Exogenous α-amylase improves the digestibility of corn and corn–soybean meal diets for broilers

Abstract

Starch is the main energy source in broiler diets. However, endogenous amylase secretion in young broilers is suboptimal to completely digest dietary starch, so exogenous α-amylase supplementation may help increase starch digestibility. The objective of this study was to assess the supplementation of increasing doses of an exogenous α-amylase (0, 40, 80, 120, and 160 kilo-novo α-amylase units ( KNU )/kg) on corn and on a complete corn–soybean meal diet for 25-day-old broilers. Jejunal and ileal apparent digestibility coefficients of available starch, resistant starch, total starch, and DM, DM total tract retention, as well as dietary AME levels were evaluated. Interactions ( P < 0.05) between diets and α-amylase showed that the enzyme had a more evident effect on increasing DM jejunal digestibility and AME on corn compared with the complete diet. Corn DM digestibility increased to a maximum of 67.84% with up to 47 KNU/kg, whereas 89 KNU/kg led to a maximum of 53.92% in the complete diet A maximum increase of 64 kcal AME/kg was obtained with 80 KNU/kg on the complete diet, whereas 109 KNU/kg generated 327 kcal AME/kg on corn ( P < 0.05). Increasing the α-amylase dose linearly increased ileal digestibility of resistant starch ( P < 0.05), and the effect on DM total tract retention was quadratic ( P < 0.05). Corn showed a higher digestibility for DM, resistant and total starch, as well as DM total tract retention and AME, compared with the complete diet ( P < 0.05). Treatments had no influence on available starch. The inclusion of exogenous α-amylase improves starch, DM, and energy utilization of corn-based and corn–soybean meal–based diets for broilers.

Liver fat metabolism of broilers regulated by Bacillus amyloliquefaciens TL via stimulating IGF-1 secretion and regulating the IGF signaling pathway

“…Therefore, differences in starch digestive enzymes may affect the rate and extent of starch digestion and change in the blood glucose levels in body, and consequently, affect the indicators of production performance (Svihus, 2014 ; Wolever et al, 2021 ). Studies have shown that the endogenous amylase secretion in broilers is not ideal for the complete digestion of dietary starch (Schramm et al, 2021 ). However, the prominent digestibility of native starch in chickens compared to other species, such as pigs may be due to the high secretion of amylase induced by the pancreatic juice of chickens (Svihus, 2014 ), thus increasing the level of amylase to enhance the starch digestion.…”

Carbohydrases and Phytase in Poultry and Pig Nutrition: A Review beyond the Nutrients and Energy Matrix

“…An increase in starch digestibility is accompanied by a greater release of other nutrients for endogenous enzymatic digestion because the starch granules are incorporated into a matrix that also contains protein and lipids [89]. Thus, a-amylase supplementation improves nutrient and energy digestibility, as demonstrated in broilers [90] and pigs [91].…”

“…Jiang et al [92] observed a decline in pancreatic α-amylase activity ranging from 9% to 33% as exogenous α-amylase levels increased from a 250 mg/kg to a 2250 mg/kg diet. In fact, exogenous enzymes supplementation can be antagonistic to the secretion of some endogenous enzymes [90]. By reducing the need for pancreatic amylase synthesis and reducing intestinal and pancreatic mass [80,93], it is possible to save energy and amino acids, which can be used for enterocyte cell proliferation or other body functions, explaining the improvements observed in intestinal morphology.…”

“…Furthermore, the supplementation of exogenous α-amylase modulating the intestinal microbiota is due to the ability of α-amylase supplementation to act upon undigested starch fractions, which consist of resistant starch known for its "prebiotic" properties [90,94]. However, to the best of our knowledge, the impact of exogenous α-amylase on the microbiota in poultry or pigs has not yet been published.…”