ABSTRACT
This research was designed to determine the nutritive value of rubber leaf protein concentrates and bagasse and their utilization in feeding growing rabbits.
The research was carried out in four (4) studies. In the first study, freshly harvested rubber leaves from four (4) locations (2 in Edo State and 2 in Delta State) were processed into leaf protein concentrate (RLPC), bagasse (RLB) and whey using the heat coagulation method. The physical characteristics of the three products were determined, proximate and some mineral compositions of RLPC and RLB, some anti-nutrient factors as well as some functional properties of rubber leaf protein concentrates were determined. In study two (2) and three (3), six experimental diets each were formulated to contain 18% crude protein and 2700kcal/Kg metabolisable energy with weight-for-weight replacement of SBM with RLPC and wheat offal with RLB respectively at 0%, 20%, 40%, 60%, 80% and 100%, with 36 growing rabbits each were fed and watered ad libitum for 12 weeks. In the fourth study, seven (7) experimental diets were formulated; RLPC/RLB replaced SBM and wheat offal at 0%, 30/60%, 40/60%, 50/60%, 30/100%, 40/100% and 50/100% respectively. 42 growing rabbits with mean weight of 590 – 680grams were used for this experiment. The animals used in the feeding trials were randomly allocated to the different dietary treatments, each rabbit making a replicate. Feed and water were provided ad libitum for the duration of the feeding trials (12 weeks) after which data were collected on the performance, blood and serum composition, carcass characteristics and economy of feed conversion.
Results from experiment one reveals that the proximate and some mineral composition of RL, RLPC and RLB were significantly (p<0.05) affected by Locations. The highest CP value for RLPC was obtained in Location A (Benin City) while the highest for bagasse was obtained from location D (Oghara). The phytochemical analysis revealed that RLPC contained 5.16% Tannin, 8.34% Saponin, 10.60% Alkaloids, 0.18mg/100g Oxalates, 89.23mg/100g flavonoids, and 81.10mg/100g Phytin. The functional properties were examined and found to be at par with what is reported in literature for most protein sources, thus making it possible for their inclusion in food systems. The growth performance of rabbits fed RLPC and RLB based Diets showed significant (p<0.05) differences for feed intake, weight gained, water intake and feed to water ratio across the different dietary treatments. Rabbits fed Diet 3 which contained 40% RLPC and Diets 6 which contained 100% RLB respectively recorded significantly (p<0.05) higher growth and economic performances. The haematological and serum biochemical components of the test animals in these studies were significantly (p<0.05) affected by the different test diets, the PCV and Hb reduced as the level of RLPC increased. The carcass cuts, dressing percentage and some organs measured in Experiments 2, 3 and 4 showed significant (p<0.05) differences, thereby indicating that the inclusion of RLPC, RLB and RLPC/RLB in the diets affected these organs and cuts. The cost of feed and economy of feed conversion showed that there was a decrease in the cost of formulating the different test diets from ₦94.40 to ₦87.60, ₦94.40 to ₦92.02 and ₦94.40 to ₦86.70 for experiment 2, 3 and 4 respectively. The growing rabbits fed RLPC/RLB as replacement for SBM/wheat offal at 30/60% gave a better growth and economic performance. It can therefore be recommended that rubber leaf protein concentrate and rubber leaf bagasse can be used to replace up to 40% and 100% of soyabean meal and wheat offal, 30 and 60% in combination respectively in growing rabbit diets.
