Effect of starch gelatinisation on nutrient digestibility and plasma metabolites in pigeons

Abstract

Feed manufacturing exerts physical and chemical changes in ingredients, including the gelatinisation of starch. Studies on the effect of the degree of starch gelatinisation on nutrient digestibility, metabolism and subsequent performance show inconsistent results, and no data are available in pigeons. In a cross-over trial, fourteen adult pigeons were randomly divided into two groups, in which two extruded pellet diets were tested. Both the diets were similar in ingredient composition and nutrient content, but differed in extrusion conditions, resulting in a different degree of starch gelatinisation: pellets with high gelatinisation degree (HG; 73.6% gelatinisation) and low gelatinisation degree (LG; 53.1% gelatinisation). After a 14-day adaptation period, all excreta were gathered per bird during a 5-day collection period. Coefficients of apparent digestibility of dry matter (DM), crude protein (CP), ether extract (EE), crude fibre (CF), crude ash (CA) and nitrogen free extract (NFE) as well as apparent nitrogen retention were calculated from proximate analyses of feed and excreta. Further, excreta consistency was subjectively scored. Blood samples were taken at the end of each period and plasma samples were analysed for glucose, fructosamine and triglycerides. Feed intake and body weight changes were recorded weekly. The apparent digestibility coefficients (ADCs) of DM, OM, CP, EE, CA and NFE were significantly higher in the LG group (p < or = 0.05). The ADC of crude fibre was numerically higher in the LG group but not significant, and no significant differences were found in starch digestibility. Excreta consistency score tended to be higher in the LG diet group. Neither plasma glucose nor plasma fructosamine values were significantly different between the two test diets. The results of this study show that lower degree of starch gelatinisation in extruded diets can enhance digestibility in pigeons.

The effect of starch gelatinisation degree on intestinal morphology, intestinal pH and bacteriology in pigeons

“…Body weight increase tended to be higher with low starch gelatinisation degree in time, despite similar feed intake. Comparable results were found in our previous study (Abd El‐Khalek et al., 2009).…”

“…The reduction in the pH in crop and gizzard through mild starch gelatinisation supports earlier findings that lower starch gelatinisation degree enhances nutrient digestibility in pigeons (Abd El‐Khalek et al., 2009). The mechanism involved might be similar to the use of carbohydrase enzymes: Jozefiak et al.…”

“…The reduced organ weights were probably a consequence of the increased efficiency of digestion in our previous study (Abd El‐Khalek et al., 2009). Similarly, the experiments of Brenes et al.…”

Micromineral Source Affects Intestinal Morphology but not Feather Formation in Pigeons

“…Recently, crude ash digestibility-as a measure of mineral absorption-showed a considerable increase due to decreasing the degree of starch gelatinisation of a complete extruded diet for pigeons [18]. A consecutive trial indicated that intestinal pH and changes in intestinal morphology might attribute to this phenomenon [19].…”

Feed processing effects on digestibility, palatability, excreta fermentation products and blood parameters in blue‐fronted amazon parrots (Amazona aestiva)†

“…In a study on African grey parrots (Psittacus erithacus), raw material particle size did not change nutrient digestibility, but coarse ground feed promoted firmer stools (Kalmar et al, 2007). For pigeons, starch cooking reduced protein and fat digestibility and promoted moist excreta formation (Abd El-Khalek, Kalmar, Van Weyenberg, Werquin, & Janssens, 2009). In a study comparing extruded versus pelleted diets for macaws, the intake of less gelatinized starch in the pelleted diets resulted in reduced glucose, cholesterol and triglyceride concentrations in the plasma (Veloso et al, 2014), a parameter related with some chronic disease of parrots, such as liver diseases and atherosclerosis (Bavelaar & Beynen, 2004), although the pathogenesis of these diseases in parrots is little studied and serum markers are not validated yet.…”