Table 1.

Brief summaries of studies using chicks or turkeys included in this review. ¹ Article contained multiple experiments, and amounts for each group were averaged based on the number of experiments in which they appeared. X indicates information not applicable; “-” denotes missing or not enough information to calculate.

Reference	Silicon Form	Group	Daily Intake from Diet	Silicon Dose per Day	Total Silicon mg/kg BW	Animal	Age at Start	Results
Carlisle, 1972 [1]	Sodium metasilicate	Control	1 ppm	X	-	Chicks	1 day	Reduced growth rate, shorter leg bones with smaller circumferences and thinner cortices in control, control tibias and femurs fracture more easily
		Supplemented	100 ppm
Carlisle 1976 [6]	Sodium metasilicate	Control	<3 ppm	0 mg	-	Chicks	1 day	Better growth, higher hexosamine content and percent in articular cartilage, greater silicon content in comb, less water content in tibia and femur with supplementation, no difference in percent ash
		Supplemented		100 ppm
Carlisle, 1980a [4]	Sodium metasilicate	Control	1 ppm	X	-	Chicks	1 day	Greater percentage and total amount of hexosamine and greater percentage of collagen in tibias from supplemented vs control, Si-deficient tibias had lesions and changes in epiphyseal cartilage especially in proliferative zone
		Supplemented	250 ppm
Carlisle, 1980b [3]	Sodium metasilicate	Control	1 ppm	X	-	Chicks	1 day	Si-deficient skulls had less trabeculae and calcification, reduced collagen content
		Supplemented	250 ppm
Carlisle, 1981 [37]	Sodium metasilicate	Control	1 ppm	X	-	Chicks	1 day	Skull abnormalities in Si-deficient chicks from less collagen concentration in bones
		Supplemented	250 ppm
Merkley and Miller, 1983 [38]	Sodium metasilicate	Control	-	X	-	Chicks	1 day	Humeri strength decreased during immobilization in control but remained similar to unrestricted humeri strength with metasilicate
		Sodium metasilicate		74 ppm
Watkins, Vagnoni, and Southern, 1989 [39]	Sodium zeolite A	0%	-	0 mg	-	Chicks	4 days	SZA with excess Ca decreased weight gain and tibia ash
		0.75%		90.3 mg
Elliot and Edwards, 1991 [40]	Sodium metasilicate	Basal 1	0.01 mg	0 mg	0.02	Chicks	1 day	High silicon inclusion reduced feed efficiency, no difference in tibial ash
		25 1		0.20 mg	0.66
		50 1		0.46 mg	1.53
		150 1		1.44 mg	4.78
		250 1		2.72 mg	7.62
Watkins and Southern, 1992 [41]	Sodium zeolite A	0% SZA	-	X	-	Chicks	4 days	Plasma Ca or alkaline phosphatase unaffected by SZA, reduction in plasma P but increase in tibia Mn, Zn, Cu, and Al with SZA
		0.75% SZA
Scheidler, 1993 [42]	Aluminosilicates	Control	-	X	-	Chicks	1 day	Novasil increased bone ash, Ethacal decreased bone ash, supplementation decreased serum Cl
		Ethacal	163 mg		279
		Novasil	288 mg		506
		Perlite	357 mg		543
		Zeobrite	333 mg		514
Kayongo-Male and Julson, 2008 [26]	Tetraethyl-orthosilicate	Groups based on supplemented Si levels		0 ppm	-	Turkeys	1 day	Moment of inertia and plasma calcium lower with high supplementation, no differences in other physical or mechanical properties
				135 ppm
				270 ppm
				540 ppm
Sgavioli et al., 2016 [30]	Not given	0 mg Supplement	-	X	-	Chicks	1 day	Si supplementation had no effect on bone density or breaking strength, bone ash, phosphorus, zinc, and manganese increased without increasing bone calcium
		0.5 mg Supplement		244 mg	150
		1.0 mg Supplement		488 mg	300
		1.5 mg Supplement		740 mg	450
Scholey et al., 2018 [32]	Monomeric silicic acid	Control 1	55.8 mg	X	114	Chicks	1 day	Improved tibia breaking strength and tibial Si at 1000 mg/L supplementation, foot and tibia ash increased in the 500 mg/L, no other significant differences in bone measures
		200 mg/L		16.2 mg	138
		500 mg/L		39.5 mg	166
		1000 mg/L 1		79.5 mg	280
Pritchard et al., 2020 [43]	Orthosilicic acid	Control	2.9 mg	X	4.1	Chicks	1 day	Supplementation reduced serum boron and increased serum calcium; bone density, morphology, and strength measures were similar among groups
		Normal		133 mg	147
		High		804 mg	863