Effect of krill meal on the reproductive performance of broodstock Nile tilapia, Oreochromis niloticus

Figures & data

Table 1. Ingredient and proximate composition of feeds used in the present study.

	Composition (% of the diet, as-is)
Ingredient	Control	2% KM	5% KM
Soybean meal	–	35.19	35.00
Corn DDGS	–	22.51	22.73
Wheat bran	–	15.67	15.88
Corn gluten meal	–	10.00	7.57
Corn	–	5.00	5.00
Hydrolyzed poultry and feather meal	–	5.00	5.00
Dicalcium phosphate	–	2.19	2.03
Soy lecithin, oil	–	1.31	0.87
Krill meal, full-fat	–	2.00	5.00
Calcium propionate, 99%	–	0.50	0.50
Soybean oil	–	0.19	–
Vitamin-mineral premix	–	0.25	0.25
Rovimix® Stay C® 35	–	0.10	0.10
DL-Methionine, 99%	–	0.08	0.07
Proximate composition (% of the diet, as-is)
Dry matter	91.25	92.03	90.09
Crude protein	37.82	38.86	37.35
Crude fat	4.83	4.22	5.68
Total fiber	2.99	4.53	4.37
Ash	6.02	6.28	6.08

Figure 1. Mean number of eggs (x 1,000 ± standard error) per hapa and total number of tilapia larvae (x 1,000, ± se) per hapa (at day 10 post collection) produced over a 12-week period. Fish were fed a commercial diet (control), and diets containing 2 and 5% krill meal (KM). Each hapa was stocked with 50 female tilapia.

Figure 2. Mean number of spawning females (± standard error, se) per hapa and total number of spawns per hapa (x 1,000 ± se) from Nile tilapia broodstock over a 12-week period. Fish were fed a commercial diet (control), and diets containing 2 and 5% krill meal (KM).

Table 2. Proximate composition of eggs from Nile tilapia broodstock fed on a commercial diet and on diets containing 2% and 5% krill meal (KM).

	Diet
Proximate composition (%, as–is)	Control	2% KM	5% KM
Dry matter	30.91	32.25	30.74
Crude protein	21.50	22.17	22.20
Crude fat	2.74	4.05	3.67
Total fiber	1.01	1.44	1.90
Ash	2.39	2.45	2.38

Table 3. Fatty acid profile (%, as-is) of diets and frozen tilapia eggs.

Fatty Acids	Composition (%, as-is basis)
	Diet			Eggs
	CTL	2% KM	5% KM	CTL	2% KM	5% KM
12:0	0.01	–	0,01	–	–	–
14:0	0.05	0.06	0.10	0.06	0.06	0.06
15:0	0.01	–	0.01	–	–	0.01
16:0	0.92	0.98	1.08	0.49	0.53	0.56
17:0	0.01	0.01	0.01	0.01	0.01	0.01
18:0	0.23	0.20	0.21	0.30	0.32	0.29
20:0	0.02	0.02	0.02	0.01	0.01	0.01
22:0	0.02	0.02	0.02	–	–	–
24:0	0.01	0.02	0.02	–	–	–
16:1	0.07	0.05	0.07	0.12	0.11	0.12
18:1n–7	0.08	0.09	0.12	0.09	0.09	0.10
18:1n–9	1.29	1.27	1.32	0.47	0.51	0.52
20:1n–9	0.01	0.02	0.02	0.02	0.03	0.02
22:1n–9	–	–	0.01	–	–	–
22:1n–11	–	0,01	–	–	–	–
18:2n–6	2.62	2.79	2.83	0.42	0.48	0.48
20:2n–6	–	–	–	0.03	0.04	0.03
18:3n–6	–	–	–	0.03	0.03	0.03
20:3n–6	–	–	–	0.04	0.05	0.04
20:4n–6	0.01	–	–	0.16	0.16	0.15
22:4n–6	–	–	–	0.06	0.07	0.06
22:5n–6	–	–	–	0.10	0.10	0.08
18:3n–3	0.26	0.23	0.27	0.04	0.03	0.05
20:3n–3	–	–	–	0.01	0.01	0.01
18:4n–3	0.01	0.02	0.05	–	–	–
20:5n–3	0.05	0.05	0.11	0.01	0.01	0.01
22:5n–3	0.01	–	0.01	0.05	0.05	0.05
22:6n–3	0.08	0.05	0.08	0.23	0.19	0.26
∑ n–3^1	0.41	0.35	0.52	0.34	0.29	0.38
∑ n–6^2	2.63	2.79	2.83	0.84	0.93	0.87
∑ SFA^3	1.28	1.31	1.48	0.87	0.93	0.94
∑ MUFA^4	1.46	1.45	1.55	0.70	0.74	0.76
∑ PUFA^5	2.89	3.04	3.15	0.57	0.64	0.64
∑ HUFA^6	0.15	0.10	0.20	0.61	0.58	0.61

^an-3, 18:3n–3, 20:3n–3, 18:4n–3, 20:5n–3, 22:5n–3, 22:6n–3.

^bn–6, 18:2n–6, 20:2n–6, 18:3n–6, 20:3n–6, 20:4n–6, 22:4n–6, 22:5n–6.

^cSFA, saturated fatty acids, 12:0, 14:0, 15:0, 16:0, 17:0, 18:0, 20:0, 22:0, 24:0.

^dMUFA, monounsaturated fatty acids, 16:1, 18:1, 20:1, 22:1.

^ePUFA, polyunsaturated fatty acids, 18:2n–6, 20:2n–6, 18:3n–6, 20:3n–6, 18:4n–3, 20:3n–3.

^fHUFA, highly unsaturated fatty acids, 20:4n–6, 20:4n–6, 20:5n–3, 22:4n–6, 22:5n–6, 22:5n–3, 22:6 n-3.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.