	39.9 ± 1.52	40.3 ± 0.29	40.8 ± 1.24	43.7 ± 1.38	45.7 ± 2.53	47.2 ± 1.07	0.119	0.001 (C = S > G)	0.485

Notes: Means ± SE, n = 3. A significance level of P < 0.05 was used for all statistical tests. Where significant effects were detected, post-hoc tests were used to determine differences between all treatment combinations (two-factor ANOVA; SNK; (P < 0.05)). 3, 4, 5 and 6 – months respectively; C – constant commercial treatment; S – Diet switch treatment; G – 15% Gracilaria cliftonii meal treatment. In the case of interactions means in the same row, which share the same superscript are not significantly different (P > 0.05).

Figure 3. Experiment 3 lip and foot colour of greenlip abalone in either the commercial treatment or the 15% MSM treatment (formulated to contain 15% mixed species macroalgae meal (MSM) and 85% of commercial diet) during a four-month on-farm feed trial. Bar = 1 cm.

Table 9. Experiment 3 growth performance for greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% mixed species macroalgae (MSM) meal in a four-month on-farm feed trial.

Treatment	Commercial diet	15% MSM meal	ANOVA (P-=)
Initial weight (g)	55.71 ± 3.81	55.81 ± 3.51	0.986
Initial shell length (mm)	73.84 ± 1.09	73.97 ± 1.84	0.952
Final weight (g)	70.14 ± 3.62	67.61 ± 8.86	0.800
Final shell length (mm)	81.48 ± 0.47	79.68 ± 2.57	0.516
Biomass gain (g tank^−1)	14.42 ± 2.36	11.80 ± 5.37	0.670
Specfic growth rate (% day^−1)	0.22 ± 0.04	0.16 ± 0.07	0.482
Shell growth rate (µm day^−1)	72.76 ± 7.39	54.34 ± 7.55	0.132

Notes: Means ± SE, n = 4. Means in the same row which share the same superscript are not significantly different (one-factor ANOVA; SNK; P > 0.05).

Table 10. Experiment 3 colour properties of lip, foot and shell of greenlip abalone fed either a commercial diet or a diet formulated to contain 85% of the commercial diet and 15% mixed species macroalgae (MSM) meal during a four-month on farm feed trial.

Treatment	Commercial diet				15% MSM meal				ANOVA (P =)
Month	1	2	3	4	1	2	3	4	Month (A)	Treatment (B)	A × B
Colour properties of lip
Hue (degree)	70.4 ± 9.28	68.6 ± 7.15	63.5 ± 5.47	60.6 ± 5.51	73.1 ± 8.94	81.7 ± 12.15	67.0 ± 6.20	59.2 ± 4.54	< 0.001 (1 = 2 > 3 = 4)	0.036 (M > C)	0.101
Saturation (%)	25.4 ± 5.05	25.8 ± 3.97	26.7 ± 3.53	34.9 ± 4.58	26.4 ± 4.59	20.4 ± 3.10	25.4 ± 3.35	33.8 ± 5.71	< 0.001 (1 = 2 = 3 < 4)	0.185	0.344
Brightness (%)	47.3 ± 2.61	47.6 ± 2.16	52.4 ± 2.61	46.8 ± 2.07	44.9 ± 2.28	49.5 ± 2.17	51.0 ± 2.70	47.1 ± 3.06	< 0.001 (1 = 4 = 2 < 3)	0.568	0.149
Colour properties of foot
Hue (degree)	22.2 ± 1.68	21.6 ± 0.56	24.0 ± 0.84	23.0 ± 0.43	21.7 ± 1.65	21.4 ± 0.40	24.7 ± 0.75	24.7 ± 0.22	< 0.001 (1 = 2 < 3 = 4)	0.273	0.213
Saturation (%)	61.1 ± 4.60	63.2 ± 2.18	65.4 ± 7.05	63.9 ± 1.96	61.4 ± 3.52	61.6 ± 1.28	55.7 ± 0.78	61.1 ± 1.47	0.889	0.108	0.372
Brightness (%)	54.0 ± 3.63	52.1 ± 1.33	59.0 ± 0.88	52.0 ± 0.98	52.3 ± 3.37	52.7 ± 1.87	59.5 ± 0.44	57.4 ± 3.61	0.004 (1 = 2 = 3 > 4)	0.379	0.234
Colour properties of shell
Hue (degree)	121.7 ± 4.48	123.7 ± 4.63	109.7 ± 4.81	115.3 ± 4.02	129.1 ± 6.36	127.7 ± 2.77	113.9 ± 2.38	110.8 ± 1.28	0.007 (1 = 2 > 3 = 4)	0.092	0.962
Saturation (%)	40.4 ± 1.22	42.5 ± 1.20	42.6 ± 1.37	37.7 ± 2.50	36.9 ± 1.71	39.2 ± 0.75	38.6 ± 0.97	43.2 ± 2.37	0.462	0.230	0.016
Brightness (%)	33.8 ± 1.76	31.7 ± 1.95	32.4 ± 0.24	26.4 ± 3.20	34.5 ± 1.17	34.9 ± 0.38	32.4 ± 0.70	28.3 ± 1.57	0.002 (1 = 2 = 3 > 4)	0.107	0.645

Notes: Means ± SE, n = 3. A significance level of P < 0.05 was used for all statistical tests. Where significant effects were detected, post-hoc tests were used to determine differences between all treatment combinations (two-factor ANOVA; SNK; P < 0.05). 1, 2, 3 and 4 – months, respectively; Comm – commercial treatment; MSM – 15% MSM meal treatment.