Main and interaction effects of extrusion temperature and usage level of full fat soybean on performance and blood metabolites of broiler chickens
The extruded full fat soybean (EFFSB) may be used in diet to satisfy the energy and protein requirements of fast growing broiler chickens. The main and interaction effects of three extrusion temperatures and two dietary levels of FFSB were studied on the performance, physiological enzymes and blood metabolites of broiler chickens from 0 to 42 days. The batches of full fat soybean (FFSB) were wet extruded at three temperatures (145, 155 and 165°C, respectively) for 15 s. 240 day-old Ross 308 male broiler chicks were divided and placed in 24 pens. Six starter, grower and finisher diets were provided in a 2 × 3 factorial design with two dietary levels of EFFSB (7.5 and 15%) and three extrusion temperatures (145, 155 and 165°C). The extrusion temperatures did not have significant effect on feed intake (FI), body weight gain (WG) and feed conversion ratio (FCR) of chickens during each and whole period, but the inclusion rate of EFFSB had significant (P<0.05) effect on FI and WG. The FI and WG of chickens fed diet contained 15% EFFSB was significantly (P<0.05) lower than those fed 7.5% EFFSB diet. The extrusion temperatures and inclusion rate did not significantly affect pancreas weight, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes, indicating that the anti-nutrients residuals of FFSBs extruded at 145, 155 and 165°C did not influence liver system and pancreas size of chicks at 21 days of age. The interaction effects between dietary levels of EFFSB and extrusion temperatures on performance criteria, pancreas weight, CPK, LDH, AST and ALT enzymes of chickens were not significant (P>0.05) during each and whole period. It is concluded that blood metabolites and broiler performance were not affected (P>0.05) with extrusion temperature from 145 to 165°C, but increasing dietary levels of EFFSB from 7.5 to 15%, affected (P<0.05) negatively the growth rate of chicks.
Key words: Full fat soybean extrusion, temperature, broiler performance, blood metabolites.