Table 2.

Dietary supplementation of vitamin A on production performance of poultry.

Parameter	Species	Dietary Supplementation	Effect	Reference
Feed Intake
	Layers	9000 IU/kg	Increased	[31]
	Layer	5000 IU/kg (T5) to 25,000 IU/kg (T25)	No effect	[35]
	Layer	16,000 IU/kg	Increased	[37]
	Broiler	0 or 3000 IU/kg	Decreased	[38]
	Broiler	5000 IU/kg	Increased	[29]
	Layers	8 mg/kg canthaxanthin	Increased	[43]
Body weight
	Broilers chicks	15,000 IU/kg	Increased	[44]
	Layer	16,000 IU/kg	Increased	[37]
	Growing Ducks	Above 2500 IU/kg	Decreased	[45]
	Growing Ducks	0 to 2500 IU/kg	Increased	[45]
	Broiler	2645 to 7935 IU/kg	Decreased	[46]
	Broiler	35,512 and 65,512 IU/kg	Decreased	[47,48]
	Broiler	0 or 3000 IU/kg	Decreased	[38]
Carcass traits/Meat quality
Drip loss	Broiler	10,00,000 IU/kg	Decreased	[49]
Shear force	Goslings	21,600 IU/kg	Increased	[29]
pH	Breeder laying hens	9000 IU/kg	Increased	[50]
pH	Broilers chicks	40 mg/kg lycopene	Increased chick body weight	[51]
Redness	Broiler	15,000 IU/kg	Increased	[44]
Carcass traits	Broiler	3208~6208 IU/kg	Increased	[52]
Carcass quality	Broiler	10,000 IU/kg	Increased	[53]
Relative liver weight		15,000 IU per kg	Decreased	[54]
Hatchability and reproduction
Hatching performance	Broiler	Overdose	Decreased	[55]
Hatchability	Broiler	10,000 to 15,000 IU/kg	Decreased	[56]
Reproductive performance	Layer	12,000 IU/kg	Increased	[38]
Hatchability and reproduction	Layers	16,000 IU/kg	Increased	[37]
Hatching capacity	Layers	9000 IU/kg	Increased	[31]
Egg yield and quality
	Layers	9000 IU/kg	Increased	[31]
	Layer	5000 to 25,000 IU/kg	No effect	[35]
	Layer	210,000 and 410,000 IU/kg	Decreased	[57]
	Layer	16,000 IU/kg	Increased	[37]
Egg production	Layer	Overdose	Decreased	[55]
Egg production	Layers	24,000 IU/kg	No effect	[58]
Laying performance	Layers	9000 IU/kg	Increased	[31]
Egg yield	Broiler	10,000 to 15,000 IU/kg	Decreased	[56]
Egg yield	Layers	24,000 IU/kg	No effect	[58]
Efficiency of vitamin A transfer from diet to egg	Layer	8000 IU/kg	No effect	[59]
Egg production	Layer	210,000 and 410,000 IU/kg	Decreased	[57]
No. of eggs produced	Layer	16,000 IU/kg	Increased	[37]
Egg size	Broiler	10,000 to 15,000 IU/kg	Decreased	[56]
Egg production	Layer	5000 to 25,000 IU/kg	No effect	[35]
Egg yolk mass and egg weight	Layers	8 mg/kg canthaxanthin	Increased	[43]
Egg yolk CX concentration	Broiler breeders	6 mg/kg canthaxanthin	Increased	[60]