Effects of dietary n-3 polyunsaturated fatty acids and ... - FINS

1 st WorkshopXIII International Feed Technology SymposiumDISCUSSIONAlthough starch has been considered to be an adhesive agent when processed [7], thecurrent results show that addition of native starch does not improve pellet durability evenfor diet with very poor durability. Addition of pre-gelatinised starch did result in increaseof pellet durability within starch containing diets, which is in agreement with Wood [12],but was still inferior to non-starch diets. The positive effect of pre-gelatinised starchindicates that starch has a potential to act as a binder if gelatinised [10, 12]. It isreasonable to assume that the binding properties observed for non-starch diets is causedby the proteins in the diet, as Briggs et al. [1] found a positive correlation between pelletdurability and increased protein content in the diets. This is further supported byWinowiski [11] where a dramatic increase in pellet durability was observed byincreasing overall protein content by addition of wheat.A considerable increase in pellet durability for steam-pelleted diets compared to coldpelleteddiets is consistent with earlier research [8] where a positive effect of steamconditioning on physical pellet quality was observed. The starch gelatinisation dataconfirm previous observations that the limited water content and moderate temperaturesduring the pelleting process does not give any extensive starch gelatinisation [9].REFERENCES1. Briggs, J. L., Maier, D. E., Watkins, B. A., Behnke, K. C: Effect ofingredients and processing parameters on pellet quality. Poultry Science 78(1999), 1464-1471.2. Gill, C: Back to basics of growth. Feed international 24 (2003), 6-9.3. Gilpin, A.S., Herrman, T.J., Behnke, K.C., Fairchild, F. J: Feed moisture,retention time, and steam as quality and energy utilization determinants in thepelleting process. Applied Engineering in Agriculture 18 (2002), 331-338.4. Hilton, J.W., Cho, C.Y., Slinger, S. J: Effect of extrusion processing andsteam pelleting diets on pellet durability, pellet water absorption and thephysiological response of rainbow trout. Aquaculture 25 (1981), 185-1945. Payne, J., Rattink, W., Smith, T., Winowiski, T: Objectives in pelleting. In:Payne, J., Rattink, W., Smith, T., Winowiski, T. (Eds), The PelletingHandbook. Borregaard Lignotech, Norway, (1994), pp.11-12.6. SAS Inc., 1999-2001. SAS User’s Guide: Statistics, Version 8.2 Edition. SASInc., Cary, NC, USA.7. Schwartz, J. B., Zelinskie, J. A: The binding and disintegrant properties of thecorn starch fractions: amylose and amylopectin. Drug Dev. Ind. Pharm. 4(1978), 463-483.8. Skoch, E. R., Binder, S. F., Deyoe, C. W., Allee, G. L., Behnke, K. C:Effects of pelleting conditions on performance of pigs fed a corn-soybean mealdiet. J. Anim. Sci. 57 (1981), 922-928.9. Svihus, B., Kløvstad, K. H., Perez, V., Zimonja, O., Sahlström, S., Schüller,R. B., Jeksrud, W. K., Prestløkken, E: Nutritional effects of pelleting ofbroiler chicken diets made from wheat ground to different coarsenesses by the49