The influence of processing of soyabeans and sunflower seed on their energy and amino acid availability for poultry

[摘要] ENGLISH ABSTRACT:1. The effect of heat-treatment and dehulling of full-fat soya (Glycinemax) on AMEn' amino acid availability and broiler performance.Heat treatment and dehulling of full-fat soya were evaluated in terms of their effect onAMEn, apparent amino acid availability and broiler performance. Four products weretested: raw whole soya (RWS), raw dehulled soya (RDS), extruded whole soya(EWS) and extruded dehulled soya (EDS). Trials were conducted to determine AMEnvalues and apparent amino acid availability of the products. A 42-day broiler trial wasconducted to measure the effect of extrusion and dehulling on broiler performance.Test products were added to the diets at levels up to 263.2 g/kg in the starter diet and260.0 g/kg in the finisher diet. Results indicated that extrusion cooking improvedAMEn and apparent amino acid availability. This was reflected in the improvedperformance of broilers fed extruded soya as compared to raw soya. Increasingamounts of RWS and RDS led to decreases in mass and intake and poor feedconversion ratio (FeR) due to the presence of anti-nutritional factors. Broilers fedEWS were heavier, consumed more feed and had better FeR than those fed RWS orRDS. Dehulling improved AMEn (EWS: 13.75 MJ/kg vs EDS: 15.09 MJ/kg) andrendered a product with slightly higher levels of total amino acids. Broilerperformance did not reflect this as there was no difference in mass, intake or FeRbetween broilers fed increasing levels of EWS or EDS. Lysine and arginine were lessavailable in EDS than EWS indicating the possible over-cooking of EDS. Levels ofEWS and EDS of 263.2 g/kg in the starter and 260.0 g/kg in the finisher supportedmaximum broiler performance. 2. The effect of heat-treatment and dehulling of full-fat sunflower(Helianthus annuus) on AMEm amino acid availability and broilerperformance.Heat treatment and dehulling of full-fat sunflower were evaluated in terms of theireffect on AMEn, apparent amino acid availability and broiler performance. Fourproducts were tested: raw whole sunflower (RWSF), raw dehulled sunflower (RDSF),extruded whole sunflower (EWSF) and extruded dehulled sunflower (ED SF). Trialswere conducted to determine AMEn values and apparent amino acid availability of theproducts. A 42-day broiler trial was conducted to measure the effect of expansion anddehulling on broiler performance. Test products were added to the diets at levels up to115.0 glkg in the starter diet and 181.5 glkg in the finisher diet. Dehulling rendered aproduct with higher crude protein, ether extract, amino acid and AMEn values. AMEnwas only slightly improved by expansion. The AMEn values obtained were: RWSF:16.03 MJ/kg, RDSF: 18.87 MJ/kg, EWSF: 16.22 MJ/kg, EDSF: 19.49 MJ/kg.Dehulling had no effect on apparent amino acid availability. Expansion did not affectapparent amino acid availability of dehulled full-fat sunflower but had a negativeinfluence on apparent amino acid availability of whole sunflower seeds. Thishighlights the possible dangers of reduced protein quality as a result of overprocessing.No differences were observed in terms of mass, intake and feedconversion ratio of broilers fed any of the products during the 42-day broiler growthtrial. All products supported optimum broiler performance at levels up to 115.0 glkgin the starter diet. For the finisher diets, optimum performance was maintained atlevels of 181.5 glkg, for RDSF and EDSF, while performance of broilers fed RWSFand EWSF was optimal up to 145.2 glkg.

[发布机构] Stellenbosch University