Table 1.

Ingredient compositions and nutrient levels of experimental diets¹ for parental pigeons² (on as-fed basis).

Items	Control	LA1%	LA2%	LA4%
Ingredients of a whole-grain form feed (%)
Corn	56.27	56.27	56.27	56.27
Pea	28.12	28.12	28.12	28.12
Wheat	5.63	5.63	5.63	5.63
Sorghum	5.63	5.63	5.63	5.63
Rapeseed oil	4.35	3.26	2.17	0
Linoleic acid	0	1.09	2.18	4.35
Total	100.00	100.00	100.00	100.00
Calculated nutrients3 (%)
Metabolizable energy (MJ/kg)4	13.84	13.84	13.84	13.84
Crude protein	12.63	12.63	12.63	12.63
Analyzed linoleic acid	1.82	2.75	3.68	5.53
Ingredients of grit meal (%)
Limestone	52.93	52.93	52.93	52.93
Shell meal	28.10	28.10	28.10	28.10
Yellow mud	14.05	14.05	14.05	14.05
Salt	1.41	1.41	1.41	1.41
Ferrous sulfate (monohydrate)	0.23	0.23	0.23	0.23
Premix5	3.28	3.28	3.28	3.28
Total	100.00	100.00	100.00	100.00
Calculated nutrients2 (%)
Calcium	27.79	27.79	27.79	27.79
Phosphorus	0.01	0.01	0.01	0.01
Sodium	0.03	0.03	0.03	0.03
Chlorine	0.59	0.59	0.59	0.59
Ferrum	0.30	0.30	0.30	0.30

¹Control, control group; LA1%, 1% linoleic acid addition group; LA2%, 2% linoleic acid addition group; LA4%, 4% linoleic acid addition group.

²All feeds were fed in a whole-grain form at 07:00 and 15:00 h every day, and grit meal was offered to the birds on a continuous basis.

³Nutrient values were calculated from tables of feed composition and nutritive values in China (28th edition, 2017).

⁴Metabolizable energy values determined in pigeons were calculated from those reported for chickens in accordance with a previous study (the study by Hullar et al., 1999), which observed that the metabolizable energy values of feed in pigeons did not differ significantly from those in chickens.

⁵The premix provided the following per kg of diet: vitamin A, 5,000 IU; vitamin E, 50 IU; vitamin D₃, 2,000 IU; copper sulfate, 15 mg; manganese sulfate, 45 mg; zinc sulfate, 90 mg.