Changes in the chemical composition of rabbit meat during growth

Relative growth rates of water, fat and protein by means of the allometric equation and changes in chemical composition of total meat, meat from hind leg and M. longissimus lumbaris from 1 to 20 weeks of age were studied in 320 rabbits of two strains (New Zealand White and California) and both sexes. All the chemical components showed changes in their allometric coefficients which determined variations in their relative percentages (P < 0·001) during the experimental period. Protein was characterized by a positive allometry although its rate of deposition decreased from 3-4 weeks of age. Water exhibited an important decrease in rate of deposition, passing from positive to negative allometry while, almost simultaneously, the rate of deposition of fat increased, passing from negative to positive allometry; nevertheless, the moment of change of these two components differed among the parts chemically analysed. All these changes were concentrated in a short interval of ages (3-7 weeks of age) that coincided with the one found for anatomic components of the carcass in a previous work (Deltoro & López, 1985). Significant differences (P < 0·001) for mean values were obtained among parts chemically analysed and, to a lesser degree, between lines and sexes. Meat from hind leg and M. longissimus lumbaris had a higher content of protein and a lower content of fat than the rest of the carcass meat. Relating the results to fat-free matter decreased differences but remained significant in most cases and indications of having attained chemical maturity at the end of the experimental period were obtained.