Glucose Supplementation Improves Performance and Alters Glucose Transporters' Expression in Pectoralis major of Heat-Stressed Chickens

Simple Summary: Heat stress (HS) is a major challenge in poultry production as it alters basic metabolism and slows growth. The reduction in feed intake (FI), induced by heat stress is a major determinant as it reduces glucose intake and level in the tissues of broiler chickens. Reduced tissue glucose level causes a reduction in the energy level of birds, hence increasing gluconeogenesis (i.e., utilizing muscle protein to produce glucose). This results in poor carcass yield and economic losses. We aimed at sustaining tissue glucose of birds subjected to cyclic HS via glucose supplementation. Heat stress decreased the performance of the birds while glucose supplementation salvaged some of the losses that could have been incurred under HS. The expression of SGLT1 was pronounced in the glucose supplemented groups while GLUTs 1, 5 and 10 were highly expressed in birds subjected to HS. Sustaining tissue glucose level of birds may aid in the mitigation of some of the detrimental effects of HS. Glucose level in birds' tissue decreases due to heat stress (HS)-induced reduction in feed intake (FI); impairing metabolism and growth. The effect of glucose supplementation on the performance of broiler chickens was evaluated under thermoneutral (TN) and HS conditions. Glucose was supplemented at 0 and 6% under TN-(25 degrees C) and HS-(25 degrees C-35 degrees C-25 degrees C) conditions. The treatments were TN + 0%-glucose (TN0); TN + 6%-glucose (TN6), HS + 0%-glucose (HS0) and HS + 6%-glucose (HS6). There were 6 replicates (19 birds each)/treatment. Heat and glucose supplementation were applied from d28-35. At d35, Pectoralis (P.) major was sampled from one bird/replicate to determine glucose transporters' mRNA expression. Heat application lowered (p < 0.05) FI, body weight gain, and increased feed and water conversion ratios. Glucose supplementation increased total energy intake by 4.9 and 3.2% in TN and HS groups, respectively but reduced FI under TN and HS conditions. The P. major- and drumstick-yield reduced (p < 0.05) in HS0 compared to TN0, TN6 and HS6. Under HS, glucose supplementation improved eviscerated carcass weight by 9% and P. major yield by 14%. Glucose supplementation increased SGLT1 expression with/without heat treatment while HS independently increased the expression of GLUT 1, 5 and 10. Glucose supplementation under HS could improve performance of broilers.