Effect of improved pellet quality from the addition of a pellet binder and/or moisture to a wheat-based diet conditioned at two different temperatures on performance, apparent metabolisable energy and ileal digestibility of starch and nitrogen in broilers

Abstract

The effect of a commercial pellet binder and/or moisture addition on pellet quality and performance, apparent metabolisable energy and ileal digestibility of starch and nitrogen of broilers fed wheat-based diets conditioned at two different temperatures was examined in this study. Broiler starter (d 1–21) and finisher (d 22–35) diets were formulated and subjected to one of the six following treatments: Treatment 1, basal diet conditioned at 60°C; Treatment 2, 3g/kg commercial pellet binder added to the basal diet prior to conditioning at 60°C; Treatment 3, 24g/kg moisture added to the basal diet prior to conditioning at 60°C; Treatment 4, 3g/kg commercial pellet binder plus 24g/kg moisture added to the basal diet prior to conditioning at 60°C; Treatment 5, basal diet conditioned at 90°C; Treatment 6, 3g/kg commercial pellet binder added to the basal diet prior to conditioning at 90°C. Among starter diets, the diet conditioned at 90°C with pellet binder had the highest gelatinised starch content followed by the diet conditioned at 90°C without pellet binder. Starter diet conditioned at 60°C with no pellet binder or moisture addition had the lowest resistant starch content compared to other dietary treatments. Finisher diets conditioned at 90°C without or with pellet binder had the highest gelatinised starch content. In starter and finisher diets conditioned at 60°C, moisture addition, individually or in combination with pellet binder, resulted in higher pellet durability index and pellet hardness compared to the diets without or with pellet binder. Starter and finisher diets conditioned at 90°C with pellet binder had the highest pellet hardness followed by the diets conditioned at 90°C without pellet binder. Steam-conditioning at 90°C, regardless of pellet binder addition, resulted in lower apparent metabolisable energy compared to all diets conditioned at 60°C. Dietary treatments had no effect (P>0.05) on the coefficient of ileal apparent digestibility of starch and nitrogen in finisher diets. During the starter period (d 1–21), pellet binder and/or moisture addition to the diets conditioned at 60°C had no effect (P>0.05) on performance parameters compared to the diet conditioned at 60°C with no pellet binder or moisture addition; however, pellet binder addition to the diet conditioned at 90°C increased (P<0.05) weight gain and feed intake and improved (P<0.05) feed per unit gain compared to the diet conditioned at 90°C with no pellet binder. During the finisher period (d 22–35), dietary treatments had no effect (P>0.05) on performance parameters. Over the whole trial period (d 1–35), birds fed the diet conditioned at 90°C without pellet binder had lower (P<0.05) weight gains than those fed the other dietary treatments. Overall, these results illustrate possibilities for high quality pellets to be manufactured through the addition of pellet binder and/or moisture without the need for high conditioning temperatures.