Growth Performance, Phenotypic Correlation Between Live Body Weight and Carcass Characteristics in Captive Male and Female African Giant Rats (Cricetomys Gambianus).

Abstract

This study was conducted to investigate some growth performance parameters, determine phenotypic correlation estimates between live body weight and carcass traits (dress weight, kidney, liver, tail, foreleg, thoracic, loin, hind leg, dressing percentage), and to predict the weight of carcass parts from live body weight in both sexes of African giant rats (AGRs). Forty (20 bucks and 20 does) African giant rats (Cricetomys gambianus) aged 3-4 months were used in the study; and data collected analyzed using t-test, Pearson’s correlation, and linear regression models embedded in GenStat Eleventh Edition. Growth performance measurements (feed intake, feed conversion ratio, body weight gain); and live weights were taken bi-weekly up to the 22nd week. The African giant rats were raised to the eleventh month before data on carcass performance were obtained. Results obtained showed that sex did not significantly (p>0.05) influence average daily feed intake, and feed conversion ratio but the male African giant rats had significantly (p<0.05) better bi-weekly body weight gain from the 8th week to the 22nd week and final body weight than the females. Sex had no significant influence (p>0.05) on protein, fat, moisture and pH of meat; except ash content which females had a higher percentage than their male counterparts. There was a significant (p<0.05) sex difference for carcass primal cuts (dressed, loin, foreleg, hind leg, thoracic weights) with male performing better than the females, however females recorded a heavier kidney weight than the males. There was no significant difference (p>0.05) in sexes for dressing percentages. The results also showed a significant positive correlation between live body weight and dressed weights in both males (r=0.9517, p<0.01) and females (r=0.8367, p<0.01). Similarly, significant positive correlations were observed between live body weight and almost all carcass cuts in both sexes. However, the highest positive correlation coefficients with primal cuts were observed in thoracic weight as (r=0. 9544), and (r = 0.9892) in males and females respectively. All the carcass traits recorded high values of adjusted coefficient of determination (R2) which were significant (p˂0.05) in males and females for predicting carcass cut traits from live body weight, but higher for pooled sex (p<0.01). In conclusion, live body weight can be used as an indirect selection criterion and predict carcass traits in both sexes of African giant rats.