Effects of segregation and impact of specific feeding behaviour and additional fruit on voluntary nutrient and energy intake in yellow-shouldered amazons (Amazona barbadensis) when fed a multi-component seed diet ad libitum

Abstract

Parrots are commonly fed multi-component seed diets; however, both segregation and feeding behaviour might alter ingredient and nutrient composition of the offered diet. First, the nutritional impact of segregation was assessed as it occurs when multi-component diets are temporarily stored in food containers that are replenished before completely emptied and birds being fed from the upper layer. The most detrimental effect hereof was a vast decrease in mineral supplements, leading to a decrease in Ca:P ratio in the offered food in relation to the formulated diet. Next, caloric distribution shifted towards more EE energy at the expense of NFE energy, as proportion of oilseeds increased and NFE-rich seeds decreased. Next, a feeding trial was performed on six yellow-shouldered amazons (Amazona Barbadensis) in which nutritional impact of parrot-specific feeding behaviour was assessed as well as the influence of additional provision of fruit next to the seed mixture. Profound selective feeding behaviour and dehusking of seeds resulted in a vast increase in energetic density by up to 64% in the ingested fraction in relation to the offered mixture in toto. Furthermore, the already suboptimal Ca:P ratio further deteriorated and caloric distribution shifted by over twofold towards EE energy accompanied with a vast decline in NFE energy, CP energy remaining similar. Finally, provision of fruit next to the seed diet significantly lowered voluntary energy intake from 936 ± 71 to 809 ± 109 kJ ME/kg(0.75)/day, without compromising adequate protein intake. In conclusion, notwithstanding efforts of nutritionists to formulate diets to approximate estimated, species-specific requirements, nutritional composition of the actually consumed fraction of multi-component seed diets can be vastly deteriorated by both animal and management factors. Furthermore, offering of fruit next to a seed-based diet effectively reduces voluntary energy intake and can hence be applied to abate obesity.