Table 2.

Studies on the effect of consumption of hydrolyzed collagen in animal models.

Collagen	Animal Model	Period	Dose/day	Result	Reference
Type I - H	Male C57BL/6J mice (OA)	12 Weeks	Standard feed plus Type I–H bovine (200 Da) 3.8 mg or 38 mg	↑cartilage area; ↑chondrocytes; ↑proteoglycan matrix; ↓apoptosis; ↓MMP13 protein; ↓synovial hyperplasia and TnfmRNA; ↓inflammation	[46]
HC	Three months of age female Wistar rat (OVA)	8 Weeks	Standard diet formulated according to AIN 93-M plus 5 or 10 times the recommended human consumption of HC calculated according to rat weight, dietary protein content 13.15% and 14.30%	↑bone mass; ↑osteocalcin; ↑mechanical strength of the vertebrae; ↑vertebrae protein content	[47]
HFC	Five-week-old male Wistar rat in growth phase undergoing exercises	11 Weeks	Diet with 20% protein, 30% HC (1 KDa) or diet with 40% protein, 30% HC (1 KDa)	↑bone mass; ↔bone strength; ↑ exercise effect	[48]
CP	Eight-week-old maleSprague-Dawley rats (OA)	12 weeks	Gavage 0.8 g/kg.bw or 1.6 g/kg.bw Atlantic salmon (Salmo salar) CP	↓serum IL-6 and IL-17; ↓ cartilage IL-1βand TNF-α; ↓cartilage degeneration	[49]
HC	Nine-week-old female Hos:HR-1 hairless mice exposed to UV-B irradiation	11 days	Gavage 2.0 g/kg.bw of fish scale HC	↓ TEWL on days 2, 3, and 4	[50]
		7 weeks	Diet with 2 g of fish scale HC per 100 g of the AIN-93G diet	↓ TEWL at weeks 4 and 6; ↑ water content at weeks 2, 4, and 6; ↑ skin elasticity at week 6; ↑ dermal hyaluronic acid content
CTP	Five-week-old female hairless mice (SKH-1) exposed to UV-B irradiation	14 weeks	Gavage 167 mg/kg/day or 333 mg/kg/day	↓ wrinkle formation induced by UVB irradiation; ↓ collagenase (MMP3 and -13) and gelatinase (MMP-2 and -9); ↓ skinfold thickness; ↑ skin hydration; ↑ collagen fibers and hydroxyproline; ↑ skin elasticity; ↓ erythema formation	[51]