EFFECTS OF DIFFERENTLY PROCESSED SOYABEAN AND BIRD’S AGE ON GROWTH AND PRE-CAECAL NUTRIENT DIGESTIBILITY OF BROILER CHICKENS

Abstract

Three phase experiments were carried out to assess the nutritive value of differently processed soyabean meal (SBM) and effect of age of broiler on performance, pre-caceal amino acid digestibility, haematology, carcass traits, relative organ's weightand muscle measurement of broiler chicken. The first experiment was conducted using broilers age: 0 -3 weeks while the second and the third experiments were conducted with birds age 4-6 and 6-8weeks, respectively. The 3 experimental diets contained each of the 3 differently processed soyabean meal, cooked soyabean for diet A, while roasted and defatted soyabean meal were used in diets B and C respectively at the same level of inclusion of 25% in each phase. Titanium oxide was included as indigestible maker. Digesta was sampled on a pen basis from the section of the gastro-intestinal tract between Merkel's diverticulum's and 2cm anterior to the ileo caeca coleonic junction (ICCJ). The digesta samples were dried and analyses for proximate composition and energy content. Ttitanim oxide and amino acid composition were also analysed. The variation that occurred in the proximate composition among defatted, cooked and roasted soyabean indicated that considerable differences can occur in the nutrient composition if different process method are employed with respect to crude protein defatted soyabean (43.12%) was the best while cooked soyabean (42.0%CP) was the lowest and vice versa for energy content. The feed intake (FI), dry matter intake.(DMI), crude protein intake(CPI), nitrogen free extract intake (NFEI), Ash intake (AI) and gross energy intake (GEI) were significantly (P<0.001, P<0.05) affected by the SBM processing methods and age of birds. The feed intake was highest with birds fed defatted soyameal at 0-3th week (31.87g/chick/day) and at 4-6th week (95.71g/chick/day) with corresponding highest average weight gain (44.33 and 130.38g/chick/day, respectively). While at 7-8th week of age the FI was lowest in birds fed defatted soyabean (121.19g/chick/day) and highest in birds fed roasted soyabean (146.08g/chick/day) with birdsfed cooked soyabean having the lowest weight gain (217.94g/chick/day). The interactions between birds age and SBM processing methods for all the nutrients except the fat intake and GEI were significant (P<0.01; 0.001). Age of birds influenced (P<.01; 0.001) amino acid (AA) intake except lysine, histidine, proline, glutamic acid,cystine, valine, isoleucine, tyrosine and phenylalanine while SBM processing methods significantly(P<0.01) influenced intake of most of the amino acids studied except proline, glatamic acid, cystine and methoinine.Only the broilers age x SBM processing methods of the intake of proline and cystinewere not significant. The digestibility co-efficient (DC) were significantly (P<0.01; 0.001) influenced by processing methods for all the AAs studied except threonine, glutamic acid and valine. The interaction between age of birds and SBM processing methods were significant (P<0.05, 0.01; 0.001) for all AA except histidine and valine. The SBM processing methods significantly (P<0.05; 0.001) influencedPCV, ESR, lymphocyte, monocytes and Basophil, while age of birds significantly (P<0.001; 0.01) influenced the PCV, ESR, RBC, neutrophil, monocytes and basophil. However, age of birds x SBM processing methods was significant (P<0.001) for PCV, Hb, ESR, Lymphocyte, Neutrophil and Monocytes. It could be concluded that processing methods employed for soyabean meal and age of broilers are important factors, which should be put into consideration when SBM is to be used in feed formulation. However, with respect to feed utilization defatted soyabean meal could be recommended for birds of 0-3weeks of age while roasted soyabean meal and cooked soyabean meal would be better for birds of ages 4-6th week and 7-8th week, respcetivley.