Interactive effect of dietary calcium and phytase on broilers challenged with subclinical necrotic enteritis: part 2. Gut permeability, phytate ester concentrations, jejunal gene expression, and intestinal morphology

Abstract

Calcium has the capacity to interact with phytate-P to form Ca-phytate complexes and decrease the ability of exogenous phytase to degrade phytic acid. This study investigated the hypothesis that high dietary Ca would impair gut permeability, phytate esters (inositol x-phosphate, IPx: IP3, IP4, IP5, and IP6) degradation, jejunal gene expression, and intestinal morphology. Ross 308 day-old male broilers (n = 768) were distributed into 48-floor pens each housing 16 birds in a factorial arrangement. Factors were NE challenge—no or yes; phytase level of 500 or 1,500 FTU/kg, and Ca level 0.6 or 1.0% starter, 0.5 or 0.9% grower, 0.4 or 0.8% finisher with available P in each phase. Challenged birds were gavaged with 3 field strains of Eimeria on day 9 and 10 8 CFU per mL of Clostridium perfringens Strain EHE-NE18 on day 14 and day 15. A phytase × Ca interaction was observed in the ileum for IP3 ( P < 0.01), IP4 ( P < 0.05), and IP6 ( P < 0.01). The IP3 and IP4 concentrations were similar for both doses of phytase in the presence of low Ca, but with high Ca, both increased significantly but to a greater extent when the high dose of phytase was used. While IP6 concentrations were low and similar between both doses of phytase at low Ca levels, increasing dietary Ca levels increased IP6 concentrations regardless of phytase dose, but the effect was greater in the low phytase diet. A phytase × Ca interaction was detected for vitamin D receptor (VDR) ( P < 0.05) expression where bird fed low phytase and low Ca recorded the highest expression of VDR, all other treatments being equivalent. The challenge decreased crypt depth to villus height ratio ( P < 0.001). Challenge birds had higher fluorescein isothiocyanate dextran ( P < 0.05) in blood compared with unchallenged birds. Thus, high Ca and high phytase, while not the best for IP6 destruction, did not lead to huge reductions in indicators of gut health.

Effects of phytase and coccidial vaccine on growth performance, nutrient digestibility, bone mineralization, and intestinal gene expression of broilers

“… Proszkowiec-Weglarz et al (2019) reported that CASR plays a key role in regulating calcium homeostasis of chickens and exists in Ca 2+ regulatory tissues such as parathyroid, kidney, and intestine. Through CASR, parathyroid chief cells can maintain Ca 2+ concentrations in plasma by modulating release of parathyroid hormone into the circulation, and its levels are influenced by plasma vitamin D 3 and Ca ( Zanu et al, 2020 ). The characterization of CASR in intestinal epithelial cells indicates that CASR may mediate Ca 2+ absorption ( Gama, et al, 1997 ).…”

Transversal gene expression panel to evaluate intestinal health in broiler chickens in different challenging conditions

“…In agreement with this hypothesis, Su et al 12 reported that SLC15A1 mRNA levels were decreased in the jejunum and increased in the ileum of Eimeria acervulina -challenged layers. C.perfringens -challenged chickens showed a down-regulation of SLC34A2 gene, which is involved in regulating both intestinal Pi (phosphate) absorption and renal Pi resorption, and of VDR gene, a transcription factor that mediates the vitamin D3, involved in signalling intestinal calcium and phosphate absorption 16 . This reduction of SLC34A2 may be explained by the decrease of mTOR , known to stimulate many intestinal NTers including SLC34A2 17 .…”

Supplementation of reduced protein diets with

“…Five villi per section were randomly selected for measurements of villus height, crypt depth, basal width, middle width, and apical width, resulting in 10 measurements per sample and 30 measurements per pen. The apparent villus surface area was calculated as (basal width + apical width)/2 × villus height, following Zanu et al (2020b).…”