Interactions between starch source and gelatinisation degree on performance and small intestinal digestion in broiler chickens

Abstract

1. A 2 × 2 factorial arrangement was used to test the hypothesis that, in pelleted diets, legume starch is digested less rapidly and to a lesser extent than cereal starch, and that increased gelatinisation through extrusion would eliminate the differences between the starch sources. In addition, the trial examined whether a lower ratio of starch to nitrogen disappearance rate (SNDR) could improve feed conversion ratio (FCR). 2. At 17 d of age, male broilers were randomly distributed among four dietary treatments, consisting of either wheat or faba bean starch-rich fraction (FBS) as the sole starch source and pelleting or extrusion as processing methods. Each treatment had 10 replicate pens containing five birds each. 3. Extrusion resulted in a more extensive starch gelatinisation compared to pelleting, as expected. 4. No difference in weight gain at 29 d of age was observed between birds fed starch sources. However, birds fed wheat tended (P = 0.080) to have better FCR than those fed FBS, while the effect of processing methods was insignificant. Thus, there was no interaction between starch source and processing method on FCR. 5. In pelleted diets, FBS had lower and slower starch digestibility compared to wheat in all intestinal segments (P < 0.05). The interaction between starch source and processing method in all intestinal segments (P < 0.001) demonstrated that FBS responded more to gelatinisation through extrusion than did wheat. Thus, differences in starch digestibility between the wheat and FBS were eliminated with extrusion. 6. Feeding extruded diets significantly increased the upper jejunal expression of GLUT1, GLUT2 and SGLT1 compared to pelleted diets, which suggested that glucose absorption was less likely to be a limiting factor for starch utilisation. 7. Pelleting resulted in a lower ratio (P < 0.001) of SNDR compared to extrusion (on average 1.4-fold) but did not improve FCR.

Dietary amylose and amylopectin ratio changes starch digestion and intestinal microbiota diversity in goslings

“…Many studies have shown that different sources of starch affect the growth performance of animals (Del Alamo et al, 2009;Itani et al, 2021). It has been suggested that feeding SDS may improve FCR of birds.…”

Air-classified faba bean protein fraction as a substitute to soybean meal in pelleted and extruded broiler diets

“…The FBP was obtained following air classification of pinmilled dehulled faba beans (white flowering, low-tannin variety) as described by Itani et al (2020). The SBM was ground to pass through a 1 mm sieve in a hammer mill (Münch-Edelstahl, Wuppertal, Germany licenced by Bliss, USA, 18.5 kW, 3000 RPM) before being mixed with other ingredients.…”

“…Diets were formulated to be isonitrogenous and isoenergetic and to meet or exceed Ross 308 strain average recommendations (Aviagen 2019) for the starter and grower periods for major nutrients (Tables 3 and Tables 4). The SBM-based diet has been presented elsewhere (Itani et al 2020) as part of another experiment.…”

“…Mean body weight and average feed intake at d 17 were not different between pens assigned to each treatment (data not shown), with values of 740 g ± 20 g SD and 860 g ± 20 g SD, respectively. Further details of bird housing and management are given elsewhere (Itani et al 2020). At 17 d of age, the birds were randomly assigned to one of four dietary treatments, giving 10 replicate pens per treatment with five birds per pen.…”

“…The RNA extraction, cDNA synthesis and qPCR were carried out as described by Itani et al (2020). The primers used in the current experiment were sourced from several studies and are shown with the selected genes in Table 6.…”