Growth indices, haematological parameters, carcass attributes and economics of production of rabbits fed graded levels of kolanut testa

Abstract

The cost of feed is the main cause of high cost of production of rabbits. Kolanut testa, a protective covering of the kolanut seed (Cola nitida) is readily available as by-product in areas where kolanut is produced. Thus, the objective of this study was to assess the growth performance, carcass attributes, haematological parameters and economics of production of rabbits fed diets with varying inclusions levels of kolanut testa (KOT) as replacement for maize. Thirty mixed breed rabbits of mixed sexes were used for this experiment. The rabbits were randomly allotted into 5 treatment groups. Five experimental diets were formulated such that KOT replaced maize at 0, 10, 20, 30 and 40%. Records of feed intake and weight gain were properly taken and blood samples were collected and analysed for their haematological parameters at the end of the experiment. Cost analysis using dedicated formulae was done to determine economics of production. The experiment lasted for eight weeks. Data were analyzed using Analysis of Variance. No significant (P>0.05) difference was recorded in all the parameters measured to determine growth performance. The same applies to parameters measured for carcass attributes except for weight of limbs. Significant (P<0.05) difference was however recorded among mean values of PCV (28.67-36.33%), RBC (3.14-4.12x10⁶/mm³), WBC (3.10-5.87x10³/mm³) and Mon (1.40-1.67%) of the experimental animals. Cost of feed decreased with increase in KOT inclusion (₦139.8- ₦112.54). Cost of feed (₦/kg) weight gain (₦1023.61-₦583.04); cost of weight gain (₦573.22-₦483.92); and total cost (₦2143.61-₦1523.92) all followed similar pattern. Cost differential (205.93–440.04) and relative cost benefit (20.11–43.04%) increased with increase in the level of replacement of KOT. Conclusively, growth performance was not negatively affected and total weight gain was numerically highest at 40% (916.67g) with no deleterious effect on the health of the rabbits. Also, the highest relative cost benefit was recorded at 40% (28.54%). These prove that KOT is a viable substitute for maize in rabbit diet and it is more economical at 40% replacement level.