Effects of dietary betaine as a potential choline substitute on growth performance, intestinal histomorphology, tissue malondialdehyde concentrations, and hepatic heat shock protein 70 expression in heat-stressed broilers

Why clinicians should know about it

• Picked for Critical Care and Intensive Care Medicine (top studies of the week, 4 October 2026): High-quality evidence in a top journal

Abstract

This study evaluated the potential of dietary betaine to replace supplemental choline by comparing choline, betaine, or their combination and assessing their effects on growth performance, intestinal histomorphology, tissue malondialdehyde (MDA) concentrations, and hepatic heat shock protein 70 (HSP70) gene expression in broilers exposed to cyclic heat stress (HS). A total of 768 one-day-old male Ross 308 broilers were randomly allocated to six dietary treatments with eight replicates of 16 birds each. Treatments consisted of a control diet without supplemental betaine or choline (CON); recommended choline supplementation (CH-REC; 700, 600, and 500 mg/kg during the starter, grower, and finisher periods, respectively) or equivalent betaine supplementation (BT-MATCH); high-dose choline (CH-HIGH; 1000 mg/kg); high-dose betaine (BT-HIGH; 1000 mg/kg); and combined betaine and choline supplementation (BTCH-MIX; 500 mg/kg each). Cyclic HS was applied from day 25 to 41 at 32 ± 1°C for 6 h daily. During the grower period, CH-REC increased feed intake compared with CON and CH-HIGH (P = 0.034), whereas all supplemented groups showed greater body weight gain (BWG) than CON (P = 0.038). Under HS, CH-REC, BT-MATCH, and BTCH-MIX improved BWG and feed conversion ratio (P < 0.05), whereas mortality did not differ significantly among dietary treatments. Carcass traits, abdominal fat, and liver weight were unaffected by dietary treatments. Dietary supplementation generally improved jejunal histomorphological characteristics, with the most pronounced responses observed in BT-MATCH (P < 0.05). Tissue MDA concentrations were reduced in most supplemented groups (P < 0.05), except in liver samples of CH-REC birds. Hepatic HSP70 gene expression increased in all supplemented groups except CH-REC (P < 0.001). Overall, these findings suggest that betaine may partially substitute for supplemental choline in corn-soybean meal-based diets under cyclic HS conditions. Choline-equivalent betaine supplementation (BT-MATCH) supported growth performance and favorable responses in jejunal histomorphology and tissue MDA concentrations, together with treatment-related differences in hepatic HSP70 gene expression, whereas higher betaine supplementation provided no additional benefit.

Abstract as published, via PubMed.