Age-related changes in meat tenderness and tissue pentosidine: Effect of diet restriction and aminoguanidine in broiler breeder hens

The nonenzymatic glycosylation of tissue protein contributes to the formati on of crosslinks that leads to structural and functional deterioration in t he long-lived tissue protein, collagen. The accumulation of these crosslink s thus contributes to the objectionable toughness of meat from aged animals , decreases its economic value, and limits its use in whole muscle foods. T he objectives of this study were to determine the effectiveness of diet res triction and the crosslinking inhibitor, aminoguanidine (AG), on reducing t he accumulation of crosslinks, thereby improving meat tenderness in broiler breeder hens. The glycoxidation product, pentosidine, was also measured in skin (Ps) to determine whether changes in its concentrations correlated wi th the changes in shear value (SV). Chicks (n = 450) were randomly assigned to four treatment groups from 8 to 125 wk after hatch: acl libitum (AL), d iet restricted (DR), AL and DR groups supplemented with 400 ppm AG each (AL +AG and DR+AG, respectively). Sheer value was measured with an Instron Univ ersal Mechanical Machine. Skin Fentosidine was isolated by reverse phase HP LC. There was an age-related, linear increase in SV (P < 0.0001, r = 0.96), which correlated (r = 0.86) with the age-related increase in Ps in AL hens . Diet restriction retarded SV (P < 0.0001) over the sampling period. bn ge neral, SV values for AL+AG were similar to those measured in DR, whereas no additive effect was observed for AG in DR birds. It was concluded that the re was a linear increase in meat toughness (SV) with age that correlates wi th the accumulation of Ps, and that the decline in meat tenderness can be r etarded by DR or AG. Secondly, the effect of DR on accumulation of Ps was s o pronounced that AG supplementation did not further enhance this effect.