Differential Effects of Dietary Methionine Isomers on Broilers Challenged with Acute Heat Stress

Abstract

In this study, we investigated the effect of methionine isomers (D-and L-methionine) on growth performance, blood metabolite levels, nutrient digestibility, intestinal morphology, and foot pad dermatitis in broilers challenged with acute heat stress. In total, 240 broilers were randomly allocated in a 2×2 factorial arrangement consisting of two dietary treatments (D-vs. L-methionine) and two thermal environmental conditions (thermo-neutral vs. acute heat stress). Methionine isomers were added to the diet as an ingredient according to the diet formulation. The broilers were exposed to acute heat stress at 33℃ for 5 h on day 14. The average daily gain and feed conversion ratio of birds fed L-methionine were higher than those fed D-methionine (P＜0.05) from the time of hatching till 21 days. Induced acute heat stress impaired (P＜0.05) the daily gain and feed intake of the broilers on day 21. Furthermore, the blood urea nitrogen levels of birds subjected to acute heat stress on days 14 and 21 were higher (P＜0.05) than those of their counterparts. Longer villi (P＜0.05) were observed in broilers fed L-methionine-supplemented diet than in those fed D-methionine-supplemented diet on day 14, irrespective of thermal environmental conditions. Heat stress reduced (P ＜0.01) nutrient digestibility of the broilers on days 14 and 21. Higher incidence and severity of foot pad dermatitis were observed (P＜0.05) in broilers fed diet containing D-methionine than in those fed L-methionine-supplemented diet. In conclusion, L-methionine-supplemented diet improved growth performance, overcame growth depression, and reduced the incidence of foot pad dermatitis when broilers were exposed to acute heat stress in the starter period.

In Ovo Injection of GABA Can Help Body Weight Gain at Hatch, Increase Chick Weight to Egg Weight Ratio, and Improve Broiler Heat Resistance

“…No GABA and temperature effects were detected on body weight and feed intake during the challenge, consistent with the results of Wickramasuriya et al [ 31 ] that acute HS in 14-day-old chicks did not affect growth parameters. These results might be explained by the fact that growth parameters are generally not affected during short-term heat exposure.…”

Multi-tissue transcriptomic analysis reveals that L-methionine supplementation maintains the physiological homeostasis of broiler chickens than D-methionine under acute heat stress

“…There were significant phenotypic differences due to acute heat stress, which have been published previously [13]. The acute heat stress significantly reduced intake and weight gain of chickens regardless of the supplemented methionine isoform.…”

“…The deep-body temperature of the birds during the acute heat stress period (start, 2 h, and 5 h) was measured using a thermistor probe (FlashCheck 1 Tip Probe Thermometer, Weber Scientific, Hamilton, NJ 08691) inserted into the bird's rectum. Heavy panting, dispersed distribution within the cage, and significantly higher rectal temperature ensured us that the birds were sufficiently heat stressed (data were shown in previous paper [13]).…”

“…After heat treatment, all chicks were treated with the same procedure and raised up to five weeks of age in order to investigate the effects of acute heat stress on growth performance. The detailed experimental procedure can be found in a previous study [ 13 ].…”

Resveratrol sustains intestinal barrier integrity, improves antioxidant capacity, and alleviates inflammation in the jejunum of ducks exposed to acute heat stress

“…The villi length and crypt depth ratio (V/C) reflects the digestion and absorption capacity of the intestine ( Wickramasuriya et al, 2019 ). In this study, the V/C of jejunum, and the number of goblet cells in jejunal mucosa were increased by resveratrol, which alleviated intestinal villus congestion and lymphocyte infiltration, effectively protected the intestinal of duck exposed during acute heat stress.…”